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Sample records for chesapeake bay usa

  1. Islands at bay: Rising seas, eroding islands, and waterbird habitat loss in Chesapeake Bay (USA)

    Science.gov (United States)

    Erwin, R.M.; Brinker, D.F.; Watts, B.D.; Costanzo, G.R.; Morton, D.D.

    2011-01-01

    Like many resources in the Chesapeake Bay region of the U. S., many waterbird nesting populations have suffered over the past three to four decades. In this study, historic information for the entire Bay and recent results from the Tangier Sound region were evaluated to illustrate patterns of island erosion and habitat loss for 19 breeding species of waterbirds. Aerial imagery and field data collected in the nesting season were the primary sources of data. From 1993/1994 to 2007/2008, a group of 15 islands in Tangier Sound, Virginia were reduced by 21% in area, as most of their small dunes and associated vegetation and forest cover were lost to increased washovers. Concurrently, nesting American black ducks (Anas rubripes) declined by 66%, wading birds (herons-egrets) by 51%, gulls by 72%, common terns (Sterna hirundo) by 96% and black skimmers (Rynchops niger) by about 70% in this complex. The declines noted at the larger Bay-wide scale suggest that this study area maybe symptomatic of a systemic limitation of nesting habitat for these species. The island losses noted in the Chesapeake have also been noted in other Atlantic U. S. coastal states. Stabilization and/or restoration of at least some of the rapidly eroding islands at key coastal areas are critical to help sustain waterbird communities. ?? 2010 US Government.

  2. Climate Change and the Evolution and Fate of the Tangier Islands of Chesapeake Bay, USA

    Science.gov (United States)

    Schulte, David M.; Dridge, Karin M.; Hudgins, Mark H.

    2015-12-01

    Climate change and associated sea level rise (SLR) are already impacting low-lying coastal areas, including islands, throughout the world. Many of these areas are inhabited, many will need to be abandoned in coming decades as SLR continues. We examine the evolution (1850-2013) of the last inhabited offshore island in Virginia waters of Chesapeake Bay USA, the Tangier Islands. Three SLR scenarios, a low, mid, and high, were considered. Since 1850, 66.75% of the islands landmass has been lost. Under the mid-range SLR scenario, much of the remaining landmass is expected to be lost in the next 50 years and the Town will likely need to be abandoned. The high SLR scenario will accelerate the land loss and subsidence, such that the Town may need to be abandoned in as few as 25 years. We propose a conceptual plan that would significantly extend the lifespan of the islands and Town.

  3. Island abandonment and sea-level rise: an historical analog from the Chesapeake Bay, USA

    Energy Technology Data Exchange (ETDEWEB)

    Gibbons, S.J.A. [Wilfrid Laurier University, Waterloo (Canada). Dept. of Geography and Enivronmental Studies; Nicholls, R.J. [University of Southampton (United Kingdom). School of Civil Engineering

    2006-02-15

    Small islands are widely agreed to be vulnerable to human-induced sea-level rise during the 21st century and beyond, with forced abandonment of some low-lying oceanic islands being a real possibility. A regional abandonment of islands in the Chesapeake Bay, USA provides an historical analog of such vulnerability as this has been linked to a mid 19th Century acceleration in relative sea-level rise. Using a case study approach for Holland Island, Maryland, this hypothesis was tested using a range of physical and human historical data. While sea-level rise was the underlying driver, this analysis shows that the abandonment was more complex than a direct response to sea-level rise. Between 1850 and 1900, Holland Island was a booming community and population increased from 37 to 253, with immigration causing the majority of the increase. At the same time, the upland area where people made their homes was steadily diminishing, losing about 15 ha or 38% of the total. After 1900, the island experienced a decrease in population to 169 in 1916, with final abandonment in 1918, with the exception of one family who left by 1920. Final abandonment was triggered by this depopulation as the population fell below a level that could support critical community services, and the community lost faith in their future on Holland Island. It is likely that similar social processes determined the abandonment of the other Chesapeake Bay islands. Looking to the future, it shows that many small low-lying islands could be abandoned due to sea-level rise long before they become physically uninhabitable. (author)

  4. Anatomy of the Chesapeake Bay impact structure revealed by seismic imaging, Delmarva Peninsula, Virginia, USA

    Science.gov (United States)

    Catchings, R.D.; Powars, D.S.; Gohn, G.S.; Horton, J.W., Jr.; Goldman, M.R.; Hole, J.A.

    2008-01-01

    A 30-km-long, radial seismic reflection and refraction survey completed across the northern part of the late Eocene Chesapeake Bay impact structure (CBIS) on the Delmarva Peninsula, Virginia, USA, confirms that the CBIS is a complex central-peak crater. We used a tomographic P wave velocity model and low-fold reflection images, constrained by data from two deep boreholes located on the profile, to interpret the structure and composition of the upper 5 km of crust. The seismic images exhibit well-defined structural features, including (with increasing radial distance) a collapsed central uplift, a breccia-filled moat, and a collapsed transient-crater margin (which collectively constitute a ???40-km-wide collapsed transient crater), and a shallowly deformed annular trough. These seismic images are the first to resolve the deep structure of the crater (>1 km) and the boundaries between the central uplift, moat, and annular trough. Several distinct seismic signatures distinguish breccia units from each other and from more coherent crystalline rocks below the central uplift, moat, and annular trough. Within the moat, breccia extends to a minimum depth of 1.5 km or a maximum of 3.5 km, depending upon the interpretation of the deepest layered materials. The images show ???350 to 500 m of postimpact sediments above the impactites. The imaged structure of the CBIS indicates a complex sequence of event during the cratering process that will provide new constraints for numerical modeling. Copyright 2008 by the American Geophysical Union.

  5. 75 FR 11837 - Chesapeake Bay Watershed Initiative

    Science.gov (United States)

    2010-03-12

    ... Commodity Credit Corporation Chesapeake Bay Watershed Initiative AGENCY: Commodity Credit Corporation and... program funds for the Chesapeake Bay Watershed Initiative. SUMMARY: The Commodity Credit Corporation (CCC... Watershed Initiative for agricultural producers in the Chesapeake Bay watershed in the States of...

  6. A simulation of groundwater discharge and nitrate delivery to chesapeake bay from the lowermost delmarva peninsula, USA

    Science.gov (United States)

    Sanford, W.E.; Pope, J.P.

    2007-01-01

    A groundwater model has been developed for the lowermost Delmarva Peninsula, USA, that simulates saltwater intrusion into local confined aquifers and nitrate delivery to the Chesapeake Bay from the surficial aquifer. A flow path and groundwater-age analysis was performed using the model to estimate the timing of nitrate delivery to the bay over the next several decades. The simulated mean and median residence times of groundwater in the lowermost peninsula are 30 and 15 years, respectively. Current and future nitrate concentrations in coastal groundwater discharge were simulated based on local well data that include nitrate concentrations and groundwater age. A simulated future-trends analysis indicates that nitrate that has been applied to agricultural regions over the last few decades will continue to discharge into the bay for several decades to come. This study highlights the importance of considering the groundwater lag time that affects the mean transport time from diffuse contamination sources.

  7. Modeling the effect of hypoxia on macrobenthos production in the lower Rappahannock River, Chesapeake Bay, USA.

    Directory of Open Access Journals (Sweden)

    Samuel Kersey Sturdivant

    Full Text Available Hypoxia in Chesapeake Bay has substantially increased in recent decades, with detrimental effects on macrobenthic production; the production of these fauna link energy transfer from primary consumers to epibenthic and demersal predators. As such, the development of accurate predictive models that determine the impact of hypoxia on macrobenthic production is important. A continuous-time, biomass-based model was developed for the lower Rappahannock River, a Bay tributary prone to seasonal hypoxia. Phytoplankton, zooplankton, and macrobenthic state variables were modeled, with a focus on quantitatively constraining the effect of hypoxia on macrobenthic biomass. This was accomplished through regression with Z': a sigmoidal function between macrobenthic biomass and dissolved oxygen concentration, derived using macrobenthic data collected from the Rappahannock River during the summers of 2007 and 2008, and applied to compute hypoxia-induced mortality as a rate process. The model was verified using independent monitoring data collected by the Chesapeake Bay Program. Simulations showed that macrobenthic biomass was strongly linked to dissolved oxygen concentrations, with fluctuations in biomass related to the duration and severity of hypoxia. Our model demonstrated that hypoxia negatively affected macrobenthic biomass, as longer durations of hypoxia and greater hypoxic severity resulted in an increasing loss in biomass. This exercise represents an important contribution to modeling anthropogenically impacted coastal ecosystems, by providing an empirically constrained relationship between hypoxia and macrobenthic biomass, and applying that empirical relationship in a mechanistic model to quantify the effect of the severity, duration, and frequency of hypoxia on benthic biomass dynamics.

  8. Modeling the effect of hypoxia on macrobenthos production in the lower Rappahannock River, Chesapeake Bay, USA.

    Science.gov (United States)

    Sturdivant, Samuel Kersey; Brush, Mark J; Diaz, Robert J

    2013-01-01

    Hypoxia in Chesapeake Bay has substantially increased in recent decades, with detrimental effects on macrobenthic production; the production of these fauna link energy transfer from primary consumers to epibenthic and demersal predators. As such, the development of accurate predictive models that determine the impact of hypoxia on macrobenthic production is important. A continuous-time, biomass-based model was developed for the lower Rappahannock River, a Bay tributary prone to seasonal hypoxia. Phytoplankton, zooplankton, and macrobenthic state variables were modeled, with a focus on quantitatively constraining the effect of hypoxia on macrobenthic biomass. This was accomplished through regression with Z': a sigmoidal function between macrobenthic biomass and dissolved oxygen concentration, derived using macrobenthic data collected from the Rappahannock River during the summers of 2007 and 2008, and applied to compute hypoxia-induced mortality as a rate process. The model was verified using independent monitoring data collected by the Chesapeake Bay Program. Simulations showed that macrobenthic biomass was strongly linked to dissolved oxygen concentrations, with fluctuations in biomass related to the duration and severity of hypoxia. Our model demonstrated that hypoxia negatively affected macrobenthic biomass, as longer durations of hypoxia and greater hypoxic severity resulted in an increasing loss in biomass. This exercise represents an important contribution to modeling anthropogenically impacted coastal ecosystems, by providing an empirically constrained relationship between hypoxia and macrobenthic biomass, and applying that empirical relationship in a mechanistic model to quantify the effect of the severity, duration, and frequency of hypoxia on benthic biomass dynamics. PMID:24391904

  9. Chesapeake Bay Program Water Quality Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Chesapeake Information Management System (CIMS), designed in 1996, is an integrated, accessible information management system for the Chesapeake Bay Region....

  10. Wave and Hydrodynamic Modeling for Engineering Design of Jetties at Tangier Island in Chesapeake Bay, USA

    Directory of Open Access Journals (Sweden)

    Lihwa Lin

    2015-12-01

    Full Text Available The protection of a boat canal at the western entrance of Tangier Island, Virginia, located in the lower Chesapeake Bay, is investigated using different structural alternatives. The existing entrance channel is oriented 45 deg with respect to the local shoreline, and exposed directly to the lower Bay without any protection. The adjacent shoreline has experienced progressive erosion in recent decades by flooding due to severe storms and waves. To protect the western entrance of the channel and shoreline, five different jetty and spur combinations were proposed to reduce wave energy in the lee of jetties. Environmental forces affecting the proposed jettied inlet system are quantified using the Coastal Modeling System, consisting of a spectral wave model and a depth-averaged circulation model with sediment transport calculations. Numerical simulations were conducted for design wave conditions and a 50-year return period tropical storm at the project site. Model results show a low crested jetty of 170-m length connecting to the north shore at a 45-deg angle, and a short south spur of 25-m long, provide adequate wave-reduction benefits among the five proposed alternatives. The model simulation indicates this alternative has the minimum impact on sedimentation around the structured inlet and boat canal.

  11. Brominated diphenyl ethers in the sediments, porewater, and biota of the Chesapeake Bay, USA

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K.; Klosterhaus, S.; Liebert, D.; Stapleton, H. [Maryland Univ., Solomons, MD (United States)

    2004-09-15

    Levels of brominated diphenyl ethers (BDEs) are rapidly increasing in the environment, and in a short time these chemicals have evolved from 'emerging contaminants' to globally-distributed organic pollutants. Recent research demonstrates BDEs are sufficiently stable to be transported long distances in the environment and to accumulate in higher trophic levels. Photolysis and metabolism appear to be dominant loss processes for the parent compounds, generating a variety of lower brominated diphenyl ethers, hydroxylated metabolites, and other products. BDEs are hydrophobic, and therefore their transport in aquatic systems is likely controlled by sorption to sediments and perhaps exchange across the air-water interface. To date, few studies have examined the geochemistry of BDEs in natural waters. In this paper, we review our recent measurements of BDEs in the Chesapeake Bay, a shallow, productive estuary in eastern North America. We focus on the distribution of BDE congeners sediment, porewater, and in faunal benthos along a contamination gradient downstream from a wastewater treatment plant and on the spatial distribution of BDEs in bottom-feeding and pelagic fish species.

  12. Effects of forested floodplain soil properties on phosphorous concentrations in two Chesapeake Bay sub-watersheds, Virginia, USA.

    Science.gov (United States)

    Odhiambo, B K; Ricker, M C; Le Blanc, L M; Moxey, K A

    2016-08-01

    Aquatic ecosystems are known to undergo fluctuations in nutrient levels as a result of both natural and anthropogenic processes. Changes in both extrinsic and intrinsic fluvial dynamics necessitate constant monitoring as anthropogenic alterations exert new pressures to previously stable river basins. In this study, we analyzed stream water and riparian zone soil phosphorous (P) dynamics in two third-order sub-watersheds of the lower Chesapeake Bay in Virginia, USA. The Ni River is predominantly forested (70 % forested), and Sugarland Run is a more human impacted (>45 % impervious surfaces) sub-watershed located in the suburbs of Washington D.C. Total stream P concentrations were measured during both high and low flows and Mehlich-3 methods were used to evaluate potential P fluxes in riparian soils. The results show total stream P concentrations in Sugarland Run ranged from 0.002 to 0.20 ppm, with an average of 0.054 ppm. In contrast, the forested Ni River had typical stream P concentrations soil P was significantly higher in the more urbanized Sugarland Run basin (23.8 ± 2.1 ppm) compared to the Ni River basin (16 ± 3.7 ppm). Average stream bank erosion rates and corresponding cut-bank P flux rates were estimated to be 7.98 cm year(-1) and 361 kg P year(-1) for Ni River and 9.84 cm year(-1) and 11,600 kg P year(-1) for Sugarland Run, respectively. The significantly higher values of total P in the stream water and floodplain cut-banks of Sugarland Run suggests erosion and resuspension of previously deposited legacy sediments is an important processes in this human-impacted basin. PMID:27146543

  13. Hydrogeomorphic Regions in the Chesapeake Bay Watershed.

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Generalized lithology (rock type) and physiography based on geologic formations were used to characterize hydrgeomorphic regions (HGMR) within the Chesapeake Bay...

  14. Deriving Chesapeake Bay Water Quality Standards

    Science.gov (United States)

    Tango, Peter J.; Batiuk, Richard A.

    2013-01-01

    Achieving and maintaining the water quality conditions necessary to protect the aquatic living resources of the Chesapeake Bay and its tidal tributaries has required a foundation of quantifiable water quality criteria. Quantitative criteria serve as a critical basis for assessing the attainment of designated uses and measuring progress toward meeting water quality goals of the Chesapeake Bay Program partnership. In 1987, the Chesapeake Bay Program partnership committed to defining the water quality conditions necessary to protect aquatic living resources. Under section 303(c) of the Clean Water Act, States and authorized tribes have the primary responsibility for adopting water quality standards into law or regulation. The Chesapeake Bay Program partnership worked with U.S. Environmental Protection Agency to develop and publish a guidance framework of ambient water quality criteria with designated uses and assessment procedures for dissolved oxygen, water clarity, and chlorophyll a for Chesapeake Bay and its tidal tributaries in 2003. This article reviews the derivation of the water quality criteria, criteria assessment protocols, designated use boundaries, and their refinements published in six addendum documents since 2003 and successfully adopted into each jurisdiction's water quality standards used in developing the Chesapeake Bay Total Maximum Daily Load.

  15. ISOLATION AND DIVERSITY OF ACTINOMYCETES IN THE CHESAPEAKE BAY

    Science.gov (United States)

    Chesapeake Bay was investigated as a source of actinomycetes to creen for production of novel bioactive compounds. he presence of relatively large populations of actinoplanetes, chemotype IID actinomycetes in Chesapeake Bay sediment samples indicates that is an eminently suitable...

  16. Physical property data from the ICDP-USGS Eyreville cores A and B, Chesapeake Bay impact structure, Virginia, USA, acquired using a multisensor core logger

    Science.gov (United States)

    Pierce, H.A.; Murray, J.B.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS) drilled three core holes to a composite depth of 1766 m within the moat of the Chesapeake Bay impact structure. Core recovery rates from the drilling were high (??90%), but problems with core hole collapse limited the geophysical downhole logging to natural-gamma and temperature logs. To supplement the downhole logs, ??5% of the Chesapeake Bay impact structure cores was processed through the USGS GeoTek multisensor core logger (MSCL) located in Menlo Park, California. The measured physical properties included core thickness (cm), density (g cm-3), P-wave velocity (m s-1), P-wave amplitude (%), magnetic susceptibility (cgs), and resistivity (ohm-m). Fractional porosity was a secondary calculated property. The MSCL data-sampling interval for all core sections was 1 cm longitudinally. Photos of each MSCL sampled core section were imbedded with the physical property data for direct comparison. These data have been used in seismic, geologic, thermal history, magnetic, and gravity models of the Chesapeake Bay impact structure. Each physical property curve has a unique signature when viewed over the full depth of the Chesapeake Bay impact structure core holes. Variations in the measured properties reflect differences in pre-impact target-rock lithologies and spatial variations in impact-related deformation during late-stage crater collapse and ocean resurge. ?? 2009 The Geological Society of America.

  17. Detection of erosion events using 10Be profiles: example of the impact of agriculture on soil erosion in the Chesapeake Bay area (U.S.A.)

    Science.gov (United States)

    Valette-Silver, J. N.; Brown, L.; Pavich, M.; Klein, J.; Middleton, R.

    1986-01-01

    10Be concentration, total carbon and grain-size were measured in cores collected in undisturbed estuarine sediments of three tributaries of the Chesapeake Bay. These cores were previously studied by Davis [1] and Brush [2,3] for pollen content, age and sedimentation rate. In this work, we compare the results obtained for these various analyses. In the cores, we observed two increases in 10Be concentration concomitant with two major changes in the pollen composition of the sediments. These two pollen changes each correspond to well-dated agricultural horizons reflecting different stages in the introduction of European farming techniques [2]. In the Chesapeake Bay area, the agricultural development, associated with forest clearing, appears to have triggered the erosion, transport, and sedimentation into the river mouths of large quantities of 10Be-rich soils. This phenomenon explains the observed rise in the sedimentation rate associated with increases in agricultural land-use. ?? 1986.

  18. Polybrominated diphenyl ether flame retardants in Chesapeake Bay region, U.S.A., peregrine falcon (Falco peregrinus) eggs: urban/rural trends.

    Science.gov (United States)

    Potter, Katherine E; Watts, Bryan D; La Guardia, Mark J; Harvey, Ellen P; Hale, Robert C

    2009-05-01

    A total of 23 peregrine falcon (Falco peregrinus) eggs were obtained between 1993 and 2002 from 13 nests, encompassing 11 locations in the Chesapeake Bay region, U.S.A. When multiple eggs were available from the same clutch, average clutch contaminant concentrations were calculated. An overall median total polybrominated diphenyl ether (PBDE) level of 201 ng/g wet weight was determined for the eggs/clutches examined. The maximum in an individual egg, from an urban highway bridge site, was 354 ng/g. This egg also exhibited the highest BDE 209 burden (48.2 ng/g). Compared to distributions reported in fish and piscivorous birds, falcon eggs were enriched in the more brominated congeners. The BDE congeners 153, 99, and 100 constituted 26.0, 24.8, and 13.1%, respectively, of total PBDEs. In most aquatic species, BDE 47 is the most abundant congener reported; however, it constituted only 4.4% of total PBDEs in the eggs of the present study. The median BDE 209 concentration was 6.3 ng/g. The sum of the octa- to nonabrominated congeners (BDEs 196, 197, 206, 207, and 208) contributed, on average, 14.0% of total PBDEs, exceeding the contribution of BDE 209 (5.9%). Concentrations of polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (4,4'-DDE) also were determined in a subset of 16 eggs (collected in 2001-2002 from six nests) and were an order of magnitude greater than the corresponding PBDEs. Median BDE 209 concentrations were significantly correlated (p < 0.01, Spearman R = 0.690) with the human population density of the area surrounding the nest. Total PBDEs, total PCBs, and 4,4'-DDE levels were not correlated to human population density. PMID:19102579

  19. Isolation and Diversity of Actinomycetes in the Chesapeake Bay

    OpenAIRE

    Takizawa, Masayuki; Colwell, Rita R.; Hill, Russell T.

    1993-01-01

    Chesapeake Bay was investigated as a source of actinomycetes to screen for production of novel bioactive compounds. The presence of relatively large populations of actinoplanetes (chemotype II/D actinomycetes) in Chesapeake Bay sediment samples indicates that it is an eminently suitable ecosystem from which to isolate actinomycetes for screening programs. Actinomycetes were isolated from sediment samples collected in Chesapeake Bay with an isolation medium containing nalidixic acid, which pro...

  20. Chesapeake Bay Watershed - Protecting the Chesapeake Bay and its rivers through science, restoration, and partnership

    Science.gov (United States)

    U.S. Geological Survey

    2012-01-01

    The Chesapeake Bay, the Nation's largest estuary, has been degraded due to the impact of human-population increase, which has doubled since 1950, resulting in degraded water quality, loss of habitat, and declines in populations of biological communities. Since the mid-1980s, the Chesapeake Bay Program (CBP), a multi-agency partnership which includes the Department of Interior (DOI), has worked to restore the Bay ecosystem. The U.S. Geological Survey (USGS) has the critical role of providing unbiased scientific information that is utilized to document and understand ecosystem change to help assess the effectiveness of restoration strategies in the Bay and its watershed. The USGS revised its Chesapeake Bay science plan for 2006-2011 to address the collective needs of the CBP, DOI, and USGS with a mission to provide integrated science for improved understanding and management of the Bay ecosystem. The USGS science themes for this mission are: Causes and consequences of land-use change; Impact of climate change and associated hazards; Factors affecting water quality and quantity; Ability of habitat to support fish and bird populations; and Synthesis and forecasting to improve ecosystem assessment, conservation, and restoration.

