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Sample records for marsh american midland

  1. The East Midlands in 2006: the demography of the East Midlands

    OpenAIRE

    Lawton, C

    2006-01-01

    The East Midlands in 2006 is the evidence base that was produced to underpin the devleopment of the regional economic strategy, A Flourishing Region. This document presents detailed analysis of the demography of the East Midlands.

  2. Transcendental Trinitarian: James Marsh, the Free Will Problem, and the American Intellectual Context of Coleridge’s Aids to Reflection

    Directory of Open Access Journals (Sweden)

    Jonathan Koefoed

    2017-08-01

    Full Text Available Historians of American religion and Transcendentalism have long known of James Marsh as a catalyst for the Concord Transcendentalist movement. The standard narrative suggests that the Congregationalist Marsh naively imported Samuel Taylor Coleridge's Aids to Reflection (Am. ed. 1829 hoping to revivify orthodoxy in America. By providing a “Preliminary Essay” to explain Coleridge’s abstruse theology, Marsh injected Coleridge’s hijacked Kantian epistemology—with its distinction between Reason and Understanding—into American discourse. This epistemology inspired Transcendentalists such as Ralph Waldo Emerson and Bronson Alcott, and it helped spark the Transcendentalists’ largely post-Christian religious convictions. This article provides a re-evaluation of Marsh’s philosophical theology by attending to the precise historical moment that Marsh chose to publish the Aids to Reflection and his “Preliminary Essay.” By the late 1820s, the philosophical problem of free will lurked in American religious discourse—Unitarian as well as Trinitarian—and Marsh sought to exploit the problem as a way to explain how aspects of Trinitarian Christianity might be rational and yet unexplainable. Attending carefully to the numerous philosophical and religious discourses of the moment—including Unitarianism, Trinitarianism, Kant, Coleridge, and Scottish Common Sense—and providing close readings of the historical philosophers Marsh engaged, this article shows how James Marsh laid the epistemological groundwork for a new romanticized Christianity that was distinct from the Concord Transcendentalists, but nonetheless part of its historical lineage.

  3. Legal advocacy and nuclear power: the impact of litigation on the Midland nuclear plant

    International Nuclear Information System (INIS)

    Cook, C.E.

    1979-01-01

    The use of litigation as an interest-group strategy is analyzed in relation to the controversy over the development of nuclear power. An assessment is made of the impact of the judicial process, with the litigation involving the Midland, Michigan, nuclear plant serving as a representative case study. In the construction permit hearings for the Midland nuclear plant, which began in 1970, the interest groups were Consumers Power Company, a Michigan utility, and the Saginaw and Mapleton Intervernors, environmentalists dwelling near the proposed plant site. The Nuclear Regulatory Commission issued a construction permit for the plant after a two-year licensing process, but the environmental groups appealed the permit to the United States Court of Appeals for the District of Columbia Circuit. In 1976, the permit was remanded by the court to the Commission for reconsideration, and Consumers Power Company appealed that decision. In 1978, the Supreme Court handed down a unanimous and definitive opinion, Consumers Power Company vs Aeschliman, that upheld the Commission's original issuance of the construction plant. The Midland case well illustrates the detrimental impact that legal advocacy has had on atomic energy by prolonging the regulatory process. The positive consequences of the Court ruling favoring the utility's position were outweighed by the expense involved in the initial ten years of thelicensing and subsequent lawsuits concerning the Midland plant. Consequently, Consumers Power Company is representative of most other American electric companies in its determination that it cannot build additional nuclear plants without mitigation of the uncertainty and duration of the regulatory process. Thus, it may be concluded that the environmental groups' use of legal advocacy at Midland and elsewhere has proven to be an effective strategy for undermining the nuclear industry and for deterring the future development of nuclear power

  4. Destination 2010: regional economic strategy for the East Midlands 2003-2010

    OpenAIRE

    East Midlands Development Agency

    2003-01-01

    Destination 2010 is the second regional economic strategy for the East Midlands. The strategy is a high level framework that sets out a vision for the East Midlands economy in 2010 and provides a blueprint for economic development activity in the region for the period 2003-2010.

  5. East Midlands healthcare and bioscience sector strategy

    OpenAIRE

    East Midlands Development Agency

    2007-01-01

    The healthcare and bioscience sector is one of four priority sectors identified in the regional economic strategy, A Flourishing Region. This document sets out a strategy for maximising the contribution of the healthcare and biosciences sector to the economic development of the East Midlands.

  6. Nuclear power plant diagnostics study at the Midland Training Simulator

    International Nuclear Information System (INIS)

    Reifman, J.; Rank, P.; Lee, J.C.; Wehe, D.K.

    1991-01-01

    This paper discusses the implementation of two advanced diagnostic concepts for nuclear power plant diagnostics, the systematic generation and updating of a rule-based system and the simulation filter, at the Midland Nuclear Power Plant Unit 2 Training Simulator. The authors use an entropy minimax pattern recognition algorithm for the systematic construction of the diagnostic rule base. By extracting information from a transient database constructed with the Midland Simulator, the algorithm searches for trends in plant parameters, forming patterns or rules that describe the behavior of the transients. The rules are updated in an incremental manner within the context of the entropy minimax algorithm. The simulation filter is a nonlinear parameter estimation algorithm based on the extended Kalman filter. The authors use the simulation filter to improve the results of crude simulation models by optimally estimating system states given a set of measurements and results from a nonlinear simulation program. The Midland Simulator results of the Three Mile Island accident are significantly improved with the use of the simulation filter

  7. Lapses haunt Midland A-plant

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    The US's first nuclear cogeneration project (Consumer's Power Co.) broke ground 11 years ago, in Midland, Michigan. From the beginning, it has been plagued by lawsuits, stiff new regulations on safety from the NRC, breakdowns in several quality assurance programs and major foundation problems. The two unit station is getting a new turbine-auxiliary building foundation, at a cost of $250 million, due to poorly compacted soils which caused extensive settlement in some areas

  8. Midland reactor pressure vessel flaw distribution

    International Nuclear Information System (INIS)

    Foulds, J.R.; Kennedy, E.L.; Rosinski, S.T.

    1993-12-01

    The results of laboratory nondestructive examination (NDE), and destructive cross-sectioning of selected weldment sections of the Midland reactor pressure vessel were analyzed per a previously developed methodology in order to develop a flaw distribution. The flaw distributions developed from the NDE results obtained by two different ultrasonic test (UT) inspections (Electric Power Research Institute NDE Center and Pacific Northwest Laboratories) were not statistically significantly different. However, the distribution developed from the NDE Center's (destructive) cross-sectioning-based data was found to be significantly different than those obtained through the UT inspections. A fracture mechanics-based comparison of the flaw distributions showed that the cross-sectioning-based data, conservatively interpreted (all defects considered as flaws), gave a significantly lower vessel failure probability when compared with the failure probability values obtained using the UT-based distributions. Given that the cross-sectioning data were reportedly biased toward larger, more significant-appearing (by UT) indications, it is concluded that the nondestructive examinations produced definitively conservative results. In addition to the Midland vessel inspection-related analyses, a set of twenty-seven numerical simulations, designed to provide a preliminary quantitative assessment of the accuracy of the flaw distribution method used here, were conducted. The calculations showed that, in more than half the cases, the analysis produced reasonably accurate predictions

  9. Primary coolant feed and bleed operating regions for the Midland Plant

    International Nuclear Information System (INIS)

    Tsai, M.S.

    1985-01-01

    Operating regions for primary coolant feed and bleed cooling are developed for the Midland Plant using core decay heat, the high-pressure injection (HPI) system capacity, and flow rate relief through the power-operated relief valve (PORV). This mode of cooling is used for accident scenarios in which the normal core cooling means of a nuclear power plant is lost because of loss of water inventory in the steam generators. The HPI flow is based on the capacities of one and two pumps. Saturated steam, saturated water, and subcooled water are considered to be possible states of the fluid being relieved through the PORV. In estimating the PORV relief rate, flow equations are derived from the Electric Power Research Institute test data obtained from the same model and size valve that is used in the Midland Plant. For easy reference by operators, the operating region is displayed on a plane of reactor coolant system pressure and temperature. The technique developed for the Midland Plant provides a convenient method for examining the feed and bleed cooling capability for a nuclear power plant that employs a pressurized water reactor system

  10. Multiple lines of evidence risk assessment of American robins exposed to polychlorinated dibenzofurans (PCDFS) and polychlorinated dibenzo-P-dioxins (PCDDS) in the Tittabawassee River floodplain, Midland, Michigan, USA.

    Science.gov (United States)

    Tazelaar, Dustin L; Fredricks, Timothy B; Seston, Rita M; Coefield, Sarah J; Bradley, Patrick W; Roark, Shaun A; Kay, Denise P; Newsted, John L; Giesy, John P; Bursian, Steven J; Zwiernik, Matthew J

    2013-06-01

    Concentrations of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) in Tittabawassee River floodplain soils and biota downstream of Midland, Michigan, USA, are greater than regional background concentrations. From 2005 to 2008, a multiple lines of evidence approach was utilized to evaluate the potential for effects of PCDD/DFs on American robins (Turdus migratorius) breeding in the floodplains. A dietary-based assessment indicated there was potential for adverse effects for American robins predicted to have the greatest exposures. Conversely, a tissue-based risk assessment based on site-specific PCDD/DF concentrations in American robin eggs indicated minimal potential for adverse effects. An assessment based on reproductive endpoints indicated that measures of hatch success in study areas were significantly less than those of reference areas. However, there was no dose-response relationship between that endpoint and concentrations of PCDD/DF. Although dietary-based exposure and reproductive endpoint assessments predicted potential for adverse effects to resident American robins, the tissue-based assessment indicates minimal to no potential for adverse effects, which is reinforced by the fact the response was not dose related. It is likely that the dietary assessment is overly conservative given the inherent uncertainties of estimating dietary exposure relative to direct tissue-based assessment measures. Based on the available data, it can be concluded that exposure to PCDD/DFs in the Tittabawassee River floodplain would not likely result in adverse population-level effects to American robins. Copyright © 2013 SETAC.

  11. Heterophil/Lymphocyte Alterations as a Measure of Stress in American Alligators in Relation to Anthropogenic Disturbance in a Louisiana Intermediate Marsh

    Directory of Open Access Journals (Sweden)

    Christopher M. Murray

    2015-05-01

    Full Text Available Numerous anthropogenic factors represent environmental threats to Gulf Coast wetland ecosystems and associated fauna. American alligators (Alligator mississippiensis have been subject to long-term management and used as ecological and physiological indicators of habitat quality in response to anthropogenic events and stochastic natural disasters. The present study monitored heterophil to lymphocyte ratios (an indicator of stress, in American alligators in a Louisiana intermediate marsh from 2009 to 2011, a time period that coincides with an oil inundation event that occurred in 2011. Sixteen alligators were observed and processed morphometrically (total length, snout-vent length and body mass. Heterophil to lymphocyte ratios were negatively correlated with size, suggesting larger American alligators were physiologically more resilient to the disturbance, more able to actively avoid these poor conditions, or are less affected by localized disturbance.

  12. Design and construction of the liner plate for the Arkansas and Midland containments

    International Nuclear Information System (INIS)

    Wiedner, K.; Shah, G.H.; Chang-Lo, P.

    1976-01-01

    This paper presents the design criteria and features of the containment liner plate systems utilized for the Arkansas and Midland Nuclear Power Plant. For the Arkansas project, the liner plate system was erected in circumferential rings approximately 3 m high, and the penetration assemblies were welded into the liner after erection. For the Midland project, the liner plate system was erected in vertical segments approximately 6 m wide x 24 m high, and the penetration assemblies were welded into the liner prior to erection. The differences between the schemes are discussed. (author)

  13. Midland Plant, Units 1 and 2 (Docket Nos. 50-329 and 50-330): Draft supplement to the Final environmental statement

    International Nuclear Information System (INIS)

    1977-01-01

    The Midland Plant, Units 1 and 2 is to be owned and operated by the Consumers Power Company of Michigan. The approximately 1190-acre plant is on the south of the Tittabawassee River immediately across from the Dow Chemical Company's main industrial complex which is within the Midland city limits. The site itself was, and the area south of the site is, partially wooded flat land with farming the only economically significant human activity. To the east and north within one mile of the site, the land is industrial, both developed and undeveloped. To the west, the land is used for suburban residences and light farming. The plant will utilize two pressurized-water nuclear reactor systems. The Consumers Power Company filed with AEC (now NRC) an application for construction permits and operating licenses for the Midland Plant on January 13, 1969. The Final Environmental Statement was issued in March 1972 and on December 15, 1972 construction permits were issued for the Midland Plant. On July 21, 1976, the US Court of Appeals for the District of Columbia Circuit handed down decisions in the generic fuel cycle rulemaking and Midland appeals ruling that nuclear waste disposal and fuel reprocessing issues had been insufficiently considered by the AEC. In addition to consideration of the fuel cycle issues, the Court of Appeals remanded Consumer Power's construction permits for Midland to the NRC for further proceedings to consider energy conservation as an alternative to plant construction, and to consider any changed circumstances concerning the need of Dow for the process steam from the Midland Plant. 10 refs., 13 tabs

  14. The West Midlands breast cancer screening status algorithm - methodology and use as an audit tool.

    Science.gov (United States)

    Lawrence, Gill; Kearins, Olive; O'Sullivan, Emma; Tappenden, Nancy; Wallis, Matthew; Walton, Jackie

    2005-01-01

    To illustrate the ability of the West Midlands breast screening status algorithm to assign a screening status to women with malignant breast cancer, and its uses as a quality assurance and audit tool. Breast cancers diagnosed between the introduction of the National Health Service [NHS] Breast Screening Programme and 31 March 2001 were obtained from the West Midlands Cancer Intelligence Unit (WMCIU). Screen-detected tumours were identified via breast screening units, and the remaining cancers were assigned to one of eight screening status categories. Multiple primaries and recurrences were excluded. A screening status was assigned to 14,680 women (96% of the cohort examined), 110 cancers were not registered at the WMCIU and the cohort included 120 screen-detected recurrences. The West Midlands breast screening status algorithm is a robust simple tool which can be used to derive data to evaluate the efficacy and impact of the NHS Breast Screening Programme.

  15. Report on accreditation learning sets in the West Midlands region of the NHS.

    Science.gov (United States)

    Giles, G

    2000-12-01

    This article reports on the evaluation of the first year of a project, which utilized learning sets to support librarians undergoing the accreditation process, in the health libraries in the West Midlands region of the NHS. The West Midlands Health region is divided up into education consortia patches. Each group of patch librarians was allocated a local accreditation facilitator. The groups met regularly to discuss problems and progress relating to their library's accreditation. The results of the evaluation suggest that this is a valuable approach to use. The recommendations state that regular, frequent meetings are needed. Extra training and guidance would help the facilitators to be more effective in their role.

  16. Will Restored Tidal Marshes Be Sustainable?

    Directory of Open Access Journals (Sweden)

    Michelle Orr

    2003-10-01

    Full Text Available We assess whether or not restored marshes in the San Francisco Estuary are expected to be sustainable in light of future landscape scale geomorphic processes given typical restored marsh conditions. Our assessment is based on a review of the literature, appraisal of monitoring data for restored marshes, and application of vertical accretion modeling of organic and inorganic sedimentation. Vertical accretion modeling suggests that salt marshes in San Pablo Bay will be sustainable for moderate relative sea level rise (3 to 5 mm yr-1 and average sediment supply (c. 100 mg L-1. Accelerated relative sea level rise (above 6 mm yr-1 and/or reduced sediment supply (50 mg L-1 will cause lowering of the marsh surface relative to the tide range and may cause shifts from high to low marsh vegetation by the year 2100. Widespread conversion of marsh to mudflat-"ecological drowning"-is not expected within this time frame. Marshes restored at lower elevations necessary to aid the natural development of channel systems (c. 0.5 m below mean higher high water are predicted to accrete to high marsh elevations by the year 2100 for moderate relative sea level rise and sediment supply conditions. Existing rates of sediment accretion in restored fresh water tidal marshes of the Delta of greater than 9 mm yr-1 and slightly lower drowning elevations suggest that these marshes will be resilient against relatively high rates of sea level rise. Because of higher rates of organic production, fresh water marshes are expected to be less sensitive to reduced sediment availability than salt marshes. The ultimate long-term threat to the sustainability of tidal marshes is the interruption of coastal rollover-the process by which landward marsh expansion in response to sea level rise compensates for shoreline erosion. Bay front development now prevents most landward marsh expansion, while shoreline erosion is expected to accelerate as sea level rises.

  17. Ecogeomorphology of Spartina patens-dominated tidal marshes: Soil organic matter accumulation, marsh elevation dynamics, and disturbance

    Science.gov (United States)

    Cahoon, D.R.; Ford, M.A.; Hensel, P.F.; Fagherazzi, Sergio; Marani, Marco; Blum, Linda K.

    2004-01-01

    Marsh soil development and vertical accretion in Spartina patens (Aiton) Muhl.-dominated tidal marshes is largely dependent on soil organic matter accumulation from root-rhizome production and litter deposition. Yet there are few quantitative data sets on belowground production and the relationship between soil organic matter accumulation and soil elevation dynamics for this marsh type. Spartina patens marshes are subject to numerous stressors, including sea-level rise, water level manipulations (i.e., flooding and draining) by impoundments, and prescribed burning. These stressors could influence long-term marsh sustainability by their effect on root production, soil organic matter accumulation, and soil elevation dynamics. In this review, we summarize current knowledge on the interactions among vegetative production, soil organic matter accumulation and marsh elevation dynamics, or the ecogeomorphology, of Spartina patens-dominated tidal marshes. Additional studies are needed of belowground production/decomposition and soil elevation change (measured simultaneously) to better understand the links among soil organic matter accumulation, soil elevation change, and disturbance in this marsh type. From a management perspective, we need to better understand the impacts of disturbance stressors, both lethal and sub-lethal, and the interactive effect of multiple stressors on soil elevation dynamics in order to develop better management practices to safeguard marsh sustainability as sea level rises.

  18. Biosphere 2's Marsh Biome

    Science.gov (United States)

    Molnar, Jennifer; Goodridge, Kelven

    1997-01-01

    The Marsh Biome, which was modeled after the mangroves and marshes of southwest Florida, has an area of 441.2 sq m separated into three hydrologically independent sections: the Freshwater, Oligohaline and Salt Marshes. The divisions are made based on their salinity (approximately 0, 4, and 34 ppt. respectively), but they also contain different biological communities. The Freshwater and Oligohaline Marshes are mostly filled with various grasses and several trees, while the Salt Marsh houses regions of red, black, and white mangroves (Rhizophora mangle, Avicennia germinans, and Languncularia racemosa respectively). Overall, there are an estimated 80 species of plants within the biome. Water in the Salt Marsh follows a meandering stream from the algal turf scrubbers (apparatuses that clean the water of its nutrients and heavy metals while increasing dissolved oxygen levels) which have an outlet in the Salt Marsh section near sites 4 and 5 to the Fringing Red Mangrove section. The sections of the Salt Marsh are separated by walls of concrete with openings to allow the stream to flow through. Throughout this study, conducted through the months of June and July, many conditions within the biome remained fairly constant. The temperature was within a degree or two of 25 C, mostly depending on whether the sample site was in direct sunlight or shaded. The pH throughout the Salt Marsh was 8.0 +/- 0.2, and the lower salinity waters only dropped below this soon after rains. The water rdepth and dissolved oxygen varied, however, between sites.

  19. Hydrology of Fritchie Marsh, coastal Louisiana

    Science.gov (United States)

    Kuniansky, E.L.

    1985-01-01

    Fritchie Marsh, near Slidell, Louisiana, is being considered as a disposal site for sewage effluent. A two-dimensional, finite element, surface water modeling systems was used to solve the shallow water equations for flow. Factors affecting flow patterns are channel locations, inlets, outlets, islands, marsh vegetation, marsh geometry, stage of the West Pearl River, flooding over the lower Pearl River basin, gravity tides, wind-induced currents, and sewage discharge to the marsh. Four steady-state simulations were performed for two hydrologic events at two rates of sewage discharge. The events, near tide with no wind or rain and neap tide with a tide differential across the marsh, were selected as worst-case events for sewage effluent dispersion and were assumed as steady state events. Because inflows and outflows to the marsh are tidally affected, steady state simulations cannot fully define the hydraulic characteristics of the marsh for all hydrologic events. Model results and field data indicate that, during near tide with little or no rain, large parts of the marsh are stagnant; and sewage effluent, at existing and projected flows, has minimal effect on marsh flows. (USGS)

  20. Final environmental statement related to construction of Midland Plant, Units 1 and 2 (Docket Nos. 50-329 and 50-330)

    International Nuclear Information System (INIS)

    1977-01-01

    This is a Final Detailed Statement on Environmental Considerations associated with construction and operation of Midland Plant Units 1 and 2 at Midland, Michigan, pursuant to a construction permit and operating license which has been applied for by the Consumers Power Company. The application is under review by the US Atomic Energy Commission's Regulatory Staff. The environmental impact, including adverse and beneficial effects, of the Midland Plant includes reassignment of use of about 1100 acres of agricultural and residential land for the cooling pond (the plant buildings are located on industrial zoned land); this resulted in the dislocation of approximately 25 residences and relocation of the Midland County Farm to a newly built structure; the destruction of a maximum of 4400 tons of phytoplankton per year at the intake of makeup water from the Tittabawassee River; and a predicted small increase in fogging effects in the near vicinity of the cooling pond. 34 refs., 19 figs., 26 tabs

  1. Sea level driven marsh expansion in a coupled model of marsh erosion and migration

    Science.gov (United States)

    Kirwan, Matthew L.; Walters, David C.; Reay, William G.; Carr, Joel

    2016-01-01

    Coastal wetlands are among the most valuable ecosystems on Earth, where ecosystem services such as flood protection depend nonlinearly on wetland size and are threatened by sea level rise and coastal development. Here we propose a simple model of marsh migration into adjacent uplands and couple it with existing models of seaward edge erosion and vertical soil accretion to explore how ecosystem connectivity influences marsh size and response to sea level rise. We find that marsh loss is nearly inevitable where topographic and anthropogenic barriers limit migration. Where unconstrained by barriers, however, rates of marsh migration are much more sensitive to accelerated sea level rise than rates of edge erosion. This behavior suggests a counterintuitive, natural tendency for marsh expansion with sea level rise and emphasizes the disparity between coastal response to climate change with and without human intervention.

  2. Hydrologic aspects of marsh ponds during winter on the Gulf Coast Chenier Plain, USA: Effects of structural marsh management

    Science.gov (United States)

    Bolduc, F.; Afton, A.D.

    2004-01-01

    The hydrology of marsh ponds influences aquatic invertebrate and waterbird communities. Hydrologic variables in marsh ponds of the Gulf Coast Chenier Plain are potentially affected by structural marsh management (SMM: levees, water control structures and impoundments) that has been implemented since the 1950s. Assuming that SMM restricts tidal flows and drainage of rainwater, we predicted that SMM would increase water depth, and concomitantly decrease salinity and transparency in impounded marsh ponds. We also predicted that SMM would increase seasonal variability in water depth in impounded marsh ponds because of the potential incapacity of water control structures to cope with large flooding events. In addition, we predicted that SMM would decrease spatial variability in water depth. Finally, we predicted that ponds of impounded freshwater (IF), oligohaline (IO), and mesohaline (IM) marshes would be similar in water depth, temperature, dissolved oxygen (O2), and transparency. Using a priori multivariate analysis of variance (MANOVA) contrast, we tested these predictions by comparing hydrologic variables within ponds of impounded and unimpounded marshes during winters 1997-1998 to 1999-2000 on Rockefeller State Wildlife Refuge, near Grand Chenier, Louisiana. Specifically, we compared hydrologic variables (1) between IM and unimpounded mesohaline marsh ponds (UM); and (2) among IF, IO, and IM marshes ponds. As predicted, water depth was higher and salinity and O2 were lower in IM than in UM marsh ponds. However, temperature and transparency did not differ between IM and UM marsh ponds. Water depth varied more among months in IM marsh ponds than within those of UM marshes, and variances among and within ponds were lower in IM than UM marshes. Finally, all hydrologic variables, except salinity, were similar among IF, IO, and IM marsh ponds. Hydrologic changes within marsh ponds due to SMM should (1) promote benthic invertebrate taxa that tolerate low levels of O2 and

  3. 75 FR 25887 - Order of Suspension of Trading; In the Matter of Alyn Corp., American HealthChoice, Inc...

    Science.gov (United States)

    2010-05-10

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] Order of Suspension of Trading; In the Matter of Alyn Corp., American HealthChoice, Inc., American Holding Investments, Inc., American Midland Corp... Amwest Environmental Group, Inc. May 6, 2010. It appears to the Securities and Exchange Commission that...

  4. CO2 and CH4 fluxes in a Spartina salt marsh and brackish Phragmites marsh in Massachusetts

    Science.gov (United States)

    Tang, J.; Wang, F.; Kroeger, K. D.; Gonneea, M. E.

    2017-12-01

    Coastal salt marshes play an important role in global and regional carbon cycling. Tidally restricted marshes reduce salinity and provide a habitat suitable for Phragmites invasion. We measured greenhouse gas (GHG) emissions (CO2 and CH4) continuously with the eddy covariance method and biweekly with the static chamber method in a Spartina salt marsh and a Phragmites marsh on Cape Cod, Massachusetts, USA. We did not find significant difference in CO2 fluxes between the two sites, but the CH4 fluxes were much higher in the Phragmites site than the Spartina marsh. Temporally, tidal cycles influence the CO2 and CH4 fluxes in both sites. We found that the salt marsh was a significant carbon sink when CO2 and CH4 fluxes were combined. Restoring tidally restricted marshes will significantly reduce CH4 emissions and provide a strong ecosystem carbon service.

  5. Salt Marsh Bacterial Communities before and after the Deepwater Horizon Oil Spill.

    Science.gov (United States)

    Engel, Annette Summers; Liu, Chang; Paterson, Audrey T; Anderson, Laurie C; Turner, R Eugene; Overton, Edward B

    2017-10-15

    communities in coastal marshes is poorly known, with limited investigation of potential changes in bacterial communities in response to various environmental stressors. The Deepwater Horizon oil spill provided an unprecedented opportunity to study the long-term effects of an oil spill on microbial systems in marshes. Compared to previous studies, the significance of our research stems from (i) a broader geographic range of studied marshes, (ii) an extended time frame of data collection that includes prespill conditions, (iii) a more accurate procedure using biomarker indices to understand oiling, and (iv) an examination of other potential stressors linked to in situ environmental changes, aside from oil exposure. Copyright © 2017 American Society for Microbiology.

  6. Modeling tidal marsh distribution with sea-level rise: evaluating the role of vegetation, sediment, and upland habitat in marsh resiliency.

    Science.gov (United States)

    Schile, Lisa M; Callaway, John C; Morris, James T; Stralberg, Diana; Parker, V Thomas; Kelly, Maggi

    2014-01-01

    Tidal marshes maintain elevation relative to sea level through accumulation of mineral and organic matter, yet this dynamic accumulation feedback mechanism has not been modeled widely in the context of accelerated sea-level rise. Uncertainties exist about tidal marsh resiliency to accelerated sea-level rise, reduced sediment supply, reduced plant productivity under increased inundation, and limited upland habitat for marsh migration. We examined marsh resiliency under these uncertainties using the Marsh Equilibrium Model, a mechanistic, elevation-based soil cohort model, using a rich data set of plant productivity and physical properties from sites across the estuarine salinity gradient. Four tidal marshes were chosen along this gradient: two islands and two with adjacent uplands. Varying century sea-level rise (52, 100, 165, 180 cm) and suspended sediment concentrations (100%, 50%, and 25% of current concentrations), we simulated marsh accretion across vegetated elevations for 100 years, applying the results to high spatial resolution digital elevation models to quantify potential changes in marsh distributions. At low rates of sea-level rise and mid-high sediment concentrations, all marshes maintained vegetated elevations indicative of mid/high marsh habitat. With century sea-level rise at 100 and 165 cm, marshes shifted to low marsh elevations; mid/high marsh elevations were found only in former uplands. At the highest century sea-level rise and lowest sediment concentrations, the island marshes became dominated by mudflat elevations. Under the same sediment concentrations, low salinity brackish marshes containing highly productive vegetation had slower elevation loss compared to more saline sites with lower productivity. A similar trend was documented when comparing against a marsh accretion model that did not model vegetation feedbacks. Elevation predictions using the Marsh Equilibrium Model highlight the importance of including vegetation responses to sea

  7. Safety evaluation report related to the operation of Midland Plant, Units 1 and 2. Docket Nos. 50-329 and 50-330, Consumers Power Company

    International Nuclear Information System (INIS)

    1982-10-01

    This report supplements the Safety Evaluation Report related to the Operation of Midland Plant, Units 1 and 2 (SER) (NUREG-0793) issued in May 1982 by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission with respect to the application filed by Consumers Power Company, as applicant and owner, for licenses to operate the Midland Plant, Units 1 and 2 (Docket Nos. 50-329 and 50-330). The facility is located in the city of Midland in Midland County, Michigan. This supplement provides recent information regarding resolution of the soils settlement issue, one of the open items identified in the SER. Certain confirmatory issues identified in the SER also are addressed

  8. The marshes in Bogota

    International Nuclear Information System (INIS)

    Garcia Romero, Juan F; Moreno Gutierrez, Vanesa; Villalba Malaver, Juan Carlos

    1998-01-01

    A description is made, a diagnosis and some exits, to their preservation for each one of the 10 marshes that they still exist in Bogota. The marshes defines them the convention of Ramsar: As extensions of swamps, swamps or peat-bogs covered with water, be these of natural or artificial, permanent or temporary, stagnated regime or currents, sweet, salubrious or salted, included those of extensions of marine water whose depth in tide lowers don't exceed six meters. The marshes occupy the space that there are between the humid means and the dry means, and that they possess characteristic of both, for what they cannot be classified categorically as aquatic neither terrestrial. The characteristic of a marsh is the presence of water during sufficiently lingering periods as to alter the soils, their microorganisms and the flora and fauna communities

  9. Organic carbon isotope systematics of coastal marshes

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Lubberts, R.K.; Van de Plassche, O.

    1997-01-01

    Measurements of nitrogen, organic carbon and delta(13)C are presented for Spartina-dominated marsh sediments from a mineral marsh in SW Netherlands and from a peaty marsh in Massachusetts, U.S.A. delta(13)C Of organic carbon in the peaty marsh sediments is similar to that of Spartina material,

  10. Sedimentation and response to sea-level rise of a restored marsh with reduced tidal exchange: Comparison with a natural tidal marsh

    Science.gov (United States)

    Vandenbruwaene, W.; Maris, T.; Cahoon, D.R.; Meire, P.; Temmerman, S.

    2011-01-01

    Along coasts and estuaries, formerly embanked land is increasingly restored into tidal marshes in order to re-establish valuable ecosystem services, such as buffering against flooding. Along the Scheldt estuary (Belgium), tidal marshes are restored on embanked land by allowing a controlled reduced tide (CRT) into a constructed basin, through a culvert in the embankment. In this way tidal water levels are significantly lowered (ca. 3 m) so that a CRT marsh can develop on formerly embanked land with a ca. 3 m lower elevation than the natural tidal marshes. In this study we compared the long-term change in elevation (ΔE) within a CRT marsh and adjacent natural tidal marsh. Over a period of 4 years, the observed spatio-temporal variations in ΔE rate were related to variations in inundation depth, and this relationship was not significantly different for the CRT marsh and natural tidal marsh. A model was developed to simulate the ΔE over the next century. (1) Under a scenario without mean high water level (MHWL) rise in the estuary, the model shows that the marsh elevation-ΔE feedback that is typical for a natural tidal marsh (i.e. rising marsh elevation results in decreasing inundation depth and therefore a decreasing increase in elevation) is absent in the basin of the CRT marsh. This is because tidal exchange of water volumes between the estuary and CRT marsh are independent from the CRT marsh elevation but dependent on the culvert dimensions. Thus the volume of water entering the CRT remains constant regardless of the marsh elevation. Consequently the CRT MHWL follows the increase in CRT surface elevation, resulting after 75 years in a 2–2.5 times larger elevation gain in the CRT marsh, and a faster reduction of spatial elevation differences. (2) Under a scenario of constant MHWL rise (historical rate of 1.5 cm a-1), the equilibrium elevation (relative to MHWL) is 0.13 m lower in the CRT marsh and is reached almost 2 times faster. (3) Under a scenario of

  11. Coastal salt-marshes in Albania

    OpenAIRE

    JULIAN SHEHU; ALMA IMERI; RUDINA KOCI; ALFRED MULLAJ

    2014-01-01

    The salt marshes of Albania comprise a narrow belt along the Adriatic and Ionian Seas. They have been the subject of a range of human activities causing habitat loss. Enclosure for agricultural use, ports and other infrastructure has reduced many salt marshes to a narrow fringe along estuary shores. Salt marshes are important for a range of interests. In particular they support a range of specialist plant communities and associated animals (especially breeding and wintering birds) and often h...

  12. Florida's salt-marsh management issues: 1991-98.

    Science.gov (United States)

    Carlson, D B; O'Bryan, P D; Rey, J R

    1999-06-01

    During the 1990s, Florida has continued to make important strides in managing salt marshes for both mosquito control and natural resource enhancement. The political mechanism for this progress continues to be interagency cooperation through the Florida Coordinating Council on Mosquito Control and its Subcommittee on Managed Marshes (SOMM). Continuing management experience and research has helped refine the most environmentally acceptable source reduction methods, which typically are Rotational Impoundment Management or Open Marsh Water Management. The development of regional marsh management plans for salt marshes within the Indian River Lagoon by the SOMM has helped direct the implementation of the best management practices for these marshes. Controversy occasionally occurs concerning what management technique is most appropriate for individual marshes. The most common disagreement is over the benefits of maintaining an impoundment in an "open" vs. "closed" condition, with the "closed" condition, allowing for summer mosquito control flooding or winter waterfowl management. New federal initiatives influencing salt-marsh management have included the Indian River Lagoon-National Estuary Program and the Pesticide Environmental Stewardship Program. A new Florida initiative is the Florida Department of Environmental Protection's Eco-system Management Program with continuing involvement by the Surface Water Improvement and Management program. A developing mitigation banking program has the potential to benefit marsh management but mosquito control interests may suffer if not handled properly. Larvicides remain as an important salt-marsh integrated pest management tool with the greatest acreage being treated with temephos, followed by Bacillus thuringiensis israelensis and methoprene. However, over the past 14 years, use of biorational larvicides has increased greatly.

  13. Dioxin in Midland: A Case Study of Press Coverage of Expert Disagreement.

    Science.gov (United States)

    Palen, John

    Drawing from articles appearing in several national publications about the dioxin contamination found in Midland, Michigan, in l983, a case study examined how the publications handled the phenomenon of expert disagreement concerning the nature of dioxin. Specifically, it examined how the publications handled expert disagreement about (1) the way…

  14. Safety evaluation report related to the operation of Midland Plant, Units 1 and 2. Docket Nos. 50-329 and 50-330, Consumers Power Company

    International Nuclear Information System (INIS)

    1982-05-01

    The Safety Evaluation Report for the application filed by the Consumers Power Company, as applicant and owner, for a license to operate the Midland Plant Units 1 and 2 (Docket Nos. 50-329 and 50-330), has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission. The facility is located near the city of Midland in Midland County, Michigan. Subject to favorable resolution of the items discussed in this report, the staff concludes that the facility can be operated by the applicant without endangering the health and safety of the public

  15. Effect of hurricanes and violent storms on salt marsh

    Science.gov (United States)

    Leonardi, N.; Ganju, N. K.; Fagherazzi, S.

    2016-12-01

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.

  16. Multispecies benefits of wetland conservation for marsh birds, frogs, and species at risk.

    Science.gov (United States)

    Tozer, Douglas C; Steele, Owen; Gloutney, Mark

    2018-04-15

    Wetlands conserved using water level manipulation, cattle exclusion, naturalization of uplands, and other techniques under the North American Waterfowl Management Plan ("conservation project wetlands") are important for ducks, geese, and swans ("waterfowl"). However, the assumption that conservation actions for waterfowl also benefit other wildlife is rarely quantified. We modeled detection and occupancy of species at sites within 42 conservation project wetlands compared to sites within 52 similar nearby unmanaged wetlands throughout southern Ontario, Canada, and small portions of the adjacent U.S., using citizen science data collected by Bird Studies Canada's Great Lakes Marsh Monitoring Program, including 2 waterfowl and 13 non-waterfowl marsh-breeding bird species (n = 413 sites) and 7 marsh-breeding frog species (n = 191 sites). Occupancy was significantly greater at conservation project sites compared to unmanaged sites in 7 of 15 (47%) bird species and 3 of 7 (43%) frog species, with occupancy being higher by a difference of 0.12-0.38 across species. Notably, occupancy of priority conservation concern or at-risk Black Tern (Chlidonias niger), Common Gallinule (Gallinula galeata), Least Bittern (Ixobrychus exilis), Sora (Porzana carolina), and Western Chorus Frog (Pseudacris triseriata) was significantly higher at conservation project sites compared to unmanaged sites. The results demonstrate the utility of citizen science to inform wetland conservation, and suggest that actions under the North American Waterfowl Management Plan are effective for conserving non-waterfowl species. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Structural Classification of Marshes with Polarimetric SAR Highlighting the Temporal Mapping of Marshes Exposed to Oil

    Directory of Open Access Journals (Sweden)

    Elijah Ramsey

    2015-09-01

    Full Text Available Empirical relationships between field-derived Leaf Area Index (LAI and Leaf Angle Distribution (LAD and polarimetric synthetic aperture radar (PolSAR based biophysical indicators were created and applied to map S. alterniflora marsh canopy structure. PolSAR and field data were collected near concurrently in the summers of 2010, 2011, and 2012 in coastal marshes, and PolSAR data alone were acquired in 2009. Regression analyses showed that LAI correspondence with the PolSAR biophysical indicator variables equaled or exceeded those of vegetation water content (VWC correspondences. In the final six regressor model, the ratio HV/VV explained 49% of the total 77% explained LAI variance, and the HH-VV coherence and phase information accounted for the remainder. HV/HH dominated the two regressor LAD relationship, and spatial heterogeneity and backscatter mechanism followed by coherence information dominated the final three regressor model that explained 74% of the LAD variance. Regression results applied to 2009 through 2012 PolSAR images showed substantial changes in marsh LAI and LAD. Although the direct cause was not substantiated, following a release of freshwater in response to the 2010 Deepwater Horizon oil spill, the fairly uniform interior marsh structure of 2009 was more vertical and dense shortly after the oil spill cessation. After 2010, marsh structure generally progressed back toward the 2009 uniformity; however, the trend was more disjointed in oil impact marshes.

  18. Flow paths of water and sediment in a tidal marsh: relations with marsh developmental stage and tidal inundation height

    NARCIS (Netherlands)

    Temmerman, S.; Bouma, T.J.; Govers, G.; Lauwaet, D.

    2005-01-01

    This study provides new insights in the relative role of tidal creeks and the marsh edge in supplying water and sediments to and from tidal marshes for a wide range of tidal inundation cycles with different high water levels and for marsh zones of different developmental stage. Net import or export

  19. Galveston Bay Marsh Terracing 2001-2002

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Marsh terracing is used to restore coastal wetlands by converting shallow nonvegetated bottom to intertidal marsh. Terraces are constructed from excavated bottom...

  20. Structural classification of marshes with Polarimetric SAR highlighting the temporal mapping of marshes exposed to oil

    Science.gov (United States)

    Ramsey, Elijah W.; Rangoonwala, Amina; Jones, Cathleen E.

    2015-01-01

    Empirical relationships between field-derived Leaf Area Index (LAI) and Leaf Angle Distribution (LAD) and polarimetric synthetic aperture radar (PolSAR) based biophysical indicators were created and applied to map S. alterniflora marsh canopy structure. PolSAR and field data were collected near concurrently in the summers of 2010, 2011, and 2012 in coastal marshes, and PolSAR data alone were acquired in 2009. Regression analyses showed that LAI correspondence with the PolSAR biophysical indicator variables equaled or exceeded those of vegetation water content (VWC) correspondences. In the final six regressor model, the ratio HV/VV explained 49% of the total 77% explained LAI variance, and the HH-VV coherence and phase information accounted for the remainder. HV/HH dominated the two regressor LAD relationship, and spatial heterogeneity and backscatter mechanism followed by coherence information dominated the final three regressor model that explained 74% of the LAD variance. Regression results applied to 2009 through 2012 PolSAR images showed substantial changes in marsh LAI and LAD. Although the direct cause was not substantiated, following a release of freshwater in response to the 2010 Deepwater Horizon oil spill, the fairly uniform interior marsh structure of 2009 was more vertical and dense shortly after the oil spill cessation. After 2010, marsh structure generally progressed back toward the 2009 uniformity; however, the trend was more disjointed in oil impact marshes.             

  1. Marshes on the Move: Testing effects of seawater intrusion on ...

    Science.gov (United States)

    The Northeastern United States is a hotspot for sea level rise (SLR), subjecting coastal salt marshes to erosive loss, shifts in vegetation communities, and altered biogeochemistry due to seawater intrusion. Salt marsh plant community zonation is driven by tradeoffs in stress tolerance and interspecific interactions. As seawater inundates progressively higher marsh elevations, shifts in marsh vegetation communities landward may herald salt marsh “migration”, which could allow continuity of marsh function and ecosystem service provision. To elucidate possible effects of seawater intrusion on marsh-upland edge plant communities, a space-for-time approach was replicated at two Rhode Island salt marshes. At each site, peat blocks (0.5 m x 0.5 m x 0.5 m, n=6) with intact upland-marsh edge vegetation were transplanted downslope into the regularly-inundated mid-marsh. Procedural controls (n=3) were established at each elevation by removing and replacing peat blocks, and natural controls (n=3) consisted of undisturbed plots. During peak productivity, each plot was assessed for species composition, percent cover and average height. Results demonstrate stunting of marsh-upland edge vegetation in response to increased inundation, and the beginnings of colonization of the transplanted plots by salt marsh species. The extent of colonization differed between the two sites, suggesting that site-specific factors govern vegetation responses to increased inundation.

  2. Modeling detection probability to improve marsh bird surveys in southern Canada and the Great Lakes states

    Directory of Open Access Journals (Sweden)

    Douglas C. Tozer

    2016-12-01

    Full Text Available Marsh birds are notoriously elusive, with variation in detection probability across species, regions, seasons, and different times of day and weather. Therefore, it is important to develop regional field survey protocols that maximize detections, but that also produce data for estimating and analytically adjusting for remaining differences in detections. We aimed to improve regional field survey protocols by estimating detection probability of eight elusive marsh bird species throughout two regions that have ongoing marsh bird monitoring programs: the southern Canadian Prairies (Prairie region and the southern portion of the Great Lakes basin and parts of southern Québec (Great Lakes-St. Lawrence region. We accomplished our goal using generalized binomial N-mixture models and data from ~22,300 marsh bird surveys conducted between 2008 and 2014 by Bird Studies Canada's Prairie, Great Lakes, and Québec Marsh Monitoring Programs. Across all species, on average, detection probability was highest in the Great Lakes-St. Lawrence region from the beginning of May until mid-June, and then fell throughout the remainder of the season until the end of June; was lowest in the Prairie region in mid-May and then increased throughout the remainder of the season until the end of June; was highest during darkness compared with light; and did not vary significantly according to temperature (range: 0-30°C, cloud cover (0%-100%, or wind (0-20 kph, or during morning versus evening. We used our results to formulate improved marsh bird survey protocols for each region. Our analysis and recommendations are useful and contribute to conservation of wetland birds at various scales from local single-species studies to the continental North American Marsh Bird Monitoring Program.

  3. Assessing the Potential for Inland Migration of a Northeastern Salt Marsh

    Science.gov (United States)

    Farron, S.; FitzGerald, D.; Hughes, Z. J.

    2017-12-01

    It is often assumed that as sea level rises, salt marshes will expand inland. If the slope of the upland is relatively flat and sufficient sediment is available, marshes should be able to spread horizontally and grow vertically in order to maintain their areal extent. However, in cases where marshes are backed by steeper slopes, or sediment supply is limited, rising sea level will produce minimal gains along the landward edge insufficient to offset potential losses along the seaward edge. This study uses future sea level rise scenarios to project areal losses for the Great Marsh in Massachusetts, the largest continuous salt marsh in New England. Land area covered by salt marsh is defined by surface elevation. Annual sediment input to the system is estimated based on the areal extent of high and low marsh, historical accretion rates for each, and known organic/inorganic ratios. Unlike other studies, sediment availability is considered to be finite, and future accretion rates are limited based on the assumption that the system is presently receiving the maximum sediment input available. The Great Marsh is dominated by high marsh; as sea level rises, it will convert to low marsh, vastly altering the ecological and sedimentological dynamics of the system. If it is assumed that former high marsh areas will build vertically at the increased rate associated with low marsh, then much of the total marsh area will be maintained. However, this may be an unrealistic assumption due to the low levels of suspended sediment within the Great Marsh system. Modeling the evolution of the Great Marsh by assuming that the current accretion rate is the maximum possible for this system reveals much greater losses than models assuming an unlimited sediment supply would predict (17% less marsh by 2115). In addition, uplands surrounding the Great Marsh have been shaped by glaciation, leaving numerous drumlins and other glacial landforms. Compared to the flat backbarrier, the surrounding

  4. Salt Marshes as Sources and Sinks of Silica

    Science.gov (United States)

    Carey, J.; Fulweiler, R. W.

    2014-12-01

    The role of salt marshes in controlling silica exchange between terrestrial and marine environments is unclear. In some studies, large quantities of dissolved silica (DSi) appear to be exported from marshes via tidal exchange, potentially fueling future diatom production in adjacent waters. In contrast, other studies report insignificant DSi export and found instead that salt marshes appeared to be Si sinks. Further, few studies examine salt marsh Si export in relation to inorganic nitrogen (DIN) and phosphorus (DIP). We address these uncertainties by quantifying net fluxes of DSi and biogenic Si (BSi), as well as DIN and DIP during the spring and summer in a relatively undisturbed southern New England salt marsh (Narragansett Bay, USA). Our data demonstrates that during the spring, when estuarine waters are deplete in DSi, the marsh serves as a net sink of BSi (132 mol h-1) and a source of DSi (31 mol h-1) to the estuary. The spring DIN:DSi ratios of ebbing water were more than five times lower than flood waters. Most importantly, the DSi export rates (6.5 x103 mol d-1 km-2) are an order of magnitude larger than the export by rivers in the region (115 mol d-1 km-2), indicating the marsh tidal exchange is vital in supplying the Si necessary for spring diatom blooms in the estuary. Conversely, during the summer the marsh served as a net Si sink, importing on average 59 mol DSi h-1 and 39 mol BSi h-1. These data highlight that the role of salt marshes in silica cycling appears to have a strong seasonality. We hypothesize that net import of Si increases the residence time of Si in estuarine systems, providing an important and previously over-looked ecosystem service. In the absence of salt marshes, ~5.1 x 104 kmol of Si would be exported from this system during the growing season, possibly decreasing Si availability and altering phytoplankton species composition in the estuary.

  5. East Midlands healthcare and bioscience sector strategy appendix 1: healthcare and bioscience res implementation plan

    OpenAIRE

    East Midlands Development Agency

    2007-01-01

    The healthcare and bioscience sector is one of four priority sectors identified in the regional economic strategy, A Flourishing Region. This document sets out the implementation plan for maximising the contribution of the healthcare and biosciences sector to the economic development of the East Midlands.

  6. Modelling Watershed and Estuarine Controls on Salt Marsh Distributions

    Science.gov (United States)

    Yousefi Lalimi, F.; Marani, M.; Murray, A. B.; D'Alpaos, A.

    2017-12-01

    The formation and evolution of tidal platforms have been extensively studied through observations and models, describing landform dynamics as a result of the local interactions and feedbacks among hydrodynamics, vegetation, and sediment transport. However, existing work mainly focuses on individual marsh platforms and, possibly, their immediate surrounding, such that the influence and controls on marsh dynamics of inland areas (through fluvial inputs) and of exchanges with the ocean have not been comprehensively and simultaneously accounted for. Here, we develop and use a process-based model to evaluate the relative role of watershed, estuarine, and ocean controls on salt marsh accretionary and depositional/erosional dynamics and define how these factors interact to determine salt marsh resilience to environmental change at the whole-estuary scale. Our results, in line with previous work, show that no stable equilibrium exists for the erosional dynamics of the marsh/tidal flat boundary. In addition, we find that under some circumstances, vertical accretion/erosion dynamics can lead to transitions between salt marsh and tidal flat equilibrium states that occur much more rapidly than marsh/tidal flat boundary erosion or accretion could. We further define, in the multidimensional space of estuarine-scale morphodynamic forcings, the basins of attractions leading to marsh-dominated and tidal-flat-dominated estuaries. The relatively slow dynamics asymptotically leading to marsh- or tidal-flat- dominance in many cases suggest that estuaries are likely to be found, at any given time, in a transition state dictated by temporal variations in environmental forcings.

  7. Tidal Marshes: The Boundary between Land and Ocean.

    Science.gov (United States)

    Gosselink, James

    An overview of the ecology of the tidal marshes along the gulf coast of the United States is presented. The following topics are included: (1) the human impact on tidal marshes; (2) the geologic origins of tidal marshes; (3) a description of the physical characteristics and ecosystem of the marshlands; (4) a description of the marshland food chain…

  8. Comparative Economics of Cattle and Wildlife Ranching in the Zimbabwe Midlands

    OpenAIRE

    Kreuter, Urs P.

    1992-01-01

    The economics of ranches in the Zimbabwe Midlands, generating income from cattle, or wildlife, or both, were compared during 1989/90 to test the claim that wildlife ranching can generate greater profits than cattle ranching on semi-arid African savannas. Both financial (market) prices and economic prices (opportunity cost) were used. Financial data were obtained from 15 cattle, 7 wildlife and 13 mixed ranches in four areas with wildlife and from 15 cattle ranches in two areas with sparse w...

  9. Biota - 2011 Vegetation Inventory - Marsh Lake, MN

    Data.gov (United States)

    Army Corps of Engineers, Department of the Army, Department of Defense — 2011 Vegetation Classification for Marsh Lake, MN Vegetation Project Report, OMBIL Environmental Stewardship - Level 1 Inventory. Marsh Lake is located on the...

  10. Carbon sequestration by Australian tidal marshes

    KAUST Repository

    Macreadie, Peter I.

    2017-03-10

    Australia\\'s tidal marshes have suffered significant losses but their recently recognised importance in CO2 sequestration is creating opportunities for their protection and restoration. We compiled all available data on soil organic carbon (OC) storage in Australia\\'s tidal marshes (323 cores). OC stocks in the surface 1 m averaged 165.41 (SE 6.96) Mg OC ha-1 (range 14-963 Mg OC ha-1). The mean OC accumulation rate was 0.55 ± 0.02 Mg OC ha-1 yr-1. Geomorphology was the most important predictor of OC stocks, with fluvial sites having twice the stock of OC as seaward sites. Australia\\'s 1.4 million hectares of tidal marshes contain an estimated 212 million tonnes of OC in the surface 1 m, with a potential CO2-equivalent value of $USD7.19 billion. Annual sequestration is 0.75 Tg OC yr-1, with a CO2-equivalent value of $USD28.02 million per annum. This study provides the most comprehensive estimates of tidal marsh blue carbon in Australia, and illustrates their importance in climate change mitigation and adaptation, acting as CO2 sinks and buffering the impacts of rising sea level. We outline potential further development of carbon offset schemes to restore the sequestration capacity and other ecosystem services provided by Australia tidal marshes.

  11. Dynamic interactions between coastal storms and salt marshes: A review

    Science.gov (United States)

    Leonardi, Nicoletta; Carnacina, Iacopo; Donatelli, Carmine; Ganju, Neil K.; Plater, Andrew James; Schuerch, Mark; Temmerman, Stijn

    2018-01-01

    This manuscript reviews the progresses made in the understanding of the dynamic interactions between coastal storms and salt marshes, including the dissipation of extreme water levels and wind waves across marsh surfaces, the geomorphic impact of storms on salt marshes, the preservation of hurricanes signals and deposits into the sedimentary records, and the importance of storms for the long term survival of salt marshes to sea level rise. A review of weaknesses, and strengths of coastal defences incorporating the use of salt marshes including natural, and hybrid infrastructures in comparison to standard built solutions is then presented.Salt marshes are effective in dissipating wave energy, and storm surges, especially when the marsh is highly elevated, and continuous. This buffering action reduces for storms lasting more than one day. Storm surge attenuation rates range from 1.7 to 25 cm/km depending on marsh and storms characteristics. In terms of vegetation properties, the more flexible stems tend to flatten during powerful storms, and to dissipate less energy but they are also more resilient to structural damage, and their flattening helps to protect the marsh surface from erosion, while stiff plants tend to break, and could increase the turbulence level and the scour. From a morphological point of view, salt marshes are generally able to withstand violent storms without collapsing, and violent storms are responsible for only a small portion of the long term marsh erosion.Our considerations highlight the necessity to focus on the indirect long term impact that large storms exerts on the whole marsh complex rather than on sole after-storm periods. The morphological consequences of storms, even if not dramatic, might in fact influence the response of the system to normal weather conditions during following inter-storm periods. For instance, storms can cause tidal flats deepening which in turn promotes wave energy propagation, and exerts a long term

  12. Dynamic interactions between coastal storms and salt marshes: A review

    Science.gov (United States)

    Leonardi, Nicoletta; Carnacina, Iacopo; Donatelli, Carmine; Ganju, Neil Kamal; Plater, Andrew James; Schuerch, Mark; Temmerman, Stijn

    2018-01-01

    This manuscript reviews the progresses made in the understanding of the dynamic interactions between coastal storms and salt marshes, including the dissipation of extreme water levels and wind waves across marsh surfaces, the geomorphic impact of storms on salt marshes, the preservation of hurricanes signals and deposits into the sedimentary records, and the importance of storms for the long term survival of salt marshes to sea level rise. A review of weaknesses, and strengths of coastal defences incorporating the use of salt marshes including natural, and hybrid infrastructures in comparison to standard built solutions is then presented. Salt marshes are effective in dissipating wave energy, and storm surges, especially when the marsh is highly elevated, and continuous. This buffering action reduces for storms lasting more than one day. Storm surge attenuation rates range from 1.7 to 25 cm/km depending on marsh and storms characteristics. In terms of vegetation properties, the more flexible stems tend to flatten during powerful storms, and to dissipate less energy but they are also more resilient to structural damage, and their flattening helps to protect the marsh surface from erosion, while stiff plants tend to break, and could increase the turbulence level and the scour. From a morphological point of view, salt marshes are generally able to withstand violent storms without collapsing, and violent storms are responsible for only a small portion of the long term marsh erosion. Our considerations highlight the necessity to focus on the indirect long term impact that large storms exerts on the whole marsh complex rather than on sole after-storm periods. The morphological consequences of storms, even if not dramatic, might in fact influence the response of the system to normal weather conditions during following inter-storm periods. For instance, storms can cause tidal flats deepening which in turn promotes wave energy propagation, and exerts a long term detrimental

  13. Exploring Management Strategies to Reduce Cheating in Written Examinations: Case Study of Midlands State University

    Science.gov (United States)

    Taderera, Ever; Nyikahadzoi, Loveness; Matamande, Wilson; Mandimika, Elinah

    2014-01-01

    This study was concerned about cheating in written examinations at Midlands State University (MSU). The study revealed that both male and female students cheat in written examination; business studies students cheat more than other faculties, and younger (lower class) students cheat more than (upper class) older students. Factors influencing…

  14. Seasonal comparison of aquatic macroinvertebrate assemblages in a flooded coastal freshwater marsh

    Science.gov (United States)

    Kang, Sung-Ryong; King, Sammy L.

    2013-01-01

    Marsh flooding and drying may be important factors affecting aquatic macroinvertebrate density and distribution in coastal freshwater marshes. Limited availability of water as a result of drying in emergent marsh may decrease density, taxonomic diversity, and taxa richness. The principal objectives of this study are to characterize the seasonal aquatic macroinvertebrate assemblage in a freshwater emergent marsh and compare aquatic macroinvertebrate species composition, density, and taxonomic diversity to that of freshwater marsh ponds. We hypothesize that 1) freshwater emergent marsh has lower seasonal density and taxonomic diversity compared to that of freshwater marsh ponds; and 2) freshwater emergent marsh has lower taxa richness than freshwater marsh ponds. Seasonal aquatic macroinvertebrate density in freshwater emergent marsh ranged from 0 organisms/m2 (summer 2009) to 91.1 ± 20.53 organisms/m2 (mean ± SE; spring 2009). Density in spring was higher than in all other seasons. Taxonomic diversity did not differ and there were no unique species in the freshwater emergent marsh. Our data only partially support our first hypothesis as aquatic macroinvertebrate density and taxonomic diversity between freshwater emergent marsh and ponds did not differ in spring, fall, and winter but ponds supported higher macroinvertebrate densities than freshwater emergent marsh during summer. However, our data did not support our second hypothesis as taxa richness between freshwater emergent marsh and ponds did not statistically differ.

  15. Estuaries and Tidal Marshes. Habitat Pac.

    Science.gov (United States)

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  16. Marshes on the Move: Testing effects of seawater intrusion on vegetation communities of the salt marsh-upland ecotone

    Science.gov (United States)

    The Northeastern United States is a hotspot for sea level rise (SLR), subjecting coastal salt marshes to erosive loss, shifts in vegetation communities, and altered biogeochemistry due to seawater intrusion. Salt marsh plant community zonation is driven by tradeoffs in stress to...

  17. Seismic and potential field studies over the East Midlands

    Science.gov (United States)

    Kirk, Wayne John

    A seismic refraction profile was undertaken to investigate the source of an aeromagnetic anomaly located above the Widmerpool Gulf, East Midlands. Ten shots were fired into 51 stations at c. 1.5km spacing in a 70km profile during 41 days recording. The refraction data were processed using standard techniques to improve the data quality. A new filtering technique, known as Correlated Adaptive Noise Cancellation was tested on synthetic data and successfully applied to controlled source and quarry blast data. Study of strong motion data reveals that the previous method of site calibration is invalid. A new calibration technique, known as the Scaled Amplitude method is presented to provide safer charge size estimation. Raytrace modelling of the refraction data and two dimensional gravity interpretation confirms the presence of the Widmerpool Gulf but no support is found for the postulated intrusion. Two dimensional magnetic interpretation revealed that the aeromagnetic anomaly could be modelled with a Carboniferous igneous source. A Lower Palaeozoic refractor with a velocity of 6.0 km/s is identified at a maximum depth of c. 2.85km beneath the Widmerpool Gulf. Carboniferous and post-Carboniferous sediments within the gulf have velocities between 2.6-5.5 km/s with a strong vertical gradient. At the gulf margins, a refractor with a constant velocity of 5.2 km/s is identified as Dinantian limestone. A low velocity layer of proposed unaltered Lower Palaeozoics is identified beneath the limestone at the eastern edge of the Derbyshire Dome. The existence and areal extent of this layer are also determined from seismic reflection data. Image analysis of potential field data, presents a model identifying 3 structural provinces, the Midlands Microcraton, the Welsh and English Caledonides and a central region of complex linears. This model is used to explain the distribution of basement rocks determined from seismic and gravity profiles.

  18. Final environmental statement related to the operation of Midland Plant, Units 1 and 2. Docket Nos. 50-329 and 50-330, Consumers Power Company

    International Nuclear Information System (INIS)

    1982-07-01

    This final environmental statement contains the second assessment of the environmental impact associated with operation of the Midland Plant, Units 1 and 2 pursuant to the National Environmental Policy Act of 1969 (NEPA) and 10 CFR Part 51, as amended, of the NRC's regulations. This statement examines: the purpose and need for the Midland project, alternatives to the project, the affected environment, environment consequences and mitigating actions, and environmental and economic benefits and costs

  19. Salt Marshes as Potential Indicatore of Global Climate Change

    DEFF Research Database (Denmark)

    Kim, Daehyun; Cairens, David; Jung, S.H.

    2011-01-01

    Coastal scientists postulate that salt marshes are significantly affected by dynamics of global climate. However, few studies have explicitly proposed a perspective that regards salt marshes as potential indicators of climate change. This review article evaluates the possibility of salt marshes...... as indicators of global climate change, focusing upon three major aspects: sedimentary, vegetation, and biogeochemical dynamics. The previous literature concerned with these aspects commonly argues that the primary impact of climate change on salt marshes occurs via sea-level variations, because hydrologic...... fluctuations regulate the frequency, duration, and depth of over-marsh flooding events. Sedimentary, floristic, and biogeochemical dynamics prove to be significantly influenced by sealevel changes regardless of climate zones, and hence, undoubtedly possess a potential for indicating climate signatures. However...

  20. Can salt marshes survive sea level rise ?

    Science.gov (United States)

    Tambroni, N.; Seminara, G.

    2008-12-01

    Stability of salt marshes is a very delicate issue depending on the subtle interplay among hydrodynamics, morphodynamics and ecology. In fact, the elevation of the marsh platform depends essentially on three effects: i) the production of soil associated with sediments resuspended by tidal currents and wind waves in the adjacent tidal flats, advected to the marsh and settling therein; ii) production of organic sediments by the salt marsh vegetation; iii) soil 'loss' driven by sea level rise and subsidence. In order to gain insight into the mechanics of the process, we consider a schematic configuration consisting of a salt marsh located at the landward end of a tidal channel connected at the upstream end with a tidal sea, under different scenarios of sea level rise. We extend the simple 1D model for the morphodynamic evolution of a tidal channel formulated by Lanzoni and Seminara (2002, Journal of Geophysical Research-Oceans, 107, C1) allowing for sediment resuspension in the channel and vegetation growth in the marsh using the depth dependent model of biomass productivity of Spartina proposed by Morris et al. (2002, Ecology, 83, pp. 2869 - 2877). We first focus on the case of a tide dominated salt marsh neglecting wind driven sediment resuspension in the shoal. Results show that the production of biomass plays a crucial role on salt marsh stability and, provided productivity is high enough, it may turn out to be sufficient to counteract the effects of sea level rise even in the absence of significant supply of mineral sediments. The additional effect of wind resuspension is then introduced. Note that the wind action is twofold: on one hand, it generates wind waves the amplitude of which is strongly dependent on shoal depth and wind fetch; on the other hand, it generates currents driven by the surface setup induced by the shear stress acting on the free surface. Here, each contribution is analysed separately. Results show that the values of bottom stress induced by

  1. Assessing Salt Marsh Recovery Utilizing Improved Computer-Aided Tomography Technology (CTT)

    Science.gov (United States)

    In 2001 the Padanarum marsh, a small 7.2-acre marsh in Dartmouth, MA, was chosen as a Tidal Hydrology Restoration site. The site was initially characterized as a brackish mostly freshwater deteriorating marsh. In May 2003 the seawater input to this marsh was increased by replacin...

  2. PARTICIPATION MOTIVATION IN MARTIAL ARTISTS IN THE WEST MIDLANDS REGION OF ENGLAND

    Directory of Open Access Journals (Sweden)

    Derek M. Peters

    2006-07-01

    Full Text Available The objectives were to identify the participation motivations and the perceived importance of certain participation factors in martial artists in the West Midlands, England, UK. A 28-item adapted version of the Participation Motivation Questionnaire with additional demographic questions was distributed to 30 martial arts clubs in the West Midlands region. Eight questions that assessed the perceived importance for participation of progression through grades, learning self defence skills, technical ability of instructors, cost of participating, development of confidence, underpinning philosophy and instructional style were included. Seventy-five questionnaires were returned from a total of 11 clubs from across representing practitioners in Tai Chi, Karate, Kung fu, Aikido, Jeet Kune Do, British Free Fighting, Taekwon-Do and Jujitsu. Results indicated that the rank order in terms of participation motives was: 1-Affiliation; 2-Friendship; 3-Fitness; 4-Reward/status; 5-Competition; 6-Situational and 7-Skill development. Participants who trained for more than 4 hours per week placed greater importance on the underpinning philosophy of the martial art. Findings suggest that whilst there is a gender discrepancy in participation level, once engaged, females were equally committed to weekly training. The 'style' of the instructor is of paramount importance for enhancing student motivation to participate. High volume practitioners would appear to be fully immersed in the holistic appreciation of the martial art through increased value placed on its underpinning philosophy

  3. Hydrodynamic Modeling of Santa Marta's Big Marsh

    International Nuclear Information System (INIS)

    Saldarriaga, Juan

    1991-01-01

    The ecological degradation of Santa Marta's Big Marsh and their next areas it has motivated the realization of diagnosis studies and design by several state and private entities. One of the recommended efforts for international advisory it was to develop an ecological model that allowed the handling of the water body and the economic test of alternative of solution to those ecological problems. The first part of a model of this type is in turn a model that simulates the movement of the water inside the marsh, that is to say, a hydrodynamic model. The realization of this was taken charge to the civil engineering department, on the part of Colciencias. This article contains a general explanation of the hydrodynamic pattern that this being developed by a professors group. The ecological causes are described and antecedent, the parts that conform the complex of the Santa Marta big Marsh The marsh modeling is made and it is explained in qualitative form the model type Hydrodynamic used

  4. Unsupervised detection of salt marsh platforms: a topographic method

    Science.gov (United States)

    Goodwin, Guillaume C. H.; Mudd, Simon M.; Clubb, Fiona J.

    2018-03-01

    Salt marshes filter pollutants, protect coastlines against storm surges, and sequester carbon, yet are under threat from sea level rise and anthropogenic modification. The sustained existence of the salt marsh ecosystem depends on the topographic evolution of marsh platforms. Quantifying marsh platform topography is vital for improving the management of these valuable landscapes. The determination of platform boundaries currently relies on supervised classification methods requiring near-infrared data to detect vegetation, or demands labour-intensive field surveys and digitisation. We propose a novel, unsupervised method to reproducibly isolate salt marsh scarps and platforms from a digital elevation model (DEM), referred to as Topographic Identification of Platforms (TIP). Field observations and numerical models show that salt marshes mature into subhorizontal platforms delineated by subvertical scarps. Based on this premise, we identify scarps as lines of local maxima on a slope raster, then fill landmasses from the scarps upward, thus isolating mature marsh platforms. We test the TIP method using lidar-derived DEMs from six salt marshes in England with varying tidal ranges and geometries, for which topographic platforms were manually isolated from tidal flats. Agreement between manual and unsupervised classification exceeds 94 % for DEM resolutions of 1 m, with all but one site maintaining an accuracy superior to 90 % for resolutions up to 3 m. For resolutions of 1 m, platforms detected with the TIP method are comparable in surface area to digitised platforms and have similar elevation distributions. We also find that our method allows for the accurate detection of local block failures as small as 3 times the DEM resolution. Detailed inspection reveals that although tidal creeks were digitised as part of the marsh platform, unsupervised classification categorises them as part of the tidal flat, causing an increase in false negatives and overall platform

  5. Unsupervised detection of salt marsh platforms: a topographic method

    Directory of Open Access Journals (Sweden)

    G. C. H. Goodwin

    2018-03-01

    Full Text Available Salt marshes filter pollutants, protect coastlines against storm surges, and sequester carbon, yet are under threat from sea level rise and anthropogenic modification. The sustained existence of the salt marsh ecosystem depends on the topographic evolution of marsh platforms. Quantifying marsh platform topography is vital for improving the management of these valuable landscapes. The determination of platform boundaries currently relies on supervised classification methods requiring near-infrared data to detect vegetation, or demands labour-intensive field surveys and digitisation. We propose a novel, unsupervised method to reproducibly isolate salt marsh scarps and platforms from a digital elevation model (DEM, referred to as Topographic Identification of Platforms (TIP. Field observations and numerical models show that salt marshes mature into subhorizontal platforms delineated by subvertical scarps. Based on this premise, we identify scarps as lines of local maxima on a slope raster, then fill landmasses from the scarps upward, thus isolating mature marsh platforms. We test the TIP method using lidar-derived DEMs from six salt marshes in England with varying tidal ranges and geometries, for which topographic platforms were manually isolated from tidal flats. Agreement between manual and unsupervised classification exceeds 94 % for DEM resolutions of 1 m, with all but one site maintaining an accuracy superior to 90 % for resolutions up to 3 m. For resolutions of 1 m, platforms detected with the TIP method are comparable in surface area to digitised platforms and have similar elevation distributions. We also find that our method allows for the accurate detection of local block failures as small as 3 times the DEM resolution. Detailed inspection reveals that although tidal creeks were digitised as part of the marsh platform, unsupervised classification categorises them as part of the tidal flat, causing an increase in false negatives

  6. Salt Marsh Formation in the Lower Hudson River Estuary

    Science.gov (United States)

    Merley, Michael; Peteet, Dorothy; Hansen, James E. (Technical Monitor)

    2001-01-01

    Salt marshes are constant depositional environments and as a result contain accurate indicators of past relative sea level rise and salinity. The Hudson River marshes are at least twice as deep when compared to coastal marshes on either side of the mouth of the Hudson. The reason for this difference in sedimentation is unclear. This study uses macrofossil data as well as sediment stratigraphy in order to understand the formation and evolution of these marshes. The composition of seeds, roots, shoots and foraminifera, are used to indicate past sea levels. The four sites involved in this study are, from south to north, the Arthur Kill Marsh in Staten Island (40 36 N, 74 77W), Piermont marsh (N 4100; 73 55W) Croton Point (41 14 N; 73 50W) and Iona Island (41 18N, 73 58W). These are all tidally influenced but with increasing distances from the New York Bight, which gives a good spectrum of tidal influence. AMS-C14 dates on basal macrofossils will document the time of each marsh formation. Basal material from Arthur Kill (8 m) includes freshwater seeds such as Viola, Potomageton and Alnus along with Salix buds. Basal material from Croton Point (10 m) includes fibrous woody material, foraminifera and Zanichellia seeds and other brackish vegetational components. The basal material from Piermont (13.77 m) is lacking any identifiable macrofossils between 150 and 500 microns. The basal material from Iona Island (10 m) has vegetation such as Scirpus and Cyperus seeds, probably implying a brackish environment. The freshwater origin of the Arthur Kill marsh in Staten Island is significant because it predates either sea level rise or the western channel incision. Additional implications for this study include evidence for changes in river channel geomorphology. Reasons for the relatively deeper river marshes include possible basal clay compaction, high production due to river and marine nutrients as well as tectonic activity. This study provides the groundwork for more high

  7. Modelling the long-term vertical dynamics of salt marshes

    Science.gov (United States)

    Zoccarato, Claudia; Teatini, Pietro

    2017-04-01

    Salt marshes are vulnerable environments hosting complex interactions between physical and biological processes with a strong influence on the dynamics of the marsh evolution. The estimation and prediction of the elevation of a salt-marsh platform is crucial to forecast the marsh growth or regression under different scenarios considering, for example, the potential climate changes. The long-term vertical dynamics of a salt marsh is predicted with the aid of an original finite-element (FE) numerical model accounting for the marsh accretion and compaction and for the variation rates of the relative sea level rise, i.e., land subsidence of the marsh basement and eustatic rise of the sea level. The accretion term considers the vertical sedimentation of organic and inorganic material over the marsh surface, whereas the compaction reflects the progressive consolidation of the porous medium under the increasing load of the overlying younger deposits. The modelling approach is based on a 2D groundwater flow simulator, which provides the pressure evolution within a compacting/accreting vertical cross-section of the marsh assuming that the groundwater flow obeys the relative Darcy's law, coupled to a 1D vertical geomechanical module following Terzaghi's principle of effective intergranular stress. Soil porosity, permeability, and compressibility may vary with the effective intergranular stress according to empirically based relationships. The model also takes into account the geometric non-linearity arising from the consideration of large solid grain movements by using a Lagrangian approach with an adaptive FE mesh. The element geometry changes in time to follow the deposit consolidation and the element number increases in time to follow the sedimentation of new material. The numerical model is tested on different realistic configurations considering the influence of (i) the spatial distribution of the sedimentation rate in relation to the distance from the marsh margin, (ii

  8. Annual and seasonal distribution of intertidal foraminifera and stable carbon isotope geochemistry, Bandon Marsh, Oregon, USA

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin; Vane, Christopher; Engelhart, Simon; Nelson, Alan R.; Witter, Robert C.; Khan, Nicole S.; Bridgeland, William

    2014-01-01

    We investigated the influence of inter-annual and seasonal differences on the distribution of live and dead foraminifera, and the inter-annual variability of stable carbon isotopes (d13C), total organic carbon (TOC) values and carbon to nitrogen (C/N) ratios in bulk sediments from intertidal environments of Bandon Marsh (Oregon, USA). Living and dead foraminiferal species from 10 stations were analyzed over two successive years in the summer (dry) and fall (wet) seasons. There were insignificant inter-annual and seasonal variations in the distribution of live and dead species. But there was a noticeable decrease in calcareous assemblages (Haynesina sp.) between live populations and dead assemblages, indicating that most of the calcareous tests were dissolved after burial; the agglutinated assemblages were comparable between constituents. The live populations and dead assemblages were dominated by Miliammina fusca in the tidal flat and low marsh, Jadammina macrescens, Trochammina inflata and M. fusca in the high marsh, and Trochamminita irregularis and Balticammina pseudomacrescens in the highest marsh to upland. Geochemical analyses (d13C, TOC and C/N of bulk sedimentary organic matter) show no significant influence of inter-annual variations but a significant correlation of d13C values (R = 20.820, p , 0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R = 0.885, p , 0.001) to elevation with respect to the tidal frame. Our results suggest that foraminiferal assemblages and d13C and TOC values, as well as C/N ratios, in Bandon Marsh are useful in reconstructing paleosea-levels on the North American Pacific coast.

  9. Estuaries as filters: the role of tidal marshes in trace metal removal.

    Directory of Open Access Journals (Sweden)

    Johannes Teuchies

    Full Text Available Flux calculations demonstrate that many estuaries are natural filters for trace metals. Yet, the underlying processes are poorly investigated. In the present study, it was hypothesized that intertidal marshes contribute significantly to the contaminant filter function of estuaries. Trace metal concentrations and sediment characteristics were measured along a transect from the subtidal, over an intertidal flat and marsh to a restored marsh with controlled reduced tide. Metal concentrations in the intertidal and restored marsh were found to be a factor two to five higher than values in the subtidal and intertidal flat sediments. High metal concentrations and high accretion rates indicate a high metal accumulation capacity of the intertidal marshes. Overbank sedimentation in the tidal marshes of the entire estuary was calculated to remove 25% to 50% of the riverine metal influx, even though marshes comprise less than 8% of the total surface of the estuary. In addition, the large-scale implementation of planned tidal marsh restoration projects was estimated to almost double the trace metal storage capacity of the present natural tidal marshes in the estuary.

  10. Estuaries as Filters: The Role of Tidal Marshes in Trace Metal Removal

    Science.gov (United States)

    Teuchies, Johannes; Vandenbruwaene, Wouter; Carpentier, Roos; Bervoets, Lieven; Temmerman, Stijn; Wang, Chen; Maris, Tom; Cox, Tom J. S.; Van Braeckel, Alexander; Meire, Patrick

    2013-01-01

    Flux calculations demonstrate that many estuaries are natural filters for trace metals. Yet, the underlying processes are poorly investigated. In the present study, it was hypothesized that intertidal marshes contribute significantly to the contaminant filter function of estuaries. Trace metal concentrations and sediment characteristics were measured along a transect from the subtidal, over an intertidal flat and marsh to a restored marsh with controlled reduced tide. Metal concentrations in the intertidal and restored marsh were found to be a factor two to five higher than values in the subtidal and intertidal flat sediments. High metal concentrations and high accretion rates indicate a high metal accumulation capacity of the intertidal marshes. Overbank sedimentation in the tidal marshes of the entire estuary was calculated to remove 25% to 50% of the riverine metal influx, even though marshes comprise less than 8% of the total surface of the estuary. In addition, the large-scale implementation of planned tidal marsh restoration projects was estimated to almost double the trace metal storage capacity of the present natural tidal marshes in the estuary. PMID:23950927

  11. Fracture toughness evaluation of a low upper-shelf weld metal from the Midland Reactor using the master curve

    International Nuclear Information System (INIS)

    McCabe, D.E.; Sokolov, M.A.; Nanstad, R.K.