  1. Endocrine disrupter - estradiol - in Chesapeake Bay tributaries

    Energy Technology Data Exchange (ETDEWEB)

    Dorabawila, Nelum [University of Maryland Eastern Shore, Princess Anne, MD 21853 (United States); Gupta, Gian [University of Maryland Eastern Shore, Princess Anne, MD 21853 (United States)]. E-mail: gcgupta@umes.edu

    2005-04-11

    Exogenous chemicals that interfere with natural hormonal functions are considered endocrine disrupting chemicals (EDCs). Estradiol (17{beta}-estradiol or E2) is the most potent of all xenoestrogens. Induction of vitellogenin (VTG) production in male fish occurs at E2 concentrations as low as 1 ng l{sup -1}. E2 reaches aquatic systems mainly through sewage and animal waste disposal. Surface water samples from ponds, rivers (Wicomico, Manokin and Pocomoke), sewage treatment plants (STPs), and coastal bays (Assawoman, Monie, Chincoteague, and Tangier Sound - Chesapeake Bay) on the Eastern Shore of Maryland were analyzed for E2 using enzyme linked immuno-sorbent assay (ELISA). E2 concentrations in river waters varied between 1.9 and 6.0 ng l{sup -1}. Highest E2 concentrations in river waters were observed immediately downstream of STPs. E2 concentrations in all the coastal bays tested were 2.3-3.2 ng l{sup -1}.

  2. The impact of urban expansion and agricultural legacies on trace metal accumulation in fluvial and lacustrine sediments of the lower Chesapeake Bay basin, USA.

    Science.gov (United States)

    Coxon, T M; Odhiambo, B K; Giancarlo, L C

    2016-10-15

    The progressively declining ecological condition of the Chesapeake Bay is attributed to the influx of contaminants associated with sediment loads supplied by its largest tributaries. The continued urban expansion in the suburbs of Virginia cities, modern agricultural activities in the Shenandoah Valley, the anthropogenic and climate driven changes in fluvial system hydrodynamics and their potential associated impacts on trace metals enrichment in the bay's tributaries necessitate constant environmental monitoring of these important water bodies. Eight (210)Pb and (137)Cs dated sediment cores and seventy two sediment grab samples were used to analyze the spatial and temporal distributions of Al, Ca, Mg, Cr, Cd, As, Se, Pb, Cu, Zn, Mn, and Fe in the waterways of the Virginia portion of the Chesapeake Bay basin. The sediment cores for trace metal historical fluctuation analysis were obtained in lower fluvial-estuarine environments and reservoirs in the upper reaches of the basin. The trace metal profiles revealed high basal enrichment factors (EF) of between 0.05 and 40.24, which are interpreted to represent early nineteenth century agricultural activity and primary resource extraction. Surficial enrichment factors on both cores and surface grab samples ranged from 0.01 (Cu) to 1421 (Cd), with Pb, Cu, Zn, and Cd enrichments a plausible consequence of modern urban expansion and industrial development along major transportation corridors. Contemporary surficial enrichments of As, Se, and Cr also ranged between 0 and 137, with the higher values likely influenced by lithological and atmospheric sources. Pearson correlation analyses suggest mining and agricultural legacies, coupled with aerosol deposition, are responsible for high metal concentrations in western lakes and headwater reaches of fluvial systems, while metal accumulation in estuarine reaches of the major rivers can be attributed to urban effluence and the remobilization of legacy sediments. PMID:27310532

  3. Derivation of habitat-specific dissolved oxygen criteria for Chesapeake Bay and its tidal tributaries

    Science.gov (United States)

    Batiuk, R.A.; Breitburg, D.L.; Diaz, R.J.; Cronin, T. M.; Secor, D.H.; Thursby, G.

    2009-01-01

    The Chesapeake 2000 Agreement committed its state and federal signatories to "define the water quality conditions necessary to protect aquatic living resources" in the Chesapeake Bay (USA) and its tidal tributaries. Hypoxia is one of the key water quality issues addressed as a result of the above Agreement. This paper summarizes the protection goals and specific criteria intended to achieve those goals for addressing hypoxia. The criteria take into account the variety of Bay habitats and the tendency towards low dissolved oxygen in some areas of the Bay. Stressful dissolved oxygen conditions were characterized for a diverse array of living resources of the Chesapeake Bay by different aquatic habitats: migratory fish spawning and nursery, shallow-water, open-water, deep-water, and deep-channel. The dissolved oxygen criteria derived for each of these habitats are intended to protect against adverse effects on survival, growth, reproduction and behavior. The criteria accommodate both spatial and temporal aspects of low oxygen events, and have been adopted into the Chesapeake Bay states - Maryland, Virginia, and Delaware - and the District of Columbia's water quality standards regulations. These criteria, now in the form of state regulatory standards, are driving an array of land-based and wastewater pollution reduction actions across the six-watershed.

  4. Composition and temporal patterns of larval fish communities in Chesapeake and Delaware Bays

    Directory of Open Access Journals (Sweden)

    Filipe Ribeiro

    2015-11-01

    Full Text Available Comparing larval fish assemblages in different estuaries provides insights about the coastal distribution of larval populations, larval transport, and adult spawning locations (Ribeiro et al. 2015. We simultaneously compared the larval fish assemblages entering two Middle Atlantic Bight (MAB estuaries (Delaware Bay and Chesapeake Bay, USA through weekly sampling from 2007 to 2009. In total, 43 taxa (32 families and 36 taxa (24 families were collected in Delaware and Chesapeake Bays, respectively. Mean taxonomic diversity, mean richness, and evenness were generally lower in Delaware Bay. Communities of both bays were dominated by Anchoa spp., Gobiosoma spp., Micropogonias undulatus, and Brevoortia tyrannus; Paralichthys spp. was more abundant in Delaware Bay and Microgobius thalassinus was more abundant in Chesapeake Bay. Inter-annual variation in the larval fish communities was low at both sites, with a relatively consistent composition across years, but strong seasonal (intra-annual variation in species composition occurred in both bays. Two groups were identified in Chesapeake Bay: a ‘winter’ group dominated by shelf-spawned species (e.g. M. undulatus and a ‘summer’ group comprising obligate estuarine species and coastal species (e.g. Gobiosoma spp. and Cynoscion regalis, respectively. In Delaware Bay, 4 groups were identified: a ‘summer’ group of mainly obligate estuarine fishes (e.g. Menidia sp. being replaced by a ‘fall’ group (e.g. Ctenogobius boleosoma and Gobionellus oceanicus; ‘winter’ and ‘spring’ groups were dominated by shelf-spawned (e.g. M. undulatus and Paralichthys spp. and obligate estuarine species (e.g. Leiostomus xanthurus and Pseudopleuronectes americanus, respectively. This study demonstrates that inexpensive and simultaneous sampling in different estuaries provides important insights into the variability in community structure of fish assemblages at large spatial scales.

  5. Impact of Hurricane Irene on Vibrio vulnificus and Vibrio parahaemolyticus concentrations in surface water, sediment and cultured oysters in the Chesapeake Bay, Maryland, USA

    Directory of Open Access Journals (Sweden)

    KristiSShaw

    2014-05-01

    Full Text Available To determine if a storm event (i.e., high winds, large volumes of precipitation could alter concentrations of Vibrio vulnificus and Vibrio parahaemolyticus in aquacultured oysters (Crassostrea virginica and associated surface water and sediment, this study followed a sampling timeline before and after Hurricane Irene impacted the Chesapeake Bay estuary in late August 2011. Aquacultured oysters were sampled from two levels in the water column: surface 0.3 m and near-bottom just above the sediment. Concentrations of each Vibrio spp. and associated virulence genes were measured in oysters with a combination of real-time PCR and most probable number enrichment methods, and in sediment and surface water with real-time PCR. While concentration shifts of each Vibrio species were apparent post-storm, statistical tests indicated no significant change in concentration change for either Vibrio species by location (surface or near bottom oysters or date sampled (oyster tissue, surface water and sediment concentrations. V. vulnificus in oyster tissue was correlated with total suspended solids (r=0.41, p=0.04, and V. vulnificus in sediment was correlated with secchi depth (r=-0.93, p< 0.01, salinity (r=-0.46, p=0.02, tidal height (r=-0.45, p=0.03, and surface water V. vulnificus (r=0.98, p< 0.01. V. parahaemolyticus in oyster tissue did not correlate with environmental measurements, but V. parahaemolyticus in sediment and surface water correlated with several measurements including secchi depth (r=-0.48, p=0.02[sediment]; r=-0.97 p< 0.01[surface water] and tidal height (r=-0.96. p< 0.01[sediment], r=-0.59,p< 0.01 [surface water]. The concentrations of Vibrio spp. were higher in oysters relative to other studies (average V. vulnificus 4x105 MPN g-1, V. parahaemolyticus 1x105 MPN g-1, and virulence-associated genes were detected in most oyster samples. This study provides a first estimate of storm-related Vibrio density changes in oyster tissues, sediment and

  6. Seasonality of Chesapeake Bay bacterioplankton species.

    Science.gov (United States)

    Heidelberg, J F; Heidelberg, K B; Colwell, R R

    2002-11-01

    Bacteria, gamma-subclass of Proteobacteria, Vibrio-Photobacterium, Vibrio vulnificus, Vibrio cholerae-Vibrio mimicus, and Vibrio cincinnatiensis in water samples collected from the Choptank River in Chesapeake Bay from 15 April to 16 December 1996 were enumerated using a fluorescent oligonucleotide direct-counting (FODC) procedure. FODC results obtained using a Bacteria taxon-specific probe ranged from one-third the number of to the same number as that obtained by the acridine orange direct count (AODC) procedure. The abundance of individual taxa (per liter) ranged from 0.25 x 10(10) to 2.6 x 10(10) Bacteria, 0.32 x 10(8) to 3.1 x 10(8) gamma-Proteobacteria, 0.2 x 10(8) to 2.1 x 10(8) Vibrio-Photobacterium, 0.5 x 10(7) to 10 x 10(7) V. vulnificus, 0.2 x 10(6) to 6 x 10(6) V. cholerae-V. mimicus, and 0.5 x 10(5) to 8 x 10(5) V. cincinnatiensis. The occurrence of all taxa monitored in this study was higher in summer; however, these taxa made up a larger proportion of the Bacteria when the water temperature was low. Large fluctuations in species abundance as well as in percent composition of Vibrio-Photobacterium occurred from week to week, indicating that localized blooms of these taxa occur. The cross-Choptank River transect sample profile of V. vulnificus and V. cholerae-V. mimicus varied significantly in abundance, and trans-Choptank River transect samples revealed a patchy distribution. PMID:12406742

  7. Extracting Length and Time Scales of Downstream Suspended Transport from Sediment Budget Data: ~100 to 1000-yr Travel Times from the Appalachians to the Chesapeake Bay, U.S.A

    Science.gov (United States)

    Pizzuto, J. E.; Schenk, E.; Hupp, C. R.; Gellis, A.; Noe, G. B.; Williamson, E.; Karwan, D. L.; O'Neal, M. A.; Marquard, J.; Aalto, R. E.; Newbold, J. D.

    2013-12-01

    Watershed Best Management Practices (BMPs) are often designed to reduce loadings of sediments and particle-borne contaminants, but the temporal lag between BMP implementation and improvement in receiving water quality is difficult to assess because particles spend long periods in storage between transport events. Here we present a theory that describes the downstream movement of suspended sediment particles accounting for the time particles spend in storage based on sediment budget data (by grain-size fraction) and information on particle transit times through storage reservoirs. The theory is used to define a suspended-sediment transport-length scale that describes how far particles are carried during transport events, and to estimate a downstream particle velocity that includes time spent in storage. At five upland watersheds of the mid-Atlantic region of the U.S.A., transport-length scales for silt-clay range from 3.5-76.1 km, while those for sand range from 0.9-139.6 km. Stratigraphic data and radiometric dating for a typical eroding bank section suggest an averaged sediment transit time through floodplain storage of 488 years. Mean sediment velocities for silt-clay range from 0.0072-0.16 km/yr, while those for sand range from 0.0008-0.25 km/yr, 4 to 6 orders of magnitude slower than the velocity of water in the channel. These results suggest lag times of 100-1000 years between BMP implementation and effectiveness in receiving waters such as the Chesapeake Bay (where BMPs are located upstream of the characteristic transport length scale). Many particles likely travel much faster than these average values, so further research is needed to define the range and distribution of transport rates within and across particle sizes.

  8. BOOK REVIEW OF "CHESAPEAKE BAY BLUES: SCIENCE, POLITICS, AND THE STRUGGLE TO SAVE THE BAY"

    Science.gov (United States)

    This is a book review of "Chesapeake Bay Blues: Science, Politics, and the Struggle to Save the Bay". This book is very well written and provides an easily understandable description of the political challenges faced by those proposing new or more stringent environmental regulat...

  9. 33 CFR 207.100 - Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware...

    Science.gov (United States)

    2010-07-01

    ... River to Chesapeake Bay, Del. and Md., between Reedy Point, Delaware River, and Old Town Point Wharf... located at Reedy Point and Old Town Point Wharf. These traffic lights are described in the rules...

  10. Conowingo Reservoir Sedimentation and Chesapeake Bay: State of the Science.

    Science.gov (United States)

    Cerco, Carl F

    2016-05-01

    The Conowingo Reservoir is situated on the Susquehanna River, immediately upstream of Chesapeake Bay, the largest estuary in the United States. Sedimentation in the reservoir provides an unintended benefit to the bay by preventing sediments, organic matter, and nutrients from entering the bay. The sediment storage capacity of the reservoir is nearly exhausted, however, and the resulting increase in loading of sediments and associated materials is a potential threat to Chesapeake Bay water quality. In response to this threat, the Lower Susquehanna River Watershed Assessment was conducted. The assessment indicates the reservoir is in a state of "dynamic equilibrium" in which sediment loads from the upstream watershed to the reservoir are balanced by sediments leaving the reservoir. Increased sediment loads are not a threat to bay water quality. Increased loads of associated organic matter and nutrients are, however, detrimental. Bottom-water dissolved oxygen declines of 0.1 to 0.2 g m are projected as a result of organic matter oxidation and enhanced eutrophication. The decline is small relative to normal variations but results in violations of standards enforced in a recently enacted total maximum daily load. Enhanced reductions in nutrient loads from the watershed are recommended to offset the decline in water quality caused by diminished retention in the reservoir. The assessment exposed several knowledge gaps that require additional investigation, including the potential for increased loading at flows below the threshold for reservoir scour and the nature and reactivity of organic matter and nutrients scoured from the reservoir bottom. PMID:27136154

  11. Field guide to fishes of the chesapeake bay

    CERN Document Server

    Murdy, Edward O.

    2013-01-01

    The only comprehensive field guide to the Chesapeake’s fishes, this book is an indispensable resource for both anglers and students of the Bay. Vivid illustrations by Val Kells complement the expertise of researchers Edward O. Murdy and John A. Musick. They describe fishes that inhabit waters ranging from low-salinity estuaries to the point where the Bay meets the Atlantic Ocean. Key features of this field guide include• full-color illustrations of more than 200 species• text that is presented adjacent to illustrations for easy reference• detailed descriptions of physical characteristics, range, occurrence in the Bay, reproduction, diet, and statistics from fisheries research• spot illustrations that highlight critical features of certain fish• illustrations of juveniles when they look different from adults• appendices that include identification keys Formatted as a compact field guide for students, scientists, researchers, and fishermen, Field Guide to Fishes of the Chesapeake Bay should be a ...

  12. 75 FR 27552 - Guidance for Federal Land Management in the Chesapeake Bay Watershed

    Science.gov (United States)

    2010-05-17

    ... Information Executive Order 13508, Chesapeake Bay Protection and Restoration, dated May 12, 2009 (74 FR 23099... 24, 2010 (75 FR 91294, March 24). This final guidance incorporates revisions resulting from public... AGENCY Guidance for Federal Land Management in the Chesapeake Bay Watershed AGENCY:...

  13. River Flow Control on the Phytoplankton Dynamics of Chesapeake Bay

    Institute of Scientific and Technical Information of China (English)

    YU Qingyun; WANG You; TANG Xuexi; LI Ming

    2013-01-01

    Recent observations support an emerging paradigm that climate variability dominates nutrient enrichment in costal ecosystems,which can explain seasonal and inter-annual variability of phytoplankton community composition,biomass (Chl-a),and primary production (PP).In this paper,we combined observation and modeling to investigate the regulation of phytoplankton dynamics in Chesapeake Bay.The year we chose is 1996 that has high river runoff and is usually called a ‘wet year’.A 3-D physical-biogeochemical model based on ROMS was developed to simulate the seasonal cycle and the regional distributions of phytoplankton biomass and primary production in Chesapeake Bay.Based on the model results,NO3 presents a strong contrast to the river nitrate load during spring and the highest concentration in the bay reaches around 80mmol N m3.Compared with the normal year,phytoplankton bloom in spring of 1996 appears in lower latitudes with a higher concentration.Quantitative comparison between the modeled and observed seasonal averaged dissolved inorganic nitrogen concentrations shows that the model produces reliable results.The correlation coefficient r2 for all quantities exceeds 0.95,and the skill parameter for the four seasons is all above 0.95.

  14. An Economic Evaluation of the Nutrient Assimilation Potential for Commercial Oyster Aquaculture in the Chesapeake Bay

    OpenAIRE

    Miller, Alexander Louis

    2009-01-01

    The Chesapeake Bay states continue to struggle to achieve the water quality goals set out in the Chesapeake Bay Agreement. While policy efforts to combat eutrophication tend to focus on reducing nutrient loads at point and nonpoint sources, waters of the Bay can be improved through an increase in the assimilative capacity of the ecosystem, which would remove nutrients (called nutrient assimilation services) from ambient waters. The filtering capacity of the native oyster, C.virginica, is a wi...

  15. Chesapeake Bay fish–osprey (Pandion haliaetus) food chain: Evaluation of contaminant exposure and genetic damage

    Science.gov (United States)

    Lazarus, Rebecca; Rattner, Barnett A.; McGowan, Peter C.; Hale, Robert C.; Karouna-Reiner, Natalie K.; Erickson, Richard A.; Ottinger, Mary Ann

    2016-01-01

    From 2011 to 2013, a large-scale ecotoxicological study was conducted in several Chesapeake Bay (USA) tributaries (Susquehanna River and flats, the Back, Baltimore Harbor/Patapsco Rivers, Anacostia/ middle Potomac, Elizabeth and James Rivers) and Poplar Island as a mid-Bay reference site. Osprey (Pandion haliaetus) diet and the transfer of contaminants from fish to osprey eggs were evaluated. The most bioaccumulative compounds (biomagnification factor > 5) included p,p′-dichlorodiphenyldichloroethylene (DDE), total polychlorinated biphenyls (PCBs), total polybrominated diphenyl ethers (PBDEs), and bromodiphenyl ether (BDE) congeners 47, 99, 100, and 154. This analysis suggested that alternative brominated flame retardants and other compounds (methoxytriclosan) are not appreciably biomagnifying. A multivariate analysis of similarity indicated that major differences in patterns among study sites were driven by PCB congeners 105, 128, 156, 170/190, and 189, and PBDE congeners 99 and 209. An integrative redundancy analysis showed that osprey eggs from Baltimore Harbor/Patapsco River and the Elizabeth River had high residues of PCBs and p,p′-DDE, with PBDEs making a substantial contribution to overall halogenated contamination on the Susquehanna and Anacostia/middle Potomac Rivers. The redundancy analysis also suggested a potential relation between PBDE residues in osprey eggs and oxidative DNA damage in nestling blood samples. The results also indicate that there is no longer a discernible relation between halogenated contaminants in osprey eggs and their reproductive success in Chesapeake Bay. Osprey populations are thriving in much of the Chesapeake, with productivity rates exceeding those required to sustain a stable population.

  16. Chesapeake Bay fish-osprey (Pandion haliaetus) food chain: Evaluation of contaminant exposure and genetic damage.

    Science.gov (United States)

    Lazarus, Rebecca S; Rattner, Barnett A; McGowan, Peter C; Hale, Robert C; Karouna-Renier, Natalie K; Erickson, Richard A; Ottinger, Mary Ann

    2016-06-01

    From 2011 to 2013, a large-scale ecotoxicological study was conducted in several Chesapeake Bay (USA) tributaries (Susquehanna River and flats, the Back, Baltimore Harbor/Patapsco Rivers, Anacostia/ middle Potomac, Elizabeth and James Rivers) and Poplar Island as a mid-Bay reference site. Osprey (Pandion haliaetus) diet and the transfer of contaminants from fish to osprey eggs were evaluated. The most bioaccumulative compounds (biomagnification factor > 5) included p,p'-dichlorodiphenyldichloroethylene (DDE), total polychlorinated biphenyls (PCBs), total polybrominated diphenyl ethers (PBDEs), and bromodiphenyl ether (BDE) congeners 47, 99, 100, and 154. This analysis suggested that alternative brominated flame retardants and other compounds (methoxytriclosan) are not appreciably biomagnifying. A multivariate analysis of similarity indicated that major differences in patterns among study sites were driven by PCB congeners 105, 128, 156, 170/190, and 189, and PBDE congeners 99 and 209. An integrative redundancy analysis showed that osprey eggs from Baltimore Harbor/Patapsco River and the Elizabeth River had high residues of PCBs and p,p'-DDE, with PBDEs making a substantial contribution to overall halogenated contamination on the Susquehanna and Anacostia/middle Potomac Rivers. The redundancy analysis also suggested a potential relation between PBDE residues in osprey eggs and oxidative DNA damage in nestling blood samples. The results also indicate that there is no longer a discernible relation between halogenated contaminants in osprey eggs and their reproductive success in Chesapeake Bay. Osprey populations are thriving in much of the Chesapeake, with productivity rates exceeding those required to sustain a stable population. Environ Toxicol Chem 2016;35:1560-1575. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US Government work and, as such, is in the public domain in the United States of America. PMID:26822899

  17. National Status and Trends: Bioeffects Assessment Program, Chesapeake Bay Summary Database (1998-2001)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study was based on the sediment quality triad (SQT) approach. A stratified probabilistic sampling design was utilized to characterize the Chesapeake Bay system...

  18. Contaminant exposure and reproductive success of ospreys (Pandion haliaetus) nesting in Chesapeake Bay regions of concern

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Chesapeake Bay osprey population has more than doubled in size since restrictions were placed on the production and use of and other in the 1970s. Ospreys are...

  19. Bald Eagle Movements, Distribution and Abundance on the Northern Chesapeake Bay

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The primary objective of this study was to monitor bald eagle movements and to locate bald eagle intensive use areas on the northern Chesapeake Bay. An important...