    1997-01-01

    The primary objective of the Heavy-Section Steel Irradiation (HSSI) Program Tenth Irradiation Series was to develop a fracture mechanics evaluation of weld metal WF-70, which was taken from the beltline and nozzle course girth weld joints of the Midland Reactor vessel. This material became available when Consumers Power Company of Midland, Michigan, decided to abort plans to operate their nuclear power plant. WF-70 is classified as a low upper-shelf steel primarily due to the Linde 80 flux that was used in the submerged-arc welding process. The master curve concept is introduced to model the transition range fracture toughness when the toughness is quantified in terms of K Jc values. K Jc is an elastic-plastic stress intensity factor calculated by conversion from J c ; i.e., J-integral at onset of cleavage instability

  12. Marsh collapse thresholds for coastal Louisiana estimated using elevation and vegetation index data

    Science.gov (United States)

    Couvillion, Brady R.; Beck, Holly

    2013-01-01

    Forecasting marsh collapse in coastal Louisiana as a result of changes in sea-level rise, subsidence, and accretion deficits necessitates an understanding of thresholds beyond which inundation stress impedes marsh survival. The variability in thresholds at which different marsh types cease to occur (i.e., marsh collapse) is not well understood. We utilized remotely sensed imagery, field data, and elevation data to help gain insight into the relationships between vegetation health and inundation. A Normalized Difference Vegetation Index (NDVI) dataset was calculated using remotely sensed data at peak biomass (August) and used as a proxy for vegetation health and productivity. Statistics were calculated for NDVI values by marsh type for intermediate, brackish, and saline marsh in coastal Louisiana. Marsh-type specific NDVI values of 1.5 and 2 standard deviations below the mean were used as upper and lower limits to identify conditions indicative of collapse. As marshes seldom occur beyond these values, they are believed to represent a range within which marsh collapse is likely to occur. Inundation depth was selected as the primary candidate for evaluation of marsh collapse thresholds. Elevation relative to mean water level (MWL) was calculated by subtracting MWL from an elevation dataset compiled from multiple data types including light detection and ranging (lidar) and bathymetry. A polynomial cubic regression was used to examine a random subset of pixels to determine the relationship between elevation (relative to MWL) and NDVI. The marsh collapse uncertainty range values were found by locating the intercept of the regression line with the 1.5 and 2 standard deviations below the mean NDVI value for each marsh type. Results indicate marsh collapse uncertainty ranges of 30.7–35.8 cm below MWL for intermediate marsh, 20–25.6 cm below MWL for brackish marsh, and 16.9–23.5 cm below MWL for saline marsh. These values are thought to represent the ranges of

  13. Balanced Sediment Fluxes in Southern California's Mediterranean-climate Zone Salt Marshes

    Science.gov (United States)

    Rosencranz, J. A.; Dickhudt, P.; Ganju, N. K.; Thorne, K.; Takekawa, J.; Ambrose, R. F.; Guntenspergen, G. R.; Brosnahan, S.; MacDonald, G. M.

    2015-12-01

    Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many southern California, USA salt marshes import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are also potentially important for marsh stability. We calculated tidal creek sediment fluxes within a sediment starved 1.5 km2 salt marsh (Seal Beach) and a less modified 1 km2 marsh (Mugu) with a watershed sediment supply. We measured salt marsh plain suspended sediment concentration and vertical accretion using single stage samplers and marker horizons. At Seal Beach, a 2014 storm yielded 39 and 28 g/s mean sediment fluxes and imported 12000 and 8800 kg in a western channel. This offset 8700 kg export during two months of dry weather, while landward net fluxes in the eastern channel accounted for 33% of the import. During the storm, suspended sediment concentrations on the marsh plain increased by a factor of four; accretion was 1-2 mm near creek levees. An exceptionally high tide sequence at Mugu yielded 4.4 g/s mean sediment flux, importing 1700 kg, accounting for 20% of dry weather fluxes. Overall, low sediment fluxes were observed, suggesting that these salt marshes are currently geomorphically stable. Our results suggest that storms and exceptionally high lunar tides may play large roles, importing sediment and maintaining dry weather sediment flux balances for southern California salt marshes. However, under future climate change and sea-level rise scenarios, results suggest that balanced sediment fluxes may lead to marsh elevational instability, based on estimated mineral sediment deficits.

  14. Marsh canopy structure changes and the Deepwater Horizon oil spill

    Science.gov (United States)

    Ramsey, Elijah W.; Rangoonwala, Amina; Jones, Cathleen E.

    2016-01-01

    Marsh canopy structure was mapped yearly from 2009 to 2012 in the Barataria Bay, Louisiana coastal region that was impacted by the 2010 Deepwater Horizon (DWH) oil spill. Based on the previously demonstrated capability of NASA's UAVSAR polarimetric synthetic aperture radar (PolSAR) image data to map Spartina alterniflora marsh canopy structure, structure maps combining the leaf area index (LAI) and leaf angle distribution (LAD, orientation) were constructed for yearly intervals that were directly relatable to the 2010 LAI-LAD classification. The yearly LAI-LAD and LAI difference maps were used to investigate causes for the previously revealed dramatic change in marsh structure from prespill (2009) to postspill (2010, spill cessation), and the occurrence of structure features that exhibited abnormal spatial and temporal patterns. Water level and salinity records showed that freshwater releases used to keep the oil offshore did not cause the rapid growth from 2009 to 2010 in marsh surrounding the inner Bay. Photointerpretation of optical image data determined that interior marsh patches exhibiting rapid change were caused by burns and burn recovery, and that the pattern of 2010 to 2011 LAI decreases in backshore marsh and extending along some tidal channels into the interior marsh were not associated with burns. Instead, the majority of 2010 to 2011 shoreline features aligned with vectors displaying the severity of 2010 shoreline oiling from the DWH spill. Although the association is not conclusive of a causal oil impact, the coexistent pattern is a significant discovery. PolSAR marsh structure mapping provided a unique perspective of marsh biophysical status that enhanced detection of change and monitoring of trends important to management effectiveness.

  15. Loss of 'blue carbon' from coastal salt marshes following habitat disturbance.

    Directory of Open Access Journals (Sweden)

    Peter I Macreadie

    Full Text Available Increased recognition of the global importance of salt marshes as 'blue carbon' (C sinks has led to concern that salt marshes could release large amounts of stored C into the atmosphere (as CO2 if they continue undergoing disturbance, thereby accelerating climate change. Empirical evidence of C release following salt marsh habitat loss due to disturbance is rare, yet such information is essential for inclusion of salt marshes in greenhouse gas emission reduction and offset schemes. Here we investigated the stability of salt marsh (Spartinaalterniflora sediment C levels following seagrass (Thallasiatestudinum wrack accumulation; a form of disturbance common throughout the world that removes large areas of plant biomass in salt marshes. At our study site (St Joseph Bay, Florida, USA, we recorded 296 patches (7.5 ± 2.3 m(2 mean area ± SE of vegetation loss (aged 3-12 months in a salt marsh meadow the size of a soccer field (7 275 m(2. Within these disturbed patches, levels of organic C in the subsurface zone (1-5 cm depth were ~30% lower than the surrounding undisturbed meadow. Subsequent analyses showed that the decline in subsurface C levels in disturbed patches was due to loss of below-ground plant (salt marsh biomass, which otherwise forms the main component of the long-term 'refractory' C stock. We conclude that disturbance to salt marsh habitat due to wrack accumulation can cause significant release of below-ground C; which could shift salt marshes from C sinks to C sources, depending on the intensity and scale of disturbance. This mechanism of C release is likely to increase in the future due to sea level rise; which could increase wrack production due to increasing storminess, and will facilitate delivery of wrack into salt marsh zones due to higher and more frequent inundation.

  16. Delineation of marsh types and marsh-type change in coastal Louisiana for 2007 and 2013

    Science.gov (United States)

    Hartley, Stephen B.; Couvillion, Brady R.; Enwright, Nicholas M.

    2017-05-30

    The Bureau of Ocean Energy Management researchers often require detailed information regarding emergent marsh vegetation types (such as fresh, intermediate, brackish, and saline) for modeling habitat capacities and mitigation. In response, the U.S. Geological Survey in cooperation with the Bureau of Ocean Energy Management produced a detailed change classification of emergent marsh vegetation types in coastal Louisiana from 2007 and 2013. This study incorporates two existing vegetation surveys and independent variables such as Landsat Thematic Mapper multispectral satellite imagery, high-resolution airborne imagery from 2007 and 2013, bare-earth digital elevation models based on airborne light detection and ranging, alternative contemporary land-cover classifications, and other spatially explicit variables. An image classification based on image objects was created from 2007 and 2013 National Agriculture Imagery Program color-infrared aerial photography. The final products consisted of two 10-meter raster datasets. Each image object from the 2007 and 2013 spatial datasets was assigned a vegetation classification by using a simple majority filter. In addition to those spatial datasets, we also conducted a change analysis between the datasets to produce a 10-meter change raster product. This analysis identified how much change has taken place and where change has occurred. The spatial data products show dynamic areas where marsh loss is occurring or where marsh type is changing. This information can be used to assist and advance conservation efforts for priority natural resources.

  17. Assessing wildlife benefits and carbon storage from restored and natural coastal marshes in the Nisqually River Delta: Determining marsh net ecosystem carbon balance

    Science.gov (United States)

    Anderson, Frank; Bergamaschi, Brian; Windham-Myers, Lisamarie; Woo, Isa; De La Cruz, Susan; Drexler, Judith; Byrd, Kristin; Thorne, Karen M.

    2016-06-24

    Working in partnership since 1996, the U.S. Fish and Wildlife Service and the Nisqually Indian Tribe have restored 902 acres of tidally influenced coastal marsh in the Nisqually River Delta (NRD), making it the largest estuary-restoration project in the Pacific Northwest to date. Marsh restoration increases the capacity of the estuary to support a diversity of wildlife species. Restoration also increases carbon (C) production of marsh plant communities that support food webs for wildlife and can help mitigate climate change through long-term C storage in marsh soils.In 2015, an interdisciplinary team of U.S. Geological Survey (USGS) researchers began to study the benefits of carbon for wetland wildlife and storage in the NRD. Our primary goals are (1) to identify the relative importance of the different carbon sources that support juvenile chinook (Oncorhynchus tshawytscha) food webs and contribute to current and historic peat formation, (2) to determine the net ecosystem carbon balance (NECB) in a reference marsh and a restoration marsh site, and (3) to model the sustainability of the reference and restoration marshes under projected sea-level rise conditions along with historical vegetation change. In this fact sheet, we focus on the main C sources and exchanges to determine NECB, including carbon dioxide (CO2) uptake through plant photosynthesis, the loss of CO2 through plant and soil respiration, emissions of methane (CH4), and the lateral movement or leaching loss of C in tidal waters.

  18. Tidal Marshes as Pulsing Systems: New Estimates of Marsh-Carbon Export and Fate

    Science.gov (United States)

    Logozzo, L. A.; Neale, P.; Tzortziou, M.; Nelson, N.; Megonigal, P.

    2016-02-01

    We investigated wetland-estuarine exchanges of dissolved organic carbon (DOC), chromophoric dissolved organic matter (CDOM), dissolved inorganic carbon (DIC), and chlorophyll a (chl a) in the Chesapeake Bay Kirkpatrick wetlands, an ecosystem that is representative of brackish marshes with organic-rich soils in North America. 1 L water samples were collected every hour over multiple semidiurnal tidal cycles (24 h deployments) and the flow was continuously measured every minute over the course of the study. DIC samples were collected and filtered on site. Fluxes were estimated using the measured flow and concentrations of biogeochemical variables (DOC, DIC, and chl a as a measure of algal biomass). aCDOM(300) was used as a proxy for CDOM amount to observe variations over two semidiurnal tidal cycles. Relative to high tide water, low tide water was consistently enriched in DOC, DIC, and CDOM, whereas it was consistently depleted in chl a. Initial estimates of fluxes over the tidal cycle showed net export of DIC and DOC from the marsh, and net import of chl a into the marsh. These results are consistent with DOC flux estimates from previous studies, but our method utilizes high temporal resolution flow measurements, improving flux estimate accuracy. Transect sampling from the marsh into the sub-estuary during ebbing tide indicated a strong negative gradient in a­CDOM­(300) and non-conservative mixing with salinity. The observed gradients in CDOM absorption spectral shape (slope and slope ratios) and the relative changes in the major fluorescence components identified in 3D fluorescence excitation-emission-matrices, indicated strong photochemical degradation in the estuary and a shift from higher to lower molecular-weight organic compounds. The weaker gradients observed for DOC and DIC compared to aCDOM(300) indicate that while microbial degradation does occur, photobleaching is the dominant degradation mechanism for CDOM in the estuary.

  19. Salt Marsh Ecosystem Responses to Restored Tidal Connectivity across a 14y Chronosequence

    Science.gov (United States)

    Capooci, M.; Spivak, A. C.; Gosselin, K.

    2016-02-01

    Salt marshes support valuable ecosystem services. Yet, human activities negatively impact salt marsh function and contribute to their loss at a global scale. On Cape Cod, MA, culverts and impoundments under roads and railways restricted tidal exchange and resulted in salt marsh conversion to freshwater wetlands. Over the past 14 y, these structures have been removed or replaced, restoring tidal connectivity between marshes and a saltwater bay. We evaluated differences in plant community composition, sediment properties, and pore water chemistry in marshes where tidal connectivity was restored using a space-for-time, or chronosequence approach. Each restored marsh was paired with a nearby, natural salt marsh to control for variability between marshes. In each restored and natural salt marsh we evaluated the plant community by measuring species-specific percent cover and biomass and collected sediment cores for bulk density and pore water analyses. Plant communities responded rapidly: salt-tolerant species, such as Spartina alterniflora, became established while freshwater species, including Phragmites australis, were less abundant within 3 y of restoration. The number of plant species was generally greater in marshes restored within 10 y, compared to older and natural marshes. Sediment bulk density varied with depth and across sites. This likely reflects differences in site history and local conditions. Deeper horizons (24-30cm) generally had higher values in restored sites while surface values (0-3cm) were similar in restored and natural marshes. Porewater pH and sulfide were similar in restored and natural marshes, suggesting rapid microbial responses to seawater reintroduction. Overall, marsh properties and processes reflecting biological communities responded rapidly to tidal restoration. However, variability between study locations underscores the potential importance of site history, local hydrology, and geomorphology in shaping marsh biogeochemistry.

  20. Climate change and sustainability of the carbon sink in Maritime salt marshes

    International Nuclear Information System (INIS)

    Chmura, G.L.

    2008-01-01

    Ideal carbon sinks do not emit greenhouse gases (GHGs) and are sustainable with future trends in global warming. This presentation discussed the potential for using Maritime salt marshes as carbon sinks. The marshes are covered with grasses adapted to saline soils. Photosynthesis by the marsh plants and algae fix the carbon dioxide (CO 2 ) directly from the atmosphere. The carbon is then buried by mineral sediment. Wetlands without saline water are known to produce methane. The carbon in salt marsh soils does not significantly decline with depth or time. Salt marshes and mangroves store an average of 210 g of CO 2 per m 2 per year. The tidal floodwaters keep the soils wet, which allows for slow decomposition. Canadian salt marsh soils have increased in thickness at a rate of between 2 to 4 mm per year. Measurement programs have demonstrated the sustainability of inner Bay of Fundy marshes in relation to rising sea levels. Opportunities for carbon sinks also exist in dyked marshes in the region. It was concluded that the salt marshes can account for between 4 to 6 per cent of Canada's targeted reductions under the Kyoto Protocol. tabs., figs.

  1. Influence of call broadcast timing within point counts and survey duration on detection probability of marsh breeding birds

    Directory of Open Access Journals (Sweden)

    Douglas C. Tozer

    2017-12-01

    Full Text Available The Standardized North American Marsh Bird Monitoring Protocol recommends point counts consisting of a 5-min passive observation period, meant to be free of broadcast bias, followed by call broadcasts to entice elusive species to reveal their presence. Prior to this protocol, some monitoring programs used point counts with broadcasts during the first 5 min of 10-min counts, and have since used 15-min counts with an initial 5-min passive period (P1 followed by 5 min of broadcasts (B and a second 5-min passive period (P2 to ensure consistency across years and programs. Influence of timing of broadcasts within point counts and point count duration, however, have rarely been assessed. Using data from 23,973 broadcast-assisted 15-min point counts conducted throughout the Great Lakes-St. Lawrence region between 2008 and 2016 by Bird Studies Canada's Marsh Monitoring Program and Central Michigan University's Great Lakes Coastal Wetland Monitoring Program, we estimated detection probabilities of individuals for 14 marsh breeding bird species during P1B compared to BP2, P1 compared to P2, and P1B compared to P1BP2. For six broadcast species and American Bittern (Botaurus lentiginosus, we found no significant difference in detection during P1B compared to BP2, and no significant difference in four of the same seven species during P1 compared to P2. We observed small but significant differences in detection for 7 of 14 species during P1B compared to P1BP2. We conclude that differences in timing of broadcasts causes no bias based on counts from entire 10-minute surveys, although P1B should be favored over BP2 because the same amount of effort in P1B avoids broadcast bias in all broadcast species, and 10-min surveys are superior to 15-min surveys because modest gains in detection of some species does not warrant the additional effort. We recommend point counts consisting of 5 min of passive observation followed by broadcasts, consistent with the standardized

  2. Herbivory drives the spread of salt marsh die-off.

    Directory of Open Access Journals (Sweden)

    Mark D Bertness

    Full Text Available Salt marsh die-off is a Western Atlantic conservation problem that has recently spread into Narragansett Bay, Rhode Island, USA. It has been hypothesized to be driven by: 1 eutrophication decreasing plant investment into belowground biomass causing plant collapse, 2 boat wakes eroding creek banks, 3 pollution or disease affecting plant health, 4 substrate hardness controlling herbivorous crab distributions and 5 trophic dysfunction releasing herbivorous crabs from predator control. To distinguish between these hypotheses we quantified these variables at 14 Narragansett Bay salt marshes where die-off intensity ranged from <5% to nearly 98%. Nitrogen availability, wave intensity and plant growth did not explain any variation in die-off. Herbivory explained 73% of inter-site variation in die-off and predator control of herbivores and substrate hardness also varied significantly with die-off. This suggests that salt marsh die-off is being largely driven by intense herbivory via the release of herbivorous crabs from predator control. Our results and those from other marsh systems suggest that consumer control may not simply be a factor to consider in marsh conservation, but with widespread predator depletion impacting near shore habitats globally, trophic dysfunction and runaway consumption may be the largest and most urgent management challenge for salt marsh conservation.

  3. Carbon Sequestration in Tidal Salt Marshes of the Northeast United States.

    Science.gov (United States)

    Drake, Katherine; Halifax, Holly; Adamowicz, Susan C; Craft, Christopher

    2015-10-01

    Tidal salt marshes provide important ecological services, habitat, disturbance regulation, water quality improvement, and biodiversity, as well as accumulation and sequestration of carbon dioxide (CO2) in vegetation and soil organic matter. Different management practices may alter their capacity to provide these ecosystem services. We examined soil properties (bulk density, percent organic C, percent N), C and N pools, C sequestration and N accumulation at four marshes managed with open marsh water management (OMWM) and four marshes that were not at U.S. Fish and Wildlife National Wildlife Refuges (NWRs) on the East Coast of the United States. Soil properties (bulk density, percent organic C, percent N) exhibited no consistent differences among managed and non-OMWM marshes. Soil organic carbon pools (0-60-cm depth) also did not differ. Managed marshes contained 15.9 kg C/m(2) compared to 16.2 kg C/m(2) in non-OMWM marshes. Proportionately, more C (per unit volume) was stored in surface than in subsurface soils. The rate of C sequestration, based on (137)Cs and (210)Pb dating of soil cores, ranged from 41 to 152 g/m(2)/year. Because of the low emissions of CH4 from salt marshes relative to freshwater wetlands and the ability to sequester C in soil, protection and restoration of salt marshes can be a vital tool for delivering key ecosystem services, while at the same time, reducing the C footprint associated with managing these wetlands.

  4. Salt marsh persistence is threatened by predicted sea-level rise

    Science.gov (United States)

    Crosby, Sarah C.; Sax, Dov F.; Palmer, Megan E.; Booth, Harriet S.; Deegan, Linda A.; Bertness, Mark D.; Leslie, Heather M.

    2016-11-01

    Salt marshes buffer coastlines and provide critical ecosystem services from storm protection to food provision. Worldwide, these ecosystems are in danger of disappearing if they cannot increase elevation at rates that match sea-level rise. However, the magnitude of loss to be expected is not known. A synthesis of existing records of salt marsh elevation change was conducted in order to consider the likelihood of their future persistence. This analysis indicates that many salt marshes did not keep pace with sea-level rise in the past century and kept pace even less well over the past two decades. Salt marshes experiencing higher local sea-level rise rates were less likely to be keeping pace. These results suggest that sea-level rise will overwhelm most salt marshes' capacity to maintain elevation. Under the most optimistic IPCC emissions pathway, 60% of the salt marshes studied will be gaining elevation at a rate insufficient to keep pace with sea-level rise by 2100. Without mitigation of greenhouse gas emissions this potential loss could exceed 90%, which will have substantial ecological, economic, and human health consequences.

  5. The protective role of coastal marshes: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Christine C Shepard

    Full Text Available BACKGROUND: Salt marshes lie between many human communities and the coast and have been presumed to protect these communities from coastal hazards by providing important ecosystem services. However, previous characterizations of these ecosystem services have typically been based on a small number of historical studies, and the consistency and extent to which marshes provide these services has not been investigated. Here, we review the current evidence for the specific processes of wave attenuation, shoreline stabilization and floodwater attenuation to determine if and under what conditions salt marshes offer these coastal protection services. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a thorough search and synthesis of the literature with reference to these processes. Seventy-five publications met our selection criteria, and we conducted meta-analyses for publications with sufficient data available for quantitative analysis. We found that combined across all studies (n = 7, salt marsh vegetation had a significant positive effect on wave attenuation as measured by reductions in wave height per unit distance across marsh vegetation. Salt marsh vegetation also had a significant positive effect on shoreline stabilization as measured by accretion, lateral erosion reduction, and marsh surface elevation change (n = 30. Salt marsh characteristics that were positively correlated to both wave attenuation and shoreline stabilization were vegetation density, biomass production, and marsh size. Although we could not find studies quantitatively evaluating floodwater attenuation within salt marshes, there are several studies noting the negative effects of wetland alteration on water quantity regulation within coastal areas. CONCLUSIONS/SIGNIFICANCE: Our results show that salt marshes have value for coastal hazard mitigation and climate change adaptation. Because we do not yet fully understand the magnitude of this value, we propose that decision

  6. Tidal flushing restores the physiological condition of fish residing in degraded salt marshes.

    Directory of Open Access Journals (Sweden)

    Kimberly L Dibble

    Full Text Available Roads, bridges, and dikes constructed across salt marshes can restrict tidal flow, degrade habitat quality for nekton, and facilitate invasion by non-native plants including Phragmites australis. Introduced P. australis contributes to marsh accretion and eliminates marsh surface pools thereby adversely affecting fish by reducing access to intertidal habitats essential for feeding, reproduction, and refuge. Our study assessed the condition of resident fish populations (Fundulus heteroclitus at four tidally restricted and four tidally restored marshes in New England invaded by P. australis relative to adjacent reference salt marshes. We used physiological and morphological indicators of fish condition, including proximate body composition (% lipid, % lean dry, % water, recent daily growth rate, age class distributions, parasite prevalence, female gravidity status, length-weight regressions, and a common morphological indicator (Fulton's K to assess impacts to fish health. We detected a significant increase in the quantity of parasites infecting fish in tidally restricted marshes but not in those where tidal flow was restored to reduce P. australis cover. Using fish length as a covariate, we found that unparasitized, non-gravid F. heteroclitus in tidally restricted marshes had significantly reduced lipid reserves and increased lean dry (structural mass relative to fish residing in reference marshes. Fish in tidally restored marshes were equivalent across all metrics relative to those in reference marshes indicating that habitat quality was restored via increased tidal flushing. Reference marshes adjacent to tidally restored sites contained the highest abundance of young fish (ages 0-1 while tidally restricted marshes contained the lowest. Results indicate that F. heteroclitus residing in physically and hydrologically altered marshes are at a disadvantage relative to fish in reference marshes but the effects can be reversed through ecological

  7. Signatures of Biogeomorphic Feedbacks in Salt-Marsh Systems

    Science.gov (United States)

    D'Alpaos, Andrea; Marani, Marco

    2015-04-01

    Salt-marsh ecosystems which play a large role in the bio-geomorphological evolution of intertidal areas. Dense stands of halophytic vegetations which populate salt marshes largely control the dynamics of these ecosystems influencing marsh hydrodynamics and sediment transport through enhanced flow resistance and settling, and direct particle capture by plant stems. Moreover, plants are also known to increase vertical accretion through direct organic accretion. Field evidence and the results of biomorphodynamic models indeed show that the interplay between physical and biological processes generates some striking biological and morphological patterns at different scales. One such pattern, vegetation zonation, consists in a mosaic of vegetation patches, of approximately uniform composition, displaying sharp transitions in the presence of extremely small topographic gradients. Here we develop a two-dimensional model which describes the mutual interaction and adjustment between tidal flows, sediment transport and morphology mediated by vegetation influence. The model allows us describe the coupled evolution of marsh platforms and channel networks cutting through them. A number of different scenarios were modelled to analyze the changes induced in bio-geomorphic patterns by plants with different characteristics, within marshes characterized by different drainage densities, or subjected to changing environmental forcing such as rates of relative sea level rise and sediment supply. Model results emphasize that zonation patterns are a signature of bio-geomorphic feedbacks with vegetation acting as a landscape constructor which feeds back on, directly alters, and contributes to shape tidal environments. In addition, model results show that biogeomorphic feedbacks critically affect the response and the resilience of salt-marsh landscapes to changes in the environmental forcing.

  8. Estimating patterns in Spartina alterniflora belowground biomass within salt marshes

    Science.gov (United States)

    O'Connell, J. L.; Mishra, D. R.; Alber, M.; Byrd, K. B.

    2017-12-01

    Belowground biomass of marsh plants, such as Spartina alterniflora, help prevent marsh loss because they promote soil accretion, stabilize soils and add organic matter. However, site-wide estimates of belowground biomass are difficult to obtain because root:shoot ratios vary considerably both within species and across sites. We are working to develop a data fusion tool that can predict key characteristics of S. alterniflora, including belowground biomass and plant canopy N, based on satellite imagery. We used field observations from four salt marsh locations along the Georgia Coast, including one that is studied as part of the Georgia Coastal Ecosystems LTER project. From field and remote-sensing data, we developed a hybrid modeling approach to estimate % foliar N (a surrogate for plant assimilated nutrients). Partial Least squares (PLS) regression analysis of Landsat-8 spectral bands could predict variation in foliar N and belowground biomass, suggesting this public data source might be utilized for site-wide assessment of plant biophysical variables in salt marshes. Spectrally estimated foliar N and aboveground biomass were associated with belowground biomass and root:shoot ratio in S. alterniflora. This mirrors results from a previous study from the Sacramento-San Joaquin Delta, CA, on Scheonoplectus acutus, a marsh plant found in some tidal freshwater marshes. Therefore remote sensing may be a useful tool for measuring whole plant productivity among multiple coastal marsh species.

  9. Assessing biomass of diverse coastal marsh ecosystems using statistical and machine learning models

    Science.gov (United States)

    Mo, Yu; Kearney, Michael S.; Riter, J. C. Alexis; Zhao, Feng; Tilley, David R.

    2018-06-01

    The importance and vulnerability of coastal marshes necessitate effective ways to closely monitor them. Optical remote sensing is a powerful tool for this task, yet its application to diverse coastal marsh ecosystems consisting of different marsh types is limited. This study samples spectral and biophysical data from freshwater, intermediate, brackish, and saline marshes in Louisiana, and develops statistical and machine learning models to assess the marshes' biomass with combined ground, airborne, and spaceborne remote sensing data. It is found that linear models derived from NDVI and EVI are most favorable for assessing Leaf Area Index (LAI) using multispectral data (R2 = 0.7 and 0.67, respectively), and the random forest models are most useful in retrieving LAI and Aboveground Green Biomass (AGB) using hyperspectral data (R2 = 0.91 and 0.84, respectively). It is also found that marsh type and plant species significantly impact the linear model development (P biomass of Louisiana's coastal marshes using various optical remote sensing techniques, and highlights the impacts of the marshes' species composition on the model development and the sensors' spatial resolution on biomass mapping, thereby providing useful tools for monitoring the biomass of coastal marshes in Louisiana and diverse coastal marsh ecosystems elsewhere.

  10. A coupled geomorphic and ecological model of tidal marsh evolution.

    Science.gov (United States)

    Kirwan, Matthew L; Murray, A Brad

    2007-04-10

    The evolution of tidal marsh platforms and interwoven channel networks cannot be addressed without treating the two-way interactions that link biological and physical processes. We have developed a 3D model of tidal marsh accretion and channel network development that couples physical sediment transport processes with vegetation biomass productivity. Tidal flow tends to cause erosion, whereas vegetation biomass, a function of bed surface depth below high tide, influences the rate of sediment deposition and slope-driven transport processes such as creek bank slumping. With a steady, moderate rise in sea level, the model builds a marsh platform and channel network with accretion rates everywhere equal to the rate of sea-level rise, meaning water depths and biological productivity remain temporally constant. An increase in the rate of sea-level rise, or a reduction in sediment supply, causes marsh-surface depths, biomass productivity, and deposition rates to increase while simultaneously causing the channel network to expand. Vegetation on the marsh platform can promote a metastable equilibrium where the platform maintains elevation relative to a rapidly rising sea level, although disturbance to vegetation could cause irreversible loss of marsh habitat.

  11. Nutrient cycling in salt marshes: An ecosystem service to reduce eutrophication

    DEFF Research Database (Denmark)

    Lillebø, A. I.; Sousa, A. I.; Flindt, M. R.

    2013-01-01

    and sequestration in salt marshes. This chapter will thus emphasise that salt marsh halophytes have a crucial role on nutrient cycling and sequestration, providing ecological services that contribute to maintain the ecosystem health. © 2012 Nova Science Publishers, Inc. All rights reserved.......Salt marshes are classified as sensitive habitat under the Habitats Directive (92/43/EEC), which aims to promote the maintenance of biodiversity. Worldwide, the reduction of salt marsh areas, as a result of anthropogenic disturbance is of major concern, and several studies on the ecology...

  12. Inorganic Carbon and Oxygen Dynamics in a Marsh-dominated Estuary

    Science.gov (United States)

    Wang, S. R.; Di Iorio, D.; Cai, W. J.; Hopkinson, C.

    2017-12-01

    A free-water mass balance-based study was conducted to address the rate of metabolism and net carbon exchange for the tidal wetland and estuarine portion of the coastal ocean and the uncertainties associated with this approach were assessed. Open water diurnal O2 and dissolved inorganic carbon (DIC) were measured seasonally in a salt marsh-estuary in Georgia, U.S.A. with a focus on the marsh-estuary linkage associated with tidal flooding. We observed that the overall estuarine system was a net source of CO2 to the atmosphere and coastal ocean and a net sink for oceanic and atmospheric O2. Rates of metabolism were extremely high, with respiration (43 mol m-2 yr-1) greatly exceeding gross primary production (28 mol m-2 yr-1), such that the overall system was net heterotrophic. Metabolism measured with DIC were higher than with O2, which we attribute to high rates of anaerobic respiration and reduced sulfur storage in salt marsh sediments, and we assume substantial levels of anoxygenic photosynthesis. We found gas exchange from a flooded marsh is substantial, accounting for about 28% of total O2 and CO2 air-water exchange. A significant percentage of the overall estuarine aquatic metabolism is attributable to metabolism of marsh organisms during inundation. Our study suggests not rely on oceanographic stoichiometry to convert from O2to C based measurements when constructing C balances for the coastal ocean. We also suggest eddy covariance measurements of salt marsh net ecosystem exchange underestimate net ecosystem production as they do not account for lateral DIC exchange associated with marsh tidal inundation. With the increase of global temperature and sea level rise, salt marshes are likely to export more inorganic carbon to the atmosphere and the coastal ocean due to the decrease of solubility, the increase of aquatic and benthic metabolic activities and the longer marsh inundation.

  13. Tidal marsh susceptibility to sea-level rise: importance of local-scale models

    Science.gov (United States)

    Thorne, Karen M.; Buffington, Kevin J.; Elliott-Fisk, Deborah L.; Takekawa, John Y.

    2015-01-01

    Increasing concern over sea-level rise impacts to coastal tidal marsh ecosystems has led to modeling efforts to anticipate outcomes for resource management decision making. Few studies on the Pacific coast of North America have modeled sea-level rise marsh susceptibility at a scale relevant to local wildlife populations and plant communities. Here, we use a novel approach in developing an empirical sea-level rise ecological response model that can be applied to key management questions. Calculated elevation change over 13 y for a 324-ha portion of San Pablo Bay National Wildlife Refuge, California, USA, was used to represent local accretion and subsidence processes. Next, we coupled detailed plant community and elevation surveys with measured rates of inundation frequency to model marsh state changes to 2100. By grouping plant communities into low, mid, and high marsh habitats, we were able to assess wildlife species vulnerability and to better understand outcomes for habitat resiliency. Starting study-site conditions were comprised of 78% (253-ha) high marsh, 7% (30-ha) mid marsh, and 4% (18-ha) low marsh habitats, dominated by pickleweed Sarcocornia pacifica and cordgrass Spartina spp. Only under the low sea-level rise scenario (44 cm by 2100) did our models show persistence of some marsh habitats to 2100, with the area dominated by low marsh habitats. Under mid (93 cm by 2100) and high sea-level rise scenarios (166 cm by 2100), most mid and high marsh habitat was lost by 2070, with only 15% (65 ha) remaining, and a complete loss of these habitats by 2080. Low marsh habitat increased temporarily under all three sea-level rise scenarios, with the peak (286 ha) in 2070, adding habitat for the endemic endangered California Ridgway’s rail Rallus obsoletus obsoletus. Under mid and high sea-level rise scenarios, an almost complete conversion to mudflat occurred, with most of the area below mean sea level. Our modeling assumed no marsh migration upslope due to human

  14. 78 FR 15714 - Welch Motel, Inc., Welch Oil, Inc., Boondocks USA Truck Stop, Bob Welch v. Midland Power...

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    2013-03-12

    ..., Inc., Welch Oil, Inc., Boondocks USA Truck Stop, Bob Welch v. Midland Power Cooperative, Corn Belt..., Welch Motel, Inc., Welch Oil, Inc., Boondocks USA Truck Stop, and Bob Welch (collectively, Complainants... into a contract to consume all of the electric energy and capacity generated by [[Page 15715...

  15. 76 FR 28019 - Gregory R. Swecker, Beverly F. Swecker v. Midland Power Cooperative, State of Iowa; Notice of...

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    2011-05-13

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. EL11-39-000] Gregory R. Swecker, Beverly F. Swecker v. Midland Power Cooperative, State of Iowa; Notice of Complaint Take notice... 1978 (PURPA),\\1\\ Gregory R. Swecker and Beverly F. Swecker (Complainants) filed a petition requesting...

  16. Regeneration of coastal marsh vegetation impacted by hurricanes Katrina and Rita

    Science.gov (United States)

    Middleton, B.A.

    2009-01-01

    The dynamics of plant regeneration via seed and vegetative spread in coastal wetlands dictate the nature of community reassembly that takes place after hurricanes or sea level rise. The objectives of my project were to evaluate the potential effects of saltwater intrusion and flooding of Hurricanes Katrina and Rita on seedling regeneration in coastal wetlands of the Gulf Coast. Specifically I tested hypotheses to determine for species in fresh, brackish and salt marshes of the Gulf Coast if 1) the pattern of seed germination and seedling recruitment differed with distance from the shoreline, and 2) seed germination and seedling recruitment for various species were reduced in higher levels of water depth and salinity. Regarding Hypothesis 1, seedling densities increased with distance from the shoreline in fresh and brackish water marshes while decreasing with distance from the shoreline in salt marshes. Also to test Hypothesis 1, I used a greenhouse seed bank assay to examine seed germination from seed banks collected at distances from the shoreline in response to various water depths and salinity levels using a nested factorial design. For all marsh types, the influence of water level and salinity on seed germination shifted with distance from the shoreline (i.e., three way interaction of the main effects of distance nested within site, water depth, and salinity). Data from the seed bank assay were also used to test Hypothesis 2. The regeneration of species from fresh, brackish, and salt marshes were reduced in conditions of high salinity and/or water, so that following hurricanes or sea level rise, seedling regeneration could be reduced. Among the species of these coastal marshes, there was some flexibility of response, so that at least some species were able to germinate in either high or low salinity. Salt marshes had a few fresher marsh species in the seed bank that would not germinate without a period of fresh water input (e.g., Sagittaria lancifolia) as well

  17. Salt-Marsh Landscapes and the Signatures of Biogeomorphic Feedbacks

    Science.gov (United States)

    D'Alpaos, A.; Marani, M.

    2014-12-01

    Salt marshes are coastal ecosystems which play a large role in the bio-geomorphological evolution of intertidal areas. The dense stands of halophytic plants which populate salt-marsh systems largely contribute to govern their dynamics, influencing marsh hydrodynamics and sediment transport through enhanced flow resistance and settling, and direct particle capture by plant stems. In addition, plants are known to increase vertical accretion through direct organic accretion. Looking across the salt-marsh landscape can one see the signatures of feedbacks between landscape and biota? Field evidence and the results of biomorphodynamic models indeed show that the interplay between physical and biological processes generates some striking biological and morphological patterns at different scales. One such pattern, vegetation zonation, consists in a mosaic of vegetation patches, of approximately uniform composition, displaying sharp transitions in the presence of extremely small topographic gradients. Here we extend the model proposed by Marani et al. (2013) to a two-dimensional framework, furthermore including the effect of direct capture of sediment particles by plant stems. This allows us to account for the effect of the drainage density of tidal networks on the observed biogeomorphic patterns and to model the coupled evolution of marsh platforms and channel networks cutting through them. A number of different scenarios have been modelled to analyze the changes induced in bio-geomorphic patterns by plants with different characteristics, within marshes characterized by different drainage densities, or subjected to changing environmental forcing such as rates of relative sea level rise and sediment supply. Model results emphasize that zonation patterns are a signature of bio-geomorphic feedbacks with vegetation acting as a landscape constructor which feeds back on, directly alters, and contributes to shape tidal environments. In addition, model results show that

  18. Balanced sediment fluxes in southern California’s Mediterranean-climate zone salt marshes

    Science.gov (United States)

    Rosencranz, Jordan A.; Ganju, Neil K.; Ambrose, Richard F.; Brosnahan, Sandra M.; Dickhudt, Patrick J.; Guntenspergen, Glenn R.; MacDonald, Glen M.; Takekawa, John Y.; Thorne, Karen M.

    2016-01-01

    Salt marsh elevation and geomorphic stability depends on mineral sedimentation. Many Mediterranean-climate salt marshes along southern California, USA coast import sediment during El Niño storm events, but sediment fluxes and mechanisms during dry weather are potentially important for marsh stability. We calculated tidal creek sediment fluxes within a highly modified, sediment-starved, 1.5-km2 salt marsh (Seal Beach) and a less modified 1-km2marsh (Mugu) with fluvial sediment supply. We measured salt marsh plain suspended sediment concentration and vertical accretion using single stage samplers and marker horizons. At Seal Beach, a 2014 storm yielded 39 and 28 g/s mean sediment fluxes and imported 12,000 and 8800 kg in a western and eastern channel. Western channel storm imports offset 8700 kg exported during 2 months of dry weather, while eastern channel storm imports augmented 9200 kg imported during dry weather. During the storm at Mugu, suspended sediment concentrations on the marsh plain increased by a factor of four; accretion was 1–2 mm near creek levees. An exceptionally high tide sequence yielded 4.4 g/s mean sediment flux, importing 1700 kg: 20 % of Mugu’s dry weather fluxes. Overall, low sediment fluxes were observed, suggesting that these salt marshes are geomorphically stable during dry weather conditions. Results suggest storms and high lunar tides may play large roles, importing sediment and maintaining dry weather sediment flux balances for southern California salt marshes. However, under future climate change and sea level rise scenarios, results suggest that balanced sediment fluxes lead to marsh elevational instability based on estimated mineral sediment deficits.

  19. Accretion rates in salt marshes in the Eastern Scheldt, South-west Netherlands

    International Nuclear Information System (INIS)

    Oenema, O.; DeLaune, R.D.

    1988-01-01

    Vertical accretion and sediment accumulation rates were determined from the distribution of 137 Cs in sediment cores, from historic documents, and from artificial white-coloured tracer layers in salt marshes in the Eastern Scheldt. Salt marsh accretion is related to the steady rise of the mean high tide in the Eastern Scheldt during the last few decades. Mean accretion rates vary from 0.4-0.9 cm year -1 in the St Annaland marsh to 1.0-1.5 cm year -1 in the Rattekaai marsh. Sediment accumulation in accreting marshes exceed the loss of sediment, by retreat of the marsh cliffs, by a factor of 10-20. Short-term spatial and temporal variations in accretion rates are large. Spatial variations are associated with levee and backmarsh sites and the density of marsh vegetation. Temporal variations are mainly related to fluctuations in hydrodynamic conditions. The net vertical accretion rate of organic carbon is 0.4 ± 0.1 kg m -2 year -1 , approximately half this rate is associated with the current deposit, and the other half with net additions from the belowground root biomass. A simple model for the root biomass distribution of Spartina anglica with depth and the depth-dependent fossilization of root biomass in sediments of the Rattekaai marsh is presented. (author)

  20. Rural women's perspectives of maternity services in the Midland Region of New Zealand.

    Science.gov (United States)

    Gibbons, Veronique; Lancaster, Gytha; Gosman, Kim; Lawrenson, Ross

    2016-09-01

    INTRODUCTION Rural women face many challenges with regards to maternity services. Many rural primary birthing facilities in New Zealand have closed. The Lead Maternity Carer (LMC) model of maternity care, introduced in 1990, has moved provision of rural maternity care from doctors to independent midwifery services. Shortages of rural midwives in the Midland region led to rural maternity care being seen as a vulnerable service. AIM To understand the views and experiences of rural women concerning maternity care, to inform the future design and provision of rural maternity services. METHODS Participants were drawn from areas purposively selected to represent the five District Health Boards comprising the Midland health region. A demographic questionnaire, focus groups and individual interviews explored rural women's perspectives of antenatal care provision. These were analysed thematically. RESULTS Sixty-two women were recruited. Key themes emerging from focus groups and interviews included: access to services, the importance of safety and quality of care, the need for appropriate information at different stages, and the role of partners, family and friends in the birthing journey. While most women were happy with access to services, quality of care, provision of information, and the role of family in their care, for some women, this experience could be enhanced. CONCLUSION Midwives are the frontline service for women seeking antenatal services. Support for rural midwives and for local birthing units is needed to ensure rural women receive services equal to that of their urban counterparts.

  1. Nitrous oxide emissions could reduce the blue carbon value of marshes on eutrophic estuaries

    Science.gov (United States)

    Roughan, Brittney L.; Kellman, Lisa; Smith, Erin; Chmura, Gail L.

    2018-04-01

    The supply of nitrogen to ecosystems has surpassed the Earth’s Planetary Boundary and its input to the marine environment has caused estuarine waters to become eutrophic. Excessive supply of nitrogen to salt marshes has been associated with shifts in species’ distribution and production, as well as marsh degradation and loss. Our study of salt marshes in agriculturally intensive watersheds shows that coastal eutrophication can have an additional impact. We measured gas fluxes from marsh soils and verified emissions of nitrous oxide (N2O) in nitrogen-loaded marshes while the reference marsh was a sink for this gas. Salt marsh soils are extremely efficient carbon sinks, but emissions of N2O, a greenhouse gas 298 times more potent than CO2, reduces the value of the carbon sink, and in some marshes, may counterbalance any value of stored carbon towards mitigation of climate change. Although more research is merited on the nitrogen transformations and carbon storage in eutrophic marshes, the possibility of significant N2O emissions should be considered when evaluating the market value of carbon in salt marshes subject to high levels of nitrogen loading.

  2. Halophyte vegetation influences in salt marsh retention capacity for heavy metals

    International Nuclear Information System (INIS)

    Reboreda, Rosa; Cacador, Isabel

    2007-01-01

    We analysed concentrations of Cu, Cd and Pb in above and belowground tissues of the halophyte species Halimione portulacoides and Spartina maritima, as well as in sediments and pore water between the roots in a Tagus estuary salt marsh (Portugal). From these results we calculated the pools of metals in the compartments mentioned above. Relative percentages of accumulation in each pool were also determined. Our aim was to determine how the type of vegetation in the salt marsh affects overall metal retention capacity of the system. It was concluded that areas colonised by H. portulacoides are potential sources of Cu, Cd and Pb to the marsh ecosystem, whereas areas colonised by S. maritima are more effective sinks at least for Cu and Cd. Consequently, S. maritima seems to contribute more effectively to the stabilisation of metals in salt marsh sediments, reducing their availability to the estuarine system. - The type of vegetal cover can affect the overall retention capacity of a salt marsh as well as the functioning of the salt marsh as a sink or source of metals to the estuarine system

  3. Tidal salt marshes of the southeast Atlantic Coast: A community profile

    Energy Technology Data Exchange (ETDEWEB)

    Wiegert, R.G.; Freeman, B.J.

    1990-09-01

    This report is part of a series of community profiles on the ecology of wetland and marine communities. This particular profile considers tidal marshes of the southeastern Atlantic coast, from North Carolina south to northern Florida. Alone among the earth's ecosystems, coastal communities are subjected to a bidirectional flooding sometimes occurring twice each day; this flooding affects successional development, species composition, stability, and productivity. In the tidally influenced salt marsh, salinity ranges from less than 1 ppt to that of seawater. Dominant plant species include cordgrasses (Spartina alterniflora and S. cynosuroides), black needlerush (Juncus romerianus), and salt marsh bulrush (Scirpus robustus). Both terrestrail and aquatic animals occur in salt marshes and include herons, egrets ospreys (Pandion haliaetus), bald eagles (Haliaeetus leucocephalus), alligators (Alligator Mississippiensis), manatees (Trichecus manatus), oysters, mussels, and fiddler crabs. Currently, the only significant direct commercial use of the tidal salt marshes is by crabbers seeking the blue crab Callinectes sapidus, but the marshes are quite important recreationally, aesthetically, and educationally. 151 refs., 45 figs., 6 tabs.

  4. Biogenic silica in tidal freshwater marsh sediments and vegetation (Schelde estuary, Belgium)

    NARCIS (Netherlands)

    Struyf, E.; van Damme, S.; Gribsholt, B.; Middelburg, J.J.; Meire, P.

    2005-01-01

    To date, estuarine ecosystem research has mostly neglected silica cycling in freshwater intertidal marshes. However, tidal marshes can store large amounts of biogenic silica (BSi) in vegetation and sediment. BSi content of the typical freshwater marsh plants Phragmites australis, Impatiens

  5. A geographically-restricted but prevalent Mycobacterium tuberculosis strain identified in the West Midlands Region of the UK between 1995 and 2008.

    Directory of Open Access Journals (Sweden)

    Jason T Evans

    2011-03-01

    Full Text Available We describe the identification of, and risk factors for, the single most prevalent Mycobacterium tuberculosis strain in the West Midlands region of the UK.Prospective 15-locus MIRU-VNTR genotyping of all M. tuberculosis isolates in the West Midlands between 2004 and 2008 was undertaken. Two retrospective epidemiological investigations were also undertaken using univariable and multivariable logistic regression analysis. The first study of all TB patients in the West Midlands between 2004 and 2008 identified a single prevalent strain in each of the study years (total 155/3,056 (5% isolates. This prevalent MIRU-VNTR profile (32333 2432515314 434443183 remained clustered after typing with an additional 9-loci MIRU-VNTR and spoligotyping. The majority of these patients (122/155, 79% resided in three major cities located within a 40 km radius. From the apparent geographical restriction, we have named this the "Mercian" strain. A multivariate analysis of all TB patients in the West Midlands identified that infection with a Mercian strain was significantly associated with being UK-born (OR =  9.03, 95%CI = 4.56-17.87, p65 years old (OR = 0.25, 95% CI = 0.09-0.67, p < 0.01. A second more detailed investigation analyzed a cohort of 82 patients resident in Wolverhampton between 2003 and 2006. A significant association with being born in the UK remained after a multivariate analysis (OR = 9.68, 95% CI = 2.00-46.78, p < 0.01 and excess alcohol intake and cannabis use (OR = 6.26, 95%CI = 1.45-27.02, p =  .01 were observed as social risk factors for infection.The continued consistent presence of the Mercian strain suggests ongoing community transmission. Whilst significant associations have been found, there may be other common risk factors yet to be identified. Future investigations should focus on targeting the relevant risk groups and elucidating the biological factors that mediate continued transmission of this strain.

  6. Spatial patterns in accretion on barrier-island salt marshes

    NARCIS (Netherlands)

    Groot, de A.V.; Veeneklaas, R.M.; Kuijper, D.P.J.; Bakker, J.P.

    2011-01-01

    On minerogenic barrier-island salt marshes, sedimentation is spatially heterogeneous. Although the main forcing factors for sedimentation are known, much less is known about the characteristic sizes of this spatial patterning. Such patterning gives information on the spatial component of salt-marsh

  7. Chasing boundaries and cascade effects in a coupled barrier-marsh-lagoon system

    Science.gov (United States)

    Lorenzo-Trueba, Jorge; Mariotti, Giulio

    2017-08-01

    The long-term dynamic evolution of an idealized barrier-marsh-lagoon system experiencing sea-level rise is studied by coupling two existing numerical models. The barrier model accounts for the interaction between shoreface dynamics and overwash flux, which allows the occurrence of barrier drowning. The marsh-lagoon model includes both a backbarrier marsh and an interior marsh, and accounts for the modification of the wave regime associated with changes in lagoon width and depth. Overwash, the key process that connects the barrier shoreface with the marsh-lagoon ecosystems, is formulated to account for the role of the backbarrier marsh. Model results show that a number of factors that are not typically associated with the dynamics of coastal barriers can enhance the rate of overwash-driven landward migration by increasing backbarrier accommodation space. For instance, lagoon deepening could be triggered by marsh edge retreat and consequent export of fine sediment via tidal dispersion, as well as by an expansion of inland marshes and consequent increase in accommodation space to be filled in with sediment. A deeper lagoon results in a larger fraction of sediment overwash being subaqueous, which coupled with a slow shoreface response sending sediment onshore can trigger barrier drowning. We therefore conclude that the supply of fine sediments to the back-barrier and the dynamics of both the interior and backbarrier marsh can be essential for maintaining the barrier system under elevated rates of sea-level rise. Our results highlight the importance of considering barriers and their associated backbarriers as part of an integrated system in which sediment is exchanged.

  8. Coatal salt marshes and mangrove swamps in China

    Science.gov (United States)

    Yang, Shi-Lun; Chen, Ji-Yu

    1995-12-01

    Based on plant specimen data, sediment samples, photos, and sketches from 45 coastal crosssections, and materials from two recent countrywide comprehensive investigations on Chinese coasts and islands, this paper deals with China’s vegetative tidal-flats: salt marshes and mangrove swamps. There are now 141700 acres of salt marshes and 51000 acres of mangrove swamps which together cover about 30% of the mud-coast area of the country and distribute between 18°N (Southern Hainan Island) and 41 °N (Liaodong Bay). Over the past 45 years, about 1750000 acres of salt marshes and 49400 acres of mangrove swamps have been reclaimed. The 2.0×109 tons of fine sediments input by rivers into the Chinese seas form extensive tidal flats, the soil basis of coastal helophytes. Different climates result in the diversity of vegetation. The 3˜8 m tidal range favors intertidal zone development. Of over 20 plant species in the salt marshes, native Suaeda salsa, Phragmites australis, Aeluropus littoralis, Zoysia maerostachys, Imperata cylindrica and introduced Spartina anglica are the most extensive in distribution. Of the 41 mangrove swamps species, Kandelia candel, Bruguiera gymnorrhiza, Excoecaria agallocha and Avicennia marina are much wider in latitudinal distribution than the others. Developing stages of marshes originally relevant to the evolution of tidal flats are given out. The roles of pioneer plants in decreasing flood water energy and increasing accretion rate in the Changjiang River delta are discussed.

  9. Accretion rates in salt marshes in the Eastern Scheldt, South-West Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Oenema, O.; DeLaune, R.D.

    1988-04-01

    Vertical accretion and sediment accumulation rates were determined from the distribution of /sup 137/Cs in sediment cores, from historic documents, and from artificial white-coloured tracer layers in salt marshes in the Eastern Scheldt. Salt marsh accretion is related to the steady rise of the mean high tide in the Eastern Scheldt during the last few decades. Mean accretion rates vary from 0.4-0.9 cm year/sup -1/ in the St Annaland marsh to 1.0-1.5 cm year/sup -1/ in the Rattekaai marsh. Sediment accumulation in accreting marshes exceed the loss of sediment, by retreat of the marsh cliffs, by a factor of 10-20. Short-term spatial and temporal variations in accretion rates are large. Spatial variations are associated with levee and backmarsh sites and the density of marsh vegetation. Temporal variations are mainly related to fluctuations in hydrodynamic conditions. The net vertical accretion rate of organic carbon is 0.4 +- 0.1 kg m/sup -2/ year/sup -1/, approximately half this rate is associated with the current deposit, and the other half with net additions from the belowground root biomass. A simple model for the root biomass distribution of Spartina anglica with depth and the depth-dependent fossilization of root biomass in sediments of the Rattekaai marsh is presented.

  10. Analysis of change in marsh types of coastal Louisiana, 1978-2001

    Science.gov (United States)

    Linscombe, Robert G.; Hartley, Stephen B.

    2011-01-01

    Scientists and geographers have provided multiple datasets and maps to document temporal changes in vegetation types and land-water relationships in coastal Louisiana. Although these maps provide useful historical information, technological limitations prevented these and other mapping efforts from providing sufficiently detailed calculations of areal changes and shifts in habitat coverage. The current analysis of habitat change draws upon these past mapping efforts but is based on an advanced, geographic information system dataset that was created by using Landsat 5 Thematic Mapper imagery and digital orthophoto quarter quadrangles. The objective of building this dataset was to more specifically define land-water relationships over time in coastal Louisiana, and it provides the most detailed analysis of vegetation shifts to date. In the current study, we have attempted to explain these vegetation shifts by interpreting them in the context of rainfall records, data from the Palmer Drought Severity Index, and salinity data. During the 23 years we analyzed, total marsh acreage decreased, with conversion of marsh to open water. Furthermore, the general trend across coastal Louisiana was a shift to increasingly fresh marsh types. Although fresh marsh remained almost the same during the 1978-88 study period, there were greater increases during the 1988-2001 study periods. Intermediate marsh followed the same pattern, whereas brackish marsh showed a reverse (decreasing) pattern. Changes in saline (saltwater) marsh were minimal. Interpreting shifts in marsh vegetation types by using climate and salinity data provides better understanding of factors influencing these changes and, therefore, can improve our ability to make predictions about future marsh loss related to vegetation changes. Results of our study indicate that precipitation fluctuations prior to vegetation surveys impacted salinities differently across the coast. For example, a wet 6 months prior to the survey

  11. High spatial variability in biogeochemical rates and microbial communities across Louisiana salt marsh landscapes

    Science.gov (United States)

    Roberts, B. J.; Chelsky, A.; Bernhard, A. E.; Giblin, A. E.

    2017-12-01

    Salt marshes are important sites for retention and transformation of carbon and nutrients. Much of our current marsh biogeochemistry knowledge is based on sampling at times and in locations that are convenient, most often vegetated marsh platforms during low tide. Wetland loss rates are high in many coastal regions including Louisiana which has the highest loss rates in the US. This loss not only reduces total marsh area but also changes the relative allocation of subhabitats in the remaining marsh. Climate and other anthropogenic changes lead to further changes including inundation patterns, redox conditions, salinity regimes, and shifts in vegetation patterns across marsh landscapes. We present results from a series of studies examining biogeochemical rates, microbial communities, and soil properties along multiple edge to interior transects within Spartina alterniflora across the Louisiana coast; between expanding patches of Avicennia germinans and adjacent S. alterniflora marshes; in soils associated with the four most common Louisiana salt marsh plants species; and across six different marsh subhabitats. Spartina alterniflora marsh biogeochemistry and microbial populations display high spatial variability related to variability in soil properties which appear to be, at least in part, regulated by differences in elevation, hydrology, and redox conditions. Differences in rates between soils associated with different vegetation types were also related to soil properties with S. alterniflora soils often yielding the lowest rates. Biogeochemical process rates vary significantly across marsh subhabitats with individual process rates differing in their hotspot habitat(s) across the marsh. Distinct spatial patterns may influence the roles that marshes play in retaining and transforming nutrients in coastal regions and highlight the importance of incorporating spatial sampling when scaling up plot level measurements to landscape or regional scales.

  12. Assessment of undiscovered oil and gas resources in the Spraberry Formation of the Midland Basin, Permian Basin Province, Texas, 2017

    Science.gov (United States)

    Marra, Kristen R.; Gaswirth, Stephanie B.; Schenk, Christopher J.; Leathers-Miller, Heidi M.; Klett, Timothy R.; Mercier, Tracey J.; Le, Phuong A.; Tennyson, Marilyn E.; Finn, Thomas M.; Hawkins, Sarah J.; Brownfield, Michael E.

    2017-05-15

    Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean resources of 4.2 billion barrels of oil and 3.1 trillion cubic feet of gas in the Spraberry Formation of the Midland Basin, Permian Basin Province, Texas.

  13. Comparison of trace metals in South Carolina floodplain and marsh sediments

    International Nuclear Information System (INIS)

    Gardner, L.R.; Chen, H.S.; Settlemyre, J.L.

    1978-01-01

    A comparative study of trace metals (copper, zinc, lead, and molybdenum) in sediment cores from a pristine marsh near North Inlet, S.C., a polluted marsh near Charleston Harbor, S.C., and South Carolina river floodplains indicates that the Charleston Harbor marsh samples have significantly higher concentrations of copper, zinc, and lead than either North Inlet samples or river floodplain samples. It is not clear, however, whether this result can be attributed to industrial contamination because the peak concentrations of copper and zinc in cores from the Charleston Harbor marsh occur at depths between 10 and 60 cm rather than at or near the sediment surface, as is the case for well-documented occurrences of contaminated marine sediments. Also, both marsh areas show similar linear relationships for copper vs. zinc, which suggest that both areas received the same relative inputs of copper and zinc from similar or identical sources and that the differences in concentrations between the two areas are due to differences in the rates of accumulation. Natural mechanisms are suggested to explain the higher content of copper and zinc in Charleston Harbor vs. North Inlet marsh sediments and the variable depth of peak copper and zinc concentrations

  14. Mosquitoes Associated with Ditch-Plugged and Control Tidal Salt Marshes on the Delmarva Peninsula

    Directory of Open Access Journals (Sweden)

    Paul T. Leisnham

    2011-07-01

    Full Text Available A study was conducted during the summer of 2009 (from July to September to characterize mosquito communities among different habitats in five historically ditched tidal salt marshes and three adjacent wooded areas in the E.A. Vaughn Wetland Management Area on the Maryland Delmarva Peninsula, USA. Study marshes are characteristic of Atlantic coastal salt marshes that had undergone grid ditching from the 1930s to 1950s. In the autumn of 2008 (October and November ditches were plugged near their outlets in two (‘experimental’ marshes with the aim to restore their natural tidal hydrology. The three other marshes were not plugged. Marshes were sampled from July to September in 2009 by using standard dip count method. A total of 2,457 mosquito larvae representing six species were collected on 15.4% (86/557 of all sample occasions and 399 adults representing four mosquito species were collected from landing counts. Aedes sollicitans, Anopheles bradleyi and Culex salinarius were the most common species collected in larval habitats, and Ae. sollicitans was the most common adult collected. Wooded habitats had more total mosquitoes, were also more frequently occupied by mosquitoes and had higher densities of mosquitoes than marsh habitats. Almost all larvae collected from marshes were from one experimental and one control site. The majority of larvae at the control site were Ae. sollicitans in marsh pannes while Cx. salinarius, An. bradleyi, Ae. cantator, and Ae. sollicitans were collected in high numbers from ditches at the experimental site. We found a difference in the proportion of marsh pannes occupied by Ae. sollicitans but not total mosquitoes sampled 4–5 days after spring tide events than on other occasions. Salinity measures of 42 larval habitats showed lower median salinity in mosquito-occupied habitats (11.5 ppt than unoccupied habitats (20.1 ppt, and in habitats in wooded areas followed by ditches and pannes in marsh areas. The results of

  15. Impacts of Intensified Agriculture Developments on Marsh Wetlands

    Directory of Open Access Journals (Sweden)

    Zhaoqing Luan

    2013-01-01

    Full Text Available A spatiotemporal analysis on the changes in the marsh landscape in the Honghe National Nature Reserve, a Ramsar reserve, and the surrounding farms in the core area of the Sanjiang Plain during the past 30 years was conducted by integrating field survey work with remote sensing techniques. The results indicated that intensified agricultural development had transformed a unique natural marsh landscape into an agricultural landscape during the past 30 years. Ninety percent of the natural marsh wetlands have been lost, and the areas of the other natural landscapes have decreased very rapidly. Most dry farmland had been replaced by paddy fields during the progressive change of the natural landscape to a farm landscape. Attempts of current Chinese institutions in preserving natural wetlands have achieved limited success. Few marsh wetlands have remained healthy, even after the establishment of the nature reserve. Their ecological qualities have been declining in response to the increasing threats to the remaining wetland habitats. Irrigation projects play a key role in such threats. Therefore, the sustainability of the natural wetland ecosystems is being threatened by increased regional agricultural development which reduced the number of wetland ecotypes and damaged the ecological quality.

  16. Searching for the Source of Salt Marsh Buried Mercury.

    Science.gov (United States)

    Brooke, C. G.; Nelson, D. C.; Fleming, E. J.

    2016-12-01

    Salt marshes provide a barrier between upstream mercury contamination and coastal ecosystems. Mercury is sorbed, transported, and deposited in estuarine systems. Once the upstream mercury source has been remediated, the downstream mercury contaminated salt marsh sediments should become "capped" or buried by uncontaminated sediments preventing further ecosystem contamination. Downstream from a remediated mercury mine, an estuarine intertidal marsh in Tomales Bay, CA, USA, scavengers/predators (e.g. Pachygrapsus crassipes, Lined Shore Crab) have leg mercury concentrations as high as 5.5 ppm (dry wt./dry wt.), which increase significantly with crab size, a surrogate for trophic level. These elevated mercury concentrations suggests that "buried" mercury is rereleased into the environment. To locate possible sources of mercury release in Walker Marsh, we sampled a transect across the marsh that included diverse micro-environments (e.g. rhizoshere, stratified sediments, faunal burrows). From each location we determined the sediment structure, sediment color, total sediment mercury, total sediment iron, and microbial composition (n = 28). Where flora or fauna had perturbed the sediment, mercury concentrations were 10% less than undisturbed stratified sediments (1025 ppb vs. 1164 ppb, respectively). High-throughput SSU rRNA gene sequencing and subsequent co-occurrence network analysis genera indicated that in flora- or fauna- perturbed sediments there was an increased likelihood that microbial genera contained mercury mobilizing genes (94% vs 57%; in perturbed vs stratified sediments, respectively). Our observations are consistent with findings by others that in perturbed sites mercury mobility increased. We did however identify a microbial and geochemical profile with increased mercury mobility. For future work we plan to quantify the role these micro-environments have on mercury-efflux from salt marshes.

  17. Elevation dynamics in a restored versus a submerging salt marsh in Long Island Sound

    Science.gov (United States)

    Anisfeld, Shimon C.; Hill, Troy D.; Cahoon, Donald R.

    2016-01-01

    Accelerated sea-level rise (SLR) poses the threat of salt marsh submergence, especially in marshes that are relatively low-lying. At the same time, restoration efforts are producing new low-lying marshes, many of which are thriving and avoiding submergence. To understand the causes of these different fates, we studied two Long Island Sound marshes: one that is experiencing submergence and mudflat expansion, and one that is undergoing successful restoration. We examined sedimentation using a variety of methods, each of which captures different time periods and different aspects of marsh elevation change: surface-elevation tables, marker horizons, sediment cores, and sediment traps. We also studied marsh hydrology, productivity, respiration, nutrient content, and suspended sediment. We found that, despite the expansion of mudflat in the submerging marsh, the areas that remain vegetated have been gaining elevation at roughly the rate of SLR over the last 10 years. However, this elevation gain was only possible thanks to an increase in belowground volume, which may be a temporary response to waterlogging. In addition, accretion rates in the first half of the twentieth century were much lower than current rates, so century-scale accretion in the submerging marsh was lower than SLR. In contrast, at the restored marsh, accretion rates are now averaging about 10 mm yr−1 (several times the rate of SLR), much higher than before restoration. The main cause of the different trajectories at the two marshes appeared to be the availability of suspended sediment, which was much higher in the restored marsh. We considered and rejected alternative hypotheses, including differences in tidal flooding, plant productivity, and nutrient loading. In the submerging marsh, suspended and deposited sediment had relatively high organic content, which may be a useful indicator of sediment starvation.

  18. Trematodes in snails near raccoon latrines suggest a final host role for this mammal in California Salt Marshes

    Science.gov (United States)

    Lafferty, K.D.; Dunham, E.J.

    2005-01-01

    Of the 18 trematode species that use the horn snail, Cerithidea californica, as a first intermediate host, 6 have the potential to use raccoons as a final host. The presence of raccoon latrines in Carpinteria Salt Marsh, California, allowed us to investigate associations between raccoons and trematodes in snails. Two trematode species, Probolocoryphe uca and Stictodora hancocki, occurred at higher prevalences in snails near raccoon latrines than in snails away from latrines, suggesting that raccoons may serve as final hosts for these species. Fecal remains indicated that raccoons fed on shore crabs, the second intermediate host for P. uca, and fish, the second intermediate host for S. hancocki. The increase in raccoon populations in the suburban areas surrounding west coast salt marshes could increase their importance as final hosts for trematodes in this system. ?? American Society of Parasitologists 2005.

  19. Numerical modeling of salt marsh morphological change induced by Hurricane Sandy

    Science.gov (United States)

    Hu, Kelin; Chen, Qin; Wang, Hongqing; Hartig, Ellen K.; Orton, Philip M.

    2018-01-01

    The salt marshes of Jamaica Bay serve as a recreational outlet for New York City residents, mitigate wave impacts during coastal storms, and provide habitat for critical wildlife species. Hurricanes have been recognized as one of the critical drivers of coastal wetland morphology due to their effects on hydrodynamics and sediment transport, deposition, and erosion processes. In this study, the Delft3D modeling suite was utilized to examine the effects of Hurricane Sandy (2012) on salt marsh morphology in Jamaica Bay. Observed marsh elevation change and accretion from rod Surface Elevation Tables and feldspar Marker Horizons (SET-MH) and hydrodynamic measurements during Hurricane Sandy were used to calibrate and validate the wind-waves-surge-sediment transport-morphology coupled model. The model results agreed well with in situ field measurements. The validated model was then used to detect salt marsh morphological change due to Sandy across Jamaica Bay. Model results indicate that the island-wide morphological changes in the bay's salt marshes due to Sandy were in the range of −30 mm (erosion) to +15 mm (deposition), and spatially complex and heterogeneous. The storm generated paired deposition and erosion patches at local scales. Salt marshes inside the west section of the bay showed erosion overall while marshes inside the east section showed deposition from Sandy. The net sediment amount that Sandy brought into the bay is only about 1% of the total amount of reworked sediment within the bay during the storm. Numerical experiments show that waves and vegetation played a critical role in sediment transport and associated wetland morphological change in Jamaica Bay. Furthermore, without the protection of vegetation, the marsh islands of Jamaica Bay would experience both more erosion and less accretion in coastal storms.

  20. Elders Point East Marsh Island Restoration Monitoring Data Analysis

    Science.gov (United States)

    2017-09-21

    accounting for more than 90% of the measured biomass on average, indicative of a well-established marsh (Figure 12). For Elders East the data indicated...61 3.3 Other Biological and Physical Measures ...Figure 9. Growth measurements at Elders East and JoCo Marsh. ....................................................... 20 Figure 10. Stem survival at

  1. High Spatial resolution remote sensing for salt marsh change detection on Fire Island National Seashore

    Science.gov (United States)

    Campbell, A.; Wang, Y.

    2017-12-01

    Salt marshes are under increasing pressure due to anthropogenic stressors including sea level rise, nutrient enrichment, herbivory and disturbances. Salt marsh losses risk the important ecosystem services they provide including biodiversity, water filtration, wave attenuation, and carbon sequestration. This study determines salt marsh change on Fire Island National Seashore, a barrier island along the south shore of Long Island, New York. Object-based image analysis was used to classifying Worldview-2, high resolution satellite, and topobathymetric LiDAR. The site was impacted by Hurricane Sandy in October of 2012 causing a breach in the Barrier Island and extensive overwash. In situ training data from vegetation plots were used to train the Random Forest classifier. The object-based Worldview-2 classification achieved an overall classification accuracy of 92.75. Salt marsh change for the study site was determined by comparing the 2015 classification with a 1997 classification. The study found a shift from high marsh to low marsh and a reduction in Phragmites on Fire Island. Vegetation losses were observed along the edge of the marsh and in the marsh interior. The analysis agreed with many of the trends found throughout the region including the reduction of high marsh and decline of salt marsh. The reduction in Phragmites could be due to the species shrinking niche between rising seas and dune vegetation on barrier islands. The complex management issues facing salt marsh across the United States including sea level rise and eutrophication necessitate very high resolution classification and change detection of salt marsh to inform management decisions such as restoration, salt marsh migration, and nutrient inputs.

  2. Wave attenuation across a tidal marsh in San Francisco Bay

    Science.gov (United States)

    Foster-Martinez, Madeline R.; Lacy, Jessica; Ferner, Matthew C.; Variano, Evan A.

    2018-01-01

    Wave attenuation is a central process in the mechanics of a healthy salt marsh. Understanding how wave attenuation varies with vegetation and hydrodynamic conditions informs models of other marsh processes that are a function of wave energy (e.g. sediment transport) and allows for the incorporation of marshes into coastal protection plans. Here, we examine the evolution of wave height across a tidal salt marsh in San Francisco Bay. Instruments were deployed along a cross-shore transect, starting on the mudflat and crossing through zones dominated by Spartina foliosa and Salicornia pacifica. This dataset is the first to quantify wave attenuation for these vegetation species, which are abundant in the intertidal zone of California estuaries. Measurements were collected in the summer and winter to assess seasonal variation in wave attenuation. Calculated drag coefficients of S. foliosa and S. pacifica were similar, indicating equal amounts of vegetation would lead to similar energy dissipation; however, S. pacifica has much greater biomass close to the bed (<20 cm) and retains biomass throughout the year, and therefore, it causes more total attenuation. S. foliosa dies back in the winter, and waves often grow across this section of the marsh. For both vegetation types, attenuation was greatest for low water depths, when the vegetation was emergent. For both seasons, attenuation rates across S. pacifica were the highest and were greater than published attenuation rates across similar (Spartina alterniflora) salt marshes for the comparable depths. These results can inform designs for marsh restorations and management plans in San Francisco Bay and other estuaries containing these species.

  3. Marsh Soil Responses to Nutrients: Belowground Structural and Organic Properties.

    Science.gov (United States)

    Coastal marsh responses to nutrient enrichment apparently depend upon soil matrix and whether the system is primarily biogenic or minerogenic. Deteriorating organic rich marshes (Jamaica Bay, NY) receiving wastewater effluent had lower belowground biomass, organic matter, and soi...

  4. Environmental assessment of Al-Hammar Marsh, Southern Iraq

    Directory of Open Access Journals (Sweden)

    Hind Fadhil Abdullah Al-Gburi

    2017-02-01

    Discussion and conclusions: Decreasing of Tigris and Euphrates discharges during the past decades due to drought conditions and upstream damming, as well as the increasing stress of wastewater effluents from anthropogenic activities, led to degradation of the downstream Al-Hammar Marsh water quality in terms of physical, chemical, and biological properties. As such properties were found to consistently exceed the historical and global quality objectives. However, element concentration decreasing trend at the marsh outlet station compared to other stations indicate that the marsh plays an important role as a natural filtration and bioremediation system. Higher element concentrations in winter were due to runoff from the washing of the surrounding Sabkha during flooding by winter rainstorms. Finally, the high concentrations of heavy metals in fish samples can be attributed to bioaccumulation and biomagnification processes.

  5. Gross nitrous oxide production drives net nitrous oxide fluxes across a salt marsh landscape.

    Science.gov (United States)

    Yang, Wendy H; Silver, Whendee L

    2016-06-01

    Sea level rise will change inundation regimes in salt marshes, altering redox dynamics that control nitrification - a potential source of the potent greenhouse gas, nitrous oxide (N2 O) - and denitrification, a major nitrogen (N) loss pathway in coastal ecosystems and both a source and sink of N2 O. Measurements of net N2 O fluxes alone yield little insight into the different effects of redox conditions on N2 O production and consumption. We used in situ measurements of gross N2 O fluxes across a salt marsh elevation gradient to determine how soil N2 O emissions in coastal ecosystems may respond to future sea level rise. Soil redox declined as marsh elevation decreased, with lower soil nitrate and higher ferrous iron in the low marsh compared to the mid and high marshes (P production was highest in the low marsh and lowest in the mid-marsh (P = 0.02), whereas gross N2 O consumption did not differ among marsh zones. Thus, variability in gross N2 O production rates drove the differences in net N2 O flux among marsh zones. Our results suggest that future studies should focus on elucidating controls on the processes producing, rather than consuming, N2 O in salt marshes to improve our predictions of changes in net N2 O fluxes caused by future sea level rise. © 2015 John Wiley & Sons Ltd.

  6. Ammonium transformation in a nitrogen-rich tidal freshwater marsh

    DEFF Research Database (Denmark)

    Gribsholt, B.; Andersson, M.; Boschker, H.T.S.

    2006-01-01

    The fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient rich Scheldt River, Belgium, was quantified in a whole ecosystem 15N labeling experiment. In late summer (September) we added 15N-NH4+ to the flood water entering a 3477 m2 tidal freshwater marsh...

  7. Louisiana Marsh Management Plan 1995

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — We sampled experimental research areas in the Barataria Basin of Louisiana during March and May, 1995, to examine the effects of structural marsh management on...

  8. Plathelminth abundance in North Sea salt marshes: environmental instability causes high diversity

    Science.gov (United States)

    Armonies, Werner

    1986-09-01

    Although supralittoral salt marshes are habitats of high environmental instability, the meiofauna is rich in species and abundance is high. The community structure of free-living Plathelminthes (Turbellaria) in these salt marshes is described. On an average, 104 individuals are found below an area of 10 cm2. The average species density in ungrazed salt marshes is 11.3 below 10 cm2 and 45.2 below 100 cm2, indicating strong small-scale heterogenity. The faunal similarity between sediment and the corresponding above-ground vegetation is higher than between adjacent sample sites. Species prefer distinct ranges of salinity. In the lower part of the supralittoral salt marshes, the annual fluctuations of salinity are strongest and highly unpredictable. This region is richest in plathelminth species and abundance; diversity is highest, and the faunal composition of parallel samples is quite similar. In the upper part of the supralittoral salt marshes, the annual variability of salinity is lower, plathelminths are poor in species diversity and abundance. Parallel samples often have no species in common. Thus, those salt marsh regions with the most unstable environment are inhabited by the most diverse species assemblage. Compared to other littoral zones of the North Sea, however, plathelminth diversity in salt marshes is low. The observed plathelminth diversity pattern can apparently be explained by the “dynamic equilibrium model” (Huston, 1979).

  9. Stratigraphic response of salt marshes to slow rates of sea-level change

    Science.gov (United States)

    Daly, J.; Bell, T.

    2006-12-01

    Conventional models of salt-marsh development show an idealized spatial relationship between salt-marsh floral and foraminiferal zones, where the landward margin of the marsh gradually migrates inland in response to sea-level rise. This model predicts that transgression will result in persistent and possibly expanded salt marshes at the surface, depending on a variety of factors including sediment supply, hydrologic conditions, tidal range, and rate of sea-level rise. However, in areas with abundant sediment supply and slow rates of sea- level rise, the extent of back-barrier salt marshes may decline over time as the barrier-spits mature. Sea level around the northeast coast of Newfoundland is rising at a very slow rate during the late Holocene (flora. These transitions are interpreted to reflect the progradation of the spit, decreased tidal exchange in the back-barrier, and increased influence of freshwater streams discharging into the back-barrier setting. Decreased marine influence on the back-barrier environment leads to a floral and faunal shift associated with a regressive stratigraphy in an area experiencing sea-level rise. For studies of Holocene sea-level change requiring salt-marsh stratigraphic records, it is necessary to account for changing micro-environments to locate sites appropriate for study; salt marshes may play an important role in defining the record, but may not exist at the surface to guide investigation.

  10. Regulation of salt marsh mosquito populations by the 18.6-yr lunar-nodal cycle.

    Science.gov (United States)

    Rochlin, Ilia; Morris, James T

    2017-08-01

    The 18.6-yr lunar-nodal cycle drives changes in tidal amplitude globally, affecting coastal habitat formation, species and communities inhabiting rocky shores, and salt marsh vegetation. However, the cycle's influence on salt marsh fauna lacked sufficient long-term data for testing its effect. We circumvented this problem by using salt marsh mosquito records obtained over a period of over four decades in two estuaries in the northeastern USA. Salt marsh mosquito habitat is near the highest tide level where the impact of the nodal cycle on flood frequency is greatest. Wavelet spectral and cross-correlation analyses revealed periodicity in salt marsh mosquito abundance that was negatively correlated with tidal amplitude. Tidal amplitude was a significant predictor of salt marsh mosquito abundance with the cycle maxima coinciding with lower mosquito populations, possibly due to access by predatory fish. However, these effects were detected only at the location with extensive salt marsh habitat and astronomical tides and were weakened or lacked significance at the location with small microtidal salt marshes and wind-driven tides. Mosquitoes can serve as proxy indicators for numerous invertebrate species on the salt marsh. These predictable cycles and their effects need to be taken into consideration when investigating, restoring, or managing intertidal communities that are also facing sea-level rise. © 2017 by the Ecological Society of America.

  11. Participation motivation in martial artists in the west midlands region of England.

    Science.gov (United States)

    Jones, Gareth W; Mackay, Ken S; Peters, Derek M

    2006-01-01

    The objectives were to identify the participation motivations and the perceived importance of certain participation factors in martial artists in the West Midlands, England, UK. A 28-item adapted version of the Participation Motivation Questionnaire with additional demographic questions was distributed to 30 martial arts clubs in the West Midlands region. Eight questions that assessed the perceived importance for participation of progression through grades, learning self defence skills, technical ability of instructors, cost of participating, development of confidence, underpinning philosophy and instructional style were included. Seventy-five questionnaires were returned from a total of 11 clubs from across representing practitioners in Tai Chi, Karate, Kung fu, Aikido, Jeet Kune Do, British Free Fighting, Taekwon-Do and Jujitsu. Results indicated that the rank order in terms of participation motives was: 1-Affiliation; 2-Friendship; 3-Fitness; 4-Reward/status; 5-Competition; 6-Situational and 7-Skill development. Participants who trained for more than 4 hours per week placed greater importance on the underpinning philosophy of the martial art. Findings suggest that whilst there is a gender discrepancy in participation level, once engaged, females were equally committed to weekly training. The 'style' of the instructor is of paramount importance for enhancing student motivation to participate. High volume practitioners would appear to be fully immersed in the holistic appreciation of the martial art through increased value placed on its underpinning philosophy. Key PointsWhilst there is a gender discrepancy in participation level, once engaged, females were equally committed to weekly training.The four most important participation motivations evident were 'Affiliation', 'Fitness', 'Skill Development' and 'Friendship'.The three least influential motives were 'Rewards/status; 'Situational' and 'Competition'. " There were no significant gender or experience

  12. Greenhouse gas emissions from a created brackish marsh in eastern North Carolina

    Science.gov (United States)

    Shiau, Yo-Jin; Burchell, Michael R.; Krauss, Ken W.; Birgand, François; Broome, Stephen W.

    2016-01-01

    Tidal marsh creation helps remediate global warming because tidal wetlands are especially proficient at sequestering carbon (C) in soils. However, greenhouse gas (GHG) losses can offset the climatic benefits gained from C storage depending on how these tidal marshes are constructed and managed. This study attempts to determine the GHG emissions from a 4–6 year old created brackish marsh, what environmental factors governed these emissions, and how the magnitude of the fluxes relates to other wetland ecosystems. The static flux chamber method was used to measure GHG fluxes across three distinct plant zones segregated by elevation. The major of soil GHG fluxes from the marsh were from CO2 (−48–192 mg C m-2 h-1), although it was near the lower end of values reported from other wetland types having lower salinities, and would mostly be offset by photosynthetic uptake in this created brackish marsh. Methane flux was also low (−0.33–0.86 mg C m-2 h-1), likely inhibited by the high soil SO42−and soil redox potentials poised above −150 mV in this in this created brackish marsh environment. Low N2O flux (−0.11–0.10 mg N m-2 h-1) was due to low soil NO3− and soil redox conditions favoring complete denitrification. GHG fluxes from this created brackish marsh were generally lower than those recorded from natural marshes, suggesting that C sequestration may not be offset by the radiative forcing from soil GHG emissions if projects are designed properly.

  13. Coastal marsh degradation: modeling the influence of vegetation die-off patterns on flow and sedimentation

    Science.gov (United States)

    Schepers, Lennert; Wang, Chen; Kirwan, Matthew; Belluco, Enrica; D'Alpaos, Andrea; Temmerman, Stijn

    2014-05-01

    Coastal marshes are vulnerable ecosystems that provide ecosystem functions such as storm protection and carbon sequestration. However, degradation of vegetated marshes into bare tidal flats or open water has been reported as a worldwide phenomenon, threatening their valuable wetland functions. Moreover, tidal marshes and bare flats are considered as alternative stable ecosystem states, which implies that, once vegetated marshes have degraded to bare flats, the (re)conversion from bare flats to marsh vegetation may be very difficult. Recent aerial photo analysis has demonstrated that the degradation or die-off of a marsh area is a spatial process, whereby vegetation is typically replaced by non-vegetated areas in the form of interior marsh pools, also known as ponds or marsh basins. On a small scale, these pools have similar characteristics among different marshes worldwide: pools that are located further away from tidal channels and with broad channel connections to the tidal channel system appear to have low surface elevations and a low probability for marsh recovery (this is re-establishment of vegetation on the surface). Interior pools located closer to, but that are not connected to channels on the other hand, are positioned on higher elevations and are more likely to recover. These findings may have important implications for the restoration potential of degraded marshes and their functions. We hypothesize that bio-geomorphologic interactions are the main mechanisms causing these differences in elevation and recovery potential of interior marsh pools: pools that are not connected to the channel system, are separated from the channel by vegetation, which reduces the flow velocity, increases sedimentation and may explain our observation of higher surface elevation of this type of pools. In contrast, pools that are connected with the channel system are not protected by vegetation and will experience higher flow velocities and lower sedimentation rates or even

  14. Tritium kinetics in a freshwater marsh ecosystem

    International Nuclear Information System (INIS)

    Adams, L.W.

    1976-01-01

    Ten curies of tritium (as tritiated water, HTO) were applied to a 2-ha enclosed Lake Erie marsh in northwestern Ohio on 29 October 1973. Tritium kinetics in the marsh water, bottom sediment, and selected aquatic plants and animals were determined. Following HTO application, peak tritium levels in the sediment were observed on day 13 in the top 1-cm layer, on day 27 at the 5-cm depth, and on day 64 at the 10-cm depth. Peak levels at 15 and 20 cm were not discernible, although there was some movement of HTO to the 20-cm depth. A model based on diffusion theory described tritium movement through the sediment. Unbound and bound tritium levels in curly-leaf pondweed (Potamogeton crispus), pickerelweed (Pontederia cordata), and smartweed (Polygonum lapathifolium) generally tended to follow tritium levels in marsh water. The unbound tritium:marsh water tritium ratio was significantly larger (P < 0.001) in curly-leaf pondweed than in either of the two emergents. Tritium uptake into the unbound compartments of crayfish (Procambarus blandingi), carp (Cyprinus carpio), and bluegills (Lepomis macrochirus) was rapid. For crayfish, maximum HTO levels were observed on days 3 and 2 for viscera and muscle, respectively. Unbound HTO in carp viscera peaked on day 2, and levels in carp muscle reached a maximum in 4 hours. Maximum levels of unbound HTO in bluegill viscera and muscle were observed on day 1. After peak levels were obtained, unbound HTO paralleled marsh water HTO activity in all species. Tritium uptake into the bound compartments was not as rapid nor were the levels as high as for unbound HTO in any of the species. Peak bound levels in crayfish viscera were observed on day 20 and maximum levels in muscle were noted on day 10. Bound tritium in carp viscera and muscle reached maximum levels on day 20. In bluegills, peaks were reached on days 7 and 5 for viscera and muscle, respectively. Bound tritium in all species decreased following maximum levels

  15. Why does it take so long? ‘Lean processing’ in the aseptic compounding unit at the Midland Regional Hospital Tullamore

    LENUS (Irish Health Repository)

    Greene, C

    2011-06-01

    Increasing numbers of oncology\\/haematology patients attending Midland Regional Hospital Tullamore (MRHT) has increased the workload of the Regional Oncology Haematology Pharmacy (ROHP) compounding unit. Staff restrictions require optimisation of current workflow practices. This audit (November 2010 and June 2011) focused on workflow in the aseptic compounding unit.\\r\

  16. Effects of invasive cordgrass on presence of Marsh Grassbird in an area where it is not native.

    Science.gov (United States)

    Ma, Zhijun; Gan, Xiaojing; Choi, Chi-Yeung; Li, Bo

    2014-02-01

    The threatened Marsh Grassbird (Locustella pryeri) first appeared in the salt marsh in east China after the salt marsh was invaded by cordgrass (Spartina alterniflora), a non-native invasive species. To understand the dependence of non-native Marsh Grassbird on the non-native cordgrass, we quantified habitat use, food source, and reproductive success of the Marsh Grassbird at the Chongming Dongtan (CMDT) salt marsh. In the breeding season, we used point counts and radio-tracking to determine habitat use by Marsh Grassbirds. We analyzed basal food sources of the Marsh Grassbirds by comparing the δ(13) C isotope signatures of feather and fecal samples of birds with those of local plants. We monitored the nests through the breeding season and determined the breeding success of the Marsh Grassbirds at CMDT. Density of Marsh Grassbirds was higher where cordgrass occurred than in areas of native reed (Phragmites australis) monoculture. The breeding territory of the Marsh Grassbird was composed mainly of cordgrass stands, and nests were built exclusively against cordgrass stems. Cordgrass was the major primary producer at the base of the Marsh Grassbird food chain. Breeding success of the Marsh Grassbird at CMDT was similar to breeding success within its native range. Our results suggest non-native cordgrass provides essential habitat and food for breeding Marsh Grassbirds at CMDT and that the increase in Marsh Grassbird abundance may reflect the rapid spread of cordgrass in the coastal regions of east China. Our study provides an example of how a primary invader (i.e., cordgrass) can alter an ecosystem and thus facilitate colonization by a second non-native species. © 2013 Society for Conservation Biology.

  17. Greenhouse gas emissions in salt marshes and their response to nitrogen loading

    Science.gov (United States)

    Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Carey, J.

    2015-12-01

    Salt marshes play an important role in global and regional carbon and nitrogen cycling. Anthropogenic nitrogen loading may alter greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient (between 1 and 10 gN m-2y-1) were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. We found that the studied salt marsh was a significant carbon sink (NEP ~ 380 gC m-2y-1). CH4 fluxes are 3 orders of magnitude less than CO2 fluxes in the salt marsh. Carbon fluxes are driven by light, salinity, tide, and temperature. We conclude that restoration or conservation of this carbon sink has a significant social benefit for carbon credit.

  18. Zooming in and out: Scale dependence of extrinsic and intrinsic factors affecting salt marsh erosion

    Science.gov (United States)

    Wang, Heng; van der Wal, Daphne; Li, Xiangyu; van Belzen, Jim; Herman, Peter M. J.; Hu, Zhan; Ge, Zhenming; Zhang, Liquan; Bouma, Tjeerd J.

    2017-07-01

    Salt marshes are valuable ecosystems that provide important ecosystem services. Given the global scale of marsh loss due to climate change and coastal squeeze, there is a pressing need to identify the critical extrinsic (wind exposure and foreshore morphology) and intrinsic factors (soil and vegetation properties) affecting the erosion of salt marsh edges. In this study, we quantified rates of cliff lateral retreat (i.e., the eroding edge of a salt marsh plateau) using a time series of aerial photographs taken over four salt marsh sites in the Westerschelde estuary, the Netherlands. In addition, we experimentally quantified the erodibility of sediment cores collected from the marsh edge of these four marshes using wave tanks. Our results revealed the following: (i) at the large scale, wind exposure and the presence of pioneer vegetation in front of the cliff were the key factors governing cliff retreat rates; (ii) at the intermediate scale, foreshore morphology was partially related to cliff retreat; (iii) at the local scale, the erodibility of the sediment itself at the marsh edge played a large role in determining the cliff retreat rate; and (iv) at the mesocosm scale, cliff erodibility was determined by soil properties and belowground root biomass. Thus, both extrinsic and intrinsic factors determined the fate of the salt marsh but at different scales. Our study highlights the importance of understanding the scale dependence of the factors driving the evolution of salt marsh landscapes.

  19. Physical and Biological Regulation of Carbon Sequestration in Tidal Marshes

    Science.gov (United States)

    Morris, J. T.; Callaway, J.

    2017-12-01

    The rate of carbon sequestration in tidal marshes is regulated by complex feedbacks among biological and physical factors including the rate of sea-level rise (SLR), biomass production, tidal amplitude, and the concentration of suspended sediment. We used the Marsh Equilibrium Model (MEM) to explore the effects on C-sequestration across a wide range of permutations of these variables. C-sequestration increased with the rate of SLR to a maximum, then down to a vanishing point at higher SLR when marshes convert to mudflats. An acceleration in SLR will increase C-sequestration in marshes that can keep pace, but at high rates of SLR this is only possible with high biomass and suspended sediment concentrations. We found that there were no feasible solutions at SLR >13 mm/yr for permutations of variables that characterize the great majority of tidal marshes, i.e., the equilibrium elevation exists below the lower vertical limit for survival of marsh vegetation. The rate of SLR resulting in maximum C-sequestration varies with biomass production. C-sequestration rates at SLR=1 mm/yr averaged only 36 g C m-2 yr-1, but at the highest maximum biomass tested (5000 g/m2) the mean C-sequestration reached 399 g C m-2 yr-1 at SLR = 14 mm/yr. The empirical estimate of C-sequestration in a core dated 50-years overestimates the theoretical long-term rate by 34% for realistic values of decomposition rate and belowground production. The overestimate of the empirical method arises from the live and decaying biomass contained within the carbon inventory above the marker horizon, and overestimates were even greater for shorter surface cores.

  20. Vegetation - Suisun Marsh 2000 [ds161

    Data.gov (United States)

    California Natural Resource Agency — This vegetation mapping project of Suisun Marsh blends ground-based classification, aerial photo interpretation, and GIS editing and processing. The method is based...

  1. Vegetation - Suisun Marsh 1999 [ds160

    Data.gov (United States)

    California Natural Resource Agency — This vegetation mapping project of Suisun Marsh blends ground-based classification, aerial photo interpretation, and GIS editing and processing. The method is based...

  2. Vegetation - Suisun Marsh 2003 [ds162

    Data.gov (United States)

    California Natural Resource Agency — This vegetation mapping project of Suisun Marsh blends ground-based classification, aerial photo interpretation, and GIS editing and processing. The method is based...

  3. Coupled Wave Energy and Erosion Dynamics along a Salt Marsh Boundary, Hog Island Bay, Virginia, USA

    Directory of Open Access Journals (Sweden)

    Anthony M. Priestas

    2015-09-01

    Full Text Available The relationship between lateral erosion of salt marshes and wind waves is studied in Hog Island Bay, Virginia USA, with high-resolution field measurements and aerial photographs. Marsh retreat is compared to wave climate calculated in the bay using the spectral wave-model Simulating Waves Nearshore (SWAN. We confirm the existence of a linear relationship between long-term salt marsh erosion and wave energy, and show that wave power can serve as a good proxy for average salt-marsh erosion rates. At each site, erosion rates are consistent across several temporal scales, ranging from months to decades, and are strongly related to wave power. On the contrary, erosion rates vary in space and weakly depend on the spatial distribution of wave energy. We ascribe this variability to spatial variations in geotechnical, biological, and morphological marsh attributes. Our detailed field measurements indicate that at a small spatial scale (tens of meters, a positive feedback between salt marsh geometry and wave action causes erosion rates to increase with boundary sinuosity. However, at the scale of the entire marsh boundary (hundreds of meters, this relationship is reversed: those sites that are more rapidly eroding have a marsh boundary which is significantly smoother than the marsh boundary of sheltered and slowly eroding marshes.

  4. Monitoring coastal marshes biomass with CASI: a comparison of parametric and non-parametric models

    Science.gov (United States)

    Mo, Y.; Kearney, M.

    2017-12-01

    Coastal marshes are important carbon sinks that face multiple natural and anthropogenic stresses. Optical remote sensing is a powerful tool for closely monitoring the biomass of coastal marshes. However, application of hyperspectral sensors on assessing the biomass of diverse coastal marsh ecosystems is limited. This study samples spectral and biophysical data from coastal freshwater, intermediate, brackish, and saline marshes in Louisiana, and develops parametric and non-parametric models for using the Compact Airborne Spectrographic Imager (CASI) to retrieve the marshes' biomass. Linear models and random forest models are developed from simulated CASI data (48 bands, 380-1050 nm, bandwidth 14 nm). Linear models are also developed using narrowband vegetation indices computed from all possible band combinations from the blue, red, and near infrared wavelengths. It is found that the linear models derived from the optimal narrowband vegetation indices provide strong predictions for the marshes' Leaf Area Index (LAI; R2 > 0.74 for ARVI), but not for their Aboveground Green Biomass (AGB; R2 > 0.25). The linear models derived from the simulated CASI data strongly predict the marshes' LAI (R2 = 0.93) and AGB (R2 = 0.71) and have 27 and 30 bands/variables in the final models through stepwise regression, respectively. The random forest models derived from the simulated CASI data also strongly predict the marshes' LAI and AGB (R2 = 0.91 and 0.84, respectively), where the most important variables for predicting LAI are near infrared bands at 784 and 756 nm and for predicting ABG are red bands at 684 and 670 nm. In sum, the random forest model is preferable for assessing coastal marsh biomass using CASI data as it offers high R2 for both LAI and AGB. The superior performance of the random forest model is likely to due to that it fully utilizes the full-spectrum data and makes no assumption of the approximate normality of the sampling population. This study offers solutions

  5. Salt marsh and seagrass communities of Bakkhali Estuary, Cox's Bazar, Bangladesh

    Science.gov (United States)

    Hena, M. K. Abu; Short, F. T.; Sharifuzzaman, S. M.; Hasan, M.; Rezowan, M.; Ali, M.

    2007-10-01

    The species identification, distribution pattern, density and biomass of salt marsh and seagrass plants with some of the ecological parameters were studied in the Bakkhali river estuary, Cox's Bazar, Bangladesh during the first half of 2006. Two salt marsh species ( Spartina sp. and Imperata cylindrica) and one seagrass species ( Halophila beccarii) were identified during this investigation, providing the first reports of Spartina sp. and H. beccarii in coastal Bangladesh. Seagrass H. beccarii was found in an accreted area and co-existing with salt marsh, and scattered sparsely in the salt marsh habitat and macroalgae Ulva intestinalis. Flowering and fruiting were recorded from the seagrass H. beccarri during January and February. No flowers and fruits were observed for the salt marsh Spartina sp. during the study period. Results showed that the shoot density of Spartina ranged from 400 to 2875 shoots m -2 with the highest total biomass (165.80 g dry weight (DW) m -2) in March. Shoot density of H. beccarii ranged from 2716 to 14320 shoots m -2 in this estuarine coastal environment. The total biomass of seagrass was higher (17.56 g DW m -2) in March compared to the other months. The highest H. beccarii above ground (AG) biomass and below ground (BG) biomass were 9.59 g DW m -2 and 9.42 g DW m -2, respectively. These parameters are comparable with those generally observed for the salt marsh and seagrass species in the other places of the world.

  6. A Climate Change Adaptation Strategy for Management of Coastal Marsh Systems

    Science.gov (United States)

    Sea level rise is causing shoreline erosion, increased coastal flooding, and marsh vulnerability to the impact of storms. Coastal marshes provide flood abatement, carbon and nutrient sequestration, water quality maintenance, and habitat for fish, shellfish, and wildlife, includin...

  7. Effects of nitrogen loading on greenhouse gas emissions in salt marshes

    Science.gov (United States)

    Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Mora, J.; Chen, X.; Carey, J.

    2014-12-01

    Salt marshes play an important role in global and regional carbon and nitrogen cycling. We tested the hypothesis that anthropogenic nitrogen loading alters greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate to triplicate plots bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. Our results will facilitate model development to simulate GHG emissions in coastal wetlands and support methodology development to assess carbon credits in preserving and restoring coastal wetlands.

  8. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes

    Science.gov (United States)

    Leonardi, Nicoletta; Ganju, Neil K.; Fagherazzi, Sergio

    2016-01-01

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.

  9. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes.

    Science.gov (United States)

    Leonardi, Nicoletta; Ganju, Neil K; Fagherazzi, Sergio

    2016-01-05

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.

  10. Evaluation of nekton use and habitat characteristics of restored Louisiana marsh

    Science.gov (United States)

    Thom, C.S.B.; Peyre, M.K.G.L.; Nyman, J.A.

    2004-01-01

    Marsh terracing and coconut fiber mats are two wetland restoration techniques implemented at Sabine National Wildlife Refuge, Louisiana, USA. Using nekton as an indicator of habitat quality, nekton community assemblages were compared between terraced, coconut-matted, unmanaged marsh (restoration goal), and open water (pre-restoration) habitats. Using a throw trap and a 3 m ?? 2 m straight seine, 192 nekton samples were collected over four dates in 2001 and 2002 at all habitats. Nekton abundance was similar at unmanaged marsh (restoration goal), coconut mat, and terrace edge, and significantly higher than at open water (pre-restoration) sites (P Coconut-matted habitat and unmanaged marsh edges had significantly higher numbers of benthic dependent species than terrace edges (P coconut-matted sites. Future restoration projects may evaluate the combined use of coconut mats with terracing projects in order to enhance habitat for benthic dependent nekton.

  11. Mobile telecommunications and health: report of an investigation into an alleged cancer cluster in Sandwell, West Midlands.

    Science.gov (United States)

    Stewart, Antony; Rao, Jammi N; Middleton, John D; Pearmain, Philippa; Evans, Tim

    2012-11-01

    Residents of one street expressed concern about the number of incident cancers, following the installation of a nearby mobile phone base station. The investigation explored whether the base station could be responsible for the cancers. Data were collected from residents' medical records. GPs and oncologists provided further information. Ward-level cancer incidence and mortality data were also obtained, over four three-year time periods. A total of 19 residents had developed cancer. The collection of cancers did not fulfil the criteria for a cancer cluster. Standardized mortality ratios (SMRs) for all malignant neoplasms (excluding non-melanoma skin cancers) in females (1.38 (95% CI, 1.08-1.74)) and all persons (1.27 (CI, 1.06-1.51)) were significantly higher than in the West Midlands during 2001-3. There were no significant differences for colorectal, female breast and prostate cancers, for any time period. Standardized incidence ratios (SIRs) for non-melanoma skin cancers in males and all persons was significantly lower than in the West Midlands during 1999-2001, and significantly lower in males, females and all persons during 2002-4. We cannot conclude that the base station was responsible for the cancers. It is unlikely that information around a single base station can either demonstrate or exclude causality.

  12. Effects of livestock species and stocking density on accretion rates in grazed salt marshes

    NARCIS (Netherlands)

    Nolte, Stefanie; Esselink, Peter; Bakker, Jan P.; Smit, Christian

    2015-01-01

    Coastal ecosystems, such as salt marshes, are threatened by accelerated sea-level rise (SLR). Salt marshes deliver valuable ecosystem services such as coastal protection and the provision of habitat for a unique flora and fauna. Whether salt marshes in the Wadden Sea area are able to survive

  13. Greenhouse gas fluxes from salt marshes exposed to chronic nutrient enrichment

    Science.gov (United States)

    Chmura, Gail L.; Kellman, Lisa; van Ardenne, Lee; Guntenspergen, Glenn R.

    2016-01-01

    We assessed the impact of nutrient additions on greenhouse gas fluxes using dark static chambers in a microtidal and a macrotidal marsh along the coast of New Brunswick, Canada approximately monthly over a year. Both were experimentally fertilized for six years with varying levels of N and P. For unfertilized, N and NPK treatments, average yearly CO2 emissions (which represent only respiration) at the microtidal marsh (13, 19, and 28 mmoles CO2 m-2 hr-1, respectively) were higher than at the macrotidal marsh (12, 15, and 19 mmoles m-2 hr-1, respectively, with a flux under the additional high N/low P treatment of 21 mmoles m-2 hr-1). Response of CH4 to fertilization was more variable. At the macrotidal marsh average yearly fluxes were 1.29, 1.26, and 0.77 μmol CH4 m-2 hr-1 with control, N, and NPK treatments, respectively and 1.21 μmol m-2 hr-1 under high N/low P treatment. At the microtidal marsh CH4fluxes were 0.23, 0.16, and -0.24 μmol CH4 m-2 hr-1 in control, N, and NPK and treatments, respectively. Fertilization changed soils from sinks to sources of N2O. Average yearly N2O fluxes at the macrotidal marsh were -0.07, 0.08, and 1.70, μmol N2O m-2 hr-1 in control, N, NPK and treatments, respectively and 0.35 μmol m-2 hr-1 under high N/low P treatment. For the control, N, and NPK treatments at the microtidal marsh N2O fluxes were -0.05, 0.30, and 0.52 μmol N2O m-2 hr-1, respectively. Our results indicate that N2O fluxes are likely to vary with the source of pollutant nutrients but emissions will be lower if N is not accompanied by an adequate supply of P (e.g., atmospheric deposition vs sewage or agricultural runoff). With chronic fertilization the global warming potential of the increased N2O emissions may be enough to offset the global cooling potential of the C sequestered by salt marshes.

  14. Breeding ecology and nesting habitat associations of five marsh bird species in western New York

    Science.gov (United States)

    Lor, S.; Malecki, R.A.

    2006-01-01

    Nesting habitats and nest success of five species of marsh birds were studied during 1997 and 1998 at the Iroquois National Wildlife Refuge (NWR) and the adjacent Oak Orchard and Tonawanda State Wildlife Management Areas (WMA) located in western New York. Nest searches located 18 American Bittern (Botaurus lentiginosus), 117 Least Bittern (Ixobrychus exilis), 189 Pied-billed Grebe (Podilymbus podiceps), 23 Sora (Porzana carolina), and 72 Virginia Rail (Rallus limicola) nests. Average nest densities in 1998, our best nest searching year, ranged from 0.01/ha for Soras (N = 8) to 0.28/ha for Pied-billed Grebes (N = 160). Mayfield nest success estimates for Least Bittern were 80% (N = 16) in 1997 and 46% (N = 37) in 1998. Nest success estimates were 72% (N = 55) for Pied-billed Grebe, 43% (N = 6) for Sora, and 38% (N = 20) for Virginia Rail. Nests of all five species were located in ???70% emergent vegetation with a mean water depth of 24-56 cm and an average vegetation height that ranged from 69-133 cm. Logistic regression models were developed for each species using habitat variables at nest and random site locations. Each model was ranked with Akaike's Information Criterion for small sample size (AICc). In general, our best models indicated that increased emergent vegetation and horizontal cover with shallow water depths improved the odds of encountering marsh bird nests in the wetlands of western New York. We suggest that managing wetlands as a complex, at different stages of succession, would best benefit marsh bird species.

  15. The contribution of mangrove expansion to salt marsh loss on the Texas Gulf Coast.

    Science.gov (United States)

    Armitage, Anna R; Highfield, Wesley E; Brody, Samuel D; Louchouarn, Patrick

    2015-01-01

    Landscape-level shifts in plant species distribution and abundance can fundamentally change the ecology of an ecosystem. Such shifts are occurring within mangrove-marsh ecotones, where over the last few decades, relatively mild winters have led to mangrove expansion into areas previously occupied by salt marsh plants. On the Texas (USA) coast of the western Gulf of Mexico, most cases of mangrove expansion have been documented within specific bays or watersheds. Based on this body of relatively small-scale work and broader global patterns of mangrove expansion, we hypothesized that there has been a recent regional-level displacement of salt marshes by mangroves. We classified Landsat-5 Thematic Mapper images using artificial neural networks to quantify black mangrove (Avicennia germinans) expansion and salt marsh (Spartina alterniflora and other grass and forb species) loss over 20 years across the entire Texas coast. Between 1990 and 2010, mangrove area grew by 16.1 km(2), a 74% increase. Concurrently, salt marsh area decreased by 77.8 km(2), a 24% net loss. Only 6% of that loss was attributable to mangrove expansion; most salt marsh was lost due to conversion to tidal flats or water, likely a result of relative sea level rise. Our research confirmed that mangroves are expanding and, in some instances, displacing salt marshes at certain locations. However, this shift is not widespread when analyzed at a larger, regional level. Rather, local, relative sea level rise was indirectly implicated as another important driver causing regional-level salt marsh loss. Climate change is expected to accelerate both sea level rise and mangrove expansion; these mechanisms are likely to interact synergistically and contribute to salt marsh loss.

  16. Summary of intrinsic and extrinsic factors affecting detection probability of marsh birds

    Science.gov (United States)

    Conway, C.J.; Gibbs, J.P.

    2011-01-01

    Many species of marsh birds (rails, bitterns, grebes, etc.) rely exclusively on emergent marsh vegetation for all phases of their life cycle, and many organizations have become concerned about the status and persistence of this group of birds. Yet, marsh birds are notoriously difficult to monitor due to their secretive habits. We synthesized the published and unpublished literature and summarized the factors that influence detection probability of secretive marsh birds in North America. Marsh birds are more likely to respond to conspecific than heterospecific calls, and seasonal peak in vocalization probability varies among co-existing species. The effectiveness of morning versus evening surveys varies among species and locations. Vocalization probability appears to be positively correlated with density in breeding Virginia Rails (Rallus limicola), Soras (Porzana carolina), and Clapper Rails (Rallus longirostris). Movement of birds toward the broadcast source creates biases when using count data from callbroadcast surveys to estimate population density. Ambient temperature, wind speed, cloud cover, and moon phase affected detection probability in some, but not all, studies. Better estimates of detection probability are needed. We provide recommendations that would help improve future marsh bird survey efforts and a list of 14 priority information and research needs that represent gaps in our current knowledge where future resources are best directed. ?? Society of Wetland Scientists 2011.

  17. In situ burning of oil in coastal marshes. 1. Vegetation recovery and soil temperature as a function of water depth, oil type, and marsh type.

    Science.gov (United States)

    Lin, Qianxin; Mendelssohn, Irving A; Bryner, Nelson P; Walton, William D

    2005-03-15

    In-situ burning of oiled wetlands potentially provides a cleanup technique that is generally consistent with present wetland management procedures. The effects of water depth (+10, +2, and -2 cm), oil type (crude and diesel), and oil penetration of sediment before the burn on the relationship between vegetation recovery and soil temperature for three coastal marsh types were investigated. The water depth over the soil surface during in-situ burning was a key factor controlling marsh plant recovery. Both the 10- and 2-cm water depths were sufficient to protect marsh vegetation from burning impacts, with surface soil temperatures of fire significantly impeded the post-burn recovery of Spartina alterniflora and Sagittaria lancifolia but did not detrimentally affect the recovery of Spartina patens and Distichlis spicata. Oil type (crude vs diesel) and oil applied to the marsh soil surface (0.5 L x m(-2)) before the burn did not significantly affect plant recovery. Thus, recovery is species-specific when no surface water exists. Even water at the soil surface will most likely protect wetland plants from burning impact.

  18. DENITRIFICATION ENZYME ACTIVITY OF FRINGE SALT MARSHES IN NEW ENGLAND (USA)

    Science.gov (United States)

    Coastal salt marshes are a buffer between the uplands and adjacent coastal waters in New England (USA). With increasing N loads from developed watersheds, salt marshes could play an important role in the water quality maintenance of coastal waters. In this study we examined seaso...

  19. The structure of salt marsh soil mesofauna food webs - The prevalence of disturbance.

    Science.gov (United States)

    Haynert, Kristin; Kiggen, Mirijam; Klarner, Bernhard; Maraun, Mark; Scheu, Stefan

    2017-01-01

    Mesofauna taxa fill key trophic positions in soil food webs, even in terrestrial-marine boundary habitats characterized by frequent natural disturbances. Salt marshes represent such boundary habitats, characterized by frequent inundations increasing from the terrestrial upper to the marine pioneer zone. Despite the high abundance of soil mesofauna in salt marshes and their important function by facilitating energy and carbon flows, the structure, trophic ecology and habitat-related diet shifts of mesofauna species in natural salt marsh habitats is virtually unknown. Therefore, we investigated the effects of natural disturbance (inundation frequency) on community structure, food web complexity and resource use of soil mesofauna using stable isotope analysis (15N, 13C) in three salt marsh zones. In this intertidal habitat, the pioneer zone is exposed to inundations twice a day, but lower and upper salt marshes are less frequently inundated based on shore height. The mesofauna comprised 86 species / taxa dominated by Collembola, Oribatida and Mesostigmata. Shifts in environmental disturbances influenced the structure of food webs, diversity and density declined strongly from the land to the sea pointing to the importance of increasing levels of inundation frequency. Accordingly, the reduced diversity and density was associated by a simplification of the food web in the pioneer zone as compared to the less inundated lower and upper salt marsh with a higher number of trophic levels. Strong variations in δ15N signatures demonstrated that mesofauna species are feeding at multiple trophic levels. Primary decomposers were low and most mesofauna species functioned as secondary decomposers or predators including second order predators or scavengers. The results document that major decomposer taxa, such as Collembola and Oribatida, are more diverse than previously assumed and predominantly dwell on autochthonous resources of the respective salt marsh zone. The results further

  20. Does vegetation prevent wave erosion of salt marsh edges?

    Science.gov (United States)

    Feagin, R A; Lozada-Bernard, S M; Ravens, T M; Möller, I; Yeager, K M; Baird, A H

    2009-06-23

    This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves.

  1. Nitrogen processing in a tidal freshwater marsh: a whole ecosystem 15N labeling study

    NARCIS (Netherlands)

    Gribsholt, B.; Boschker, H.T.S.; Struyf, E.; Andersson, M.G.I.; Tramper, A.; de Brabandere, L.; van Damme, S.; Brion, N.; Meire, P.; Dehairs, F.; Middelburg, J.J.; Heip, C.H.R.

    2005-01-01

    We quantified the fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrientrich Scheldt River in a whole-ecosystem 15N labeling experiment. 15N-NH4+ was added to the floodwater entering a 3,477 14 m2 tidal marsh area, and marsh ammonium processing and

  2. Geomorphic and ecological effects of Hurricanes Katrina and Rita on coastal Louisiana marsh communities

    Science.gov (United States)

    Piazza, Sarai C.; Steyer, Gregory D.; Cretini, Kari F.; Sasser, Charles E.; Visser, Jenneke M.; Holm, Guerry O.; Sharp, Leigh A.; Evers, D. Elaine; Meriwether, John R.

    2011-01-01

    Hurricanes Katrina and Rita made landfall in 2005, subjecting the coastal marsh communities of Louisiana to various degrees of exposure. We collected data after the storms at 30 sites within fresh (12), brackish/intermediate (12), and saline (6) marshes to document the effects of saltwater storm surge and sedimentation on marsh community dynamics. The 30 sites were comprised of 15 pairs. Most pairs contained one site where data collection occurred historically (that is, prestorms) and one Coastwide Reference Monitoring System site. Data were collected from spring 2006 to fall 2007 on vegetative species composition, percentage of vegetation cover, aboveground and belowground biomass, and canopy reflectance, along with discrete porewater salinity, hourly surface-water salinity, and water level. Where available, historical data acquired before Hurricanes Katrina and Rita were used to compare conditions and changes in ecological trajectories before and after the hurricanes. Sites experiencing direct and indirect hurricane influences (referred to in this report as levels of influence) were also identified, and the effects of hurricane influence were tested on vegetation and porewater data. Within fresh marshes, porewater salinity was greater in directly impacted areas, and this heightened salinity was reflected in decreased aboveground and belowground biomass and increased cover of disturbance species in the directly impacted sites. At the brackish/intermediate marsh sites, vegetation variables and porewater salinity were similar in directly and indirectly impacted areas, but porewater salinity was higher than expected throughout the study. Interestingly, directly impacted saline marsh sites had lower porewater salinity than indirectly impacted sites, but aboveground biomass was greater at the directly impacted sites. Because of the variable and site-specific nature of hurricane influences, we present case studies to help define postdisturbance baseline conditions in

  3. Salt marsh stability and patterns of sedimentation across a backbarrier platform

    DEFF Research Database (Denmark)

    Bartholdy, Anders; Bartholdy, Jesper; Kroon, Aart

    2010-01-01

    Long term observations of clay thicknesses from 1949 to 2007 and measurements of the bulk dry density of salt marsh on the backbarrier of Skallingen (west Denmark) formed the basis of constructing a space distributed model of salt marsh deposition. The deposition potential (an empirical constant, ß...

  4. Alternative nitrate reduction pathways in experimentally fertilized New England salt marshes

    DEFF Research Database (Denmark)

    Uldahl, Anne; Banta, Gary Thomas; Boegh, Eva

    the ecosystem in the form of gaseous N2, while the last process transforms of NO3- to another biologically available form, NH4+, and thus merely recycles N. Salt marshes are important ecosystems for the cycling, retention and removal of biologically available N transported from land to the oceans. We used...... ongoing ecosystem level nutrient additions experiments in two New England salt marshes, Plum Island Sound (NO3- additions since 2003) and Great Sippewissett Marsh (fertilizer additions since the 1970's) to examine the relative importance of these NO3- reduction pathways in salt marshes. Sediments from...... several experimental (and unmanipulated) sites were collected during the late summer/fall of 2009 and summer 2010 to measure the potential rates of NO3- reduction in sediment slurries enriched with NO3- and 15NO3- added as a tracer. The resulting 15N-labeled products (30N2, 29N2 and 15NH4+) were analyzed...

  5. Quantifying Trophic Interactions and Carbon Flow in Louisiana Salt Marshes Using Multiple Biomarkers

    Science.gov (United States)

    Polito, M. J.; Lopez-Duarte, P. C.; Olin, J.; Johnson, J. J.; Able, K.; Martin, C. W.; Fodrie, J.; Hooper-Bui, L. M.; Taylor, S.; Stouffer, P.; Roberts, B. J.; Rabalais, N. N.; Jensen, O.

    2017-12-01

    Salt marshes are critical habitats for many species in the northern Gulf of Mexico. However, given their complex nature, quantifying trophic linkages and the flow of carbon through salt marsh food webs is challenging. This gap in our understanding of food web structure and function limits our ability to evaluate the impacts of natural and anthropogenic stressors on salt marsh ecosystems. For example, 2010 Deepwater Horizon (DWH) oil spill had the potential to alter trophic and energy pathways. Even so, our ability to evaluate its effects on Louisiana salt marsh food webs was limited by a poor basis for comparison of the pre-spill baseline food web. To be better equipped to measure significant alterations in salt marsh ecosystems in the future, we quantified trophic interactions at two marsh sites in Barataria Bay, LA in May and October of 2015. Trophic structure and carbon flow across 52 species of saltmarsh primary producers and consumers were examined through a combination of three approaches: bulk tissue stable isotope analysis (δ13C, δ15N, δ34S), dietary fatty acid analysis (FAA), and compound-specific stable isotope analysis of essential amino acids (δ13C EAA). Bulk stable isotope analysis indicated similar trophic diversity between sites and seasons with the use of aquatic resources increasing concomitantly with trophic level. FAA and δ13C EAA biomarkers revealed that marsh organisms were largely divided into two groups: those that primarily derive carbon from terrestrial C4 grasses, and those that predominately derive carbon from a combination of phytoplankton and benthic microalgal sources. Differences in trophic structure and carbon flow were minimal between seasons and sites that were variably impacted by the DWH spill. These data on salt marsh ecosystem structure will be useful to inform future injury assessments and restoration initiatives.

  6. Salt marsh recovery from a crude oil spill: Vegetation, oil weathering, and response

    International Nuclear Information System (INIS)

    Hoff, R.Z.; Shigenaka, G.; Henry, C.B. Jr.

    1993-01-01

    When a spill of Prudhoe Bay crude oil covered a fringing Salicornia virginica marsh in Fidalgo Bay, Washington (northern Puget Sound) in February 1991, response personnel used several low-impact techniques to remove oil from the marsh, and minimized access by cleanup workers. Following the response, a monitoring program was established to track marsh recovery, and to document the effectiveness of the response techniques used and their impacts on the marsh. Through monthly sampling over a 16-month period, vegetative growth was monitored and chemical degradation of remaining oil was tracked. Sampling was conducted along transects located in four areas affected in different ways by the spill, including an oiled, trampled section; an oiled, vacuumed section; and an oiled, washed, and vacuumed section. In addition, a control transect was established in an unoiled adjacent marsh. The study included both biological and chemical components. Biological measurements included percent cover of live vegetation (sampled monthly) and below-ground plant biomass (sampled at the beginning of each growing season in April 1991 and April 1992). Sediment samples included surface sediment (monthly) and core samples collected at the beginning and end of the growing seasons. Sediment samples were analyzed using gas chromatography/mass spectroscopy, and indicator compounds were tracked to determine rates of oil degradation. Results from 16 months of post-spill monitoring show that foot trampling was most detrimental to marsh plants, while washing with vacuuming removed the most oil and minimized adverse impacts to vegetation. Dense clay substrate helped prevent oil from penetrating the sediment, thus minimizing acute toxic effects from oil exposure to marsh plant rootstock. By the second growing season post-spill, Salicornia and other marsh plants were growing in all areas except one heavily oiled patch

  7. Carbon Dioxide and Methane Emissions from Diverse Zones of a California Salt Marsh

    Science.gov (United States)

    Wang, F.; King, J. Y.

    2016-12-01

    With high primary productivity and low organic matter decomposition rates, salt marshes sequester carbon from the atmosphere and contribute to mitigation of climate change. However, the role of wetlands in carbon sequestration is offset by CO2 and CH4 emissions whose magnitudes remain coarsely constrained. To better understand the spatiotemporal dynamics of gaseous carbon fluxes from marsh soils in a Mediterranean climate, we collected air and soil samples over the course of 10 months at Carpinteria Salt Marsh Reserve (CSMR) located in the County of Santa Barbara, California. The CSMR consists of four distinct zones characterized by differences in elevation, tidal regime, and vegetation. Twelve static chambers were deployed among two lower marsh zones, a salt flat, and a marsh-upland transition zone for fortnightly flux measurements from September, 2015 to May, 2016. In August, 2015 and June, 2016, soil cores up to 50 cm deep were extracted near the chambers, segmented by depth, and analyzed for soil moisture, bulk density, EC, pH, organic/inorganic carbon, and total nitrogen content. The gaseous carbon fluxes showed significant spatiotemporal variability, and soil properties differed noticeably by zone and by depth. Integrated over the study period, the marsh-upland transition zone had the highest CO2 fluxes at 292 g C/m2, followed closely by the lower marsh zones (271 g C/m2 and 189 g C/m2), which were one order of magnitude higher than the CO2 fluxes from the salt flat (23 g C/m2). Seasonally, CO2 fluxes were 2.5 to 3.5 times higher during the warmer months (Sept - Oct, Mar - May) than the colder months (Nov - Feb) across all zones. The CH4 fluxes were more temporally heterogeneous, but overall the CH4 emissions from the lower marsh zones (1.37 g C/m2 and 0.41 g C/m2) surpassed those from the salt flat (0.054 g C/m2) by an order of magnitude, and the marsh-upland transition zone was a net methane sink (-0.029 g C/m2). Our results show that soil gaseous carbon

  8. Gulf-Wide Information System, Environmental Sensitivity Index Marsh, Geographic NAD83, LDWF (2001) [esi_fresh_marsh_LDWF_2001

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains Environmental Sensitivity Index (ESI) fresh marsh data of coastal Louisiana. The ESI is a classification and ranking system, which...

  9. Rates and probable causes of freshwater tidal marsh failure, Potomac River Estuary, Northern Virginia, USA

    Science.gov (United States)

    Litwin, Ronald J.; Smoot, Joseph P.; Pavich, Milan J.; Markewich, Helaine Walsh; Oberg, Erik T.; Steury, Brent W.; Helwig, Ben; Santucci, Vincent L.; Sanders, Geoffrey

    2013-01-01

    Dyke Marsh, a distal tidal marsh along the Potomac River estuary, is diminishing rapidly in areal extent. This study documents Dyke Marsh erosion rates from the early-1860s to the present during pre-mining, mining, and post-mining phases. From the late-1930s to the mid-1970s, Dyke Marsh and the adjacent shallow riverbottom were mined for gravel, resulting in a ~55 % initial loss of area. Marsh loss continued during the post-mining phase (1976–2012). Causes of post-mining loss were unknown, but were thought to include Potomac River flooding. Post-mining areal-erosion rates increased from 0.138 ha yr−1 (~0.37 ac yr−1) to 0.516 ha yr−1(~1.67 ac yr−1), and shoreline-erosion rates increased from 0.76 m yr−1 (~2.5 ft yr−1) to 2.60 m yr−1 (~8.5 ft yr−1). Results suggest the accelerating post-mining erosion reflects a process-driven feedback loop, enabled by the marsh's severely-altered geomorphic and hydrologic baseline system; the primary post-mining degradation process is wave-induced erosion from northbound cyclonic storms. Dyke Marsh erosion rates are now comparable to, or exceed, rates for proximal coastal marshes in the same region. Persistent and accelerated erosion of marshland long after cessation of mining illustrates the long-term, and potentially devastating, effects that temporally-restricted, anthropogenic destabilization can have on estuarine marsh systems.

  10. Contribution of Cultural Eutrophication to Marsh Loss in Jamaica Bay (NY)

    Science.gov (United States)

    Loss of salt marsh area in the Jamaica Bay Estuary (NY) has accelerated in recent years, with loss rates as high as 45 acres per year. A contributing factor to this acceleration is likely cultural eutrophication due to over 6 decades of sewage effluent inputs. We examined marsh...

  11. The American chestnut and fire: 6-year research results

    Science.gov (United States)

    Stacy L. Clark; Callie J. Schweitzer; Mike R. Saunders; Ethan P. Belair; Scott J. Torreano; Scott E. Schlarbaum

    2014-01-01

    American chestnut [Castanea dentata Marsh. (Borkh.)] is an iconic species with important ecological and utilitarian values, but was decimated by the mid-20th century by exotic fungal species fromAsia. Successful restoration will require sustainable silvicultural methods to maximize survival and afford chestnut a competitive advantage over natural vegetation. The study...

  12. Specificity of salt marsh diazotrophs for vegetation zones and plant hosts

    Directory of Open Access Journals (Sweden)

    Debra Aline Davis

    2012-03-01

    Full Text Available Salt marshes located on the east coast of temperate North America are highly productive, typically nitrogen-limited, and support diverse assemblages of nitrogen fixing (diazotrophic bacteria. The distributions of these diazotrophs are strongly influenced by plant host and abiotic environmental parameters. Crab Haul Creek Basin, North Inlet, SC, USA is a tidally dominated marsh that displays discrete plant zones distributed along an elevation gradient from the tidal creek bank to the terrestrial forest. These zones are defined by gradients of abiotic environmental variables, particularly salinity and sulfide. DGGE fingerprinting and phylogenetic analyses of recovered sequences demonstrated that the distributions of some diazotrophs indicate plant host specificity and that diazotroph assemblages across the marsh gradient are heavily influenced by edaphic conditions. Broadly distributed diazotrophs capable of maintaining populations in all environmental conditions across the gradient are also present in these assemblages. Parsimony test results confirm that diazotroph assemblages in different plant zones are significantly (p<0.01 different across the marsh landscape. Results also indicated that diazotroph assemblages associated with different plant hosts growing in the same area of the marsh were structurally similar confirming the influence of edaphic parameters on these assemblages. Principal Component Analysis of DGGE gel banding patterns confirmed these results. This article reviews and analyzes data from North Inlet Estuary, addressing diazotroph assemblage structure and the influence of plant host and environmental conditions. New data demonstrate the heterogeneity of salt marsh rhizosphere microenvironments, and corroborate previous findings from different plant hosts growing at several locations within this estuary. These data support the hypothesis that the biogeography of microorganisms is non-random and is partially driven by

  13. Service experience with AISI type 316 steel components in CEGB Midlands Region power plant

    International Nuclear Information System (INIS)

    Plastow, B.; Bagnall, B.I.; Yeldham, D.E.

    1979-01-01

    The service performance of AISI Type 316 steel components in sections up to 100 mm thick in Power Plant of the Midlands Region of the C.E.G.B. is reviewed. A comparison is drawn between the satisfactory performance of components whose dimensional stability is not critical and the difficulties experienced when rapid rates of change of temperature cause distortion in thick section components. Weldment manufacture and performance are reviewed and both are considered to be satisfactory. In general the material has performed well and the difficulties due to distortion have been overcome by imposing operating regimes which limit rates of temperature change. (author)

  14. Trophic shift in young-of-the-year Mugilidae during salt-marsh colonization.

    Science.gov (United States)

    Lebreton, B; Richard, P; Guillou, G; Blanchard, G F

    2013-04-01

    This study investigated the trophic shift of young-of-the-year (YOY) thinlip grey mullet Liza ramada and golden grey mullet Liza aurata during their recruitment in a salt marsh located on the European Atlantic Ocean coast. Stable-isotope signatures (δ(13) C and δ(15) N) of the fishes followed a pattern, having enrichments in (13) C and (15) N with increasing fork length (LF ): δ(13) C in fishes  30 mm δ(13) C ranged from -15.8 to -12.7‰, closer to the level in salt-marsh food resources. Large differences between the δ(15) N values of mugilids and those of food sources (6·0‰ on average) showed that YOY are secondary consumers, similar to older individuals, when feeding in the salt marsh. YOY mugilids shift from browsing on pelagic prey to grazing on benthic resources from the salt marsh before reaching 30 mm LF. The results highlight the role of European salt marshes as nurseries for juvenile mugilids. © 2013 The Authors. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.

  15. Monitoring for bioremediation efficacy: The marrow marsh experience

    International Nuclear Information System (INIS)

    Nadeau, R.; Singhvi, R.; Ryabik, J.; Lin, Yihua; Syslo, J.

    1993-01-01

    The US Environmental Protection Agency's Environmental Response Team analyzed samples taken from Marrow Marsh, Galveston Bay, Texas, to assess the efficacy of a bioremediation effort in the marsh following the Apex barges spill on July 28, 1990. Samples from the marsh had been collected over a 96-hour period following the first application of the bioremediation agent and then 25 days after the second application, which occurred 8 days after the first. Results of sample analyses to evaluate changes in the chemical characteristics of spilled oil failed to show evidence of oil degradation during the 96 hours after the initial treatment, but did show evidence of degradation 25 days after the second treatment-although differences between samples from treated and untreated sites were not evident. Because control areas had not been maintained after the second application, contamination by the bioremediation agent of previously untreated (control) areas may have occurred, perhaps negating the possibility of detecting differences between treated and control areas. Better preparedness to implement bioremediation and conduct monitoring might have increased the effectiveness of the monitoring effort

  16. Effects of bryophytes on succession from alkaline marsh to Sphagnum bog

    Energy Technology Data Exchange (ETDEWEB)

    Glime, J.M.; Wetzel, R.G.; Kennedy, B.J.

    1982-10-01

    The alkaline eastern marsh of Lawrence Lake, a marl lake in southwestern Michigan, was sampled by randomly placed line transects to determine the bryophyte cover and corresponding vascular plant zones. Cluster analysis indicated three distinct bryophyte zones which correspond with the recognized vascular plant zones. Mosses occupied over 50% of the surface in some areas. Invasion of Sphagnum, vertical zonation of the mosses on hummocks, zonation with distance from the lake, the abundance of non-Sphagnum moss hummocks, and the ability of the non-Sphagnum species to lower the pH of marsh water during laboratory incubations are evidence that non-Sphagnum mosses facilitate succession from alkaline marsh to Sphagnum bog.

  17. Effects of gender and regional dialect on prosodic patterns in American English

    Science.gov (United States)

    Clopper, Cynthia G.; Smiljanic, Rajka

    2011-01-01

    While cross-dialect prosodic variation has been well established for many languages, most variationist research on regional dialects of American English has focused on the vowel system. The current study was designed to explore prosodic variation in read speech in two regional varieties of American English: Southern and Midland. Prosodic dialect variation was analyzed in two domains: speaking rate and the phonetic expression of pitch movements associated with accented and phrase-final syllables. The results revealed significant effects of regional dialect on the distributions of pauses, pitch accents, and phrasal-boundary tone combinations. Significant effects of talker gender were also observed on the distributions of pitch accents and phrasal-boundary tone combinations. The findings from this study demonstrate that regional and gender identity features are encoded in part through prosody, and provide further motivation for the close examination of prosodic patterns across regional and social varieties of American English. PMID:21686317

  18. Effects of Extreme Events on Arsenic Cycling in Salt Marshes

    Science.gov (United States)

    Northrup, Kristy; Capooci, Margaret; Seyfferth, Angelia L.

    2018-03-01

    Extreme events such as storm surges, intense precipitation, and supermoons cause anomalous and large fluctuations in water level in tidal salt marshes, which impacts the sediment biogeochemistry that dictates arsenic (As) cycling. In addition to changes in water level, which impacts soil redox potential, these extreme events may also change salinity due to freshwater inputs from precipitation or saltwater inputs due to surge. It is currently unknown how As mobility in tidal salt marshes will be impacted by extreme events, as fluctuations in salinity and redox potential may act synergistically to mobilize As. To investigate impacts of extreme events on As cycling in tidal salt marshes, we conducted a combined laboratory and field investigation. We monitored pore water and soil samples before, during, and after two extreme events: a supermoon lunar eclipse followed by a storm surge and precipitation induced by Hurricane Joaquin in fall 2015 at the St. Jones Reserve in Dover, Delaware, a representative tidal salt marsh in the Mid-Atlantic United States. We also conducted soil incubations of marsh sediments in batch and in flow-through experiments in which redox potential and/or salinity were manipulated. Field investigations showed that pore water As was inversely proportional to redox potential. During the extreme events, a distinct pulse of As was observed in the pore water with maximum salinity. Combined field and laboratory investigations revealed that this As pulse is likely due to rapid changes in salinity. These results have implications for As mobility in the face of extreme weather variability.

  19. Below the disappearing marshes of an urban estuary: historic nitrogen trends and soil structure

    Science.gov (United States)

    Wigand, Cathleen; Roman, Charles T.; Davey, Earl; Stolt, Mark; Johnson, Roxanne; Hanson, Alana; Watson, Elizabeth B.; Moran, S. Bradley; Cahoon, Donald R.; Lynch, James C.; Rafferty, Patricia

    2014-01-01

    Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13 ha/yr, and multiple stressors (e.g., wastewater inputs, dredging activities, groundwater removal, and global warming) may be contributing to marsh losses. Among these stressors, wastewater nutrients are suspected to be an important contributing cause of marsh deterioration. We used census data, radiometric dating, stable nitrogen isotopes, and soil surveys to examine the temporal relationships between human population growth and soil nitrogen; and we evaluated soil structure with computer-aided tomography, surface elevation and sediment accretion trends, carbon dioxide emissions, and soil shear strength to examine differences among disappearing (Black Bank and Big Egg) and stable marshes (JoCo). Radiometric dating and nitrogen isotope analyses suggested a rapid increase in human wastewater nutrients beginning in the late 1840s, and a tapering off beginning in the 1930s when wastewater treatment plants (WWTPs) were first installed. Current WWTPs nutrient loads to Jamaica Bay are approximately 13 995 kg N/d and 2767 kg P/d. At Black Bank, the biomass and abundance of roots and rhizomes and percentage of organic matter on soil were significantly lower, rhizomes larger in diameter, carbon dioxide emission rates and peat particle density significantly greater, and soil strength significantly lower compared to the stable JoCo Marsh, suggesting Black Bank has elevated decomposition rates, more decomposed peat, and highly waterlogged peat. Despite these differences, the rates of accretion and surface elevation change were similar for both marshes, and the rates of elevation change approximated the long term relative rate of sea level rise estimated from tide gauge data at nearby Sandy Hook, New Jersey. We hypothesize that Black Bank marsh kept pace with sea level rise by the accretion of material on the marsh surface, and the maintenance of soil volume through production of

  20. Modified Marsh Classification of the Duodenal Biopsies of a Large Database Covering 10 Years

    Directory of Open Access Journals (Sweden)

    Cansu Abayli

    2014-02-01

    Full Text Available Purpose: Celiac is an autoimmune disease caused by of gluten proteins which can be found in multi-grain food like wheat, barley and oat. The disease affects more than 1% of population and characterized by intestinal inflammation. In celiac disease, mucosal damage is a dynamic process. It is shown that it has autoimmune components. It is also T-Cell mediated and can be categorised as a chronic inflammatory disease. The purpose of this study is to make modified Marsh classification of the duodenal biopsies that came to our department in the 10 years. The study deals with reassessment of all events and uncovering the low graded events that were not diagnosed. Material and Methods: 467 biopsies (diagnosed between 2001 and 2011 at the Cukurova University, Faculty of Medicine, Department of Pathology were taken and analyzed by two pathologists. Each sample was reevaluated without taking the previous reports into consideration and scored by using modified Marsh classification. Results: According to Modified Marsh Classification total of 48 cases were diagnosed as Type 1. Total of 6 cases according to Modified Marsh Classification was diagnosed as Type 2. Total of 11 cases according to Modified Marsh Classification was diagnosed as Type 3a. Total of 5 cases, according to Modified Marsh Classification, was diagnosed as Type 3b. Total of 6 cases according to Modified Marsh Classification was diagnosed as Type 3c. Conclusion: As a result of this study, it has been found that Modified Marsh Classification is a very important standardization tool for detection of suspicious duodenal biopsies and for early case examinations.

  1. The Role of Tidal Marsh Restoration in Fish Management in the San Francisco Estuary

    Directory of Open Access Journals (Sweden)

    Bruce Herbold

    2014-03-01

    Full Text Available   Tidal marsh restoration is an important management issue in the San Francisco Estuary (estuary. Restoration of large areas of tidal marsh is ongoing or planned in the lower estuary (up to 6,000 ha, Callaway et al. 2011. Large areas are proposed for restoration in the upper estuary under the Endangered Species Act biological opinions (3,237 ha and the Bay Delta Conservation Plan (26,305 ha. In the lower estuary, tidal marsh has proven its value to a wide array of species that live within it (Palaima 2012. In the Sacramento–San Joaquin Delta (Delta, one important function ascribed to restoration of freshwater tidal marshes is that they make large contributions to the food web of fish in open waters (BDCP 2013. The Ecosystem Restoration Program ascribed a suite of ecological functions to tidal marsh restoration, including habitat and food web benefits to native fish (CDFW 2010. This background was the basis for a symposium, Tidal Marshes and Native Fishes in the Delta: Will Restoration Make a Difference? held at the University of California, Davis, on June 10, 2013. This paper summarizes conclusions the authors drew from the symposium. 

  2. Refractory organic matter in coastal salt marshes-effect on C sequestration calculations.

    Science.gov (United States)

    Leorri, Eduardo; Zimmerman, Andrew R; Mitra, Siddhartha; Christian, Robert R; Fatela, Francisco; Mallinson, David J

    2018-08-15

    The age and ability of salt marshes to accumulate and sequester carbon is often assessed using the carbon isotopic signatures (Δ 14 C and δ 13 C) of sedimentary organic matter. However, transfers of allochthonous refractory carbon (C RF ) from the watershed to marshes would not represent new C sequestration. To better understand how refractory carbon (C RF ) inputs affect assessments of marsh age and C sequestration, Δ 14 C and δ 13 C of both total organic carbon (TOC), C RF , and non-C RF organic matter fractions were measured in salt marshes from four contrasting systems on the North Atlantic coast. To our knowledge, no salt marsh sediment study has considered refractory or allochthonous carbon in carbon budget calculations or the impact on chronologies. Stable and radiogenic isotope data suggest that while TOC was dominated by autochthonous plant inputs, C RF was dominated by locally recycled or allochthonous C, the delivery of which was controlled by the size and slope of each watershed. Steep-gradient rivers analyzed delivered Δ 14 C-depleted C RF to their estuarine marshes, while the site located in the low-gradient river was associated with larger C RF content. Finally, the marsh isolated from riverine input contained the least fraction of TOC as C RF . Laterally transported C RF caused only a small offset in Δ 14 C in relation to TOC in low-gradient systems (average Δ 14 C offset was -44.4 and -24.2‰ at each location). However, the presence of allochthonous Δ 14 C-depleted C RF in sediments of steep-gradient rivers led to large overestimates of the time of organic matter deposition (i.e. apparent age was older than the 'true' time of deposition) (Δ 14 C offset ranged from -170.6 to -528.9‰). Further, reliance on TOC or loss on ignition analyses to calculate C sequestration by marshes might produce overestimates of at least as much as 10 to 20% since neither account for the lateral transport of allochthonous carbon. Copyright © 2018 Elsevier B

  3. Import and export fluxes of macrozooplankton are taxa- and season-dependent at Jiuduansha marsh, Yangtze River estuary

    Science.gov (United States)

    Qin, Haiming; Sheng, Qiang; Chu, Tianjiang; Wang, Sikai; Wu, Jihua

    2015-09-01

    Macrozooplankton may play important roles in influencing nutrient exchange between salt marsh and nearby estuarine ecosystems through predator-prey interactions and their transport by tidal flows. In this study, macrozooplankton transport through year-round monthly sampling was investigated in a salt marsh creek of the Yangtze River estuary. Twenty-one orders of macrozooplankton were captured. Calanoida and Decapoda were dominant and numerically comprised 59.59% and 37.59% respectively of the total captured macrozooplankton throughout the year. Decapoda mainly occurred in April, May and June. In other months, the Calanoida contributed over 90% of the total individuals. The annual Ferrari index (I) for total individual number of macrozooplankton was 0.27, which generally supports the viewpoint that salt marshes are sources of zooplankton. The salt marsh was mainly a source for decapods and mysids, possibly because of larval release in their breeding seasons. The marsh was also a source for amphipods, probably because some benthic forms became transient planktonic forms during tidal water flushing. Copepods and fish larvae exhibited net import into the salt marsh, which may result from predation from salt marsh settlers or retention in the salt marsh. Monthly Ferrari index (I) estimations revealed that the role of the salt marsh as a sink or source of macrozooplankton was time-dependent, which is related to the life history of animals. This study showed that whether the salt marsh zooplankton act as energy importers or exporters is group/taxa-dependent and time-dependent.

  4. Origins of mineral matter in peat marsh and peat bog deposits, Spain

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Buendia, A.M. [Unidad Tecnica del Marmol, AIDICO, Cami de Castella, 4, 03660 Novelda, Alicante (Spain); Whateley, M.K.G. [Rio Tinto Technical Services, Castlemead, Lower Castlemead, BS99 7YR Bristol (United Kingdom); Bastida, J.; Urquiola, M.M. [Dpto. Geologia, Univ. Valencia, Dr. Moliner 50. 46100 Burjasot, Valencia (Spain)

    2007-07-02

    The mineralogy of three back-barrier peat marshes (Torreblanca, Benicasim and Moncofar marshes) from Eastern Spain and one peat bog (Orihuela del Tremedal bog) from central east Spain have been investigated, using X-ray diffraction (XRD) and scanning electronic microscope (SEM) techniques. A combination of XRD methods was used to quantify the mineralogy of dried bulk peat samples. The water source in the peat marshes is both continental and marine. Water is highly mineralised. Water flow is both low and slow (accumulative system). The water source in the peat bog is continental, draining from the hill. The higher concentration of ions in the water of the back-barrier peat marshes leads to a higher concentration of authigenic minerals in the peat marshes compared to the peat bog. Three main mineral origins have been recognized, namely: detrital, syngenetic-epigenetic and biogenic. The more important contribution comes from the detrital system. Biogenic and bio-influenced minerals are the main non-detrital minerals in the peatlands. This paper discusses the biogenic origin of halite (and other minor halides and sulphates, such as, sylvite, carnalite, epsomite, glauberite, mirabilite and anhydrite?) from halophytic plants, as well as amorphous silica (opal-A) from sponge spicules and phytoliths of several plants. Pyrite in the peat bog has both syngenetic and epigenetic origins from plant decomposition and sulphur release. In the peat marsh the pyrite has a syngenetic origin from sulphate reduction (S{sub sulphate} {yields} S{sub pyritic}), and an epigenetic origin in the older peat, from plant decomposition (S{sub organic} {yields} S{sub pyritic}). (author)

  5. Gulf-Wide Information System, Environmental Sensitivity Index Brackish Marsh, Geographic NAD83, LDWF (2001) [esi_brackish_marsh_LDWF_2001

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains Environmental Sensitivity Index (ESI) brackish marshes data of coastal Louisiana. The ESI is a classification and ranking system, which...

  6. Gulf-Wide Information System, Environmental Sensitivity Index Intermediate Marsh, Geographic NAD83, LDWF (2001) [esi_intermediate_marsh_LDWF_2001

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains Environmental Sensitivity Index (ESI) intermediate marshes data of coastal Louisiana. The ESI is a classification and ranking system, which...

  7. Sources and distribution of sedimentary organic matter along the Andong salt marsh, Hangzhou Bay

    Science.gov (United States)

    Yuan, Hong-Wei; Chen, Jian-Fang; Ye, Ying; Lou, Zhang-Hua; Jin, Ai-Min; Chen, Xue-Gang; Jiang, Zong-Pei; Lin, Yu-Shih; Chen, Chen-Tung Arthur; Loh, Pei Sun

    2017-10-01

    Lignin oxidation products, δ13C values, C/N ratios and particle size were used to investigate the sources, distribution and chemical stability of sedimentary organic matter (OM) along the Andong salt marsh located in the southwestern end of Hangzhou Bay, China. Terrestrial OM was highest at the upper marshes and decreased closer to the sea, and the distribution of sedimentary total organic carbon (TOC) was influenced mostly by particle size. Terrestrial OM with a C3 signature was the predominant source of sedimentary OM in the Spartina alterniflora-dominated salt marsh system. This means that aside from contributions from the local marsh plants, the Andong salt marsh received input mostly from the Qiantang River and the Changjiang Estuary. Transect C, which was situated nearer to the Qiantang River mouth, was most likely influenced by input from the Qiantang River. Likewise, a nearby creek could be transporting materials from Hangzhou Bay into Transect A (farther east than Transect C), as Transect A showed a signal resembling that of the Changjiang Estuary. The predominance of terrestrial OM in the Andong salt marsh despite overall reductions in sedimentary and terrestrial OM input from the rivers is most likely due to increased contributions of sedimentary and terrestrial OM from erosion. This study shows that lower salt marsh accretion due to the presence of reservoirs upstream may be counterbalanced by increased erosion from the surrounding coastal areas.

  8. Impact of Coastal Development and Marsh Width Variability on Groundwater Quality in Estuarine Tidal Creeks

    Science.gov (United States)

    Shanahan, M.; Wilson, A. M.; Smith, E. M.

    2017-12-01

    Coastal upland development has been shown to negatively impact surface water quality in tidal creeks in the southeastern US, but less is known about its impact on groundwater. We sampled groundwater in the upland and along the marsh perimeter of tidal creeks located within developed and undeveloped watersheds. Samples were analyzed for salinity, dissolved organic carbon, nitrogen and phosphorus concentrations. Groundwater samples collected from the upland in developed and undeveloped watersheds were compared to study the impact of development on groundwater entering the marsh. Groundwater samples collected along the marsh perimeter were analyzed to study the impact of marsh width variability on groundwater quality within each creek. Preliminary results suggest a positive correlation between salinity and marsh width in undeveloped watersheds, and a higher concentration of nutrients in developed versus undeveloped watersheds.

  9. Tidal Marsh Outwelling of Dissolved Organic Matter and Resulting Temporal Variability in Coastal Water Optical and Biogeochemical Properties

    Science.gov (United States)

    Tzortziou, Maria; Neale, Patrick J.; Megonigal, J. Patrick; Butterworth, Megan; Jaffe, Rudolf; Yamashita, Youhei

    2010-01-01

    Coastal wetlands are highly dynamic environments at the land-ocean interface where human activities, short-term physical forcings and intense episodic events result in high biological and chemical variability. Long being recognized as among the most productive ecosystems in the world, tidally-influenced coastal marshes are hot spots of biogeochemical transformation and exchange. High temporal resolution observations that we performed in several marsh-estuarine systems of the Chesapeake Bay revealed significant variability in water optical and biogeochemical characteristics at hourly time scales, associated with tidally-driven hydrology. Water in the tidal creek draining each marsh was sampled every hour during several semi-diurnal tidal cycles using ISCO automated samplers. Measurements showed that water leaving the marsh during ebbing tide was consistently enriched in dissolved organic carbon (DOC), frequently by more than a factor of two, compared to water entering the marsh during flooding tide. Estimates of DOC fluxes showed a net DOC export from the marsh to the estuary during seasons of both low and high biomass of marsh vegetation. Chlorophyll amounts were typically lower in the water draining the marsh, compared to that entering the marsh during flooding tide, suggesting that marshes act as transformers of particulate to dissolved organic matter. Moreover, detailed optical and compositional analyses demonstrated that marshes are important sources of optically and chemically distinctive, relatively complex, high molecular weight, aromatic-rich and highly colored dissolved organic compounds. Compared to adjacent estuarine waters, marsh-exported colored dissolved organic matter (CDOM) was characterized by considerably stronger absorption (more than a factor of three in some cases), larger DOC-specific absorption, lower exponential spectral slope, larger fluorescence signal, lower fluorescence per unit absorbance, and higher fluorescence at visible wavelengths

  10. Coastal Marsh Longevity, Ecological Succession, and Organic Carbon Dynamics During Early Holocene Sea-Level Rise

    Science.gov (United States)

    Vetter, L.; Schreiner, K. M.; Rosenheim, B. E.; Tornqvist, T. E.

    2016-02-01

    Coastal marsh environments perform essential ecosystem services, including nutrient filtering, soil organic matter storage, and storm surge abatement, yet much is still unknown about their formation and fate under periods of sea-level change. During the early Holocene (7-10 ka), rapid sea-level rise in coastal Louisiana was one of the primary controls over marsh development and longevity. Here, we investigate plant community composition and succession and soil organic matter storage in early Holocene coastal marshes in Louisiana using bulk elemental ratios, lignin phenol biomarkers and stable isotopes from peat layers. Sediment cores were collected in southeastern Louisiana and contain a record of an early Holocene transgressive sea-level sequence 16-25 m below present sea-level. The sedimentary record consists of an immature paleosol overlain by basal peat that accumulated in an estuarine marsh, overlain by marine lagoonal muds. A re-established marsh peat is present 1-4 m above the initial transition to marine conditions, indicating a sequence of marsh development, sea-level rise and onset of marine conditions, and then further marsh development as the rate of relative sea-level rise decelerated. Plant community composition in coastal marshes was determined through cupric oxide oxidation and lignin-phenol and non-lignin-phenol biomarker abundances. The degradation state of soil organic matter and the specific source of stabilized organic matter within the sedimentary peats were determined through lignin-phenol biomarker ratios. Organic matter sources ranged from terrestrial to marine over the course of sea-level rise, and different sites showed different amounts of marine organic matter influence and different levels of terrestrial organic matter degradation. These results have important implications for reconstructing the response of coastal marshes and their plant communities to accelerated rates of sea-level rise projected through 2100.

  11. The Effect of Source Suspended Sediment Concentration on the Sediment Dynamics of a Macrotidal Creek and Salt Marsh

    Science.gov (United States)

    Poirier, E.; van Proosdij, D.; Milligan, T. G.

    2017-12-01

    Seasonal variability in the sediment dynamics of a Bay of Fundy tidal creek and salt marsh system was analyzed to better understand the ecomorphodynamics of a high suspended sediment concentration intertidal habitat. Data were collected over 62 tides for velocity, suspended sediment concentration, deposition, and grain size at four stations from the creek thalweg to the marsh surface. Five topographic surveys were also conducted throughout the 14-month study. Deposition rates per tide varied spatially from 56.4 g·m-2 at the creek thalweg to 15.3 g·m-2 at the marsh surface. Seasonal variations in deposition in the creek and marsh surface were from 38.0 g·m-2 to 97.7 g·m-2 and from 12.2 g·m-2 to 19.6 g·m-2 respectively. Deposition and erosion were greatest in late fall and winter. This seasonal change, led by higher suspended sediment concentrations, was observed in the creek and at the marsh bank but notably absent from the marsh edge and marsh surface. Sediments were predominantly deposited in floc form (76-83%). Because of high floc content, higher suspended sediment concentrations led to more rapid loss of sediment from suspension. With increasing sediment concentration, deposition increased in the tidal creek and at the marsh bank but not at the marsh edge or marsh surface. This suggests that in highly flocculated environments the water column clears fast enough that very little sediment remains in suspension when the water reaches the marsh and that the sediment concentration during marsh inundation is independent of the initial concentration in the creek.

  12. Marsh dieback, loss, and recovery mapped with satellite optical, airborne polarimetric radar, and field data

    Science.gov (United States)

    Ramsey, Elijah W.; Rangoonwala, Amina; Chi, Zhaohui; Jones, Cathleen E.; Bannister, Terri

    2014-01-01

    Landsat Thematic Mapper and Satellite Pour l'Observation de la Terre (SPOT) satellite based optical sensors, NASA Uninhabited Aerial Vehicle synthetic aperture radar (UAVSAR) polarimetric SAR (PolSAR), and field data captured the occurrence and the recovery of an undetected dieback that occurred between the summers of 2010, 2011, and 2012 in the Spartina alterniflora marshes of coastal Louisiana. Field measurements recorded the dramatic biomass decrease from 2010 to 2011 and a biomass recovery in 2012 dominated by a decrease of live biomass, and the loss of marsh as part of the dieback event. Based on an established relationship, the near-infrared/red vegetation index (VI) and site-specific measurements delineated a contiguous expanse of marsh dieback encompassing 6649.9 ha of 18,292.3 ha of S. alterniflora marshes within the study region. PolSAR data were transformed to variables used in biophysical mapping, and of this variable suite, the cross-polarization HV (horizontal send and vertical receive) backscatter was the best single indicator of marsh dieback and recovery. HV backscatter exhibited substantial and significant changes over the dieback and recovery period, tracked measured biomass changes, and significantly correlated with the live/dead biomass ratio. Within the context of regional trends, both HV and VI indicators started higher in pre-dieback marshes and exhibited substantially and statistically higher variability from year to year than that exhibited in the non-dieback marshes. That distinct difference allowed the capturing of the S. alterniflora marsh dieback and recovery; however, these changes were incorporated in a regional trend exhibiting similar but more subtle biomass composition changes.