  20. Willingness to Pay Survey for Chesapeake Bay Total Maximum Daily Load

    Science.gov (United States)

    A stated preference survey to collect data on households’ use of Chesapeake Bay and its watershed, and of their preferences for a variety of water quality improvements likely to follow from pollution reduction programs.

  1. Multi-band algorithms for the estimation of chlorophyll concentration in the Chesapeake Bay

    KAUST Repository

    Gilerson, Alexander

    2015-10-14

    Standard blue-green ratio algorithms do not usually work well in turbid productive waters because of the contamination of the blue and green bands by CDOM absorption and scattering by non-algal particles. One of the alternative approaches is based on the two- or three band ratio algorithms in the red/NIR part of the spectrum, which require 665, 708, 753 nm bands (or similar) and which work well in various waters all over the world. The critical 708 nm band for these algorithms is not available on MODIS and VIIRS sensors, which limits applications of this approach. We report on another approach where a combination of the 745nm band with blue-green-red bands was the basis for the new algorithms. A multi-band algorithm which includes ratios Rrs(488)/Rrs(551)and Rrs(671)/Rrs(745) and two band algorithm based on Rrs671/Rrs745 ratio were developed with the main focus on the Chesapeake Bay (USA) waters. These algorithms were tested on the specially developed synthetic datasets, well representing the main relationships between water parameters in the Bay taken from the NASA NOMAD database and available literature, on the field data collected by our group during a 2013 campaign in the Bay, as well as NASA SeaBASS data from the other group and on matchups between satellite imagery and water parameters measured by the Chesapeake Bay program. Our results demonstrate that the coefficient of determination can be as high as R2 > 0.90 for the new algorithms in comparison with R2 = 0.6 for the standard OC3V algorithm on the same field dataset. Substantial improvement was also achieved by applying a similar approach (inclusion of Rrs(667)/Rrs(753) ratio) for MODIS matchups. Results for VIIRS are not yet conclusive. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  2. Characterization of toxic impacts on living marine resources in tidal rivers of the Chesapeake Bay

    OpenAIRE

    Fulton, M.H.; Hyland, J. L.; Key, P B; Wirth, E. F.; Balthis, W. L.; Cooksey, C.; K. Chung; Leight, A.K.

    2007-01-01

    In 1999, the Chesapeake Bay Program completed a survey of existing data on chemical contaminants and the potential for bioeffects in 38 tidal river systems of Chesapeake Bay. This review led to the identification of 20 areas for which there were insufficient data to adequately characterize the potential for contaminant bioeffects on the Bay’s living resources. The goal of the present study was to estimate the current status of ecological condition in five of these areas and thus help to...

  3. The Virginia Beach response to implementing the Chesapeake Bay Preservation Area Ordinance

    OpenAIRE

    Butts, Jeffery Hornor

    2010-01-01

    The City of Virginia Beach adopted the Chesapeake Bay Preservation Area Ordinance in November 1990, effective January 1, 1991. This ordinance incorporated the mandated development performance standards written in the Chesapeake Bay Act. The Act required the implementation of these regulations by localities. The Virginia Beach response to implementing these regulations has been satisfactory to meet the requirements of these regulations, and the City is in compliance with these regulations. The...

  4. Chesapeake Bay Impact Structure Deep Drilling Project Completes Coring

    Directory of Open Access Journals (Sweden)

    the Scientific Staff of the Chesapeake Bay Impact Structure Deep Drilling Project

    2006-09-01

    Full Text Available The Chesapeake Bay Impact Structure Deep Drilling Project (CBIS Project completed its coring operations during September–December 2005 and April–May 2006. Cores were collected continuously to a total depth of 1766 m. The recovered section consists of 1322 m of impactites beneath 444 m of post-impact continental shelf sediments.The CBIS Project is a joint venture of the International Continental Scientifi c Drilling Program (ICDP and the U.S. Geological Survey (USGS. Project activities began with a planning workshop in September 2003 attended by sixtythree scientists from ten countries. Field operations began with site preparation in July 2005, and coring began in September 2005. Drilling, Observation and Sampling of theEarth’s Continental Crust (DOSECC was the general contractor for the drilling operations throughout 2005.

  5. Catastrophic anoxia in the chesapeake bay in 1984.

    Science.gov (United States)

    Seliger, H H; Boggs, J A; Biggley, W H

    1985-04-01

    In 1984, four climatic sequences combined to produce what may be a major anoxic catastrophe in the northern Chesapeake Bay, sufficient to severely threaten the major benthic species. These sequences are (i) the highest late-winter streamflow on record from the Susquehanna River watershed; (ii) streamflows from the Susquehanna River for the consecutive months of June, July, and August that are higher by 2 standard deviations than the respective monthly mean values measured over the last 34 years; (iii) a stationary high in August off the Atlantic Coast; and (iv) an absence of strong storm events in summer. An empirical equation is proposed for the prediction of the monthly trend of dissolved oxygen decrease in terms of a temperature-dependent subpycnoclinal respiration and a modified estuarine Richardson number. As of 23 August 1984, the summer pycnocline of the northern bay had eroded upward from its historically recorded depth below 10 meters to an abnormally shallow 5 meters, with higher stratification than in earlier years. Dissolved oxygen concentrations directly below the pycnocline decreased to zero during June, 2 months earlier than for previous wet years. At present, oxygen-deficient waters containing significant concentrations of hydrogen sulfide have penetrated into Eastern Bay and the Choptank and Potomac rivers. Because most remaining shellfish-spawning and seed-bed areas in these tributaries are located at depths between 4 and 8 meters, the continued absence of major destratifying events will prolong the present anoxic trend and may result in high benthic mortalities. PMID:17811570

  6. Transitioning a Chesapeake Bay Ecological Prediction System to Operations

    Science.gov (United States)

    Brown, C.; Green, D. S.; Eco Forecasters

    2011-12-01

    Ecological prediction of the impacts of physical, chemical, biological, and human-induced change on ecosystems and their components, encompass a wide range of space and time scales, and subject matter. They vary from predicting the occurrence and/or transport of certain species, such harmful algal blooms, or biogeochemical constituents, such as dissolved oxygen concentrations, to large-scale ecosystem responses and higher trophic levels. The timescales of ecological prediction, including guidance and forecasts, range from nowcasts and short-term forecasts (days), to intraseasonal and interannual outlooks (weeks to months), to decadal and century projections in climate change scenarios. The spatial scales range from small coastal inlets to basin and global scale biogeochemical and ecological forecasts. The types of models that have been used include conceptual, empirical, mechanistic, and hybrid approaches. This presentation will identify the challenges and progress toward transitioning experimental model-based ecological prediction into operational guidance and forecasting. Recent efforts are targeting integration of regional ocean, hydrodynamic and hydrological models and leveraging weather and water service infrastructure to enable the prototyping of an operational ecological forecast capability for the Chesapeake Bay and its tidal tributaries. A path finder demonstration predicts the probability of encountering sea nettles (Chrysaora quinquecirrha), a stinging jellyfish. These jellyfish can negatively impact safety and economic activities in the bay and an impact-based forecast that predicts where and when this biotic nuisance occurs may help management effects. The issuance of bay-wide nowcasts and three-day forecasts of sea nettle probability are generated daily by forcing an empirical habitat model (that predicts the probability of sea nettles) with real-time and 3-day forecasts of sea-surface temperature (SST) and salinity (SSS). In the first demonstration

  7. 75 FR 14152 - Executive Order 13508; Chesapeake Bay Protection and Restoration Section 502; Guidance for...

    Science.gov (United States)

    2010-03-24

    ...-effective tools and practices that reduce water pollution and requests public comment. The document was... Bay Protection and Restoration, dated May 12, 2009 (74 FR 23099, May 15, 2009), requires the... Chesapeake Bay watershed describing proven, cost-effective tools and practices that reduce water...

  8. Organic Matter Remineralization Predominates Phosphorus Cycling in the Mid-Bay Sediments in the Chesapeake Bay

    Energy Technology Data Exchange (ETDEWEB)

    Sunendra, Joshi R.; Kukkadapu, Ravi K.; Burdige, David J.; Bowden, Mark E.; Sparks, Donald L.; Jaisi, Deb P.

    2015-05-19

    The Chesapeake Bay, the largest and most productive estuary in the US, suffers from varying degrees of water quality issues fueled by both point and non–point source nutrient sources. Restoration of the bay is complicated by the multitude of nutrient sources, their variable inputs and hydrological conditions, and complex interacting factors including climate forcing. These complexities not only restrict formulation of effective restoration plans but also open up debates on accountability issues with nutrient loading. A detailed understanding of sediment phosphorus (P) dynamics enables one to identify the exchange of dissolved constituents across the sediment- water interface and aid to better constrain mechanisms and processes controlling the coupling between the sediments and the overlying waters. Here we used phosphate oxygen isotope ratios (δ18Op) in concert with sediment chemistry, XRD, and Mössbauer spectroscopy on the sediment retrieved from an organic rich, sulfidic site in the meso-haline portion of the mid-bay to identify sources and pathway of sedimentary P cycling and to infer potential feedback effect on bottom water hypoxia and surface water eutrophication. Isotope data indicate that the regeneration of inorganic P from organic matter degradation (remineralization) is the predominant, if not sole, pathway for authigenic P precipitation in the mid-bay sediments. We interpret that the excess inorganic P generated by remineralization should have overwhelmed any bottom-water and/or pore-water P derived from other sources or biogeochemical processes and exceeded saturation with respect to authigenic P precipitation. It is the first research that identifies the predominance of remineralization pathway against remobilization (coupled Fe-P cycling) pathway in the Chesapeake Bay. Therefore, these results are expected to have significant implications for the current understanding of P cycling and benthic-pelagic coupling in the bay, particularly on the

  9. Organic matter remineralization predominates phosphorus cycling in the mid-Bay sediments in the Chesapeake Bay.

    Science.gov (United States)

    Joshi, Sunendra R; Kukkadapu, Ravi K; Burdige, David J; Bowden, Mark E; Sparks, Donald L; Jaisi, Deb P

    2015-05-19

    Chesapeake Bay, the largest and most productive estuary in the U.S., suffers from varying degrees of water quality issues fueled by both point and nonpoint nutrient sources. Restoration of the Bay is complicated by the multitude of nutrient sources, their variable inputs, and complex interaction between imported and regenerated nutrients. These complexities not only restrict formulation of effective restoration plans but also open up debates on accountability issues with nutrient loading. A detailed understanding of sediment phosphorus (P) dynamics provides information useful in identifying the exchange of dissolved constituents across the sediment-water interface as well as helps to better constrain the mechanisms and processes controlling the coupling between sediments and the overlying waters. Here we used phosphate oxygen isotope ratios (δ(18)O(P)) in concert with sediment chemistry, X-ray diffraction, and Mössbauer spectroscopy on sediments retrieved from an organic rich, sulfidic site in the mesohaline portion of the mid-Bay to identify sources and pathway of sedimentary P cycling and to infer potential feedbacks on bottom water hypoxia and surface water eutrophication. Authigenic phosphate isotope data suggest that the regeneration of inorganic P from organic matter degradation (remineralization) is the predominant, if not sole, pathway for authigenic P precipitation in the mid-Bay sediments. This indicates that the excess inorganic P generated by remineralization should have overwhelmed any pore water and/or bottom water because only a fraction of this precipitates as authigenic P. This is the first research that identifies the predominance of remineralization pathway and recycling of P within the Chesapeake Bay. Therefore, these results have significant implications on the current understanding of sediment P cycling and P exchange across the sediment-water interface in the Bay, particularly in terms of the sources and pathways of P that sustain hypoxia

  10. 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. PMID:27467784

  11. Oyster Reef Communities in the Chesapeake Bay. Virginia Institute of Marine Science Educational Series. [CD-ROM].

    Science.gov (United States)

    Harding, Juliana M.; Mann, Roger; Clark, Vicki P.

    This CD-ROM, Oyster Reef Communities in the Chesapeake Bay, describes oyster reefs, reef communities, and their roles in the Chesapeake Bay ecosystem. Detailed descriptions of scientific research methods and techniques used to monitor and describe oyster reef communities as well as applications of the resulting data are provided. The CD-ROM was…

  12. HYPOXIA IN CHESAPEAKE BAY, 1950-2001: LONG-TERM CHANGE IN RELATION TO NUTRIENT LOADING AND RIVER FLOW

    Science.gov (United States)

    A 52-yr record of dissolved oxygen in Chesapeake Bay (1950 to 2001) and a record of nitrate (NO3-) loading by the Susquehanna River spanning a longer period (1903, 1945 to 2001) were assembled to describe the long-term pattern of hypoxia and anoxia in Chesapeake Bay an...

  13. Food habits and distribution of wintering canvasbacks, Aythya valisineria, on Chesapeake Bay

    Science.gov (United States)

    Perry, M.C.; Uhler, F.M.

    1988-01-01

    Baltic clams (Macoma balthica) were the predominant food items of 323 canvasbacks (Aythya valisineria) collected throughout Chesapeake Bay during 1970-1979. Natural vegetation constituted 4% of the food volume. Widgeongrass (Ruppia maritima) and redhead grass (Potamogeton perfoliatus) constituted the greatest percent volume and frequency of occurrence among the plant species, whereas wild celery (Vallisneria americana) constituted only a trace of the food volume. These results contrast with historical records of food habits of canvasbacks in Chesapeake Bay. Canvasback population estimates during the 1970?s were examined to detect annual and seasonal changes in distribution. Linear regression analyses of winter canvasback populations in the bay showed a significant decline in the upper-bay and middle-bay populations, but no significant changes in the lower-bay and Potomac River populations. The changes in winter distribution and abundance of the canvasback appear related to changes in natural food availability, which is the result of altered environmental conditions.

  14. Coesite in suevites from the Chesapeake Bay impact structure

    Science.gov (United States)

    Jackson, John C.; Horton, J. Wright; Chou, I.-Ming; Belkin, Harvey E.

    2016-05-01

    The occurrence of coesite in suevites from the Chesapeake Bay impact structure is confirmed within a variety of textural domains in situ by Raman spectroscopy for the first time and in mechanically separated grains by X-ray diffraction. Microtextures of coesite identified in situ investigated under transmitted light and by scanning electron microscope reveal coesite as micrometer-sized grains (1-3 μm) within amorphous silica of impact-melt clasts and as submicrometer-sized grains and polycrystalline aggregates within shocked quartz grains. Coesite-bearing quartz grains are present both idiomorphically with original grain margins intact and as highly strained grains that underwent shock-produced plastic deformation. Coesite commonly occurs in plastically deformed quartz grains within domains that appear brown (toasted) in transmitted light and rarely within quartz of spheroidal texture. The coesite likely developed by a mechanism of solid-state transformation from precursor quartz. Raman spectroscopy also showed a series of unidentified peaks associated with shocked quartz grains that likely represent unidentified silica phases, possibly including a moganite-like phase that has not previously been associated with coesite.

  15. Novel psychrotolerant picocyanobacteria isolated from Chesapeake Bay in the winter.

    Science.gov (United States)

    Xu, Yongle; Jiao, Nianzhi; Chen, Feng

    2015-08-01

    Picocyanobacteria are major primary producers in the ocean, especially in the tropical or subtropical oceans or during warm seasons. Many "warm" picocyanobacterial species have been isolated and characterized. However, picocyanobacteria in cold environments or cold seasons are much less studied. In general, little is known about the taxonomy and ecophysiology of picocyanobacteria living in the winter. In this study, 17 strains of picocyanobacteria were isolated from Chesapeake Bay, a temperate estuarine ecosystem, during the winter months. These winter isolates belong to five distinct phylogenetic lineages, and are distinct from the picocyanobacteria previously isolated from the warm seasons. The vast majority of the winter isolates were closely related to picocyanobacteria isolated from other cold environments like Arctic or subalpine waters. The winter picocyanobacterial isolates were able to maintain slow growth or prolonged dormancy at 4°C. Interestingly, the phycoerythrin-rich strains outperformed the phycocyanin-rich strains at cold temperature. In addition, winter picocyanobacteria changed their morphology when cultivated at 4°C. The close phylogenetic relationship between the winter picocyanobacteria and the picocyanobacteria living in high latitude cold regions indicates that low temperature locations select specific ecotypes of picocyanobacteria. PMID:26986796

  16. Variable climatic conditions dominate recent phytoplankton dynamics in Chesapeake Bay

    Science.gov (United States)

    Harding, Lawrence W., Jr.; Mallonee, Michael E.; Perry, Elgin S.; Miller, W. David; Adolf, Jason E.; Gallegos, Charles L.; Paerl, Hans W.

    2016-03-01

    Variable climatic conditions strongly influence phytoplankton dynamics in estuaries globally. Our study area is Chesapeake Bay, a highly productive ecosystem providing natural resources, transportation, and recreation for nearly 16 million people inhabiting a 165,000-km2 watershed. Since World War II, nutrient over-enrichment has led to multiple ecosystem impairments caused by increased phytoplankton biomass as chlorophyll-a (chl-a). Doubled nitrogen (N) loadings from 1945–1980 led to increased chl-a, reduced water clarity, and low dissolved oxygen (DO), while decreased N loadings from 1981–2012 suggest modest improvement. The recent 30+ years are characterized by high inter-annual variability of chl-a, coinciding with irregular dry and wet periods, complicating the detection of long-term trends. Here, we synthesize time-series data for historical and recent N loadings (TN, NO2 + NO3), chl-a, floral composition, and net primary productivity (NPP) to distinguish secular changes caused by nutrient over-enrichment from spatio-temporal variability imposed by climatic conditions. Wet years showed higher chl-a, higher diatom abundance, and increased NPP, while dry years showed lower chl-a, lower diatom abundance, and decreased NPP. Our findings support a conceptual model wherein variable climatic conditions dominate recent phytoplankton dynamics against a backdrop of nutrient over-enrichment, emphasizing the need to separate these effects to gauge progress toward improving water quality in estuaries.

  17. Factors influencing best management practice implementation in Virginia's Chesapeake Bay drainage basin

    OpenAIRE

    Lowery, James B.

    1996-01-01

    A survey of farmers was conducted to determine the extent of cost-share and non-costshare BMP implementation and to evaluate the impact of socio-economic variables of the adoption of BMPs in Virginia's Chesapeake Bay drainage basin. Farmers in 67 counties in Virginia were randomly selected using VirGIS land use data and GRASS 4.1. All of the counties included in the study had at least 90 percent of their total land in the Chesapeake Bay drainage basin. Surveys were mailed to ap...

  18. CULTURAL EUTROPHICATION IN THE CHOPTANK AND PATUXENT ESTUARIES OF CHESAPEAKE BAY

    Science.gov (United States)

    The Choptank and Patuxent tributaries of Chesapeake Bay have become eutrophic over the last 50-100 years. Systematic monitoring of nutrient inputs began in ~1970, and there have been 2-5-fold increases in nitrogen (N) and phosphorus (P) inputs during 1970-2004 due to sewage disch...

  19. 3 CFR 13508 - Executive Order 13508 of May 12, 2009. Chesapeake Bay Protection and Restoration

    Science.gov (United States)

    2010-01-01

    ... laws, and to protect and restore the health, heritage, natural resources, and social and economic value... Historic Trail, the Chesapeake Bay Gateways and Watertrails Network, and the Star-Spangled Banner National Historic Trail. PART 8—MONITORING AND DECISION SUPPORT FOR ECOSYSTEM MANAGEMENT Sec. 801. The...

  20. Oyster Reef Communities in the Chesapeake Bay: A Brief Primer. VORTEX: Virginia's Oyster Reef Teaching EXperience.

    Science.gov (United States)

    Harding, Juliana M.; Mann, Roger; Clark, Vicki P.

    This document introduces Virginia's Oyster Reef Teaching EXperience (VORTEX), which is an interdisciplinary program focusing on the importance of oyster reef communities in the Chesapeake Bay ecosystem. The VORTEX program uses field and laboratory experience supported by multimedia instruction. This document presents an overview on the biology of…

  1. Agricultural Pesticides and Selected Degradation Products in Five Tidal Regions and the Mainstem of Chesapeake Bay

    Science.gov (United States)

    Nutrients, sediment, air pollution, and toxics from the water sources and the surrounding airshed are major problems contributing to poor water quality in many regions of the Chesapeake Bay (CB). Toxics are defined as chemicals that may affect the reproduction, development, and ultimately, the surv...

  2. First results of geothermal investigations, Chesapeake Bay impact structure, Eyreville core holes

    Czech Academy of Sciences Publication Activity Database

    Heidinger, P.; Wilhelm, H.; Popov, Y.; Šafanda, Jan; Burkhardt, H.; Mayr, S.

    Boulder : The Geological Society of America , 2009 - (Gohn, G.), s. 931-940 ISBN 978-0-8137-2458-4. - (Special paper. 458) R&D Projects: GA MŠk LA08036 Institutional research plan: CEZ:AV0Z30120515 Keywords : Chesapeake Bay * impact structure * deep borehole * temperature log * geothermal model Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  3. Movements and bioenergetics of canvasbacks wintering in the upper Chesapeake Bay

    OpenAIRE

    David W. Howerter

    1990-01-01

    The movement patterns, range areas and energetics of canvasbacks (Aythya valisineria) wintering in the upper Chesapeake Bay, Maryland, were investigated. Eighty-seven juvenile female canvasbacks were radio-tracked between 30 December 1988 and 25 March 1989. Diurnal time and energy budgets were constructed for a time of day-season matrix for canvasbacks using riverine and main bay habitats. Canvasbacks were very active at night, making regular and often lengthy crepuscular movements (x = 11.7 ...

  4. Magnitude and Extent of Contaminated Sediment and Toxicity in Chesapeake Bay

    OpenAIRE

    Hartwell, S. Ian; Hameedi, Jawed

    2007-01-01

    INTRODUCTION: This report summarizes the results of NOAA's sediment toxicity, chemistry, and benthic community studies in the Chesapeake Bay estuary. As part of the National Status and Trends (NS&T) Program, NOAA has conducted studies to determine the spatial extent and severity of chemical contamination and associated adverse biological effects in coastal bays and estuaries of the United States since 1991. Sediment contamination in U.S. coastal areas is a major environmental issue becaus...

  5. Incentive-Based Land Use Policies and Water Quality in the Chesapeake Bay

    OpenAIRE

    Walls, Margaret; McConnell, Virginia

    2004-01-01

    Abstract The activities conducted on land surrounding the Chesapeake Bay directly affect pollution levels in the Bay, and they do so in complex and varied ways. Policy attention has been focused, for the most part, on modifying these activities within a particular land use category but not on wholesale changes in land use. For example, farmers are encouraged to use “best management practices” (BMPs) that focus on fertilizer use, crop covers, and the like; residential and commercial developers...