  13. Indirect human impacts reverse centuries of carbon sequestration and salt marsh accretion.

    Science.gov (United States)

    Coverdale, Tyler C; Brisson, Caitlin P; Young, Eric W; Yin, Stephanie F; Donnelly, Jeffrey P; Bertness, Mark D

    2014-01-01

    Direct and indirect human impacts on coastal ecosystems have increased over the last several centuries, leading to unprecedented degradation of coastal habitats and loss of ecological services. Here we document a two-century temporal disparity between salt marsh accretion and subsequent loss to indirect human impacts. Field surveys, manipulative experiments and GIS analyses reveal that crab burrowing weakens the marsh peat base and facilitates further burrowing, leading to bank calving, disruption of marsh accretion, and a loss of over two centuries of sequestered carbon from the marsh edge in only three decades. Analogous temporal disparities exist in other systems and are a largely unrecognized obstacle in attaining sustainable ecosystem services in an increasingly human impacted world. In light of the growing threat of indirect impacts worldwide and despite uncertainties in the fate of lost carbon, we suggest that estimates of carbon emissions based only on direct human impacts may significantly underestimate total anthropogenic carbon emissions.

  14. Effects of oil on the rate and trajectory of Louisiana marsh shoreline erosion

    International Nuclear Information System (INIS)

    McClenachan, Giovanna; Eugene Turner, R; Tweel, Andrew W

    2013-01-01

    Oil can have long-term detrimental effects on marsh plant health, both above- and belowground. However, there are few data available that quantify the accelerated rate of erosion that oil may cause to marshes and the trajectory of change. Between November 2010 and August 2012, we collected data on shoreline erosion, soil strength, per cent cover of Spartina alterniflora, and marsh edge overhang at 30 closely spaced low oil and high oil sites in Bay Batiste, Louisiana. Surface oil samples were taken one meter into the marsh in February 2011. All high oiled sites in Bay Batiste were contaminated with Macondo 252 oil (oil from the Deepwater Horizon oil spill, 20 April–15 July 2010). The results suggest that there is a threshold where soil parameters change dramatically with a relatively small increase in oil concentration in the soil. Heavy oiling weakens the soil, creating a deeper undercut of the upper 50 cm of the marsh edge, and causing an accelerated rate of erosion that cascades along the shoreline. Our results demonstrate that it could take at least 2 yr to document the effects heavy oiling has had on the marsh shoreline. The presence of aboveground vegetation alone may not be an appropriate indicator of recovery. (letter)

  15. Precision Monitoring of Water Level in a Salt Marsh with Low Cost Tilt Loggers

    Science.gov (United States)

    Sheremet, Vitalii A.; Mora, Jordan W.

    2016-04-01

    Several salt pannes and pools in the Sage Lot tidal marsh of Waquoit Bay system, MA were instrumented with newly developed Arm-and-Float water level gauges (utilizing accelerometer tilt logger) permitting to record water level fluctuations with accuracy of 1 mm and submillimeter resolution. The methodology of the instrument calibration, deployment, and elevation control are described. The instrument performance was evaluated. Several month long deployments allowed us to analyze the marsh flooding and draining processes, study differences among the salt pannes. The open channel flow flooding-draining mechanism and slower seepage were distinguished. From the drain curve the seepage rate can be quantified. The seepage rate remains approximately constant for all flooding draining episodes, but varies from panne to panne depending on bottom type and location. Seasonal differences due to the growth of vegetation are also recorded. The analysis of rain events allows us to estimate the catch area of subbasins in the marsh. The implication for marsh ecology and marsh accretion are discussed. The gradual sea level rise coupled with monthly tidal datum variability and storm surges result in migration and development of a salt marsh. The newly developed low cost instrumentation allows us to record and analyze these changes and may provide guidance for the ecological management.

  16. Guide to Common Tidal Marsh Invertebrates of the Northeastern Gulf of Mexico.

    Science.gov (United States)

    Heard, Richard W.

    The major groups of marine and estuarine macroinvertebrates of the tidal marshes of the northern Gulf of Mexico are described in this guide for students, taxonomists and generalists. Information on the recognition characteristics, distribution, habitat, and biology of salt marsh species from the coelenterate, annelid, mollusk and arthropod phyla…

  17. Silvicultural and logistical considerations associated with the pending reintroduction of American chestnut

    Science.gov (United States)

    Douglass F. Jacobs

    2010-01-01

    Traditional breeding for blight resistance has led to the potential to restore American chestnut (Castanea dentata (Marsh.) Borkh.) to Eastern United States forests using a blight resistant hybrid chestnut tree. With prospects of pending wide-scale reintroduction, restoration strategies based on ecological and biological characteristics of the...

  18. Assessment of static flood modeling techniques: application to contrasting marshes flooded during Xynthia (western France

    Directory of Open Access Journals (Sweden)

    J. F. Breilh

    2013-06-01

    Full Text Available This study aims to assess the performance of raster-based flood modeling methods on a wide diversity of coastal marshes. These methods are applied to the flooding associated with the storm Xynthia, which severely hit the western coast of France in February 2010. Static and semi-dynamic methods are assessed using a combination of LiDAR data, post-storm delineation of flooded areas and sea levels originating from both tide gauge measurements and storm surge modeling. Static methods are applied to 27 marshes showing a wide geomorphological diversity. It appears that these methods are suitable for marshes with a small distance between the coastline and the landward boundary of the marsh, which causes these marshes to flood rapidly. On the contrary, these methods overpredict flooded areas for large marshes where the distance between the coastline and the landward boundary of the marsh is large, because the flooding cannot be considered as instantaneous. In this case, semi-dynamic methods based on surge overflowing volume calculations can improve the flooding prediction significantly. This study suggests that static and semi-dynamic flood modeling methods can be attractive and quickly deployed to rapidly produce predictive flood maps of vulnerable areas under certain conditions, particularly for small distances between the coastline and the landward boundary of the low-lying coastal area.

  19. Vegetation cover, tidal amplitude and land area predict short-term marsh vulnerability in Coastal Louisiana

    Science.gov (United States)

    Schoolmaster, Donald; Stagg, Camille L.; Sharp, Leigh Anne; McGinnis, Tommy S.; Wood, Bernard; Piazza, Sarai

    2018-01-01

    The loss of coastal marshes is a topic of great concern, because these habitats provide tangible ecosystem services and are at risk from sea-level rise and human activities. In recent years, significant effort has gone into understanding and modeling the relationships between the biological and physical factors that contribute to marsh stability. Simulation-based process models suggest that marsh stability is the product of a complex feedback between sediment supply, flooding regime and vegetation response, resulting in elevation gains sufficient to match the combination of relative sea-level rise and losses from erosion. However, there have been few direct, empirical tests of these models, because long-term datasets that have captured sufficient numbers of marsh loss events in the context of a rigorous monitoring program are rare. We use a multi-year data set collected by the Coastwide Reference Monitoring System (CRMS) that includes transitions of monitored vegetation plots to open water to build and test a predictive model of near-term marsh vulnerability. We found that despite the conclusions of previous process models, elevation change had no ability to predict the transition of vegetated marsh to open water. However, we found that the processes that drive elevation change were significant predictors of transitions. Specifically, vegetation cover in prior year, land area in the surrounding 1 km2 (an estimate of marsh fragmentation), and the interaction of tidal amplitude and position in tidal frame were all significant factors predicting marsh loss. This suggests that 1) elevation change is likely better a predictor of marsh loss at time scales longer than we consider in this study and 2) the significant predictive factors affect marsh vulnerability through pathways other than elevation change, such as resistance to erosion. In addition, we found that, while sensitivity of marsh vulnerability to the predictive factors varied spatially across coastal Louisiana

  20. Salt marsh construction costs and shrimp production

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Continuing wetland loss in Galveston Bay, Texas (USA) has led to the development of various salt marsh restoration projects. These constructed wetlands often attempt...

  1. Biofilms' contribution to organic carbon in salt marsh sediments

    Science.gov (United States)

    Valentine, K.; Quirk, T. E.; Mariotti, G.; Hotard, A.

    2017-12-01

    Coastal salt marshes are productive environments with high potential for carbon (C) accumulation. Organic C in salt marsh sediment is typically attributed to plant biomass. Recent field measurements, however, suggest that biofilms - mainly composed of benthic diatoms and their secretion - also contribute to basal C in these environments and can be important contributors to marsh productivity, C cycling, and potentially, C sequestration. The potential for biofilms to soil organic C and the influence of mineral sedimentation of biofilm-based C accumulation is unknown. We conducted controlled laboratory experiments to test (1) whether biofilms add measurable amounts of organic C to the sediment and (2) the effect of mineral sedimentation rate on the amount of biofilm-based C accumulation. Settled beds of pure bentonite mud were created in 10-cm-wide cylinders. Each cylinder was inoculated with biofilms collected from a marsh in Louisiana. A small amount of mud was added weekly for 11 weeks. Control experiments without biofilms were also performed. Biofilms were grown with a 12/12 hours cycle, with a gentle mixing of the water column that did not cause sediment resuspension, with a nutrient-rich medium that was exchanged weekly, and in the absence of metazoan grazing. At the end of the experiment, the sediment columns were analyzed for depth-integrated chl-a, loss on ignition (LOI), and total organic carbon (TOC). Chl-a values ranged from 26-113 mg/cm2, LOI values ranged from 86-456 g/m2/yr, and TOC values ranged from 31-211 g/m2/yr. All three of these metrics (chl-a, LOI, and TOC) increased with the rate of mineral sedimentation. These results show that biofilms, in the absence of erosion and grazing, can significantly contribute to C accumulation in salt marshes, especially with high rates of mineral sedimentation. Given the short time scale of the experiment, the increase in organic C accumulation with the rate of sedimentation is attributed to stimulated biofilm

  2. Automated Detection of Salt Marsh Platforms : a Topographic Method

    Science.gov (United States)

    Goodwin, G.; Mudd, S. M.; Clubb, F. J.

    2017-12-01

    Monitoring the topographic evolution of coastal marshes is a crucial step toward improving the management of these valuable landscapes under the pressure of relative sea level rise and anthropogenic modification. However, determining their geometrically complex boundaries currently relies on spectral vegetation detection methods or requires labour-intensive field surveys and digitisation.We propose a novel method to reproducibly isolate saltmarsh scarps and platforms from a DEM. Field observations and numerical models show that saltmarshes mature into sub-horizontal platforms delineated by sub-vertical scarps: based on this premise, we identify scarps as lines of local maxima on a slope*relief raster, then fill landmasses from the scarps upward, thus isolating mature marsh platforms. Non-dimensional search parameters allow batch-processing of data without recalibration. We test our method using lidar-derived DEMs of six saltmarshes in England with varying tidal ranges and geometries, for which topographic platforms were manually isolated from tidal flats. Agreement between manual and automatic segregation exceeds 90% for resolutions of 1m, with all but one sites maintaining this performance for resolutions up to 3.5m. For resolutions of 1m, automatically detected platforms are comparable in surface area and elevation distribution to digitised platforms. We also find that our method allows the accurate detection of local bloc failures 3 times larger than the DEM resolution.Detailed inspection reveals that although tidal creeks were digitised as part of the marsh platform, automatic detection classifies them as part of the tidal flat, causing an increase in false negatives and overall platform perimeter. This suggests our method would benefit from a combination with existing creek detection algorithms. Fallen blocs and pioneer zones are inconsistently identified, particularly in macro-tidal marshes, leading to differences between digitisation and the automated method

  3. Biology and life history of Atanycolus cappaerti (Hymenoptera: Braconidae), a north american larval parasitoid attacking the invasive Emerald Ash Borer (Coleoptera: Buprestidae)

    Science.gov (United States)

    Atanycolus cappaerti Marsh and Strazanac is a native North American parasitoid that has been found to parasitize the emerald ash borer, Agrilus planipennis Fairmaire, a serious invasive pests of North American ash trees (Fraxinus spp.). To facilitate the development of potential augmentative biocon...

  4. Tidal events and salt-marsh structure influence black mangrove (Avicennia germinans) recruitment across an ecotone.

    Science.gov (United States)

    Peterson, Jennifer M; Bell, Susan S

    2012-07-01

    Field experiments were conducted at a black mangrove-salt-marsh ecotone in southwest Florida (U.S.A.) to investigate retention of propagules of the black mangrove, Avicennia germinans, by salt-marsh plants as a mechanism of facilitation operating on recruitment success at landward boundaries. Buoyant A. germinans propagules are dispersed by tides, and stranding is required for establishment; therefore, processes that enable stranding should facilitate mangrove recruitment. We expected the physical structure of salt-marsh vegetation to define propagule retention capacity, and we predicted that salt-marsh plants with distinct growth forms would differentially retain propagules. Experimental monoculture plots (1 m2) of salt-marsh plants with different growth forms (Sporobolus virginicus [grass], Sesuvium portulacastrum [succulent forb], and Batis maritima [succulent scrub]) were created, and A. germinans propagules were emplaced into these plots and monitored over time. For comparison, propagules were also placed into natural polyculture plots (1 m2). Polyculture plots contained at least two of the salt-marsh plant taxa selected for monoculture treatments, and S. virginicus was always present within these polyculture plots. Natural polyculture plots retained 59.3% +/- 11.0% (mean +/- SE) of emplaced propagules. Monocultures varied in their propagule retention capacities with plots of S. virginicus retaining on average 65.7% +/- 11.5% of transplanted propagules compared to 7.2% +/- 1.8% by B. maritima and 5.0% +/- 1.9% by S. portulacastrum. Plots containing S. virginicus retained a significantly greater percentage of emplaced propagules relative to the two succulent salt-marsh taxa. Furthermore, propagule entrapment, across all treatments, was strongly correlated with salt-marsh structure (r2 = 0.6253, P = 0.00001), which was estimated using an indirect quantitative metric (lateral obstruction) calculated from digital images of plots. Overall, our findings imply that

  5. Radionuclides transfer into halophytes growing in tidal salt marshes from the Southwest of Spain

    International Nuclear Information System (INIS)

    Luque, Carlos J.; Vaca, Federico; García-Trapote, Ana; Hierro, Almudena; Bolívar, Juan P.; Castellanos, Eloy M.

    2015-01-01

    Estuaries are sinks of materials and substances which are released directly into them or transported from rivers that drain the basin. It is usual to find high organic matter loads and fine particles in the sediments. We analyzed radionuclide concentrations ("2"1"0Po, "2"3"0Th, "2"3"2Th, "2"3"4U, "2"3"8U, "2"2"6Ra, "2"2"8Th, "2"2"8Ra, "4"0K) in sediments and three different organs (roots, stems and leaves) of three species of halophytes plants (Spartina maritima, Spartina densiflora and Sarcocornia perennis). The study was carried out in two tidal salt marshes, one polluted by U-series radionuclides and another nearby that was unpolluted and was used as a control (or reference) area. The Tinto River salt marsh shows high levels of U-series radionuclides coming from mining and industrial discharges. On the contrary, the unperturbed Piedras River salt marsh is located about 25 km from the Tinto marsh, and shows little presence of contaminants and radionuclides. The results of this work have shown that natural radionuclide concentrations (specially the U-isotopes) in the Tinto salt marsh sediments are one order of magnitude higher than those in the Piedras marsh. These radionuclide enhancements are reflected in the different organs of the plants, which have similar concentration increases as the sediments where they have grown. Finally, the transfer factor (TF) of the most polluted radionuclides (U-isotopes and "2"1"0Po) in the Tinto area are one order of magnitude higher than in the Piedras area, indicating that the fraction of each radionuclide in the sediment originating from the pollution is more available for the plants than the indigenous fraction. This means that the plants of the salt marshes are unhelpful as bioindicators or for the phytoremediation of radionuclides. - Highlights: • Radionuclides were analyzed in sediments and plants in unpolluted salt marshes. • Plants uptake radionuclides in all organs in both salt marshes. • The transfer factors

  6. Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI) design

    OpenAIRE

    Rochlin, Ilia; Iwanejko, Tom; Dempsey, Mary E; Ninivaggi, Dominick V

    2009-01-01

    Abstract Background In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted h...

  7. Delineation of marsh types from Corpus Christi Bay, Texas, to Perdido Bay, Alabama, in 2010

    Science.gov (United States)

    Enwright, Nicholas M.; Hartley, Stephen B.; Couvillion, Brady R.; Michael G. Brasher,; Jenneke M. Visser,; Michael K. Mitchell,; Bart M. Ballard,; Mark W. Parr,; Barry C. Wilson,

    2015-07-23

    Coastal zone managers and researchers often require detailed information regarding emergent marsh vegetation types (that is, fresh, intermediate, brackish, and saline) for modeling habitat capacities and needs of marsh dependent taxa (such as waterfowl and alligator). Detailed information on the extent and distribution of emergent marsh vegetation types throughout the northern Gulf of Mexico coast has been historically unavailable. In response, the U.S. Geological Survey, in collaboration with the Gulf Coast Joint Venture, the University of Louisiana at Lafayette, Ducks Unlimited, Inc., and the Texas A&M University-Kingsville, produced a classification of emergent marsh vegetation types from Corpus Christi Bay, Texas, to Perdido Bay, Alabama.

  8. A trophic cascade triggers collapse of a salt-marsh ecosystem with intensive recreational fishing.

    Science.gov (United States)

    Altieri, Andrew H; Bertness, Mark D; Coverdale, Tyler C; Herrmann, Nicholas C; Angelini, Christine

    2012-06-01

    Overexploitation of predators has been linked to the collapse of a growing number of shallow-water marine ecosystems. However, salt-marsh ecosystems are often viewed and managed as systems controlled by physical processes, despite recent evidence for herbivore-driven die-off of marsh vegetation. Here we use field observations, experiments, and historical records at 14 sites to examine whether the recently reported die-off of northwestern Atlantic salt marshes is associated with the cascading effects of predator dynamics and intensive recreational fishing activity. We found that the localized depletion of top predators at sites accessible to recreational anglers has triggered the proliferation of herbivorous crabs, which in turn results in runaway consumption of marsh vegetation. This suggests that overfishing may be a general mechanism underlying the consumer-driven die-off of salt marshes spreading throughout the western Atlantic. Our findings support the emerging realization that consumers play a dominant role in regulating marine plant communities and can lead to ecosystem collapse when their impacts are amplified by human activities, including recreational fishing.

  9. Interagency partnership to assess and restore a degraded urban riverine wetland: Dyke Marsh Wildlife Preserve, Virginia

    Science.gov (United States)

    Steury, Brent W.; Litwin, Ronald J.; Oberg, Erik T.; Smoot, Joseph P.; Pavich, Milan J.; Sanders, Geoffrey; Santucci, Vincent L.

    2014-01-01

    The narrow-leaved cattail wetland known as Dyke Marsh formally became a land holding of George Washington Memorial Parkway (GWMP, a unit of the national park system) in 1959, along with a congressional directive to honor a newly-let 30-year commercial sand and gravel dredge-mining lease at the site. Dredging continued until 1974 when Public Law 93-251 called for the National Park Service and the United States Army Corps of Engineers to “implement restoration of the historical and ecological values of Dyke Marsh.” By that time, about 83 acres of the marsh remained, and no congressional funding accompanied the passage of the law to effect any immediate conservation or restoration. Decades of dredge mining had severely altered the surface area of Dyke Marsh, the extent of its tidal creek system, and the shallow river bottom of the Potomac River abutting the marsh. Further, mining destabilized the marsh, causing persistent erosion, shoreline retreat, and tidal channel widening after mining ceased. Erosion has continued unchecked until the present; approximately 50 acres of the original marsh are now estimated to remain. The specific cause of persistent erosion had been unknown prior to this collaborative study but previously was assumed to be due to flooding by the Potomac River.

  10. Dynamics of mangrove-marsh ecotones in subtropical coastal wetlands: fire, sea-level rise, and water levels

    Science.gov (United States)

    Smith, Thomas J.; Foster, Ann M.; Tiling-Range, Ginger; Jones, John W.

    2013-01-01

    Ecotones are areas of sharp environmental gradients between two or more homogeneous vegetation types. They are a dynamic aspect of all landscapes and are also responsive to climate change. Shifts in the position of an ecotone across a landscape can be an indication of a changing environment. In the coastal Everglades of Florida, USA, a dominant ecotone type is that of mangrove forest and marsh. However, there is a variety of plants that can form the marsh component, including sawgrass (Cladium mariscus [L.] Pohl), needlegrass rush (Juncus roemerianus Scheele), and spikerush (Eleocharis spp.). Environmental factors including water depth, soil type, and occurrence of fires vary across these ecotones, influencing their dynamics. Altered freshwater inflows from upstream and increasing sea level over the past 100 years may have also had an impact. We analyzed a time series of historical aerial photographs for a number of sites in the coastal Everglades and measured change in position of mangrove–marsh ecotones. For three sites, detailed maps were produced and the area of marsh, mangrove, and other habitats was determined for five periods spanning the years 1928 to 2004. Contrary to our initial hypothesis on fire, we found that fire did not prevent mangrove expansion into marsh areas but may in fact assist mangroves to invade some marsh habitats, especially sawgrass. Disparate patterns in mangrove–marsh change were measured at two downstream sites, both of which had multiple fires over from 1948 to 2004. No change in mangrove or marsh area was measured at one site. Mangrove area increased and marsh area decreased at the second of these fire-impacted sites. We measured a significant increase in mangrove area and a decline in marsh area at an upstream site that had little occurrence of fire. At this site, water levels have increased significantly as sea level has risen, and this has probably been a factor in the mangrove expansion.

  11. Comparison of Bottomless Lift Nets and Breder Traps for Sampling Salt-Marsh Nekton

    Science.gov (United States)

    Vegetated salt-marsh surfaces provide refuge, forage, and spawning habitat for estuarine nekton, yet are threatened by accelerating rates of sea-level rise in southern New England and elsewhere. Nekton responses to ongoing marsh surface changes need to be evaluated with effective...

  12. Maintenance of salt barrens inhibited landward invasion of Spartina species in salt marshes

    NARCIS (Netherlands)

    Qi, Man; Sun, Tao; Zhang, Heyue; Zhu, Meisha; Yang, Ying-Wei; Shao, Dongdong; Voinov, Alexey

    2017-01-01

    Spartina spp. (cordgrasses) often dominates intertidal mudflats and/or low marshes. The landward invasion of these species was typically thought to be restrained by low tidal inundation frequencies and interspecific competition. We noticed that the reported soil salinity levels in some salt marshes

  13. Final report for sea-level rise response modeling for San Francisco Bay estuary tidal marshes

    Science.gov (United States)

    Takekawa, John Y.; Thorne, Karen M.; Buffington, Kevin J.; Spragens, Kyle A.; Swanson, Kathleen M.; Drexler, Judith Z.; Schoellhamer, David H.; Overton, Cory T.; Casazza, Michael L.

    2013-01-01

    The International Panel on Climate Change has identified coastal ecosystems as areas that will be disproportionally affected by climate change. Current sea-level rise projections range widely with 0.57 to 1.9 meters increase in mea sea level by 2100. The expected accelerated rate of sea-level rise through the 21st century will put many coastal ecosystems at risk, especially those in topographically low-gradient areas. We assessed marsh accretion and plant community state changes through 2100 at 12 tidal salt marshes around San Francisco Bay estuary with a sea-level rise response model. Detailed ground elevation, vegetation, and water level data were collected at all sites between 2008 and 2011 and used as model inputs. Sediment cores (taken by Callaway and others, 2012) at four sites around San Francisco Bay estuary were used to estimate accretion rates. A modification of the Callaway and others (1996) model, the Wetland Accretion Rate Model for Ecosystem Resilience (WARMER), was utilized to run sea-level rise response models for all sites. With a mean sea level rise of 1.24 m by 2100, WARMER projected that the vast majority, 95.8 percent (1,942 hectares), of marsh area in our study will lose marsh plant communities by 2100 and to transition to a relative elevation range consistent with mudflat habitat. Three marshes were projected to maintain marsh vegetation to 2100, but they only composed 4.2 percent (85 hectares) of the total marsh area surveyed.

  14. Tidal marsh plant responses to elevated CO2 , nitrogen fertilization, and sea level rise.

    Science.gov (United States)

    Adam Langley, J; Mozdzer, Thomas J; Shepard, Katherine A; Hagerty, Shannon B; Patrick Megonigal, J

    2013-05-01

    Elevated CO2 and nitrogen (N) addition directly affect plant productivity and the mechanisms that allow tidal marshes to maintain a constant elevation relative to sea level, but it remains unknown how these global change drivers modify marsh plant response to sea level rise. Here we manipulated factorial combinations of CO2 concentration (two levels), N availability (two levels) and relative sea level (six levels) using in situ mesocosms containing a tidal marsh community composed of a sedge, Schoenoplectus americanus, and a grass, Spartina patens. Our objective is to determine, if elevated CO2 and N alter the growth and persistence of these plants in coastal ecosystems facing rising sea levels. After two growing seasons, we found that N addition enhanced plant growth particularly at sea levels where plants were most stressed by flooding (114% stimulation in the + 10 cm treatment), and N effects were generally larger in combination with elevated CO2 (288% stimulation). N fertilization shifted the optimal productivity of S. patens to a higher sea level, but did not confer S. patens an enhanced ability to tolerate sea level rise. S. americanus responded strongly to N only in the higher sea level treatments that excluded S. patens. Interestingly, addition of N, which has been suggested to accelerate marsh loss, may afford some marsh plants, such as the widespread sedge, S. americanus, the enhanced ability to tolerate inundation. However, if chronic N pollution reduces the availability of propagules of S. americanus or other flood-tolerant species on the landscape scale, this shift in species dominance could render tidal marshes more susceptible to marsh collapse. © 2013 Blackwell Publishing Ltd.

  15. How is the chlorophyll count affected by burned and unburned marsh areas?

    Science.gov (United States)

    Kendrick, C.

    2017-12-01

    Does marsh burnings, either man made or natural, hinder or help Louisiana's vitally important coastal plant life? Does the carbon produced from the fires have a negative effect on the chlorophyll count of these precious living protective barriers? Or does it help contribute to raising the plants chlorophyll count? Along Louisiana's Gulf Coast, marsh burnings are conducted every 2-4 years to destroy some of the Spartina patens. Fires and smoke may have an effect on the chlorophyll count of the plants found in Louisiana's marshes. Peat burns, root burns, and cover burns are the three types of marsh fires. These burns can be either man made or started by natural causes. Peat burns occur when the soil is dry due to a drained marsh. Root burns occur when plant roots are burned without the soil being consumed. Cover burns occur when several centimeters of water covers the soil. Cover burns are often used by Wildlife and Fisheries personnel to promote preferred plant food growth like Scirpus olneyi rather than the dominant Spartina patens. Our project was conducted by testing marsh plants and obtaining chlorophyll count of both a burned (cover burn) and an unburned area. Approximately one year after the burn, in August 2015, we tested the burned area's site. We retested the same site in December 2016. The results from our testing showed that there was a slightly higher chlorophyll count in the burned area. The chlorophyll count average from the two testing days was 33.5 in the burned area and 30.15 in the unburned area. Our hypothesis was that the chlorophyll content of "controlled" burned wetland areas will have a higher amount than the "no" burn area. The experiment results supported this hypothesis by showing an increase of 3.35 average in the burned area.

  16. Tritium behaviour in aquatic plants and animals in a freshwater marsh ecosystem

    International Nuclear Information System (INIS)

    Adams, L.W.; Peterle, T.J.; White, G.C.

    1979-01-01

    Ten curies of tritium as tritiated water (HTO) were experimentally added to an enclosed 2-ha Lake Erie marsh on 20 October 1973. Tritium kinetics in selected plants and animals were determined over a one-year period. Tritium levels in the marsh bottom sediment averaged 1.8 times the marsh water levels, with little evidence of tritium concentration above the marsh water tritium levels in the flora and fauna. The unbound tritium: marsh water tritium ratios in smartweed (Polygonum lapathifolium) and pickerelweed (Pontederia cordata) (both emergents) were lower than the same ratio for pondweed (Potamogeton crispus) (a submergent). There was some evidence of bound tritium buildup in midsummer, particularly in the pondweed. Tritium uptake into the unbound compartments of crayfish (Procambarus blandingi), carp (Cyprinus carpio) and bluegills (Lepomis macrochirus) was rapid. For crayfish, maximum HTO levels were observed on days 2 and 3 following treatment for muscle and viscera respectively. Unbound HTO in carp muscle peaked in 4 hours and the level in carp viscera reached a maximum in 2 days, in bluegill muscle and viscera on day 1. Unbound HTO in all species decreased following peak levels, paralleling marsh water HTO activity. Tritium uptake into the bound compartments was not as rapid nor were the levels as high as for unbound HTO in the fauna. The peak bound level in crayfish muscle was observed on day 10 (bound : unbound ratio of 0.34) and the maximum level in viscera was noted on day 20 (bound : unbound ratio of 0.23). Bound tritium in carp muscle and viscera reached maximum levels on day 20 (bound : unbound ratios of 0.25 and 0.39 respectively). In bluegills, peaks were reached on days 5 and 7 (bound : unbound ratios of 0.35 and 0.38 for muscle and viscera respectively). Bound tritium in all species decreased following maximum levels

  17. Post-mortem ecosystem engineering by oysters creates habitat for a rare marsh plant.

    Science.gov (United States)

    Guo, Hongyu; Pennings, Steven C

    2012-11-01

    Oysters are ecosystem engineers in marine ecosystems, but the functions of oyster shell deposits in intertidal salt marshes are not well understood. The annual plant Suaeda linearis is associated with oyster shell deposits in Georgia salt marshes. We hypothesized that oyster shell deposits promoted the distribution of Suaeda linearis by engineering soil conditions unfavorable to dominant salt marsh plants of the region (the shrub Borrichia frutescens, the rush Juncus roemerianus, and the grass Spartina alterniflora). We tested this hypothesis using common garden pot experiments and field transplant experiments. Suaeda linearis thrived in Borrichia frutescens stands in the absence of neighbors, but was suppressed by Borrichia frutescens in the with-neighbor treatment, suggesting that Suaeda linearis was excluded from Borrichia frutescens stands by interspecific competition. Suaeda linearis plants all died in Juncus roemerianus and Spartina alterniflora stands, regardless of neighbor treatments, indicating that Suaeda linearis is excluded from these habitats by physical stress (likely water-logging). In contrast, Borrichia frutescens, Juncus roemerianus, and Spartina alterniflora all performed poorly in Suaeda linearis stands regardless of neighbor treatments, probably due to physical stresses such as low soil water content and low organic matter content. Thus, oyster shell deposits play an important ecosystem engineering role in influencing salt marsh plant communities by providing a unique niche for Suaeda linearis, which otherwise would be rare or absent in salt marshes in the southeastern US. Since the success of Suaeda linearis is linked to the success of oysters, efforts to protect and restore oyster reefs may also benefit salt marsh plant communities.

  18. The sedimentological characteristics and geochronology of the marshes of Dauphin Island, Alabama

    Science.gov (United States)

    Ellis, Alisha M.; Smith, Christopher G.; Marot, Marci E.

    2018-03-22

    In August 2015, scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center collected 11 push cores from the marshes of Dauphin Island and Little Dauphin Island, Alabama. Sample site environments included high marshes, low salt marshes, and salt flats, and varied in distance from the shoreline. The sampling efforts were part of a larger study to assess the feasibility and sustainability of proposed restoration efforts for Dauphin Island, Alabama, and to identify trends in shoreline erosion and accretion. The data presented in this publication can provide a basis for assessing organic and inorganic sediment accumulation rates and temporal changes in accumulation rates over multiple decades at multiple locations across the island. This study was funded by the National Fish and Wildlife Foundation, via the Gulf Environmental Benefit Fund. This report serves as an archive for the sedimentological and geochemical data derived from the marsh cores. Downloadable data are available and include Microsoft Excel spreadsheets (.xlsx), comma-separated values (.csv) text files, JPEG files, and formal Federal Geographic Data Committee metadata in a U.S. Geological Survey data release.

  19. PEAT ACCRETION HISTORIES DURING THE PAST 6000 YEARS IN MARSHES OF THE SACRAMENTO - SAN JOAQUIN DELTA, CALIFORNIA, USA

    Energy Technology Data Exchange (ETDEWEB)

    Drexler, J Z; de Fontaine, C S; Brown, T A

    2009-07-20

    Peat cores were collected in 4 remnant marsh islands and 4 drained, farmed islands throughout the Sacramento - San Joaquin Delta of California in order to characterize the peat accretion history of this region. Radiocarbon age determination of marsh macrofossils at both marsh and farmed islands showed that marshes in the central and western Delta started forming between 6030 and 6790 cal yr BP. Age-depth models for three marshes were constructed using cubic smooth spline regression models. The resulting spline fit models were used to estimate peat accretion histories for the marshes. Estimated accretion rates range from 0.03 to 0.49 cm yr{sup -1} for the marsh sites. The highest accretion rates are at Browns Island, a marsh at the confluence of the Sacramento and San Joaquin rivers. Porosity was examined in the peat core from Franks Wetland, one of the remnant marsh sites. Porosity was greater than 90% and changed little with depth indicating that autocompaction was not an important process in the peat column. The mean contribution of organic matter to soil volume at the marsh sites ranges from 6.15 to 9.25% with little variability. In contrast, the mean contribution of inorganic matter to soil volume ranges from 1.40 to 8.45% with much greater variability, especially in sites situated in main channels. These results suggest that marshes in the Delta can be viewed as largely autochthonous vs. allochthonous in character. Autochthonous sites are largely removed from watershed processes, such as sediment deposition and scour, and are dominated by organic production. Allochthonous sites have greater fluctuations in accretion rates due to the variability of inorganic inputs from the watershed. A comparison of estimated vertical accretion rates with 20th century rates of global sea-level rise shows that currently marshes are maintaining their positions in the tidal frame, yet this offers little assurance of sustainability under scenarios of increased sea-level rise in

  20. Changing Sediment Dynamics of a Mature Backbarrier Salt Marsh in Response to Sea-Level Rise and Storm Events

    Directory of Open Access Journals (Sweden)

    Mark Schuerch

    2018-05-01

    Full Text Available Our study analyses the long-term development of a tidal backbarrier salt marsh in the northern German Wadden Sea. The focus lies on the development of the high-lying, inner, mature part of the salt marsh, which shows a striking history of changing sediment dynamics. The analysis of high-resolution old aerial photographs and sampled sediment cores suggests that the mature part of the marsh was shielded by a sand barrier from the open sea for decades. The supply with fine-grained sediments occurred from the marsh inlet through the tidal channels to the inner salt marsh. Radiometric dating (210Pb and 137Cs reveals that the sedimentation pattern changed fundamentally around the early-mid 1980s when the sedimentation rates increased sharply. By analyzing the photographic evidence, we found that the sand barrier was breached during storm events in the early 1980s. As a result, coarse-grained sediments were brought directly through this overwash from the sea to the mature part of the salt marsh and increased the sedimentation rates. We show that the overwash and the channels created by these storm events built a direct connection to the sea and reduced the distance to the sediment source which promoted salt marsh growth and a supply with coarse-grained sediments. Consequently, the original sediment input from the tidal channels is found to play a minor role in the years following the breach event. The presented study showcases the morphological development of a mature marsh, which contradicts the commonly accepted paradigm of decreasing sedimentation rates with increasing age of the marsh. We argue that similar trends are likely to be observed in other backbarrier marshes, developing in the shelter of unstabilized sand barriers. It further highlights the question of how resilient these salt marshes are toward sea level rise and how extreme storm events interfere in determining the resilience of a mature salt marsh.

  1. Annual net ecosystem exchanges of carbon dioxide and methane from a temperate brackish marsh: should the focus of marsh restoration be on brackish environments?

    Science.gov (United States)

    Windham-Myers, L.; Anderson, F. E.; Bergamaschi, B. A.; Ferner, M. C.; Schile, L. M.; Spinelli, G.

    2015-12-01

    The exchange and transport of carbon in tidally driven, saline marsh ecosystems provide habitat and trophic support for coastal wildlife and fisheries, while potentially accumulating and storing carbon at some of the highest rates compared to other ecosystems. However, due to the predicted rise in sea level over the next century, the preservation and restoration of estuarine habitats is necessary to compensate for their expected decline. In addition, restoration of these marsh systems can also reduce the impacts of global climate change as they assimilate as much carbon as their freshwater counterparts, while emitting less methane due to the higher concentrations of sulfate in seawater. Unfortunately, in brackish marshes, with salinity concentrations less than 18 parts per thousand (ppt), simple relationships between methane production, salinity and sulfate concentrations are not well known. Here we present the net ecosystem exchange (NEE) of carbon dioxide and methane, as calculated by the eddy covariance method, from a brackish marsh ecosystem in the San Francisco Estuary where salinity ranges from oligohaline (0.5-5 ppt) to mesohaline (5-18 ppt) conditions. Daily rates of carbon dioxide and methane NEE ranged from approximately 10 gC-CO2 m-2 d-1 and 0 mgC-CH4 m-2 d-1, during the winter to -15 gC-CO2 m-2 d-1 and 30 mgC-CH4 m-2 d-1, in the summer growing season. A comparison between similar measurements made from freshwater wetlands in the Sacramento-San Joaquin Delta found that the daily rates of carbon dioxide NEE were similar, but daily rates of methane NEE were just a small fraction (0-15%). Our research also shows that the daily fluxes of carbon dioxide and methane at the brackish marsh were highly variable and may be influenced by the tidal exchanges of seawater. Furthermore, the observed decline in methane production from summer to fall may have resulted from a rise in salinity and/or a seasonal decline in water and air temperatures. Our research goals are

  2. Traits of estuarine marsh plants affect wave dissipation

    Science.gov (United States)

    Schulte Ostermann, Tilla; Heuner, Maike; Bouma, Tjeerd

    2017-04-01

    Estuarine vegetation can attenuate hydrodynamic forces such as waves or flow velocities and therefore has an important role in natural tidal bank protection. This function depends on the degree of hydrodynamic forces, bank morphology and on plant traits of the dominant species. The traits vary between the species but also between different marsh sites. Biomass, stem density and biomechanical properties are crucial factors that influence the rate of wave dissipation. These properties illustrate the trade-offs a species is facing in such a dynamic habitat and highlight the ability of dominant species such as Bolboschoenus maritimus and Schoenoplectus tabernaemontani to protect the tidal bank. Along the Elbe estuary, traits of dominant marsh plant species were measured on different sites. The sites vary e.g. in their elevation, salt levels and inundation periods. To analyse the role that plant traits can play in wave dissipation, the structure of the vegetation as well as the composition was recorded. Biomechanical tests helped to understand the species traits regarding stem flexibility and to determine the effects of plant traits on wave dynamics and vice versa. On the conference, we will present how plant traits affect the wave dissipation on tidal marshes and why they vary.

  3. Methane fluxes along a salinity gradient on a restored salt marsh, Harpswell, ME

    Science.gov (United States)

    Gunn, Cailene; Johnson, Beverly, ,, Dr.; Dostie, Phil; Bohlen, Curtis; Craig, Matthew

    2016-04-01

    This study functions as a pilot project to understand the relationship between salinity and methane emissions on a recently restored salt marsh in Casco Bay, Maine. Salt marshes are dynamic and highly productive ecosystems that provide a multitude of ecosystem services including nutrient filtration, storm-water buffering and carbon sequestration. These ecosystems are highly susceptible to anthropogenic alteration. The emplacement of causeways and narrow culverts, restricts tidal flow and leads to loss of healthy salinity gradients. Consequently, numerous salt marshes have experienced increases in freshwater vegetation growth as a result of coastal population expansion. Recent restoration efforts on Long Marsh, Harpswell, ME replaced a severely undersized culvert with a larger one in February, 2014. The salinity gradient has since been restored along much of the marsh, and freshwater vegetation that encroached on the marsh platform has died back. Vegetation and salinity are key indicators and drivers of CH4 emissions on salt marshes. Using static gas chambers, we quantified CH4 fluxes along two transects at five diverse sites ranging from healthy marsh (salinity of 27 to 31 psu) with Spartina vegetation, to regions invaded by Typha and other freshwater vegetation (salinity of 0 to 4 psu). Sampling was executed in the months of July, August and October. CH4 concentrations were determined using a gas chromatograph with a flame-ionization detector. Preliminary findings suggest reintroduction of healthy tidal flows into the marsh inhibits CH4 production, where the lowest fluxes with least variability were observed at the most saline sites with Spartina vegetation. The largest range of CH4 fluxes exhibited emissions from 0.75 μmol CH4/m2/hr to 518.4 μmol CH4/m2/hr at the Typha dominated sites from July to October. Fluxes at the saltwater and brackish regions were far less variable with ranges from 0.94 μmol CH4/m2/hr to 8.2 μmol CH4/m2/hr and 2.6 to 9.5 μmol CH4/m2

  4. Salt marsh stability modelled in relation to sea level rise

    DEFF Research Database (Denmark)

    Bartholdy, Jesper; Bartholdy, Anders; Kroon, Aart

    2010-01-01

    thickness. Autocompaction was incorporated in the model, and shown to play a major role for the translation of accretion rates measured as length per unit time to accumulation rates measured as mass per area per unit time. This is important, even for shallow salt marsh deposits for which it is demonstrated...... that mass depth down core can be directly related to the bulk dry density of the surface layer by means of a logarithmic function. The results allow for an evaluation of the use of marker horizons in the topmost layers and show that it is important to know the level of the marker in relation to the salt...... marsh base. In general, deeper located markers will indicate successively smaller accretion rates with the same sediment input. Thus, stability analysis made on the basis of newly established marker horizons will be biased and indicate salt marsh stabilities far above the correct level. Running...

  5. Common Marsh Plants of the United States and Canada. Resource Publication 93.

    Science.gov (United States)

    Hotchkiss, Neil

    Described in this guide are the emergent and semiemergent plants most likely to be found in inland and coastal marshes. The guide is intended for field identification of marsh plants without resources to technical botanical keys. The plants are discussed in seven groups. Within each group the kinds which resemble one another most closely are next…

  6. Methane emission from tidal freshwater marshes

    NARCIS (Netherlands)

    Van der Nat, F.J.; Middelburg, J.J.

    2000-01-01

    In two tidal freshwater marshes, methane emission, production and accumulation in the pore-water have been studied. The two sites differ in their dominant vegetation, i.e., reed and bulrush, and in their heights above sea level. The reed site was elevated in relation to the bulrush site and had

  7. A forward-looking, national-scale remote sensing-based model of tidal marsh aboveground carbon stocks

    Science.gov (United States)

    Holmquist, J. R.; Byrd, K. B.; Ballanti, L.; Nguyen, D.; Simard, M.; Windham-Myers, L.; Thomas, N.

    2017-12-01

    Remote sensing based maps of tidal marshes, both of their extents and carbon stocks, have the potential to play a key role in conducting greenhouse gas inventories and implementing climate mitigation policies. Our goal was to generate a single remote sensing model of tidal marsh aboveground biomass and carbon that represents nationally diverse tidal marshes within the conterminous United States (CONUS). To meet this objective we developed the first national-scale dataset of aboveground tidal marsh biomass, species composition, and aboveground plant carbon content (%C) from six CONUS regions: Cape Cod, MA, Chesapeake Bay, MD, Everglades, FL, Mississippi Delta, LA, San Francisco Bay, CA, and Puget Sound, WA. Using the random forest algorithm we tested Sentinel-1 radar backscatter metrics and Landsat vegetation indices as predictors of biomass. The final model, driven by six Landsat vegetation indices and with the soil adjusted vegetation index as the most important (n=409, RMSE=310 g/m2, 10.3% normalized RMSE), successfully predicted biomass and carbon for a range of marsh plant functional types defined by height, leaf angle and growth form. Model error was reduced by scaling field measured biomass by Landsat fraction green vegetation derived from object-based classification of National Agriculture Imagery Program imagery. We generated 30m resolution biomass maps for estuarine and palustrine emergent tidal marshes as indicated by a modified NOAA Coastal Change Analysis Program map for each region. With a mean plant %C of 44.1% (n=1384, 95% C.I.=43.99% - 44.37%) we estimated mean aboveground carbon densities (Mg/ha) and total carbon stocks for each wetland type for each region. Louisiana palustrine emergent marshes had the highest C density (2.67 ±0.08 Mg/ha) of all regions, while San Francisco Bay brackish/saline marshes had the highest C density of all estuarine emergent marshes (2.03 ±0.06 Mg/ha). This modeling and data synthesis effort will allow for aboveground

  8. Polychlorinated biphenyls in two salt marsh sediments of the Venice Lagoon.

    Science.gov (United States)

    Mugnai, Cristian; Giuliani, Silvia; Bellucci, Luca G; Carraro, Claudio; Favotto, Maurizio; Frignani, Mauro

    2011-10-01

    Polychlorinated biphenyls (PCBs) were measured in two dated salt marsh cores of the Venice Lagoon to assess their input chronology and to evaluate the importance of atmospheric deposition as a source. Sampling sites were chosen in order to evidence the differences between areas located leeward and windward with respect to inputs originating in both the city of Venice and the industrial area. Concentrations of PCB indicators (0.13-15.6 ng g⁻¹) increased gradually from the 1930s, reached maxima from the 1950s to the late 1970s, and then decreased. PCB loadings to marshes are driven by both the atmospheric deposition and the resuspension of subtidal sediments, this latter being more important for heavier congeners. The downwind marsh recorded higher fluxes (0.06-9.72 ng cm⁻² year⁻¹) than the upwind one (0.01-0.53 ng cm⁻² year⁻¹). Recent fluxes are rather consistent with bulk deposition measurements. A higher contribution of CB-101 and CB-118 was detected in the intermediate layers of the downwind site, suggesting a different PCB source for the corresponding time interval. In the other marsh, PCBs showed a rather constant composition at all levels (mostly CB-153, CB-138 and CB-180), accounting for a regional influence. Deep layers showed an enrichment of higher chlorinated congeners at both sites, whereas recent samples conserve the patterns typical of surficial and subsurficial subtidal sediments. The scientific approach adopted in this research can be considered as a sort of methodological procedure for the determination of fluxes and pathways of PCBs through the study of marsh cores.

  9. Habitat differentiation vs. isolation-by-distance : the genetic population structure of Elymus athericus in European salt marshes

    NARCIS (Netherlands)

    Bockelmann, AC; Reusch, TBH; Bijlsma, R; Bakker, JP

    We investigated genetic differentiation among populations of the clonal grass Elymus athericus, a common salt-marsh species occurring along the Wadden Sea coast of Europe. While E. athericus traditionally occurs in the high salt marsh, it recently also invaded lower parts of the marsh. In one of the

  10. Understanding Spatial and Temporal Shifts in Blue Carbon, Piermont Marsh, Lower Hudson Estuary, NY

    Science.gov (United States)

    Peteet, D. M.; Nichols, J. E.; Kenna, T. C.; Corbett, E. J.; Allen, K. A.; Newton, R.; Vincent, S.; Haroon, A.; Shumer, M.

    2015-12-01

    Piermont Marsh is a National Estuarine Research Reserve (NERR) protected brackish wetland in the lower Hudson Valley. It serves as a nursery for fish, a coastal buffer in storms, a repository of native wetland species unique to the Hudson, and a paleoenvironmental archive. At risk for disappearance due to rising sea level, we assess the present carbon stores and their spatial and temporal variability through time. Determining the depth of peat in transects throughout Piermont Marsh (41°N, 73°55'W), is one step in reconstructing the stores of carbon in the marsh and how they have shifted over millennia. Through the last decade, we have focused field efforts on probing the depths of the marsh through a series of transects and in acquiring sediment cores from which we establish sedimentation rates and carbon storage through time. AMS C-14 dating, XRF fluorescence, pollen analysis, and Cesium-137 provide chronological control for the sedimentation rates, pollution history, and an understanding of the regional and local shifts in vegetation. C-13 and pollen measurements in selected cores indicate major shifts in local vegetation with coastal eutrophication as the marsh has been invaded, first by Typha angustifolia in the nineteenth century and then by Phragmites australis in the twentieth century up to the present. N-15 measurements indicate a large shift in nitrogen as humans have impacted the marsh. We present a comprehensive, three-dimensional view of the effects of climate, vegetation, and human impact on the carbon storage of Piermont Marsh. This project provided a site for a place- and project-based learning through Lamont-Doherty's Secondary School Field Research Program. Many of the field samples were collected by young investigators from schools in New York City and towns near Piermont.

  11. Maine belowground marsh destruction from the European green crab documented by computer-aided tomography

    Science.gov (United States)

    Invasive European green crab (Carcinus maenus) populations have exploded with devastating losses to Maine’s intertidal resources including soft-shell clams, eelgrass beds, and salt marshes. This project quantified the green crab abundance in three different marsh locations ...

  12. Salt-marsh restoration : evaluating the success of de-embankments in north-west Europe

    NARCIS (Netherlands)

    Wolters, M; Garbutt, A; Bakker, JP

    De-embankment of historically reclaimed salt marshes has become a widespread option for re-creating salt marshes, but to date little information exists on the success of de-embankments. One reason is the absence of pre-defined targets, impeding the measurement of success. In this review, success has

  13. Characterization of bedded salt for storage caverns -- A case study from the Midland Basin, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Hovorka, Susan D.; Nava, Robin

    2000-06-13

    The geometry of Permian bedding salt in the Midland Basin is a product of interaction between depositional facies and postdepositional modification by salt dissolution. Mapping high-frequency cycle patterns in cross section and map view using wireline logs documents the salt geometry. Geologically based interpretation of depositional and dissolution processes provides a powerful tool for mapping and geometry of salt to assess the suitability of sites for development of solution-mined storage caverns. In addition, this process-based description of salt geometry complements existing data about the evolution of one of the best-known sedimentary basins in the world, and can serve as a genetic model to assist in interpreting other salts.

  14. Utility of Ambulance Data for Real-Time Syndromic Surveillance: A Pilot in the West Midlands Region, United Kingdom.

    Science.gov (United States)

    Todkill, Dan; Loveridge, Paul; Elliot, Alex J; Morbey, Roger A; Edeghere, Obaghe; Rayment-Bishop, Tracy; Rayment-Bishop, Chris; Thornes, John E; Smith, Gillian

    2017-12-01

    Introduction The Public Health England (PHE; United Kingdom) Real-Time Syndromic Surveillance Team (ReSST) currently operates four national syndromic surveillance systems, including an emergency department system. A system based on ambulance data might provide an additional measure of the "severe" end of the clinical disease spectrum. This report describes the findings and lessons learned from the development and preliminary assessment of a pilot syndromic surveillance system using ambulance data from the West Midlands (WM) region in England. Hypothesis/Problem Is an Ambulance Data Syndromic Surveillance System (ADSSS) feasible and of utility in enhancing the existing suite of PHE syndromic surveillance systems? An ADSSS was designed, implemented, and a pilot conducted from September 1, 2015 through March 1, 2016. Surveillance cases were defined as calls to the West Midlands Ambulance Service (WMAS) regarding patients who were assigned any of 11 specified chief presenting complaints (CPCs) during the pilot period. The WMAS collected anonymized data on cases and transferred the dataset daily to ReSST, which contained anonymized information on patients' demographics, partial postcode of patients' location, and CPC. The 11 CPCs covered a broad range of syndromes. The dataset was analyzed descriptively each week to determine trends and key epidemiological characteristics of patients, and an automated statistical algorithm was employed daily to detect higher than expected number of calls. A preliminary assessment was undertaken to assess the feasibility, utility (including quality of key indicators), and timeliness of the system for syndromic surveillance purposes. Lessons learned and challenges were identified and recorded during the design and implementation of the system. The pilot ADSSS collected 207,331 records of individual ambulance calls (daily mean=1,133; range=923-1,350). The ADSSS was found to be timely in detecting seasonal changes in patterns of respiratory

  15. Vegetation engineers marsh morphology through multiple competing stable states

    Science.gov (United States)

    Marani, Marco; Da Lio, Cristina; D’Alpaos, Andrea

    2013-01-01

    Marshes display impressive biogeomorphic features, such as zonation, a mosaic of extensive vegetation patches of rather uniform composition, exhibiting sharp transitions in the presence of extremely small topographic gradients. Although generally associated with the accretion processes necessary for marshes to keep up with relative sea level rise, competing environmental constraints, and ecologic controls, zonation is still poorly understood in terms of the underlying biogeomorphic mechanisms. Here we find, through observations and modeling interpretation, that zonation is the result of coupled geomorphological–biological dynamics and that it stems from the ability of vegetation to actively engineer the landscape by tuning soil elevation within preferential ranges of optimal adaptation. We find multiple peaks in the frequency distribution of observed topographic elevation and identify them as the signature of biologic controls on geomorphodynamics through competing stable states modulated by the interplay of inorganic and organic deposition. Interestingly, the stable biogeomorphic equilibria correspond to suboptimal rates of biomass production, a result coherent with recent observations. The emerging biogeomorphic structures may display varying degrees of robustness to changes in the rate of sea level rise and sediment availability, with implications for the overall resilience of marsh ecosystems to climatic changes. PMID:23401529

  16. Seasonal variation in apparent conductivity and soil salinity at two Narragansett Bay salt marshes

    Science.gov (United States)

    Measurement of the apparent conductivity of salt marsh sediments using electromagnetic induction (EMI) is a rapid alternative to traditional methods of salinity determination that can be used to map soil salinity across a marsh surface. Soil salinity measures can provide informat...

  17. Aquatic Insects of New York Salt Marsh Associated with Mosquito Larval Habitat and their Potential Utility as Bioindicators

    OpenAIRE

    Rochlin, Ilia; Dempsey, Mary E.; Iwanejko, Tom; Ninivaggi, Dominick V.

    2011-01-01

    The aquatic insect fauna of salt marshes is poorly characterized, with the possible exception of biting Diptera. Aquatic insects play a vital role in salt marsh ecology, and have great potential importance as biological indicators for assessing marsh health. In addition, they may be impacted by measures to control mosquitoes such as changes to the marsh habitat, altered hydrology, or the application of pesticides. Given these concerns, the goals of this study were to conduct the first taxonom...

  18. Microspatial ecotone dynamics at a shifting range limit: plant-soil variation across salt marsh-mangrove interfaces.

    Science.gov (United States)

    Yando, E S; Osland, M J; Hester, M W

    2018-05-01

    Ecotone dynamics and shifting range limits can be used to advance our understanding of the ecological implications of future range expansions in response to climate change. In the northern Gulf of Mexico, the salt marsh-mangrove ecotone is an area where range limits and ecotone dynamics can be studied in tandem as recent decreases in winter temperature extremes have allowed for mangrove expansion at the expense of salt marsh. In this study, we assessed aboveground and belowground plant-soil dynamics across the salt marsh-mangrove ecotone quantifying micro-spatial patterns in horizontal extent. Specifically, we studied vegetation and rooting dynamics of large and small trees, the impact of salt marshes (e.g. species and structure) on mangroves, and the influence of vegetation on soil properties along transects from underneath the mangrove canopy into the surrounding salt marsh. Vegetation and rooting dynamics differed in horizontal reach, and there was a positive relationship between mangrove tree height and rooting extent. We found that the horizontal expansion of mangrove roots into salt marsh extended up to eight meters beyond the aboveground boundary. Variation in vegetation structure and local hydrology appear to control mangrove seedling dynamics. Finally, soil carbon density and organic matter did not differ within locations across the salt marsh-mangrove interface. By studying aboveground and belowground variation across the ecotone, we can better predict the ecological effects of continued range expansion in response to climate change.

  19. Community structure and abundance of benthic infaunal invertebrates in Maine fringing marsh ecosystems

    Science.gov (United States)

    Richard A. MacKenzie; Michele Dionne; Jeremy Miller; Michael Haas; Pamela A. Morgan

    2015-01-01

    Fringing marshes are abundant ecosystems that dominate the New England coastline. Despite their abundance, very little baseline data is available from them and few studies have documented the ecosystems services that they provide. This information is important for conservation efforts as well as for an increased understanding of how fringing marshes function compared...

  20. Monitoring duration and extent of storm-surge and flooding in Western Coastal Louisiana marshes with Envisat ASAR data

    Science.gov (United States)

    Ramsey, E.; Lu, Z.; Suzuoki, Y.; Rangoonwala, A.; Werle, D.

    2011-01-01

    Inundation maps of coastal marshes in western Louisiana were created with multitemporal Envisat Advanced Synthetic Aperture (ASAR) scenes collected before and during the three months after Hurricane Rita landfall in September 2005. Corroborated by inland water-levels, 7 days after landfall, 48% of coastal estuarine and palustrine marshes remained inundated by storm-surge waters. Forty-five days after landfall, storm-surge inundated 20% of those marshes. The end of the storm-surge flooding was marked by an abrupt decrease in water levels following the passage of a storm front and persistent offshore winds. A complementary dramatic decrease in flood extent was confirmed by an ASAR-derived inundation map. In nonimpounded marshes at elevations ;80 cm during the first month after Rita landfall. After this initial period, drainage from marshes-especially impounded marshes-was hastened by the onset of offshore winds. Following the abrupt drops in inland water levels and flood extent, rainfall events coinciding with increased water levels were recorded as inundation re-expansion. This postsurge flooding decreased until only isolated impounded and palustrine marshes remained inundated. Changing flood extents were correlated to inland water levels and largely occurred within the same marsh regions. Trends related to incremental threshold increases used in the ASAR change-detection analyses seemed related to the preceding hydraulic and hydrologic events, and VV and HH threshold differences supported their relationship to the overall wetland hydraulic condition.

  1. Storm surges and climate change implications for tidal marshes: Insight from the San Francisco Bay Estuary, California, USA

    Science.gov (United States)

    Thorne, Karen M.; Buffington, Kevin J.; Swanson, Kathleen; Takekawa, John Y.

    2013-01-01

    Tidal marshes are dynamic ecosystems, which are influenced by oceanic and freshwater processes and daily changes in sea level. Projected sea-level rise and changes in storm frequency and intensity will affect tidal marshes by altering suspended sediment supply, plant communities, and the inundation duration and depth of the marsh platform. The objective of this research was to evaluate if regional weather conditions resulting in low-pressure storms changed tidal conditions locally within three tidal marshes. We hypothesized that regional storms will increase sea level heights locally, resulting in increased inundation of the tidal marsh platform and plant communities. Using site-level measurements of elevation, plant communities, and water levels, we present results from two storm events in 2010 and 2011 from the San Francisco Bay Estuary (SFBE), California, USA. The January 2010 storm had the lowest recorded sea level pressure in the last 30 years for this region. During the storm episodes, the duration of tidal marsh inundation was 1.8 and 3.1 times greater than average for that time of year, respectively. At peak storm surges, over 65% in 2010 and 93% in 2011 of the plant community was under water. We also discuss the implications of these types of storms and projected sea-level rise on the structure and function of the tidal marshes and how that will impact the hydro-geomorphic processes and marsh biotic communities.

  2. Estimates of future inundation of salt marshes in response to sea-level rise in and around Acadia National Park, Maine

    Science.gov (United States)

    Nielsen, Martha G.; Dudley, Robert W.

    2013-01-01

    Salt marshes are ecosystems that provide many important ecological functions in the Gulf of Maine. The U.S. Geological Survey investigated salt marshes in and around Acadia National Park from Penobscot Bay to the Schoodic Peninsula to map the potential for landward migration of marshes using a static inundation model of a sea-level rise scenario of 60 centimeters (cm; 2 feet). The resulting inundation contours can be used by resource managers to proactively adapt to sea-level rise by identifying and targeting low-lying coastal areas adjacent to salt marshes for conservation or further investigation, and to identify risks to infrastructure in the coastal zone. For this study, the mapping of static inundation was based on digital elevation models derived from light detection and ranging (LiDAR) topographic data collected in October 2010. Land-surveyed control points were used to evaluate the accuracy of the LiDAR data in the study area, yielding a root mean square error of 11.3 cm. An independent accuracy assessment of the LiDAR data specific to salt-marsh land surfaces indicated a root mean square error of 13.3 cm and 95-percent confidence interval of ± 26.0 cm. LiDAR-derived digital elevation models and digital color aerial photography, taken during low tide conditions in 2008, with a pixel resolution of 0.5 meters, were used to identify the highest elevation of the land surface at each salt marsh in the study area. Inundation contours for 60-cm of sea-level rise were delineated above the highest marsh elevation for each marsh. Confidence interval contours (95-percent,± 26.0 cm) were delineated above and below the 60-cm inundation contours, and artificial structures, such as roads and bridges, that may present barriers to salt-marsh migration were mapped. This study delineated 114 salt marshes totaling 340 hectares (ha), ranging in size from 0.11 ha (marshes less than 0.2 ha were mapped only if they were on Acadia National Park property) to 52 ha, with a median

  3. Final report: Initial ecosystem response of salt marshes to ditch plugging and pool creation: Experiments at Rachel Carson National Wildlife Refuge (Maine)

    Science.gov (United States)

    Adamowicz, S.C.; Roman, C.T.

    2002-01-01

    This study evaluates the response of three salt marshes, associated with the Rachel Carson National Wildlife Refuge (Maine), to the practice of ditch plugging. Drainage ditches, originally dug to drain the marsh for mosquito control or to facilitate salt hay farming, are plugged with marsh peat in an effort to impound water upstream of the plug, raise water table levels in the marsh, and increase surface water habitat. At two study sites, Moody Marsh and Granite Point Road Marsh, ditch plugs were installed in spring 2000. Monitoring of hydrology, vegetation, nekton and bird utilization, and marsh development processes was conducted in 1999, before ditch plugging, and then in 2000 and 2001 (all parameters except nekton), after ditch plugging. Each study site had a control marsh that was monitored simultaneously with the plugged marsh, and thus, we employed a BACI study design (before, after, control, impact). A third site, Marshall Point Road Marsh, was plugged in 1998. Monitoring of the plugged and control sites was conducted in 1999 and 2000, with limited monitoring in 2001, thus there was no ?before? plug monitoring. With ditch plugging, water table levels increased toward the marsh surface and the areal extent of standing water increased. Responding to a wetter substrate, a vegetation change from high marsh species (e.g., Spartina patens) to those more tolerant of flooded conditions (e.g., Spartina alterniflora) was noted at two of the three ditch plugged sites. Initial response of the nekton community (fishes and decapod crustaceans) was evaluated by monitoring utilization of salt marsh pools using a 1m2 enclosure trap. In general, nekton species richness, density, and community structure remained unchanged following ditch plugging at the Moody and Granite Point sites. At Marshall Point, species richness and density (number of individuals per m2) were significantly greater in the experimental plugged marsh than the control marsh (<2% of the control marsh was

  4. Improving salt marsh digital elevation model accuracy with full-waveform lidar and nonparametric predictive modeling

    Science.gov (United States)

    Rogers, Jeffrey N.; Parrish, Christopher E.; Ward, Larry G.; Burdick, David M.

    2018-03-01

    Salt marsh vegetation tends to increase vertical uncertainty in light detection and ranging (lidar) derived elevation data, often causing the data to become ineffective for analysis of topographic features governing tidal inundation or vegetation zonation. Previous attempts at improving lidar data collected in salt marsh environments range from simply computing and subtracting the global elevation bias to more complex methods such as computing vegetation-specific, constant correction factors. The vegetation specific corrections can be used along with an existing habitat map to apply separate corrections to different areas within a study site. It is hypothesized here that correcting salt marsh lidar data by applying location-specific, point-by-point corrections, which are computed from lidar waveform-derived features, tidal-datum based elevation, distance from shoreline and other lidar digital elevation model based variables, using nonparametric regression will produce better results. The methods were developed and tested using full-waveform lidar and ground truth for three marshes in Cape Cod, Massachusetts, U.S.A. Five different model algorithms for nonparametric regression were evaluated, with TreeNet's stochastic gradient boosting algorithm consistently producing better regression and classification results. Additionally, models were constructed to predict the vegetative zone (high marsh and low marsh). The predictive modeling methods used in this study estimated ground elevation with a mean bias of 0.00 m and a standard deviation of 0.07 m (0.07 m root mean square error). These methods appear very promising for correction of salt marsh lidar data and, importantly, do not require an existing habitat map, biomass measurements, or image based remote sensing data such as multi/hyperspectral imagery.

  5. Resistance to Phytophthora cinnamomi among seedlings from backcross families of hybrid american chestnut

    Science.gov (United States)

    Steven N. Jeffers; Inga M. Meadows; Joseph B. James; Paul H. Sisco

    2012-01-01

    American chestnut (Castanea dentata (Marsh.) Borkh.) once was a primary hardwood species in forests of the eastern United States. Sometime during the late 18th century, it is speculated that Phytophthora cinnamomi, which causes Phytophthora root rot (PRR) on many woody plant species, was introduced to the southeast region of...

  6. A remote sensing-based model of tidal marsh aboveground carbon stocks for the conterminous United States

    Science.gov (United States)

    Byrd, Kristin B.; Ballanti, Laurel; Thomas, Nathan; Nguyen, Dung; Holmquist, James R.; Simard, Marc; Windham-Myers, Lisamarie

    2018-05-01

    Remote sensing based maps of tidal marshes, both of their extents and carbon stocks, have the potential to play a key role in conducting greenhouse gas inventories and implementing climate mitigation policies. Our objective was to generate a single remote sensing model of tidal marsh aboveground biomass and carbon that represents nationally diverse tidal marshes within the conterminous United States (CONUS). We developed the first calibration-grade, national-scale dataset of aboveground tidal marsh biomass, species composition, and aboveground plant carbon content (%C) from six CONUS regions: Cape Cod, MA, Chesapeake Bay, MD, Everglades, FL, Mississippi Delta, LA, San Francisco Bay, CA, and Puget Sound, WA. Using the random forest machine learning algorithm, we tested whether imagery from multiple sensors, Sentinel-1 C-band synthetic aperture radar, Landsat, and the National Agriculture Imagery Program (NAIP), can improve model performance. The final model, driven by six Landsat vegetation indices and with the soil adjusted vegetation index as the most important (n = 409, RMSE = 310 g/m2, 10.3% normalized RMSE), successfully predicted biomass for a range of marsh plant functional types defined by height, leaf angle and growth form. Model results were improved by scaling field-measured biomass calibration data by NAIP-derived 30 m fraction green vegetation. With a mean plant carbon content of 44.1% (n = 1384, 95% C.I. = 43.99%-44.37%), we generated regional 30 m aboveground carbon density maps for estuarine and palustrine emergent tidal marshes as indicated by a modified NOAA Coastal Change Analysis Program map. We applied a multivariate delta method to calculate uncertainties in regional carbon densities and stocks that considered standard error in map area, mean biomass and mean %C. Louisiana palustrine emergent marshes had the highest C density (2.67 ± 0.004 Mg/ha) of all regions, while San Francisco Bay brackish/saline marshes had the highest C density of all

  7. Below the Disappearing Marshes of an Urban Estuary: Historic Nitrogen Trends and Soil Structure

    Science.gov (United States)

    Marshes in the urban Jamaica Bay Estuary, New York, USA are disappearing at an average rate of 13 ha/yr, and multiple stressors (e.g., wastewater inputs, dredging activities, groundwater removal, and global warming) may be contributing to marsh losses. Among these stressors, wa...

  8. Carbon sequestration by Australian tidal marshes

    KAUST Repository

    Macreadie, Peter I.; Ollivier, Q. R.; Kelleway, J. J.; Serrano, O.; Carnell, P. E.; Lewis, C. J. Ewers; Atwood, T. B.; Sanderman, J.; Baldock, J.; Connolly, R. M.; Duarte, Carlos M.; Lavery, P. S.; Steven, A.; Lovelock, C. E.

    2017-01-01

    ) storage in Australia's tidal marshes (323 cores). OC stocks in the surface 1 m averaged 165.41 (SE 6.96) Mg OC ha-1 (range 14-963 Mg OC ha-1). The mean OC accumulation rate was 0.55 ± 0.02 Mg OC ha-1 yr-1. Geomorphology was the most important predictor

  9. Salt Marsh--Estuarine Ecosystem: A Liquid Asset

    Science.gov (United States)

    Steever, E. Zell

    1977-01-01

    A comprehensive description of the salt marsh-estuarine ecosystem is provided. Topics discussed include: the general geologic history and formation of this ecosystem; physical and chemical parameters; variety; primary productivity; tidal zones; kind, sizes and abundance of vegetation; and the environmental factors influencing vegetation. (BT)

  10. Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI design

    Directory of Open Access Journals (Sweden)

    Dempsey Mary E

    2009-06-01

    Full Text Available Abstract Background In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted habitat modification and biological control methods known as Open Marsh Water Management (OMWM had been proposed as a viable alternative to marsh-wide physical alterations and chemical control. However, traditional larval sampling techniques may not adequately assess the impacts of marsh management on mosquito larvae. To assess the effectiveness of integrated OMWM and marsh restoration techniques for mosquito control, we analyzed the results of a 5-year OMWM/marsh restoration project to determine changes in mosquito larval production using GIS and geostatistical methods. Methods The following parameters were evaluated using "Before-After-Control-Impact" (BACI design: frequency and geographic extent of larval production, intensity of larval production, changes in larval habitat, and number of larvicide applications. The analyses were performed using Moran's I, Getis-Ord, and Spatial Scan statistics on aggregated before and after data as well as data collected over time. This allowed comparison of control and treatment areas to identify changes attributable to the OMWM/marsh restoration modifications. Results The frequency of finding mosquito larvae in the treatment areas was reduced by 70% resulting in a loss of spatial larval clusters compared to those found in the control areas. This effect was observed directly following OMWM treatment and remained significant throughout the study period. The greatly reduced frequency of finding larvae in the treatment

  11. Geostatistical evaluation of integrated marsh management impact on mosquito vectors using before-after-control-impact (BACI) design.

    Science.gov (United States)

    Rochlin, Ilia; Iwanejko, Tom; Dempsey, Mary E; Ninivaggi, Dominick V

    2009-06-23

    In many parts of the world, salt marshes play a key ecological role as the interface between the marine and the terrestrial environments. Salt marshes are also exceedingly important for public health as larval habitat for mosquitoes that are vectors of disease and significant biting pests. Although grid ditching and pesticides have been effective in salt marsh mosquito control, marsh degradation and other environmental considerations compel a different approach. Targeted habitat modification and biological control methods known as Open Marsh Water Management (OMWM) had been proposed as a viable alternative to marsh-wide physical alterations and chemical control. However, traditional larval sampling techniques may not adequately assess the impacts of marsh management on mosquito larvae. To assess the effectiveness of integrated OMWM and marsh restoration techniques for mosquito control, we analyzed the results of a 5-year OMWM/marsh restoration project to determine changes in mosquito larval production using GIS and geostatistical methods. The following parameters were evaluated using "Before-After-Control-Impact" (BACI) design: frequency and geographic extent of larval production, intensity of larval production, changes in larval habitat, and number of larvicide applications. The analyses were performed using Moran's I, Getis-Ord, and Spatial Scan statistics on aggregated before and after data as well as data collected over time. This allowed comparison of control and treatment areas to identify changes attributable to the OMWM/marsh restoration modifications. The frequency of finding mosquito larvae in the treatment areas was reduced by 70% resulting in a loss of spatial larval clusters compared to those found in the control areas. This effect was observed directly following OMWM treatment and remained significant throughout the study period. The greatly reduced frequency of finding larvae in the treatment areas led to a significant decrease (approximately 44%) in

  12. Sears Point Tidal Marsh Restoration Project: Phase II

    Science.gov (United States)

    Information about the SFBWQP Sears Point Tidal Marsh Restoration Project: Phase II, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  13. Avian communities in tidal salt marshes of San Francisco Bay: a review of functional groups by foraging guild and habitat association

    Science.gov (United States)

    Takekawa, John Y.; Woo, Isa; Gardiner, Rachel J.; Casazza, Michael L.; Ackerman, Joshua T.; Nur, Nadav; Liu, Leonard; Spautz, Hildie; Palaima, Arnas

    2011-01-01

    The San Francisco Bay estuary is highly urbanized, but it supports the largest remaining extent of tidal salt marshes on the west coast of North America as well as a diverse native bird community. San Francisco Bay tidal marshes are occupied by more than 113 bird species that represent 31 families, including five subspecies from three families that we denote as tidal-marsh obligates. To better identify the niche of bird species in tidal marshes, we present a review of functional groups based on foraging guilds and habitat associations. Foraging guilds describe the method by which species obtain food from tidal marshes, while habitat associations describe broad areas within the marsh that have similar environmental conditions. For example, the ubiquitous song sparrows (Alameda Melospiza melodia pusillula, Suisun M. m. maxillaris, and San Pablo M. m. samuelis) are surface-feeding generalists that consume prey from vegetation and the ground, and they are found across the entire marsh plain into the upland–marsh transition. In contrast, surface-feeding California black rails (Laterallus jamaicensis coturniculus) are cryptic, and generally restricted in their distribution to the mid- and high-marsh plain. Although in the same family, the endangered California clapper rail (Rallus longirostris obsoletus) has become highly specialized, foraging primarily on benthic fauna within marsh channels when they are exposed at low tide. Shorebirds such as the black-necked stilt (Himantopus mexicanus) typically probe in mud flats to consume macroinvertebrate prey, and are generally restricted to foraging on salt pans within the marsh plain, in ponds, or on mud flats during transitional stages of marsh evolution. The abundance and distribution of birds varies widely with changing water depths and vegetation colonization during different stages of restoration. Thus, tidal-marsh birds represent a rich and diverse community in bay marshes, with niches that may be distinguished by the

  14. Behaviour of horses and cattle at two stocking densities in a coastal salt marsh

    NARCIS (Netherlands)

    Nolte, S.; Weyde, van der C.; Esselink, P.; Smit, C.; Wieren, van S.E.; Bakker, J.P.

    2017-01-01

    Livestock grazing has been practiced in salt marshes in the Wadden Sea area since 600 B.C. Currently livestock grazing is also applied for conservation management. However, effects of such grazing management on salt marshes are likely to vary depending on the species of livestock and stocking

  15. Behaviour of horses and cattle at two stocking densities in a coastal salt marsh

    NARCIS (Netherlands)

    Nolte, S.; Van der Weyde, C; Esselink, Peter; Smit, C.; Van Wieren, S.E.; Bakker, Jan P.

    Livestock grazing has been practiced in salt marshes in the Wadden Sea area since 600 B.C. Currently livestock grazing is also applied for conservation management. However, effects of such grazing management on salt marshes are likely to vary depending on the species of livestock and stocking

  16. POTENTIAL FOR THE DEVELOPMENT OF MARSH VEGETATION FROM THE SEED BANK AFTER A DRAWDOWN

    NARCIS (Netherlands)

    TERHEERDT, GNJ; DROST, HJ

    1994-01-01

    In the inundated part of the Oostvaardersplassen, a marsh in The Netherlands, most of the emergent vegetation disappeared due to herbivory and erosion, resulting in a shallow lake. The emergent vegetation was successfully re-established by means of a drawdown. A comparable flooded marsh was studied

  17. Sears Point Tidal Marsh Restoration Project: Phase I

    Science.gov (United States)

    Information about the SFBWQP Sears Point Tidal Marsh Restoration Project: Phase I project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  18. Delineation of marsh types of the Texas coast from Corpus Christi Bay to the Sabine River in 2010

    Science.gov (United States)

    Enwright, Nicholas M.; Hartley, Stephen B.; Brasher, Michael G.; Visser, Jenneke M.; Mitchell, Michael K.; Ballard, Bart M.; Parr, Mark W.; Couvillion, Brady R.; Wilson, Barry C.

    2014-01-01

    Coastal zone managers and researchers often require detailed information regarding emergent marsh vegetation types for modeling habitat capacities and needs of marsh-reliant wildlife (such as waterfowl and alligator). Detailed information on the extent and distribution of marsh vegetation zones throughout the Texas coast has been historically unavailable. In response, the U.S. Geological Survey, in cooperation and collaboration with the U.S. Fish and Wildlife Service via the Gulf Coast Joint Venture, Texas A&M University-Kingsville, the University of Louisiana-Lafayette, and Ducks Unlimited, Inc., has produced a classification of marsh vegetation types along the middle and upper Texas coast from Corpus Christi Bay to the Sabine River. This study incorporates approximately 1,000 ground reference locations collected via helicopter surveys in coastal marsh areas and about 2,000 supplemental locations from fresh marsh, water, and “other” (that is, nonmarsh) areas. About two-thirds of these data were used for training, and about one-third were used for assessing accuracy. Decision-tree analyses using Rulequest See5 were used to classify emergent marsh vegetation types by using these data, multitemporal satellite-based multispectral imagery from 2009 to 2011, a bare-earth digital elevation model (DEM) based on airborne light detection and ranging (lidar), alternative contemporary land cover classifications, and other spatially explicit variables believed to be important for delineating the extent and distribution of marsh vegetation communities. Image objects were generated from segmentation of high-resolution airborne imagery acquired in 2010 and were used to refine the classification. The classification is dated 2010 because the year is both the midpoint of the multitemporal satellite-based imagery (2009–11) classified and the date of the high-resolution airborne imagery that was used to develop image objects. Overall accuracy corrected for bias (accuracy

  19. Transport of mecoprop from agricultural soils to an adjacent salt marsh

    International Nuclear Information System (INIS)

    Fletcher, Caroline A.; Scrimshaw, Mark D.; Lester, John N.

    2004-01-01

    Salt marshes are important ecological areas and play a significant role in coastal flood defence schemes. In many areas of the UK they are adjacent to agricultural areas utilised for the growth of cereal crops, for which mecoprop is used as a selective herbicide in the control of broad-leafed weeds. This study measured concentrations of mecoprop in soils, drainage ditch waters and sediments and salt marsh sediments over a period of 138 days following spring application. Soil concentrations of up to 1827 μg/g were recorded after application, which demonstrated a half life for mecoprop of from 9 to 12 days, with first order kinetics. However, a major rainfall event 9 days after application resulted in significant transport of herbicide to the salt marsh via subsurface field drains, drainage ditches and discharge sluice. Mecoprop concentrations of up to 386 μg/l observed in water samples were above UK guidelines

  20. Tidal Marshes across a Chesapeake Bay Subestuary Are Not Keeping up with Sea-Level Rise.

    Science.gov (United States)

    Beckett, Leah H; Baldwin, Andrew H; Kearney, Michael S

    2016-01-01

    Sea-level rise is a major factor in wetland loss worldwide, and in much of Chesapeake Bay (USA) the rate of sea-level rise is higher than the current global rate of 3.2 mm yr-1 due to regional subsidence. Marshes along estuarine salinity gradients differ in vegetation composition, productivity, decomposition pathways, and sediment dynamics, and may exhibit different responses to sea-level rise. Coastal marshes persist by building vertically at rates at or exceeding regional sea-level rise. In one of the first studies to examine elevation dynamics across an estuarine salinity gradient, we installed 15 surface elevation tables (SET) and accretion marker-horizon plots (MH) in tidal freshwater, oligohaline, and brackish marshes across a Chesapeake Bay subestuary. Over the course of four years, wetlands across the subestuary decreased 1.8 ± 2.7 mm yr-1 in elevation on average, at least 5 mm yr-1 below that needed to keep pace with global sea-level rise. Elevation change rates did not significantly differ among the marshes studied, and ranged from -9.8 ± 6.9 to 4.5 ± 4.3 mm yr-1. Surface accretion of deposited mineral and organic matter was uniformly high across the estuary (~9-15 mm yr-1), indicating that elevation loss was not due to lack of accretionary input. Position in the estuary and associated salinity regime were not related to elevation change or surface matter accretion. Previous studies have focused on surface elevation change in marshes of uniform salinity (e.g., salt marshes); however, our findings highlight the need for elevation studies in marshes of all salinity regimes and different geomorphic positions, and warn that brackish, oligohaline, and freshwater tidal wetlands may be at similarly high risk of submergence in some estuaries.

  1. Assessment of metal and trace element contamination in water, sediment, plants, macroinvertebrates, and fish in Tavasci Marsh, Tuzigoot National Monument, Arizona

    Science.gov (United States)

    Beisner, Kimberly R.; Paretti, Nicholas V.; Brasher, Anne M.D.; Fuller, Christopher C.; Miller, Matthew P.

    2014-01-01

    Tavasci Marsh is a large freshwater marsh within the Tuzigoot National Monument in central Arizona. It is the largest freshwater marsh in Arizona that is unconnected to the Colorado River and is designated as an Important Bird Area by the Audubon Society. The marsh has been altered significantly by previous land use and the monument’s managers are evaluating the restoration of the marsh. In light of historical mining activities located near the marsh from the first half of the 20th century, evaluations of water, sediment, plant, and aquatic biota in the marsh were conducted. The evaluations were focused on nine metals and trace elements commonly associated with mining and other anthropogenic activities (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, and Zn) together with isotopic analyses to understand the presence, sources and timing of water and sediment contaminants to the marsh and the occurrence in aquatic plants, dragonfly larvae, and fish. Results of water analyses indicate that there were two distinct sources of water contributing to the marsh during the study: one from older high elevation recharge entering the marsh at Shea Spring (as well as a number of unnamed seeps and springs on the northeastern edge of the marsh) and the other from younger low elevation recharge or from Pecks Lake. Water concentrations for arsenic exceeded the U.S. Environmental Protection Agency primary drinking water standard of 10 μg/L at all sampling sites. Surface waters at Tavasci Marsh may contain conditions favorable for methylmercury production. All surficial and core sediment samples exceeded or were within sample concentration variability of at least one threshold sediment quality guideline for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn. Several sediment sites were also above or were within sample concentration variability of severe or probable effect sediment quality guidelines for As, Cd, and Cu. Three sediment cores collected in the marsh have greater metal and trace element concentrations

  2. Plant distribution and stand characteristics in brackish marshes: Unravelling the roles of abiotic factors and interspecific competition

    Science.gov (United States)

    Carus, Jana; Heuner, Maike; Paul, Maike; Schröder, Boris

    2017-09-01

    Due to increasing pressure on estuarine marshes from sea level rise and river training, there is a growing need to understand how species-environment relationships influence the zonation and growth of tidal marsh vegetation. In the present study, we investigated the distribution and stand characteristics of the two key brackish marsh species Bolboschoenus maritimus and Phragmites australis in the Elbe estuary together with several abiotic habitat factors. We then tested the effect of these habitat factors on plant growth and zonation with generalised linear models (GLMs). Our study provides detailed information on the importance of single habitat factors and their interactions for controlling the distribution patterns and stand characteristics of two key marsh species. Our results suggest that flow velocity is the main factor influencing species distribution and stand characteristics and together with soil-water salinity even affects the inundation tolerance of the two specie investigated here. Additionally, inundation height and duration as well as interspecific competition helped explain the distribution patterns and stand characteristics. By identifying the drivers of marsh zonation and stand characteristics and quantifying their effects, this study provides useful information for evaluating a future contribution of tidal marsh vegetation to ecosystem-based shore protection.

  3. Where in the Marsh is the Water (and When)?: Measuring and modeling salt marsh hydrology for ecological and biogeochemical applications

    Science.gov (United States)

    Salt marsh hydrology presents many difficulties from a measurement and modeling standpoint: the bi-directional flows of tidal waters, variable water densities due to mixing of fresh and salt water, significant influences from vegetation, and complex stream morphologies. Because o...

  4. Mangrove expansion into salt marshes alters associated faunal communities

    Science.gov (United States)

    Smee, Delbert L.; Sanchez, James A.; Diskin, Meredith; Trettin, Carl

    2017-03-01

    Climate change is altering the distribution of foundation species, with potential effects on organisms that inhabit these environments and changes to valuable ecosystem functions. In the Gulf of Mexico, black mangroves (Avicennia germinans) are expanding northward into salt marshes dominated by Spartina alterniflora (hereafter Spartina). Salt marshes are essential habitats for many organisms, including ecologically and economically important species such as blue crabs (Callinectes sapidus) and Penaeid shrimp (e.g., Penaeus aztecus), which may be affected by vegetation changes. Black mangroves occupied higher tidal elevations than Spartina, and Spartina was present only at its lowest tidal elevations in sites when mangroves were established. We compared nekton and infaunal communities within monoculture stands of Spartina that were bordered by mangroves to nearby areas where mangroves had not yet become established. Nekton and infaunal communities were significantly different in Spartina stands bordered by mangroves, even though salinity and temperature were not different. Overall abundance and biomass of nekton and infauna was significantly higher in marshes without mangroves, although crabs and fish were more abundant in mangrove areas. Black mangrove expansion as well as other ongoing vegetation shifts will continue in a warming climate. Understanding how these changes affect associated species is necessary for management, mitigation, and conservation.

  5. Strong tidal modulation of net ecosystem exchange in a salt marsh in North Inlet, South Carolina

    Science.gov (United States)

    O'Halloran, T. L.; Smith, E. M.; Bogoev, I.

    2017-12-01

    Along the southeastern US, intertidal salt marshes represent a critical habitat at the interface of the terrestrial and marine environments and perform a variety of ecological functions and services that make them of great economic importance for coastal communities They provide essential fish and shellfish habitat, with a majority of all commercially- and recreationally important fish species being dependent on intertidal marsh habitat during some portion of their life cycle. The penaeid shrimp industry, South Carolina's most economically important fishery, would cease to exist without the critical nursery function provided by intertidal salt marshes. Smooth cordgrass (Spartina alterniflora) is a keystone species in the high salinity marshes of the southeastern U.S., and its functioning is essential to the health and survival of salt marshes under rising sea levels. To better quantify and facilitate prediction of future salt marsh productivity, in May of 2017, we established a new integrated eddy covariance tower system to measure the net ecosystem exchange of carbon in a salt marsh in coastal South Carolina. The tower site is co-located with long-term, ongoing measurements as part of the North Inlet-Winyah Bay National Estuarine Research Reserve (NI-WB NERR). Current sampling conducted within the eddy flux footprint includes: annual measures of the vegetation community at the time of peak biomass; bi-monthly measures of sediment elevation at Sediment Elevation Tables (SETs) located at the upper and lower ends of the flux footprint; monthly sediment porewater salinity and nutrient (ammonium, orthophosphate) and sulfide concentrations; and biannual sediment elevation surveys by RTK-GPS. A suite of water quality measurements are made every 15 minutes in the main creek that floods the marsh platform in the flux footprint. Here we present our first six months of observations investigating the abiotic drivers of productivity on daily (intratidal) to monthly timescales

  6. Influence of Black Mangrove Expansion on Salt Marsh Food Web Dynamics in Coastal Louisiana

    Science.gov (United States)

    Powell, C.; Baustian, M. M.; Polito, M. J.

    2017-12-01

    The range of black mangroves (Avicennia germinans) is projected to expand in the northern Gulf of Mexico due to reduced winter freeze events and an increased rate of droughts. The colonization of mangroves in salt marshes alters habitat structure and creates a novel basal carbon source for consumers. This addition may modify trophic linkages and the structure of estuarine food webs. To understand the implications of mangrove expansion on food web dynamics of traditional Spartina alterniflora marshes, two sites in coastal Louisiana with three habitat types, marsh-dominated, mangrove-dominated, and a transition or mix of the two, were studied. Community composition of juvenile nekton was sampled using fyke nets, minnow traps, and suction sampling and analyzed for abundance and diversity. Primary carbon sources (emergent vegetation, phytoplankton, macroalgae, benthic microalgae, submerged aquatic vegetation, and soil organic matter) and consumers ((blue crabs (Callinectes sapidus), brown shrimp (Farfantepenaeus aztecus), grass shrimp (Palaemonetes spp.), Gulf killifish (Fundulus grandis), periwinkle snails (Littoraria irrorata), eastern oysters (Crassostrea virginica), and southern ribbed mussels (Geukensia granosissima)) collected at each habitat type were measured using stable isotope analysis (δ13C, δ15N, δ34S) to identify trophic level, basal carbon sources, and assess how mangrove carbon is incorporated into salt marsh food webs. While data analysis is ongoing, preliminary results indicate that basal carbon sources supporting some marsh consumers (e.g., periwinkle snails) shift between habitat types, while others remain static (e.g., grass shrimp). This research will further develop our understanding of how climate induced shifts in vegetation influences valued marsh-dependent consumers in the estuarine ecosystems of northern Gulf of Mexico.

  7. Evaluating tidal marsh sustainability in the face of sea-level rise: a hybrid modeling approach applied to San Francisco Bay.

    Directory of Open Access Journals (Sweden)

    Diana Stralberg

    Full Text Available Tidal marshes will be threatened by increasing rates of sea-level rise (SLR over the next century. Managers seek guidance on whether existing and restored marshes will be resilient under a range of potential future conditions, and on prioritizing marsh restoration and conservation activities.Building upon established models, we developed a hybrid approach that involves a mechanistic treatment of marsh accretion dynamics and incorporates spatial variation at a scale relevant for conservation and restoration decision-making. We applied this model to San Francisco Bay, using best-available elevation data and estimates of sediment supply and organic matter accumulation developed for 15 Bay subregions. Accretion models were run over 100 years for 70 combinations of starting elevation, mineral sediment, organic matter, and SLR assumptions. Results were applied spatially to evaluate eight Bay-wide climate change scenarios.Model results indicated that under a high rate of SLR (1.65 m/century, short-term restoration of diked subtidal baylands to mid marsh elevations (-0.2 m MHHW could be achieved over the next century with sediment concentrations greater than 200 mg/L. However, suspended sediment concentrations greater than 300 mg/L would be required for 100-year mid marsh sustainability (i.e., no elevation loss. Organic matter accumulation had minimal impacts on this threshold. Bay-wide projections of marsh habitat area varied substantially, depending primarily on SLR and sediment assumptions. Across all scenarios, however, the model projected a shift in the mix of intertidal habitats, with a loss of high marsh and gains in low marsh and mudflats.Results suggest a bleak prognosis for long-term natural tidal marsh sustainability under a high-SLR scenario. To minimize marsh loss, we recommend conserving adjacent uplands for marsh migration, redistributing dredged sediment to raise elevations, and concentrating restoration efforts in sediment-rich areas

  8. Facilitation of American chestnut (Castanea dentata) seedling establishment by Pinus virginiana in mine restoration

    Science.gov (United States)

    Jenise M. Bauman; Carolyn H. Keiffer; Shiv. Hiremath

    2012-01-01

    This study evaluated the influence of planting sites on the establishment and ectomycorrhizal (ECM) colonization of American chestnut (Castanea denetata (Marsh.) Borkh.) on an abandoned coal mine in an Appalachian region of the United States. Root morphotyping and sequencing of the fungal internal transcribed spacer (ITS) region were used to identify...

  9. How do how internal and external processes affect the behaviors of coupled marsh mudflat systems; infill, stabilize, retreat, or drown?

    Science.gov (United States)

    Carr, J. A.; Mariotti, G.; Wiberg, P.; Fagherazzi, S.; McGlathery, K.

    2013-12-01

    Intertidal coastal environments are prone to changes induced by sea level rise, increases in storminess, and anthropogenic disturbances. It is unclear how changes in external drivers may affect the dynamics of low energy coastal environments because their response is non-linear, and characterized by many thresholds and discontinuities. As such, process-based modeling of the ecogeomorphic processes underlying the dynamics of these ecosystems is useful, not only to predict their change through time, but also to generate new hypotheses and research questions. Here, a three-point dynamic model was developed to investigate how internal and external processes affect the behavior of coupled marsh mudflat systems. The model directly incorporates ecogeomorphological feedbacks between wind waves, salt marsh vegetation, allochthonous sediment loading, tidal flat vegetation and sea level rise. The model was applied to examine potential trajectories of salt marshes on the Eastern seaboard of the United States, including those in the Plum Island Ecosystems (PIE), Virginia Coast Reserve (VCR) and Georgia Coastal Ecosystems (GCE) long term ecological research (LTER) sites. While these sites are undergoing similar rates of relative sea level rise (RSLR), they have distinct differences in site specific environmental drivers including tides, wind waves, allochthonous sediment supply and the presence or absence of seagrass. These differences lead to the emergence of altered behaviors in the coupled salt marsh-tidal flat system. For marsh systems without seagrass or significant riverine sediment supply, conditions similar to those at PIE, results indicated that horizontal and vertical marsh evolution respond in opposing ways to wave induced processes. Marsh horizontal retreat is triggered by large mudflats and strong winds, whereas small mudflats and weak winds reduce the sediment supply to the salt marsh, decreasing its capability to keep pace with sea level rise. Marsh expansion and

  10. Vegetation - Suisun Marsh, Change 1999 to 2000 [ds163

    Data.gov (United States)

    California Natural Resource Agency — This vegetation mapping project of Suisun Marsh blends ground-based classification, aerial photo interpretation, and GIS editing and processing. The method is based...

  11. Vegetation - Suisun Marsh, Change 1999 to 2003 [ds164

    Data.gov (United States)

    California Natural Resource Agency — This vegetation mapping project of Suisun Marsh blends ground-based classification, aerial photo interpretation, and GIS editing and processing. The method is based...

  12. Marsh soil responses to tidal water nitrogen additions contribute to creek bank fracturing and slumping

    Science.gov (United States)

    Large-scale dissolved nutrient enrichment can cause a reduction in belowground biomass, increased water content of soils, and increased microbial decomposition, which has been linked with slumping of low marsh Spartina vegetation into creeks, and ultimately marsh loss. Our study ...

  13. A remote sensing-based model of tidal marsh aboveground carbon stocks for the conterminous United States

    Science.gov (United States)

    Byrd, Kristin B.; Ballanti, Laurel; Thomas, Nathan; Nguyen, Dung; Holmquist, James R.; Simard, Marc; Windham-Myers, Lisamarie

    2018-01-01

    Remote sensing based maps of tidal marshes, both of their extents and carbon stocks, have the potential to play a key role in conducting greenhouse gas inventories and implementing climate mitigation policies. Our objective was to generate a single remote sensing model of tidal marsh aboveground biomass and carbon that represents nationally diverse tidal marshes within the conterminous United States (CONUS). We developed the first calibration-grade, national-scale dataset of aboveground tidal marsh biomass, species composition, and aboveground plant carbon content (%C) from six CONUS regions: Cape Cod, MA, Chesapeake Bay, MD, Everglades, FL, Mississippi Delta, LA, San Francisco Bay, CA, and Puget Sound, WA. Using the random forest machine learning algorithm, we tested whether imagery from multiple sensors, Sentinel-1 C-band synthetic aperture radar, Landsat, and the National Agriculture Imagery Program (NAIP), can improve model performance. The final model, driven by six Landsat vegetation indices and with the soil adjusted vegetation index as the most important (n = 409, RMSE = 310 g/m2, 10.3% normalized RMSE), successfully predicted biomass for a range of marsh plant functional types defined by height, leaf angle and growth form. Model results were improved by scaling field-measured biomass calibration data by NAIP-derived 30 m fraction green vegetation. With a mean plant carbon content of 44.1% (n = 1384, 95% C.I. = 43.99%–44.37%), we generated regional 30 m aboveground carbon density maps for estuarine and palustrine emergent tidal marshes as indicated by a modified NOAA Coastal Change Analysis Program map. We applied a multivariate delta method to calculate uncertainties in regional carbon densities and stocks that considered standard error in map area, mean biomass and mean %C. Louisiana palustrine emergent marshes had the highest C density (2.67 ± 0.004 Mg/ha) of all regions, while San Francisco Bay brackish/saline marshes had

  14. Response of gaseous carbon emissions to low-level salinity increase in tidal marsh ecosystem of the Min River estuary, southeastern China.

    Science.gov (United States)

    Hu, Minjie; Ren, Hongchang; Ren, Peng; Li, Jiabing; Wilson, Benjamin J; Tong, Chuan

    2017-02-01

    Although estuarine tidal marshes are important contributors to the emission of greenhouse gases into the atmosphere, the relationship between carbon dioxide (CO 2 ), methane (CH 4 ) emission, and environmental factors, with respect to estuarine marshes, has not been clarified thoroughly. This study investigated the crucial factors controlling the emission of CO 2 and CH 4 from a freshwater marsh and a brackish marsh located in a subtropical estuary in southeastern China, as well as their magnitude. The duration of the study period was November 2013 to October 2014. Relevant to both the field and incubation experiments, the CO 2 and CH 4 emissions from the two marshes showed pronounced seasonal variations. The CO 2 and CH 4 emissions from both marshes demonstrated significant positive correlations with the air/soil temperature (pemissions between the freshwater and brackish marshes in the subtropical estuary, whereas there was a difference in the CH 4 emissions between the two sites (pemissions from the estuarine freshwater marshes, these factors had little effect on the CO 2 emissions with respect to an increase in salinity of less than 5‰. The findings of this study could have important implications for estimating the global warming contributions of estuarine marshes along differing salinity gradients. Copyright © 2016. Published by Elsevier B.V.

  15. Composition of Fish Communities in a European Macrotidal Salt Marsh (the Mont Saint-Michel Bay, France)

    Science.gov (United States)

    Laffaille, P.; Feunteun, E.; Lefeuvre, J.-C.

    2000-10-01

    At least 100 fish species are known to be present in the intertidal areas (estuaries, mudflats and salt marshes) of Mont Saint-Michel Bay. These and other comparable shallow marine coastal waters, such as estuaries and lagoons, play a nursery role for many fish species. However, in Europe little attention has been paid to the value of tidal salt marshes for fishes. Between March 1996 and April 1999, 120 tides were sampled in a tidal creek. A total of 31 species were caught. This community was largely dominated by mullets ( Liza ramada represent 87% of the total biomass) and sand gobies ( Pomatoschistus minutus and P. lozanoi represent 82% of the total numbers). These species and also Gasterosteus aculeatus , Syngnathus rostellatus, Dicentrarchus labrax, Mugil spp., Liza aurata and Sprattus sprattus were the most frequent species (>50% of monthly frequency of occurrence). In Europe, salt marshes and their creeks are flooded only during high spring tides. So, fishes only invade this environment during short immersion periods, and no species can be considered as marsh resident. But, the salt marsh was colonized by fish every time the tide reached the creek, and during the short time of flood, dominant fishes fed actively and exploited the high productivity. Nevertheless, this study shows that there is little interannual variation in the fish community and there are three ' seasons ' in the fish fauna of the marsh. Marine straggler and marine estuarine dependent species colonize marshes between spring (recruitment period in the bay) and autumn before returning into deeper adjacent waters. Estuarine fishes are present all year round with maximum abundances in the end of summer. The presence of fishes confirms that this kind of wetland plays an important trophic and nursery role for these species. Differences in densities and stages distribution of these species into Mont Saint-Michel systems (tidal mudflats, estuaries and tidal salt marshes) can reduce the trophic

  16. Effects of disturbance associated with seismic exploration for oil and gas reserves in coastal marshes

    Science.gov (United States)

    Howard, Rebecca J.; Wells, Christopher J.; Michot, Thomas C.; Johnson, Darren J.

    2014-01-01

    Anthropogenic disturbances in wetland ecosystems can alter the composition and structure of plant assemblages and affect system functions. Extensive oil and gas extraction has occurred in wetland habitats along the northern Gulf of Mexico coast since the early 1900s. Activities involved with three-dimensional (3D) seismic exploration for these resources cause various disturbances to vegetation and soils. We documented the impact of a 3D seismic survey in coastal marshes in Louisiana, USA, along transects established before exploration began. Two semi-impounded marshes dominated by Spartina patens were in the area surveyed. Vegetation, soil, and water physicochemical data were collected before the survey, about 6 weeks following its completion, and every 3 months thereafter for 2 years. Soil cores for seed bank emergence experiments were also collected. Maximum vegetation height at impact sites was reduced in both marshes 6 weeks following the survey. In one marsh, total vegetation cover was also reduced, and dead vegetation cover increased, at impact sites 6 weeks after the survey. These effects, however, did not persist 3 months later. No effects on soil or water properties were identified. The total number of seeds that germinated during greenhouse studies increased at impact sites 5 months following the survey in both marshes. Although some seed bank effects persisted 1 year, these effects were not reflected in standing vegetation. The marshes studied were therefore resilient to the impacts resulting from 3D seismic exploration because vegetation responses were short term in that they could not be identified a few months following survey completion.

  17. Effects of Disturbance Associated With Seismic Exploration for Oil and Gas Reserves in Coastal Marshes

    Science.gov (United States)

    Howard, Rebecca J.; Wells, Christopher J.; Michot, Thomas C.; Johnson, Darren J.

    2014-07-01

    Anthropogenic disturbances in wetland ecosystems can alter the composition and structure of plant assemblages and affect system functions. Extensive oil and gas extraction has occurred in wetland habitats along the northern Gulf of Mexico coast since the early 1900s. Activities involved with three-dimensional (3D) seismic exploration for these resources cause various disturbances to vegetation and soils. We documented the impact of a 3D seismic survey in coastal marshes in Louisiana, USA, along transects established before exploration began. Two semi-impounded marshes dominated by Spartina patens were in the area surveyed. Vegetation, soil, and water physicochemical data were collected before the survey, about 6 weeks following its completion, and every 3 months thereafter for 2 years. Soil cores for seed bank emergence experiments were also collected. Maximum vegetation height at impact sites was reduced in both marshes 6 weeks following the survey. In one marsh, total vegetation cover was also reduced, and dead vegetation cover increased, at impact sites 6 weeks after the survey. These effects, however, did not persist 3 months later. No effects on soil or water properties were identified. The total number of seeds that germinated during greenhouse studies increased at impact sites 5 months following the survey in both marshes. Although some seed bank effects persisted 1 year, these effects were not reflected in standing vegetation. The marshes studied were therefore resilient to the impacts resulting from 3D seismic exploration because vegetation responses were short term in that they could not be identified a few months following survey completion.

  18. Factors associated with male involvement in the prevention of mother to child transmission of HIV, Midlands Province, Zimbabwe, 2015 - a case control study

    Directory of Open Access Journals (Sweden)

    Annamercy Makoni

    2016-04-01

    Full Text Available Abstract Background Uptake of and adherence to the prevention of mother to child transmission of HIV (PMTCT interventions are a challenge to most women if there is no male partner involvement. Organizations which include the National AIDS Council and the Zimbabwe AIDS Prevention Project- University of Zimbabwe have been working towards mobilizing men for couple HIV testing and counseling (HTC in antenatal care (ANC. In 2013, Midlands province had 19 % males who were tested together with their partners in ANC, an increase by 9 % from 2011. However, this improvement was still far below the national target, hence this study was conducted to determine the associated factors. Methods A1:1 unmatched case control study was conducted. A case was a man who did not receive HIV testing and counseling together with his pregnant wife in ANC in Midlands province from January to June 2015. A control was a man who received HIV testing and counseling together with his pregnant wife in ANC in Midlands province from January to June 2015. Simple random sampling was used to select 112 cases and 112 controls. Epi Info statistical software was used to analyze data. Written informed consent was obtained from each study participant. Results Independent factors that predicted male involvement in PMTCT were: having been previously tested as a couple (aOR 0.22, 95 % CI = 0.12, 0.41 and having time to visit the clinic (aOR 0.41, 95 % CI = 0.21, 0.80. Being afraid of knowing one’s HIV status (aOR 2.22, 95 % CI = 1.04, 4.76 was independently associated with low male involvement in PMTCT. Conclusion Multiple factors were found to be associated with male involvement in PMTCT. Routine PMTCT educational campaigns in places where men gather, community based couple HTC and accommodating the working class during weekends are essential in fostering male involvement in PMTCT thereby reducing HIV transmission to the baby.

  19. Comparison of vesicular-arbuscular mycorrhizae in plants from disturbed and adjacent undisturbed regions of a coastal salt marsh in Clinton, Connecticut, USA

    Science.gov (United States)

    Cooke, John C.; Lefor, Michael W.

    1990-01-01

    Roots of salt marsh plant species Spartina alterniflora, S. patens, Distichlis spicata, and others were examined for the presence of vesicular-arbuscular mycorrhizal (VAM) fungi. Samples were taken from introduced planted material in a salt marsh restoration project and from native material in adjacent marsh areas along the Indian River, Clinton, Connecticut, USA. After ten years the replanted area still has sites devoid of vegetation. The salt marsh plants introduced there were devoid of VAM fungi, while high marsh species from the adjacent undisturbed region showed consistent infection, leading the authors to suggest that VAM fungal infection of planting stocks may be a factor in the success of marsh restoration.

  20. Effects of coastal marsh conversion to shrimp aquaculture ponds on CH4 and N2O emissions

    Science.gov (United States)

    Yang, P.; Bastviken, D.; Lai, D. Y. F.; Jin, B. S.; Mou, X. J.; Tong, C.; Yao, Y. C.

    2017-12-01

    In this study, we compared the CH4 and N2O fluxes from a tidal brackish Cyperus malaccensis marsh ecosystem and nearby shrimp ponds, converted from C. malaccensis marsh in the last 3-4 years, in the Min River estuary of southeast China over the aquaculture period of the year. Significant differences in CH4 and N2O fluxes were observed in space (between brackish marsh and shrimp ponds) and in time (between sampling occasions that were distributed over the aquaculture period). CH4 fluxes from the shrimp ponds were on an average 10-fold higher than from the brackish marsh. N2O emissions, on the other hand, were lower from the shrimp pond (25% of the emissions from the brackish marsh). Accessory data indicates that these patterns were primarily linked to water level variability and temperature (all fluxes), sediment porewater sulfate concentrations (CH4 flux) and total nitrogen concentrations (N2O flux). Our research demonstrates that the coastal marsh ecosystem converted to aquaculture ponds considerably alter emissions of CH4 and N2O and provides input to the global discussion on how to account for emissions from various types of flooded land in greenhouse gas inventories.

  1. Natural and Anthropogenic Causes of Accelerated Sediment Accumulation Rates in Nehalem Bay Salt Marshes, Oregon

    Science.gov (United States)

    Molino, G. D.; Wheatcroft, R. A.; Peck, E. K.; Brophy, L.

    2016-12-01

    Vertical sediment accretion in estuarine salt marshes occurs as sediments settle out of the water column and onto marsh soils during periods of tidal inundation - thus accretion is influenced by both relative sea level rise (RSLR) and sediment flux to the estuary. Oregon estuaries are understudied compared to their East and Gulf Coast counterparts, but provide a unique opportunity to disentangle these effects. A broader study in three Oregon estuaries (Peck et al., this session) indicates RSLR as the dominant factor controlling sedimentation rates. Working in Nehalem Bay (northern Oregon coast), replicate sediment cores were taken along several transects across an elevation gradient for analysis of sediment and carbon accumulation using CT scans, gamma detection of Pb-210, X-Ray Fluorescence (XRF) and Loss-on-Ignition (LOI). Preliminary results indicate sediment accumulation rates over the past century are higher than rates seen in other comparable Oregon salt marshes; this is consistent with past studies and preliminary analysis of remote sensing data that show significant horizontal expansion of Nehalem marshes. A number of possible causes for the high sediment accumulation rates - hydroclimate of Nehalem River, extensive timber harvesting, forest fires such as the so-called Tillamook Burns, and diking of adjacent marshes - are being explored.

  2. Acoustic characteristics of the vowel systems of six regional varieties of American English

    Science.gov (United States)

    Clopper, Cynthia G.; Pisoni, David B.; de Jong, Kenneth

    2012-01-01

    Previous research by speech scientists on the acoustic characteristics of American English vowel systems has typically focused on a single regional variety, despite decades of sociolinguistic research demonstrating the extent of regional phonological variation in the United States. In the present study, acoustic measures of duration and first and second formant frequencies were obtained from five repetitions of 11 different vowels produced by 48 talkers representing both genders and six regional varieties of American English. Results revealed consistent variation due to region of origin, particularly with respect to the production of low vowels and high back vowels. The Northern talkers produced shifted low vowels consistent with the Northern Cities Chain Shift, the Southern talkers produced fronted back vowels consistent with the Southern Vowel Shift, and the New England, Midland, and Western talkers produced the low back vowel merger. These findings indicate that the vowel systems of American English are better characterized in terms of the region of origin of the talkers than in terms of a single set of idealized acoustic-phonetic baselines of “General” American English and provide benchmark data for six regional varieties. PMID:16240825

  3. Modelling renewable energy resource and the electricity network (East Midlands region)

    Energy Technology Data Exchange (ETDEWEB)

    Newton, P.A.; Ma, T.

    2002-07-01

    The UK Government's targets for renewable generation and combined heat and power (CHP) are expected to result in a significant growth in embedded generation. This report describes the results of a study of the capability of the electricity distribution network in the East Midlands to accept embedded generation. Detailed network studies were performed for two sample networks: one representing an urban network (Leicester) and one representing a rural network (Boston). The 132 kV networks of the grid groups covering these areas were also studied. This included an examination of the connection points from major 132 kV busbars at grid supply points down to 11 kV primary substations. Power system studies were performed to identify the constraints and capabilities of the existing network, These studies included load flow to examine voltage profile and overloading, fault level analysis and transient studies to examine generator and network stability following faults on the network and voltage step change due to generator tripping. Space network capacity for the region was identified and used to assess the ability to accommodate regional targets for renewables and CHP. The study also examined constraining factors and potential solutions, including four improvement scenarios.

  4. Geochemical distribution of trace metals and organochlorine contaminants of a lake ontario shoreline marsh

    Energy Technology Data Exchange (ETDEWEB)

    Glooschenko, W A; Capocianco, J; Coburn, J; Glooschenko, V

    1981-02-01

    Rattray Marsh, an 8 ha marsh on the Lake Ontario shoreline at Mississauga, Ontario, is an important local habitat for waterfowl and shorebirds during spring and fall migration. A study was conducted to determine the distribution of nutrients (carbon, nitrogen, and phosphorus) and potential trace metal and organochlorine pollutants in the marsh as evidenced by the sedimentary concentrations of these compounds. Generally, copper, zinc, lead, and mercury were higher in concentration in local soils than in Lake Ontario sediments. Metals and organic carbon levels did not correlate, and the metals appeared to be associated with silts and clays. Organochlorine contaminants include p,p1-DDE, p,p1-DDD, p,p1-DDT, alpha-chlordane, PCB, mirex, and HCB.

  5. Differential impacts of calcium and aluminum treatments on sugar maple and American beech growth dynamics

    Science.gov (United States)

    Joshua M. Halman; Paul G. Schaberg; Gary J. Hawley; Christopher F. Hansen; Timothy J. Fahey

    2015-01-01

    Acid deposition induced losses of calcium (Ca) from northeastern forests have had negative effects on forest health for decades, including the mobilization of potentially phytotoxic aluminum (Al) from soils. To evaluate the impact of changes in Ca and Al availability on sugar maple (Acer saccharum Marsh.) and American beech (Fagus...

  6. Tidal exchange between a freshwater tidal marsh and an impacted estuary: the Scheldt estuary, Belgium

    NARCIS (Netherlands)

    van Damme, S.; Dehairs, F.; Tackx, M.; Beauchard, O.; Struyf, E.; Gribsholt, B.; van Cleemput, O.; Meire, P.

    2009-01-01

    Tidal marsh exchange studies are relatively simple tools to investigate the interaction between tidal marshes and estuaries. They have mostly been confined to only a few elements and to saltwater or brackish systems. This study presents mass-balance results of an integrated one year campaign in a

  7. Modeling tidal freshwater marsh sustainability in the Sacramento-San Joaquin Delta under a broad suite of potential future scenarios

    Science.gov (United States)

    Swanson, Kathleen M.; Drexler, Judith Z.; Fuller, Christopher C.; Schoellhamer, David H.

    2015-01-01

    In this paper, we report on the adaptation and application of a one-dimensional marsh surface elevation model, the Wetland Accretion Rate Model of Ecosystem Resilience (WARMER), to explore the conditions that lead to sustainable tidal freshwater marshes in the Sacramento–San Joaquin Delta. We defined marsh accretion parameters to encapsulate the range of observed values over historic and modern time-scales based on measurements from four marshes in high and low energy fluvial environments as well as possible future trends in sediment supply and mean sea level. A sensitivity analysis of 450 simulations was conducted encompassing a range of eScholarship provides open access, scholarly publishing services to the University of California and delivers a dynamic research platform to scholars worldwide. porosity values, initial elevations, organic and inorganic matter accumulation rates, and sea-level rise rates. For the range of inputs considered, the magnitude of SLR over the next century was the primary driver of marsh surface elevation change. Sediment supply was the secondary control. More than 84% of the scenarios resulted in sustainable marshes with 88 cm of SLR by 2100, but only 32% and 11% of the scenarios resulted in surviving marshes when SLR was increased to 133 cm and 179 cm, respectively. Marshes situated in high-energy zones were marginally more resilient than those in low-energy zones because of their higher inorganic sediment supply. Overall, the results from this modeling exercise suggest that marshes at the upstream reaches of the Delta—where SLR may be attenuated—and high energy marshes along major channels with high inorganic sediment accumulation rates will be more resilient to global SLR in excess of 88 cm over the next century than their downstream and low-energy counterparts. However, considerable uncertainties exist in the projected rates of sea-level rise and sediment avail-ability. In addition, more research is needed to constrain future

  8. Possible causes of poverty within a group of land reform beneficiaries in the midlands of KwaZulu-Natal: Analysis and policy recommendations

    OpenAIRE

    Shinns, L.H.; Lyne, Michael C.

    2005-01-01

    This study investigates possible causes of poverty afflicting a community of land reform beneficiaries in the Midlands of KwaZulu-Natal. The 38 beneficiary households had previously been clustered into four groups displaying different symptoms of poverty. Linear Discriminant Analysis was used first to distinguish households that were relatively income and asset "rich" from those that were relatively income and asset "poor", and second to distinguish households that were relatively income poor...

  9. Surface elevation dynamics in vegetated Spartina marshes versus unvegetated tidal ponds along the mid-Atlantic coast, USA, with implications to waterbirds

    Science.gov (United States)

    Erwin, R. Michael; Cahoon, Donald R.; Prosser, Diann J.; Sanders, Geoffrey; Hensel, Philippe

    2006-01-01

    Mid Atlantic coastal salt marshes contain a matrix of vegetation diversified by tidal pools, pannes, and creeks, providing habitats of varying importance to many species of breeding, migrating, and wintering waterbirds. We hypothesized that changes in marsh elevation were not sufficient to keep pace with those of sea level in both vegetated and unvegetated Spartina alterniflora sites at a number of mid lagoon marsh areas along the Atlantic coast. We also predicted that northern areas would suffer less of a deficit than would southern sites. Beginning in August 1998, we installed surface elevation tables at study sites on Cape Cod, Massachusetts, southern New Jersey, and two locations along Virginia's eastern shore. We compared these elevation changes over the 4-4.5 yr record with the long-term (> 50 yr) tidal records for each locale. We also collected data on waterbird use of these sites during all seasons of the year, based on ground surveys and replicated surveys from observation platforms. Three patterns of marsh elevation change were found. At Nauset Marsh, Cape Cod, the Spartina marsh surface tracked the pond surface, both keeping pace with regional sea-level rise rates. In New Jersey, the ponds are becoming deeper while marsh surface elevation remains unchanged from the initial reading. This may result in a submergence of the marsh in the future, assuming sea-level rise continues at current rates. Ponds at both Virginia sites are filling in, while marsh surface elevation rates do not seem to be keeping pace with local sea-level rise. An additional finding at all sites was that subsidence in the vegetated marsh surfaces was less than in unvegetated areas, reflecting the importance of the root mat in stabilizing sediments. The implications to migratory waterbirds are significant. Submergence of much of the lagoonal marsh area in Virginia and New Jersey over the next century could have major negative (i.e., flooding) effects on nesting populations of marsh

  10. Wind-Driven Sea-Level Variation Influences Dynamics of Salt Marsh Vegation

    DEFF Research Database (Denmark)

    Kim, Daehyun; Cairns, David; Bartholdy, Jesper

    2011-01-01

    Long-term variation of mean sea level has been considered the primary exogenous factor of vegetation dynamics in salt marshes. In this study, we address the importance of short-term, wind-induced rise of the sea surface in such biogeographic changes. There was an unusual opportunity for examining......, waterlogging of marsh soils, which has retarded ecological succession. To conclude, we stress the need for a multitemporal perspective that recognizes the significance of short-term sea-level fluctuations nested within long-term trends......) continuous sedimentation with spatial variability (2.0–4.0 mm yr-1), (3) increased frequency of over-marsh flooding events, and (4) contemporary dominance of Halimione portulacoides, indicating little progressive succession toward a later phase. Conventionally, recent eustatic sea-level rise was believed...... to drive the increased frequency of flooding and such retarded succession. Skallingen, however, has showed more or less equilibrated yearly rates between sea-level rise and surface accretion. This implies that the long-term, gradual sea-level rise alone might not be enough to explain the increased...

  11. Exploring mechanisms of compaction in salt-marsh sediments using Common Era relative sea-level reconstructions

    Science.gov (United States)

    Brain, Matthew J.; Kemp, Andrew C.; Hawkes, Andrea D.; Engelhart, Simon E.; Vane, Christopher H.; Cahill, Niamh; Hill, Troy D.; Donnelly, Jeffrey P.; Horton, Benjamin P.

    2017-07-01

    Salt-marsh sediments provide precise and near-continuous reconstructions of Common Era relative sea level (RSL). However, organic and low-density salt-marsh sediments are prone to compaction processes that cause post-depositional distortion of the stratigraphic column used to reconstruct RSL. We compared two RSL reconstructions from East River Marsh (Connecticut, USA) to assess the contribution of mechanical compression and biodegradation to compaction of salt-marsh sediments and their subsequent influence on RSL reconstructions. The first, existing reconstruction ('trench') was produced from a continuous sequence of basal salt-marsh sediment and is unaffected by compaction. The second, new reconstruction is from a compaction-susceptible core taken at the same location. We highlight that sediment compaction is the only feasible mechanism for explaining the observed differences in RSL reconstructed from the trench and core. Both reconstructions display long-term RSL rise of ∼1 mm/yr, followed by a ∼19th Century acceleration to ∼3 mm/yr. A statistically-significant difference between the records at ∼1100 to 1800 CE could not be explained by a compression-only geotechnical model. We suggest that the warmer and drier conditions of the Medieval Climate Anomaly (MCA) resulted in an increase in sediment compressibility during this time period. We adapted the geotechnical model by reducing the compressive strength of MCA sediments to simulate this softening of sediments. 'Decompaction' of the core reconstruction with this modified model accounted for the difference between the two RSL reconstructions. Our results demonstrate that compression-only geotechnical models may be inadequate for estimating compaction and post-depositional lowering of susceptible organic salt-marsh sediments in some settings. This has important implications for our understanding of the drivers of sea-level change. Further, our results suggest that future climate changes may make salt

  12. Dynamics and fate of SOC in tidal marshes along a salinity gradient (Scheldt estuary, Belgium)

    Science.gov (United States)

    Van de Broek, Marijn; Temmermann, Stijn; Merckx, Roel; Wang, Zhengang; Govers, Gerard

    2016-04-01

    Coastal ecosystems have been attributed the potential to store large amounts of organic carbon (OC), often referred to as blue carbon, of which a considerable amount is stored in tidal marsh soils. Large uncertainties still exist with respect to the amount and controlling factors of soil organic carbon (SOC) stored in these ecosystems. Moreover, most research has focused on SOC dynamics of saltmarshes, while brackish and freshwater marshes are often even more productive and thus receive even larger organic carbon inputs. Therefore, in this study the OC dynamics of tidal marsh soils along an estuarine gradient are studied in order to contribute to our knowledge of 1) the stocks, 2) the controlling factors and 3) the fate of SOC in tidal marshes with different environmental characteristics. This research thus contributes to a better understanding of the potential of coastal environments to store organic carbon under future climatic changes. Soil and vegetation samples are collected in tidal salt-, brackish- and freshwater marshes in the Scheldt estuary (Belgium - The Netherlands). At each tidal marsh, three replicate soil cores up to 1.5m depth in 0.03m increments are collected at locations with both a low and a high elevation. These cores are analyzed for OC, stable C and N isotopes, bulk density and texture. Incubation experiments of topsoil samples were conducted and both aboveground and belowground biomass were collected. The results show that SOC stocks (range: 13,5 - 35,4 kg OC m-2), standing biomass (range: 2000 - 7930 g DW m-2) and potential soil respiration of CO2 (range: 0,03 - 0,12 % per unit OC per day) decrease with increasing salinity. This shows that both the amount of OC from local macrophytes and the quality of the organic matter are important factors controlling the SOC stocks. In addition, based on the analysis of stable C and N isotopes, it appears that when a significant fraction of SOC is derived from local macrophytes, higher SOC stocks are

  13. Environmental extremes and biotic interactions facilitate depredation of endangered California Ridgway’s rail in a San Francisco Bay tidal marsh

    Science.gov (United States)

    Overton, Cory T.; Bobzien, Steven; Grefsrud, Marcia

    2016-01-01

    On 23 December 2015 while performing a high tide population survey for endangered Ridgway’s rails (Rallus obsoletus obsoletus; formerly known as the California clapper rail) and other rail species at Arrowhead Marsh, Martin Luther King Jr. Regional Shoreline, Oakland, California, the authors observed a series of species interactions resulting in the predation of a Ridgway’s rail by an adult female peregrine falcon (Falco peregrinus). High tide surveys are performed during the highest tides of the year when tidal marsh vegetation at Arrowhead Marsh becomes inundated, concentrating the tidal marsh obligate species into the limited area of emergent vegetation remaining as refuge cover. Annual mean tide level (elevation referenced relative to mean lower low water) at Arrowhead Marsh is 1.10 m, mean higher high water is 2.04 m (NOAA National Ocean Service 2014) and the average elevation of the marsh surface is 1.60 m (Overton et al. 2014). Tidal conditions on the day of the survey were predicted to be 2.42 m. Observed tides at the nearby Alameda Island tide gauge were 8 cm higher than predicted due to a regional low-pressure system and warmer than average sea surface temperatures (NOAA National Ocean Service 2014). The approximately 80 cm deep inundation of the marsh plain was sufficient to completely submerge tidal marsh vegetation and effectively remove 90% of refugia habitats.

  14. Short term changes in hydroperiod after thin layer sediment placement on a New Jersey salt marsh and implications for design

    Science.gov (United States)

    Piercy, C.; Carrillo, C. C.; VanZomeren, C. M.; Berkowitz, J.; Chasten, M. A.; Golden, D.; Jahn, J.; Welp, T. L.; Yepsen, M.

    2017-12-01

    Over the winter of 2015-2016, the U.S. Army Corps of Engineers Philadelphia District partnered with New Jersey Department of Environmental Protection, The Nature Conservancy, Green Trust Alliance, Green Vest, and Princeton Hydro to implement a wetland thin layer placement on a salt marsh to the west of Avalon, New Jersey using dredged sediments removed from the Federal navigation channel in response to impacts from Hurricane Sandy. Prior to sediment placement, the marsh exhibited signs of degradation, including fragmentation of the marsh plain. The marsh is characterized by large, open water areas ( 1 m deep) fringed with overhanging banks and punctuated by small remnant ( 1-5 m) islands of intact marsh. The objective of the placement effort was to increase the elevation of degraded marsh areas to a level commensurate with the growth of low marsh vegetation dominated by Spartina alterniflora Loisel and to provide a small ( 5-15 cm) elevation boost to vegetated marsh areas surrounding the open water pools. We examine changes in inundation and tidal exchange resulting from the thin layer placement immediately after placement and a year later. Changes in sediment grain size and other factors are also considered. Coupling hydrologic measurements with observed vegetation recovery, we identify target elevations and sediment depths relative to mean sea level and mean high water consistent with rapid recovery in initially vegetated and open water areas.

  15. The Stalled Recovery of the Iraqi Marshes

    Directory of Open Access Journals (Sweden)

    Richard H. Becker

    2014-01-01

    Full Text Available The Iraqi (Mesopotamian Marshes, an extensive wetlands system in Iraq, has been heavily impacted by both human and climate forces over the past decades. In the period leading up to the Second Gulf War in 2002, the marshlands were shrinking due to both a policy of draining and water diversion in Iraq and construction of dams upstream on the Tigris and Euphrates rivers. Following the war through 2006, this trend was reversed as the diversions were removed and active draining stopped. A combination of MODIS and GRACE datasets were used to determine the change in surface water area (SWA in the marshes, marshland extent and change in mass both upriver in the Tigris and Euphrates watersheds and in the marshlands. Results suggest that the post war dam removal and decreased pumping in 2003 provided only temporary respite for the marshlands (2003–2006 SWA: 1,477 km2 increase (600%, water equivalent depth (WED: +2.0 cm/yr.; 2006–2009: −860 km2 (−41% WED: −3.9 cm/yr.. Unlike in the period 2003–2006, from 2006 forward the mass variations in the marshes are highly correlated with those in the upper and middle watershed (R = 0.86 and 0.92 respectively, suggesting that any recovery due to that removal is complete, and that all future changes are tied more strongly to any climate changes that will affect recharge in the upper Tigris-Euphrates system. Precipitation changes in the watershed show a reduction of an average of 15% below the 15 yr mean in 2007–2011 This corresponds with published ensemble predictions for the 2071–2099 time period, that suggested similar marshland shrinkage should be expected in that time period.

  16. Nitrogen removal through N cycling from sediments in a constructed coastal marsh as assessed by 15N-isotope dilution.

    Science.gov (United States)

    Ro, Hee-Myong; Kim, Pan-Gun; Park, Ji-Suk; Yun, Seok-In; Han, Junho

    2018-04-01

    Constructed coastal marsh regulates land-born nitrogen (N) loadings through salinity-dependent microbial N transformation processes. A hypothesis that salinity predominantly controls N removal in marsh was tested through incubation in a closed system with added- 15 NH 4 + using sediments collected from five sub-marshes in Shihwa marsh, Korea. Time-course patterns of concentrations and 15 N-atom% of soil-N pools were analyzed. Sediments having higher salinity and lower soil organic-C and acid-extractable organic-N exhibited slower rates of N mineralization and immobilization, nitrification, and denitrification. Rates of denitrification were not predicted well by sediment salinity but by its organic-C, indicating heterotrophic denitrification. Denitrification dominated N-loss from this marsh, and nitrogen removal capacity of this marsh was estimated at 337 kg N day -1 (9.9% of the daily N-loadings) considering the current rooting depth of common reeds (1.0 m). We showed that sediment N removal decreases with increasing salinity and can increase with increasing organic-C for heterotrophic denitrification. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Mercury Cycling in Salt Marsh Pond Ecosystems: Cape Cod, MA

    Science.gov (United States)

    Ganguli, P. M.; Gonneea, M. E.; Lamborg, C. H.; Kroeger, K. D.; Swarr, G.; Vadman, K. J.; Baldwin, S.; Brooks, T. W.; Green, A.

    2014-12-01

    We are measuring total mercury (HgT) and monomethylmercury (CH3Hg+ or MMHg) in pore water, surface water, and sediment cores from two salt marsh pond systems on the south shore of Cape Cod, MA to characterize the distribution of mercury species and to identify features that influence mercury speciation and transport. Sage Lot Pond is relatively undisturbed and has low nitrogen loading (12 kg ha-1 y-1). It is part of the Waquoit Bay National Estuarine Reserve and is surrounded by undeveloped wooded uplands. In contrast, Great Pond is highly impacted. Nitrogen loading to the site is elevated (600 kg ha-1 y-1) and the marsh is adjacent to a large residential area. In both systems, a 1 to 2 m organic-rich peat layer overlies the permeable sand aquifer. Groundwater in this region is typically oxic, where pore water within salt marsh peat is suboxic to anoxic. We hypothesize that redox gradients at the transition from the root zone to peat and at the peat-sand interface may provide habitat for MMHg-producing anaerobic bacteria. Preliminary results from a 2-m nearshore depth profile at Sage Lot Pond indicate HgT in groundwater within the sand aquifer occurred primarily in the > 0.2 μm fraction, with unfiltered concentrations exceeding 100 pM. Filtered (fraction of filtered HgT in peat pore water. Although MMHg in both groundwater and pore water remained around 1 pM throughout our depth profile, we observed an increase in sediment MMHg (0.3 to 1.6 μg/kg) at the peat-sand interface. MMHg comprised ~50% of the HgT concentration in pore water suggesting mercury in the salt marsh peat is biologically available.

  18. No evidence for memory interference across sessions in food hoarding marsh tits Poecile palustris under laboratory conditions.

    Science.gov (United States)

    Urhan, A Utku; Brodin, Anders

    2015-05-01

    Scatter hoarding birds are known for their accurate spatial memory. In a previous experiment, we tested the retrieval accuracy in marsh tits in a typical laboratory set-up for this species. We also tested the performance of humans in this experimental set-up. Somewhat unexpectedly, humans performed much better than marsh tits. In the first five attempts, humans relocated almost 90 % of the caches they had hidden 5 h earlier. Marsh tits only relocated 25 % in the first five attempts and just above 40 % in the first ten attempts. Typically, in this type of experiment, the birds will be caching and retrieving many times in the same sites in the same experimental room. This is very different from the conditions in nature where hoarding parids only cache once in a caching site. Hence, it is possible that memories from previous sessions will disturb the formation of new memories. If there is such proactive interference, the prediction is that success should decay over sessions. Here, we have designed an experiment to investigate whether there is such memory interference in this type of experiment. We allowed marsh tits and humans to cache and retrieve in three repeated sessions without prior experience of the arena. The performance did not change over sessions, and on average, marsh tits correctly visited around 25 % of the caches in the first five attempts. The corresponding success in humans was constant across sessions, and it was around 90 % on average. We conclude that the somewhat poor performance of the marsh tits did not depend on proactive memory interference. We also discuss other possible reasons for why marsh tits in general do not perform better in laboratory experiments.

  19. Emerson Parcel of Dutch Slough Tidal Marsh Restoration Project

    Science.gov (United States)

    Information about the SFBWQP Emerson Parcel of Dutch Slough Tidal Marsh Restoration Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  20. Mapping changing distributions of dominant species in oil-contaminated salt marshes of Louisiana using imaging spectroscopy

    Science.gov (United States)

    Beland, Michael; Roberts, Dar A.; Peterson, Seth H.; Biggs, Trent W.; Kokaly, Raymond F.; Piazza, Sarai; Roth, Keely L.; Khanna, Shruti; Ustin, Susan L.

    2016-01-01

    The April 2010 Deepwater Horizon (DWH) oil spill was the largest coastal spill in U.S. history. Monitoring subsequent change in marsh plant community distributions is critical to assess ecosystem impacts and to establish future coastal management priorities. Strategically deployed airborne imaging spectrometers, like the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), offer the spectral and spatial resolution needed to differentiate plant species. However, obtaining satisfactory and consistent classification accuracies over time is a major challenge, particularly in dynamic intertidal landscapes.Here, we develop and evaluate an image classification system for a time series of AVIRIS data for mapping dominant species in a heavily oiled salt marsh ecosystem. Using field-referenced image endmembers and canonical discriminant analysis (CDA), we classified 21 AVIRIS images acquired during the fall of 2010, 2011 and 2012. Classification results were evaluated using ground surveys that were conducted contemporaneously to AVIRIS collection dates. We analyzed changes in dominant species cover from 2010 to 2012 for oiled and non-oiled shorelines.CDA discriminated dominant species with a high level of accuracy (overall accuracy = 82%, kappa = 0.78) and consistency over three imaging dates (overall2010 = 82%, overall2011 = 82%, overall2012 = 88%). Marshes dominated by Spartina alterniflora were the most spatially abundant in shoreline zones (≤ 28 m from shore) for all three dates (2010 = 79%, 2011 = 61%, 2012 = 63%), followed by Juncus roemerianus (2010 = 11%, 2011 = 19%, 2012 = 17%) and Distichlis spicata (2010 = 4%, 2011 = 10%, 2012 = 7%).Marshes that were heavily contaminated with oil exhibited variable responses from 2010 to 2012. Marsh vegetation classes converted to a subtidal, open water class along oiled and non-oiled shorelines that were similarly situated in the landscape. However, marsh loss along oil-contaminated shorelines

  1. Using Imaging Spectroscopy to Map Changing Distributions of Dominant Species in Oil-Contaminated Salt Marshes of Louisiana

    Science.gov (United States)

    Beland, M. C.; Roberts, D. A.; Peterson, S.; Biggs, T. W.; Kokaly, R. F.; Piazza, S.; Roth, K. L.; Khanna, S.; Ustin, S.

    2016-12-01

    The April 2010 Deepwater Horizon (DWH) oil spill was the largest coastal spill in U.S. history. Monitoring subsequent change in marsh plant community distributions is critical to assess ecosystem impacts and to establish future coastal management priorities. Strategically deployed airborne imaging spectrometers, like the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS), offer the spectral and spatial resolution needed to differentiate plant species. However, obtaining satisfactory and consistent classification accuracies over time is a major challenge, particularly in dynamic intertidal landscapes. Here, we develop and evaluate an image classification system for a time series of AVIRIS data for mapping dominant species in a heavily oiled salt marsh ecosystem. Using field-referenced image endmembers and canonical discriminant analysis (CDA), we classified 21 AVIRIS images acquired during the fall of 2010, 2011 and 2012. Classification results were evaluated using ground surveys that were conducted contemporaneously to AVIRIS collection dates. We analyzed changes in dominant species cover from 2010-2012 for oiled and non-oiled shorelines. CDA discriminated dominant species with a high level of accuracy (overall accuracy = 82%, kappa = 0.78) and consistency over three imaging dates (overall2010 = 82%, overall2011 = 82%, overall2012 = 88%). Marshes dominated by Spartina alterniflora were the most spatially abundant in shoreline zones (≤ 28m from shore) for all three dates (2010 = 79%, 2011 = 61%, 2012 = 63%), followed by Juncus roemerianus (2010 = 11%, 2011 = 19%, 2012 = 17%) and Distichlis spicata (2010 = 4%, 2011 = 10%, 2012 = 7%). Marshes that were heavily contaminated with oil exhibited variable responses from 2010-2012. Marsh vegetation classes converted to a subtidal, open water class along oiled and non-oiled shorelines that were similarly situated in the landscape. However, marsh loss along oil-contaminated shorelines doubled that of non

  2. Climate-related variation in plant peak biomass and growth phenology across Pacific Northwest tidal marshes

    Science.gov (United States)

    Buffington, Kevin J.; Dugger, Bruce D.; Thorne, Karen M.

    2018-03-01

    The interannual variability of tidal marsh plant phenology is largely unknown and may have important ecological consequences. Marsh plants are critical to the biogeomorphic feedback processes that build estuarine soils, maintain marsh elevation relative to sea level, and sequester carbon. We calculated Tasseled Cap Greenness, a metric of plant biomass, using remotely sensed data available in the Landsat archive to assess how recent climate variation has affected biomass production and plant phenology across three maritime tidal marshes in the Pacific Northwest of the United States. First, we used clipped vegetation plots at one of our sites to confirm that tasseled cap greenness provided a useful measure of aboveground biomass (r2 = 0.72). We then used multiple measures of biomass each growing season over 20-25 years per study site and developed models to test how peak biomass and the date of peak biomass varied with 94 climate and sea-level metrics using generalized linear models and Akaike Information Criterion (AIC) model selection. Peak biomass was positively related to total annual precipitation, while the best predictor for date of peak biomass was average growing season temperature, with the peak 7.2 days earlier per degree C. Our study provides insight into how plants in maritime tidal marshes respond to interannual climate variation and demonstrates the utility of time-series remote sensing data to assess ecological responses to climate stressors.

  3. Sedimentological and radiochemical characteristics of marsh deposits from Assateague Island and the adjacent vicinity, Maryland and Virginia, following Hurricane Sandy

    Science.gov (United States)

    Smith, Christopher G.; Marot, Marci E.; Ellis, Alisha M.; Wheaton, Cathryn J.; Bernier, Julie C.; Adams, C. Scott

    2015-09-15

    The effect of tropical and extratropical cyclones on coastal wetlands and marshes is highly variable and depends on a number of climatic, geologic, and physical variables. The impacts of storms can be either positive or negative with respect to the wetland and marsh ecosystems. Small to moderate amounts of inorganic sediment added to the marsh surface during storms or other events help to abate pressure from sea-level rise. However, if the volume of sediment is large and the resulting deposits are thick, the organic substrate may compact causing submergence and a loss in elevation. Similarly, thick deposits of coarse inorganic sediment may also alter the hydrology of the site and impede vegetative processes. Alternative impacts associated with storms include shoreline erosion at the marsh edge as well as potential emergence. Evaluating the outcome of these various responses and potential long-term implications is possible from a systematic assessment of both historical and recent event deposits. A study was conducted by the U.S. Geological Survey to assess the sedimentological and radiochemical characteristics of marsh deposits from Assateague Island and areas around Chincoteague Bay, Maryland and Virginia, following Hurricane Sandy in 2012. The objectives of this study were to (1) characterize the surficial sediment of the relict to recent washover fans and back-barrier marshes in the study area, and (2) characterize the sediment of six marsh cores from the back-barrier marshes and a single marsh island core near the mainland. These geologic data will be integrated with other remote sensing data collected along Assateague Island in Maryland and Virginia and assimilated into an assessment of coastal wetland response to storms.

  4. Soil preparation methods promoting ectomycorrhizal colonization and American chestnut Castanea dentata establishment in coal mine restoration

    Science.gov (United States)

    Jenise M. Bauman; Carolyn H. Keiffer; Shiv Hiremath; Brian C. McCarthy

    2013-01-01

    The objective of this research was to evaluate soil subsurface methods that may aid in seedling establishment and encourage root colonization from a diverse group of ectomycorrhizal (ECM) fungi during restoration projects. American chestnut Castanea dentata Marsh. Borkh. and backcrossed chestnuts seedlings were planted on a reclaimed coal mine site...

  5. A chronology of hurricane landfalls at Little Sippewissett Marsh, Massachusetts, USA, using optical dating

    Science.gov (United States)

    Madsen, A. T.; Duller, G. A. T.; Donnelly, J. P.; Roberts, H. M.; Wintle, A. G.

    2009-08-01

    Optical dating has been applied to sediments preserved in Little Sippewissett Marsh, Massachusetts, USA, which are associated with overwashing of the beach barrier during hurricane strikes on the coast. The aims were to determine the hurricane landfall frequency, and make comparisons with independent age control and the historical record. Written sources of hurricane activity along the American east coast are only considered reliable back to the mid 19th century, but the sedimentary record is potentially much longer. Optical dating was applied to quartz grains extracted from thirteen samples within a sediment core from the salt-marsh. Variability in the luminescence characteristics between aliquots was observed and ~ 33% of the measured aliquots were discarded based upon the ratio of the fast component to the medium component. The majority of the samples gave normal dose distributions implying homogeneous resetting of the luminescence signal at the time of deposition, but three of the samples required application of the minimum age model (MAM). Ages ranging between 20 ± 2 and 594 ± 38 years were obtained and are broadly in agreement with independent chronologies, thus demonstrating the potential of optical dating in this setting. The hurricane record based upon optical dating extends approximately 300 years further back in time than the official National Oceanic Atmospheric Administration (NOAA) record. The localised nature of hurricane landfalls means that it will be necessary to collect multiple cores from a number of different sites in order to build up a complete hurricane record for this part of the coast.

  6. The Future of Suisun Marsh as Mitigation Habitat

    Directory of Open Access Journals (Sweden)

    Peter B. Moyle

    2013-10-01

    Full Text Available Suisun Marsh is the largest tidal wetland in the San Francisco Estuary that has been subject to 6000 years of constant change, which is accelerating. Decisions made today will have maajor effects on its value as habitat for native biota in the future

  7. A Qualitative Study of the Impact of the London 2012 Olympics on Families in the East Midlands of England: Lessons for Sports Development Policy and Practice

    Science.gov (United States)

    Mackintosh, Chris; Darko, Natalie; Rutherford, Zoe; Wilkins, Hetty-May

    2015-01-01

    The dynamics and culture of families are central to individual and community sport and physical activity participation. This research project examined the lived experiences and day-to-day realities of the London 2012 Olympics from the perspectives of five families in the East Midlands region of England. The aims of the project were to assess the…

  8. Wetland Loss Patterns and Inundation-Productivity Relationships Prognosticate Widespread Salt Marsh Loss for Southern New England

    Science.gov (United States)

    Tidal salt marsh is a key defense against, yet is especially vulnerable to, the effects of accelerated sea level rise. To determine whether salt marshes in southern New England will be stable given increasing inundation over the coming decades, we examined current loss patterns, ...

  9. Consequences of climate change, eutrophication, and other anthropogenic impacts to coastal salt marshes: multiple stressors reduce resiliency and sustainability

    Science.gov (United States)

    Watson, E. B.; Wigand, C.; Nelson, J.; Davey, E.; Van Dyke, E.; Wasson, K.

    2011-12-01

    Coastal salt marshes provide a wide variety of ecosystem services, including habitat for protected vertebrates and ecologically valuable invertebrate fauna, flood protection, and improvements in water quality for adjacent marine and estuarine environments. Here, we consider the impacts of future sea level rise combined with other anthropogenic stressors to salt marsh sustainability through the implementation of field and laboratory mesocosms, manipulative experiments, correlative studies, and predictive modeling conducted in central California and southern New England salt marshes. We report on measurements of soil respiration, decomposition, sediment accumulation, and marsh elevation, which considered jointly suggest an association between nitrate input and marsh elevation loss resulting from mineralization of soil organic matter. Furthermore, use of imaging techniques (CT scans) has shown differences in belowground root and rhizome structure associated with fertilization, resulting in a loss of sediment cohesion promoted by fine root structure. Additionally, field and greenhouse mesocosm experiments have provided insight into the specific biogeochemical processes responsible for plant mortality at high immersion or salinity levels. In conclusion, we have found that poor water quality (i.e. eutrophication) leads to enhanced respiration and decomposition of soil organic matter, which ultimately contributes to a loss of salt marsh sustainability. However, marsh deterioration studied at field sites (Jamaica Bay, NY and Elkhorn Slough, CA) is associated not only with enhanced nutrient loads, but also increased immersion due to tidal range increases resulting from dredging. To ensure the continuation of the ecosystem services provided by tidal wetlands and to develop sustainable management strategies that provide favorable outcomes under a variety of future sea level rise and land use scenarios, we need to develop a better understanding of the relative impacts of the

  10. Long-Term Surveys Show Invasive Overbite Clams (Potamocorbula amurensis are Spatially Limited in Suisun Marsh, California

    Directory of Open Access Journals (Sweden)

    Jason Baumsteiger

    2017-07-01

    Full Text Available https://doi.org/10.15447/sfews.2017v15iss2art6The overbite clam (Potamocorbula amurensis is a major invasive species in the San Francisco Estuary, California, and has been implicated in the decline of pelagic productivity and native fish species. Little is known of its impact on Suisun Marsh, a large brackish tidal region of the estuary. We looked at the abundance and spatial distribution of clams in the marsh, including examining the influence of water quality, using long-term (1988–2015 otter trawl surveys. Temporal trends indicated that overbite clam abundance has been increasing, but adult clams were spatially restricted to a single large slough (Suisun. Clams were absent from most interior channels, limiting their overall effect on the marsh aquatic ecosystem. Abiotic variables, particularly salinity, proved important predictors of overbite clam abundance, although the variables examined alone could not explain overbite clam distributions. We propose that connectivity, detritus loads, and/or predation pressure may work in conjunction with abiotic variables to cause poor survival rates for recruits in interior marsh sites, keeping the distribution limited. Overall results are encouraging for restoration projects in brackish tidal marshes that need to deal with overbite clams.

  11. Copper and lead levels in crops and soils of the Holland Marsh Area-Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Czuba, M.; Hutchinson, T.C.

    1980-01-01

    A study was made of the occurrence, distribution, and concentrations of the heavy metals copper (Cu) and lead (Pb) in the soils and crops of the important horticultural area north of Toronto known as the Holland Marsh. The soils are deep organic mucks (> 85% organic matter), derived by the drainage of black marshland soils, which has been carried out over the past 40 years. A comparison is made between the Pb and Cu concentrations in undrained, uncultivated areas of the marsh and in the intensively used horticultural area. Analyses show a marked accumulation of Cu in surface layers of cultivated soils, with a mean surface concentration of 130 ppM, declining to 20 ppM at a 32-cm depth. Undrained (virgin) soils of the same marshes had < 20 ppM at all depths. Lead concentrations also declined through the profile, from concentrations of 22 to 10 ppM. In comparison, undrained areas had elevated Pb levels. Cultivation appeared to have increased Cu, but lowered Pb in the marsh. Copper and lead levels found in the crops were generally higher in the young spring vegetables than in the mature fall ones. Leafy crops, especially lettuce (Lactuca L.) and celery (Apium graveolens), accumulated higher Pb levels in their foliage compared with levels in root crops. Cultivation procedures, including past pesticide applications and fertilizer additions, appeared to be principal sources of Cu. Mobility from the soil and into the plant for these elements in the marsh muck soils is discussed.

  12. Winter climate change and coastal wetland foundation species: salt marshes vs. mangrove forests in the southeastern United States.

    Science.gov (United States)

    Osland, Michael J; Enwright, Nicholas; Day, Richard H; Doyle, Thomas W

    2013-05-01

    We live in an era of unprecedented ecological change in which ecologists and natural resource managers are increasingly challenged to anticipate and prepare for the ecological effects of future global change. In this study, we investigated the potential effect of winter climate change upon salt marsh and mangrove forest foundation species in the southeastern United States. Our research addresses the following three questions: (1) What is the relationship between winter climate and the presence and abundance of mangrove forests relative to salt marshes; (2) How vulnerable are salt marshes to winter climate change-induced mangrove forest range expansion; and (3) What is the potential future distribution and relative abundance of mangrove forests under alternative winter climate change scenarios? We developed simple winter climate-based models to predict mangrove forest distribution and relative abundance using observed winter temperature data (1970-2000) and mangrove forest and salt marsh habitat data. Our results identify winter climate thresholds for salt marsh-mangrove forest interactions and highlight coastal areas in the southeastern United States (e.g., Texas, Louisiana, and parts of Florida) where relatively small changes in the intensity and frequency of extreme winter events could cause relatively dramatic landscape-scale ecosystem structural and functional change in the form of poleward mangrove forest migration and salt marsh displacement. The ecological implications of these marsh-to-mangrove forest conversions are poorly understood, but would likely include changes for associated fish and wildlife populations and for the supply of some ecosystem goods and services. © 2012 Blackwell Publishing Ltd.

  13. Impact and Recovery Pattern of a Spring Fire on a Pacific Coast Marsh - Observations and Implications for Endangered Species

    Science.gov (United States)

    Brown, L. N.; Willis, K. S.; Ambrose, R. F.; MacDonald, G. M.

    2015-12-01

    The flammability of California coastal marsh vegetation is highest in winter and spring when dominant high marsh plants such as Sarcocornia pacifica are dormant. With climate change the number of cool-season fires are increasing in the state, and marsh systems are becoming more vulnerable to fire disturbance. Very little information exists in peer-reviewed or grey literature on the presence of fire in Pacific Coast tidal marshes. In 1993, the Green Meadows fire in Ventura County, California burned a small portion of tidally influenced Sarcocornia­-dominated marsh at Point Mugu. After the May 2013 Springs Fire burned a similar portion of the salt marsh vegetation, we conducted a two-year vegetation recovery survey using transects of surface vegetation plots and MODIS derived NDVI remote sensing monitoring. Recovery during the first year was limited. Sixteen months into the recovery period, percent plant coverage reached an average of approximately 60% for all plots in the burned area, as opposed to an average of 100% in control plots, and remained at that level for the duration of the study. NDVI did not approach near pre-fire conditions until 19 months after the fire. While recovery may have been influenced by California's current extreme drought conditions, the recurrence of fire and rate of recovery raise many important questions as to the role of fire in Pacific coast tidal marshes. For example, the lack of Salicornia cover over more than an entire breeding season would be detrimental to protected species such as Rallus obsoletus. Fire adds new vulnerabilities on critical tidal marsh habitat already taxed by the threat of sea-level rise, coastal squeeze and invasive species.

  14. Restoration of Tidal Flow to Impounded Salt Marsh Exerts Mixed Effect on Leaf Litter Decomposition

    Science.gov (United States)

    Henry, B. A.; Schade, J. D.; Foreman, K.

    2015-12-01

    Salt marsh impoundments (e.g. roads, levees) disconnect marshes from ocean tides, which impairs ecosystem services and often promotes invasive species. Numerous restoration projects now focus on removing impoundments. Leaf litter decomposition is a central process in salt marsh carbon and nutrient cycles, and this study investigated the extent to which marsh restoration alters litter decomposition rates. We considered three environmental factors that can potentially change during restoration: salinity, tidal regime, and dominant plant species. A one-month field experiment (Cape Cod, MA) measured decay of litter bags in impounded, restored, and natural marshes under ambient conditions. A two-week lab experiment measured litter decay in controlled incubations under experimental treatments for salinity (1ppt and 30 ppt), tidal regime (inundated and 12 hr wet-dry cycles), and plant species (native Spartina alterniflora and invasive Phragmites australis). S. alterniflora decomposed faster in situ than P. australis (14±1.0% mass loss versus 0.74±0.69%). Corroborating this difference in decomposition, S. alterniflora supported greater microbial respiration during lab incubation, measured as CO2 flux from leaf litter and biological oxygen demand of water containing leached organic matter (OM). However, nutrient analysis of plant tissue and leached OM show P. australis released more nitrogen than S. alterniflora. Low salinity treatments in both lab and field experiments decayed more rapidly than high salinity treatments, suggesting that salinity inhibited microbial activity. Manipulation of inundation regime did not affect decomposition. These findings suggest the reintroduction of tidal flow to an impounded salt marsh can have mixed effects; recolonization by the native cordgrass could supply labile OM to sediment and slow carbon sequestration, while an increase in salinity might inhibit decomposition and accelerate sequestration.

  15. Determining the Contribution of Non-Carbonate Alkalinity from Intertidal Salt Marshes to Coastal Buffering Capacity

    Science.gov (United States)

    Anderson, L. B.; Gonneea, M. E.; Wang, A. Z.; Chu, S. N.

    2016-02-01

    Coastal ocean acidification varies with high magnitude and frequency due to both natural and anthropogenic factors, and levels of acidity in coastal waters have important consequences for environmental concerns such as local settlement of bivalve populations. Therefore, it is useful to fully evaluate measurements that increase understanding of coastal ocean acidification dynamics. This study focuses on the quantification and characterization of alkalinity, the ability of a specific water parcel to buffer against inputs of acidity. There has been limited research on the magnitude and composition of non-carbonate alkalinity (NCA) generated in coastal environments. Specifically, this study evaluates the contribution of NCA to total alkalinity (TA) in an intertidal salt marsh, assesses NCA dynamics within the marsh, and begins to determine composition of NCA. We demonstrated that it was possible to develop a CO2-free full titration system modeled after Cai et al. (1998) that produced reasonable values for TA and NCA. From initial use of this system, it was evident that NCA was a significant contributor to TA within the Sage Lot Pond salt marsh, and that NCA was dominated by organic/unknown alkalinity. Preliminary observations indicated that NCA variability in the marsh was directly proportional to water flux entering the tidal creek from Sage Lot Pond. The source of higher NCA concentrations in Sage Lot Pond was unknown, but may have been due to organic/unknown alkalinity generated in a different part of the marsh and exported to our specific tidal creek site. Preliminary assessment of NCA composition indicates an acid/base species with a pK value of 6.46. From evaluation of NCA magnitude and relation to water flux, it is reasonable to conclude that NCA generated within salt marshes may be a significant source of buffering capacity to the coastal ocean.

  16. Nests of Marsh harrier (Circus aeruginosus L. as refuges of potentially phytopathogenic and zoopathogenic fungi

    Directory of Open Access Journals (Sweden)

    Teresa Kornillowicz-Kowalska

    2018-01-01

    Full Text Available Birds’ nests may be refuges for various species of fungi including that which are potentially phytopathogenic and zoopathogenic. Among the 2449 isolates of fungi obtained from nests of Marsh harriers 96.8% belonged to filamentous fungi. In total, 37 genera were identified from 63 fungi species. Within the mycobiotas of the examined nests populations of fungi which are potentially pathogenic for humans, homoiothermous animals and plants dominated. Among 63 species, 46 (72% were potentially pathogenic fungi of which 18 species were potentially phytopathogenic and 32 species were pathogenic for homoiothermous animals. Inter alia species of fungi were found in the Marsh harriers nests: Aspergillus fumigatus, Aspergillus flavus, Scopulariopsis brevicaulis, Chrysosporium keratinophilum and Fusarium poae, Fusarium sporotrichioides. In terms of numbers, dominant in Marsh harrier nests were fungi pathogenic to birds, other homoiothermous animals and humans. On that basis it was concluded that Marsh harrier nests are both a source of fungal infections for that species and one of the links in the epidemiological cycle of opportunistic fungi for humans.