  6. Integrated analysis of ecosystem interactions with land use Change: The Chesapeake Bay watershed

    Science.gov (United States)

    Goetz, Scott J.; Jantz, Claire A.; Prince, Stephen D.; Smith, Andrew J.; Varlyguin, Dmitry; Wright, Robb K.

    The Chesapeake Bay is the largest estuary in the United States, encompassed by a watershed extending 168,000 km2 over portions of six states and Washington, D.C. Restoration of the Bay has been the focus of a two-decade regional partnership of local, state and federal agencies, including a network of scientists, politicians and activists interacting through various committees, working groups, and advisory panels. The effectiveness of the restoration effort has been mixed, with both notable successes and failures. The overall health of the Bay has not declined since the restoration was initiated in 1983, but many of the advances have been offset by the pressure of increasing population and exurban sprawl across the watershed. The needs of the Chesapeake Bay Program are many, but the greatest is accurate information on land cover and land use change, primarily to assess the implications for water quality, examine various restoration scenarios, and calibrate spatial models of the urbanization process. We report here on a number of new land cover and land use data products, and associated applications to assist vulnerability assessment, integrated ecosystem analysis, and ultimately Bay restoration. We provide brief overviews of applications to model new residential development, assess losses and vulnerability of resource lands, and identify the factors that disrupt the health of streams in small watersheds. These data products and approaches are being applied by a number of agencies involved with the restoration effort, including the Chesapeake Bay Program's activities focused on living resources, water quality, and sound land use.

  7. In plain sight: the Chesapeake Bay crater ejecta blanket

    Directory of Open Access Journals (Sweden)

    D. L. Griscom

    2012-02-01

    Full Text Available The discovery nearly two decades ago of a 90 km-diameter impact crater below the lower Chesapeake Bay has gone unnoted by the general public because to date all published literature on the subject has described it as "buried". To the contrary, evidence is presented here that the so-called "upland deposits" that blanket ∼5000 km2 of the U.S. Middle-Atlantic Coastal Plain (M-ACP display morphologic, lithologic, and stratigraphic features consistent with their being ejecta from the 35.4 Ma Chesapeake Bay Impact Structure (CBIS and absolutely inconsistent with the prevailing belief that they are of fluvial origin. Specifically supporting impact origin are the facts that (i a 95 %-pure iron ore endemic to the upland deposits of southern Maryland, eastern Virginia, and the District of Columbia has previously been proven to be impactoclastic in origin, (ii this iron ore welds together a small percentage of well-rounded quartzite pebbles and cobbles of the upland deposits into brittle sheets interpretable as "spall plates" created in the interference-zone of the CBIS impact, (iii the predominantly non-welded upland gravels have long ago been shown to be size sorted with an extreme crater-centric gradient far too large to have been the work of rivers, but well explained as atmospheric size-sorted interference-zone ejecta, (iv new evidence is provided here that ~60 % of the non-welded quartzite pebbles and cobbles of the (lower lying gravel member of the upland deposits display planar fractures attributable to interference-zone tensile waves, (v the (overlying loam member of the upland deposits is attributable to base-surge-type deposition, (vi several exotic clasts found in a debris flow topographically below the upland deposits can only be explained as jetting-phase crater ejecta, and (vii an allogenic granite boulder found among the upland deposits is deduced to have been launched into space and sculpted by hypervelocity air friction

  8. RES2DINV Format Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 8, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  9. RES2DINV Format Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 7, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  10. Processed Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 8, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  11. Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 6, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  12. Processed Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 6, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  13. Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 8, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  14. Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 7, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  15. Processed Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 7, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  16. Goddard DEVELOP Students: Using NASA Remote Sensing Technology to Study the Chesapeake Bay Watershed

    Science.gov (United States)

    Moore, Rachel

    2011-01-01

    The DEVELOP National Program is an Earth Science research internship, operating under NASA s Applied Sciences Program. Each spring, summer, and fall, DEVELOP interns form teams to investigate Earth Science related issues. Since the Fall of 2003, Goddard Space Flight Center (GSFC) has been home to one of 10 national DEVELOP teams. In past terms, students completed a variety of projects related to the Applied Sciences Applications of National Priority, such as Public Health, Natural Disasters, Water Resources, and Ecological Forecasting. These projects have focused on areas all over the world, including the United States, Africa, and Asia. Recently, Goddard DEVELOP students have turned their attention to a local environment, the Chesapeake Bay Watershed. The Chesapeake Bay Watershed is a complex and diverse ecosystem, spanning approximately 64,000 square miles. The watershed encompasses parts of six states: Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia, as well as the District of Columbia. The Bay itself is the biggest estuary in the United States, with over 100,000 tributaries feeding into it. The ratio of fresh water to salt water varies throughout the Bay, allowing for a variety of habitats. The Bay s wetlands, marshes, forests, reefs, and rivers support more than 3,600 plant and animal species, including birds, mammals, reptiles, amphibians, fish, and crabs. The Bay is also commercially significant. It is ranked third in the nation in fishery catch, and supplies approximately 500 million pounds of seafood annually. In addition to its abundant flora and fauna, the Chesapeake Bay watershed is home to approximately 16.6 million people, who live and work throughout the watershed, and who use its diverse resources for recreational purposes. Over the past several decades, the population throughout the watershed has increased rapidly, resulting in land use changes, and ultimately decreasing the health of the Chesapeake Bay Watershed. Over the

  17. What drives interannual variability of hypoxia in Chesapeake Bay: Climate forcing versus nutrient loading?

    Science.gov (United States)

    Li, Ming; Lee, Younjoo J.; Testa, Jeremy M.; Li, Yun; Ni, Wenfei; Kemp, W. Michael; Di Toro, Dominic M.

    2016-03-01

    Oxygen depletion in estuaries is a worldwide problem with detrimental effects on many organisms. Although nutrient loading has been stabilized for a number of these systems, seasonal hypoxia persists and displays large year-to-year variations, with larger hypoxic volumes in wetter years and smaller hypoxic volumes in drier years. Data analysis points to climate as a driver of interannual hypoxia variability, but nutrient inputs covary with freshwater flow. Here we report an oxygen budget analysis of Chesapeake Bay to quantify relative contributions of physical and biogeochemical processes. Vertical diffusive flux declines with river discharge, whereas longitudinal advective flux increases with river discharge, such that their total supply of oxygen to bottom water is relatively unchanged. However, water column respiration exhibits large interannual fluctuations and is correlated with primary production and hypoxic volume. Hence, the model results suggest that nutrient loading is the main mechanism driving interannual hypoxia variability in Chesapeake Bay.

  18. Bacteria of the γ-Subclass Proteobacteria Associated with Zooplankton in Chesapeake Bay

    OpenAIRE

    Heidelberg, J. F.; Heidelberg, K. B.; Colwell, R R

    2002-01-01

    The seasonal abundance of γ-subclass Proteobacteria, Vibrio-Photobacterium, Vibrio cholerae-Vibrio mimicus, Vibrio cincinnatiensis, and Vibrio vulnificus in the Choptank River of Chesapeake Bay associated with zooplankton was monitored from April to December 1996. Large (>202-μm) and small (64- to 202-μm) size classes of zooplankton were collected, and the bacteria associated with each of the zooplankton size classes were enumerated by fluorescent oligonucleotide direct count. Large populatio...

  19. The role of power plant atmospheric emissions in the deposition of nitrogen to the Chesapeake Bay

    International Nuclear Information System (INIS)

    The Maryland Power Plant Research Program (PPRP) has sponsored research on several aspects of atmospheric nitrogen emissions, source attribution, deposition estimation and impact assessment since the mid-eighties. The results of these studies will be presented and discussed in the context of power plant emissions control impact on nitrogen loadings to the Chesapeake Bay and watershed. Information needs with respect to power plant contribution and emission control policy will be identified and discussed from the perspective of PPRP

  20. Millennial-scale sustainability of the Chesapeake Bay Native American oyster fishery.

    Science.gov (United States)

    Rick, Torben C; Reeder-Myers, Leslie A; Hofman, Courtney A; Breitburg, Denise; Lockwood, Rowan; Henkes, Gregory; Kellogg, Lisa; Lowery, Darrin; Luckenbach, Mark W; Mann, Roger; Ogburn, Matthew B; Southworth, Melissa; Wah, John; Wesson, James; Hines, Anson H

    2016-06-01

    Estuaries around the world are in a state of decline following decades or more of overfishing, pollution, and climate change. Oysters (Ostreidae), ecosystem engineers in many estuaries, influence water quality, construct habitat, and provide food for humans and wildlife. In North America's Chesapeake Bay, once-thriving eastern oyster (Crassostrea virginica) populations have declined dramatically, making their restoration and conservation extremely challenging. Here we present data on oyster size and human harvest from Chesapeake Bay archaeological sites spanning ∼3,500 y of Native American, colonial, and historical occupation. We compare oysters from archaeological sites with Pleistocene oyster reefs that existed before human harvest, modern oyster reefs, and other records of human oyster harvest from around the world. Native American fisheries were focused on nearshore oysters and were likely harvested at a rate that was sustainable over centuries to millennia, despite changing Holocene climatic conditions and sea-level rise. These data document resilience in oyster populations under long-term Native American harvest, sea-level rise, and climate change; provide context for managing modern oyster fisheries in the Chesapeake Bay and elsewhere around the world; and demonstrate an interdisciplinary approach that can be applied broadly to other fisheries. PMID:27217572

  1. Land subsidence and relative sea-level rise in the southern Chesapeake Bay region

    Science.gov (United States)

    Eggleston, Jack; Pope, Jason

    2013-01-01

    The southern Chesapeake Bay region is experiencing land subsidence and rising water levels due to global sea-level rise; land subsidence and rising water levels combine to cause relative sea-level rise. Land subsidence has been observed since the 1940s in the southern Chesapeake Bay region at rates of 1.1 to 4.8 millimeters per year (mm/yr), and subsidence continues today. This land subsidence helps explain why the region has the highest rates of sea-level rise on the Atlantic Coast of the United States. Data indicate that land subsidence has been responsible for more than half the relative sea-level rise measured in the region. Land subsidence increases the risk of flooding in low-lying areas, which in turn has important economic, environmental, and human health consequences for the heavily populated and ecologically important southern Chesapeake Bay region. The aquifer system in the region has been compacted by extensive groundwater pumping in the region at rates of 1.5- to 3.7-mm/yr; this compaction accounts for more than half of observed land subsidence in the region. Glacial isostatic adjustment, or the flexing of the Earth’s crust in response to glacier formation and melting, also likely contributes to land subsidence in the region.

  2. The Lower Chesapeake Bay LTAR: A coastal urban-agricultural region

    Science.gov (United States)

    Mccarty, G.; Alfieri, J. G.; Cavigelli, M.; Cosh, M. H.; Hapeman, C. J.; Kustas, W. P.; Maul, J.; Mirsky, S.; Pooler, M.; Sadeghi, A. M.; Schomberg, H.; Timlin, D. J.; Rice, C. P.

    2015-12-01

    The Chesapeake Bay, located in the mid-Atlantic region of the U.S., is the largest estuary in North America. The watershed area includes six states from New York to Virginia and is nearly 167,000 km2 in size with more than 150 rivers and streams entering the 300-km Bay main stem. Forested and agricultural lands make up 58 and 22 percent of the land use, respectively. Nearly 9 percent is urban and suburban use, and the watershed is home to over 17 million people. However, the population is expected to reach 19 million by 2025, raising the potential for conflict between the agricultural and urban communities over land and water use and in protecting natural resources, especially in the lower portion of the Chesapeake Bay watershed. The Lower Chesapeake Bay study area, part of the USDA-ARS Long-Term Agroecosystem Research (LTAR) network, will provide much-needed data to support decisions at this critical agriculture-urban interface. Current long-term projects seek to assess the economic, production, and environmental performance of conventional and organic cropping systems and to evaluate the resilience of these systems to climate change. Large-scale studies are being conducted to examine the effects of land-use and landscape characteristics on ecosystem services and on energy, water, nutrient, carbon, and pest dynamics within watersheds. New in-situ measurement and remote sensor technologies are being considered with the expectancy that the data streams will be available on-line and for use in modeling. Results and outcomes of these research efforts will greatly benefit the national LTAR network and will be applicable to other US coastal urban-agricultural regions.

  3. Chesapeake Bay earth science study: interstitial water chemistry-chemical zonation, tributaries study, and trace metals. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hill, J.M.; Blakeslee, P.J.; Conkwright, R.D.; McKeon, G.

    1982-11-01

    The sediments of the Chesapeake Bay constitute a large reservoir of chemical species derived from natural and anthropogenic sources. The behavior of these materials in the estuary is determined by the physiochemical sedimentary environments in which they are found. Three major environments are identified, from the interstitial water chemistry as Northern Bay, Middle Bay, and Southern Bay. The chemical sedimentary environments of five tributaries to the main Bay were sampled for interstitial water. The data indicate the concentration of the metals are greater than coastal seawater and river water, and comparable to concentrations found in municipal waste.

  4. Challenges associated with modeling low-oxygen waters in Chesapeake Bay: a multiple model comparison

    Science.gov (United States)

    Irby, Isaac D.; Friedrichs, Marjorie A. M.; Friedrichs, Carl T.; Bever, Aaron J.; Hood, Raleigh R.; Lanerolle, Lyon W. J.; Li, Ming; Linker, Lewis; Scully, Malcolm E.; Sellner, Kevin; Shen, Jian; Testa, Jeremy; Wang, Hao; Wang, Ping; Xia, Meng

    2016-04-01

    As three-dimensional (3-D) aquatic ecosystem models are used more frequently for operational water quality forecasts and ecological management decisions, it is important to understand the relative strengths and limitations of existing 3-D models of varying spatial resolution and biogeochemical complexity. To this end, 2-year simulations of the Chesapeake Bay from eight hydrodynamic-oxygen models have been statistically compared to each other and to historical monitoring data. Results show that although models have difficulty resolving the variables typically thought to be the main drivers of dissolved oxygen variability (stratification, nutrients, and chlorophyll), all eight models have significant skill in reproducing the mean and seasonal variability of dissolved oxygen. In addition, models with constant net respiration rates independent of nutrient supply and temperature reproduced observed dissolved oxygen concentrations about as well as much more complex, nutrient-dependent biogeochemical models. This finding has significant ramifications for short-term hypoxia forecasts in the Chesapeake Bay, which may be possible with very simple oxygen parameterizations, in contrast to the more complex full biogeochemical models required for scenario-based forecasting. However, models have difficulty simulating correct density and oxygen mixed layer depths, which are important ecologically in terms of habitat compression. Observations indicate a much stronger correlation between the depths of the top of the pycnocline and oxycline than between their maximum vertical gradients, highlighting the importance of the mixing depth in defining the region of aerobic habitat in the Chesapeake Bay when low-oxygen bottom waters are present. Improvement in hypoxia simulations will thus depend more on the ability of models to reproduce the correct mean and variability of the depth of the physically driven surface mixed layer than the precise magnitude of the vertical density gradient.

  5. Weighted Regressions on Time, Discharge, and Season (WRTDS), with an Application to Chesapeake Bay River Inputs.

    Science.gov (United States)

    Hirsch, Robert M; Moyer, Douglas L; Archfield, Stacey A

    2010-10-01

    A new approach to the analysis of long-term surface water-quality data is proposed and implemented. The goal of this approach is to increase the amount of information that is extracted from the types of rich water-quality datasets that now exist. The method is formulated to allow for maximum flexibility in representations of the long-term trend, seasonal components, and discharge-related components of the behavior of the water-quality variable of interest. It is designed to provide internally consistent estimates of the actual history of concentrations and fluxes as well as histories that eliminate the influence of year-to-year variations in streamflow. The method employs the use of weighted regressions of concentrations on time, discharge, and season. Finally, the method is designed to be useful as a diagnostic tool regarding the kinds of changes that are taking place in the watershed related to point sources, groundwater sources, and surface-water nonpoint sources. The method is applied to datasets for the nine large tributaries of Chesapeake Bay from 1978 to 2008. The results show a wide range of patterns of change in total phosphorus and in dissolved nitrate plus nitrite. These results should prove useful in further examination of the causes of changes, or lack of changes, and may help inform decisions about future actions to reduce nutrient enrichment in the Chesapeake Bay and its watershed.Hirsch, Robert M., Douglas L. Moyer, and Stacey A. Archfield, 2010. Weighted Regressions on Time, Discharge, and Season (WRTDS), With an Application to Chesapeake Bay River Inputs. Journal of the American Water Resources Association (JAWRA) 46(5):857-880. DOI: 10.1111/j.1752-1688.2010.00482.x. PMID:22457569

  6. Direct and indirect estimates of natural mortality for Chesapeake Bay blue crab

    Science.gov (United States)

    Hewitt, D.A.; Lambert, D.M.; Hoenig, J.M.; Lipcius, R.N.; Bunnell, D.B.; Miller, T.J.

    2007-01-01

    Analyses of the population dynamics of blue crab Callinectes sapidus have been complicated by a lack of estimates of the instantaneous natural mortality rate (M). We developed the first direct estimates of M for this species by solving Baranov's catch equation for M given estimates of annual survival rate and exploitation rate. Annual survival rates were estimated from a tagging study on adult female blue crabs in Chesapeake Bay, and female-specific exploitation rates for the same stock were estimated by comparing commercial catches with abundances estimated from a dredge survey. We also used eight published methods based on life history parameters to calculate indirect estimates of M for blue crab. Direct estimates of M for adult females in Chesapeake Bay for the years 2002–2004 ranged from 0.42 to 0.87 per year and averaged 0.71 per year. Indirect estimates of M varied considerably depending on life history parameter inputs and the method used. All eight methods yielded values for M between 0.99 and 1.08 per year, and six of the eight methods yielded values between 0.82 and 1.35 per year. Our results indicate that natural mortality of blue crab is higher than previously believed, and we consider M values between 0.7 and 1.1 per year to be reasonable for the exploitable stock in Chesapeake Bay. Remaining uncertainty about Mmakes it necessary to evaluate a range of estimates in assessment models.

  7. Communities recognition in the Chesapeake Bay ecosystem by dynamical clustering algorithms based on different oscillators systems

    CERN Document Server

    Pluchino, Alessandro; Latora, Vito

    2008-01-01

    We have recently introduced an efficient method for the detection and identification of modules in complex networks, based on the de-synchronization properties (dynamical clustering) of phase oscillators. In this paper we apply the dynamical clustering tecnique to the identification of communities of marine organisms living in the Chesapeake Bay food web. We show that our algorithm is able to perform a very reliable classification of the real communities existing in this ecosystem by using different kinds of dynamical oscillators. We compare also our results with those of other methods for the detection of community structures in complex networks.

  8. Food habits of mute swans in the Chesapeake Bay

    Science.gov (United States)

    Perry, M.C.; Osenton, P.C.; Lohnes, E.J.R.

    2004-01-01

    Unlike the tundra swan (Cygnus columbianus) that migrate to the Bay for the winter, the mute swan (Cygnus olor) is a year long resident and therefore has raised concerns among research managers over reports of conflicts with nesting native water birds and the consumption of submerged aquatic vegetation (SAV). Although data on the reduction of SAV by nesting mute swans and their offspring during the spring and summer are limited, food-habits data show that mute swans rely heavily on SAV during these months. Analyses of the gullet and gizzard of mute swans indicate that widgeon grass (Ruppia maritima) and eelgrass (Zostera marina) were the most important food items to mute swans during the winter and spring. Other organisms were eaten by mute swans, but represent small percentages of food. Corn (Zea mays) fed to the swans by Bay residents in late winter probably supplements their limited vegetative food resources at that time of year.

  9. Evolution of sediment plumes in the Chesapeake bay and implications of climate variability.

    Science.gov (United States)

    Zheng, Guangming; DiGiacomo, Paul M; Kaushal, Sujay S; Yuen-Murphy, Marilyn A; Duan, Shuiwang

    2015-06-01

    Fluvial sediment transport impacts fisheries, marine ecosystems, and human health. In the upper Chesapeake Bay, river-induced sediment plumes are generally known as either a monotonic spatial shape or a turbidity maximum. Little is known about plume evolution in response to variation in streamflow and extreme discharge of sediment. Here we propose a typology of sediment plumes in the upper Chesapeake Bay using a 17 year time series of satellite-derived suspended sediment concentration. On the basis of estimated fluvial and wind contributions, we define an intermittent/wind-dominated type and a continuous type, the latter of which is further divided into four subtypes based on spatial features of plumes, which we refer to as Injection, Transport, Temporary Turbidity-Maximum, and Persistent Turbidity-Maximum. The four continuous types exhibit a consistent sequence of evolution within 1 week to 1 month following flood events. We also identify a "shift" in typology with increased frequency of Turbidity-Maximum types before and after Hurricane Ivan (2004), which implies that extreme events have longer-lasting effects upon estuarine suspended sediment than previously considered. These results can serve as a diagnostic tool to better predict distribution and impacts of estuarine suspended sediment in response to changes in climate and land use. PMID:25938877

  10. Reconstructing the rise of recent coastal anoxia; molybdenum in Chesapeake Bay sediments

    Science.gov (United States)

    Adelson, J.M.; Helz, G.R.; Miller, C.V.

    2001-01-01

    Sporadic, direct observations over a 50 yr period inadequately characterize the history of seasonal hypoxia and anoxia in Chesapeake Bay, alarge estuary threatened by eutrophication. Here, we undertake a reconstruction of 20th century oxygen depletion in this estuary using Mo concentrations in 210Pb-dated sediments; Cu concentrations are used to control for anthropogenic influences. Cores from the central channel display mild Mo enrichments above crustal backgrounds (up to 5 ??g/g) and strong Cu enrichments (up to 35 ??g/g). Temporally, Cu enrichment (mostly anthropogenic) began earlier and stabilized in the last two thirds of the 20th century. In contrast, Mo enrichment has grown during the last two thirds of the century. Molybdenum enrichment is mostly hydrogenic, except in a section of the channel that receives additional Mo from erosion of Early Miocene shore deposits. Two geochemical mechanisms promote Mo enrichment: Manganese refluxing concentrates dissolved MoO24- at the sediment-water interface and sulfide substitution into MoO24- produces thiomolybdates, which can be fixed by particles. The Mo enrichment mechanisms operate primarily during periods when bottom waters are anoxic and thiomolybdate formation can occur near the sediment-water interface. This implies a temporal coupling between water-column anoxia and Mo fixation even though fixation occurs only within sediments. The Mo enrichment profiles suggest that Chesapeake Bay has experienced growing O2 depletion since the first half of the 20th century, but especially after 1960. Copyright ?? 2001 Elsevier Science Ltd.