  17. Nests of Marsh harrier (Circus aeruginosus L.) as refuges of potentially phytopathogenic and zoopathogenic fungi.

    Science.gov (United States)

    Kornillowicz-Kowalska, Teresa; Kitowski, Ignacy

    2018-01-01

    Birds' nests may be refuges for various species of fungi including that which are potentially phytopathogenic and zoopathogenic. Among the 2449 isolates of fungi obtained from nests of Marsh harriers 96.8% belonged to filamentous fungi. In total, 37 genera were identified from 63 fungi species. Within the mycobiotas of the examined nests populations of fungi which are potentially pathogenic for humans, homoiothermous animals and plants dominated. Among 63 species, 46 (72%) were potentially pathogenic fungi of which 18 species were potentially phytopathogenic and 32 species were pathogenic for homoiothermous animals. Inter alia species of fungi were found in the Marsh harriers nests: Aspergillus fumigatus , Aspergillus flavus , Scopulariopsis brevicaulis , Chrysosporium keratinophilum and Fusarium poae , Fusarium sporotrichioides . In terms of numbers, dominant in Marsh harrier nests were fungi pathogenic to birds, other homoiothermous animals and humans. On that basis it was concluded that Marsh harrier nests are both a source of fungal infections for that species and one of the links in the epidemiological cycle of opportunistic fungi for humans.

  18. Vegetation death and rapid loss of surface elevation in two contrasting Mississippi delta salt marshes: The role of sedimentation, autocompaction and sea-level rise

    Science.gov (United States)

    Day, J.W.; Kemp, G.P.; Reed, D.J.; Cahoon, D.R.; Boumans, R.M.; Suhayda, J.M.; Gambrell, R.

    2011-01-01

    From 1990 to 2004, we carried out a study on accretionary dynamics and wetland loss in salt marshes surrounding two small ponds in the Mississippi delta; Old Oyster Bayou (OB), a sediment-rich area near the mouth of the Atchafalaya River and Bayou Chitigue (BC), a sediment-poor area about 70. km to the east. The OB site was stable, while most of the marsh at BC disappeared within a few years. Measurements were made of short-term sedimentation, vertical accretion, change in marsh surface elevation, pond wave activity, and marsh soil characteristics. The OB marsh was about 10. cm higher than BC; the extremes of the elevation range for Spartina alterniflora in Louisiana. Vertical accretion and short-term sedimentation were about twice as high at BC than at OB, but the OB marsh captured nearly all sediments deposited, while the BC marsh captured <30%. The OB and BC sites flooded about 15% and 85% of the time, respectively. Marsh loss at BC was not due to wave erosion. The mineral content of deposited sediments was higher at OB. Exposure and desiccation of the marsh surface at OB increased the efficiency that deposited sediments were incorporated into the marsh soil, and displaced the marsh surface upward by biological processes like root growth, while also reducing shallow compaction. Once vegetation dies, there is a loss of soil volume due to loss of root turgor and oxidation of root organic matter, which leads to elevation collapse. Revegetation cannot occur because of the low elevation and weak soil strength. The changes in elevation at both marsh sites are punctuated, occurring in steps that can either increase or decrease elevation. When a marsh is low as at BC, a step down can result in an irreversible change. At this point, the option is not restoration but creating a new marsh with massive sediment input either from the river or via dredging. ?? 2010 Elsevier B.V.

  19. Chance findings about early holocene tidal marshes of Grays Harbor, Washington, in relation to rapidly rising seas and great subduction earthquakes

    Science.gov (United States)

    Phipps, James B.; Hemphill-Haley, Eileen; Atwater, Brian F.

    2015-06-18

    Tidal marshes commonly build upward apace with gradual rise in the level of the sea. It is expected, however, that few tidal marshes will keep up with accelerated sea-level rise later in this century. Tidal marshes have been drowned, moreover, after subsiding during earthquakes.

  20. Effects of livestock species and stocking density on accretion rates in grazed salt marshes

    Science.gov (United States)

    Nolte, Stefanie; Esselink, Peter; Bakker, Jan P.; Smit, Christian

    2015-01-01

    Coastal ecosystems, such as salt marshes, are threatened by accelerated sea-level rise (SLR). Salt marshes deliver valuable ecosystem services such as coastal protection and the provision of habitat for a unique flora and fauna. Whether salt marshes in the Wadden Sea area are able to survive accelerated SLR depends on sufficient deposition of sediments which add to vertical marsh accretion. Accretion rate is influenced by a number of factors, and livestock grazing was recently included. Livestock grazing is assumed to reduce accretion rates in two ways: (a) directly by increasing soil compaction through trampling, and (b) indirectly by affecting the vegetation structure, which may lower the sediment deposition. For four years, we studied the impact of two livestock species (horse and cattle) at two stocking densities (0.5 and 1.0 animal ha-1) on accretion in a large-scale grazing experiment using sedimentation plates. We found lower cumulative accretion rates in high stocking densities, probably because more animals cause more compaction and create a lower canopy. Furthermore, a trend towards lower accretion rates in horse-compared to cattle-grazed treatments was found, most likely because (1) horses are more active and thus cause more compaction, and (2) herbage intake by horses is higher than by cattle, which causes a higher biomass removal and shorter canopy. During summer periods, negative accretion rates were found. When the grazing and non-grazing seasons were separated, the impact of grazing differed among years. In summer, we only found an effect of different treatments if soil moisture (precipitation) was relatively low. In winter, a sufficiently high inundation frequency was necessary to create differences between grazing treatments. We conclude that stocking densities, and to a certain extent also livestock species, affect accretion rates in salt marshes. Both stocking densities and livestock species should thus be taken into account in management

  1. Ecosystem metabolism in a temporary Mediterranean marsh (Donana National Park, SW Spain)

    DEFF Research Database (Denmark)

    Geertz-Hansen, O.; Montes, C.; Duarte, C.M.

    2011-01-01

    metabolic balance of the open waters supporting submerged macrophytes of the Donana marsh (SW Spain) was investigated in spring, when community production is highest. The marsh community (benthic + pelagic) was net autotrophic with net community production rates averaging 0.61 g C m(-2) d(-1......), and gross production rates exceeding community respiration rates by, on average, 43%. Net community production increased greatly with increasing irradiance, with the threshold irradiance for communities to become net autotrophic ranging from 42 to 255 mu E m(-2) s(-1), with net heterotrophic at lower...

  2. Distribution and metabolism of quaternary amines in salt marshes

    Science.gov (United States)

    King, Gary M.

    1985-01-01

    Quaternary amines such as glycine betaine (GBT) are common osmotically active solutes in much of the marine biota. GBT is accumulated by various bacteria, algae, higher plants, invertebrates, and vertebrates in response to salinity or water stresses; in some species, GBT occurs at tens to hundreds of millimolar concentrations and can account for a significant fraction of total nitrogen. Initial studies suggest that GBT is readily converted to two potential methane precursors, trimethylamine (TMA) and acetate, in anoxic sediments. TMA is apparently the most important methane precursor in surface sediments containing sulfate reducing bacteria. In salt marshes, the bulk of the methane formed may be due to the metabolism of TMA rather than other substrates. Current research is focussed on testing this hypothesis and on determining the role of quaternary amino osmoregulatory solutes in methane fluxes from marine environments. Preliminary studies have dealt with several problems: (1) determination of GBT concentrations in the dominant flora and fauna of salt marshes; (2) synthesis of radiolabelled GBT for metabolic studies; and (3) determination of fates of BGT in marine sediments using radiotracers. Both GC and HPLC techniques have been used to assay GBT concentrations in plant and animal tissues. S. alterniflora is probably the only significant source of GBT (and indirectly of methane) since the biomass and distribution of most other species is limited. Current estimates suggest that S. alterniflora GBT could account for most of the methane efflux from salt marshes.

  3. Primary production of edaphic algal communities in a Mississippi salt marsh

    International Nuclear Information System (INIS)

    Sullivan, M.J.; Moncreiff, C.A.

    1988-01-01

    Primary production rates of edaphic algae associated with the sediments beneath four monospecific canopies of vascular plants were determined over an annual cycle in a Mississippi salt marsh. The edaphic algal flora was dominated by small, motile pennate diatoms. Algal production (as measured by 14 C uptake) was generally highest in spring-early summer and lowest in fall. Hourly rates ranged from a low of 1.4 mg C/m 2 in Juncus roemerianus Scheele to a high of 163 mg C/m 2 beneath the Scirpus olneyi Gray canopy. Stepwise multiple regressions identified a soil moisture index and chlorophyll a as the best environmental predictors of hourly production; light energy reaching the marsh surface and sediment and air temperature proved of little value. Adding the relative abundances of 33 diatom taxa to the set of independent variables only slightly increased R 2 ; however, virtually all variables selected were diatom taxa. R 2 was only 0.38 for the Spartina alterniflora Loisel. habitat but ranged from 0.70 to 0.87 for the remaining three vascular plant zones. Annual rates of algal production (g C/m 2 ) were estimated as follows: Juncus (28), Spartina (57), Distichlis spicata (L.) Greene (88), and Scirpus (151). The ratio of annual edaphic algal production to vascular plant net aerial production (EAP/VPP) was 10-12% for the first three habitats and 61% for Scirpus. Chlorophyll a concentrations, annual algal production rates, and EAP/VPP values were comparable to those determined in Texas, Delaware, and Massachusetts salt marshes but lower than those reported for Georgia and particularly California marshes

  4. A New Approach to Monitoring Coastal Marshes for Persistent Flooding

    Science.gov (United States)

    Kalcic, M. T.; Undersood, Lauren W.; Fletcher, Rose

    2012-01-01

    Many areas in coastal Louisiana are below sea level and protected from flooding by a system of natural and man-made levees. Flooding is common when the levees are overtopped by storm surge or rising rivers. Many levees in this region are further stressed by erosion and subsidence. The floodwaters can become constricted by levees and trapped, causing prolonged inundation. Vegetative communities in coastal regions, from fresh swamp forest to saline marsh, can be negatively affected by inundation and changes in salinity. As saltwater persists, it can have a toxic effect upon marsh vegetation causing die off and conversion to open water types, destroying valuable species habitats. The length of time the water persists and the average annual salinity are important variables in modeling habitat switching (cover type change). Marsh type habitat switching affects fish, shellfish, and wildlife inhabitants, and can affect the regional ecosystem and economy. There are numerous restoration and revitalization projects underway in the coastal region, and their effects on the entire ecosystem need to be understood. For these reasons, monitoring persistent saltwater intrusion and inundation is important. For this study, persistent flooding in Louisiana coastal marshes was mapped using MODIS (Moderate Resolution Imaging Spectroradiometer) time series of a Normalized Difference Water Index (NDWI). The time series data were derived for 2000 through 2009, including flooding due to Hurricane Rita in 2005 and Hurricane Ike in 2008. Using the NDWI, duration and extent of flooding can be inferred. The Time Series Product Tool (TSPT), developed at NASA SSC, is a suite of software developed in MATLAB(R) that enables improved-quality time series images to be computed using advanced temporal processing techniques. This software has been used to compute time series for monitoring temporal changes in environmental phenomena, (e.g. NDVI times series from MODIS), and was modified and used to

  5. The evaluation of cutoff rigidities and reentrant albedo calculations for Palestine, Dallas, and Midland, Texas

    International Nuclear Information System (INIS)

    Shea, M.A.; Smart, D.F.

    1975-01-01

    By using the trajectory-tracing technique, cutoff rigidities for Palestine, Dallas, and Midland, Texas, have been calculated as a function of various zenith and azimuth angles. Extensive analysis of the trajectory calculations shows that there is a systematic uncertainty involved in computing the lowest allowed rigidity, and this uncertainty may be a significant fraction of the penumbral width. Continuation of the trajectory-tracing process below the Stormer cutoff allows an evaluation of the reentrant albedo, showing that the average invariant latitude of the guiding center of the trajectory at the albedo origin is the same as the average invariant latitude of the guiding center of the particle trajectory at the detection point. No significant difference in the cutoff rigidities for these locations is found when the external magnetic fields present in the magnetosphere are added to the geomagnetic field of internal origin

  6. Effects of Tide Stage on the Use of Salt Marshes by Wading Birds in Rhode Island

    Science.gov (United States)

    To determine how tide stage affects wading bird abundance, behavior, and foraging in three Narragansett Bay salt marshes (RI), we conducted surveys at 10-min intervals—across the full tidal range—during six days at each marsh in July/September of 2006. The wading bird community ...

  7. Nitrogen processing in a tidal freshwater marsh: a whole ecosystem 15N labeling study

    DEFF Research Database (Denmark)

    Gribsholt, B.; Boschker, H.T.S.; Struyf, E.

    2005-01-01

    We quantified the fate and transport of watershed-derived ammonium in a tidal freshwater marsh fringing the nutrient-rich Scheldt River in a whole-ecosystem 15N labeling experiment. 15N-NH4+ was added to the floodwater entering a 3,477 m2 tidal marsh area, and marsh ammonium processing...... and retention were traced in six subsequent tide cycles. We present data for the water phase components of the marsh system, in which changes in concentration and isotopic enrichment of NO3-, NO2- , N2O, N2, NH4+, and suspended particulate nitrogen (SPN) were measured in concert with a mass balance study....... Simultaneous addition of a conservative tracer (NaBr) confirmed that tracer was evenly distributed, and the Br2 budget was almost closed (115% recovery). All analyzed dissolved and suspended N pools were labeled, and 31% of added 15N-NH4+ was retained or transformed. Nitrate was the most important pool for 15N...

  8. Interpreter's Guide to Blackbird Marsh Nature Trail.

    Science.gov (United States)

    Environmental Studies Center, Pensacola, FL.

    This booklet was prepared to help the user interpret the natural history of Blackbird Marsh Nature Trail in Escambia County, Florida, and serves as a guide to the animal and plant life. The publication is part of a series of illustrated guides designed for use by teachers and students of all levels in conjunction with field trips to the 1200-acre…

  9. Environmental conditions in the Namskaket Marsh Area, Orleans, Massachusetts: A summary of studies by the U.S. Geological Survey, 1989–2011

    Science.gov (United States)

    Weiskel, Peter K.; Barbaro, Jeffrey R.; DeSimone, Leslie A.

    2016-09-23

    Namskaket Marsh and its tidal creek system are potential receptors for a treated wastewater plume originating from a septage treatment facility in the northwest part of Orleans, Massachusetts, on Cape Cod. From 1989 to 2011, the U.S. Geological Survey, in cooperation with State and local partners, conducted a series of studies in the Namskaket Marsh area to characterize the potential effects of the plume on the marsh and its tidal creek system. Studies included characterizing the baseline vegetation and salinity distribution in the marsh, monitoring the movement of the wastewater plume downgradient of the septage treatment facility, and sampling nutrient concentrations in the tidal creek system during a baseline period prior to the arrival of the plume at the marsh boundary. The Inner Namskaket Marsh baseline vegetation survey in 1995 found it to be dominated by Phragmites australis (common reed, 44 percent of vegetative cover), Spartina patens (salt marsh hay, 17 percent), and Spartina alterniflora (cordgrass, 9 percent). Phragmites occurrence was correlated with shallow pore-water salinity in the marsh peat and was largely confined to areas with salinities less than 4 parts per thousand. Baseline, ebb-tide nutrient concentrations at the tidal creek sampling stations during 1994–96 showed strong seasonal variations for ammonium, likely associated with the seasonal cycle of growth and senescence for the dominant salt marsh grasses (S. alterniflora and S. patens). The seasonal cycle for nitrate was generally less pronounced.

  10. Safety evaluation report related to the operation of Midland Plant, Units 1 and 2. Docket Nos. 50-329 and 50-330. Consumers Power Company

    International Nuclear Information System (INIS)

    1982-06-01

    This report supplements the Safety Evaluation Report, NUREG-0793, issued with respect to the application filed for licenses to operate the Midland Plant, Units 1 and 2 (Docket Nos. 50-329 and 50-330). This supplement provides recent information regarding resolution of some of the open items identified in the Safety Evaluation Report and discusses recommendations of the Advisory Committee on Reactor Safeguards in its interim report dated June 8, 1982

  11. Cycling of oxyanion-forming trace elements in groundwaters from a freshwater deltaic marsh

    Science.gov (United States)

    Telfeyan, Katherine; Breaux, Alexander; Kim, Jihyuk; Kolker, Alexander S.; Cable, Jaye E.; Johannesson, Karen H.

    2018-05-01

    Pore waters and surface waters were collected from a freshwater system in southeastern Louisiana to investigate the geochemical cycling of oxyanion-forming trace elements (i.e., Mo, W, As, V). A small bayou (Bayou Fortier) receives input from a connecting lake (Lac des Allemands) and groundwater input at the head approximately 5 km directly south of the Mississippi River. Marsh groundwaters exchange with bayou surface water but are otherwise relatively isolated from outside hydrologic forcings, such as tides, storms, and effects from local navigation canals. Rather, redox processes in the marsh groundwaters appear to drive changes in trace element concentrations. Elevated dissolved S(-II) concentrations in marsh groundwaters suggest greater reducing conditions in the late fall and winter as compared to the spring and late summer. The data suggest that reducing conditions in marsh groundwaters initiate the dissolution of Fe(III)/Mn(IV) oxide/hydroxide minerals, which releases adsorbed and/or co-precipitated trace elements into solution. Once in solution, the fate of these elements is determined by complexation with aqueous species and precipitation with iron sulfide minerals. The trace elements remain soluble in the presence of Fe(III)- and SO42-- reducing conditions, suggesting that either kinetic limitations or complexation with aqueous ligands obfuscates the correlation between V and Mo sequestration in sediments with reducing or euxinic conditions.

  12. Effects of causeway construction on vegetation and sedimentation in North Carolina tidal marshes

    Science.gov (United States)

    Knowlton, A.; Leonard, L.; Pricope, N. G.; Eulie, D.

    2017-12-01

    Causeways, especially those constructed to facilitate transportation across low lying tidal marshes, are known to affect tidal exchanges and thereby potentially influence geological and biological processes in these ecosystems. While these impacts have been documented in several expansive marsh systems with large tidal ranges, the extent of these impacts in smaller tidal creek watersheds is less understood. This study examined how the presence, absence, and removal of small causeways affected sedimentological processes and vegetation characteristics in two small tidal creek watersheds in Wilmington, NC. Surficial deposition rates, determined using petri-dish sediment traps, indicate that mean deposition landward of a small causeway (1.64 mg cm-2day-1) is significantly lower (pchanges adjacent to the causeway. Partial causeway removal in one of these systems in 2006 also provided the opportunity to evaluate how the marsh canopy responded to causeway removal. Using Juncus roemerianus and Spartina alterniflora as a proxy for changes in tidal exchange, spectroradiometer data and aerial imagery available in 2006 and 2016 will be used to quantify changes in canopy coverage subsequent to causeway removal. Although this study is ongoing, the preliminary results indicate that small causeways, similar to their larger counterparts, significantly affect the rate and characteristics of sediment delivered to landward marshes and also affect tidal exchanges that lead to changes in vegetation characteristics.

  13. Five new species of the genera Heerz Marsh, Lissopsius Marsh and Ondigus Braet, Barbalho and van Achterberg (Braconidae, Doryctinae) from the Chamela-Cuixmala biosphere reserve in Jalisco, Mexico

    Science.gov (United States)

    Zaldívar-Riverón, Alejandro; Martínez, Juan José; Ceccarelli, Fadia Sara; Shaw, Scott R.

    2012-01-01

    Abstract Five new species belonging to the poorly known Neotropical doryctine parasitoid wasps genera Heerz Marsh (Heerz ecmahla sp. n. and Heerz macrophthalma sp. n.), Lissopsius Marsh (Lissopsius pacificus sp. n. and Lissopsius jalisciensis sp. n.) and Ondigus Braet, Barbalho & van Achterberg (Ondigus cuixmalensis sp. n.) are described from the Chamela-Cuixmala Biosphere reserve in Jalisco, Mexico. Keys to the described species of the above three genera are provided. The phylogenetic placement of the examined taxa is investigated based on mitochondrial (COI) and nuclear (28S, 2nd and 3rd domain regions) DNA sequence data. PMID:22328849

  14. The significance of spatial and temporal patterns of algal mat deposition in structuring salt-marsh vegetation

    NARCIS (Netherlands)

    Van Soelen, J.; Herman, P.M.J.; Bouma, T.J.

    2006-01-01

    Question: Are there hot spots of algal mat deposition in space and time at the marsh scale and, if so, how does this affect the coexistence of a dominant (Spartina anglica) and gap dependent (Salicornia europaea) species? Location: The Rattekaai salt marsh in the Scheldt estuary in the southwestern

  15. Climate-related variation in plant peak biomass and growth phenology across Pacific Northwest tidal marshes

    Science.gov (United States)

    Buffington, Kevin J.; Dugger, Bruce D.; Thorne, Karen M.

    2018-01-01

    The interannual variability of tidal marsh plant phenology is largely unknown and may have important ecological consequences. Marsh plants are critical to the biogeomorphic feedback processes that build estuarine soils, maintain marsh elevation relative to sea level, and sequester carbon. We calculated Tasseled Cap Greenness, a metric of plant biomass, using remotely sensed data available in the Landsat archive to assess how recent climate variation has affected biomass production and plant phenology across three maritime tidal marshes in the Pacific Northwest of the United States. First, we used clipped vegetation plots at one of our sites to confirm that tasseled cap greenness provided a useful measure of aboveground biomass (r2 = 0.72). We then used multiple measures of biomass each growing season over 20–25 years per study site and developed models to test how peak biomass and the date of peak biomass varied with 94 climate and sea-level metrics using generalized linear models and Akaike Information Criterion (AIC) model selection. Peak biomass was positively related to total annual precipitation, while the best predictor for date of peak biomass was average growing season temperature, with the peak 7.2 days earlier per degree C. Our study provides insight into how plants in maritime tidal marshes respond to interannual climate variation and demonstrates the utility of time-series remote sensing data to assess ecological responses to climate stressors.

  16. Meiobenthos of Saphala salt marsh, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Ansari, Z.A.; Parulekar, A.H.

    Benthic fauna of the salt marsh comprised 10 taxonomic groups, dominated by nematodes (63.9%), harpacticoids (18.5%), turbellaria (5.6%), crustacean nauplii (5.4%) and polychaetes (4.1%). The population density varied from 282 to 17300 (10 cm)-2...

  17. The influence of neap-spring tidal variation and wave energy on sediment flux in salt marsh tidal creeks

    Science.gov (United States)

    Lacy, Jessica; Ferner, Matthew C.; Callaway, John C.

    2018-01-01

    Sediment flux in marsh tidal creeks is commonly used to gage sediment supply to marshes. We conducted a field investigation of temporal variability in sediment flux in tidal creeks in the accreting tidal marsh at China Camp State Park adjacent to northern San Francisco Bay. Suspended-sediment concentration (SSC), velocity, and depth were measured near the mouths of two tidal creeks during three six-to-ten-week deployments: two in winter and one in summer. Currents, wave properties and SSC were measured in the adjacent shallows. All deployments spanned the largest spring tides of the season. Results show that tidally-averaged suspended-sediment flux (SSF) in the tidal creeks decreased with increasing tidal energy, and SSF was negative (bayward) for tidal cycles with maximum water surface elevation above the marsh plain. Export during the largest spring tides dominated the cumulative SSF measured during the deployments. During ebb tides following the highest tides, velocities exceeded 1 m/s in the narrow tidal creeks, resulting in negative tidally-averaged water flux, and mobilizing sediment from the creek banks or bed. Storm surge also produced negative SSF. Tidally-averaged SSF was positive in wavey conditions with moderate tides. Spring-tide sediment export was about 50% less at a station 130 m further up the tidal creek than at the creek mouth. The negative tidally-averaged water flux near the creek mouth during spring tides indicates that in the lower marsh, some of the water flooding directly across the bay--marsh interface drains through the tidal creeks, and suggests that this interface may be a pathway for sediment supply to the lower marsh as well.

  18. Salt Marsh Monitoring in Jamaica Bay, New York from 2003 to 2013: A Decade of Change from Restoration to Hurricane Sandy

    Directory of Open Access Journals (Sweden)

    Anthony Campbell

    2017-02-01

    Full Text Available This study used Quickbird-2 and Worldview-2, high resolution satellite imagery, in a multi-temporal salt marsh mapping and change analysis of Jamaica Bay, New York. An object-based image analysis methodology was employed. The study seeks to understand both natural and anthropogenic changes caused by Hurricane Sandy and salt marsh restoration, respectively. The objectives of this study were to: (1 document salt marsh change in Jamaica Bay from 2003 to 2013; (2 determine the impact of Hurricane Sandy on salt marshes within Jamaica Bay; (3 evaluate this long term monitoring methodology; and (4 evaluate the use of multiple sensor derived classifications to conduct change analysis. The study determined changes from 2003 to 2008, 2008 to 2012 and 2012 to 2013 to better understand the impact of restoration and natural disturbances. The study found that 21 ha of salt marsh vegetation was lost from 2003 to 2013. From 2012 to 2013, restoration efforts resulted in an increase of 10.6 ha of salt marsh. Hurricane Sandy breached West Pond, a freshwater environment, causing 3.1 ha of freshwater wetland loss. The natural salt marsh showed a decreasing trend in loss. Larger salt marshes in 2012 tended to add vegetation in 2012–2013 (F4,6 = 13.93, p = 0.0357 and R2 = 0.90. The study provides important information for the resource management of Jamaica Bay.

  19. Windows of opportunity for salt marsh vegetation establishment on bare tidal flats : The importance of temporal and spatial variability in hydrodynamic forcing

    NARCIS (Netherlands)

    Hu, Z.; Van Belzen, J.; Van der Wal, D.; Balke, T.; Wang, Z.B.; Stive, M.J.F.; Bouma, T.J.

    2015-01-01

    Understanding the mechanisms limiting and facilitating salt marsh vegetation initial establishment is of widespread importance due to the many valuable services salt marsh ecosystems offer. Salt marsh dynamics have been investigated by many previous studies, but the mechanisms that enable or disable

  20. The history of metals pollution in Narragansett Bay as recorded by salt-marsh sediments

    International Nuclear Information System (INIS)

    Bricker, S.B.

    1990-01-01

    Sediment cores from 5 salt marshes from the head to the mouth of Narragansett Bay and an additional core from a lagoon on Block Island Sound were analyzed for 210 Pb and for Fe, Mn, Cu, Pb, Cr, Zn, Ag, and Ni in order to examine the long-term variation of metal inputs to Narragansett Bay. The 210 Pb results were used to determine accretion rates for each core. Distributions of Fe and Mn were used as indicators of chemical conditions of sediment cores and Cu, Pb, Cr, Zn, Ag, and Ni distributions with time were compared with known or estimated source inputs to examine the long-term variation of pollutant metal inputs to Narragansett Bay. At one location, duplicate cores were sampled to look at variability within a marsh. At another location, a high marsh, receiving predominantly atmospheric inputs and a low marsh, receiving waterborne and atmospheric inputs, were sampled so that atmospheric and tidal contributions could be determined. A comparison was made of the distributions of metals in bay cores and in the lagoon core. All the Rhode Island marshes accrete at rates equal to or greater than the local rise in sea level. Based on the 210 Pb chronologies, pollutant metals began to increase in the mid to late 1800s, corresponding to coal burning emissions to the atmosphere. Steeper increases in the 1900s reflect industrial and sewage discharges. Maximum concentrations were reached in the 1950s and have declined almost continuously since then. Observed reductions were attributable to implementation of and improvements to sewage treatment, and controls on atmospheric emissions

  1. Bioremediation efficacy in Marrow Marsh following the Apex oil spill, Galveston Bay, Texas

    International Nuclear Information System (INIS)

    Nadeau, R.; Singhvi, R.; Ryabik, J.; Lin, Yihua; Syslo, J.

    1992-01-01

    Samples taken from Marrow Marsh in Galveston Bay, Texas were taken to assess the efficacy of the August 5, 1990 bioremediation treatment in the marsh following the Apex barges oil spill on July 28, 1990. The bioremediation treatment combined a lyophilized bacterial mixture and a nutrient mix containing phosphorus and nitrogen. Samples from the marsh had been collected over a 96 h period from both treated and untreated oiled sites. Oil fingerprinting, fatty acid analysis, polynuclear aromatic hydrocarbons analysis, and total petroleum hydrocarbons analysis were performed to evaluate changes in the chemical characteristics of spilled oil. Results of analyses, although not statistically reliable, failed to support the occurrence of any definite chemical alteration in the spilled oil that could be attributed to the bioremediation treatment. The relatively short sampling period and the number of samples taken, however, may have been insufficient to document the efficacy of the overall bioremediation effect. 13 refs., 6 figs., 4 tabs

  2. Great Lakes clams find refuge from zebra mussels in restored, lake-connected marsh (Ohio)

    Science.gov (United States)

    Nichols, S. Jerrine; Wilcox, Douglas A.

    2004-01-01

    Since the early 1990s, more than 95 percent of the freshwater clams once found in Lake Erie have died due to the exotic zebara mussel (Dreissena polymorpha). Zebra mussels attach themselves to native clams in large numbers, impeding the ability of the clams to eat and burrow. However, in 1996, we discovered a population of native clams in Metzger Marsh in western Lake Erie (about 50 miles [80 km] east of Toledo) that were thriving despite the longtime presence of zebra mussel in surrounding waters. At that time, Metzger Marsh was undergoing extensive restoration, including construction of a dike to replace the eroded barrier beach and of a water-control structure to maintain hydrologic connections with the lake (Wilcox and Whillans 1999). The restoration plan called for a drawdown of water levels to promote plant growth from the seedbank -- a process that would also destroy most of the clam population. State and federal resource managers recommended removing as many clams as possible to a site that was isolated from zebra mussels, and then returning them to the marsh after it was restored. We removed about 7,000 native clams in 1996 and moved them back to Metzger Marsh in 1999.

  3. Grazing management can counteract the impacts of climate change-induced sea level rise on salt marsh-dependent waterbirds

    DEFF Research Database (Denmark)

    Clausen, Kevin Kuhlmann; Stjernholm, Michael; Clausen, Preben

    2013-01-01

    with these changes. In addition, we quantify the areal extent of inadequate salt marsh management in four EU Special Protection Areas for Birds, and demonstrate concurrent population dynamics in four species relying on managed habitats. We conclude by investigating potential compensation for climate change......1) Climate change–induced rises in sea level threaten to drastically reduce the areal extent of important salt marsh habitats for large numbers of waterfowl and waders. Furthermore, recent changes in management practice have rendered existent salt marshes unfavourable to many birds, as lack...... (around 1 cow per hectare) is an important initiative to counteract the accelerating climate change–induced habitat loss in near-coastal areas across the globe, and to secure priority salt marsh habitats that support internationally important populations of breeding, wintering and staging waterfowl...

  4. Year-one recovery of an intermediate marsh in south Louisiana after an in-situ burn for oil spill remediation. Volume 1

    International Nuclear Information System (INIS)

    Baustian, J.J.; Mendelssohn, I.A.; Lin, Q.; Rapp, J.; Myers, J.

    2007-01-01

    This study examined the recovery of an intermediate marsh in south Louisiana following an oil spill caused by a storage tank that ruptured during Hurricane Katrina. In situ burning of the oil spill was shown to be a successful form of cleanup that did not cause extensive physical damage to the marsh. The burn plan and execution of the burn was described, with particular focus on vegetation recovery in 28 recovery plots. Plots were monitored for aboveground biomass, plant height and stem density. The study showed that when done properly, in-situ burning eliminates oil from the marsh while combusting the oiled aboveground vegetation, leaving the belowground portions of the plant unharmed. Burns performed with as little as 2 cm of water on the marsh surface can buffer the root zone from the burn and increase plant survival. In this study, the structural and functional attributes of burned areas that were heavily and moderately oil were compared to 2 unburned and unoiled reference marshes. Within 9 months of the in situ burn, the above ground vegetation in the marsh had completely recovered. The burn adequately removed the oiled vegetation and allowed for the natural regrowth of the marsh vegetation. 27 refs., 2 tabs., 2 figs

  5. Modeling wave attenuation by salt marshes in Jamaica Bay, New York, using a new rapid wave model

    Science.gov (United States)

    Marsooli, Reza; Orton, Philip M.; Mellor, George

    2017-07-01

    Using a new rapid-computation wave model, improved and validated in the present study, we quantify the value of salt marshes in Jamaica Bay—a highly urbanized estuary located in New York City—as natural buffers against storm waves. We augment the MDO phase-averaged wave model by incorporating a vegetation-drag-induced energy dissipation term into its wave energy balance equation. We adopt an empirical formula from literature to determine the vegetation drag coefficient as a function of environmental conditions. Model evaluation using data from laboratory-scale experiments show that the improved MDO model accurately captures wave height attenuation due to submerged and emergent vegetation. We apply the validated model to Jamaica Bay to quantify the influence of coastal-scale salt marshes on storm waves. It is found that the impact of marsh islands is largest for storms with lower flood levels, due to wave breaking on the marsh island substrate. However, the role of the actual marsh plants, Spartina alterniflora, grows larger for storms with higher flood levels, when wave breaking does not occur and the vegetative drag becomes the main source of energy dissipation. For the latter case, seasonality of marsh height is important; at its maximum height in early fall, S. alterniflora causes twice the reduction as when it is at a shorter height in early summer. The model results also indicate that the vegetation drag coefficient varies 1 order of magnitude in the study area, and suggest exercising extra caution in using a constant drag coefficient in coastal wetlands.

  6. Does Avicennia germinans expansion alter salt marsh nitrogen removal capacity?

    Science.gov (United States)

    Tatariw, C.; Kleinhuizen, A.; Rajan, S.; Flournoy, N.; Sobecky, P.; Mortazavi, B.

    2017-12-01

    Plant species expansion poses risks to ecosystem services through alterations to plant-microbiome interactions associated with changes to key microbial drivers such as organic carbon (C) substrates, nitrogen (N) availability, and rhizosphere-associated microbial communities. In the northern Gulf of Mexico (GOM), warming winter temperatures associated with climate change have promoted Avicennia germinans (black mangrove) expansion into salt marshes. To date, there is limited knowledge regarding the effects of mangrove expansion on vital ecosystem services such as N cycling in the northern GOM. We designed a field-based study to determine the potential effects of mangrove expansion on salt marsh N biogeochemical cycling in the Spartina alterniflora dominated Chandeleur Islands (LA, USA). We used a combination of process rate measurements and metadata to: 1) Determine the impact of mangrove expansion on salt marsh denitrification and dissimilatory nitrate reduction to ammonium (DNRA), with the goal of quantifying losses or gains in ecosystem services; and 2) identify the mechanisms driving changes in ecosystem services to improve predictions about the impacts of mangrove expansion on salt marsh functional resiliency. The pneumatophore root structure of A. germinans is efficient at delivering oxygen (O2) to sediment, which can promote coupled nitrification-denitrification and decrease sulfide inhibition. We hypothesized that increased sediment O2, when coupled with cooler soil temperatures caused by plant shading, will favor denitrification instead of the DNRA process. An increase in sediment O2, as well as higher N content of A. germinans litter, will also result in a shift in the microbial community. Initial findings indicated that the denitrification pathway dominates over DNRA regardless of vegetation type, with average denitrification rates of 30.1 µmol N kg-1 h-1 versus average DNRA rates of 8.5 µmol N kg-1 h-1. However, neither denitrification nor DNRA rates

  7. Effects of prescribed burning on marsh-elevation change and the risk of wetland loss

    Science.gov (United States)

    McKee, Karen L.; Grace, James B.

    2012-01-01

    Marsh-elevation change is the net effect of biophysical processes controlling inputs versus losses of soil volume. In many marshes, accumulation of organic matter is an important contributor to soil volume and vertical land building. In this study, we examined how prescribed burning, a common marsh-management practice, may affect elevation dynamics in the McFaddin National Wildlife Refuge, Texas by altering organic-matter accumulation. Experimental plots were established in a brackish marsh dominated by Spartina patens, a grass found throughout the Gulf of Mexico and Atlantic marshes. Experimental plots were subjected to burning and nutrient-addition treatments and monitored for 3.5 years (April 2005 – November 2008). Half of the plots were burned once in 2006; half of the plots were fertilized seasonally with nitrogen, phosphorus, and potassium. Before and after the burns, seasonal measurements were made of soil physicochemistry, vegetation structure, standing and fallen plant biomass, aboveground and belowground production, decomposition, and accretion and elevation change (measured with Surface Elevation Tables (SET)). Movements in different soil strata (surface, root zone, subroot zone) were evaluated to identify which processes were contributing to elevation change. Because several hurricanes occurred during the study period, we also assessed how these storms affected elevation change rates. The main findings of this study were as follows: 1. The main drivers of elevation change were accretion on the marsh surface and subsurface movement below the root zone, but the relative influence of these processes varied temporally. Prior to Hurricanes Gustav and Ike (September 2008), the main driver was subsurface movement; after the hurricane, both accretion and subsurface movement were important. 2. Prior to Hurricanes Gustav and Ike, rates of elevation gain and accretion above a marker horizon were higher in burned plots compared to nonburned plots, whereas

  8. Methane emissions from a freshwater marsh in response to experimentally simulated global warming and nitrogen enrichment

    DEFF Research Database (Denmark)

    Flury, Sabine; McGinnis, Daniel Frank; Gessner, Mark O.

    2010-01-01

    We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel ...... to the atmosphere, even when they occupy only relatively small littoral areas. More detailed investigations are clearly needed to assess whether global warming and nitrogen deposition can have climate feedbacks by altering methane fluxes from these wetlands.  ......We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel...... traps deployed in a series of enclosures for two 3 week periods. Diffusive fluxes were estimated on the basis of measured CH4 concentrations and application of Fick's law. Neither diffusive nor ebullitive fluxes of methane were significantly affected by warming or nitrate enrichment, possibly because...

  9. New England salt marsh recovery: opportunistic colonization of an invasive species and its non-consumptive effects.

    Directory of Open Access Journals (Sweden)

    Tyler C Coverdale

    Full Text Available Predator depletion on Cape Cod (USA has released the herbivorous crab Sesarmareticulatum from predator control leading to the loss of cordgrass from salt marsh creek banks. After more than three decades of die-off, cordgrass is recovering at heavily damaged sites coincident with the invasion of green crabs (Carcinusmaenas into intertidal Sesarma burrows. We hypothesized that Carcinus is dependent on Sesarma burrows for refuge from physical and biotic stress in the salt marsh intertidal and reduces Sesarma functional density and herbivory through consumptive and non-consumptive effects, mediated by both visual and olfactory cues. Our results reveal that in the intertidal zone of New England salt marshes, Carcinus are burrow dependent, Carcinus reduce Sesarma functional density and herbivory in die-off areas and Sesarma exhibit a generic avoidance response to large, predatory crustaceans. These results support recent suggestions that invasive Carcinus are playing a role in the recovery of New England salt marshes and assertions that invasive species can play positive roles outside of their native ranges.

  10. Ability of salt marsh plants for TBT remediation in sediments

    OpenAIRE

    Carvalho, P. N.; Basto, M. C.; Moreira da Silva, M.; Machado, A.; Bordalo, A.; Vasconcelos, M. T.

    2010-01-01

    The capability of Halimione portulacoides, Spartina maritima, and Sarcocornia fruticosa (halophytes very commonly found in salt marshes from Mediterranean areas) for enhancing remediation of tributyltin (TBT) from estuarine sediments was investigated, using different experimental conditions.

  11. Development of a Climate Change Adaptation Strategy for Management of Coastal Marsh Systems in Southern New England USA

    Science.gov (United States)

    Sea level rise is accelerating throughout the U.S. Northeast causing shoreline erosion, increased coastal flooding, and marsh vulnerability to the impact of storms. Coastal marshes provide flood abatement, carbon and nutrient sequestration, water quality maintenance, and habitat ...

  12. Development of a Climate-Change Adaptation Strategy for Management of Coastal Marsh Systems in Southern New England USA

    Science.gov (United States)

    Sea level rise is accelerating throughout the U.S. Northeast causing shoreline erosion, increased coastal flooding, and marsh vulnerability to the impact of storms. Coastal marshes provide flood abatement, carbon and nutrient sequestration, water quality maintenance, and habitat ...

  13. Vegetation change in a man-made salt marsh affected by a reduction in both grazing and drainage

    NARCIS (Netherlands)

    Esselink, Peter; Fresco, LFM; Dijkema, KS

    In order to restore natural salt marsh in a 460-ha nature reserve established in man-made salt marsh in the Dollard estuary, The Netherlands, the artificial drainage system was neglected and cattle grazing reduced. Vegetation changes were traced through two vegetation surveys and monitoring of

  14. Salt-marsh erosion associated with hurricane landfall in southern New England in the fifteenth and seventeenth centuries

    NARCIS (Netherlands)

    Plassche, Orson van de; Erkens, Gilles; Vliet, Frank van; Brandsma, J.; Borg, K. van der; Jong, A.F.M. de

    2006-01-01

    Lithostratigraphic and radiocarbon data from the inland section of Pattagansett River Marsh, Connecticut, show that this sheltered part of the salt marsh underwent significant erosion twice during the past 600 yr, each time followed by rapid and complete infilling of the eroded space with tidal mud

  15. Dynamics of methane emissions from a freshwater marsh of northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wenyan; Song, Changchun; Zhang, Jinbo [Northeast Institute of Geography and Agroecology, Chinese Academic Science, Changchun Jilin, 130012 (China)

    2006-12-01

    In this paper, CH{sub 4} flux was measured from Nov. 2002 to Oct. 2005, to estimate CH{sub 4} emissions in winter and during freeze-thaw period, and interannual variation in CH{sub 4} emissions in freshwater marsh in northeast China. The results showed that there was an obvious CH{sub 4} emission (0.1-2.3 mg m{sup -2} h{sup -1}) in the freshwater marsh in winter. Flux of CH{sub 4} in winter (November to March the next year) was about 3.8%, 5.5%, and 2.2% of the whole year in 2003, 2004, and 2005, respectively. Emission of CH{sub 4} significantly increased during the freeze-thaw period (April-June), and was about 30.8%, 20.9%, and 20.6% of the whole year in 2003, 2004, and 2005, respectively. Standing water depth greatly governed interannual variation of CH{sub 4} emissions from marshes during the thaw-freeze period. Interannual variation of CH{sub 4} emissions was significant during the growing season (p<0.05). Standing water depth during April to June was a primary factor, which affected the interannual variation of CH{sub 4} flux during the growing season. Precipitation during the preceding non-growing season affected CH{sub 4} emission indirectly via standing water depth. (author)

  16. Bio-geomorphic feedback causes alternative stable landscape states: insights from coastal marshes and tidal flats

    Science.gov (United States)

    Temmerman, Stijn; Wang, Chen

    2014-05-01

    Many bio-geomorphic systems, such as hill slopes, river floodplains, tidal floodplains and dune areas, seem to be vulnerable to shifts between alternative bare and vegetated landscape states, and these shifts seem to be driven by bio-geomorphic feedbacks. Here we search for empirical evidence for alternative stable state behavior in intertidal flats and marshes, where bio-geomorphic interactions are known to be intense. Large-scale transitions have been reported worldwide between high-elevation vegetated marshes and low-elevation bare flats in intertidal zones of deltas, estuaries, and coastal embayments. It is of significant importance to understand and predict such transitions, because vegetated marshes provide significant services to coastal societies. Previous modeling studies suggest that the ecological theory of catastrophic shifts between alternative stable ecosystem states potentially explains the transition between bare flats and vegetated marshes. However, up to now only few empirical evidence exists. In our study, the hypothesis is empirically tested that vegetated marshes and bare tidal flats can be considered as alternative stable landscape states with rapid shifts between them. We studied historical records (1930s - 2000s) of intertidal elevation surveys and aerial pictures from the Westerschelde estuary (SW Netherlands). Our results demonstrated the existence of: (1) bimodality in the intertidal elevation distribution, i.e., the presence of two peaks in the elevation frequency distribution corresponding to a completely bare state and a densely vegetated state; (2) the relatively rapid transition in elevation when intertidal flats evolve from bare to vegetated states, with sedimentation rates that are 2 to 8 times faster than during the stable states; (3) a threshold elevation above which the shift from bare to vegetated state has a high chance to occur. Our observations demonstrate the abrupt non-linear shift between low-elevation bare flats and high

  17. Salt Marsh development studies at Waquoit Bay, Massachusetts: Influence of geomorphology on long-term plant community structure

    Science.gov (United States)

    Orson, Richard A.; Howes, Brian L.

    1992-11-01

    Stochastic events relating to beach formation and inlet dynamics have been the major factors influencing the development of the Waquoit Bay tidal marshes. This results from the physical structure of the Waquoit Bay system where tidal exchange is limited to one or two small inlets and is in contrast to marsh development in nearby Barnstable Marsh where direct unrestricted exchange with Cape Cod Bay has smoothed the effects of stochastic events on vegetation development. We contend that vegetation development in salt marshes where connections to adjacent waters are restricted will be dominated by abiotic factors (e.g. storms, sedimentation rates, etc.) while those marshes directly linked to open bodies of water and where alterations to hydrodynamic factors are gradual, autecological processes (e.g. interspecific competition) will dominate long-term plant community development. The results from the five marsh systems within the Waquoit Bay complex suggest that once a vegetation change occurs the new community tended to persist for long periods of time (100's-1000's years). Stability of the 'new' community appeared to depend upon the stability of the physical structure of the system and/or time between perturbations necessary to allow the slower autecological processes to have a discernable effect. In order for the plant community to persist as long as observed, the vegetation must also be exerting an influence on the processes of development. Increased production of roots and rhizomes and growth characteristics (density of culms) are some of the factors which help to maintain long-term species dominance. It is clear from this investigation that the structure of the plant community at any one point in time is dependent upon numerous factors including historical developmental influences. To properly assess changes to the present plant community or determine recent rates of accretion, historic developmental trends must be considered. The factors that have influenced the

  18. Forecasting tidal marsh elevation and habitat change through fusion of Earth observations and a process model

    Science.gov (United States)

    Byrd, Kristin B.; Windham-Myers, Lisamarie; Leeuw, Thomas; Downing, Bryan D.; Morris, James T.; Ferner, Matthew C.

    2016-01-01

    Reducing uncertainty in data inputs at relevant spatial scales can improve tidal marsh forecasting models, and their usefulness in coastal climate change adaptation decisions. The Marsh Equilibrium Model (MEM), a one-dimensional mechanistic elevation model, incorporates feedbacks of organic and inorganic inputs to project elevations under sea-level rise scenarios. We tested the feasibility of deriving two key MEM inputs—average annual suspended sediment concentration (SSC) and aboveground peak biomass—from remote sensing data in order to apply MEM across a broader geographic region. We analyzed the precision and representativeness (spatial distribution) of these remote sensing inputs to improve understanding of our study region, a brackish tidal marsh in San Francisco Bay, and to test the applicable spatial extent for coastal modeling. We compared biomass and SSC models derived from Landsat 8, DigitalGlobe WorldView-2, and hyperspectral airborne imagery. Landsat 8-derived inputs were evaluated in a MEM sensitivity analysis. Biomass models were comparable although peak biomass from Landsat 8 best matched field-measured values. The Portable Remote Imaging Spectrometer SSC model was most accurate, although a Landsat 8 time series provided annual average SSC estimates. Landsat 8-measured peak biomass values were randomly distributed, and annual average SSC (30 mg/L) was well represented in the main channels (IQR: 29–32 mg/L), illustrating the suitability of these inputs across the model domain. Trend response surface analysis identified significant diversion between field and remote sensing-based model runs at 60 yr due to model sensitivity at the marsh edge (80–140 cm NAVD88), although at 100 yr, elevation forecasts differed less than 10 cm across 97% of the marsh surface (150–200 cm NAVD88). Results demonstrate the utility of Landsat 8 for landscape-scale tidal marsh elevation projections due to its comparable performance with the other sensors

  19. Seasonal Variation in the Quality of Dissolved and Particulate Organic Matter Exchanged Between a Salt Marsh and Its Adjacent Estuary

    Science.gov (United States)

    Osburn, C. L.; Mikan, M.; Etheridge, J. R.; Burchell, M. R.; Birgand, F.

    2015-12-01

    Salt marshes are transitional ecosystems between terrestrial and marine environments. Along with mangroves and other vegetated coastal habitats, salt marshes rank among the most productive ecosystems on Earth, with critical global importance for the planet's carbon cycle. Fluorescence was used to examine the quality of dissolved and particulate organic matter (DOM and POM) exchanging between a tidal creek in a created salt marsh and its adjacent estuary in eastern North Carolina, USA. Samples from the creek were collected hourly over four tidal cycles in May, July, August, and October of 2011. Absorbance and fluorescence of chromophoric DOM (CDOM) and of base-extracted POM (BEPOM) served as the tracers for organic matter quality while dissolved organic carbon (DOC) and base-extracted particulate organic carbon (BEPOC) were used to compute fluxes. Fluorescence was modeled using parallel factor analysis (PARAFAC) and principle components analysis (PCA) of the PARAFAC results. Of nine PARAFAC components modeled, we used multiple linear regression to identify tracers for recalcitrant DOM; labile soil-derived source DOM; detrital POM; and planktonic POM. Based on mass balance, recalcitrant DOC export was 86 g C m-2 yr-1 and labile DOC export was 49 g C m-2 yr-1. The marsh also exported 41 g C m-2 yr-1 of detrital terrestrial POC, which likely originated from lands adjacent to the North River estuary. Planktonic POC export from the marsh was 6 g C m-2 yr-1. Using the DOM and POM quality results obtained via fluorescence measurements and scaling up to global salt marsh area, we estimated that the potential release of CO2 from the respiration of salt marsh DOC and POC transported to estuaries could be 11 Tg C yr-1, roughly 4% of the recently estimated CO2 release for marshes and estuaries globally.

  20. Potential effects of sea-level rise on plant productivity: Species-specific responses in northeast Pacific tidal marshes

    Science.gov (United States)

    Janousek, Christopher; Buffington, Kevin J.; Thorne, Karen M.; Guntenspergen, Glenn R.; Takekawa, John Y.; Dugger, Bruce D.

    2016-01-01

    Coastal wetland plants are adapted to varying degrees of inundation. However, functional relationships between inundation and productivity are poorly characterized for most species. Determining species-specific tolerances to inundation is necessary to evaluate sea-level rise (SLR) effects on future marsh plant community composition, quantify organic matter inputs to marsh accretion, and inform predictive modeling of tidal wetland persistence. In 2 macrotidal estuaries in the northeast Pacific we grew 5 common species in experimental mesocosms across a gradient of tidal elevations to assess effects on growth. We also tested whether species abundance distributions along elevation gradients in adjacent marshes matched productivity profiles in the mesocosms. We found parabolic relationships between inundation and total plant biomass and shoot counts in Spartina foliosa and Bolboschoenus maritimus in California, USA, and in Carex lyngbyei in Oregon, USA, with maximum total plant biomass occurring at 38, 28, and 15% time submerged, respectively. However, biomass of Salicornia pacifica and Juncus balticus declined monotonically with increasing inundation. Inundation effects on the ratio of belowground to aboveground biomass varied inconsistently among species. In comparisons of field distributions with mesocosm results, B. maritimus, C. lyngbyei and J. balticus were abundant in marshes at or above elevations corresponding with their maximum productivity; however, S. foliosa and S. pacifica were frequently abundant at lower elevations corresponding with sub-optimal productivity. Our findings show species-level differences in how marsh plant growth may respond to future SLR and highlight the sensitivity of high marsh species such as S. pacifica and J. balticus to increases in flooding.

  1. A one-dimensional biomorphodynamic model of tidal flats: Sediment sorting, marsh distribution, and carbon accumulation under sea level rise

    Science.gov (United States)

    Zhou, Zeng; Ye, Qinghua; Coco, Giovanni

    2016-07-01

    We develop a biomorphodynamic model to investigate sediment and vegetation dynamics on a schematic intertidal flat characterized by an initially well-mixed sand-mud mixture. Major interactions between tides, wind waves, salt marshes, sediment transport and sea level rise (SLR) are taken into account. For a bare flat under only tidal action, the model predicts a convex cross-shore profile with the surficial distribution of mud and sand on the upper and lower part of the intertidal flat, respectively. When wind waves are strong, the intertidal flat is highly eroded resulting in a concave profile near the high water mark. This behavior is pronouncedly altered when the intertidal flat is vegetated with the presence of salt marshes. Numerical results suggest that a considerable amount of mud can still remain in the vegetated region even when wave action is strong. A steeper transition zone forms at the boundary between salt marshes and bare flats because of the differential sediment deposition in the two neighboring regions. The inclusion of wind waves is found to considerably enhance the size of the marsh-edge transition zone. For the numerical experiments designed in this study, the profile shape and sediment sorting behavior of tidal flats are not significantly modified by a gradual rising sea level. However, the impacts of SLR on vegetated tidal flats are still manifold: (a) driving the landward migration of intertidal zone and salt marshes; (b) enhancing sediment erosion on intertidal flats; and (c) drowning salt marshes under limited sediment supply with the constrain of seawalls. Finally, model results suggest that organic carbon accumulation on marshlands may be enhanced with an increasing SLR rate provided that salt marshes are not drowned.

  2. Seasonal variations of nitrous oxide fluxes and soil denitrification rates in subtropical freshwater and brackish tidal marshes of the Min River estuary.

    Science.gov (United States)

    Wang, Xuming; Hu, Minjie; Ren, Hongchang; Li, Jiabing; Tong, Chuan; Musenze, Ronald S

    2018-03-01

    Estuarine tidal marshes provide favorable conditions for nitrous oxide (N 2 O) production. Saltwater intrusion caused by sea-level rise would exert complex effects on the production and emission of N 2 O in estuarine tidal marshes; however, few studies have been conducted on its effects on N 2 O emissions. Salinity gradients are a common occurrence in estuarine tidal marshes. Studies on production and emission of N 2 O in tidal marshes with different salinities may elucidate the impact of saltwater intrusion on the emission of greenhouse gases. This study explores the seasonal variations of N 2 O fluxes and soil denitrification rates in freshwater (Daoqingzhou wetland) and brackish (Shanyutan wetland) tidal marshes dominated by Cyperus malaccensis var. brevifolius (shichito matgrass) in the Min River estuary, southeastern China. N 2 O fluxes in both marshes showed strong temporal variability. The highest N 2 O fluxes were observed in the hot and wet summer months, whereas the lowest fluxes were observed in the cold winter and autumn months. N 2 O fluxes from the freshwater marsh (48.81±9.01μgm -2 h -1 ) were significantly higher (ptidal wetlands and exert a negative feedback on the climate system. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Long-Term Spartina alterniflora biomass, productivity, porewater chemistry and marsh elevation in North Inlet Estuary, Georgetown, SC: 1984-2011.

    Data.gov (United States)

    Baruch Institute for Marine and Coastal Sciences, Univ of South Carolina — The salt marsh in the North Inlet estuary was sampled approximately monthly for estimates of biomass, productivity, porewater chemistry, and salt marsh elevation....

  4. Evaluation of the marsh deer stifle joint by imaging studies and gross anatomy.

    Science.gov (United States)

    Shigue, D A; Rahal, S C; Schimming, B C; Santos, R R; Vulcano, L C; Linardi, J L; Teixeira, C R

    2015-12-01

    This study aimed to evaluate the stifle joint of marsh deer using imaging studies and in comparison with gross anatomy. Ten hindlimbs from 5 marsh deer (Blastocerus dichotomus) were used. Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed in each stifle joint. Two hindlimbs were dissected to describe stifle gross anatomy. The other limbs were sectioned in sagittal, dorsal or transverse planes. In the craniocaudal radiographic view, the lateral femoral condyle was broader than the medial femoral condyle. The femoral trochlea was asymmetrical. Subsequent multiplanar reconstruction revealed in the cranial view that the external surface of the patella was roughened, the medial trochlea ridge was larger than the lateral one, and the extensor fossa at the lateral condyle was next to the lateral ridge. The popliteal fossa was better visualized via the lateral view. Sagittal MRI images identified lateral and medial menisci, caudolateral and craniomedial bundles of cranial cruciate ligament, caudal cruciate ligament, patellar ligament and common extensor tendon. In conclusion, the marsh deer stifle presents some anatomical characteristics of the ovine stifle joint. © 2014 Blackwell Verlag GmbH.

  5. The link between water quality and tidal marshes in a highly impacted estuary.

    Science.gov (United States)

    Meire, Patrick; Maris, Tom; van Damme, Stefan; Jacobs, Sander; Cox, Tom; Struyf, Eric

    2010-05-01

    The Schelde estuary is one of the most heavily impacted estuaries in Europe. During several decades, untreated waste water from large cities (e.g. Brussels, Antwerp, Valenciennes, Lille) and industries was discharged in the river. As a result, the Schelde estuary has the reputation of being one of the most polluted estuaries in Europe. For a long time (approx. 1950 - 1995) all forms of higher life (macro-invertebrates and fish) were absent in the fresh and brackish parts of the estuary. Due to European legislation, a large part of the sewage water is now treated resulting in a significant recovery of water quality in the estuary. However, next to water quality, the estuary also suffered serious habitat losses during the last decades, mostly due to economic development and changing hydrological conditions causing more erosion. Over the last fifteen years, the management of the estuary has changed fundamentally. It is now more and more focused on the restoration of ecosystem services. In this presentation we will document the changes in water quality over the last 50 years and summarize recent work on the role of tidal marshes on water quality within the freshwater part of the Schelde estuary. Our results stress the important of taking into account ecosystem services and habitat restoration for long-term estuarine management. .After decades of high inorganic nutrient concentrations and recurring anoxia and hypoxia, we observed a paradoxical increase in chlorophyll-a concentrations with decreasing nutrient inputs, indicating a regime shift. Our results indicate that the recovery of a hypereutrophied systems towards a classical eutrophied state, needs the reduction of waste loads below certain thresholds. Paradoxically, phytoplankton production was inhibited by high ammonia or low oxygen concentrations. The system state change is accompanied by large fluctuations in oxygen concentrations. The improved water quality resulted in a remarkable recovery of different groups

  6. On autochtonous organic production and its implication for the consolidation of temperate salt marshes

    DEFF Research Database (Denmark)

    Bartholdy, Jesper; Bartholdy, Anders; Kim, Daehyun

    2014-01-01

    decomposes with a decreasing organic content until about 15 cm below the surface. Hereunder the decomposition of organic material seems to stabilize at a very low level. The constant rate of the below ground organic production results in a larger concentration of this type of organic matter in the slowest......The organic production related to minerogene salt marsh deposits represents a challenge to all attempts to model the development of these areas, and evaluate their chances of survival under different sea level scenarios. Salt marsh deposits on a typical temperate backbarrier saltmarsh area...... at the Skallingen barrierspit (Denmark) were investigated for autochthonous or below ground organic production, which was found to have a mean value of 0.14 kg m− 2 y− 1 or about 0.1 mm y− 1. This production is concentrated in the upper approximately 5 cm of the salt marsh. Below this level the organic material...

  7. Long-term hydrologic effects on marsh plant community structure in the southern Everglades

    Science.gov (United States)

    Busch, David E.; Loftus, W.F.; Bass, O.L.

    1998-01-01

    Although large-scale transformation of Everglades landscapes has occurred during the past century, the patterns of association among hydrologic factors and southern Everglades freshwater marsh vegetation have not been well-defined. We used a 10-year data base on the aquatic biota of Shark Slough to classify vegetation and describe plant community change in intermediate- to long-hydroperiod Everglades marshes. Study area marsh vegetation was quantitatively grouped into associations dominated by 1) Cladium jamaicense, 2) a group of emergents including Eleocharis cellulosa, Sagittaria lancifolia, and Rhyncospora tracyi, 3) taxa associated with algal mats (Utricularia spp. and Bacopa caroliniana), and 4) the grasses Panicum hemitomon and Paspalidium geminatum. During the decade evaluated, the range of water depths that characterized our study sites approached both extremes depicted in the 40-year hydrologic record for the region. Water depths were near the long-term average during the mid-1980s, declined sharply during a late 1980s drought, and underwent a prolonged increase from 1991 through 1995. Overall macrophyte cover varied inversely with water depth, while the response of periphyton was more complex. An ordination analysis, based on plant species abundance, revealed that study area vegetation structure was associated with hydrologic patterns. Marsh plant community structure showed evidence of cyclic interannual variation corresponding to hydrologic change over the decade evaluated. Lower water depths, the occurrence of marl substrates, and high periphyton cover were correlated. These factors contributed to reduced macrophyte cover in portions of the study area from which water had been diverted.

  8. Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance

    Science.gov (United States)

    Krauss, Ken W.; Holm, Guerry O.; Perez, Brian C.; McWhorter, David E.; Cormier, Nicole; Moss, Rebecca; Johnson, Darren; Neubauer, Scott C; Raynie, Richard C

    2016-01-01

    Coastal marshes take up atmospheric CO2 while emitting CO2, CH4, and N2O. This ability to sequester carbon (C) is much greater for wetlands on a per-area basis than from most ecosystems, facilitating scientific, political, and economic interest in their value as greenhouse gas sinks. However, the greenhouse gas balance of Gulf of Mexico wetlands is particularly understudied. We describe the net ecosystem exchange (NEEc) of CO2 and CH4 using eddy covariance (EC) in comparison with fluxes of CO2, CH4, and N2O using chambers from brackish and freshwater marshes in Louisiana, USA. From EC, we found that 182 g C m-2 y-1 was lost through NEEc from the brackish marsh. Of this, 11 g C m-2 y-1 resulted from net CH4 emissions and the remaining 171 g C m-2 y-1 resulted from net CO2 emissions. In contrast, -290 g C m2 y-1 was taken up through NEEc by the freshwater marsh, with 47 g C m-2 y-1 emitted as CH4 and -337 g C m-2 y-1 taken up as CO2. From chambers, we discovered that neither site had large fluxes of N2O. Sustained-flux greenhouse gas accounting metrics indicated that both marshes had a positive (warming) radiative balance, with the brackish marsh having a substantially greater warming effect than the freshwater marsh. That net respiratory emissions of CO2 and CH4 as estimated through chamber techniques were 2-4 times different from emissions estimated through EC requires additional understanding of the artifacts created by different spatial and temporal sampling footprints between techniques.

  9. Sediment Accretion, Carbon Sequestration, and Resilience to Sea Level Rise in Natural and Recently Restored Tidal Marshes

    Science.gov (United States)

    Poppe, K.; Rybczyk, J.; Parr, L.; Merrill, A.

    2017-12-01

    Tidal marshes are typically productive and depositional environments potentially conducive to high rates of carbon sequestration. Though they have been recognized globally for their ability to store "blue carbon", there is a paucity of comprehensive site-scale data from the Pacific Northwest U.S. Here we report carbon stocks and sequestration rates for an existing and a recently restored brackish marsh in the Stillaguamish River Estuary, in Puget Sound, Washington. The Stillaguamish River discharges into the Port Susan Bay Preserve which contains a 150-acre tidal marsh restoration site that was reintroduced to the tidal regime in 2012 from its previous use as diked and drained farmland. We hypothesized that the restoration would not only maximize carbon storage in former tidal wetlands but also, through the accumulation of organic and mineral matter, enhance these systems' resilience to rising sea levels. We collected sediment cores from 13 sites across the estuary, within and outside of the restoration area, to determine bulk density, organic and carbon content with depth, long-term accretion rates, and belowground biomass. We also measured aboveground net primary productivity. Carbon stocks at each site were partitioned into three components as recommended by the IPCC: aboveground biomass, belowground biomass, and sediment carbon. We additionally measured elevation change with surface elevation tables (SETs). Mean sediment carbon stocks in the upper 30 cm of sediment within the restoration area (6.45 kg C/m2) were similar to those measured in the adjacent natural marsh (6.82 kg C/m2). However, mean elevation change, as measured by SETs, were substantially higher in the restoration area (3.10 cm/yr) than in the natural marsh sites (0.79 cm/yr). As a result, carbon accumulation rates were also higher in the restoration area (821 g C/m2/yr) compared to the natural marsh sites (195 g C/m2/yr).

  10. Book reviews: Marsh David, The EURO – The Politics of the New Global Currency

    OpenAIRE

    Lazar, Isadora

    2011-01-01

    The EURO – The Politics of the New Global Currency, written by David Marsh and published in both English and German, is a very thorough chronicle of the birth of the European common currency, from its early days, almost half a century before, and of its development until nowadays and even beyond, as it includes considerations on short term dynamics. David Marsh describes the story of the euro in a very complex manner, through a detailed, comprehensive and up to date analysis of the gathered d...

  11. Mercury uptake and allocation in Juncus maritimus: implications for phytoremediation and restoration of a mercury contaminated salt marsh.

    Science.gov (United States)

    Figueira, Etelvina; Freitas, Rosa; Pereira, Eduarda; Duarte, Armando

    2012-08-01

    Juncus maritimus is the most abundant macrophyte in Laranjo bay, a Portuguese salt marsh heavily polluted by mercury (Hg). With the aim to elucidate the role of this species in the salt marsh Hg cycling and restoration, plants were harvested between March 2006 and January 2008 from four locations differing in Hg contamination. Metal uptake and distribution between plant organs were evaluated, biomass and Hg pools were also determined. Results showed that J. maritimus may influence the sediment pH and Eh, thus increasing the Hg available for uptake. Most (95-98%) of the absorbed Hg was retained belowground, phytostabilizing the metal and reducing the amount of Hg in the sediments. These results suggest that in salt marshes dominated by J. maritimus the approach could be phytostabilization, where these plants can be used to immobilize metals and store them belowground, reducing the pool of bioavailable Hg within contaminated marshes and acting as a sink rather than a source of contamination to the surrounding areas.

  12. Macroinvertebrate Prey Availability and Fish Diet Selectivity in Relation to Environmental Variables in Natural and Restoring North San Francisco Bay Tidal Marsh Channels

    Directory of Open Access Journals (Sweden)

    Emily R. Howe

    2014-03-01

    Full Text Available Tidal marsh wetlands provide important foraging habitat for a variety of estuarine fishes. Prey organisms include benthic–epibenthic macroinvertebrates, neustonic arthropods, and zooplankton. Little is known about the abundance and distribution of interior marsh macroinvertebrate communities in the San Francisco Estuary (estuary. We describe seasonal, regional, and site variation in the composition and abundance of neuston and benthic–epibenthic macroinvertebrates that inhabit tidal marsh channels, and relate these patterns to environmental conditions. We also describe spatial and temporal variation in diets of marsh-associated inland silverside, yellowfin goby, and western mosquitofish. Fish and invertebrates were sampled quarterly from October 2003 to June 2005 at six marsh sites located in three river systems of the northern estuary: Petaluma River, Napa River, and  the west Delta. Benthic/epibenthic macroinvertebrates and neuston responded to environmental variables related to seasonal changes (i.e., temperature, salinity, as well as those related to marsh structure (i.e., vegetation, channel edge. The greatest variation in abundance occurred seasonally for neuston and spatially for benthic–epibenthic organisms, suggesting that each community responds to different environmental drivers. Benthic/epibenthic invertebrate abundance and diversity was lowest in the west Delta, and increased with increasing salinity. Insect abundance increased during the spring and summer, while Collembolan (springtail abundance increased during the winter. Benthic/epibenthic macroinvertebrates dominated fish diets, supplemented by insects, with zooplankton playing a minor role. Diet compositions of the three fish species overlapped considerably, with strong selection indicated for epibenthic crustaceans—a surprising result given the typical classification of Menidia beryllina as a planktivore, Acanthogobius flavimanus as a benthic predator, and Gambusia

  13. Changes in assimilation of C3 marsh plants by resident fishes in estuarine systems with distinct hydrogeomorphology features.

    Directory of Open Access Journals (Sweden)

    Adna Ferreira Garcia

    2015-11-01

    Full Text Available Although saltmarshes are widely recognized as important habitats providing shelter for estuarine organisms and protection against predators, there is still no consensus on the trophic value of marsh plants for estuarine food webs. We employed stable isotopes to evaluate differences in assimilation of nutrients derived from marsh plants with C3 (Juncus acutus, Scirpus maritimus, Scirpus olneyi and C4 (Spartina densiflora photosynthetic pathways by resident fishes in three estuaries with contrasting hydrogeomorphology characteristics. Carbon (δ13C and nitrogen (δ15N stable isotope ratios of basal food sources (C3 and C4 marsh plants, macroalgae, seagrass and seston and estuarine resident fishes (Achirus garmani, Atherinella brasiliensis, Genidens genidens, Ctenogobius shufeldti, Jenynsia multidentata, Odonthestes argentinensis were analyzed in two choked lagoons (Tramandai-29°S, Patos-30°S and a coastal river (Chui-33°S. Average δ13C values of consumers were statistically significant higher in the two choked-type estuaries (Tramandaí: -16.11; Patos: -15.82 than in the coastal river (Chui: -24.32 (p0.292. SIAR mixing models revealed that the most assimilated basal food sources by consumers in the choked-type lagoon estuaries were a pool of 13C enriched food sources (macroalgae, C4 marsh and seagrass and seston (95% credibility interval: 0.38 to 0.80 and 0.00 to 0.54, respectively. In contrast, nutrients derived from C3-marsh plants were the main basal food source assimilated by estuarine resident fishes at the coastal river (0.33 to 0.87. These findings could be explained by the absence of extensive shallow embayments and a steeper slope at the coastal river that could promote higher transport of C3-marsh detritus and, consequently, higher assimilation by estuarine fishes. In contrast, detritus derived from C3 marsh plants could be trapped in the upper intertidal zone of choked-typed estuaries and, consequently, be less available for aquatic

  14. Effects of wind waves versus ship waves on tidal marsh plants: A flume study on different life stages of

    NARCIS (Netherlands)

    Silinski, A.; Heuner, M.; Schoelynck, J.; Puijalon, S.; Schröder, U.; Fuchs, E.; Troch, P.; Bouma, T.J.; Meire, P.; Temmerman, S.

    2015-01-01

    Recent research indicates that many ecosystems, including intertidal marshes, follow the alternative stable states theory. This theory implies that thresholds of environmental factors can mark a limit between two opposing stable ecosystem states, e.g. vegetated marshes and bare mudflats. While

  15. Importance of biogeomorphic and spatial properties in assessing a tidal salt marsh vulnerability to sea-level rise

    Science.gov (United States)

    Thorne, Karen M.; Elliott-Fisk, Deborah L.; Wylie, Glenn D.; Perry, William M.; Takekawa, John Y.

    2014-01-01

    We evaluated the biogeomorphic processes of a large (309 ha) tidal salt marsh and examined factors that influence its ability to keep pace with relative sea-level rise (SLR). Detailed elevation data from 1995 and 2008 were compared with digital elevation models (DEMs) to assess marsh surface elevation change during this time. Overall, 37 % (113 ha) of the marsh increased in elevation at a rate that exceeded SLR, whereas 63 % (196 ha) of the area did not keep pace with SLR. Of the total area, 55 % (169 ha) subsided during the study period, but subsidence varied spatially across the marsh surface. To determine which biogeomorphic and spatial factors contributed to measured elevation change, we collected soil cores and determined percent and origin of organic matter (OM), particle size, bulk density (BD), and distance to nearest bay edge, levee, and channel. We then used Akaike Information Criterion (AICc) model selection to assess those variables most important to determine measured elevation change. Soil stable isotope compositions were evaluated to assess the source of the OM. The samples had limited percent OM by weight (-3, indicating that the soils had high mineral content with a relatively low proportion of pore space. The most parsimonious model with the highest AICc weight (0.53) included distance from bay's edge (i.e., lower intertidal) and distance from levee (i.e., upper intertidal). Close proximity to sediment source was the greatest factor in determining whether an area increased in elevation, whereas areas near landward levees experienced subsidence. Our study indicated that the ability of a marsh to keep pace with SLR varied across the surface, and assessing changes in elevation over time provides an alternative method to long-term accretion monitoring. SLR models that do not consider spatial variability of biogeomorphic and accretion processes may not correctly forecast marsh drowning rates, which may be especially true in modified and urbanized

  16. Assessing saltmarsh resilience to sea-level rise by examining sediment transport trends in the Great Marsh, MA.

    Science.gov (United States)

    Hughes, Z. J.; Georgiou, I. Y.; Gaweesh, A.; Hanegan, K.; FitzGerald, D.; Hein, C. J.

    2017-12-01

    Under accelerating sea-level rise (SLR), marshes are vulnerable to increased inundation, dependent on their ability to accrete vertically or expand into upland areas. Accretion is a function of organic and inorganic contributions from plant biomass and suspended sediment deposition, respectively. Along the east coast of the US, present rates of SLR are higher than they have been for over 1000 years and are expected to increase in the near future. To predict the resilience of saltmarshes, we urgently need improved understanding of spatial patterns of sediment transport and deposition within these systems. This study examines time-series of suspended sediment concentration and flow collected using ADCP-OBS units, deployed throughout the Great Marsh System. We compare the data to model results and observations of short and long term deposition throughout the system. Field observations show that tidal amplitude and phase vary throughout the Great Marsh. Tidal asymmetry increases inland from the estuary mouth, and the maximum phase lag is 2 hours. This effect is strongest during low slack tide; with a delay of only 30-45 minutes at high tide. Tidal velocities exhibit strong asymmetry, reflected in pulses of sediment movement. Sediment transport initiates at mid ebb, peaking 1.5-2.5 hours later, decreasing through low slack tide for 7-9 hours until high slack tide. The results have broad implications for the potential input of inorganic sediment to the marsh platform. Results from a validated Delft3D model reproduce field observations and expand spatial sediment transport trends. We experiment by releasing sediment in different parts of the estuary, mimicking marsh edge or tidal flat erosion, and tracking mud and sand transport trajectories. Sands remains proximal to the erosion site, whereas mud is more mobile and travels farther, reaching the inlet within days of erosion. Longer simulations suggest that despite higher mobility, muds remain mostly in the channels and

  17. Salt Marsh Sustainability in New England: Progress and Remaining Challenges

    Science.gov (United States)

    Natural resource managers, conservationists, and scientists described marsh loss and degradation in many New England coastal systems at the 2014 “Effects of Sea Level Rise on Rhode Island’s Salt Marshes” workshop, organized by the Narragansett Bay National Estuarine Research Rese...

  18. Estimating Carbon Stocks and Atmospheric Exchange of Depressional Marshes on the Central Florida Landscape

    Science.gov (United States)

    Benscoter, B.; McClellan, M. D.; Benavides, V.; Harshbarger, D.; Comas, X.

    2014-12-01

    Depressional marshes are ubiquitous throughout central and south Florida. Often distributed within a matrix of sandy pine flatwoods and hammocks, these wetlands have a seasonally variable water table, alternating between inundation and complete drydown. Though these landforms are typically small individually, they comprise a substantial component of the landscape and provide vital habitat for an array of flora and fauna. Given their fluctuating hydrology, conditions for soil and plant carbon (C) exchange mechanisms can vary greatly both spatially and temporally. In this study, we are developing a C budget for depressional marsh landforms by assessing ecosystem carbon exchange along an ecotone gradient and quantifying belowground C stocks using non-invasive geophysical methods (ground penetrating radar, GPR) at the Disney Wilderness Preserve (DWP) in Kissimmee, FL, USA. Using a series of closed chambers transecting the marsh from the center outward into the surrounding flatwoods, we are quantifying the effects of seasonal water table change on the magnitude of C exchange. Three dimensional GPR surveys were used to quantify peat layer thickness, and were constrained with direct core sampling to verify subsurface lithology and to assess peat C content. Using the relationship between landform surface area and belowground C volume, we assessed the cumulative C storage in depressional marshes across the DWP landscape. In conjunction with a nearby eddy covariance tower and seasonal hydrologic data, these response functions will help to evaluate the contribution of these small but widespread landscape features on regional C cycling.