  11. Assessment of best management practices for improvement of dissolved oxygen in Chesapeake Bay estuary.

    Science.gov (United States)

    Wang, P; Batiuk, R; Linker, L; Shenk, G

    2001-01-01

    Two management scenarios, the base case and the full voluntary program implementation scenarios, are simulated with the three-dimensional Chesapeake Bay estuary model package to study the improvement of dissolved oxygen (DO) over the bay in response to the reduction of nutrient loads. The base case scenario is based on the 1985 nutrient management practices and the associated loads from the watershed and airshed to the bay. The full voluntary program implementation scenario is based on an expanded non-point source and point source program applying current technologies in nutrient and sediment management. The implementation of best management practices is assumed to be by voluntary participation, encouraged by a maximum 75% cost share by the states. The ten-year average (1985-1994) total nitrogen and total phosphorus loads to the bay are reduced 40% and 47%, respectively, from the base case to the full voluntary program implementation scenario. The average annual anoxia and hypoxia volume day is reduced 62% and 42%, respectively, in the whole bay. Daily development of bottom DO in the estuary is observed from an MPEG movie. Graphics of daily DO concentration and depth profile show a significant improvement in DO under improved nutrient control. PMID:11724485

  12. Redox dynamics in the Chesapeake Bay: The effect on sediment/water uranium exchange

    International Nuclear Information System (INIS)

    The effect of seasonal variations in productivity and redox dynamics on the sediment/water exchange of uranium was investigated on a twelve cruise time series in the Chesapeake Bay. The deep waters of the bay undergo seasonal anoxia in response to high primary productivity and water column stratification from late spring to early fall. Dissolved oxygen was used to monitor sediment redox conditions. Dissolved 238U was measured in the water column and sediment porewaters to monitor water column/sediment exchange. Uranium incorporation in bay sediments results from two distinct processes: productivity-dependent scavenging from the water column and redox-dependent cycling of uranium between sediments and bottomwater. Uranium is removed from surface waters of the bay by scavenging with biodetritus during periods of high primary productivity. Bottomwater and sediment redox conditions determine whether this particle-bound uranium is buried or released to overlying water. Particulate uranium is released to bottomwaters and porewaters during the degradation of biodetritus and oxidation of authigenic uranium. Low oxygen in bottomwaters in the summer results in minimal exchange of uranium between the sediments and bottomwater, due to the stability of reduced U(IV). High bottomwater oxygen concentrations associated with bay turnover in the fall results in release of authigenic uranium by oxidation to the soluble (VI) form. Enrichment of uranium in fall bottomwater suggests that authigenic uranium is very labile when exposed to oxic environmental conditions. This process is enhanced by physical mixing when anoxic sediments are resuspended into the oxic bottomwaters

  13. 33 CFR 165.501 - Chesapeake Bay entrance and Hampton Roads, VA and adjacent waters-Regulated Navigation Area.

    Science.gov (United States)

    2010-07-01

    ...) Definitions. In this section: CBBT means the Chesapeake Bay Bridge Tunnel. Coast Guard Patrol Commander is a... patrol vessels shall display the Coast Guard Ensign at all times when underway. I-664 Bridge Tunnel means the Monitor Merrimac Bridge Tunnel. Inland waters means waters within the COLREGS Line of...

  14. Uncertainty in model predictions of Vibrio vulnificus response to climate variability and change: a Chesapeake Bay case study.

    Directory of Open Access Journals (Sweden)

    Erin A Urquhart

    Full Text Available The effect that climate change and variability will have on waterborne bacteria is a topic of increasing concern for coastal ecosystems, including the Chesapeake Bay. Surface water temperature trends in the Bay indicate a warming pattern of roughly 0.3-0.4°C per decade over the past 30 years. It is unclear what impact future warming will have on pathogens currently found in the Bay, including Vibrio spp. Using historical environmental data, combined with three different statistical models of Vibrio vulnificus probability, we explore the relationship between environmental change and predicted Vibrio vulnificus presence in the upper Chesapeake Bay. We find that the predicted response of V. vulnificus probability to high temperatures in the Bay differs systematically between models of differing structure. As existing publicly available datasets are inadequate to determine which model structure is most appropriate, the impact of climatic change on the probability of V. vulnificus presence in the Chesapeake Bay remains uncertain. This result points to the challenge of characterizing climate sensitivity of ecological systems in which data are sparse and only statistical models of ecological sensitivity exist.

  15. Uncertainty in Model Predictions of Vibrio Vulnificus Response to Climate Variability and Change: A Chesapeake Bay Case Study

    Science.gov (United States)

    Urquhart, Erin A.; Zaitchik, Benjamin F.; Waugh, Darryn W.; Guikema, Seth D.; Del Castillo, Carlos E.

    2014-01-01

    The effect that climate change and variability will have on waterborne bacteria is a topic of increasing concern for coastal ecosystems, including the Chesapeake Bay. Surface water temperature trends in the Bay indicate a warming pattern of roughly 0.3-0.4 C per decade over the past 30 years. It is unclear what impact future warming will have on pathogens currently found in the Bay, including Vibrio spp. Using historical environmental data, combined with three different statistical models of Vibrio vulnificus probability, we explore the relationship between environmental change and predicted Vibrio vulnificus presence in the upper Chesapeake Bay. We find that the predicted response of V. vulnificus probability to high temperatures in the Bay differs systematically between models of differing structure. As existing publicly available datasets are inadequate to determine which model structure is most appropriate, the impact of climatic change on the probability of V. vulnificus presence in the Chesapeake Bay remains uncertain. This result points to the challenge of characterizing climate sensitivity of ecological systems in which data are sparse and only statistical models of ecological sensitivity exist.

  16. Postimpact deposition in the Chesapeake Bay impact structure: Variations in eustasy, compaction, sediment supply, and passive-aggressive tectonism

    Science.gov (United States)

    Kulpecz, A.A.; Miller, K.G.; Browning, J.V.; Edwards, L.E.; Powars, D.S.; McLaughlin, P.P., Jr.; Harris, A.D.; Feigenson, M.D.

    2009-01-01

    The Eyreville and Exmore, Virginia, core holes were drilled in the inner basin and annular trough, respectively, of the Chesapeake Bay impact structure, and they allow us to evaluate sequence deposition in an impact crater. We provide new high-resolution geochronologic (<1 Ma) and sequence-stratigraphic interpretations of the Exmore core, identify 12 definite (and four possible) postimpact depositional sequences, and present comparisons with similar results from Eyreville and other mid- Atlantic core holes. The concurrence of increases in ??18O with Chesapeake Bay impact structure sequence boundaries indicates a primary glacioeustatic control on deposition. However, regional comparisons show the differential preservation of sequences across the mid-Atlantic margin. We explain this distribution by the compaction of impactites, regional sediment-supply changes, and the differential movement of basement structures. Upper Eocene strata are thin or missing updip and around the crater, but they thicken into the inner basin (and offshore to the southeast) due to rapid crater infilling and concurrent impactite compaction. Oligocene sequences are generally thin and highly dissected throughout the mid-Atlantic region due to sediment starvation and tectonism, except in southeastern New Jersey. Regional tectonic uplift of the Norfolk Arch coupled with a southward decrease in sediment supply resulted in: (1) largely absent Lower Miocene sections around the Chesapeake Bay impact structure compared to thick sections in New Jersey and Delaware; (2) thick Middle Miocene sequences across the Delmarva Peninsula that thin south of the Chesapeake Bay impact structure; and (3) upper Middle Miocene sections that pinch out just north of the Chesapeake Bay impact structure. Conversely, the Upper Miocene-Pliocene section is thick across Virginia, but it is poorly represented in New Jersey because of regional variations in relative subsidence. ?? 2009 The Geological Society of America.

  17. Potential hazards of environmental contaminants to avifauna residing in the Chesapeake Bay Estuary

    Science.gov (United States)

    Rattner, B.A.; McGowan, P.C.

    2007-01-01

    A search of the Contaminant Exposure and Effects-Terrestrial Vertebrates (CEE-TV) database revealed that 70% of the 839 Chesapeake Bay records deal with avian species. Studies conducted on waterbirds in the past 15 years indicate that organochlorine contaminants have declined in eggs and tissues, although p,p?DDE, total polychlorinated biphenyls (PCBs) and coplanar PCB congeners may still exert sublethal and reproductive effects in some locations. There have been numerous reports of avian die-off events related to organophosphorus and carbamate pesticides. More contemporary contaminants (e.g., alkylphenols, ethoxylates, pertluorinated compounds, polybrominated diphenyl ethers) are detectable in bird eggs in the most industrialized portions of the Bay, but interpretation of these data is difficult because adverse effect levels are incompletely known for birds. Two moderate-sized oil spills resulted in the death of several hundred birds, and about 500 smaller spill events occur annually in the watershed. With the exception of lead, concentrations of cadmium, mercury, and selenium in eggs and tissues appear to be below toxic thresholds for waterbirds. Fishing tackle and discarded plastics, that can entangle and kill young and adults, are prevalent in nests in some Bay tributaries. It is apparent that exposure and potential effects of several classes of contaminants (e.g., dioxins, dibenzofurans, rodenticides, pharmaceuticals, personal care products, lead shot, and some metals) have not been systematically examined in the past 15 years, highlighting the need for toxicological evaluation of birds found dead, and perhaps an avian ecotoxicological monitoring program. Although oil spills, spent lead shot, some pesticides, and industrial pollutants occasionally harm Chesapeake avifauna, contaminants no longer evoke the population level effects that were observed in Ospreys (Pandion haliaetus) and Bald Eagles (Haliaeetus leucocephalus) through the 1970s.

  18. Potential hazards of environmental contaminants to avifauna residing in the Chesapeake Bay estuary

    Science.gov (United States)

    Rattner, Barnett A.; McGowan, Peter C.

    2007-01-01

    A search of the Contaminant Exposure and Effects-Terrestrial Vertebrates (CEE-TV) database revealed that 70% of the 839 Chesapeake Bay records deal with avian species. Studies conducted on waterbirds in the past 15 years indicate that organochlorine contaminants have declined in eggs and tissues, although p,p'-DDE, total polychlorinated biphenyls (PCBs) and coplanar PCB congeners may still exert sublethal and reproductive effects in some locations. There have been numerous reports of avian die-off events related to organophosphorus and carbamate pesticides. More contemporary contaminants (e.g., alkylphenols, ethoxylates, perfluorinated compounds, polybrominated diphenyl ethers) are detectable in bird eggs in the most industrialized portions of the Bay, but interpretation of these data is difficult because adverse effect levels are incompletely known for birds. Two moderaterized oil spills resulted in the death of several hundred birds, and about 500 smaller spill events occur annually in the watershed. With the exception of lead, concentrations of cadmium, mercury, and selenium in eggs and tissues appear to be below toxic thresholds for waterbirds. Fishing tackle and discarded plastics, that can entangle and kill young and adults, are prevalent in nests in some Bay tributaries. It is apparent that exposure and potential effects of several classes of contaminants (e.g., dioxins, dibenzofurans, rodenticides, pharmaceuticals, personal care products, lead shot, and some metals) have not been systematically examined in the past 15 years, highlighting the need for toxicological evaluation of birds found dead, and perhaps an avian ecotoxicological monitoring program. Although oil spills, spent lead shot, some pesticides, and industrial pollutants occasionally harm Chesapeake avifauna, contaminants no longer evoke the population level effects that were observed in Ospreys (Pandion haliaetus) and Bald Eagles (Haliaeetus leucocephalus) through the 1970s.

  19. Contaminant exposure and reproductive success of Ospreys (Pandion haliaetus) nesting in Chesapeake Bay regions of concern

    Science.gov (United States)

    Rattner, B.A.; McGowan, P.C.; Golden, N.H.; Hatfield, J.S.; Toschik, P.C.; Lukei, R.F., Jr.; Hale, R.C.; Schmitz-Afonso, I.; Rice, C.P.

    2004-01-01

    The Chesapeake Bay osprey population has more than doubled in size since restrictions were placed on the production and use of DDT and other toxic organochlorine contaminants in the 1970s. Ospreys are now nesting in the most highly polluted portions of the Bay. In 2000 and 2001, contaminant exposure and reproduction were monitored in ospreys nesting in regions of concern, including Baltimore Harbor and the Patapsco River, the Anacostia and middle Potomac rivers, and the Elizabeth River, and a presumed reference site consisting of the South, West, and Rhode rivers. A 'sample egg' from each study nest was collected for contaminant analysis, and the fate of eggs remaining in each nest (n = 14-16/site) was monitored at 7- to 10-day intervals from egg incubation through fledging of young. Ospreys fledged young in regions of concern (observed success: 0.88 -1.53 fledglings/active nest), although productivity was marginal for sustaining local populations in Baltimore Harbor and the Patapsco River and in the Anacostia and middle Potomac rivers. Concentrations of p,p'DDE and many other organochlorine pesticides or metabolites, total PCBs, some arylhydrocarbon receptor-active PCB congeners and polybrominated diphenyl ether congeners, and perfluorooctanesulfonate were often greater in sample eggs from regions of concern compared to the reference site. Nonetheless, logistic regression analyses did not provide evidence linking marginal productivity to p,p' -DDE, total PCBs, or arylhydrocarbon receptor-active PCB congener exposure in regions of concern. In view of the moderate concentrations of total PCBs in eggs from the reference site, concerns related to new and emerging toxicants, and the absence of ecotoxicological data for terrestrial vertebrates in many Bay tributaries, a more thorough spatial evaluation of contaminant exposure in ospreys throughout the Chesapeake may be warranted.

  20. SEG-Y Formatted Seismic-Reflection Profile Data Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  1. Chesapeake Bay, VA/MD (M130) Bathymetric Digital ElevationModel (30 meter resolution) Derived From Source Hydrographic SurveySoundings Collected by NOAA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry for Chesapeake Bay was derived from two hundred ninety-sevensurveys containing 3,178,509 soundings. Thirty-five older, lessaccurate, overlapping surveys...

  2. RES2DINV Format Continuous Resistivity Profile Data Collected in the Potomac River/Chesapeake Bay on Sept. 6, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  3. CLRHSHD_POTO_GEO.TIF: Color-hillshade relief GeoTIFF image of the Potomac River/Chesapeake Bay Area (Geographic, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  4. RESGPSLNS_JD251.SHP: Ship Trackline Along Which Continuous Resistivity Profile (CRP) Data was Collected in the Potomac River/Chesapeake Bay on Sept. 8, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  5. CLRHSHD_POTO.TIF: Color-hillshade relief GeoTIFF image of the Potomac River/Chesapeake Bay Area (UTM, Zone 18, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  6. Bacterioplankton and organic carbon dynamics in the lower mesohaline chesapeake bay.

    Science.gov (United States)

    Jonas, R B; Tuttle, J H

    1990-03-01

    The mesohaline portion of the Chesapeake Bay is subject to annual summertime hypoxia and anoxia in waters beneath the pycnocline. This dissolved oxygen deficit is directly related to salinity-based stratification of the water column in combination with high levels of autochthonously produced organic matter and a very high abundance of metabolically active bacteria. Throughout the water column in the lower, mesohaline part of the bay, between the Potomac and Rappahannock rivers, near the southern limit of the mainstem anoxia, bacterial abundance often exceeded 10 x 10 cells per ml and bacterial production exceeded 7 x 10 cells per liter per day during summer. Bacterial biomass averaged 34% (range, 16 to 126%) of the phytoplankton biomass in summer. These values are equal to or greater than those found farther north in the bay, where the oxygen deficit is more severe. Seasonal variations in bacterial abundance and production were correlated with phytoplankton biomass (lag time, 7 to 14 days), particulate organic carbon and nitrogen, and particulate biochemical oxygen demand in spring; but during summer, they were significantly correlated only with dissolved biochemical oxygen demand. During summer, dissolved biochemical oxygen demand can account for 50 to 60% of the total biochemical oxygen demand throughout the water column and 80% in the bottom waters. There is a clear spring-summer seasonal shift in the production of organic matter and in the coupling of bacteria and autochthonous organic matter. The measurement of dissolved, microbially labile organic matter concentrations is crucial in understanding the trophic dynamics of the lower mesohaline part of the bay. The absolute levels of organic matter in the water column and the bacterial-organic carbon relationships suggest that a lower bay source of organic matter fuels the upper mesohaline bay oxygen deficits. PMID:16348148

  7. Radionuclide distributions and sorption behavior in the Susquehanna--Chesapeake Bay System

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, C.R.; Larsen, I.L.; Lowry, P.D.; McLean, R.I.; Domotor, S.L.

    1989-01-01

    Radionuclides released into the Susquehanna--Chesapeake System from the Three Mile Island, Peach Bottom, and Calvert Cliffs nuclear power plants are partitioned among dissolved, particulate, and biological phases and may thus exist in a number of physical and chemical forms. In this project, we have measured the dissolved and particulate distributions of fallout /sup 137/Cs; reactor-released /sup 137/Cs, /sup 134/Cs, /sup 65/Zn, /sup 60/Co, and /sup 58/Co; and naturally occurring /sup 7/Be and /sup 210/Pb in the lower Susquehanna River and Upper Chesapeake Bay. In addition, we chemically leached suspended particles and bottom sediments in the laboratory to determine radionuclide partitioning among different particulate-sorbing phases to complement the site-specific field data. This information has been used to document the important geochemical processes that affect the transport, sorption, distribution, and fate of reactor-released radionuclides (and by analogy, other trace contaminants) in this river-estuarine system. Knowledge of the mechanisms, kinetic factors, and processes that affect radionuclide distributions is crucial for predicting their biological availability, toxicity, chemical behavior, physical transport, and accumulation in aquatic systems. The results from this project provide the information necessary for developing accurate radionuclide-transport and biological-uptake models. 76 refs., 12 figs.

  8. Evidence for high salinity of Early Cretaceous sea water from the Chesapeake Bay crater

    Science.gov (United States)

    Sanford, Ward E.; Doughten, Michael W.; Coplen, Tyler B.; Hunt, Andrew G.; Bullen, Thomas D.

    2013-01-01

    High salinity groundwater more than 1000 metres deep in the Atlantic Coastal Plain of the United States has been documented in several locations1,2, most recently within the 35 million-year-old Chesapeake Bay impact crater3,4,5. Suggestions for the origin of increased salinity in the crater have included evaporite dissolution6, osmosis6, and evaporation from heating7 associated with the bolide impact. Here we present chemical, isotopic and physical evidence that together indicate that groundwater in the Chesapeake crater is remnant Early Cretaceous North Atlantic (ECNA) seawater. We find that the seawater is likely 100-145 million years old and that it has an average salinity of about 70 per mil, which is twice that of modern seawater and consistent with the nearly closed ECNA basin8. Previous evidence for temperature and salinity levels of ancient oceans have been estimated indirectly from geochemical, isotopic and paleontological analyses of solid materials in deep sediment cores. In contrast, our study identifies ancient seawater in situ and provides a direct estimate of its age and salinity. Moreover, we suggest that it is likely that remnants of ECNA seawater persist in deep sediments at many locations along the Atlantic margin.

  9. Medieval Warm Period, Little Ice Age and 20th century temperature variability from Chesapeake Bay

    Science.gov (United States)

    Cronin, T. M.; Dwyer, G.S.; Kamiya, T.; Schwede, S.; Willard, D.A.

    2003-01-01

    We present paleoclimate evidence for rapid (Ice Age (???1400-1900 AD) and the Medieval Warm Period (???800-1300 AD) possibly related to changes in the strength of North Atlantic thermohaline circulation (THC). Evidence is presented for a long period of sustained regional and North Atlantic-wide warmth with low-amplitude temperature variability between ???450 and 1000 AD. In addition to centennial-scale temperature shifts, the existence of numerous temperature maxima between 2200 and 250 years BP (average ???70 years) suggests that multi-decadal processes typical of the North Atlantic Oscillation (NAO) are an inherent feature of late Holocene climate. However, late 19th and 20th century temperature extremes in Chesapeake Bay associated with NAO climate variability exceeded those of the prior 2000 years, including the interval 450-1000 AD, by 2-3??C, suggesting anomalous recent behavior of the climate system. ?? 2002 Elsevier Science B.V. All rights reserved.

  10. Movements and bioenergetics of canvasbacks wintering in the upper Chesapeake Bay

    Science.gov (United States)

    Howerter, D.W.

    1990-01-01

    The movement patterns, range areas and energetics of canvasbacks (Aythya valisineria) wintering in the upper Chesapeake Bay, Maryland, were investigated. Eighty-seven juvenile female canvasbacks were radio-tracked between 30 December 1988 and 25 March 1989. Diurnal time and energy budgets were constructed for a time of day-season matrix for canvasbacks using riverine and main bay habitats. Canvasbacks were very active at night, making regular and often lengthy crepuscular movements (x = 11.7 km) from near shore habitats during the day to off shore habitats at night. Movement patterns were similar for birds using habitats on the eastern and western shores of the Bay. Canvasbacks had extensive home ranges averaging 14,286 ha, and used an average of 1.97 core areas. Sleeping was the predominant diurnal behavior. Telemetry indicated that canvasbacks actively fed at night. Canvasbacks spent more time in active behaviors (e.g. swimming, alert) on the eastern shore than on the western shore. Similarly, canvasbacks were more active during daytime hours at locations where artificial feeding occurred. Behavioral patterns were only weakly correlated with weather patterns. Canvasbacks appeared to reduce energy expenditure in mid-winter by reducing distances moved, reducing feeding activities and increasing the amount of time spent sleeping. This pattern was observed even though 1988-89 mid-winter weather conditions were very mild.

  11. Role of wetlands in attenuation of storm surges using coastal circulation model (ADCIRC), Chesapeake Bay region

    Science.gov (United States)

    Deb, Mithun; Ferreira, Celso; Lawler, Seth

    2014-05-01

    The Chesapeake Bay, Virginia is subject to storm surge from extreme weather events nearly year-round; from tropical storms and hurricanes during the summer and fall, (e.g., hurricanes Isabel [2003] and Sandy [2012]), and from nor'easters during the winter (e.g., winter storms Nemo and Saturn [2013]). Coastal wetlands can deliver acute fortification against incoming hurricane storm surges. Coastal wetlands and vegetation shape the hydrodynamics of storm surge events by retaining water and slowing the propagation of storm surge, acting as a natural barrier to flooding. Consequently, a precise scheme to quantify the effect of wetlands on coastal surge levels was also prerequisite. Two wetland sites were chosen in the Chesapeake Bay region for detailed cataloging of vegetation characteristics, including: height, stem diameter, and density. A framework was developed combining these wetlands characterizations with numerical simulations. Storms surges were calculated using Coastal circulation model (ADCIRC) coupled to a wave model (SWAN) forced by an asymmetric hurricane vortex model using an unstructured mesh (comprised of 1.8 million nodes) under a High Performance Computing environment. The Hurricane Boundary Layer (HBL) model was used to compute wind and pressure fields for historical tropical storms and for all of the synthetic storms. Wetlands were characterized in the coupled numerical models by bathymetric and frictional resistance. Multiple model simulations were performed using historical hurricane data and hypothetical storms to compare the predicted storm surge inundation resulting from various levels of wetlands expansion or reduction. The results of these simulations demonstrate the efficacy of wetlands in storm surge attenuation and also the outcome will scientifically support planning of wetlands restoration projects with multi-objective benefits for society.

  12. Particle/vapor concentrations and distributions of PAHs in the atmosphere of southern Chesapeake Bay

    International Nuclear Information System (INIS)

    Atmospheric PAH concentrations were measured at four sites characterized as rural (Haven Beach), semiurban (York River), urban (Hampton), and industrialized (Elizabeth River) areas as part of a study to quantify gaseous exchange fluxes across the air-water interface of southern Chesapeake Bay. Aerosol particle-associated PAH concentrations were similar at all sites; however, PAH vapor concentrations in the urban areas were as much as a factor of 50 greater than those at the rural site. Mean total PAH concentrations ranged from 7.87 ng/m3 at the rural site to 92.8 ng/m3 at the urban site. Daily total PAH concentrations ranged from 1.60 to 198 ng/m3. Exponential increases in PAH vapor concentrations with temperature were observed at the non-rural sites, suggesting volatilization from contaminated surfaces during warmer weather; whereas PAH vapor concentrations at the rural Haven Beach site exhibited little seasonal variability. Aerosol particle-associated PAH levels were similar at all sites and increased in winter due to the temperature dependence of vapor-particle partitioning, increased sources from combustion of fossil fuel and wood for home heating, and cold condensation of source vapors to background aerosols as air masses are dispersed to remote regions. Plots of log Kd vs. log Psat,SC1 indicate PAH partitioning is not at equilibrium in rural areas of Southern Chesapeake Bay. In addition, plots of log Kd vs. 1/T for individual PAHs indicate difference particle characteristics or partitioning processes influence particle/vapor distributions at the urban and rural sites

  13. Reproductive health of yellow perch Perca flavescens in selected tributaries of the Chesapeake Bay

    International Nuclear Information System (INIS)

    Reduced recruitment of yellow perch has been noted for a number of years in certain urbanized watersheds (South and Severn Rivers) of the Chesapeake Bay. Other rapidly developing watersheds such as Mattawoman Creek are more recently showing evidence of reduced recruitment of anadromous fishes. In this study, we used a battery of biomarkers to better document the reproductive health of adult yellow perch collected during spring spawning in 2007–2009. Perch were collected in the South and Severn Rivers, Mattawoman Creek and the less developed Choptank and Allen's Fresh watersheds for comparison. Gonadosomatic indices, plasma reproductive hormone concentrations, plasma vitellogenin concentrations and gonad histology were evaluated in mature perch of both sexes. In addition, sperm quantity (cell counts) and quality (total and progressive motility, spermatogenic stage and DNA integrity), were measured in male perch. Many of these biomarkers varied annually and spatially, with some interesting statistical results and trends. Male perch from the Choptank and Allen's Fresh had generally higher sperm counts. In 2008 counts were significantly lower in the perch from the Severn when compared to other sites. The major microscopic gonadal abnormality in males was the proliferation of putative Leydig cells, observed in testes from Severn and less commonly, Mattawoman Creek perch. Observations that could significantly impact egg viability were an apparent lack of final maturation, abnormal yolk and thin, irregular zona pellucida. These were observed primarily in ovaries from Severn, South and less commonly Mattawoman Creek perch. The potential association of these observations with urbanization, impervious surface and chemical contaminants is discussed. - Highlights: ► Reduced recruitment of yellow perch has occurred in urban tributaries of Chesapeake Bay. ► We compared reproductive health biomarkers in perch from two urban, one developing, two less developed watersheds.

  14. Concentrations of metals in blood and feathers of nestling ospreys (Pandion haliaetus) in Chesapeake and Delaware Bays

    Science.gov (United States)

    Rattner, B.A.; Golden, N.H.; Toschik, P.C.; McGowan, P.C.; Custer, T.W.

    2008-01-01

    In 2000, 2001, and 2002, blood and feather samples were collected from 40-45-day-old nestling ospreys (Pandion haliaetus) from Chesapeake Bay and Delaware Bay and River. Concentrations of 18 metals, metalloids, and other elements were determined in these samples by inductively coupled plasma-mass spectroscopy, and Hg concentrations were measured by cold vapor atomic absorption spectroscopy. When compared to concurrent reference areas (South, West, and Rhode Rivers), mean As and Hg concentrations in blood were greater (p nestlings from the highly industrialized Elizabeth River compared to the rural reference area. When compared to the concurrent reference area, mean Al, Ba, Hg, Mn, and Pb concentrations in feathers were substantially greater (p nestlings from northern Delaware Bay and River had greater concentrations (p nestling feathers from Delaware were frequently greater than in the Chesapeake. The present findings and those of related reproductive studies suggest that concentrations of several heavy metals (e.g., Cd, Hg, Pb) in nestling blood and feathers from Chesapeake and Delaware Bays were below toxicity thresholds and do not seem to be affecting chick survival during the nestling period.

  15. Forecasting hypoxia in the Chesapeake Bay and Gulf of Mexico: model accuracy, precision, and sensitivity to ecosystem change

    International Nuclear Information System (INIS)

    Increasing use of ecological models for management and policy requires robust evaluation of model precision, accuracy, and sensitivity to ecosystem change. We conducted such an evaluation of hypoxia models for the northern Gulf of Mexico and Chesapeake Bay using hindcasts of historical data, comparing several approaches to model calibration. For both systems we find that model sensitivity and precision can be optimized and model accuracy maintained within reasonable bounds by calibrating the model to relatively short, recent 3 year datasets. Model accuracy was higher for Chesapeake Bay than for the Gulf of Mexico, potentially indicating the greater importance of unmodeled processes in the latter system. Retrospective analyses demonstrate both directional and variable changes in sensitivity of hypoxia to nutrient loads.

  16. Impact of Environmental Policies on the Adoption of Animal Waste Management Practices in the Chesapeake Bay Watershed

    OpenAIRE

    Savage, Jeff; Ribaudo, Marc

    2012-01-01

    We use data from the ERS-NASS ARMS surveys to compare the use of best management practices on poultry and livestock farms inside the watershed and outside the watershed. Animal operations within the Chesapeake Bay States were found to be adopting some important manure management practices at a greater rate than operations outside the watershed. Adoption was taking place before the implementation of the TMDL, indicating that farmers may have been acting in response to building public pressure ...

  17. Attenuation of Storm Surge Flooding By Wetlands in the Chesapeake Bay: An Integrated Geospatial Framework Evaluating Impacts to Critical Infrastructure

    Science.gov (United States)

    Khalid, A.; Haddad, J.; Lawler, S.; Ferreira, C.

    2014-12-01

    Areas along the Chesapeake Bay and its tributaries are extremely vulnerable to hurricane flooding, as evidenced by the costly effects and severe impacts of recent storms along the Virginia coast, such as Hurricane Isabel in 2003 and Hurricane Sandy in 2012. Coastal wetlands, in addition to their ecological importance, are expected to mitigate the impact of storm surge by acting as a natural protection against hurricane flooding. Quantifying such interactions helps to provide a sound scientific basis to support planning and decision making. Using storm surge flooding from various historical hurricanes, simulated using a coupled hydrodynamic wave model (ADCIRC-SWAN), we propose an integrated framework yielding a geospatial identification of the capacity of Chesapeake Bay wetlands to protect critical infrastructure. Spatial identification of Chesapeake Bay wetlands is derived from the National Wetlands Inventory (NWI), National Land Cover Database (NLCD), and the Coastal Change Analysis Program (C-CAP). Inventories of population and critical infrastructure are extracted from US Census block data and FEMA's HAZUS-Multi Hazard geodatabase. Geospatial and statistical analyses are carried out to develop a relationship between wetland land cover, hurricane flooding, population and infrastructure vulnerability. These analyses result in the identification and quantification of populations and infrastructure in flooded areas that lie within a reasonable buffer surrounding the identified wetlands. Our analysis thus produces a spatial perspective on the potential for wetlands to attenuate hurricane flood impacts in critical areas. Statistical analysis will support hypothesis testing to evaluate the benefits of wetlands from a flooding and storm-surge attenuation perspective. Results from geospatial analysis are used to identify where interactions with critical infrastructure are relevant in the Chesapeake Bay.

  18. Forecasting Ex-Vessel Prices for Hard Blue Crabs in the Chesapeake Bay Region: Individual and Composite Methods

    OpenAIRE

    Michael A. Hudson; Capps, Oral, Jr.

    1984-01-01

    Given the relative importance of the Chesapeake Bay hard blue crab fishery to the U.S. blue crab fishery , this paper analyzes ex-vessel prices for hard blue crabs landed in this region. The purpose is to evaluate alternative methods of forecasting ex-vessel prices for hard blue crabs in the Bay; both individual methods (trend extrapolation, econometric, and time-series) and composite methods. Examining the mean squared errors for the individual methods, the time-series model performs the bes...

  19. Integrating Federal and State data records to report progress in establishing agricultural conservation practices on Chesapeake Bay farms

    Science.gov (United States)

    Hively, W. Dean; Devereux, Olivia H.; Claggett, Peter

    2013-01-01

    In response to the Executive Order for Chesapeake Bay Protection and Restoration (E.O. #13508, May 12, 2009), the U.S. Geological Survey (USGS) took on the task of acquiring and assessing agricultural conservation practice data records for U.S. Department of Agriculture (USDA) programs, and transferred those datasets in aggregated format to State jurisdictional agencies for use in reporting conservation progress to the Chesapeake Bay Program Partnership (CBP Partnership). Under the guidelines and regulations that have been developed to protect and restore water-quality in the Chesapeake Bay, the six State jurisdictions that fall within the Chesapeake Bay watershed are required to report their progress in promoting agricultural conservation practices to the CBP Partnership on an annual basis. The installation and adoption of agricultural best management practices is supported by technical and financial assistance from both Federal and State conservation programs. The farm enrollment data for USDA conservation programs are confidential, but agencies can obtain access to the privacy-protected data if they are established as USDA Conservation Cooperators. The datasets can also be released to the public if they are first aggregated to protect farmer privacy. In 2012, the USGS used its Conservation Cooperator status to obtain implementation data for conservation programs sponsored by the USDA Natural Resources Conservation Service (NRCS) and the USDA Farm Service Agency (FSA) for farms within the Chesapeake Bay watershed. Three jurisdictions (Delaware, Pennsylvania, and West Virginia) used the USGS-provided aggregated dataset to report conservation progress in 2012, whereas the remaining three jurisdictions (Maryland, New York, and Virginia) used jurisdictional Conservation Cooperator Agreements to obtain privacy-protected data directly from the USDA. This report reviews the status of conservation data sharing between the USDA and the various jurisdictions, discusses the

  20. Feasibility Study of Carbon Sequestration Through Reforestation in the Chesapeake Bay Watershed of Virginia

    Energy Technology Data Exchange (ETDEWEB)

    Andy Lacatell; David Shoch; Bill Stanley; Zoe Kant

    2007-03-01

    The Chesapeake Rivers conservation area encompasses approximately 2,000 square miles of agricultural and forest lands in four Virginia watersheds that drain to the Chesapeake Bay. Consulting a time series of classified Landsat imagery for the Chesapeake Rivers conservation area, the project team developed a GIS-based protocol for identifying agricultural lands that could be reforested, specifically agricultural lands that had been without forest since 1990. Subsequent filters were applied to the initial candidate reforestation sites, including individual sites > 100 acres and sites falling within TNC priority conservation areas. The same data were also used to produce an analysis of baseline changes in forest cover within the study period. The Nature Conservancy and the Virginia Department of Forestry identified three reforestation/management models: (1) hardwood planting to establish old-growth forest, (2) loblolly pine planting to establish working forest buffer with hardwood planting to establish an old-growth core, and (3) loblolly pine planting to establish a working forest. To assess the relative carbon sequestration potential of these different strategies, an accounting of carbon and total project costs was completed for each model. Reforestation/management models produced from 151 to 171 tons carbon dioxide equivalent per acre over 100 years, with present value costs of from $2.61 to $13.28 per ton carbon dioxide equivalent. The outcome of the financial analysis was especially sensitive to the land acquisition/conservation easement cost, which represented the most significant, and also most highly variable, single cost involved. The reforestation/management models explored all require a substantial upfront investment prior to the generation of carbon benefits. Specifically, high land values represent a significant barrier to reforestation projects in the study area, and it is precisely these economic constraints that demonstrate the economic additionality

  1. An EOF analysis of HF Doppler radar current measurements of the Chesapeake Bay buoyant outflow

    Science.gov (United States)

    Marmorino, G. O.; Shay, L. K.; Haus, B. K.; Handler, R. A.; Graber, H. C.; Horne, M. P.

    1999-02-01

    Surface currents measured by HF Doppler radar as part of a study of the Chesapeake Bay outflow plume are examined using a 'real-vector' empirical orthogonal function (EOF) analysis (Kaihatu et al., 1998). Based on about 23 days of nearly continuous data, the analysis shows that the first three EOF modes, judged to be the only significant modes, account for 76% of the variance in the data set. The buoyant outflow occurs primarily in the mean flow field. The first EOF mode is dominated by wind forcing and the second mode by across-shelf semi-diurnal tidal forcing. The third mode exhibits a large-scale horizontal shear and contains a curved region of weak relative flow which appears to delineate the offshore edge of the plume; also, the third-mode response varies over the spring-neap cycle, suggesting a modulation of the outflow plume by a tidal residual eddy. The analysis therefore has provided a useful, exploratory examination of this dataset of surface currents.

  2. Urbanization, Forest Vulnerability and Resource Land Loss in the Chesapeake Bay Watershed

    Science.gov (United States)

    Jantz, C.; Goetz, S. J.; Jantz, P.

    2004-12-01

    The contemporary pattern of urban development in industrialized countries is increasingly taking the form of low density, decentralized residential and commercial development. In the Chesapeake Bay watershed, which is located within the mid-Atlantic region of the United States, dispersed development patterns have been linked to habitat fragmentation and declining water quality. Our objectives were to document how this urbanization process has expanded throughout the watershed and to explore how lands comprising the natural resource base, particularly forests, have been replaced by a matrix of the built environment. We accomplished this by mapping impervious surface cover (houses, roads, etc) across the ~168,000 km2 area using a time series of satellite imagery. We calculated metrics of land use change and used these to estimate the loss of resource lands across the region. We conservatively estimate that 334 km2 of forest, 888 km2 of agriculture and 2 km2 of wetlands have been converted to impervious surfaces between 1990 and 2000. We also used the time series to calibrate a spatial model of urban land use change, and forecasted future development patterns in Maryland out to 2030 under different policy scenarios. Using Maryland Department of Natural Resources' (DNR) Strategic Forest Lands Assessment (SFLA), which evaluates forest resources in terms of their economic and ecologic value, and Maryland's Green Infrastructure, which identifies ecologically valuable patches of contiguous forests and wetlands, we evaluated the vulnerability of natural resources in Maryland. Threats associated with loss and fragmentation were identified.

  3. Effects of erosion control structures along a portion of the northern Chesapeake Bay shoreline

    Science.gov (United States)

    Zabawa, C.F.; Kerhin, R.T.; Bayley, S.

    1981-01-01

    A 6.500-meter reach of western Chesapeake Bay shoreline (lower Mayo Peninsula) lost about 1.1??106 cubic meters of sediment (equivalent to 170 cubic meters lost per meter of shoreline) between 1846 and 1932, when the first aerial photographs show the shoreline already substantially protected by a system of groins and intermittent bulkheading. These structures have eliminated the fastland as a source of erodable material, and have starved the supply of sand for littoral drift, thus limiting the extent of the beaches to the remaining groin fields. Volumes of sediment involved in these impacts are small in the overall sediment budget. Bulkheads produce no deficit in the budget since scouring of the beaches on their seaward sides makes up for the decreased erosion of protected fastland. Groins trap little of the potential littoral drift (computed to be about 104 cubic meters per meter of shoreline per year). The sand supply in the remaining beaches is nearly equivalent to the annual loss of sediment from the entire shoreline system due to the long-term rate of erosion of the shoreline and nearshore between 1846 and 1932. ?? 1981 Springer-Verlag New York Inc.

  4. The Medieval Climate Anomaly and Little Ice Age in Chesapeake Bay and the North Atlantic Ocean

    Science.gov (United States)

    Cronin, T. M.; Hayo, K.; Thunell, R.C.; Dwyer, G.S.; Saenger, C.; Willard, D.A.

    2010-01-01

    A new 2400-year paleoclimate reconstruction from Chesapeake Bay (CB) (eastern US) was compared to other paleoclimate records in the North Atlantic region to evaluate climate variability during the Medieval Climate Anomaly (MCA) and Little Ice Age (LIA). Using Mg/Ca ratios from ostracodes and oxygen isotopes from benthic foraminifera as proxies for temperature and precipitation-driven estuarine hydrography, results show that warmest temperatures in CB reached 16-17. ??C between 600 and 950. CE (Common Era), centuries before the classic European Medieval Warm Period (950-1100. CE) and peak warming in the Nordic Seas (1000-1400. CE). A series of centennial warm/cool cycles began about 1000. CE with temperature minima of ~. 8 to 9. ??C about 1150, 1350, and 1650-1800. CE, and intervening warm periods (14-15. ??C) centered at 1200, 1400, 1500 and 1600. CE. Precipitation variability in the eastern US included multiple dry intervals from 600 to 1200. CE, which contrasts with wet medieval conditions in the Caribbean. The eastern US experienced a wet LIA between 1650 and 1800. CE when the Caribbean was relatively dry. Comparison of the CB record with other records shows that the MCA and LIA were characterized by regionally asynchronous warming and complex spatial patterns of precipitation, possibly related to ocean-atmosphere processes. ?? 2010.

  5. Terrestrially derived dissolved organic matter in the chesapeake bay and the middle atlantic bight

    Science.gov (United States)

    Mitra, Siddhartha; Bianchi, Thomas S.; Guo, Laodong; Santschi, Peter H.

    2000-10-01

    Concentrations of lignin-phenols were analyzed in high molecular weight dissolved organic matter (0.2 μm > HMW DOM > 1 kDa) isolated from surface waters of the Chesapeake Bay (C. Bay), and surface and bottom waters of the Middle Atlantic Bight (MAB). The abundance of lignin-phenols in HMW DOM was higher in the C. Bay (0.128 ± 0.06 μg L -1) compared to MAB surface waters (0.016 ± 0.004 μg L -1) and MAB bottom waters (0.005 ± 0.003 μg L -1). On an organic carbon-normalized basis, lignin-phenol abundances in the HMW DOM (i.e., Λ 6), were significantly higher ( p vanillin (Ad/Al) V in HMW DOM, indicative of lignin decay, ranged from 0.611 to 1.37 in C. Bay, 0.534 to 2.62 in MAB surface waters, and 0.435 to 1.96 in MAB bottom water. Ratios of S/V and (Ad/Al) V showed no significant differences between each environment, providing no evidence of any compositionally distinct input of terrestrial organic matter into each environment. When considering depth profiles of suspended particulate matter in the MAB, with C:N ratios, and bulk radiocarbon ages and stable carbon isotopic values in HMW DOM isolated from these areas, two scenarios present themselves regarding the sources and transport of terrestrially derived HMW DOM in the MAB. Scenario #1 assumes that a low amount of refractory terrestrial organic matter and old DOC are uniformly distributed in the oceans, both in surface and bottom waters, and that primary production in surface waters increases DOC with low lignin and younger DOC which degrades easily. In this case, many of the trends in age and biomarker composition likely reflect general patterns of Atlantic Ocean surface and bottom water circulation in the area of the MAB. Scenario 2 assumes terrestrial organic matter in bottom waters of the MAB may have originated from weathered shelf and slope sediments in nearshore areas via a combination of mechanisms (e.g., diffusion, recent resuspension events, and/or desorption of DOM from riverine POM buried deep

  6. A radiotracer study of cerium and manganese uptake onto suspended particles in Chesapeake Bay

    International Nuclear Information System (INIS)

    The oxidation kinetics of Ce(III) and Mn(II) were studied in Chesapeake Bay in March and July 1990 to establish the role of water column redox processes in contributing to Ce anomalies observed in this estuary (SHOLKOVITZ and ELDERFIELD, 1988; SHOLKOVITZ et al., 1992). Oxidation was measured by adding Mn(II) and Ce(III) to freshly collected water samples as radiotracers and measuring their uptake onto the ambient suspended particle assemblage. Mn(II) oxidation was measured by following the uptake of 54Mn(II) onto suspended particles and utilizing protocols established by other workers to distinguish oxidation from Mn(II) adsorption. The same protocols were applicable to Ce(III), using 139Ce(III), and were supported by the use of 152Eu(III) as a nonredox reactive control. Specific rates of Ce(III) and MN(II) oxidation measured at a station in the North Bay (depth = 4 m) in July were 2016% per day and 4032% per day, respectively. In March, at the same station, the specific rate of Mn(II) of oxidation was only 1-% per day, and Ce(III) oxidation was undetectable. Both Ce(III) and Mn(II) oxidation processes were inhibited by azide, indicating that they were microbially mediated. The seasonal differences probably reflect strong seasonal variation in the abundance of Mn oxidizing bacteria. No Ce(III) oxidation occured in samples collected below the oxic/anoxic interface in July. The specific rates of oxidation for both elements were over 1000 times higher than those measured in the Sargasso Sea. However, the specific rates for Ce(III) and Mn(II) were very similar to each other. This fact, coupled with similar spatial and temporal trends for specific oxidation rates, suggests a common mechanism of oxidation of both elements which may be significant in a wide range of marine environments

  7. Evaluating changes in water quality with respect to nonpoint source nutrient management strategies in the Chesapeake Bay Watershed

    Science.gov (United States)

    Keisman, J.; Sekellick, A.; Blomquist, J.; Devereux, O. H.; Hively, W. D.; Johnston, M.; Moyer, D.; Sweeney, J.