  19. Effects of marsh pond terracing on coastal wintering waterbirds before and after Hurricane Rita.

    Science.gov (United States)

    O'Connell, Jessica L; Nyman, John A

    2011-11-01

    From February to March 2005-2006, we surveyed wintering waterbirds to test effects of terracing on coastal pond use before and after Hurricane Rita. Marsh terracing is intended to slow coastal marsh loss in the Chenier Plain by slowing marsh erosion and encouraging vegetation expansion. Terraces also increase marsh edge in ponds, possibly benefiting waterbirds. We monitored paired terraced and unterraced ponds in three sites within southwestern Louisiana's Chenier Plain. Waterbirds were 75% more numerous in terraced than unterraced ponds. Waterbird richness was similar among ponds when corrected for number of individuals, suggesting terracing increased bird density but did not provide habitat unique from unterraced ponds. Birds were 93% more numerous following Hurricane Rita, mostly due to an influx of migrating waterfowl. Year round residents were similar in number before and after Hurricane Rita. Resident richness did not differ among years after correcting for number of observed individuals. Wading and dabbling foragers were more abundant in terraced ponds and these two guilds represented 74% of birds observed. We detected no difference among ponds for other guilds, i.e., probing, aerial, and diving foragers. Increasing proportion of mash edge increased bird density disproportionately: On average ponds with 10% edge had 6 birds observed and ponds with 30% edge had 16 birds observed. Terraces increased habitat interspersion and were an effective tool for increasing numbers of wintering waterfowl and wading birds. The extent to which terraces were sustainable following hurricane forces is unknown.

  20. Effects of Marsh Pond Terracing on Coastal Wintering Waterbirds Before and After Hurricane Rita

    Science.gov (United States)

    O'Connell, Jessica L.; Nyman, John A.

    2011-11-01

    From February to March 2005-2006, we surveyed wintering waterbirds to test effects of terracing on coastal pond use before and after Hurricane Rita. Marsh terracing is intended to slow coastal marsh loss in the Chenier Plain by slowing marsh erosion and encouraging vegetation expansion. Terraces also increase marsh edge in ponds, possibly benefiting waterbirds. We monitored paired terraced and unterraced ponds in three sites within southwestern Louisiana's Chenier Plain. Waterbirds were 75% more numerous in terraced than unterraced ponds. Waterbird richness was similar among ponds when corrected for number of individuals, suggesting terracing increased bird density but did not provide habitat unique from unterraced ponds. Birds were 93% more numerous following Hurricane Rita, mostly due to an influx of migrating waterfowl. Year round residents were similar in number before and after Hurricane Rita. Resident richness did not differ among years after correcting for number of observed individuals. Wading and dabbling foragers were more abundant in terraced ponds and these two guilds represented 74% of birds observed. We detected no difference among ponds for other guilds, i.e., probing, aerial, and diving foragers. Increasing proportion of mash edge increased bird density disproportionately: On average ponds with 10% edge had 6 birds observed and ponds with 30% edge had 16 birds observed. Terraces increased habitat interspersion and were an effective tool for increasing numbers of wintering waterfowl and wading birds. The extent to which terraces were sustainable following hurricane forces is unknown.

  1. Gut-Associated Microbial Symbionts of the Marsh Fiddler Crab, Uca Pugnax

    National Research Council Canada - National Science Library

    Gunman, Lara K

    2004-01-01

    .... The overarching goal of this thesis was to characterize the ecology and genetic diversity of resident gut microbes to advance our understanding of their interactions with their host, the marsh fiddler crab, Uca pugnax...

  2. Factors affecting marsh vegetation at the Liberty Island Conservation Bank in the Cache Slough region of the Sacramento–San Joaquin Delta, California

    Science.gov (United States)

    Orlando, James L.; Drexler, Judith Z.

    2017-07-07

    The Liberty Island Conservation Bank (LICB) is a tidal freshwater marsh restored for the purpose of mitigating adverse effects on sensitive fish populations elsewhere in the region. The LICB was completed in 2012 and is in the northern Cache Slough region of the Sacramento–San Joaquin Delta. The wetland vegetation at the LICB is stunted and yellow-green in color (chlorotic) compared to nearby wetlands. A study was done to investigate three potential causes of the stunted and chlorotic vegetation: (1) improper grading of the marsh plain, (2) pesticide contamination from agricultural and urban inputs upstream from the site, (3) nitrogen-deficient soil, or some combination of these. Water samples were collected from channels at five sites, and soil samples were collected from four wetlands, including the LICB, during the summer of 2015. Real-time kinematic global positioning system (RTK-GPS) elevation surveys were completed at the LICB and north Little Holland Tract, a closely situated natural marsh that has similar hydrodynamics as the LICB, but contains healthy marsh vegetation.The results showed no significant differences in carbon or nitrogen content in the surface soils or in pesticides in water among the sites. The elevation survey indicated that the mean elevation of the LICB was about 26 centimeters higher than that of the north Little Holland Tract marsh. Because marsh plain elevation largely determines the hydroperiod of a marsh, these results indicated that the LICB has a hydroperiod that differs from that of neighboring north Little Holland Tract marsh. This difference in hydroperiod contributed to the lower stature and decreased vigor of wetland vegetation at the LICB. Although the LICB cannot be regraded without great expense, it could be possible to reduce the sharp angle of the marsh edge to facilitate deeper and more frequent tidal flooding along the marsh periphery. Establishing optimal elevations for restored wetlands is necessary for obtaining

  3. Salt marsh as a coastal filter for the oceans: changes in function with experimental increases in nitrogen loading and sea-level rise.

    Science.gov (United States)

    Nelson, Joanna L; Zavaleta, Erika S

    2012-01-01

    Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N) before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH(4)NO(3))-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a) aboveground biomass, b) plant tissue N concentrations, c) N stock sequestered in plants, and d) shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication.

  4. Mapping the change of Phragmites australis live biomass in the lower Mississippi River Delta marshes

    Science.gov (United States)

    Ramsey, Elijah W.; Rangoonwala, Amina

    2017-07-28

    Multiyear remote sensing mapping of the normalized difference vegetation index (NDVI) was carried out as an indicator of live biomass composition of the Phragmites australis (hereafter Phragmites) marsh in the lower Mississippi River Delta (hereafter delta) from 2014 to 2017. Maps of NDVI change showed that the Phragmites condition was fairly stable between May 2014 and July 2015. From July 2015 to April 2016 NDVI change indicated Phragmites suffered a widespread decline in the live biomass proportion.  Between April and September 2016, most marsh remained unchanged from the earlier period or showed improvement; although there were pockets of continued decline scattered throughout the lower delta. From September 2016 to May 2017 a pronounced and widely exhibited decline in the condition of Phragmites marsh again occurred throughout the lower delta. This final NDVI change mapping supported field observations of Phragmites decline during the same period.

  5. A multi-proxy study of sedimentary humic substances in the salt marsh of the Changjiang Estuary, China

    Science.gov (United States)

    Zhang, Yaoling; Du, Jinzhou; Zhao, Xin; Wu, Wangsuo; Peng, Bo; Zhang, Jing

    2014-12-01

    To better understand the origin, composition, and reactivity of sedimentary humic substances (HSs) in salt marshes in the Changjiang Estuary, HS samples were isolated from a sediment core that was collected from the Eastern Chongming salt marsh. Chemical and spectroscopic methods were used to analyze the features of these HSs. The results indicate that the studied HSs in the salt marsh sediments are mainly terrestrial-derived and that the sedimentary organic matter (SOM) in the top layer may contain more organic matter from marine sources and/or autochthonous materials due to the dramatic decreasing of the sediment supply as a result of damming. The degradation of labile carbohydrates and proteins and the preservation of refractory lignin components dominate the early diagenetic reactions of SOM in the salt marsh area. The average contents of the carboxylic groups in FAs and HAs are 11.64 ± 1.08 and 7.13 ± 0.16 meq/gC, and those of phenolic groups are 1.95 ± 0.13 and 2.40 ± 0.44 meq/gC, respectively. The content of carboxylic groups increased with increasing depth, while there were no obvious changes in the content of phenolic groups. The average concentration of total proton-binding sites is approximately 12.5 μmol/g sediment for the studied HSs. These values may provide insight into the migration and fate of HS-bound contaminants in sediments and the overlying sea water in the salt marsh areas of the Changjiang Estuary.

  6. Carbon stocks in mangroves, salt marshes, and salt barrens in Tampa Bay, Florida, USA: Vegetative and soil characteristics.

    Science.gov (United States)

    Moyer, R. P.; Radabaugh, K.; Chappel, A. R.; Powell, C.; Bociu, I.; Smoak, J. M.

    2017-12-01

    When compared to other terrestrial environments, coastal "blue carbon" habitats such as salt marshes and mangrove forests sequester disproportionately large amounts of carbon as standing plant biomass and sedimentary peat deposits. This study quantified total carbon stocks in vegetation and soil of 17 salt marshes, salt barrens, and mangrove forests in Tampa Bay, Florida, USA. The sites included natural, restored, and created wetlands of varying ages and degrees of anthropogenic impacts. The average vegetative carbon stock in mangrove forests was 60.1 ± 2.7 Mg ha-1. Mangrove forests frequently consisted of a few large Avicennia germinans trees with smaller, abundant Rhizophora mangle and/or Laguncularia racemosa trees. The average vegetative carbon stock was 11.8 ± 3.7 Mg ha-1 for salt marshes and 2.0 ± 1.2 Mg ha-1 for salt barrens. Vegetative carbon did not significantly differ between natural and newly created salt marsh habitats, indicating that mature restored wetlands can be included with natural wetlands for the calculation of vegetative carbon in coastal blue carbon assessments. Peat deposits were generally less than 50 cm thick and organic content rapidly decreased with depth in all habitats. Soil in this study was analyzed in 1 cm intervals; the accuracy of subsampling or binning soil into depth intervals of 2-5 cm was also assessed. In most cases, carbon stock values obtained from these larger sampling intervals were not statistically different from values obtained from sampling at 1 cm intervals. In the first 15 cm, soil in mangrove forests contained an average of 15.1% organic carbon by weight, salt marshes contained 6.5%, and salt barrens contained 0.8%. Total carbon stock in mangroves was 187.1±17.3 Mg ha-1, with 68% of that carbon stored in soil. Salt marshes contained an average of 65.2±25.3 Mg ha-1 (82% soil carbon) and salt barrens had carbon stocks of 21.4±7.4 Mg ha-1 (89% soil carbon). These values were much lower than global averages for

  7. Seed dispersal by small herbivores and tidal water : are they important filters in the assembly of salt-marsh communities?

    NARCIS (Netherlands)

    Chang, ER; Zozaya, EL; Kuijper, DPJ; Bakker, JP

    1. Characteristics of internal seed dispersal (endozoochory) by European Brown Hares were compared with similar dispersal by Brent Geese. Hares deposited more seeds of mid-successional, perennial, high-marsh species than did geese, which deposited more seeds of early successional, annual, low-marsh

  8. Seed dispersal by small herbivores and tidal water: Are they important filters in the assembly of salt-marsh communities?

    NARCIS (Netherlands)

    Chang, E.R.; Zozaya, E.L.; Kuijper, D.P.J.; Bakker, J.P.

    2005-01-01

    1. Characteristics of internal seed dispersal (endozoochory) by European Brown Hares were compared with similar dispersal by Brent Geese. Hares deposited more seeds of mid-successional, perennial, high-marsh species than did geese, which deposited more seeds of early successional, annual, low-marsh

  9. The impact of erosion protection by Stone Dams on Salt-Marsh vegetation on Two Wadden Sea Barrier Islands

    NARCIS (Netherlands)

    Loon-Steensma, van J.M.; Slim, P.A.

    2013-01-01

    This paper describes and quantifies the effect of low stone dams on the extent and composition of salt-marsh habitats on two Dutch Wadden islands: Terschelling and Ameland. The stone dams were built to prevent erosion of the salt-marsh edge. Analyses of a series of aerial photographs taken between

  10. Community Composition of Nitrous Oxide-Related Genes in Salt Marsh Sediments Exposed to Nitrogen Enrichment.

    Science.gov (United States)

    Angell, John H; Peng, Xuefeng; Ji, Qixing; Craick, Ian; Jayakumar, Amal; Kearns, Patrick J; Ward, Bess B; Bowen, Jennifer L

    2018-01-01

    Salt marshes provide many key ecosystem services that have tremendous ecological and economic value. One critical service is the removal of fixed nitrogen from coastal waters, which limits the negative effects of eutrophication resulting from increased nutrient supply. Nutrient enrichment of salt marsh sediments results in higher rates of nitrogen cycling and, commonly, a concurrent increase in the flux of nitrous oxide, an important greenhouse gas. Little is known, however, regarding controls on the microbial communities that contribute to nitrous oxide fluxes in marsh sediments. To address this disconnect, we generated profiles of microbial communities and communities of micro-organisms containing specific nitrogen cycling genes that encode several enzymes ( amoA, norB, nosZ) related to nitrous oxide flux from salt marsh sediments. We hypothesized that communities of microbes responsible for nitrogen transformations will be structured by nitrogen availability. Taxa that respond positively to high nitrogen inputs may be responsible for the elevated rates of nitrogen cycling processes measured in fertilized sediments. Our data show that, with the exception of ammonia-oxidizing archaea, the community composition of organisms involved in the production and consumption of nitrous oxide was altered under nutrient enrichment. These results suggest that previously measured rates of nitrous oxide production and consumption are likely the result of changes in community structure, not simply changes in microbial activity.

  11. Atrotorquata lineata as a proxy for Juncus roemerianus, Part II: Tracking changes in positions of Juncus roemerianus marshes through time by use of the fungal proxy Atrotorquata lineata

    Directory of Open Access Journals (Sweden)

    Marsh Pamela E.

    2016-12-01

    Full Text Available Juncus roemerianus is a species that occurs at the upper reaches of salt water influence in marshes from Delaware to Texas. As such, J. roemerianus is a good marker for sea level, defined for this study as mean highest high water; thus, being able to track its positions over time should enable one to track past changes in relative sea level. In 2006, a palynomorphic fingerprint to identify surface sediment from J. roemerianus marshes was discovered in a South Carolina study (Marsh 2006, Marsh & Cohen 2008. Further study (Marsh & Cohen 2016 showed that one component of this fingerprint, the spore of the fungus Atrotorquata lineata, was so omnipresent in surface sediment from J. roemerianus marshes that the fungus, by itself, can be considered a proxy for J. roemerianus marshes.

  12. Avifauna of Vwaza Marsh Wildlife Reserve, Malawi | Engel | Journal ...

    African Journals Online (AJOL)

    Despite having a well-documented avifauna, some areas of Malawi, such as Vwaza Marsh Wildlife Reserve (986 km²), are still poorly known ornithologically. We spent 12 days in October 2009, before the wet season, and two days in November 2009, after the first rains, documenting the birds of Vwaza. We found six new ...

  13. Carbon Transformations and Source - Sink Dynamics along a River, Marsh, Estuary, Ocean Continuum

    Science.gov (United States)

    Anderson, I. C.; Crosswell, J.; Czapla, K.; Van Dam, B.

    2017-12-01

    Estuaries, the transition zone between land and the coastal ocean, are highly dynamic systems in which carbon sourced from watersheds, marshes, atmosphere, and ocean may be transformed, sequestered, or exported. The net fate of carbon in estuaries, governed by the interactions of biotic and physical drivers varying on spatial and temporal scales, is currently uncertain because of limited observational data. In this study, conducted in a temperate, microtidal, and shallow North Carolina USA estuary, carbon exchanges via river, tributary, and fringing salt marsh, air-water fluxes, sediment C accumulation, and metabolism were monitored over two-years, with sharply different amounts of rainfall. Air-water CO2 fluxes and metabolic variables were simultaneously measured in channel and shoal by conducting high-resolution surveys at dawn, dusk and the following dawn. Marsh CO2 exchanges, sediment C inputs, and lateral exports of DIC and DOC were also measured. Carbon flows between estuary regions and export to the coastal ocean were calculated by quantifying residual transport of DIC and TOC down-estuary as flows were modified by sources, sinks and internal transformations. Variation in metabolic rates, CO2, TOC and DIC exchanges were large when determined for short time and limited spatial scales. However, when scaled to annual and whole estuarine scales, variation tended to decrease because of counteracting metabolic rates and fluxes between channel and shoal or between seasons. Although overall salt marshes accumulated OC, they were a negligible source of DIC and DOC to the estuary, and net inputs of C to the marsh were mainly derived from sediment OC. These results, as observed in other observational studies of estuaries, show that riverine input, light, temperature and metabolism are major controls on carbon cycling. Comparison of our results with other types of estuaries varying in depth, latitude, and nutrification demonstrates large discrepancies underscoring the

  14. Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

    2016-01-01

    Intertidal marshes are alternately exposed and submerged due to periodic ebb and flood tides. The tidal cycle is important in controlling the biogeochemical processes of these ecosystems. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium, remains unexplored in these habitats. Here, we use isotope-tracing and molecular approaches simultaneously to show that both nitrate-reduction activities and associated functional bacterial abundances are enhanced at the sediment-tidal water interface and at the tide-induced groundwater fluctuating layer. This pattern suggests that tidal pumping may sustain dissimilatory nitrate reduction in intertidal zones. The tidal effect is supported further by nutrient profiles, fluctuations in nitrogen components over flood-ebb tidal cycles, and tidal simulation experiments. This study demonstrates the importance of tides in regulating the dynamics of dissimilatory nitrate-reducing pathways and thus provides new insights into the biogeochemical cycles of nitrogen and other elements in intertidal marshes. PMID:26883983

  15. San Pablo Bay Tidal Marsh Enhancement and Water Quality Improvement Project

    Science.gov (United States)

    Information about the SFBWQP San Pablo Bay Tidal Marsh Enhancement and Water Quality Improvement Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  16. Salt marsh as a coastal filter for the oceans: changes in function with experimental increases in nitrogen loading and sea-level rise.

    Directory of Open Access Journals (Sweden)

    Joanna L Nelson

    Full Text Available Coastal salt marshes are among Earth's most productive ecosystems and provide a number of ecosystem services, including interception of watershed-derived nitrogen (N before it reaches nearshore oceans. Nitrogen pollution and climate change are two dominant drivers of global-change impacts on ecosystems, yet their interacting effects at the land-sea interface are poorly understood. We addressed how sea-level rise and anthropogenic N additions affect the salt marsh ecosystem process of nitrogen uptake using a field-based, manipulative experiment. We crossed simulated sea-level change and ammonium-nitrate (NH(4NO(3-addition treatments in a fully factorial design to examine their potentially interacting effects on emergent marsh plants in a central California estuary. We measured above- and belowground biomass and tissue nutrient concentrations seasonally and found that N-addition had a significant, positive effect on a aboveground biomass, b plant tissue N concentrations, c N stock sequestered in plants, and d shoot:root ratios in summer. Relative sea-level rise did not significantly affect biomass, with the exception of the most extreme sea-level-rise simulation, in which all plants died by the summer of the second year. Although there was a strong response to N-addition treatments, salt marsh responses varied by season. Our results suggest that in our site at Coyote Marsh, Elkhorn Slough, coastal salt marsh plants serve as a robust N trap and coastal filter; this function is not saturated by high background annual N inputs from upstream agriculture. However, if the marsh is drowned by rising seas, as in our most extreme sea-level rise treatment, marsh plants will no longer provide the ecosystem service of buffering the coastal ocean from eutrophication.

  17. Aquatic insects of New York salt marsh associated with mosquito larval habitat and their potential utility as bioindicators.

    Science.gov (United States)

    Rochlin, Ilia; Dempsey, Mary E; Iwanejko, Tom; Ninivaggi, Dominick V

    2011-01-01

    The aquatic insect fauna of salt marshes is poorly characterized, with the possible exception of biting Diptera. Aquatic insects play a vital role in salt marsh ecology, and have great potential importance as biological indicators for assessing marsh health. In addition, they may be impacted by measures to control mosquitoes such as changes to the marsh habitat, altered hydrology, or the application of pesticides. Given these concerns, the goals of this study were to conduct the first taxonomic survey of salt marsh aquatic insects on Long Island, New York, USA and to evaluate their utility for non-target pesticide impacts and environmental biomonitoring. A total of 18 species from 11 families and five orders were collected repeatedly during the five month study period. Diptera was the most diverse order with nine species from four families, followed by Coleoptera with four species from two families, Heteroptera with three species from three families, then Odonata and the hexapod Collembola with one species each. Water boatmen, Trichocorixa verticalis Fieber (Heteroptera: Corixidae) and a shore fly, Ephydra subopaca Loew (Diptera: Ephydridae), were the two most commonly encountered species. An additional six species; Anurida maritima Guérin-Méneville (Collembola: Neanuridae), Mesovelia mulsanti White (Heteroptera: Mesovelidae), Enochrus hamiltoni Horn (Coleoptera: Hydrophilidae), Tropisternus quadristriatus Horn (Coleoptera: Hydrophilidae), Dasyhelea pseudocincta Waugh and Wirth (Diptera: Ceratopogonidae), and Brachydeutera argentata Walker (Diptera: Ephydridae), were found regularly. Together with the less common Erythrodiplax berenice Drury (Odonata: Libellulidae), these nine species were identified as the most suitable candidates for pesticide and environmental impact monitoring due to abundance, position in the food chain, and extended seasonal occurrence. This study represents a first step towards developing an insect-based index of biological integrity for

  18. Marshes as "Mountain Tops": Genetic Analyses of the Critically Endangered São Paulo Marsh Antwren (Aves: Thamnophilidae).

    Science.gov (United States)

    de Camargo, Crisley; Gibbs, H Lisle; Costa, Mariellen C; Del-Rio, Glaucia; Silveira, Luís F; Wasko, Adriane P; Francisco, Mercival R

    2015-01-01

    Small populations of endangered species can be impacted by genetic processes such as drift and inbreeding that reduce population viability. As such, conservation genetic analyses that assess population levels of genetic variation and levels of gene flow can provide important information for managing threatened species. The São Paulo Marsh Antwren (Formicivora paludicola) is a recently-described and critically endangered bird from São Paulo State (Brazil) whose total estimated population is around 250-300 individuals, distributed in only 15 isolated marshes around São Paulo metropolitan region. We used microsatellite DNA markers to estimate the population genetic characteristics of the three largest remaining populations of this species all within 60 km of each other. We detected a high and significant genetic structure between all populations (overall FST = 0.103) which is comparable to the highest levels of differentiation ever documented for birds, (e.g., endangered birds found in isolated populations on the tops of African mountains), but also evidence for first-generation immigrants, likely from small local unsampled populations. Effective population sizes were small (between 28.8-99.9 individuals) yet there are high levels of genetic variability within populations and no evidence for inbreeding. Conservation implications of this work are that the high levels of genetic structure suggests that translocations between populations need to be carefully considered in light of possible local adaptation and that remaining populations of these birds should be managed as conservation units that contain both main populations studied here but also small outlying populations which may be a source of immigrants.

  19. Impact of cutting and sheep grazing on ground-active spiders and carabids in intertidal salt marshes (Western France

    Directory of Open Access Journals (Sweden)

    Pétillon, J.

    2007-12-01

    Full Text Available The aims of this study were to characterize spider (Araneae and ground beetle (Coleoptera Carabidae communities in managed (cutting and sheep grazing and non-managed salt marshes and to assess the efficiency of management regimes in these particular ecosystems. The two groups were studied during 2002 in salt marshes of the Mont Saint-Michel Bay (NW France using pitfall traps. By opening soil and vegetation structures cutting and grazing enhanced the abundances of some halophilic species of spiders and ground beetles. Nevertheless, grazing appeared to be too intensive as spider species richness decreased. We discuss the implications of management practices in terms of nature conservation and their application in the particular area of intertidal salt marshes.

  20. Sediment and carbon deposition vary among vegetation assemblages in a coastal salt marsh

    Directory of Open Access Journals (Sweden)

    J. J. Kelleway

    2017-08-01

    Full Text Available Coastal salt marshes are dynamic, intertidal ecosystems that are increasingly being recognised for their contributions to ecosystem services, including carbon (C accumulation and storage. The survival of salt marshes and their capacity to store C under rising sea levels, however, is partially reliant upon sedimentation rates and influenced by a combination of physical and biological factors. In this study, we use several complementary methods to assess short-term (days deposition and medium-term (months accretion dynamics within a single marsh that contains three salt marsh vegetation types common throughout southeastern (SE Australia.We found that surface accretion varies among vegetation assemblages, with medium-term (19 months bulk accretion rates in the upper marsh rush (Juncus assemblage (1.74 ± 0.13 mm yr−1 consistently in excess of estimated local sea-level rise (1.15 mm yr−1. Accretion rates were lower and less consistent in both the succulent (Sarcocornia, 0.78 ± 0.18 mm yr−1 and grass (Sporobolus, 0.88 ± 0.22 mm yr−1 assemblages located lower in the tidal frame. Short-term (6 days experiments showed deposition within Juncus plots to be dominated by autochthonous organic inputs with C deposition rates ranging from 1.14 ± 0.41 mg C cm−2 d−1 (neap tidal period to 2.37 ± 0.44 mg C cm−2 d−1 (spring tidal period, while minerogenic inputs and lower C deposition dominated Sarcocornia (0.10 ± 0.02 to 0.62 ± 0.08 mg C cm−2 d−1 and Sporobolus (0.17 ± 0.04 to 0.40 ± 0.07 mg C cm−2 d−1 assemblages.Elemental (C : N, isotopic (δ13C, mid-infrared (MIR and 13C nuclear magnetic resonance (NMR analyses revealed little difference in either the source or character of materials being deposited among neap versus spring tidal periods. Instead, these analyses point to substantial redistribution of materials within the Sarcocornia and

  1. Macroinvertebrate Prey Availability and Fish Diet Selectivity in Relation to Environmental Variables in Natural and Restoring North San Francisco Bay Tidal Marsh Channels

    OpenAIRE

    Emily R. Howe; Charles A. Simenstad; Jason D. Toft; Jeffrey R. Cordell; Stephen M. Bollens

    2014-01-01

    Tidal marsh wetlands provide important foraging habitat for a variety of estuarine fishes. Prey organisms include benthic–epibenthic macroinvertebrates, neustonic arthropods, and zooplankton. Little is known about the abundance and distribution of interior marsh macroinvertebrate communities in the San Francisco Estuary (estuary). We describe seasonal, regional, and site variation in the composition and abundance of neuston and benthic–epibenthic macroinvertebrates that inhabit tidal marsh ch...

  2. Rapid evolution of a marsh tidal creek network in response to sea level rise.

    Science.gov (United States)

    Hughes, Z. J.; Fitzgerald, D. M.; Mahadevan, A.; Wilson, C. A.; Pennings, S. C.

    2008-12-01

    In the Santee River Delta (SRD), South Carolina, tidal creeks are extending rapidly onto the marsh platform. A time-series of aerial photographs establishes that these channels were initiated in the 1950's and are headward eroding at a rate of 1.9 m /yr. Short-term trends in sea level show an average relative sea level rise (RSLR) of 4.6 mm/yr over a 20-year tide gauge record from nearby Winyah Bay and Charleston Harbor (1975-1995). Longer-term (85-year) records in Charleston suggest a rate of 3.2 mm/yr. RSLR in the SRD is likely even higher as sediment cores reveal that the marsh is predominantly composed of fine-grained sediment, making it highly susceptible to compaction and subsidence. Furthermore, loss in elevation will have been exacerbated by the decrease in sediment supply due to the damming of the Santee River in 1939. The rapid rate of headward erosion indicates that the marsh platform is in disequilibrium; unable to keep pace with RSLR through accretionary processes and responding to an increased volume and frequency of inundation through the extension of the drainage network. The observed tidal creeks show no sinuosity and a distinctive morphology associated with their young age and biological mediation during their evolution. Feedbacks between tidal flow, vegetation and infauna play a strong role in the morphological development of the creeks. The creek heads are characterized by a region denuded of vegetation, the edges of which are densely populated and burrowed by Uca Pugnax (fiddler crab). Crab burrowing destabilizes sediment, destroys rooting and impacts drainage. Measured infiltration rates are three orders of magnitude higher in the burrowed regions than in a control area (1000 ml/min and 0.6 ml/min respectively). Infiltration of oxygenated water enhances decomposition of organic matter and root biomass is reduced within the creek head (marsh=4.3 kg/m3, head=0.6 kg/m3). These processes lead to the removal and collapse of the soils, producing

  3. Effects of grazing management on biodiversity across trophic levels-The importance of livestock species and stocking density in salt marshes

    NARCIS (Netherlands)

    van Klink, Roel; Nolte, Stefanie; Mandema, Freek; Lagendijk, D. D. Georgette; WallisDeVries, Michiel F.; Bakker, Jan P.; Esselink, Peter; Smit, Christian

    2016-01-01

    European coastal salt marshes are important for the conservation of numerous species of specialist plants, invertebrates, breeding and migratory birds. When these marshes are managed for nature conservation purposes, livestock grazing is often used to counter the dominance of the tall grass

  4. Growth of common brackish marsh macrophytes under altered hydrology and salinity regimes

    Science.gov (United States)

    Howard, Rebecca J.; Biagas, Janelda M.; Allain, Larry K.

    2016-01-01

    Coastal marsh plants are increasingly subject to physicochemical stressors under rising sea levels, and the maintenance of marsh ecological functions can depend on the ability of individual species and communities to tolerate or adapt to altered conditions. We conducted a greenhouse experiment to identify hydrology and salinity effects on growth of three common brackish marsh macrophytes of coastal Florida, USA: Distichlis spicata, Juncus roemerianus, and Spartina bakeri. The species were potted as monocultures and exposed to three salinities (0, 15, or 28 psu) and two hydrologic conditions (saturated, tidal) over 22 months. Final stem density of J. roemerianus and S. bakeri did not differ among treatments. In D. spicata, however, stem density was lowest at 28 psu and lower in tidal compared to saturated conditions. Mean stem height of all species was lowest at 28 psu. Aboveground biomass of J. roemerianus was not affected by the treatments, but in D. spicata andS. bakeri it was lowest at 28 psu. Results indicated that J. roemerianus was the most adaptable species and may, therefore, be more resilient to climate-change driven stressors. However, plant-plant interactions such as interspecific competition and facilitation can alter the response of individual species to environmental factors.

  5. Bottom-up and top-down human impacts interact to affect a protected coastal Chilean marsh.

    Science.gov (United States)

    Fariña, José M; He, Qiang; Silliman, Brian R; Bertness, Mark D

    2016-03-01

    Many ecosystems, even in protected areas, experience multiple anthropogenic impacts. While anthropogenic modification of bottom-up (e.g., eutrophication) and top-down (e.g., livestock grazing) forcing often co-occurs, whether these factors counteract or have additive or synergistic effects on ecosystems is poorly understood. In a Chilean bio-reserve, we examined the interactive impacts of eutrophication and illegal livestock grazing on plant growth with a 4-yr fertilization by cattle exclusion experiment. Cattle grazing generally decreased plant biomass, but had synergistic, additive, and antagonistic interactions with fertilization in the low, middle, and high marsh zones, respectively. In the low marsh, fertilization increased plant biomass by 112%, cattle grazing decreased it by 96%, and together they decreased plant biomass by 77%. In the middle marsh, fertilization increased plant biomass by 47%, cattle grazing decreased it by 37%, and together they did not affect plant biomass. In the high marsh, fertilization and cattle grazing decreased plant biomass by 81% and 92%, respectively, but together they increased plant biomass by 42%. These interactions were also found to be species specific. Different responses of plants to fertilization and cattle grazing were likely responsible for these variable interactions. Thus, common bottom-up and top-down human impacts can interact in different ways to affect communities even within a single ecosystem. Incorporating this knowledge into conservation actions will improve ecosystem management in a time when ecosystems are increasingly challenged by multiple interacting human impacts.

  6. Peat Archives in the Hudson River Estuary… Marsh Formation, Carbon Storage and Release, and Resilience

    Science.gov (United States)

    Peteet, D. M.; Corbett, E. J.; Nichols, J. E.; Kenna, T. C.; Chang, C.

    2017-12-01

    We target deep peat stores (at least 8 meters) of carbon in the lower Hudson Estuary, which formed as the glacial fjord became an estuary with mid-Holocene sea level rise. These deep marshes play an extremely important role in the estuary health and stability in a changing climate. Never before have we faced the threats to coastal marshes that we are facing today, and the resulting sedimentation rates, inorganic/organic component histories, pollen, macrofossil, isotopic, and XRF data reveal critical information about past vegetation and climate change. Long-term shifts in organic/inorganic storage appear to be linked to drought, as watershed erosion results in more sand, silt and clay in the marshes. Climatic shifts often result in regional watershed shifts in vegetation, both locally and regionally. Understanding how these marshes are linked to human impact (disturbance, invasive species, higher nitrogen, heavy metal pollution, dams) over the last four centuries is critical to providing management of these key ecosystems, and their preservation as sea level rises. Quantification of processes that cause carbon degradation and release from these wetlands to the estuary is also key to this investigation. Peat loss would contribute to heavy metal pollution in the estuary as well as carbon loss. Young investigators from secondary schools in New York City participated in much of the fieldwork as part of the NASA/GISS NYC Research Initiative and the LDEO Secondary School Field Research Carbon Team.

  7. Mechanism of removal and retention of heavy metals from the acid mine drainage to coastal wetland in the Patagonian marsh.

    Science.gov (United States)

    Idaszkin, Yanina L; Carol, Eleonora; María Del Pilar, Alvarez

    2017-09-01

    The attenuation of the acid mine drainage is one of the most important environmental challenges facing the mining industry worldwide. Mining waste deposits from an ancient metallurgical extraction of heavy metals were found near to the San Antonio marsh in Patagonia. The aim of this work was to determinate which mechanisms regulate the mobilization and retention of metals by acid drainage. A geological and geomorphological survey was carried out and samples from the mining waste deposits and the marsh were collected to determine soil texture, Eh pH, organic matter, Cu, Pb, Zn and Fe content, and soil mineralogical composition. Metals in marsh plants were determined in above- and below-ground structures. In the mining waste deposits polymetallic sulphides were recognized where the oxidation and formation of oxy-hydroxides and sulphates of Fe, Cu, Pb and Zn occurs. Then, by the alteration of those minerals, the metals enter in solution and are mobilized with the surface drainage towards the marsh where adsorption in the soils fine fraction and organic matter and/or by plants occurs. Locally, in the mining waste deposits, the precipitation/dissolution of Cu, Pb, and Zn sulphates take place in small centripetal drainage basins. In topographically lower portions of the marsh desorption and removal of metals by tidal flow could also be happen. The results allow to concluding that the marsh adjacent to the mining waste deposits is a geochemically active environment that naturally mitigates the contamination caused by acid drainage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Nuclear power plant diagnostics study at the Midland training simulator

    International Nuclear Information System (INIS)

    Reifman, J.; Rank, P.; Lee, J.C.

    1991-01-01

    Training simulators provide a real world environment for testing advanced diagnostic and control systems as an aid to nuclear power plant operators. The simulators not only duplicate the hardware din the actual control room, allowing for analysis of man-machine interface, but also represent the dynamic behavior of the reference plant in real-time, in a realistic manner. Training simulators provide the means to representing the reference plant operations in a wide range of operation conditions including off-normal and emergency conditions. Transient events with very low probability of occurrence can then be represented and used to test the capabilities of advanced diagnostic and control systems. For these reasons, full-scope operator training simulators have been used as a test bed for a number of advanced diagnostic concepts. The University of Michigan and Consumers Power Company have been collaborating in a program devoted to the development and study of advanced concepts for automatic diagnostics and control of nuclear power plants. The program has been focused on the use of the full-scope operator training Midland Nuclear Power Plant Unit 2 (MNP-2) Simulator for development, testing, and verification of advanced diagnostics concepts. In their current efforts, the authors have developed two artificial intelligent (AI) diagnostic concepts that have been applied to the MNP-2 Simulator: the systematic generation and updating of a rule-based knowledge system for nuclear power plant diagnostics and a nonlinear parameter estimation algorithm called the simulation filter. The simulation filter algorithm is used with the MNP-2 Simulator to improve the simulation of the Three Mile Island Unit 2 (TMI-2) accident. 11 refs., 4 figs

  9. Enrichment of marsh soils with heavy metals by effect of anthropic pollution

    International Nuclear Information System (INIS)

    Vega, Flora A.; Covelo, Emma F.; Cerqueira, Beatriz; Andrade, Maria Luisa

    2009-01-01

    The impact of waste disposal on marsh soils was assessed in topsoil samples collected at eight randomly selected points in the salt marsh in Ramallosa (Pontevedra, Spain) at 4-month intervals for 2 years. Polluted soil samples were characterized in physico-chemical terms and their heavy metal contents determined by comparison with control, unpolluted samples. The results revealed a marked effect of waste discharges on the soils in the area, which have low contents in heavy metals under normal environmental conditions. In fact, the studied soils were found to contain substantial amounts of total and DTPA-extractable Cd, Cu, Pb and Zn. Based on the relationship of the redox potential with the DTPA-extractable Cd, Cu, Pb, and Zn contents of the soils, strongly reductive conditions raised the total contents in these elements by effect of their remaining in the soils as precipitated sulphides. Such contents, however, decreased as oxidative conditions gradually prevailed. The contents in DTPA-extractable metals increased with increasing Eh through the release of the metals in ionic form to the soil solution under oxidative conditions. The contents in heavy metals concentrating in the polluted soils were several times higher than those in the control soils (viz. 2 vs. 6 for Cd, 4 vs. 6 for Cu, 4 vs. 20 for Pb, and 2 vs. 15 for Zn, all in mg kg -1 ). This can be expected to influence the amounts of available heavy metals present in the soils, and hence the environmental quality of the area, in the near future. Based on its geoaccumulation index (Class ≥3 for Cd and Cu, and 1-4 for Pb and Zn), the Ramallosa marsh is highly polluted with Cd and moderately to highly polluted with Cu, Pb and Zn. The enrichment factors obtained confirm that the salt marsh is highly polluted (especially with Cd) as the primary result of anthropic activity.

  10. Delineation of ground water potential zones using GIS and remote sensing - A case study from midland region of Vamanapuram river basin, Kerala, India

    Science.gov (United States)

    Prasad, Geena; Vinod P., G.; John, Shaleena Elizabeth

    2018-04-01

    In a highly rugged terrain, shielded by hard crystalline rocks like that of Kerala, locating potential zones of groundwater is found to be an unenviable task. Remote sensing and Geographical information system technologies have been attempted widely to delineate the potential regions in such terrain. Geographical information system tool has been used for delineation of groundwater prospect zones in midland physiographic zone (30-200m) of Vamanapuram river basin. The terrain variables are generated using satellite imageries, SRTM DEM data of 30m resolution and SOI toposheets. The groundwater prospect zones were delineated through the integration of the reclassified raster map layers of geomorphology, slope percent, geology, land use / land cover and soil texture using the weighted overlay analysis in the GIS platform. The groundwater prospects in the study area were grouped into five classes and their distribution are; `very high/high' (8.79%), `moderate' (39.08%), and `very low / low' (52.01%). The study result of the area has been validated with water level data of dug wells and bore wells of the area. The spatial distribution map of the water level of the region is overlaid on groundwater prospect map and shows a positive correlation i.e., the water level at shallow depth in higher prospect zones and at deeper depth in poor to very poor zones. The Groundwater prospect map of midland region of Vamanapuram river basin can be used as base level information which can be further investigated with geophysical methods to locate potential well sites for the execution of water supply schemes.

  11. Reintroduction of salt marsh vegetation and phosphorus fertilisation improve plant colonisation on seawater-contaminated cutover bogs

    Directory of Open Access Journals (Sweden)

    C. Emond

    2016-07-01

    Full Text Available Coastal bogs that are used for peat extraction are prone to contamination by seawater during storm events. Once contaminated, they remain mostly bare because of the combination of high salinity, low pH, high water table and low nutrient availability. The goal of this research was to investigate how plant colonisation at salt-contaminated bogs can be accelerated, in order to prevent erosion and fluvial export of the peat. At two seawater-contaminated bogs, we tested the application of rock phosphate and dolomitic lime in combination with five plant introduction treatments: transplantation of Carex paleacea; transplantation of Spartina pectinata; transfer of salt marsh diaspores in July; transfer of salt marsh diaspores in August; and no treatment (control. The effects of different doses of lime on the growth of C. paleacea and S. pectinata were also investigated in a greenhouse experiment. In the field, phosphorus fertilisation improved plant growth. Transplantation of C. paleacea resulted in the highest plant colonisation, whereas salt marsh diaspore transfer led to the highest species diversity. Lime applications did not improve plant establishment in either the field or the greenhouse. To promote revegetation of seawater-contaminated cutover bogs, adding P is an asset, Carex paleacea is a good species to transplant, and the transfer of salt marsh diaspores improves plant diversity.

  12. Plant distributions along salinity and tidal gradients in Oregon tidal marshes

    Science.gov (United States)

    Accurately modeling climate change effects on tidal marshes in the Pacific Northwest requires understanding how plant assemblages and species are presently distributed along gradients of salinity and tidal inundation. We outline on-going field efforts by the EPA and USGS to dete...

  13. Functionality of Root-Associated Bacteria along a Salt Marsh Primary Succession

    NARCIS (Netherlands)

    Wang, Miao; Li, Erqin; Liu, Chen; Jousset, Alexandre|info:eu-repo/dai/nl/370632656; Salles, Joana Falcão

    2017-01-01

    Plant-associated bacteria are known for their high functional trait diversity, from which many are likely to play a role in primary and secondary succession, facilitating plant establishment in suboptimal soils conditions. Here we used an undisturbed salt marsh chronosequence that represents over

  14. A dynamic nitrogen budget model of a Pacific Northwest salt marsh

    Science.gov (United States)

    The role of salt marshes as either nitrogen sinks or sources in relation to their adjacent estuaries has been a focus of ecosystem service research for many decades. The complex hydrology of these systems is driven by tides, upland surface runoff, precipitation, evapotranspirati...

  15. Functionality of root-associated bacteria along a salt marsh primary succession

    NARCIS (Netherlands)

    Wang, Miao; Li, Erqin; Liu, Chen; Jousset, Alexandre; Salles, Joana F.

    2017-01-01

    Plant-associated bacteria are known for their high functional trait diversity, from which many are likely to play a role in primary and secondary succession, facilitating plant establishment in suboptimal soils conditions. Here we used an undisturbed salt marsh chronosequence that represents over

  16. Distribution and Invasion Potential of Limonium ramosissimum subsp. provinciale in San Francisco Estuary Salt Marshes

    Directory of Open Access Journals (Sweden)

    Gavin Archbald

    2014-06-01

    Full Text Available Non-native sea lavenders (Limonium spp. are invasive in salt marshes of southern California and were first documented in the San Francisco Estuary (the estuary in 2007. In this study, we mapped distributions of L. ramosissimum subsp. provinciale (LIRA and L. duriusculum within the estuary and investigated how the invasion potential of the more common species, LIRA, varies with elevation and edaphic conditions. We contacted colleagues and conducted field searches to find and then map sea lavender populations. In addition, we measured LIRA’s elevational range at three salt marshes. Across this range we measured (1 soil properties: salinity, moisture, bulk density, and texture; and (2 indicators of invasion potential: LIRA size, seed production, percent cover, spread (over 1 year, recruitment, and competition with native halophytes (over 6 months. We found LIRA in 15,144 m2 of upper salt marsh habitat in central and south San Francisco bays and L. duriusculum in 511 m2 in Richardson and San Pablo bays. LIRA was distributed from mean high water (MHW to 0.42 m above mean higher high water (MHHW. In both spring and summer, soil moisture and salinity were lowest at higher elevations within LIRA’s range, which corresponded with greater rosette size, inflorescence and seed production (up to 17,400 seeds per plant, percent cover, and recruitment. LIRA cover increased on average by 11% in 1 year across marshes and elevations. Cover of the native halophytes Salicornia pacifica, Jaumea carnosa, and Distichlis spicata declined significantly at all elevations if LIRA were present in plots (over a 6-month, fall–winter period. Results suggest LIRA’s invasion potential is highest above MHHW where salinity and moisture are lower, but that LIRA competes with native plants from MHW to above MHHW. We recommend removal efforts with emphasis on the salt marsh-terrestrial ecotone where LIRA seed output is highest.

  17. Development of a multimetric index for integrated assessment of salt marsh ecosystem condition

    Science.gov (United States)

    Nagel, Jessica L.; Neckles, Hilary A.; Guntenspergen, Glenn R.; Rocks, Erika N.; Schoolmaster, Donald; Grace, James B.; Skidds, Dennis; Stevens, Sara

    2018-01-01

    Tools for assessing and communicating salt marsh condition are essential to guide decisions aimed at maintaining or restoring ecosystem integrity and services. Multimetric indices (MMIs) are increasingly used to provide integrated assessments of ecosystem condition. We employed a theory-based approach that considers the multivariate relationship of metrics with human disturbance to construct a salt marsh MMI for five National Parks in the northeastern USA. We quantified the degree of human disturbance for each marsh using the first principal component score from a principal components analysis of physical, chemical, and land use stressors. We then applied a metric selection algorithm to different combinations of about 45 vegetation and nekton metrics (e.g., species abundance, species richness, and ecological and functional classifications) derived from multi-year monitoring data. While MMIs derived from nekton or vegetation metrics alone were strongly correlated with human disturbance (r values from −0.80 to −0.93), an MMI derived from both vegetation and nekton metrics yielded an exceptionally strong correlation with disturbance (r = −0.96). Individual MMIs included from one to five metrics. The metric-assembly algorithm yielded parsimonious MMIs that exhibit the greatest possible correlations with disturbance in a way that is objective, efficient, and reproducible.

  18. Defining restoration targets for water depth and salinity in wind-dominated Spartina patens (Ait.) Muhl. coastal marshes

    Science.gov (United States)

    Nyman, J.A.; LaPeyre, Megan K.; Caldwell, Andral W.; Piazza, Sarai C.; Thom, C.; Winslow, C.

    2009-01-01

    Coastal wetlands provide valued ecosystem functions but the sustainability of those functions often is threatened by artificial hydrologic conditions. It is widely recognized that increased flooding and salinity can stress emergent plants, but there are few measurements to guide restoration, management, and mitigation. Marsh flooding can be estimated over large areas with few data where winds have little effect on water levels, but quantifying flooding requires hourly measurements over long time periods where tides are wind-dominated such as the northern Gulf of Mexico. Estimating salinity of flood water requires direct daily measurements because coastal marshes are characterized by dynamic salinity gradients. We analyzed 399,772 hourly observations of water depth and 521,561 hourly observations of water salinity from 14 sites in Louisiana coastal marshes dominated by Spartina patens (Ait.) Muhl. Unlike predicted water levels, observed water levels varied monthly and annually. We attributed those observed variations to variations in river runoff and winds. In stable marshes with slow wetland loss rates, we found that marsh elevation averaged 1 cm above mean high water, 15 cm above mean water, and 32 cm above mean low water levels. Water salinity averaged 3.7 ppt during April, May, and June, and 5.4 ppt during July, August, and September. The daily, seasonal, and annual variation in water levels and salinity that were evident would support the contention that such variation be retained when designing and operating coastal wetland management and restoration projects. Our findings might be of interest to scientists, engineers, and managers involved in restoration, management, and restoration in other regions where S. patens or similar species are common but local data are unavailable.

  19. Spatial patterns in salt marsh porewater dissolved organic matter over a spring-neap tidal cycle: insight to the impact of hydrodynamics on lateral carbon fluxes

    Science.gov (United States)

    Guimond, J. A.; Yu, X.; Duque, C.; Michael, H. A.

    2016-12-01

    Salt marshes are a hydrologically complex ecosystem. Tides deliver saline surface water to salt marshes via tidal creeks, and freshwater is introduced through lateral groundwater flow and vertical infiltration from precipitation. Locally, sediment heterogeneity, tides, weather, and topography introduce spatial and temporal complexities in groundwater-surface water interactions, which, in turn, can have a large impact on salt marsh biogeochemistry and the lateral fluxes of nutrients and carbon between the marsh platform and tidal creek. In this study, we investigate spatial patterns of porewater fluorescent dissolved organic matter (fDOM) and redox potential over a spring-neap tidal cycle in a mid-latitude tidal salt marsh in Dover, Delaware. Porewater samplers were used in conjunction with a peristaltic pump and YSI EXO Sonde to measure porewater fDOM, electrical conductivity, redox potential and pH from 0.5, 1.0, 1.5, 2.0, and 2.3 meters deep, as well as surface water from the creek and marsh platform. Eh was also measured continuously every 15 minutes with multi-level in-situ redox sensors at 0, 3, and 5m from the tidal creek, and water level and salinity were measured every 15 minutes continuously in 6 wells equipped with data loggers. Preliminary analyses indicate porewater salinity is dependent on the slope of the marsh platform, the elevation of the sample location, and the distance from a tidal creek. Near-creek redox analyses show tidal oscillations up to 300 mV; redox oscillations in the marsh interior show longer timescale changes. The observed redox oscillations coincide with the water level fluctuations at these locations. Therefore, lateral transport of carbon is determined by both hydrologic flow and biogeochemical processes. Results from this study provide insight into the timescales over which salt marsh hydrology impacts porewater biogeochemistry and the mechanisms controlling regional carbon cycling.

  20. Use of antimicrobial resistance information and prescribing guidance for management of urinary tract infections: survey of general practitioners in the West Midlands.

    Science.gov (United States)

    Ironmonger, Dean; Edeghere, Obaghe; Gossain, Savita; Hawkey, Peter M

    2016-05-24

    There is a marked variation in both antibiotic prescribing practice and urine sampling rates for diagnostic microbiology across general practices in England. To help understand factors driving this variation, we undertook a survey in 2012/13 to determine sampling protocols and antibiotic formularies used by general practitioners (GPs) for managing urinary tract infections (UTIs) in the West Midlands region of England. Cross-sectional survey of all eligible general practices in the West Midlands region of England undertaken in November 2012. GPs were invited to complete an online survey questionnaire to gather information on policies used within the practice for urine sampling for microbiological examination, and the source of antibiotic formularies used to guide treatment of UTIs. The questionnaire also gathered information on how they would manage five hypothetical clinical scenarios encountered in the community. The response rate was 11.3 % (409/3635 GPs), equivalent to a practice response rate of 26 % (248/950). Only 50 % of GPs reported having a practice policy for urine sampling. Although there was good agreement from GPs regarding collecting specimens in scenarios symbolising treatment failure (98 %), UTI in an adult male (98 %) and asymptomatic UTI in pregnancy (97 %), there was variation in GPs requesting a specimen for the scenarios involving a suspected uncomplicated urinary tract infection (UTI) and an asymptomatic catheterised elderly patient; with 40 and 38 % respectively indicating they would collect a specimen for microbiological examination. Standardised evidence based clinical management policies and antibiotic formularies for GPs should be readily available. This will promote the rational use of diagnostic microbiology services, improve antimicrobial stewardship and aid the interpretation of ongoing antimicrobial resistance surveillance.

  1. Marsh plant response to metals: Exudation of aliphatic low molecular weight organic acids (ALMWOAs)

    Science.gov (United States)

    Rocha, A. Cristina S.; Almeida, C. Marisa R.; Basto, M. Clara P.; Vasconcelos, M. Teresa S. D.

    2016-03-01

    Metal exposure is known to induce the production and secretion of substances, such as aliphatic low molecular weight organic acids (ALMWOAs), into the rhizosphere by plant roots. Knowledge on this matter is extensive for soil plants but still considerably scarce regarding marsh plants roots adapted to high salinity media. Phragmites australis and Halimione portulacoides, two marsh plants commonly distributed in European estuarine salt marshes, were used to assess the response of roots of both species, in terms of ALMWOAs exudation, to Cu, Ni and Cd exposure (isolated and in mixture since in natural environment, they are exposed to mixture of metals). As previous studies were carried out in unrealistic and synthetic media, here a more natural medium was selected. Therefore, in vitro experiments were carried out, with specimens of both marsh plants, and in freshwater contaminated with two different Cu, Ni and Cd concentrations (individual metal and in mixture). Both marsh plants were capable of liberating ALMWOAs into the surrounding medium. Oxalic, citric and maleic acids were found in P. australis root exudate solutions and oxalic and maleic acids in H. portulacoides root exudate solutions. ALMWOA liberation by both plants was plant species and metal-dependent. For instance, Cu affected the exudation of oxalic acid by H. portulacoides and of oxalic and citric acids by P. australis roots. In contrast, Ni and Cd did not stimulate any specific response. Regarding the combination of all metals, H. portulacoides showed a similar response to that observed for Cu individually. However, in the P. australis case, at high metal concentration mixture, a synergetic effect led to the increase of oxalic acid levels in root exudate solution and to a decrease of citric acid liberation. A correlation between ALMWOAs exudation and metal accumulation could not be established. P. australis and H. portulacoides are considered suitable metal phytoremediators of estuarine impacted areas

  2. Long-term organic carbon sequestration in tidal marsh sediments is dominated by old-aged allochthonous inputs in a macrotidal estuary.

    Science.gov (United States)

    Van de Broek, Marijn; Vandendriessche, Caroline; Poppelmonde, Dries; Merckx, Roel; Temmerman, Stijn; Govers, Gerard

    2018-02-12

    Tidal marshes are vegetated coastal ecosystems that are often considered as hotspots of atmospheric CO 2 sequestration. Although large amounts of organic carbon (OC) are indeed being deposited on tidal marshes, there is no direct link between high OC deposition rates and high OC sequestration rates due to two main reasons. First, the deposited OC may become rapidly decomposed once it is buried and, second, a significant part of preserved OC may be allochthonous OC that has been sequestered elsewhere. In this study we aimed to identify the mechanisms controlling long-term OC sequestration in tidal marsh sediments along an estuarine salinity gradient (Scheldt estuary, Belgium and the Netherlands). Analyses of deposited sediments have shown that OC deposited during tidal inundations is up to millennia old. This allochthonous OC is the main component of OC that is effectively preserved in these sediments, as indicated by the low radiocarbon content of buried OC. Furthermore, OC fractionation showed that autochthonous OC is decomposed on a decadal timescale in saltmarsh sediments, while in freshwater marsh sediments locally produced biomass is more efficiently preserved after burial. Our results show that long-term OC sequestration is decoupled from local biomass production in the studied tidal marsh sediments. This implies that OC sequestration rates are greatly overestimated when they are calculated based on short-term OC deposition rates, which are controlled by labile autochthonous OC inputs. Moreover, as allochthonous OC is not sequestered in-situ, it does not contribute to active atmospheric CO 2 sequestration in these ecosystems. A correct assessment of the contribution of allochthonous OC to the total sedimentary OC stock in tidal marsh sediments as well as a correct understanding of the long-term fate of locally produced OC are both necessary to avoid overestimations of the rate of in-situ atmospheric CO 2 sequestration in tidal marsh sediments. © 2018 John

  3. Soil salinity data from Bayou Dupont and flanking marshes, New Orleans, LA, 2015-09-16 to 2016-03-30 (NCEI Accession 0151633)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The project restored both structural and habitat functions of Bayou Dupont and flanking marshes. The project created and nourished marsh and restored a ridge on the...

  4. Effects of winter marsh burning on abundance and nesting activity of Louisiana seaside sparrows in the Gulf Coast Chenier Plain

    Science.gov (United States)

    Gabrey, S.W.; Afton, A.D.

    2000-01-01

    Louisiana Seaside Sparrows (Ammodramus maritimus fisheri) breed and winter exclusively in brackish and saline marshes along the northern Gulf of Mexico. Many Gulf Coast marshes, particularly in the Chenier Plain of southwestern Louisiana and southeastern Texas, are burned intentionally in fall or winter as part of waterfowl management programs. Fire reportedly has negatively affected two Seaside Sparrow subspecies (A. m. nigrescens and A. m. mirabilis) in Florida, but there is no published information regarding effects of fire on A. m. fisheri. We compared abundance of territorial male Louisiana Seaside Sparrows, number of nesting activity indicators, and vegetation structure in paired burned and unburned plots in Chenier Plain marshes in southwestern Louisiana during the 1996 breeding season (April-July) before experimental winter burns (January 1997) and again during two breeding seasons post-burn (1997-1998). We found that abundance of male sparrows decreased in burned plots during the first breeding season post-burn, but was higher than that of unburned plots during the second breeding season post-burn. Indicators of nesting activity showed a similar but non-significant pattern in response to burning. Sparrow abundance and nesting activity seemingly are linked to dead vegetation cover, which was lower in burned plots during the first breeding season post-burn, but did not differ from that in unburned plots during the second breeding season post-burn. We recommend that marsh management plans in the Gulf Coast Chenier Plain integrate waterfowl and Seaside Sparrow management by maintaining a mosaic of burned and unburned marshes and allowing vegetation to recover for at least two growing seasons before reburning a marsh.

  5. The role of succulent halophytes in the water balance of salt marsh rodents.

    Science.gov (United States)

    Coulombe, Harry N

    1970-09-01

    The role of succulent halophytes in the water balance and ecology of salt marsh rodents is dependent upon an evaluation of the composition of the available sources and the physiological properties of their potential consumers. Studies of the osmotic properties of succulent halophytes from southern California coastal salt marshes are presented, together with experiments regarding the utilization of Common Pickleweed (Salicornia virginica L.) by indigenous populations of cricetid rodents (harvest mouse Reithrodontomys megalotis limicola Von Bloecker, and meadow-mouse Microtus californicus stephensi Von Bloecker). These data are discussed in relation to other available information concerning the ecology of coastal salt marshes, particularly in western North America.Extruded sap of Common Pickleweed was found to have a mean total osmotic pressure (TOP) of 1,450 mOsm/liter, with an average chloride ion content of 876 mEq/liter (about 70% of the TOP). A related species, Salicornia subterminale, had a slightly lower TOP (1,300 mOsm/liter), of which about 29% was accounted for by chloride ion concentration. Sea Blight (Suaeda fruticosa) was the only species in which the TOP correlated with the distance from the tide level; sap TOP increased away from the lagoon's edge. In both Sea Blight and Common Pickle weed, TOP was not directly related to chloride content, indicating the importance of other osmotically active solutes.Harvest mice were placed on three experimental regimes: 1) millet seeds only, 2) pickleweed only, and 3) pickleweed and millet seed. Meadow mice were tested on the last regime only. Harvest mice survived best on a strict millet seed diet; when Salicornia was consumed to a detectable extent, the mice did not survive. Meadow mice, however, could survive using Salicornia as a dietary source in conjunction with seeds. Kidney electrolyte concentrating abilities indicated that harvest mice should be able to utilize pickleweed; this was not confirmed in my

  6. Consumer trait variation influences tritrophic interactions in salt marsh communities.

    Science.gov (United States)

    Hughes, Anne Randall; Hanley, Torrance C; Orozco, Nohelia P; Zerebecki, Robyn A

    2015-07-01

    The importance of intraspecific variation has emerged as a key question in community ecology, helping to bridge the gap between ecology and evolution. Although much of this work has focused on plant species, recent syntheses have highlighted the prevalence and potential importance of morphological, behavioral, and life history variation within animals for ecological and evolutionary processes. Many small-bodied consumers live on the plant that they consume, often resulting in host plant-associated trait variation within and across consumer species. Given the central position of consumer species within tritrophic food webs, such consumer trait variation may play a particularly important role in mediating trophic dynamics, including trophic cascades. In this study, we used a series of field surveys and laboratory experiments to document intraspecific trait variation in a key consumer species, the marsh periwinkle Littoraria irrorata, based on its host plant species (Spartina alterniflora or Juncus roemerianus) in a mixed species assemblage. We then conducted a 12-week mesocosm experiment to examine the effects of Littoraria trait variation on plant community structure and dynamics in a tritrophic salt marsh food web. Littoraria from different host plant species varied across a suite of morphological and behavioral traits. These consumer trait differences interacted with plant community composition and predator presence to affect overall plant stem height, as well as differentially alter the density and biomass of the two key plant species in this system. Whether due to genetic differences or phenotypic plasticity, trait differences between consumer types had significant ecological consequences for the tritrophic marsh food web over seasonal time scales. By altering the cascading effects of the top predator on plant community structure and dynamics, consumer differences may generate a feedback over longer time scales, which in turn influences the degree of trait

  7. Changes in standing stocks and fluxes of carbon due to salinization: tidal freshwater wetland forest retreat to marsh

    Science.gov (United States)

    Krauss, K.; Noe, G. B.; Duberstein, J. A.; Conner, W. H.; Stagg, C. L.; Jones, M.; Bernhardt, C. E.; Cormier, N.

    2017-12-01

    Assessments of organic carbon (C) standing stocks and fluxes as wetland ecosystems transition from tidally influenced freshwater forested wetlands to low-salinity marshes are not typically included in "blue carbon" accounting. However, these ecosystems have the potential to store and convey large quantities of C. Here, we report on data collected from eight riverine sites along salinity and hydro-edaphic gradients in South Carolina and Georgia to provide the first complete estimates of C storage, flux, and burial, including estimation of C export to aquatic environments, in tidal freshwater forested wetlands undergoing transition to oligohaline marsh. Total standing stocks of C ranged from 280 to 891 Mg C/ha along both rivers but with no consistent trend in standing stock shifts along salinity gradients between the two rivers. Soil C standing stocks were most variable among sites. Furthermore, we assessed input (litterfall, woody growth, herbaceous growth, root growth and surface sediment C accretion) in comparison with output (surface litter decomposition, root decomposition and gaseous C) fluxes over periods ranging from 2 to 11 years. C sequestration from mass balance calculations ranged from 103 to 728 g C/m2/year among sites, with generally greater C sequestration on sites with prominent salinity-mediated conversion to oligohaline marsh. Dissolved C export was estimated as the difference between C sequestration and soil C burial using 14C dating of cores, and ranged from 144 to 404 g C/m2/year, representing a large amount of C export to feed aquatic biogeochemical transformations and secondary productivity. Along with C accounting, these sites also differed in how N and P were mineralized in soils, with considerable N mineralization on salinity-stressed (2.4-4.3 parts per thousand) forested sites with newly encroached marsh plants and considerable P mineralization on slightly higher salinity marshes. In all, C storage from tidal freshwater forested wetlands

  8. Temperate mangrove and salt marsh sediments are a small methane and nitrous oxide source but important carbon store

    Science.gov (United States)

    Livesley, Stephen J.; Andrusiak, Sascha M.

    2012-01-01

    Tidal saline wetlands (TSW), such as mangrove and salt marsh systems, provide many valuable ecosystem services, but continue to suffer disturbance, degradation and deforestation. Tropical mangroves perform a critical role in the exchange and storage of terrestrial-marine carbon but can function as a source of methane (CH 4) and nitrous oxide (N 2O). However, little is known of biogeochemical processes in temperate mangrove and salt marsh systems in the southern hemisphere. In this study, the soil/sediment exchange of CO 2, CH 4 and N 2O was measured seasonally along a natural transition from melaleuca woodland, salt marsh and into mangroves along the Mornington Peninsula edge of Westernport Bay, Victoria, Australia. Soil/sediment physiochemical properties and sediment C density were measured concurrently. The melaleuca woodland soil was a constant CH 4 sink of approximately -25 μg C m -2 h -1 but along the transect this rapidly switched to a weak CH 4 source (mangrove sediments where emissions of up to 375 μg C m -2 h -1 were measured in summer. Sediment CH 4 exchange correlated with salinity, pneumatophore number and the redox potential of sediment water at depth. All three ecosystems were a small N 2O source of ecosystem and season along with soil temperature and salinity. Sediment C density was significantly greater in the salt marsh than the mangrove. Salt marsh sediment C density was 168 Mg C ha -1 which is comparable with that measured globally, whereas the mangrove sediment C density of 145 Mg C ha -1 is among the lowest reported. Contrary to global patterns in terrestrial soil C content and salt marsh sediment C content, data from our study indicate that mangrove sediments from a cooler, drier temperate latitude may store less C than mangroves in warmer and wetter tropical latitudes. Understanding both C storage and the greenhouse gas balance of TSWs will help us to better value these vulnerable ecosystems and manage them accordingly.

  9. Effects of grazing management on biodiversity across trophic levels – The importance of livestock species and stocking density in salt marshes

    NARCIS (Netherlands)

    Klink, van Roel; Nolte, Stefanie; Mandema, Freek S.; Lagendijk, D.D.G.; Wallis de Vries, Michiel; Bakker, Jan P.; Esselink, Peter; Smit, Christian

    2016-01-01

    European coastal salt marshes are important for the conservation of numerous species of specialist plants, invertebrates, breeding and migratory birds. When these marshes are managed for nature conservation purposes, livestock grazing is often used to counter the dominance of the tall grass

  10. Nitrogen assimilation and short term retention in a nutrient-rich tidal freshwater marsh – a whole ecosystem 15N enrichment study

    Directory of Open Access Journals (Sweden)

    B. Gribsholt

    2007-01-01

    Full Text Available An intact tidal freshwater marsh system (3477 m2 was labelled by adding 15N-ammonium as a tracer to the flood water inundating the ecosystem. The appearance and retention of 15N-label in different marsh components (leaves, roots, sediment, leaf litter and invertebrate fauna was followed over 15 days. This allowed us to elucidate the direct assimilation and dependence on creek-water nitrogen on a relatively short term and provided an unbiased assessment of the relative importance of the various compartments within the ecosystem. Two separate experiments were conducted, one in spring/early summer (May 2002 when plants were young and building up biomass; the other in late summer (September 2003 when macrophytes were in a flowering or early senescent state. Nitrogen assimilation rate (per hour inundated was >3 times faster in May compared to September. On both occasions, however, the results clearly revealed that the less conspicuous compartments such as leaf litter and ruderal vegetations are more important in nitrogen uptake and retention than the prominent reed (Phragmites australis meadows. Moreover, short-term nitrogen retention in these nutrient rich marshes occurs mainly via microbial pathways associated with the litter and sediment. Rather than direct uptake by macrophytes, it is the large reactive surface area provided by the tidal freshwater marsh vegetation that is most crucial for nitrogen transformation, assimilation and short term retention in nutrient rich tidal freshwater marshes. Our results clearly revealed the dominant role of microbes in initial nitrogen retention in marsh ecosystems.

  11. Numerical modeling of the effects of Hurricane Sandy and potential future hurricanes on spatial patterns of salt marsh morphology in Jamaica Bay, New York City

    Science.gov (United States)

    Wang, Hongqing; Chen, Qin; Hu, Kelin; Snedden, Gregg A.; Hartig, Ellen K.; Couvillion, Brady R.; Johnson, Cody L.; Orton, Philip M.

    2017-03-29

    The salt marshes of Jamaica Bay, managed by the New York City Department of Parks & Recreation and the Gateway National Recreation Area of the National Park Service, serve as a recreational outlet for New York City residents, mitigate flooding, and provide habitat for critical wildlife species. Hurricanes and extra-tropical storms have been recognized as one of the critical drivers of coastal wetland morphology due to their effects on hydrodynamics and sediment transport, deposition, and erosion processes. However, the magnitude and mechanisms of hurricane effects on sediment dynamics and associated coastal wetland morphology in the northeastern United States are poorly understood. In this study, the depth-averaged version of the Delft3D modeling suite, integrated with field measurements, was utilized to examine the effects of Hurricane Sandy and future potential hurricanes on salt marsh morphology in Jamaica Bay, New York City. Hurricane Sandy-induced wind, waves, storm surge, water circulation, sediment transport, deposition, and erosion were simulated by using the modeling system in which vegetation effects on flow resistance, surge reduction, wave attenuation, and sedimentation were also incorporated. Observed marsh elevation change and accretion from a rod surface elevation table and feldspar marker horizons and cesium-137- and lead-210-derived long-term accretion rates were used to calibrate and validate the wind-waves-surge-sediment transport-morphology coupled model.The model results (storm surge, waves, and marsh deposition and erosion) agreed well with field measurements. The validated modeling system was then used to detect salt marsh morphological change due to Hurricane Sandy across the entire Jamaica Bay over the short-term (for example, 4 days and 1 year) and long-term (for example, 5 and 10 years). Because Hurricanes Sandy (2012) and Irene (2011) were two large and destructive tropical cyclones which hit the northeast coast, the validated coupled

  12. Geomorphic influences on the contribution of vegetation to soil C accumulation and accretion in Spartina alterniflora marshes

    Directory of Open Access Journals (Sweden)

    T. Elsey-Quirk

    2018-01-01

    Full Text Available Salt marshes are important hotspots of long-term belowground carbon (C storage, where plant biomass and allochthonous C can be preserved in the soil for thousands of years. However, C accumulation rates, as well as the sources of C, may differ depending on environmental conditions influencing plant productivity, allochthonous C deposition, and C preservation. For this study, we examined the relationship between belowground root growth, turnover, decay, above- and belowground biomass, and previously reported longer-term rates of total, labile, and refractory organic C accumulation and accretion in Spartina alterniflora-dominated marshes across two mid-Atlantic, US estuaries. Tidal range, long-term rates of mineral sedimentation, C accumulation, and accretion were higher and salinities were lower in marshes of the coastal plain estuary (Delaware Bay than in the coastal lagoon (Barnegat Bay. We expected that the conditions promoting high rates of C accumulation would also promote high plant productivity and greater biomass. We further tested the influence of environmental conditions on belowground growth (roots + rhizomes, decomposition, and biomass of S. alterniflora. The relationship between plant biomass and C accumulation rate differed between estuaries. In the sediment-limited coastal lagoon, rates of total, labile, and refractory organic C accumulation were directly and positively related to above- and belowground biomass. Here, less flooding and a higher mineral sedimentation rate promoted greater above- and belowground biomass and, in turn, higher soil C accumulation and accretion rates. In the coastal plain estuary, the C accumulation rate was related only to aboveground biomass, which was positively related to the rate of labile C accumulation. Soil profiles indicated that live root and rhizome biomass was positively associated with labile C density for most marshes, yet high labile C densities below the live root zone and in

  13. Impact of soil nematodes on salt-marsh plants : a pilot experiment

    NARCIS (Netherlands)

    Dormann, CF; van der Wal, R

    2001-01-01

    We tested whether the removal of nematodes by means of nematicide application changed plant performance or influenced plant competition. The study involved the two common plant species Artemisia maritima and Festuca rubra growing in intact sods collected from a temperate salt marsh. Half of the sods

  14. 75 FR 65371 - Klamath Marsh National Wildlife Refuge, Klamath County, OR

    Science.gov (United States)

    2010-10-22

    ... impact. SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce the availability of the Final Comprehensive Conservation Plan (CCP) and Finding of No Significant Impact (FONSI) for the Klamath Marsh... rails, Oregon spotted frogs, red-naped sapsuckers, pygmy nuthatches, bald eagles, beaver, and red band...

  15. South Bay Salt Pond Tidal Marsh Restoration at Pond A17 Project

    Science.gov (United States)

    Information about the SFBWQP South Bay Salt Pond Tidal Marsh Restoration at Pond A17 Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  16. Limits on the adaptability of coastal marshes to rising sea level

    Science.gov (United States)

    Kirwan, Matthew L.; Guntenspergen, Glenn R.; D'Alpaos, Andrea; Morris, James T.; Mudd, Simon M.; Temmerman, Stijn

    2010-01-01

    Assumptions of a static landscape inspire predictions that about half of the world's coastal wetlands will submerge during this century in response to sea-level acceleration. In contrast, we use simulations from five numerical models to quantify the conditions under which ecogeomorphic feedbacks allow coastal wetlands to adapt to projected changes in sea level. In contrast to previous sea-level assessments, we find that non-linear feedbacks among inundation, plant growth, organic matter accretion, and sediment deposition, allow marshes to survive conservative projections of sea-level rise where suspended sediment concentrations are greater than ~20 mg/L. Under scenarios of more rapid sea-level rise (e.g., those that include ice sheet melting), marshes will likely submerge near the end of the 21st century. Our results emphasize that in areas of rapid geomorphic change, predicting the response of ecosystems to climate change requires consideration of the ability of biological processes to modify their physical environment.

  17. Short Term Sediment Exchange Between Marshes and Bays Using Beryllium-7 as a Tracer, Fourleague Bay, Louisiana.

    Science.gov (United States)

    Restreppo, G. A.; Bentley, S. J.; Xu, K.; Wang, J.

    2016-12-01

    Modern delta models focus on the availability and exchange of coarse sediment as one of the major factors of deltaic growth or decay. Fine-grained sediment exchange within a river's delta is relatively poorly understood, as is the impact that this exchange has on land building and land loss. To better understand the dynamics of fine grain sediment exchange between river mouth, adjacent bays, and marshland, sediment cores from Fourleague Bay, LA, were collected and analyzed for 7Be, a naturally occurring radioisotope that serves as a marker for recently deposited sediment. Time-series push cores were collected every two months at ten sites, five located across a longitudinal transect in the middle bay and five located along adjacent marshes, from May 2015 to May 2016. All sites fall within 11 to 28 km of the Atchafalaya Delta, along a gradient extending towards the open ocean. Cores were extruded in 2 cm intervals, dried, ground, and analyzed via gamma spectrometry for the presence of 7Be. Inventories of 7Be were then calculated and used to determine bimonthly sedimentation rates over the course twelve months. Sediment deposition on the bay floor and marsh surface were then compared to Atchafalaya River discharge, wind speed and direction, and wave action. Preliminary results indicate patterns of initial fluvial sediment transfer from river to bay floor, then bay floor to marsh surface, with decreasing fluvial influence towards the open ocean. Sediment transport from bay to marsh appears to be coupled with meteorological forcing that induces bay-floor sediment resuspension and the flooding of marsh surfaces. This indirect mechanism of fluvial sediment supply to wetland surfaces may extend the region of influence for sediment delivery from man-made river-sediment diversions.

  18. Exotic Spartina alterniflora invasion alters ecosystem-atmosphere exchange of CH4 and N2O and carbon sequestration in a coastal salt marsh in China.

    Science.gov (United States)

    Yuan, Junji; Ding, Weixin; Liu, Deyan; Kang, Hojeong; Freeman, Chris; Xiang, Jian; Lin, Yongxin

    2015-04-01

    Coastal salt marshes are sensitive to global climate change and may play an important role in mitigating global warming. To evaluate the impacts of Spartina alterniflora invasion on global warming potential (GWP) in Chinese coastal areas, we measured CH4 and N2O fluxes and soil organic carbon sequestration rates along a transect of coastal wetlands in Jiangsu province, China, including open water; bare tidal flat; and invasive S. alterniflora, native Suaeda salsa, and Phragmites australis marshes. Annual CH4 emissions were estimated as 2.81, 4.16, 4.88, 10.79, and 16.98 kg CH4 ha(-1) for open water, bare tidal flat, and P. australis, S. salsa, and S. alterniflora marshes, respectively, indicating that S. alterniflora invasion increased CH4 emissions by 57-505%. In contrast, negative N2O fluxes were found to be significantly and negatively correlated (P carbon sequestration rate of S. alterniflora marsh amounted to 3.16 Mg C ha(-1) yr(-1) in the top 100 cm soil profile, a value that was 2.63- to 8.78-fold higher than in native plant marshes. The estimated GWP was 1.78, -0.60, -4.09, and -1.14 Mg CO2 eq ha(-1) yr(-1) in open water, bare tidal flat, P. australis marsh and S. salsa marsh, respectively, but dropped to -11.30 Mg CO2 eq ha(-1) yr(-1) in S. alterniflora marsh. Our results indicate that although S. alterniflora invasion stimulates CH4 emissions, it can efficiently mitigate increases in atmospheric CO2 and N2O along the coast of China. © 2014 John Wiley & Sons Ltd.

  19. The influence of size, siting, age, and physical characteristics of factory premises on the survival and death of footwear manufacturing establishments in the East Midlands, UK

    OpenAIRE

    P R Mounfield; D J Unwin; K Guy

    1985-01-01

    The propensity of factories in the footwear industry of the East Midlands to survive as active units of production over the period 1957 to 1979 is shown to be associated with at least some of the attributes of size, location, type, and age of the premises occupied. A number of possible causes of establishment or 'case' loss are suggested but the analysis is hampered by the problem of unravelling a complex web of interrelationships between the attributes used. In the second part of the paper a...