    2014-12-01

    Chesapeake Bay is a eutrophic ecosystem with periodic hypoxia and anoxia, algal blooms, diminished submerged aquatic vegetation, and degraded stocks of marine life. Knowledge of the effectiveness of actions taken across the watershed to reduce nitrogen (N) and phosphorus (P) loads to the bay (i.e. "best management practices" or BMPs) is essential to its restoration. While nutrient inputs from point sources (e.g. wastewater treatment plants and other industrial and municipal operations) are tracked, inputs from nonpoint sources, including atmospheric deposition, farms, lawns, septic systems, and stormwater, are difficult to measure. Estimating reductions in nonpoint source inputs attributable to BMPs requires compilation and comparison of data on water quality, climate, land use, point source discharges, and BMP implementation. To explore the relation of changes in nonpoint source inputs and BMP implementation to changes in water quality, a subset of small watersheds (those containing at least 10 years of water quality monitoring data) within the Chesapeake Watershed were selected for study. For these watersheds, data were compiled on geomorphology, demographics, land use, point source discharges, atmospheric deposition, and agricultural practices such as livestock populations, crop acres, and manure and fertilizer application. In addition, data on BMP implementation for 1985-2012 were provided by the Environmental Protection Agency Chesapeake Bay Program Office (CBPO) and the U.S. Department of Agriculture. A spatially referenced nonlinear regression model (SPARROW) provided estimates attributing N and P loads associated with receiving waters to different nutrient sources. A recently developed multiple regression technique ("Weighted Regressions on Time, Discharge and Season" or WRTDS) provided an enhanced understanding of long-term trends in N and P loads and concentrations. A suite of deterministic models developed by the CBPO was used to estimate expected

  8. San Francisco and Bay Area, CA, USA

    Science.gov (United States)

    1991-01-01

    Although clouds obscure part of the city of San Francisco and the mouth of the Bay (37.5N, 122.0W), many cultural and natural features in the immediate vicinity are obvious. The Bay Bridge which was damaged in the 1989 earthquake, Candlestick Park, San Mateo and Dumbarton Bridges as well as the various colored settling ponds rimming the south end of the Bay, the San Andreas and Calaveras faults and many of the major highways can be seen.

  9. Long-Term Changes in Sediment and Nutrient Delivery from Conowingo Dam to Chesapeake Bay: Effects of Reservoir Sedimentation.

    Science.gov (United States)

    Zhang, Qian; Hirsch, Robert M; Ball, William P

    2016-02-16

    Reduction of suspended sediment (SS), total phosphorus (TP), and total nitrogen is an important focus for Chesapeake Bay watershed management. The Susquehanna River, the bay's largest tributary, has drawn attention because SS loads from behind Conowingo Dam (near the river's mouth) have been rising dramatically. To better understand these changes, we evaluated histories of concentration and loading (1986-2013) using data from sites above and below Conowingo Reservoir. First, observed concentration-discharge relationships show that SS and TP concentrations at the reservoir inlet have declined under most discharges in recent decades, but without corresponding declines at the outlet, implying recently diminished reservoir trapping. Second, best estimates of mass balance suggest decreasing net deposition of SS and TP in recent decades over a wide range of discharges, with cumulative mass generally dominated by the 75∼99.5th percentile of daily Conowingo discharges. Finally, stationary models that better accommodate effects of riverflow variability also support the conclusion of diminished trapping of SS and TP under a range of discharges that includes those well below the literature-reported scour threshold. Overall, these findings suggest that decreased net deposition of SS and TP has occurred at subscour levels of discharge, which has significant implications for the Chesapeake Bay ecosystem. PMID:26744776

  10. An Approach to Understanding Complex Socio-Economic Impacts and Responses to Climate Disruption in the Chesapeake Bay Region

    Science.gov (United States)

    Schaefer, R. K.; Nix, M.; Ihde, A. G.; Paxton, L. J.; Weiss, M.; Simpkins, S.; Fountain, G. H.; APl GAIA Team

    2011-12-01

    In this paper we describe the application of a proven methodology for modeling the complex social and economic interactions of a system under stress to the regional issues that are tied to global climate disruption. Under the auspices of the GAIA project (http://gaia.jhuapl.edu), we have investigated simulating the complex interplay between climate, politics, society, industry, and the environment in the Chesapeake Bay Watershed and associated geographic areas of Maryland, Virginia, and Pennsylvania. This Chesapeake Bay simulation draws on interrelated geophysical and climate models to support decision-making analysis about the Bay. In addition to physical models, however, human activity is also incorporated via input and output calculations. For example, policy implications are modeled in relation to business activities surrounding fishing, farming, industry and manufacturing, land development, and tourism. This approach fosters collaboration among subject matter experts to advance a more complete understanding of the regional impacts of climate change. Simulated interactive competition, in which teams of experts are assigned conflicting objectives in a controlled environment, allow for subject exploration which avoids trivial solutions that neglect the possible responses of affected parties. Results include improved planning, the anticipation of areas of conflict or high risk, and the increased likelihood of developing mutually acceptable solutions.

  11. Processing of single channel air and water gun data for imaging an impact structure at the Chesapeake Bay

    Science.gov (United States)

    Lee, Myung W.

    1999-01-01

    Processing of 20 seismic profiles acquired in the Chesapeake Bay area aided in analysis of the details of an impact structure and allowed more accurate mapping of the depression caused by a bolide impact. Particular emphasis was placed on enhancement of seismic reflections from the basement. Application of wavelet deconvolution after a second zero-crossing predictive deconvolution improved the resolution of shallow reflections, and application of a match filter enhanced the basement reflections. The use of deconvolution and match filtering with a two-dimensional signal enhancement technique (F-X filtering) significantly improved the interpretability of seismic sections.

  12. Estimating consumption rates of juvenile sandbar sharks (Carcharhinus plumbeus) in Chesapeake Bay, Virginia, using a bioenergetics model*

    OpenAIRE

    Dowd, W. Wesley; Brill, Richard W; Bushnell, Peter G.; Musick, John A.

    2006-01-01

    Using a bioenergetics model, we estimated daily ration and seasonal prey consumption rates for six age classes of juvenile sandbar sharks (Carcharhinus plumbeus) in the lower Chesapeake Bay summer nursery area. The model, incorporating habitat and species-specific data on growth rates, metabolic rate, diet composition, water temperature (range 16.8-27.9 degrees C), and population structure, predicted mean daily rations between 2.17 +/- 0.03 (age-0) and 1.30 +/- 0.02 (age-5) % body mass/day. T...

  13. Flock sizes and sex ratios of canvasbacks in Chesapeake Bay and North Carolina

    Science.gov (United States)

    Haramis, G.M.; Derleth, E.L.; Link, W.A.

    1994-01-01

    Knowledge of the distribution, size, and sex ratios of flocks of wintering canvasbacks (Aythya valisineria) is fundamental to understanding the species' winter ecology and providing guidelines for management. Consequently, in winter 1986-87, we conducted 4 monthly aerial photographic surveys to investigate temporal changes in distribution, size, and sex ratios of canvasback flocks in traditional wintering areas of Chesapeake Bay and coastal North Carolina. Surveys yielded 35mm imagery of 194,664 canvasbacks in 842 flocks. Models revealed monthly patterns of flock size in North Carolina and Virginia, but no pattern of change in Maryland. A stepwise analysis of flock size and sex ratio fit a common positive slope (increasing proportion male) for all state-month datasets, except for North Carolina in February where the slope was larger (P lt 0.001). State and month effects on intercepts were significant (P lt 0.001) and confirmed a previously identified latitudinal gradient in sex ratio in the survey region. There was no relationship between flock purity (% canvasbacks vs. other species) and flock size except in North Carolina in January, February, and March when flock purity was related to flock size. Contrasting characteristics in North Carolina with regard to flock size (larger flocks) and flock purity suggested that proximate factors were reinforcing flocking behavior and possibly species fidelity there. Of possible factors, the need to locate foraging sites within this large, open-water environment was hypothesized to be of primary importance. Comparison of January 1981 and 1987 sex ratios indicated no change in Maryland, but lower (P lt 0.05) canvasback sex ratios (proportion male) in Virginia and North Carolina.

  14. Control of upland bank erosion through tidal marsh construction on restored shores: Application in the maryland portion of Chesapeake Bay

    Science.gov (United States)

    Garbisch, Edgar W.; Garbisch, Joanna L.

    1994-09-01

    During the period of 1972 through 1993, Environmental Concern Inc. (EC) and its recent (1989) affiliate Environmental Construction Company (ECC) have completed 216 marsh construction projects to control upland bank erosion in tributaries of the Maryland portion of Chesapeake Bay. Of these projects, 26 have involved marsh construction on unaltered existing shores and 190 have utilized marsh construction on shores that have been restored to former increased elevations through shoreline filling and grading. This paper describes the latter restoration technique. Throughout the 21-year period of applying the technique for long-term upland bank erosion control, refinements to the design standards and criteria for site suitability have been made so as to optimize its successful application. As a result of this experience, a reliable bioengineering restoration technique has evolved to control upland bank erosion. This paper describes the details of this successful technique through a review of: (1) its objectives and benefits, (2) suitability of sites for its application, (3) the design of its shore restoration, (4) its construction, (5) its maintenance, and (6) comparison of its cost with those of structural techniques for bank erosion control. Although the technique has only been applied in the Maryland portions of Chesapeake Bay, its applicability should, with modifications, be broadly applicable to all water bodies.

  15. Transitions in nirS-type Denitrifier Diversity, Community Composition, and Biogeochemical Activity along the Chesapeake Bay Estuary

    Directory of Open Access Journals (Sweden)

    ChristopherAFrancis

    2013-08-01

    Full Text Available Chesapeake Bay, the largest estuary in North America, can be characterized as having steep and opposing gradients in salinity and dissolved inorganic nitrogen along the main axis of the Bay. In this study, the diversity of nirS gene fragments (encoding cytochrome cd1-type nitrite reductase, physical/chemical parameters, and benthic N2-fluxes were analyzed in order to determine how denitrifier communities and biogeochemical activity vary along the estuary salinity gradient. The nirS gene fragments were PCR-amplified, cloned, and sequenced from sediment cores collected at five stations. Sequence analysis of 96 to 123 nirS clones from each station revealed extensive overall diversity in this estuary, as well as distinct spatial structure in the nirS sequence distributions. Both nirS-based richness and community composition varied among stations, with the most dramatic shifts occurring between low-salinity (oligohaline and moderate-salinity (mesohaline sites. For four samples collected in April, the nirS-based richness, nitrate concentrations, and N2-fluxes all decreased in parallel along the salinity gradient from the oligohaline northernmost station to the highest salinity (polyhaline station near the mouth of the Bay. The vast majority of the 550 nirS sequences were distinct from cultivated denitrifiers, although many were closely related to environmental clones from other coastal and estuarine systems. Interestingly, 8 of the 172 OTUs identified accounted for 42% of the total nirS clones, implying the presence of a few dominant and many rare genotypes, which were distributed in a non-random manner along the salinity gradient of Chesapeake Bay. These data, comprising the largest dataset to investigate nirS clone sequence diversity from an estuarine environment, also provided information that was required for the development of nirS microarrays to investigate the interaction of microbial diversity, environmental gradients, and biogeochemical

  16. Effects of energy related activities on the plankton of the Chesapeake Bay. Section I. Work in progress. Progress report, 1 August 1975--31 July 1976

    International Nuclear Information System (INIS)

    Progress is reported on the following research projects: release of dissolved organic carbon by phytoplankton; plankton respiration and nutrient regeneration; bacterial utilization of labeled compounds; effects of heat and chlorine on natural assemblages of Chesapeake Bay phytoplankton; and nutrient flux between sediment and water

  17. Geochemical characteristics of basement target rocks, suevitic glasses from the Eyreville B drill core, Chesapeake Bay impact structure, and three bediasites

    Czech Academy of Sciences Publication Activity Database

    Skála, Roman; Langenhorst, F.; Deutsch, A.

    Boulder: Geological Society of America, 2009, s. 435-445. (Special papers of the Geological Society of America). ISBN 978-0-8137-2458-4 Institutional research plan: CEZ:AV0Z30130516 Keywords : Chesapeake Bay impact crater * Eyreville B core hole * impact glasses * bediasites * tektites * geochemistry Subject RIV: DD - Geochemistry

  18. DIFFUSIVE EXCHANGE OF GASEOUS POLYCYCLIC AROMATIC HYDROCARBONS AND POLYCHLORINATED BIPHENYLS ACROSS THE AIR-WATER INTERFACE OF THE CHESAPEAKE BAY. (R825245)

    Science.gov (United States)

    Dissolved and gas-phase concentrations of nine polycyclic aromatic hydrocarbons and 46 polychlorinated biphenyl congeners were measured at eight sites on the Chesapeake Bay at four different times of the year to estimate net diffusive air-water gas exchange rates. Gaseous PAHs ar...

  19. Effects of energy related activities on the plankton of the Chesapeake Bay. Section I. Work in progress. Progress report, 1 August 1975--31 July 1976

    Energy Technology Data Exchange (ETDEWEB)

    Taft, J.L.

    1976-04-01

    Progress is reported on the following research projects: release of dissolved organic carbon by phytoplankton; plankton respiration and nutrient regeneration; bacterial utilization of labeled compounds; effects of heat and chlorine on natural assemblages of Chesapeake Bay phytoplankton; and nutrient flux between sediment and water. (HLW)

  20. Microplastic contamination in the San Francisco Bay, California, USA.

    Science.gov (United States)

    Sutton, Rebecca; Mason, Sherri A; Stanek, Shavonne K; Willis-Norton, Ellen; Wren, Ian F; Box, Carolynn

    2016-08-15

    Despite widespread detection of microplastic pollution in marine environments, data describing microplastic abundance in urban estuaries and microplastic discharge via treated municipal wastewater are limited. This study presents information on abundance, distribution, and composition of microplastic at nine sites in San Francisco Bay, California, USA. Also presented are characterizations of microplastic in final effluent from eight wastewater treatment plants, employing varying treatment technologies, that discharge to the Bay. With an average microplastic abundance of 700,000particles/km(2), Bay surface water appears to have higher microplastic levels than other urban waterbodies sampled in North America. Moreover, treated wastewater from facilities that discharge into the Bay contains considerable microplastic contamination. Facilities employing tertiary filtration did not show lower levels of contamination than those using secondary treatment. As textile-derived fibers were more abundant in wastewater, higher levels of fragments in surface water suggest additional pathways of microplastic pollution, such as stormwater runoff. PMID:27289280

  1. Spatial-temporal variability in diazotroph assemblages in Chesapeake Bay using an oligonucleotide nifH microarray.

    Science.gov (United States)

    Moisander, Pia H; Morrison, Amanda E; Ward, Bess B; Jenkins, Bethany D; Zehr, Jonathan P

    2007-07-01

    The distribution of nitrogen-fixing microorganisms in the Chesapeake Bay was investigated using fingerprints from a nifH microarray comprised of 706 60-mer oligonucleotide nifH probes representing cultivated organisms and environmental clones from different nifH clusters. Diverse nifH targets, amplified from samples using degenerate nifH primers, were detected in water column and sediment samples collected in April and October, 2001-2002. Total nifH richness and diversity (Simpson's and Shannon indices) were highest at the most riverine, oligohaline North Bay station. In most samples, the highest diversity was in nifH Cluster 3, which includes many anaerobes, while Cluster 1 (alpha-, beta- gamma- Proteobacteria, Cyanobacteria) targets had the greatest microarray signal intensities. In a multidimensional scaling analysis, deep water communities from April and October were similar within each of the sampling sites, while the surface communities had more variability. Diazotroph communities in the water column in the North Bay were distinct from the Mid- and South Bay communities, and there was a gradual change in sediment diazotroph assemblages from the North to the South Bay. Diazotrophic assemblages from the majority of the water column samples from the Mid- and South Bay clustered with the sediment assemblage in Mid-Bay. Dissolved inorganic nitrogen, salinity, dissolved organic carbon and dissolved organic phosphorus had a significant relationship with the diazotrophic bacterioplankton community. Higher diversity in the freshwater end of the system may reflect variability in disturbance rates and environmental conditions such as forms and concentrations of organic matter, nutrients and oxygen. PMID:17564615

  2. RESGPSPNTS_JD249.SHP: Navigation and Bathymetry Points of Ship Position During Continuous Resistivity Profile Data Collection in the Potomac River/Chesapeake Bay on Sept. 6, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  3. RESGPSLNS_JD249.SHP: Ship Trackline along which Continuous Resistivity Profile Data was Collected in the Potomac River/Chesapeake Bay on Sept., 6, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  4. SHIP NAVIGATION: ANSI Text File of the Navigation and Bathymetry Recorded by the Ship's Differential Global Positioning System (DGPS) in the Potomac River/Chesapeake Bay from Sept. 6 to Sept. 8, 2006 - USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  5. RESGPSLNS_JD250.SHP: Ship Trackline Along Which Continuous Resistivity Profile (CRP) Data was Collected in the Potomac River/Chesapeake Bay on Sept. 7, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  6. RESGPSPNTS_JD250.SHP: Navigation, Bathymetry and Temperature Points at the Ship Position During Continuous Resistivity Profile Data Collection in the Potomac River/Chesapeake Bay on Sept. 7, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  7. MRG2006_ALLZYZ.SHP: Processed Continuous Resistivity Profile (CRP) Data Below the Sediment Water Interface From the Potomac River/Chesapeake Bay collected from Sept. 6, 2006 to Sept. 8, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  8. RESGPSPNTS_JD251.SHP: Navigation, Bathymetry and Temperature Point at the Ship Position During Continuous Resistivity Profile Data Collection in the Potomac River/Chesapeake Bay on Sept. 8, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  9. SHOT500SORT_GEOG.SHP: Point Shapefile of 500 Shot Interval Point Navigation For Seismic Data Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  10. SHOT100SORT_GEOG.SHP: Point Shapefile of 100 Shot Interval Point Navigation For Seismic Data Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  11. TRACK_ROUTE_CALIB_GEOG.SHP: Shot Point Calibrated Trackline Navigation for Seismic Data Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  12. ALLSHOTS_GEOG.SHP: Point Shapefile of All the Unique Seismic Shot Point Navigation Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  13. Seismic-Reflection Profile Data in JPEG Image Format Collected in the Potomac River/Chesapeake Bay from Sept. 6, 2006 to Sept. 8, 2006 on USGS Cruise 06018

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — In order to test hypotheses about groundwater flow under and into Chesapeake Bay, geophysical surveys were conducted by U.S. Geological Survey (USGS) scientists on...

  14. Cape Cod, Buzzard's Bay, Massachusetts, USA

    Science.gov (United States)

    1990-01-01

    Cape Cod, Massachusetts, USA (42.0N, 70.0W) is a national seashore recreation area with many fine resorts and summer estate homes. Geologically, the cape is a deposit of earth and stone called a terminal moraine, left by the great Pleistocene glaciers of about 20,000 years ago. The through canal at the base of the cape is a manmade feature for waterborne traffic and is part of the Intercoastal Canal network. The cape actually begins south of the canal.

  15. Radar monitoring of wetland hydrology: Water quality implications for the Chesapeake Bay

    Science.gov (United States)

    Wetlands are hydrologically dynamic ecosystems which have the potential to improve water quality. Unfortunately, many of the Chesapeake Bay’s wetlands, especially forested wetlands, have been lost or degraded due to human impacts primarily associated with agriculture and urban/suburban development. ...

  16. Exploiting the Free Landsat Archive for Operational Monitoring of Ecosystem Condition and Change Across the Chesapeake Bay Watershed

    Science.gov (United States)

    BrowndeColstoun, Eric

    2010-01-01

    For the first time, all imagery acquired by the Landsat series of satellites is being made available by the USGS to users at no cost. This represents a key opportunity to use Landsat in a truly operational monitoring framework: large regions of the U.S. such as the Chesapeake Bay Watershed can now be analyzed using "wall-to-wall" imagery at timescales from approximately 1 month to several years. With the future launch of the Landsat Data Continuity Mission (LDCM) and Decadal Survey missions such as the hyperspectral HyspIRI, it is imperative to develop robust processing systems to perform annual ecosystem assessments over large regions such as the Chesapeake Bay. We have been working at NASA's Goddard Space Flight Center (GSFC) to develop an integrative framework for inserting 30m, annual, Landsat based data and derived products into the existing decision support system for the Bay, with a particular focus on ecosystem condition and changes over the entire watershed. The basic goal is to use a 'stack' of Landsat imagery with 40% or less cloud cover to produce multi-date (2005-2009 period), cloud/shadow/gap-free composited surface reflectance products that will support the creation of watershed scale land cover/ use products and the monitoring of ecosystem change across the Bay. Our scientific focus extends beyond the conventional definition of land cover (i.e. a classification of vegetation type) as we propose to monitor both changes in surface type (e.g. forest to urban), vegetation structure (e.g. forest disturbance due to logging or insect damage), as well as winter crop cover. These processes represent a continuum from large, interannual changes in land cover type, to subtler, intra-annual changes associated with short-term disturbance. The free Landsat data are being processed to surface reflectance and composited using the existing Landsat Ecosystem Disturbance Adaptive Processing System here at NASA/ GSFC, and land cover products (type, tree cover

  17. The Chesapeake Bay Impact Crater: An Educational Investigation for Students into the Planetary Impact Process and its Environmental Consequences

    Science.gov (United States)

    Levine, Arlene S.

    2008-01-01

    Planetary impact craters are a common surface feature of many planetary bodies, including the Earth, the Moon, Mars, Mercury, Venus, and Jupiter s moons, Ganymede and Callisto. The NASA Langley Research Center in Hampton, VA, is located about 5 km inside the outer rim of the Chesapeake Bay Impact Crater. The Chesapeake Bay Impact Crater, with a diameter of 85 km is the sixth largest impact crater on our planet. The U.S. Geological Survey (USGS), in collaboration with the NASA Langley Research Center, the Virginia Department of Environmental Quality (VDEQ), the Hampton Roads Planning District Commission (HRPDC), and the Department of Geology of the College of William and Mary (WM) drilled into and through the crater at the NASA Langley Research Center and obtained a continuous core to a depth of 2075.9 ft (632.73 meters) from the Chesapeake Bay Impact Crater. At the NASA Langley location, the granite basement depth was at 2046 ft (623.87 meters). This collaborative drilling activity provided a unique educational opportunity and ongoing educational partnership between USGS, NASA Langley and the other collaborators. NASA Langley has a decade-long, ongoing educational partnership with the Colonial Coast Council of the Girl Scouts. The core drilling and on site analysis and cataloguing of the core segments provided a unique opportunity for the Girl Scouts to learn how geologists work in the field, their tools for scientific investigation and evaluation, how they perform geological analyses of the cores in an on-site tent and learn about the formation of impact craters and the impact of impacting bodies on the sub-surface, the surface, the oceans and atmosphere of the target body. This was accomplished with a two-part activity. Girl Scout day camps and local Girl Scout troops were invited to Langley Research Center Conference Center, where more than 300 Girl Scouts, their leaders and adult personnel were given briefings by scientists and educators from the USGS, NASA

  18. Uptake of Trace Elements in Aragonitic Otoliths of an Estuarine Dependent Fish, Spotted Seatrout, from surface waters of Chesapeake Bay.

    Science.gov (United States)

    Dorval, E.; Jones, C.; Hannigan, R.; Sako, A.

    2002-05-01

    Seagrass beds in Chesapeake Bay are critical habitats for early life stages of Spotted seatrout, {\\Cynoscion nebulosus}. Spotted seatrout spawn in surface waters in the Bay during late spring and thereafter their larvae settle in seagrass beds where the juveniles spend three to four months. These habitats provide refuge and food for larvae and juveniles, influencing growth, mortality, and survival rates. Identification of essential seagrass habitats for estuarine-dependent fish is of primary importance given the current decline in habitat quality. We hypothesized that the geochemistry of surface waters in Chesapeake Bay is different along both the latitudinal and longitudinal gradients, and that we could use trace elements in otoliths as a natural tag to differentiate survivors among seagrass beds. We investigated the relationship between water and otolith trace element chemistry and we present here some preliminary results. From July to September 2001 we collected surface waters during spring tide from seagrass beds and around the mouth of the Potomac, Rappahannock, and York river. Waters were filtered through a 0.45 uM filter and acidified to pH < 2 with ultrapure nitric acid. In September, we collected juvenile fish in seagrass beds along the Western and Eastern shores, Tangier and Smith Islands. From each individual fish one sagittal otolith was extracted, cleaned with milli-Q water, soaked for 5 minutes in ultrapure hydrogen peroxide, rinsed, and sonicated. All dried and cleaned otoliths were dissolved in ultrapure nitric acid. We used trace metal clean procedures to process both water and otoliths and trace elements were measured by sector field ICP-MS. Both waters and otoliths showed distinct chemical signatures among seagrass beds, and samples could be classified with high accuracy to their respective sites of collection. For most seagrass beds Ba/Ca, Rb/Ca, V/Ca showed inverse relationship between water and otolith whereas Sr/Ca was positively correlated

  19. The use of aircraft and satellite remote sensing of phytoplankton chlorophyll concentrations in case 2 estuarine waters of the Chesapeake Bay

    Science.gov (United States)

    Harding, Lawrence W., Jr.

    1989-01-01

    Two projects using remote sensing of phytoplankton chlorophyll concentrations in the Chesapeake Bay estuary were proposed. The first project used aircraft remote sensing with a compact radiometer system developed at NASA's Goddard Space Flight Center (GSFC), the Ocean Data Acquisition System (ODAS). ODAS includes three radiometers at 460, 490, and 520 nm, an infrared temperature sensor (PRT-5), Loran-C for navigation, and a data acquisition system using a PC and mass storage device. This instrument package can be flown in light aircraft at relatively low expense, permitting regular and frequent flights. Sixteen flights with ODAS were completed using the Virginia Institute of Marine Science's De Havilland 'Beaver'. The goal was to increase spatial and temporal resolution in assaying phytoplankton pigment concentrations in the Chesapeake. At present, analysis is underway of flight data collected between March and July 1989. The second project focused on satellite data gathered with the Nimbus-7 Coastal Zone Color Scanner (CZSC) between late 1978 and mid 1986. The problem in using CZSC data for the Chesapeake Bay is that the optical characteristics of this (and many) coastal and estuarine waters are distinct from those of the open ocean for which algorithms for computing pigment concentrations were developed. The successful use of CZCS data for the estuary requires development of site-specific algorithms and analytical approaches. Of principal importance in developing site-specific procedures is the availability of in-situ data on pigment concentrations. A significant data set was acquired from EPA's Chesapeake Bay Program in Annapolis, Maryland, and clear satellite scenes are being analyzed for which same-day sea truth measurements of pigment were obtained. Both the University of Miami and GSFC Seapak systems are being used in this effort. The main finding to date is an expected one, i.e., the algorithms developed for oceanic waters are inadequate to compute pigment

  20. Total nutrient and sediment loads, trends, yields, and nontidal water-quality indicators for selected nontidal stations, Chesapeake Bay Watershed, 1985–2011

    Science.gov (United States)

    Langland, Michael J.; Blomquist, Joel D.; Moyer, Douglas; Hyer, Kenneth; Chanat, Jeffrey G.

    2013-01-01

    The U.S. Geological Survey, in cooperation with Chesapeake Bay Program (CBP) partners, routinely reports long-term concentration trends and monthly and annual constituent loads for stream water-quality monitoring stations across the Chesapeake Bay watershed. This report documents flow-adjusted trends in sediment and total nitrogen and phosphorus concentrations for 31 stations in the years 1985–2011 and for 32 stations in the years 2002–2011. Sediment and total nitrogen and phosphorus yields for 65 stations are presented for the years 2006–2011. A combined nontidal water-quality indicator (based on both trends and yields) indicates there are more stations classified as “improving water-quality trend and a low yield” than “degrading water-quality trend and a high yield” for total nitrogen. The same type of 2-way classification for total phosphorus and sediment results in equal numbers of stations in each indicator class.

  1. Water-quality assessment of DOD installations/facilities in the Chesapeake Bay Region. Phase 3. Volume 2. Overall approach, findings and recommendations. Technical report, 1985-1987

    Energy Technology Data Exchange (ETDEWEB)

    1987-11-01

    This report represents the culmination of a two-year, three-phase effort to determine the relative impact of DOD activities on the water quality and living resources of the Chesapeake Bay. Phase I defined the recent historical and present pollution potential of all 66 DOD installations in the Bay's drainage basin, and developed a preliminary screening procedure to categorize these installations according to existing or potential impacts on the Bay and its tributaries. Phase II developed and tested a detailed assessment methodology on six installations to define the character and extent of their impact on the Bay. Phase III applied this tested methodology to the remaining 31 installations identified in Phase I as needing more detailed assessment, and summarizes impacts and program recommendations from an installation, regional, and Bay-wide perspective. This volume presents detailed results of this analysis.

  2. A population dynamic model assessing options for managing eastern oysters (Crassostrea virginica) and triploid Suminoe oysters (Crassostrea ariakensis) in Chesapeake Bay

    OpenAIRE

    Dew, Jodi Rebecca

    2002-01-01

    A demographic population simulation model was developed to examine alternative fishery management strategies and their likely effects on the probability of extirpation of local eastern oyster (Crassostrea virginica) populations in the Chesapeake Bay. Management strategies include varying the minimum shell length-at-harvest, harvest rate, and rate and frequency of stocking of oyster seed with respect to varying salinities and oyster population densities. We also examined the rate of disease-me...

  3. Trends in Surface-Water Nitrate-N Concentrations and Loads from Predominantly-Forested Watersheds of the Chesapeake Bay Basin

    Science.gov (United States)

    Eshleman, K. N.

    2011-12-01

    Water quality monitoring data from streams and rivers provide the "gold standard" by which progress toward achieving real reductions in nutrient loadings to Chesapeake Bay must ultimately be assessed. The most recent trend results posted at the Chesapeake Bay Program (CBP) website reveal that a substantial percentage of tributaries are now showing long-term declines in flow-adjusted concentrations of nutrients and sediments: 22 sites showed statistically significant (p wastewater treatment plants and practices to reduce nutrients on farms and suburban lands, have reduced concentrations of nitrogen." But could this conclusion be pre-mature? I recently undertook a comparable analysis of long-term nitrate-N trends for a different group of watersheds (all located in the Chesapeake Bay watershed with long data records); this group includes nine watersheds that are predominantly (i.e., >75%) forested, plus five other Potomac River subwatersheds added for comparison. Based on comparable data and analytical methods to those used by CBP partners and USGS, 13 of the 14 sites-including both Potomac River stations (Chain Bridge at Washington DC and Hancock, Maryland)-showed statistically significant decreasing linear trends in annual flow-weighted nitrate-N concentration. Only one station-the heavily agricultural Upper Monocacy River-did not show a statistically significant (p < 0.05) trend. Five of the predominantly-forested watersheds also showed statistically significant decreasing trends in annual nitrate-N loads, and none of the stations showed a trend in annual runoff presumably due to high inter-annual hydroclimatological variability. While the largest absolute changes in nitrate-N concentration corresponded to the least forested watersheds, the largest percentage changes in nitrate-N concentration were actually observed for those watersheds with the greatest percentages of forestland. This result suggests that the natural dynamics of forests may be playing a very

  4. Evaluating local and regional scales of environmental change from sediment characteristics of a tributary of the upper Chesapeake Bay: a geospatial approach to understanding the role of humans on elemental transport and fate

    Science.gov (United States)

    Krahforst, C.; Hartman, S.; Eisen-Cuadra, A.; Bruce, S.; Sherman, L.; Kehm, K.

    2013-12-01

    Most of our coastal systems have experienced changes in ecosystem quality due to increased anthropogenic activities, often resulting in the degradation of water and habitat quality. Estuaries are often the first of marine systems that experience these changes. The distribution of trace elements (V, Cr, Cu, Ni, Pb, As, Sn, Ag, Zn, and Cd) and other sediment characteristics in surface sediments and sediment cores from the Chester River - an estuary located in a predominantly agricultural watershed of the upper Chesapeake Bay, USA - is being determined in order to add to the understanding of contaminant transport and fate and evaluate the likelihood for success of strategies designed to meet or improve the ecological condition of estuaries. The high amount of suspended sediment in the Chester River (10-20 mg L-1) is an important factor controlling water quality conditions and a prime focus for environmental management. Sources of suspended mater and its elemental composition are the result of local runoff, atmospheric deposition, local resuspension, and exchange with the Chesapeake Bay. Preliminary results from multivariate analytic and geospatial mapping analyses of sediment surface grabs display significant covariance with Al for many of the elements investigated which may indicate limited exogenic sources of contamination for of sediments of this watershed. For example total Pb sediment concentrations were mostly below the NOAA's low toxic effects level (94%) and appear to be dominated by crustal weathering or from accelerated soil erosion (Pb vs. Al, r2 = 0.84). These analyses, coupled with sequential leaching of elements from these sediments, sediment organic carbon, activities of selected radionuclides of sediment cores and main stem water quality surveys provide added information of the roles of local land use and region scale processes on ecosystem condition and may direct future management for improving environmental quality of estuaries.

  5. Birth of the modern Chesapeake Bay estuary between 7.4 and 8.2 ka and implications for global seal-level rise

    Science.gov (United States)

    Bratton, J.F.; Colman, Steven M.; Thieler, E.R.; Seal, R.R.

    2003-01-01

    Two major pulses of sea-level rise are thought to have taken place since the last glacial maximum - meltwater pulses (mwp) 1A (12 cal ka) and 1B (9.5 cal ka). Between mwp 1B and about 6 cal ka, many of the complex coastal ecosystem which ring the world's oceans began to form. Here we report data for rhenium, carbon isotopes, total organic carbon, and fossil oysters from Chesapeake Bay which span the transition from fresh to brackish water conditions in the bay in the mid-Holocene. These data constrain sea-level change and resulting environmental change in the bay. They indicate that the transition was rapid, and that it was produced by (1) a third pulse of rapid eustatic sea-level rise, or (2) a geometry of the prehistoric Chesapeake Bay basin which predisposed it to a nonlinear response to a steadily rising sea level. Similar nonlinear changes in vulnerable coastal environments are likely to take place in the future due to polar warming, regardless of the timing or rate of sea-level rise.

  6. Studies of dry deposition of trace elements and diesel soot onto Lake Michigan and the Chesapeake Bay

    International Nuclear Information System (INIS)

    As part of the Atmospheric Exchange Over Lakes and Oceans Study (AEOLOS) study, the University of Maryland participated in four intensive field campaigns, three on Lake Michigan (LM) and one on the Chesapeake Bay (CB), to determine the size distributions of potentially toxic elemental aerosol constituents, determine their sources, and their dry deposition loadings to surface waters. The work further seeks to elucidate the relative importance of constituents of fine- and coarse particles, as differentiation of these modes is essential to the eventual formation of control strategies. Unique components of the UMCP studies include (1) resolution of toxic elemental components of aerosol particles depositing to LM and CB by particle size and by source and (2) a Lake-wide evaluation of the importance of fine and coarse particle deposition to inorganic contamination of LM surface waters. In addition, a unique component of the Baltimore Study was the application of a sensitive iridium tracer to intentionally tag emissions form the City of Baltimore's sanitation truck fleet to tag the Baltimore urban plume and to determine the atmospheric behavior of diesel soot particles, a major source of urban carbon aerosol and the principle carrier of toxic polynuclear aromatic hydrocarbons. The work encompasses results for >40 elements by X-ray fluorescence and instrumental neutron activation analyses of more than 700 individual size-segregated aerosol, deposition, urban dust, and surface-water-suspended particulate samples. An overview of the results of these studies will be presented

  7. The Effect of Dissolved Polyunsaturated Aldehydes on Microzooplankton Growth Rates in the Chesapeake Bay and Atlantic Coastal Waters

    Directory of Open Access Journals (Sweden)

    Peter J. Lavrentyev

    2015-05-01

    Full Text Available Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA. Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the growth rates of natural ciliate and dinoflagellate populations in the Chesapeake Bay and the coastal Atlantic waters. The overall effect of PUA on microzooplankton growth was negative, especially at the higher concentrations, but there were pronounced differences in response among common planktonic species. For example, the growth of Codonella sp., Leegaardiella sol, Prorodon sp., and Gyrodinium spirale was impaired at 2 nM, whereas Strombidium conicum, Cyclotrichium gigas, and Gymnodinium sp. were not affected even at 20 nM. These results indicate that PUA can induce changes in microzooplankton dynamics and species composition.

  8. The effect of dissolved polyunsaturated aldehydes on microzooplankton growth rates in the Chesapeake Bay and Atlantic coastal waters.

    Science.gov (United States)

    Lavrentyev, Peter J; Franzè, Gayantonia; Pierson, James J; Stoecker, Diane K

    2015-05-01

    Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA). Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the growth rates of natural ciliate and dinoflagellate populations in the Chesapeake Bay and the coastal Atlantic waters. The overall effect of PUA on microzooplankton growth was negative, especially at the higher concentrations, but there were pronounced differences in response among common planktonic species. For example, the growth of Codonella sp., Leegaardiella sol, Prorodon sp., and Gyrodinium spirale was impaired at 2 nM, whereas Strombidium conicum, Cyclotrichium gigas, and Gymnodinium sp. were not affected even at 20 nM. These results indicate that PUA can induce changes in microzooplankton dynamics and species composition. PMID:25955757

  9. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    Directory of Open Access Journals (Sweden)

    M. L. Kirwan

    2013-03-01

    Full Text Available The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  10. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    Directory of Open Access Journals (Sweden)

    M. L. Kirwan

    2012-10-01

    Full Text Available The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  11. The Efficacy of Constructed Stream-Wetland Complexes at Reducing the Flux of Suspended Solids to Chesapeake Bay.

    Science.gov (United States)

    Filoso, Solange; Smith, Sean M C; Williams, Michael R; Palmer, Margaret A

    2015-08-01

    Studies documenting the capacity of restored streams to reduce pollutant loads indicate that they are relatively ineffective when principal watershed stressors remain intact. Novel restorations are being designed to increase the hydraulic connectivity between stream channels and floodplains to enhance pollutant removal, and their popularity has increased the need for measurements of potential load reductions. Herein we summarize input-output budgets of total suspended solids (TSS) in two Coastal Plain lowland valleys modified to create stream-wetland complexes located above the head-of-tide on the western shore of Chesapeake Bay. Loads entering (input) and exiting (output) the reconfigured valleys over three years were 103 ± 26 and 85 ± 21 tons, respectively, and 41 ± 10 and 46 ± 9 tons, respectively. In both cases, changes in loads within the reconfigured valleys were insignificant relative to cumulative errors. High variability of TSS retention among stormflow events suggests that the capacity of these systems to trap and retain solids and their sustainability depend on the magnitude of TSS loads originating upstream, design characteristics, and the frequency and magnitude of large storms. Constructed stream-wetland complexes receiving relatively high TSS loads may experience progressive physical and chemical changes that limit their sustainability. PMID:26181355

  12. Estimation of annual mortality rates for eastern oysters (Crassostrea virginica) in Chesapeake Bay based on box counts and application of those rates for projection of population growth of both C. virginica and the Asian oyster (C. ariakensis)

    OpenAIRE

    Vølstad, Jon Helge; Dew, J. R.; Tarnowski, Mitchell

    2008-01-01

    In an effort to restore the ecological role of oysters in Chesapeake Bay and the economic benefits of a commercial fishery, the states of Maryland and Virginia are considering introducing the nonnative Asian oyster (Crassostrea ariakensis) into the Bay. As part of an ecological risk assessment (ERA) to evaluate the proposed action and alternatives, demographic modeling is being used to project the change in populations of both the Asian and the native eastern oyster (C. virginica) in the Bay ...

  13. The history of Chesapeake Bay's blue crab (Callinectes sapidus: fisheries and management Perspectiva histórica de la pesquería y del manejo del cangrejo azul (Callinectes sapidus: en la Bahía de Chesapeake

    Directory of Open Access Journals (Sweden)

    Cluney Stagg

    1997-01-01

    Full Text Available Major blue crab fisheries have existed on the Atlantic coast of the United States for at least 100 years, and on the Gulf of Mexico coast for more than 50 years. From 1990 to 1994, reported landings averaged more than 96 million kg per year, with a reported dockside value of more than $200 million. Until about 1950, Chesapeake Bay accounted for over 75% of the total reported U.S. harvest of blue crabs, but less than 50% over the last two decades. The United States blue crab fishery is made up of hundreds to thousands of small-scale fishermen. The commercial fishery has a hard crab component and a soft crab (recently molted fishery. There is also a substantial recreational (casual fishery for blue crabs. Since the 1950s, crab pots have accounted for the largest proportion of reported landings. Other major gears include the trotline, crab scrape and crab dredge. U.S. blue crab fisheries have undergone periods of low abundance. Changes in fishing effort and power, environmental conditions, ecological interactions and market forces have been hypothesized as causative factors. Management measures in the Chesapeake Bay blue crab fisheries have included size and life stage, season, and gear limitations, as well as entry restrictions. An historical perspective should be taken in the interpretation of the recent decline in reported harvests. A 1997 stock assessment concluded that Chesapeake Bay blue crab stocks were fully exploited but in no current danger of recruitment overfishingImportantes pesquerías de jaiba azul han existido en la costa Atlántica de los Estados Unidos por lo menos durante 100 años, y en la costa del Golfo de México por más de 50 años. Desde 1990 a 1994, los desembarques informados promedian más de 96 millones de kg por año, con un valor playa de más de US$ 200 millones. Hasta cerca de 1950, la Bahía de Chesapeake contribuía sobre el 75% del total de la captura de jaibas azules informada para EE.UU., pero menos del 50% en

  14. Nutrient and suspended-sediment trends, loads, and yields and development of an indicator of streamwater quality at nontidal sites in the Chesapeake Bay watershed, 1985-2010

    Science.gov (United States)

    Langland, Michael; Blomquist, Joel; Moyer, Douglas; Hyer, Kenneth

    2012-01-01

    The U.S. Geological Survey (USGS) updates information on loads of, and trends in, nutrients and sediment annually to help the Chesapeake Bay Program (CBP) investigators assess progress toward improving water-quality conditions in the Chesapeake Bay and its watershed. CBP scientists and managers have worked since 1983 to improve water quality in the bay. In 2010, the U.S. Environmental Protection Agency (USEPA) established a Total Maximum Daily Load (TMDL) for the Chesapeake Bay. The TMDL specifies nutrient and sediment load allocations that need to be achieved in the watershed to improve dissolved oxygen, water-clarity, and chlorophyll conditions in the bay. The USEPA, USGS, and state and local jurisdictions in the watershed operate a CBP nontidal water-quality monitoring network and associated database that are used to update load and trend information to help assess progress toward reducing nutrient and sediment inputs to the bay. Data collected from the CBP nontidal network were used to estimate loads and trends for two time periods: a long-term period (1985-2010) at 31 "primary" sites (with storm sampling) and a 10-year period (2001-10) at 33 primary sites and 16 "secondary" sites (without storm sampling). In addition, loads at 64 primary sites were estimated for the period 2006 to 2010. Results indicate improving flow-adjusted trends for nitrogen and phosphorus for 1985 to 2010 at most of the sites in the network. For nitrogen, 21 of the 31 sites showed downward (improving) trends, whereas 2 sites showed upward (degrading) trends, and 8 sites showed no trends. The results for phosphorus were similar: 22 sites showed improving trends, 4 sites showed degrading trends, and 5 sites indicated no trends. For sediment, no trend was found at 40 percent of the sites, with 10 sites showing improving trends and 8 sites showing degrading trends. The USGS, working with CBP partners, developed a new water-quality indicator that combines the results of the 10-year trend

  15. Decadal re-evaluation of contaminant exposure and productivity of ospreys (Pandion haliaetus) nesting in Chesapeake Bay Regions of Concern

    International Nuclear Information System (INIS)

    The last large-scale ecotoxicological study of ospreys (Pandion haliaetus) in Chesapeake Bay was conducted in 2000–2001 and focused on U.S. EPA-designated Regions of Concern (ROCs; Baltimore Harbor/Patapsco, Anacostia/middle Potomac, and Elizabeth Rivers). In 2011–2012, ROCs were re-evaluated to determine spatial and temporal trends in productivity and contaminants. Concentrations of p,p′-DDE were low in eggs and below the threshold associated with eggshell thinning. Eggs from the Anacostia/middle Potomac Rivers had lower total PCB concentrations in 2011 than in 2000; however, concentrations remained unchanged in Baltimore Harbor. Polybrominated diphenyl ether flame retardants declined by 40%, and five alternative brominated flame retardants were detected at low levels. Osprey productivity was adequate to sustain local populations, and there was no relation between productivity and halogenated contaminants. Our findings document continued recovery of the osprey population, declining levels of many persistent halogenated compounds, and modest evidence of genetic damage in nestlings from industrialized regions. - Highlights: • This study documents the continued recovery of the Chesapeake Bay osprey population. • Osprey eggshells have nearly returned to pre-DDT-era thickness. • Organochlorine pesticides are low in eggs, but PCB levels seem unchanged in industrialized areas. • PBDE flame retardants have declined in eggs, but seem to peak near wastewater treatment plants. • There is some evidence of genetic damage in nestling blood samples in the most industrialized areas. - While the Chesapeake Bay osprey population has recovered, concentrations of some persistent contaminants in eggs remain unchanged, and there is some evidence of genetic damage in nestlings

  16. Non-stationary Concentration-Discharge Relationships for Nitrogen, Phosphorus, and Sediment for Nine Major Tributaries of the Chesapeake Bay

    Science.gov (United States)

    Zhang, Q.; Ball, W. P.

    2015-12-01

    Derived from