  20. Nitrogen cycle of a typical Suaeda salsa marsh ecosystem in the Yellow River estuary.

    Science.gov (United States)

    Mou, Xiaojie; Sun, Zhigao; Wang, Lingling; Wang, Chuanyuan

    2011-01-01

    The nitrogen (N) biological cycle of the Suaeda salsa marsh ecosystem in the Yellow River estuary was studied during 2008 to 2009. Results showed that soil N had significant seasonal fluctuations and vertical distribution. The N/P ratio (15.73 +/- 1.77) of S. salsa was less than 16, indicating that plant growth was limited by both N and P. The N absorption coefficient of S. salsa was very low (0.007), while the N utilization and cycle coefficients were high (0.824 and 0.331, respectively). The N turnover among compartments of S. salsa marsh showed that N uptake from aboveground parts and roots were 2.539 and 0.622 g/m2, respectively. The N translocation from aboveground parts to roots and from roots to soil were 2.042 and 0.076 g/m2, respectively. The N translocation from aboveground living bodies to litter was 0.497 g/m2, the annual N return from litter to soil was far less than 0.368 g/m2, and the net N mineralization in topsoil during the growing season was 0.033 g/m2. N was an important limiting factor in S. salsa marsh, and the ecosystem was classified as unstable and vulnerable. S. salsa was seemingly well adapted to the low-nutrient status and vulnerable habitat, and the nutrient enrichment due to N import from the Yellow River estuary would be a potential threat to the S. salsa marsh. Excessive nutrient loading might favor invasive species and induce severe long-term degradation of the ecosystem if human intervention measures were not taken. The N quantitative relationships determined in our study might provide a scientific basis for the establishment of effective measures.

  1. Ecological effects of climate change on salt marsh wildlife: a case study from a highly urbanized estuary

    Science.gov (United States)

    Thorne, Karen M.; Takekawa, John Y.; Elliott-Fisk, Deborah L.

    2012-01-01

    Coastal areas are high-risk zones subject to the impacts of global climate change, with significant increases in the frequencies of extreme weather and storm events, and sea-level rise forecast by 2100. These physical processes are expected to alter estuaries, resulting in loss of intertidal wetlands and their component wildlife species. In particular, impacts to salt marshes and their wildlife will vary both temporally and spatially and may be irreversible and severe. Synergistic effects caused by combining stressors with anthropogenic land-use patterns could create areas of significant biodiversity loss and extinction, especially in urbanized estuaries that are already heavily degraded. In this paper, we discuss current ideas, challenges, and concerns regarding the maintenance of salt marshes and their resident wildlife in light of future climate conditions. We suggest that many salt marsh habitats are already impaired and are located where upslope transgression is restricted, resulting in reduction and loss of these habitats in the future. In addition, we conclude that increased inundation frequency and water depth will have negative impacts on the demography of small or isolated wildlife meta-populations as well as their community interactions. We illustrate our points with a case study on the Pacific Coast of North America at San Pablo Bay National Wildlife Refuge in California, an area that supports endangered wildlife species reliant on salt marshes for all aspects of their life histories.

  2. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Zellmer, S.D. (Argonne National Lab., IL (United States)); Rastorfer, J.R. (Chicago State Univ., IL (United States). Dept. of Biological Sciences ANL/CSU Cooperative Herbarium, Chicago, IL (United States)); Van Dyke, G.D. (Trinity Christian Coll., Palos Heights, IL (United States). Dept. of Biology)

    1991-07-01

    Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 {times}1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems {ge}2 cm dbh in 10 {times} 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs.

  3. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

    International Nuclear Information System (INIS)

    Zellmer, S.D.; Rastorfer, J.R.; Van Dyke, G.D.

    1991-07-01

    Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 x1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems ≥2 cm dbh in 10 x 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs

  4. Book reviews: Marsh David, The EURO – The Politics of the New Global Currency

    Directory of Open Access Journals (Sweden)

    Isadora Lazar

    2011-03-01

    Full Text Available The EURO – The Politics of the New Global Currency, written by David Marsh and published in both English and German, is a very thorough chronicle of the birth of the European common currency, from its early days, almost half a century before, and of its development until nowadays and even beyond, as it includes considerations on short term dynamics. David Marsh describes the story of the euro in a very complex manner, through a detailed, comprehensive and up to date analysis of the gathered data, making a substantial contribution to understanding the linkages between the political, historical, economic, financial, monetary, strategic and personal determinants of the evolution of the single currency.

  5. Soil salinity data from Grand Liard Bayou and flanking marshes, New Orleans, LA, 2015-12-01 to 2016-03-30 (NCEI Accession 0151634)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The project restored both structural and habitat functions of Grand Liard Bayou and flanking marshes. The project created and nourished marsh and restored a ridge on...

  6. Combining satellite photographs and raster lidar data for channel connectivity in tidal marshes.

    Science.gov (United States)

    Li, Zhi; Hodges, Ben

    2017-04-01

    High resolution airborne lidar is capable of providing topographic detail down to the 1 x 1 m scale or finer over large tidal marshes of a river delta. Such data sets can be challenging to develop and ground-truth due to the inherent complexities of the environment, the relatively small changes in elevation throughout a marsh, and practical difficulties in accessing the variety of flooded, dry, and muddy regions. Standard lidar point-cloud processing techniques (as typically applied in large lidar data collection program) have a tendency to mis-identify narrow channels and water connectivity in a marsh, which makes it difficult to directly use such data for modeling marsh flows. Unfortunately, it is not always practical, or even possible, to access the point cloud and re-analyze the raw lidar data when discrepancies have been found in a raster work product. Faced with this problem in preparing a model of the Trinity River delta (Texas, USA), we developed an approach to integrating analysis of a lidar-based raster with satellite images. Our primary goal was to identify the clear land/water boundaries needed to identify channelization in the available rasterized lidar data. The channel extraction method uses pixelized satellite photographs that are stretched/distorted with image-processing techniques to match identifiable control features in both lidar and photographic data sets. A kmeans clustering algorithm was applied cluster pixels based on their colors, which is effective in separating land and water in a satellite photograph. The clustered image was matched to the lidar data such that the combination shows the channel network. In effect, we are able to use the fact that the satellite photograph is higher resolution than the lidar data, and thus provides connectivity in the clustering at a finer scale. The principal limitation of the method is the where the satellite image and lidar suffer from similar problems For example, vegetation overhanging a narrow

  7. Development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium

    International Nuclear Information System (INIS)

    Teixeira, Catarina; Almeida, C. Marisa R.; Nunes da Silva, Marta; Bordalo, Adriano A.; Mucha, Ana P.

    2014-01-01

    Microbial assisted phytoremediation is a promising, though yet poorly explored, new remediation technique. The aim of this study was to develop autochthonous microbial consortia resistant to cadmium that could enhance phytoremediation of salt-marsh sediments contaminated with this metal. The microbial consortia were selectively enriched from rhizosediments colonized by Juncus maritimus and Phragmites australis. The obtained consortia presented similar microbial abundance but a fairly different community structure, showing that the microbial community was a function of the sediment from which the consortia were enriched. The effect of the bioaugmentation with the developed consortia on cadmium uptake, and the microbial community structure associated to the different sediments were assessed using a microcosm experiment. Our results showed that the addition of the cadmium resistant microbial consortia increased J. maritimus metal phytostabilization capacity. On the other hand, in P. australis, microbial consortia amendment promoted metal phytoextraction. The addition of the consortia did not alter the bacterial structure present in the sediments at the end of the experiments. This study provides new evidences that the development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium might be a simple, efficient, and environmental friendly remediation procedure. Capsule abstract: Development of autochthonous microbial consortia resistant to cadmium that enhanced phytoremediation by salt-marsh plants, without a long term effect on sediment bacterial diversity. - Highlights: • Cd resistant microbial consortia were developed and applied to salt-marsh sediments. • In Phragmites australis the consortia amendment promoted metal phytoextraction. • The consortia addition increased Juncus maritimus phytostabilization capacity. • No long term changes on the rhizosediment bacterial structure were observed

  8. Development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Catarina [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Laboratório de Hidrobiologia e Ecologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); Almeida, C. Marisa R.; Nunes da Silva, Marta [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Bordalo, Adriano A. [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Laboratório de Hidrobiologia e Ecologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); Mucha, Ana P., E-mail: amucha@ciimar.up.pt [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal)

    2014-09-15

    Microbial assisted phytoremediation is a promising, though yet poorly explored, new remediation technique. The aim of this study was to develop autochthonous microbial consortia resistant to cadmium that could enhance phytoremediation of salt-marsh sediments contaminated with this metal. The microbial consortia were selectively enriched from rhizosediments colonized by Juncus maritimus and Phragmites australis. The obtained consortia presented similar microbial abundance but a fairly different community structure, showing that the microbial community was a function of the sediment from which the consortia were enriched. The effect of the bioaugmentation with the developed consortia on cadmium uptake, and the microbial community structure associated to the different sediments were assessed using a microcosm experiment. Our results showed that the addition of the cadmium resistant microbial consortia increased J. maritimus metal phytostabilization capacity. On the other hand, in P. australis, microbial consortia amendment promoted metal phytoextraction. The addition of the consortia did not alter the bacterial structure present in the sediments at the end of the experiments. This study provides new evidences that the development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium might be a simple, efficient, and environmental friendly remediation procedure. Capsule abstract: Development of autochthonous microbial consortia resistant to cadmium that enhanced phytoremediation by salt-marsh plants, without a long term effect on sediment bacterial diversity. - Highlights: • Cd resistant microbial consortia were developed and applied to salt-marsh sediments. • In Phragmites australis the consortia amendment promoted metal phytoextraction. • The consortia addition increased Juncus maritimus phytostabilization capacity. • No long term changes on the rhizosediment bacterial structure were observed.

  9. Atrotorquata lineata as a proxy for Juncus roemerianus, Part I: Atrotorquata lineata as a proxy for Juncus roemerianus in surface sediments from high-level salt marshes in the southeastern United States

    Directory of Open Access Journals (Sweden)

    Marsh Pamela E.

    2016-12-01

    Full Text Available Juncus roemerianus is a plant that occurs at the upper reaches of salt water influence in marshes from Delaware to Texas. In 2006 a palynomorphic fingerprint to identify surface sediment from J. roemerianus marshes was discovered in a South Carolina study (Marsh 2006, Marsh & Cohen 2008. This fingerprint had four components: (1 high palynomorphic abundance, (2 high palynomorphic diversity, (3 high concentration of Fungal Type A (greater than 10% of the palynomorphs in a given sample and (4 the presence of the spores of the fungus Atrotorquata lineata, which occurred in the sediments of J. roemerianus marshes but not in the sediments collected from any other marsh type, even in sediments collected less than a meter away from J. roemerianus.

  10. Salt marsh-mangrove ecotones: using structural gradients to investigate the effects of woody plant encroachment on plant-soil interactions and ecosystem carbon pools

    Science.gov (United States)

    Yando, Erik S.; Osland, Michael J.; Willis, Jonathan M; Day, Richard H.; Krauss, Ken W.; Hester, Mark W.

    2016-01-01

    Changing winter climate extremes are expected to result in the poleward migration of mangrove forests at the expense of salt marshes. Although mangroves and marshes are both highly valued ecosystems, the ecological implications of mangrove expansion have not been fully investigated.

  11. Decomposition of belowground litter and metal dynamics in salt marshes (Tagus Estuary, Portugal)

    International Nuclear Information System (INIS)

    Pereira, Patricia; Cacador, Isabel; Vale, Carlos; Caetano, Miguel; Costa, Ana Luisa

    2007-01-01

    The concentrations of C, Fe, Mn, Zn, Cu, Pb and Cd were determined monthly in decomposing roots of Halimione portulacoides, using litterbag experiments, in two salt marshes of the Tagus estuary with different levels of contamination. Although carbon concentrations varied within a narrow interval during the experiment, litter decomposed rapidly in the first month (weight loss between 0.051 and 0.065 g d -1 ). The time variation of metals was examined in terms of Me/C ratios and metal stocks. Ratios of Fe/C and Mn/C and their metal stocks increased in spring, presumably due to the precipitation of oxides in the surface of decomposing roots. Subsequent decrease of Fe/C and Mn/C ratios suggests the use of Fe and Mn oxides, as electron acceptors, in the organic matter oxidation. Zinc, Cu, Pb and Cd ratios to C were, in general, higher than at initial conditions implying that metal that leached out was slower than carbon. However, metal stocks decreased during the experiment indicating that incorporation or sorption of metals in Fe and Mn oxides did not counterbalance the amount of Zn, Pb and Cd released from decomposing litter. An exception was observed for Cu, since stock in the less contaminated marsh (Pancas) increased during the decomposition, indicating that litter was efficient on Cu binding under more oxidising conditions. These results emphasize the importance of litter decomposition and sediment characteristics on metal cycling in salt marshes

  12. Dendrochronology of Atriplex portulacoides and Artemisia maritima in Wadden Sea salt marshes

    NARCIS (Netherlands)

    Decuyper, M.; Slim, P.A.; Loon-Steensma, van J.M.

    2014-01-01

    The study uses a rather unusual method, dendrochronology, to investigate the growth and survival of Atriplex portulacoides L. and Artemisia maritima L. on salt marshes at two field sites on the Dutch North Sea barrier islands of Terschelling and Ameland. By providing information on longevity of

  13. Progress in inter-departmental audit: the Midlands experience

    International Nuclear Information System (INIS)

    Bonnett, D.E.; Aukett, R.J.; Powley, S.K.

    1995-01-01

    In ensuring the safety of patients in radiotherapy problems can arise from systematic errors in: the basic data, beam calibration, treatment planning or in the regular measurement of machine parameters. One possible method of identifying any such problems is by the use of an audit carried out by another department. In order to devise and test an audit system a co-operative venture between the physics departments at the Walsgrave Hospital, Coventry and the Leicester Royal Infirmary was initiated in 1991 and reported by us at the last biennial meeting. The audit was confined to external beam therapy i.e. electron and photon beams and each audit covered only one machine and one modality. This pilot audit proved to be highly practical, cost effective and of definite benefit. This has now been extended to include the 9 other centres which cover the (English) Midlands: Birmingham, Coventry, Derby, Leicester, Lincoln, Nottingham, Northampton, Stoke-on-Trent and Woverhampton. The group has now been operating for three years, each annual cycle starting in May. In 1993/94 the auditors identified 67 aspects of local Quality Assurance procedures and records which required attention: 29 in basic dosimetry, 23 in machine performance and 15 in machine calibration. In no case was any of these serious. There was considerable variation in the range and frequency of the various checks performed. The errors in the depth doses and field factors measured were in the range -5.5 to +3.5 %. In the planned treatment to a trapezoidal water phantom the errors were in the range -4.0 to +2.0 %. The larger errors occurred only in extreme conditions, which this particular audit is designed to test, and would not have had any significant clinical effect. Nevertheless, a number of possible improvements in depth doses, beam profiles and treatment time calculations were identified. The presentation will include the results of the 1994/95 audit and will discuss any identifiable trends over the three

  14. Will fluctuations in salt marsh-mangrove dominance alter vulnerability of a subtropical wetland to sea-level rise?

    Science.gov (United States)

    McKee, Karen L; Vervaeke, William C

    2018-03-01

    To avoid submergence during sea-level rise, coastal wetlands build soil surfaces vertically through accumulation of inorganic sediment and organic matter. At climatic boundaries where mangroves are expanding and replacing salt marsh, wetland capacity to respond to sea-level rise may change. To compare how well mangroves and salt marshes accommodate sea-level rise, we conducted a manipulative field experiment in a subtropical plant community in the subsiding Mississippi River Delta. Experimental plots were established in spatially equivalent positions along creek banks in monospecific stands of Spartina alterniflora (smooth cordgrass) or Avicennia germinans (black mangrove) and in mixed stands containing both species. To examine the effect of disturbance on elevation dynamics, vegetation in half of the plots was subjected to freezing (mangrove) or wrack burial (salt marsh), which caused shoot mortality. Vertical soil development was monitored for 6 years with the surface elevation table-marker horizon system. Comparison of land movement with relative sea-level rise showed that this plant community was experiencing an elevation deficit (i.e., sea level was rising faster than the wetland was building vertically) and was relying on elevation capital (i.e., relative position in the tidal frame) to survive. Although Avicennia plots had more elevation capital, suggesting longer survival, than Spartina or mixed plots, vegetation type had no effect on rates of accretion, vertical movement in root and sub-root zones, or net elevation change. Thus, these salt marsh and mangrove assemblages were accreting sediment and building vertically at equivalent rates. Small-scale disturbance of the plant canopy also had no effect on elevation trajectories-contrary to work in peat-forming wetlands showing elevation responses to changes in plant productivity. The findings indicate that in this deltaic setting with strong physical influences controlling elevation (sediment accretion

  15. Native-Invasive Plants vs. Halophytes in Mediterranean Salt Marshes: Stress Tolerance Mechanisms in Two Related Species.

    Science.gov (United States)

    Al Hassan, Mohamad; Chaura, Juliana; López-Gresa, María P; Borsai, Orsolya; Daniso, Enrico; Donat-Torres, María P; Mayoral, Olga; Vicente, Oscar; Boscaiu, Monica

    2016-01-01

    Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in "La Albufera" Natural Park, near the city of Valencia (East Spain). The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves-where they are presumably compartmentalized in vacuoles-and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na(+) and Cl(-) contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose) accumulated at higher levels in the former species. This explains the (slightly) higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K(+) transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level-estimated from malondialdehyde accumulation-was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides. Based on these results, we

  16. Native-invasive plants vs. halophytes in Mediterranean salt marshes: Stress tolerance mechanisms in two related species

    Directory of Open Access Journals (Sweden)

    Mohamad eAl Hassan

    2016-04-01

    Full Text Available Dittrichia viscosa is a Mediterranean ruderal species that over the last decades has expanded into new habitats, including coastal salt marshes, ecosystems that are per se fragile and threatened by human activities. To assess the potential risk that this native-invasive species represents for the genuine salt marsh vegetation, we compared its distribution with that of Inula crithmoides, a taxonomically related halophyte, in three salt marshes located in ‘La Albufera’ Natural Park, near the city of Valencia (East Spain. The presence of D. viscosa was restricted to areas of low and moderate salinity, while I. crithmoides was also present in the most saline zones of the salt marshes. Analyses of the responses of the two species to salt and water stress treatments in controlled experiments revealed that both activate the same physiological stress tolerance mechanisms, based essentially on the transport of toxic ions to the leaves – where they are presumably compartmentalized in vacuoles – and the accumulation of specific osmolytes for osmotic adjustment. The two species differ in the efficiency of those mechanisms: salt-induced increases in Na+ and Cl- contents were higher in I. crithmoides than in D. viscosa, and the osmolytes (especially glycine betaine, but also arabinose, fructose and glucose accumulated at higher levels in the former species. This explains the (slightly higher stress tolerance of I. crithmoides, as compared to D. viscosa, established from growth inhibition measurements and their distribution in nature. The possible activation of K+ transport to the leaves under high salinity conditions may also contribute to salt tolerance in I. crithmoides. Oxidative stress level – estimated from malondialdehyde accumulation – was higher in the less tolerant D. viscosa, which consequently activated antioxidant responses as a defense mechanism against stress; these responses were weaker or absent in the more tolerant I. crithmoides

  17. Coordinating across scales: Building a regional marsh bird monitoring program from national and state Initiatives

    Science.gov (United States)

    Shriver, G.W.; Sauer, J.R.

    2008-01-01

    Salt marsh breeding bird populations (rails, bitterns, sparrows, etc.) in eastern North America are high conservation priorities in need of site specific and regional monitoring designed to detect population changes over time. The present status and trends of these species are unknown but anecdotal evidence of declines in many of the species has raised conservation concerns. Most of these species are listed as conservation priorities on comprehensive wildlife plans throughout the eastern U.S. National Wildlife Refuges, National Park Service units, and other wildlife conservation areas provide important salt marsh habitat. To meet management needs for these areas, and to assist regional conservation planning, survey designs are being developed to estimate abundance and population trends for these breeding bird species. The primary purpose of this project is to develop a hierarchical sampling frame for salt marsh birds in Bird Conservation Region (BCR) 30 that will provide the ability to estimate species population abundances on 1) specific sites (i.e. National Parks and National Wildlife Refuges), 2) within states or regions, and 3) within BCR 30. The entire breeding range of Saltmarsh Sharp-tailed and Coastal Plain Swamp sparrows are within BCR 30, providing an opportunity to detect population trends within the entire breeding ranges of two priority species.

  18. An integrated approach to prevent the erosion of salt marshes in the lagoon of Venice

    Directory of Open Access Journals (Sweden)

    Alberto Barausse

    2015-12-01

    Full Text Available The loss of coastal habitats is a widespread problem in Europe. To protect the intertidal salt marshes of the lagoon of Venice from the erosion due to natural and human causes which is diffusely and intensely impacting them, the European Commission has funded the demonstrative project LIFE VIMINE. LIFE VIMINE aims to protect the most interior, hard-to-access salt marshes in the northern lagoon of Venice through an integrated approach, whose core is the prevention of erosion through numerous, small but spatially-diffuse soil-bioengineering protections works, mainly placed through semi-manual labour and with low impact on the environment and the landscape. The effectiveness of protection works in the long term is ensured through routine, temporally-continuous and spatially-diffuse actions of monitoring and maintenance. This method contrasts the common approach to managing hydraulic risk and erosion in Italy which is based on large, one-off and irreversible protection actions. The sustainability of the LIFE VIMINE approach is ensured by the participatory involvement of stakeholders and the recognition that protecting salt marshes means defending the benefits they provide to society through their ecological functions, as well as protecting the jobs linked to the existence or conservation of this habitat.

  19. First results on enzymatic activities in two salt marsh soils under different hydromorphic level and vegetation

    Directory of Open Access Journals (Sweden)

    Carmen Trasar-Cepeda

    2015-12-01

    Full Text Available Salt-marsh soils are soils characterized by non-permanent hydric saturation that, depending on factors like duration of submersion periods, are dominated by different salt-tolerant plant species. The composition of microbial communities is an essential component in trophic dynamics and biogeochemical processes in salt marshes, and determines the level of enzymatic activities, which catalyze the conversion of complex molecules into simpler ones. Despite of this, the enzymatic activities in marsh-soils has not yet been investigated. The aim of this study was to analyze the enzymatic activities in two soil profiles of marsh-soils under different water saturation level and dominated by different plant species [Juncus maritimus Lam and Spartina maritima (Curtis Fernald (Sp]. In both soils, the enzymatic activities were much lower than the levels typically found in terrestrial ecosystems. The enzymatic activities were measured both in air-dried and in re-moistened and incubated soil samples. In air-dried samples, the enzymatic activities were higher in Juncus than in Spartina soil and tended to decrease with depth, being sharper the decrease in Juncus than in Spartina soil. Re-moistened and pre-incubated soils showed a general increase in all the enzymatic activities and throughout the whole soil profile, especially in Spartina soils. Hydrolase activities showed a strong and positive relationship with organic matter content both in air-dried and in re-moistened soil samples, higher in these latter. In general, oxidoreductase activities only showed this relationship in re-moistened soil samples. More studies, preferably using freshly collected soil samples, are needed to understand the relationship between enzymatic activities and these environmental conditions.

  20. Effects of bioremediation agents on oil degradation in mineral and sandy salt marsh sediments

    International Nuclear Information System (INIS)

    Lin, Q.; Mendelssohn, I.A.; Henry, C.B. Jr.; Roberts, P.O.; Walsh, M.M.; Overton, E.B.; Portier, R.J.

    1999-01-01

    Although bioremediation for oil spill cleanup has received considerable attention in recent years, its satisfactory use in the cleanup of oil spills in the wetland environment is still generally untested. A study of the often most used bioremediation agents, fertiliser, microbial product and soil oxidation, as a means of enhancing oil biodegradation in coastal mineral and sandy marsh substrates was conducted in controlled greenhouse conditions. Artificially weathered south Louisiana crude oil was applied to sods of marsh (soil and intact vegetation) at the rate of 2 l m -2 . Fertiliser application enhanced marsh plant growth, soil microbial populations, and oil biodegradation rate. The live aboveground biomass of Spartina alterniflora with fertiliser application was higher than that without fertiliser. The application of fertiliser significantly increased soil microbial respiration rates, indicating the potential for enhancing oil biodegradation. Bioremediation with fertiliser application significantly reduced the total targeted normal hydrocarbons (TTNH) and total targeted aromatic hydrocarbons (TTAH) remaining in the soil, by 81% and 17%, respectively, compared to those of the oil controls. TTNH/hopane and TTAAH/hopane ratios showed a more consistent reduction, further suggesting an enhancement of oil biodegradation by fertilisation. Furthermore, soil type affected oil bioremediation; the extent of fertiliser-enhanced oil biodegradation was greater for sandy (13% TTNH remaining in the treatments with fertiliser compared to the control) than for mineral soils (26% of the control), suggesting that fertiliser application was more effective in enhancing TTNH degradation in the former. Application of microbial product and soil oxidant had no positive effects on the variables mentioned above under the present experimental conditions, suggesting that microbial degraders are not limiting biodegradation in this soil. Thus, the high cost of microbial amendments during

  1. Review of the ecosystem service implications of mangrove encroachment into salt marshes.

    Science.gov (United States)

    Kelleway, Jeffrey J; Cavanaugh, Kyle; Rogers, Kerrylee; Feller, Ilka C; Ens, Emilie; Doughty, Cheryl; Saintilan, Neil

    2017-10-01

    Salt marsh and mangrove have been recognized as being among the most valuable ecosystem types globally in terms of their supply of ecosystem services and support for human livelihoods. These coastal ecosystems are also susceptible to the impacts of climate change and rising sea levels, with evidence of global shifts in the distribution of mangroves, including encroachment into salt marshes. The encroachment of woody mangrove shrubs and trees into herbaceous salt marshes may represent a substantial change in ecosystem structure, although resulting impacts on ecosystem functions and service provisions are largely unknown. In this review, we assess changes in ecosystem services associated with mangrove encroachment. While there is quantitative evidence to suggest that mangrove encroachment may enhance carbon storage and the capacity of a wetland to increase surface elevation in response to sea-level rise, for most services there has been no direct assessment of encroachment impact. On the basis of current understanding of ecosystem structure and function, we theorize that mangrove encroachment may increase nutrient storage and improve storm protection, but cause declines in habitat availability for fauna requiring open vegetation structure (such as migratory birds and foraging bats) as well as the recreational and cultural activities associated with this fauna (e.g., birdwatching and/or hunting). Changes to provisional services such as fisheries productivity and cultural services are likely to be site specific and dependent on the species involved. We discuss the need for explicit experimental testing of the effects of encroachment on ecosystem services in order to address key knowledge gaps, and present an overview of the options available to coastal resource managers during a time of environmental change. © 2017 John Wiley & Sons Ltd.

  2. Tidal Flooding and Vegetation Patterns in a Salt Marsh Tidal Creek Imaged by Low-altitude Balloon Aerial Photography

    Science.gov (United States)

    White, S. M.; Madsen, E.

    2013-12-01

    Inundation of marsh surfaces by tidal creek flooding has implications for the headward erosion of salt marsh creeks, effect of rising sea levels, biological zonation, and marsh ecosystem services. The hydroperiod; as the frequency, duration, depth and flux of water across the marsh surface; is a key factor in salt marsh ecology, but remains poorly understood due to lack of data at spatial scales relevant to tracking the spatial movement of water across the marsh. This study examines how hydroperiod, drainage networks, and tidal creek geomorphology on the vegetation at Crab Haul Creek. Crab Haul Creek is the farthest landward tidal basin in North Inlet, a bar-built estuary in South Carolina. This study measures the hydroperiod in the headwaters Crab Haul Creek with normal and near-IR photos from a helium balloon Helikite at 75-100 m altitude. Photos provide detail necessary to resolve the waterline and delineate the hydroperiod during half tidal cycles by capturing the waterline hourly from the headwaters to a piezometer transect 260 meters north. The Helikite is an ideal instrument for local investigations of surface hydrology due to its maneuverability, low cost, ability to remain aloft for extended time over a fixed point, and ability to capture high-resolution images. Photographs taken from aircraft do not provide the detail necessary to determine the waterline on the marsh surface. The near-IR images make the waterline more distinct by increasing the difference between wet and dry ground. In the headwaters of Crab Haul Creek, individual crab burrows are detected by automated image classification and the number of crab burrows and their spatial density is tracked from January-August. Crab burrows are associated with the unvegetated region at the creek head, and we relate their change over time to the propagation of the creek farther into the tidal basin. Plant zonation is influenced by the hydroperiod, but also may be affected by salinity, water table depth, and

  3. Collaborative decision-analytic framework to maximize resilience of tidal marshes to climate change

    Directory of Open Access Journals (Sweden)

    Karen M. Thorne

    2015-03-01

    Full Text Available Decision makers that are responsible for stewardship of natural resources face many challenges, which are complicated by uncertainty about impacts from climate change, expanding human development, and intensifying land uses. A systematic process for evaluating the social and ecological risks, trade-offs, and cobenefits associated with future changes is critical to maximize resilience and conserve ecosystem services. This is particularly true in coastal areas where human populations and landscape conversion are increasing, and where intensifying storms and sea-level rise pose unprecedented threats to coastal ecosystems. We applied collaborative decision analysis with a diverse team of stakeholders who preserve, manage, or restore tidal marshes across the San Francisco Bay estuary, California, USA, as a case study. Specifically, we followed a structured decision-making approach, and we using expert judgment developed alternative management strategies to increase the capacity and adaptability to manage tidal marsh resilience while considering uncertainties through 2050. Because sea-level rise projections are relatively confident to 2050, we focused on uncertainties regarding intensity and frequency of storms and funding. Elicitation methods allowed us to make predictions in the absence of fully compatible models and to assess short- and long-term trade-offs. Specifically we addressed two questions. (1 Can collaborative decision analysis lead to consensus among a diverse set of decision makers responsible for environmental stewardship and faced with uncertainties about climate change, funding, and stakeholder values? (2 What is an optimal strategy for the conservation of tidal marshes, and what strategy is robust to the aforementioned uncertainties? We found that when taking this approach, consensus was reached among the stakeholders about the best management strategies to maintain tidal marsh integrity. A Bayesian decision network revealed that a

  4. Collaborative decision-analytic framework to maximize resilience of tidal marshes to climate change

    Science.gov (United States)

    Thorne, Karen M.; Mattsson, Brady J.; Takekawa, John Y.; Cummings, Jonathan; Crouse, Debby; Block, Giselle; Bloom, Valary; Gerhart, Matt; Goldbeck, Steve; Huning, Beth; Sloop, Christina; Stewart, Mendel; Taylor, Karen; Valoppi, Laura

    2015-01-01

    Decision makers that are responsible for stewardship of natural resources face many challenges, which are complicated by uncertainty about impacts from climate change, expanding human development, and intensifying land uses. A systematic process for evaluating the social and ecological risks, trade-offs, and cobenefits associated with future changes is critical to maximize resilience and conserve ecosystem services. This is particularly true in coastal areas where human populations and landscape conversion are increasing, and where intensifying storms and sea-level rise pose unprecedented threats to coastal ecosystems. We applied collaborative decision analysis with a diverse team of stakeholders who preserve, manage, or restore tidal marshes across the San Francisco Bay estuary, California, USA, as a case study. Specifically, we followed a structured decision-making approach, and we using expert judgment developed alternative management strategies to increase the capacity and adaptability to manage tidal marsh resilience while considering uncertainties through 2050. Because sea-level rise projections are relatively confident to 2050, we focused on uncertainties regarding intensity and frequency of storms and funding. Elicitation methods allowed us to make predictions in the absence of fully compatible models and to assess short- and long-term trade-offs. Specifically we addressed two questions. (1) Can collaborative decision analysis lead to consensus among a diverse set of decision makers responsible for environmental stewardship and faced with uncertainties about climate change, funding, and stakeholder values? (2) What is an optimal strategy for the conservation of tidal marshes, and what strategy is robust to the aforementioned uncertainties? We found that when taking this approach, consensus was reached among the stakeholders about the best management strategies to maintain tidal marsh integrity. A Bayesian decision network revealed that a strategy

  5. In search of the genetic footprints of Sumerians: a survey of Y-chromosome and mtDNA variation in the Marsh Arabs of Iraq

    Directory of Open Access Journals (Sweden)

    Olivieri Anna

    2011-10-01

    Full Text Available Abstract Background For millennia, the southern part of the Mesopotamia has been a wetland region generated by the Tigris and Euphrates rivers before flowing into the Gulf. This area has been occupied by human communities since ancient times and the present-day inhabitants, the Marsh Arabs, are considered the population with the strongest link to ancient Sumerians. Popular tradition, however, considers the Marsh Arabs as a foreign group, of unknown origin, which arrived in the marshlands when the rearing of water buffalo was introduced to the region. Results To shed some light on the paternal and maternal origin of this population, Y chromosome and mitochondrial DNA (mtDNA variation was surveyed in 143 Marsh Arabs and in a large sample of Iraqi controls. Analyses of the haplogroups and sub-haplogroups observed in the Marsh Arabs revealed a prevalent autochthonous Middle Eastern component for both male and female gene pools, with weak South-West Asian and African contributions, more evident in mtDNA. A higher male than female homogeneity is characteristic of the Marsh Arab gene pool, likely due to a strong male genetic drift determined by socio-cultural factors (patrilocality, polygamy, unequal male and female migration rates. Conclusions Evidence of genetic stratification ascribable to the Sumerian development was provided by the Y-chromosome data where the J1-Page08 branch reveals a local expansion, almost contemporary with the Sumerian City State period that characterized Southern Mesopotamia. On the other hand, a more ancient background shared with Northern Mesopotamia is revealed by the less represented Y-chromosome lineage J1-M267*. Overall our results indicate that the introduction of water buffalo breeding and rice farming, most likely from the Indian sub-continent, only marginally affected the gene pool of autochthonous people of the region. Furthermore, a prevalent Middle Eastern ancestry of the modern population of the marshes of

  6. Study of erosion processes in the Tinto salt-marshes with remote sensing images.

    Science.gov (United States)

    2016-01-01

    Both climatic factors and the sea wave energy are two important factors to study the tidal wetlands. One of the most important wetlands in the Southwest of the Iberian Peninsula is the Tinto salt-marshes, the third largest wetland in Andalusia after ...

  7. Organochlorine pesticides and thiamine in eggs of largemouth bass and American alligators and their relationship with early life-stage mortality

    Science.gov (United States)

    Sepulveda, M.S.; Wiebe, J.J.; Honeyfield, D.C.; Rauschenberger, H.R.; Hinterkopf, J.P.; Johnson, W.E.; Gross, T.S.

    2004-01-01

    Thiamine deficiency has been linked to early mortality syndrome in salmonids in the Great Lakes. This study was conducted to compare thiamine concentrations in American alligators (Alligator mississippiensis) and Florida largemouth bass (Micropterus salmoides floridanus) eggs from sites with high embryo mortality and high exposure to organochlorine pesticides (OCPs) (Lakes Apopka and Griffin, and Emeralda Marsh, Florida, USA) to those from sites that have historically exhibited low embryo mortality and low OCPs (Lakes Woodruff and Orange, Florida). During June-July 2000, 20 alligator clutches were collected from these sites, artificially incubated, and monitored for embryo mortality. Thiamine and OCPs were measured in one egg/clutch. During February 2002, 10 adult female bass were collected from Emeralda Marsh and Lake Woodruff and mature ovaries analyzed for thiamine and OCP concentrations. Although ovaries from the Emeralda Marsh bass contained almost 1,000-fold more OCPs compared with the reference site, Lake Woodruff, there were no differences in thiamine concentrations between sites (11,710 vs. 11,857 pmol/g). In contrast, alligator eggs from the reference site had five times the amount of thiamine compared with the contaminated sites (3,123 vs. 617 pmol/g). Similarly, clutches with > 55% hatch rates had significantly higher concentrations of thiamine compared with clutches with eggs. ?? Wildlife Disease Association 2004.

  8. Variations in organic carbon chemistry in the Gulf Coast and coastal marshes following the Deepwater Horizon oil spill

    Science.gov (United States)

    Holloway, J. M.; Orem, W. H.; Aiken, G.; Varonka, M. S.; Butler, K.; Kokaly, R. F.

    2011-12-01

    Record volumes of oil released from the Macondo well following the explosion of the Deepwater Horizon offshore oil-drilling platform in the Gulf of Mexico significantly impacted coastal marshes in Barataria Bay, Louisiana. Remote sensing and water sampling was conducted by the U.S. Geological Survey to evaluate the extent of impact. Water samples were collected offshore from near the spill site July 5-10, 2010 to characterize molecular organic carbon chemistry on unfiltered samples and dissolved organic carbon (DOC) on filtered samples. Three field visits were conducted in July 7-10, August 12-14, and August 24-26, 2010, to collect samples from the soil-water interface in coastal marshes along lower Barataria Bay and the Bird's Foot Delta at the distal end of the Mississippi River Delta. Visible oil in the marsh was observed as thick coatings on vegetation and soil and as sheens at the water surface. Samples were extracted for hydrocarbons with dichloromethane, separated into aliphatic, aromatic and polar compound classes using standard column techniques, and analyzed by gas chromatography/mass spectrometry. A significant amount of oil was observed "dissolved" in the water column with a hydrocarbon distribution resembling that of the surface oil slick. While oils maintained many of the more volatile lower molecular weight components near the spill site, these were mostly gone in the onshore Barataria Bay samples, leaving mostly higher molecular weight components. Dissolved organic carbon was characterized using concentration, fluorescence index (FI), specific ultratviolet absorbance (SUVA) and excitation/emission fluorescence (EEM). Offshore samples had distinctive EEMs patterns, SUVA and FI. With few exceptions, marsh samples had EEMs patterns more similar to previously extracted organic matter from the Mississippi River than to the offshore oil. In spite of visible oil sheen in unfiltered water from contaminated shorelines and no visible sign of impact on

  9. Loop migration in adult marsh harriers Circus aeruginosus, as revealed by satellite telemetry

    DEFF Research Database (Denmark)

    H. G. Klaassen, Raymond; Strandberg, Roine; Hake, Mikael

    2010-01-01

    level, for example by analysing ring recoveries. Here we study loop migration of individual marsh harriersCircus aeruginosus tracked by satellite telemetry. We show that despite a generally narrow migration corridor the harriers travelled in a distinct clockwise loop through Africa and southern Europe...

  10. MICROBIAL COLONIZATION, RESPIRATION, AND BREAKDOWN OF MAPLE LEAVES ALONG A STREAM-MARSH CONTINUUM

    Science.gov (United States)

    Breakdown rates, macroinvertebrate and bacterial colonization, and microbial respiration were measured on decaying maple (Acer saccharum) leaves at three sites along a stream-marsh continuum. Breakdown rates (-k+-SE) were 0.0284+-0.0045 d-1 for leaves in a high-gradient, non-tida...

  11. Restoration of pyritic colliery waste with sewage sludge in the Midlands coalfield, England, United Kingdom

    International Nuclear Information System (INIS)

    Humphries, R.N.; McQuire, G.E.; Sly, M.

    1994-01-01

    A trial was set up in 1990 in the Midlands coalfield in the United Kingdom (UK) to evaluate the use of sewage sludge to revegetate colliery waste tips containing 1--2% sulfur as iron pyrites. The rate of sewage sludge application is currently restricted by legislation and codes of practice to maximum concentrations of potentially toxic elements (copper, nickel, zinc, etc.) in the soil or waste after application. Following this guidance, an application rate of 250 mt/ha dry solids was applied at the trial site. At this rate, the colliery waste became extremely acidic pH <4.0. From experience elsewhere, much higher levels have been found to be necessary to control acidification in the absence of other measures or treatments. In view of the restriction on the amount of sewage sludge that can be applied, it is recommended that the current practice of covering fresh colliery wastes with soil or low sulfur spoil to a minimum depth of 0.45m is continued in the UK. Where this is not possible, the sludge must always be applied with sufficient neutralizing agent to control the potential acidity. If the acidity cannot be maintained above pH 5.0, the guidelines do not permit the application of sewage sludge

  12. Delayed recolonization of foraminifera in a suddenly flooded tidal (former freshwater) marsh in Oregon (USA): Implications for relative sea-level reconstructions

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin P.; Khan, Nicole S.; Nelson, Alan R.; Witter, Robert C.; Engelhart, Simon E.; Ewald, Michael; Brophy, Laura; Bridgeland, William T.

    2016-04-01

    Stratigraphic sequences beneath salt marshes along the U.S. Pacific Northwest coast preserve 7000 years of plate-boundary earthquakes at the Cascadia subduction zone. The sequences record rapid rises in relative sea level during regional coseismic subsidence caused by great earthquakes and gradual falls in relative sea level during interseismic uplift between earthquakes. These relative sea-level changes are commonly quantified using foraminiferal transfer functions with the assumption that foraminifera rapidly recolonize salt marshes and adjacent tidal flats following coseismic subsidence. The restoration of tidal inundation in the Ni-les'tun unit (NM unit) of the Bandon Marsh National Wildlife Refuge (Oregon), following extensive dike removal in August 2011, allowed us to directly observe changes in foraminiferal assemblages that occur during rapid "coseismic" (simulated by dike removal with sudden tidal flooding) and "interseismic" (stabilization of the marsh following flooding) relative sea-level changes analogous to those of past earthquake cycles. We analyzed surface sediment samples from 10 tidal stations at the restoration site (NM unit) from mudflat to high marsh, and 10 unflooded stations in the Bandon Marsh control site. Samples were collected shortly before and at 1- to 6-month intervals for 3 years after tidal restoration of the NM unit. Although tide gauge and grain-size data show rapid restoration of tides during approximately the first 3 months after dike removal, recolonization of the NM unit by foraminifera was delayed at least 10 months. Re-establishment of typical tidal foraminiferal assemblages, as observed at the control site, required 31 months after tidal restoration, with Miliammina fusca being the dominant pioneering species. If typical of past recolonizations, this delayed foraminiferal recolonization affects the accuracy of coseismic subsidence estimates during past earthquakes because significant postseismic uplift may shortly follow

  13. Effects of Deepwater Horizon Oil on the Movement and Survival of Marsh Periwinkle Snails (Littoraria irrorata).

    Science.gov (United States)

    Garner, T Ross; Hart, Michael A; Sweet, Lauren E; Bagheri, Hanna T J; Morris, Jeff; Stoeckel, James A; Roberts, Aaron P

    2017-08-01

    The Deepwater Horizon (DWH) oil spill resulted in the release of millions of barrels of oil into the Gulf of Mexico, and some marsh shorelines experienced heavy oiling including vegetation laid over under the weight of oil. Periwinkle snails (Littoraria irrorata) are a critical component of these impacted habitats, and population declines following oil spills, including DWH, have been documented. This study determined the effects of oil on marsh periwinkle movement and survivorship following exposure to oil. Snails were placed in chambers containing either unoiled or oiled laid over vegetation to represent a heavily impacted marsh habitat, with unoiled vertical structure at one end. In the first movement assay, snail movement to standing unoiled vegetation was significantly lower in oiled chambers (oil thickness ≈ 1 cm) compared to unoiled chambers, as the majority (∼75%) of snails in oiled habitats never reached standing unoiled vegetation after 72 h. In a second movement assay, there was no snail movement standing unoiled structure in chambers with oil thicknesses of 0.1 and 0.5 cm, while 73% of snails moved in unoiled chambers after 4h. A toxicity assay was then conducted by exposing snails to oil coated Spartina stems in chambers for periods up to 72 h, and mortality was monitored for 7 days post exposure. Snail survival decreased with increasing exposure time, and significant mortality (∼35%) was observed following an oil exposure of less than 24 h. Here, we have shown that oil impeded snail movement to clean habitat over a short distance and resulted in oil-exposure times that decreased survival. Taken together, along with declines documented by others in field surveys, these results suggest that marsh periwinkle snails may have been adversely affected following exposure to DWH oil.

  14. Elemental analysis of some ethnomedicinaly important hydrophytes and marsh plants of India used in traditional medicine

    Institute of Scientific and Technical Information of China (English)

    Somnath Bhowmik; Badal Kumar Datta

    2012-01-01

    Objective: To study the elemental content of some ethnomedicinaly important hydrophytes and marsh plant of Tripura, India. Methods: With the help of standardize d questionnaires, 10 informants were interviewed on the medicinal use of hydrophytes and marsh plants of Tripura, India during 2009-2010.The elemental content of those plants were determined using Atomic Absorption Spectrophotometer. Results: A total of 8 plant species belonging to 8 different genera and 8 family were reported with their ethnomedicinaly uses. Among the different plant part used leaves and young tender shoots are most frequently used for the treatment of different disease. The hydrophytes and marsh plants are mostly used for the treatment of dysentery and other hepatic disorder. Different elemental constituents at trace levels of plants play an effective role in the medicines prepared. Elemental composition of eight ethno-medicinally important hydrophytes and marsh plants of Tripura, India have been determined using Atomic Absorption Spectrophotometer (AAS). A total of 11 elements K+, Mg+2, Ca+2, Na+ , Fe+2, Mn+2, Cu+3, Mn+2, Cu+3, Cr+3, Zn+2, Pb+4 and Cd+2 have been measured. Their concentrations were found to vary in different samples. Toxic elements Cd and Pb were also found but at very low concentration. Medicinal properties of these plant samples and their elemental distribution have been correlated. These results can be used to set new standards for prescribing the dosage of the herbal drugs prepared from these plant materials in herbal remedies and in pharmaceutical companies. Conclusions: The data obtained in the present work will be useful in synthesis of new herbal drugs with various combinations of plants, which can be used in the treatment of different diseases at global level.

  15. Mercury adsorption in the Mississippi River deltaic plain freshwater marsh soil of Louisiana Gulf coastal wetlands.

    Science.gov (United States)

    Park, Jong-Hwan; Wang, Jim J; Xiao, Ran; Pensky, Scott M; Kongchum, Manoch; DeLaune, Ronald D; Seo, Dong-Cheol

    2018-03-01

    Mercury adsorption characteristics of Mississippi River deltaic plain (MRDP) freshwater marsh soil in the Louisiana Gulf coast were evaluated under various conditions. Mercury adsorption was well described by pseudo-second order and Langmuir isotherm models with maximum adsorption capacity of 39.8 mg g -1 . Additional fitting of intraparticle model showed that mercury in the MRDP freshwater marsh soil was controlled by both external surface adsorption and intraparticle diffusion. The partition of adsorbed mercury (mg g -1 ) revealed that mercury was primarily adsorbed into organic-bond fraction (12.09) and soluble/exchangeable fraction (10.85), which accounted for 63.5% of the total adsorption, followed by manganese oxide-bound (7.50), easily mobilizable carbonate-bound (4.53), amorphous iron oxide-bound (0.55), crystalline Fe oxide-bound (0.41), and residual fraction (0.16). Mercury adsorption capacity was generally elevated along with increasing solution pH even though dominant species of mercury were non-ionic HgCl 2 , HgClOH and Hg(OH) 2  at between pH 3 and 9. In addition, increasing background NaCl concentration and the presence of humic acid decreased mercury adsorption, whereas the presence of phosphate, sulfate and nitrate enhanced mercury adsorption. Mercury adsorption in the MRDP freshwater marsh soil was reduced by the presence of Pb, Cu, Cd and Zn with Pb showing the greatest competitive adsorption. Overall the adsorption capacity of mercury in the MRDP freshwater marsh soil was found to be significantly influenced by potential environmental changes, and such factors should be considered in order to manage the risks associated with mercury in this MRDP wetland for responding to future climate change scenarios. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Elevated CO2 stimulates marsh elevation gain, counterbalancing sea-level rise.

    Science.gov (United States)

    Langley, J Adam; McKee, Karen L; Cahoon, Donald R; Cherry, Julia A; Megonigal, J Patrick

    2009-04-14

    Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase rates of soil elevation gain to avoid permanent conversion to open water. The maximal rate of SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation of organic matter is equally important for many wetlands. Plant productivity drives organic matter dynamics and is sensitive to global change factors, such as rising atmospheric CO(2) concentration. It remains unknown how global change will influence organic mechanisms that determine future tidal wetland viability. Here, we present experimental evidence that plant response to elevated atmospheric [CO(2)] stimulates biogenic mechanisms of elevation gain in a brackish marsh. Elevated CO(2) (ambient + 340 ppm) accelerated soil elevation gain by 3.9 mm yr(-1) in this 2-year field study, an effect mediated by stimulation of below-ground plant productivity. Further, a companion greenhouse experiment revealed that the CO(2) effect was enhanced under salinity and flooding conditions likely to accompany future SLR. Our results indicate that by stimulating biogenic contributions to marsh elevation, increases in the greenhouse gas, CO(2), may paradoxically aid some coastal wetlands in counterbalancing rising seas.

  17. Elevated CO2 stimulates marsh elevation gain, counterbalancing sea-level rise

    Science.gov (United States)

    Langley, J. Adam; McKee, Karen L.; Cahoon, Donald R.; Cherry, Julia A.; Megonigal, J. Patrick

    2009-01-01

    Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase rates of soil elevation gain to avoid permanent conversion to open water. The maximal rate of SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation of organic matter is equally important for many wetlands. Plant productivity drives organic matter dynamics and is sensitive to global change factors, such as rising atmospheric CO2 concentration. It remains unknown how global change will influence organic mechanisms that determine future tidal wetland viability. Here, we present experimental evidence that plant response to elevated atmospheric [CO2] stimulates biogenic mechanisms of elevation gain in a brackish marsh. Elevated CO2 (ambient + 340 ppm) accelerated soil elevation gain by 3.9 mm yr−1 in this 2-year field study, an effect mediated by stimulation of below-ground plant productivity. Further, a companion greenhouse experiment revealed that the CO2 effect was enhanced under salinity and flooding conditions likely to accompany future SLR. Our results indicate that by stimulating biogenic contributions to marsh elevation, increases in the greenhouse gas, CO2, may paradoxically aid some coastal wetlands in counterbalancing rising seas. PMID:19325121

  18. Methane Production and Transport within the Marsh Biome of Biosphere 2

    Science.gov (United States)

    Molnar, Jennifer; Goodridge, Kelven

    1997-01-01

    In recent decades, the concentration of methane in the earth's atmosphere increased 1-2% annually. It's rate of increases, combined with methane's effectiveness as a greenhouse gas, has led to an intensive research effort to determine the sources and sinks of the gas in the environment. Biosphere 2 offers a unique opportunity to contribute to the effort because it lacks a major photochemical sink present in the Earth's atmosphere. Researchers can therefore concentrate on biological processes involved in methane cycles. Wetlands are a large source of atmospheric methane, due to anoxic conditions in the sediments and the abundance of organic materials. In order to determine if these conditions in Biosphere 2 also promote methane production, this study looked for the fluxes of methane and methods of transport of the gas from from the water and sediments to the atmosphere in the Marsh Biome. Fluxes of methane from the sediments and waters were measured using static chambers, peepers, and leaf bags. Fluxes and vertical profiles of methane in the sediments show that substantial amounts of methane are being produced in the marsh and are being transported into the Biosphere 2 environment.

  19. Impact of vegetation die-off on spatial flow patterns over a tidal marsh

    NARCIS (Netherlands)

    Temmerman, S.; Moonen, P.; Schoelynck, J.; Govers, G.; Bouma, T.J.

    2012-01-01

    Large-scale die-off of tidal marsh vegetation, caused by global change, is expected to change flow patterns over tidal wetlands, and hence to affect valuable wetland functions such as reduction of shoreline erosion, attenuation of storm surges, and sedimentation in response to sea level rise. This

  20. Optimal screening mammography reading volumes; evidence from real life in the East Midlands region of the NHS Breast Screening Programme

    International Nuclear Information System (INIS)

    Cornford, E.; Reed, J.; Murphy, A.; Bennett, R.; Evans, A.

    2011-01-01

    Aim: To assess real-life reader performance as a function of both volume of mammograms read and reading experience in a multicentre cohort. Materials and methods: Thirty-seven film readers from the East Midlands Breast Screening Programme had 3 years of consecutive screen reading results available for comparison. Markers of screening performance as the first film reader [cancer detection rates, small cancer detection rates, recall rates, positive predictive value of recall (PPV), and missed cancers] were compared with both volume of films read and years of film reading experience. For reading volume, readers were categorized according to film reading volume over the 3 year period: <15,000 (i.e., on average less than the recommended 5000/year); 15-<20,000; 20-<25,000; and ≥25,000. For years of experience, readers were categorized into the following groups: <5 years, 5-<10 years, 10-<15 years, and 15-<20 years. Results: There was no evidence to suggest a relationship between years of film reading experience and film-reading performance. For reading volume, there was a significant difference in the distribution of cancer-detection rate between the four groups (p = 0.01); however, there was no difference in small cancer-detection rates, missed cancers or PPV. The median cancer detection rate in the high-volume group (≥25,000 mammograms/3 years) was significantly lower than the other groups combined (6.9 per 1000 women screened versus 7.9 per 1000 women screened). The lowest median recall rate was also in the high-volume group, whilst those readers not meeting the NHSBSP minimum requirement had the highest median recall rate; however, there was borderline evidence to suggest a difference in the distribution of recall rates between the four groups. Conclusion: The data from the East Midlands do not provide any evidence for reducing the threshold volume of 5000 cases /year. However, there appears to be an upper limit above which reader performance deteriorates in

  1. The shift from hold-the-line to management retreat and implications to coastal change: Farlington Marshes, a case of conflicts

    Science.gov (United States)

    Esteves, L. S.; Foord, J.; Draux, H.

    2012-04-01

    Although it can be argued that coastal erosion is primarily a natural process, in many developed coasts it has been triggered or intensified by human-induced activities affecting local sediment budget and pathways. For a long time, coastal engineering works have been used to reshape the world's coastlines to accommodate for social and economic needs. The realisation that such interference with natural processes would result in cascading environmental impacts at various temporal and spatial scales is relatively recent. As a result, a series of regulations have been implemented to mitigate further damage to coastal environments and compensatory measures are now required as part of licensing approval for certain coastal activities. For example, the construction and upgrade of coastal defences are now constrained due to potential detrimental impacts caused on adjacent designated European habitats or species. This study evaluates how a shift from socio-economic needs to a natural-conservancy focus is influencing coastal management approaches in England and the implications for coastal evolution. More specifically, Farlington Marshes (Portsmouth, southern England) will be used as a case study to assess how complex interactions between natural coastal processes, coastal defences and the need for environmental conservation are affecting shoreline changes, evolution of intertidal habitats and biodiversity. Farlington Marshes are designated grazing marshes of national and European importance and a valued recreational area used by local residents. Seawalls built in the 18th century protect the freshwater habitats from flooding but cause detrimental impact on intertidal habitats of Langstone Habour, which are also designated conservation areas (Ramsar, Special Areas of Conservation, Special Protection Areas, Sites of Special Scientific Interest). The presence of seawalls has caused erosion and coastal squeeze, which are the main causes of the rapid loss of saltmarshes observed

  2. Development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium.

    Science.gov (United States)

    Teixeira, Catarina; Almeida, C Marisa R; Nunes da Silva, Marta; Bordalo, Adriano A; Mucha, Ana P

    2014-09-15

    Microbial assisted phytoremediation is a promising, though yet poorly explored, new remediation technique. The aim of this study was to develop autochthonous microbial consortia resistant to cadmium that could enhance phytoremediation of salt-marsh sediments contaminated with this metal. The microbial consortia were selectively enriched from rhizosediments colonized by Juncus maritimus and Phragmites australis. The obtained consortia presented similar microbial abundance but a fairly different community structure, showing that the microbial community was a function of the sediment from which the consortia were enriched. The effect of the bioaugmentation with the developed consortia on cadmium uptake, and the microbial community structure associated to the different sediments were assessed using a microcosm experiment. Our results showed that the addition of the cadmium resistant microbial consortia increased J. maritimus metal phytostabilization capacity. On the other hand, in P. australis, microbial consortia amendment promoted metal phytoextraction. The addition of the consortia did not alter the bacterial structure present in the sediments at the end of the experiments. This study provides new evidences that the development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium might be a simple, efficient, and environmental friendly remediation procedure. Development of autochthonous microbial consortia resistant to cadmium that enhanced phytoremediation by salt-marsh plants, without a long term effect on sediment bacterial diversity. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. The discharge of nitrate-contaminated groundwater from developed shoreline to marsh-fringed estuary

    Science.gov (United States)

    Portnoy, J.W.; Nowicki, B.L.; Roman, C.T.; Urish, D.W.

    1998-01-01

    As residential development, on-site wastewater disposal, and groundwater contamination increase in the coastal zone, assessment of nutrient removal by soil and sedimentary processes becomes increasingly important. Nitrogen removal efficiency depends largely on the specific flow paths taken by groundwater as it discharges into nitrogen-limited estuarine waters. Shoreline salinity surveys, hydraulic studies, and thermal infrared imagery indicated that groundwater discharge into the Nauset Marsh estuary (Eastham, Massachusetts) occurred in high-velocity seeps immediately seaward of the upland-fringing salt marsh. Discharge was highly variable spatially and occurred through permeable, sandy sediments during low tide. Seepage chamber monitoring showed that dissolved inorganic nitrogen (principally nitrate) traversed nearly conservatively from the aquifer through shallow estuarine sediments to coastal waters at flux rates of 1–3 mmol m−2 h−1. A significant relationship between pore water NO3-N concentrations and NO3-N flux rates may provide a rapid method of estimating nitrogen loading from groundwater to the water column.

  4. The impact of herbivores on nitrogen mineralization rate: consequences for salt-marsh succession.

    Science.gov (United States)

    van Wijnen, Harm J; van der Wal, René; Bakker, Jan P

    1999-02-01

    Soil net N-mineralization rate was measured along a successional gradient in salt-marsh sites that were grazed by vertebrate herbivores, and in 5-year-old exclosures from which the animals were excluded. Mineralization rate was significantly higher at ungrazed than at grazed sites. In the absence of grazing, mineralization rate increased over the course of succession, whereas it remained relatively low when sites were grazed. The largest differences in mineralization rate between grazed and ungrazed sites were found at late successional stages where grazing pressure was lowest. The amount of plant litter was significantly lower at grazed sites. In addition, the amount of litter and potential litter (non-woody, live shoots) was linearly related to net N-mineralization rate. This implies that herbivores reduced mineralization rate by preventing litter accumulation. Bulk density was higher at grazed salt-marsh sites than at ungrazed sites. This factor may also have contributed to the differences in net N-mineralization rate between grazed and ungrazed sites.

  5. Effects of soil abiotic factors on the plant morphology in an intertidal salt marsh, Yellow River Delta, China

    Science.gov (United States)

    Li, Shanze; Cui, Baoshan; Bai, Junhong; Xie, Tian; Yan, Jiaguo; Wang, Qing; Zhang, Shuyan

    2018-02-01

    Plant morphology plays important role in studying biogeography in many ecosystems. Suadea salsa, as a native plant community of northern China and an important habitat for diversity of waterbirds and macrobenthos, has often been overlooked. Nowadays, S. salsa community is facing great loss due to coastal reclamation activities and natural disturbances. To maintain and restore S. salsa community, it's important to address the plant morphology across marsh zones, as well as its relationships with local soil abiotic conditions. In our studied intertidal salt marsh, we found that less flood disturbance frequency, softer soil conditions, rich soil organic matter, total carbon and total nitrogen, lower water depth and water content, less species competition will benefit S. salsa plant in the morphology of high coverage, above-ground biomass, shoot height and leaf length. Lower soil porewater salinity will benefit the below-ground biomass of S. salsa. Thus, we recommend managers help alleviate soil abiotic stresses in the intertidal salt marshes, making the soil conditions more suitable for S. salsa growth and succession.

  6. NATIVE AND INTRODUCED LARVAL FISHES IN SUISAN MARSH, CALIFORNIA,: THE EFFECTS OF FRESHWATER FLOW

    Science.gov (United States)

    We sampled ichthyoplankton weekly in Suisun Marsh in the San Francisco Estuary from February to June each year from 1994 to 1999. We collected approximately 227,900 fish, predominantly shimofuri goby Tridentiger bifasciatus (60%) and prickly sculpin Cottus asper (33%). Principal ...

  7. SEASONAL-VARIATION IN THE SEX-RATIO OF MARSH HARRIER CIRCUS-AERUGINOSUS BROODS

    NARCIS (Netherlands)

    ZIJLSTRA, M; DAAN, S; BRUINENBERGRINSMA, J

    1992-01-01

    1. Analysis of the sexes of 2260 nestlings in 735 marsh harrier broods revealed an overall excess [sex ratio (SR) = 54.8%] of males, and a significant increase in the proportion of males with progressive laying date (d = day of the year): In [SR/(1-SR)] = -1.286 + 0.013 d. 2. We argue that it is

  8. Carbon dioxide exchange rates from short- and long-hydroperiod Everglades freshwater marsh

    Science.gov (United States)

    K. L. Jimenez; G. Starr; C. L. Staudhammer; J. L. Schedlbauer; H. W. Loescher; Sparkle L Malone; S. F. Oberbauer

    2012-01-01

    Everglades freshwater marshes were once carbon sinks, but human-driven hydrologic changes have led to uncertainty about the current state of their carbon dynamics. To investigate the effect of hydrology on CO2 exchange, we used eddy covariance measurements for 2 years (2008-2009) in marl (short-hydroperiod) and peat (long-hydroperiod) wetlands in Everglades National...

  9. The impact of herbivores on nitrogen mineralization rate : consequences for salt-marsh succession

    NARCIS (Netherlands)

    van Wijnen, HJ; van der Wal, R; Bakker, JP

    Soil net N-mineralization rate was measured along a successional gradient in salt-marsh sites that were grazed by vertebrate herbivores, and in 5-year-old exclosures from which the animals were excluded. Mineralization rate was significantly higher at ungrazed than at grazed sites. In the absence of

  10. Brackish marsh zones as a waterfowl habitat resource in submerged aquatic vegetation beds in the northern Gulf of Mexico

    Science.gov (United States)

    DeMarco, Kristin; Hillmann, Eva R.; Brasher, Michael G.; LaPeyre, Megan K.

    2016-01-01

    Submerged aquatic vegetation (SAV) beds are shallow coastal habitats that are increasingly exposed to the effects of sea-level rise (SLR). In the northern Gulf of Mexico (nGoM), an area especially vulnerable to SLR, the abundance and distribution of SAV food resources (seeds, rhizomes, and tissue) can influence the carrying capacity of coastal marshes to support wintering waterfowl. Despite the known importance of SAV little is known about their distribution across coastal landscapes and salinity zones or how they may be impacted by SLR. We estimated SAV cover and seed biomass in coastal marshes from Texas to Alabama from 1 June – 15 September 2013 to assess variation in SAV and seed resource distribution and abundance across the salinity gradient. Percent cover of SAV was similar among salinity zones (10%–20%) although patterns of distribution differed. Specifically, SAV occurred less frequently in saline zones, but when present the percent coverage was greater than in fresh, intermediate and brackish. Mean seed biomass varied greatly and did not differ significantly among salinity zones. However, when considering only seed species identified as waterfowl foods, the mean seed biomass was lower in saline zones (1.2 g m–2). Alteration of nGoM marshes due to SLR will likely shift the distribution and abundance of SAV resources, and these shifts may affect carrying capacity of coastal marshes for waterfowl and other associated species.

  11. Predictive models of turbidity and water depth in the Doñana marshes using Landsat TM and ETM+ images.

    Science.gov (United States)

    Bustamante, Javier; Pacios, Fernando; Díaz-Delgado, Ricardo; Aragonés, David

    2009-05-01

    We have used Landsat-5 TM and Landsat-7 ETM+ images together with simultaneous ground-truth data at sample points in the Doñana marshes to predict water turbidity and depth from band reflectance using Generalized Additive Models. We have point samples for 12 different dates simultaneous with 7 Landsat-5 and 5 Landsat-7 overpasses. The best model for water turbidity in the marsh explained 38% of variance in ground-truth data and included as predictors band 3 (630-690 nm), band 5 (1550-1750 nm) and the ratio between bands 1 (450-520 nm) and 4 (760-900 nm). Water turbidity is easier to predict for water bodies like the Guadalquivir River and artificial ponds that are deep and not affected by bottom soil reflectance and aquatic vegetation. For the latter, a simple model using band 3 reflectance explains 78.6% of the variance. Water depth is easier to predict than turbidity. The best model for water depth in the marsh explains 78% of the variance and includes as predictors band 1, band 5, the ratio between band 2 (520-600 nm) and band 4, and bottom soil reflectance in band 4 in September, when the marsh is dry. The water turbidity and water depth models have been developed in order to reconstruct historical changes in Doñana wetlands during the last 30 years using the Landsat satellite images time series.

  12. Utilization of invasive tamarisk by salt marsh consumers.

    Science.gov (United States)

    Whitcraft, Christine R; Levin, Lisa A; Talley, Drew; Crooks, Jeffrey A

    2008-11-01

    Plant invasions of coastal wetlands are rapidly changing the structure and function of these systems globally. Alteration of litter dynamics represents one of the fundamental impacts of an invasive plant on salt marsh ecosystems. Tamarisk species (Tamarix spp.), which extensively invade terrestrial and riparian habitats, have been demonstrated to enter food webs in these ecosystems. However, the trophic impacts of the relatively new invasion of tamarisk into marine ecosystem have not been assessed. We evaluated the trophic consequences of invasion by tamarisk for detrital food chains in the Tijuana River National Estuarine Research Reserve salt marsh using litter dynamics techniques and stable isotope enrichment experiments. The observations of a short residence time for tamarisk combined with relatively low C:N values indicate that tamarisk is a relatively available and labile food source. With an isotopic (15N) enrichment of tamarisk, we demonstrated that numerous macroinvertebrate taxonomic and trophic groups, both within and on the sediment, utilized 15N derived from labeled tamarisk detritus. Infaunal invertebrate species that took up no or limited 15N from labeled tamarisk (A. californica, enchytraeid oligochaetes, coleoptera larvae) occurred in lower abundance in the tamarisk-invaded environment. In contrast, species that utilized significant 15N from the labeled tamarisk, such as psychodid insects, an exotic amphipod, and an oniscid isopod, either did not change or occurred in higher abundance. Our research supports the hypothesis that invasive species can alter the trophic structure of an environment through addition of detritus and can also potentially impact higher trophic levels by shifting dominance within the invertebrate community to species not widely consumed.

  13. Physical processes affecting turbidity in a tidal marsh across a range of time scales

    Science.gov (United States)

    Arnold, W.; Poindexter, C.

    2016-12-01

    The direction of net suspended sediment flux, whether into or out of a tidal marsh, can determine whether a marsh is aggrading or eroding. Measuring net suspended sediment fluxes or attributing trends in these fluxes to a particular physical processes is challenging because suspended sediment concentrations are highly variable in time. We used singular spectrum analysis for time series with missing data (SSAM) to observe the relative effects on turbidity of physical processes occurring on different time scales at the Rush Ranch Open Space Preserve. This Preserve covers the largest contiguous area of full-tidal marsh remaining within Suisun Bay, the eastern most subembayment of San Francisco Bay. A long-term monitoring station at First Mallard Slough within the Preserve measures turbidity. Our analysis of of this turbidity record isolated the contribution to total variance from different tides and from annual cycles of San Francisco Bay freshwater inflow, sediment deposition and wind-driven sediment resuspension. Surprisingly, the contribution from diurnal and semidiurnal tidal constituents (30%) was smaller than the contribution from annual cycles of freshwater inflow, sediment deposition and resuspension (38%). This result contrasts with the original implementation of SSAM to suspended sediment concentration, which was conducted in the central San Francisco Bay. This previous work indicated a significant yet smaller contribution (13%) to total suspended sediment concentration variance from annual cycles (Schoellhamer, D. H., 2002, Continental Shelf Research., 22, 1857-1866). The reason for the contrast relates in part to the location of the First Mallard Slough more than 10 km along the tidal channel network from Suisun Bay. At this location, the lowest frequency variation in suspended sediment is accentuated. Annual peaks in turbidity at First Mallard depend not only on spring and summer wind-driven resuspension of sediment in San Pablo Bay but also its co

  14. Hydrocarbon Degradation and Sulfate Reduction in a Coastal Marsh of North Florida

    Science.gov (United States)

    Hsieh, Y.; Bugna, G. C.; Robinson, L.

    2001-05-01

    Hydrocarbon contamination of coastal waters has been an environmental concern for sometime. Coastal wetlands, which are rich in organic matter and microbial activities, have been considered natural systems that could degrade hydrocarbon in contaminated coastal waters. This study was initiated to investigate the potential of hydrocarbon degradation in a coastal salt marsh of North Florida with special reference to sulfate reduction. Freshly collected surface marsh sediments (0-20 cm) were incubated in a laboratory at ambient temperature (23.2° C) with the treatments of: 1) Control (i.e., no treatment), 2) +(crude) oil, 3) +NO3-1+oil, and 4) +MoO4-2+oil. Carbon dioxide evolution from the incubation was collected and analyzed for the total amount and the 13C signature. The NO3-1 and MoO4-2 treatments were intended to block the sulfate reduction activity. The results show that the indigenous organic matter and the crude oil have distinct δ 13C values of -19.8 and -27.6 \\permil, respectively, relative to PDB. Evolved CO2 concentrations and δ 13C values also indicate that microbial populations can adapt to the presence of anthropogenic hydrocarbons. Blocking of sulfate reducers by MoO4-2 addition started to reduce the carbon dioxide evolution rates after a 4-d incubation. After a 48-d incubation, the carbon dioxide evolution of the MoO4-2-treated samples was reduced to only 23 % of the non-MoO4-2-treated samples, indicating the increased significant role of sulfate reducers in digesting older soil organic matter and the hydrocarbons. T-tests also indicated that in NO3-1 treatment, δ 13C values significantly depleted (p=0.1) while CO2 concentration remained relatively constant. These indicate that while denitrifiers played a role in the degradation, the microbial population is predominantly composed of sulfate reducers. Salt marshes would be a much more significant source of CH4 if SO4-2 is suppressed. All MoO4-2-treated samples produced significant amount of methane

  15. A chronology of hurricane landfalls at Little Sippewissett Marsh, Massachusetts, USA, using optical dating

    DEFF Research Database (Denmark)

    Madsen, Anni Tindahl; Duller, G.A.T.; Donnelly, J.P.

    2009-01-01

    Optical dating has been applied to sediments preserved in Little Sippewissett Marsh, Massachusetts, USA, which are associated with overwashing of the beach barrier during hurricane strikes on the coast. The aims were to determine the hurricane landfall frequency, and make comparisons with indepen...

  16. Perceptions of Psychological Coercion and Human Trafficking in the West Midlands of England: Beginning to Know the Unknown

    Science.gov (United States)

    Dando, Coral J.; Walsh, David; Brierley, Robin

    2016-01-01

    Modern slavery is less overt than historical state-sanctioned slavery because psychological abuse is typically used to recruit and then control victims. The recent UK Draft Modern Slavery Bill, and current UK government anti-slavery strategy relies heavily on a shared understanding and public cooperation to tackle this crime. Yet, UK research investigating public understanding of modern slavery is elusive. We report community survey data from 682 residents of the Midlands of England, where modern slavery is known to occur, concerning their understanding of nonphysical coercion and human trafficking (one particular form of modern slavery). Analysis of quantitative data and themed categorization of qualitative data revealed a mismatch between theoretical frameworks and understanding of psychological coercion, and misconceptions concerning the nature of human trafficking. Many respondents did not understand psychological coercion, believed that human trafficking did not affect them, and confused trafficking with immigration. The public are one of the most influential interest groups, but only if well informed and motivated towards positive action. Our findings suggest the need for strategically targeted public knowledge exchange concerning this crime. PMID:27149330

  17. Perceptions of Psychological Coercion and Human Trafficking in the West Midlands of England: Beginning to Know the Unknown.

    Science.gov (United States)

    Dando, Coral J; Walsh, David; Brierley, Robin

    2016-01-01

    Modern slavery is less overt than historical state-sanctioned slavery because psychological abuse is typically used to recruit and then control victims. The recent UK Draft Modern Slavery Bill, and current UK government anti-slavery strategy relies heavily on a shared understanding and public cooperation to tackle this crime. Yet, UK research investigating public understanding of modern slavery is elusive. We report community survey data from 682 residents of the Midlands of England, where modern slavery is known to occur, concerning their understanding of nonphysical coercion and human trafficking (one particular form of modern slavery). Analysis of quantitative data and themed categorization of qualitative data revealed a mismatch between theoretical frameworks and understanding of psychological coercion, and misconceptions concerning the nature of human trafficking. Many respondents did not understand psychological coercion, believed that human trafficking did not affect them, and confused trafficking with immigration. The public are one of the most influential interest groups, but only if well informed and motivated towards positive action. Our findings suggest the need for strategically targeted public knowledge exchange concerning this crime.

  18. Co‐occurrence dynamics of endangered Lower Keys marsh rabbits and free‐ranging domestic cats: Prey responses to an exotic predator removal program

    Science.gov (United States)

    Cove, Michael V.; Gardner, Beth; Simons, Theodore R.; O'Connell, Allan F.

    2018-01-01

    The Lower Keys marsh rabbit (Sylvilagus palustris hefneri) is one of many endangered endemic species of the Florida Keys. The main threats are habitat loss and fragmentation from sea‐level rise, development, and habitat succession. Exotic predators such as free‐ranging domestic cats (Felis catus) pose an additional threat to these endangered small mammals. Management strategies have focused on habitat restoration and exotic predator control. However, the effectiveness of predator removal and the effects of anthropogenic habitat modifications and restoration have not been evaluated. Between 2013 and 2015, we used camera traps to survey marsh rabbits and free‐ranging cats at 84 sites in the National Key Deer Refuge, Big Pine Key, Florida, USA. We used dynamic occupancy models to determine factors associated with marsh rabbit occurrence, colonization, extinction, and the co‐occurrence of marsh rabbits and cats during a period of predator removal. Rabbit occurrence was positively related to freshwater habitat and patch size, but was negatively related to the number of individual cats detected at each site. Furthermore, marsh rabbit colonization was negatively associated with relative increases in the number of individual cats at each site between survey years. Cat occurrence was negatively associated with increasing distance from human developments. The probability of cat site extinction was positively related to a 2‐year trapping effort, indicating that predator removal reduced the cat population. Dynamic co‐occurrence models suggested that cats and marsh rabbits co‐occur less frequently than expected under random conditions, whereas co‐detections were site and survey‐specific. Rabbit site extinction and colonization were not strongly conditional on cat presence, but corresponded with a negative association. Our results suggest that while rabbits can colonize and persist at sites where cats occur, it is the number of individual cats at a site that

  19. Co-occurrence dynamics of endangered Lower Keys marsh rabbits and free-ranging domestic cats: Prey responses to an exotic predator removal program.

    Science.gov (United States)

    Cove, Michael V; Gardner, Beth; Simons, Theodore R; O'Connell, Allan F

    2018-04-01

    The Lower Keys marsh rabbit ( Sylvilagus palustris hefneri ) is one of many endangered endemic species of the Florida Keys. The main threats are habitat loss and fragmentation from sea-level rise, development, and habitat succession. Exotic predators such as free-ranging domestic cats ( Felis catus ) pose an additional threat to these endangered small mammals. Management strategies have focused on habitat restoration and exotic predator control. However, the effectiveness of predator removal and the effects of anthropogenic habitat modifications and restoration have not been evaluated. Between 2013 and 2015, we used camera traps to survey marsh rabbits and free-ranging cats at 84 sites in the National Key Deer Refuge, Big Pine Key, Florida, USA. We used dynamic occupancy models to determine factors associated with marsh rabbit occurrence, colonization, extinction, and the co-occurrence of marsh rabbits and cats during a period of predator removal. Rabbit occurrence was positively related to freshwater habitat and patch size, but was negatively related to the number of individual cats detected at each site. Furthermore, marsh rabbit colonization was negatively associated with relative increases in the number of individual cats at each site between survey years. Cat occurrence was negatively associated with increasing distance from human developments. The probability of cat site extinction was positively related to a 2-year trapping effort, indicating that predator removal reduced the cat population. Dynamic co-occurrence models suggested that cats and marsh rabbits co-occur less frequently than expected under random conditions, whereas co-detections were site and survey-specific. Rabbit site extinction and colonization were not strongly conditional on cat presence, but corresponded with a negative association. Our results suggest that while rabbits can colonize and persist at sites where cats occur, it is the number of individual cats at a site that more strongly

  20. Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments

    Science.gov (United States)

    Kearns, Patrick J.; Angell, John H.; Howard, Evan M.; Deegan, Linda A.; Stanley, Rachel H. R.; Bowen, Jennifer L.

    2016-09-01

    Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy.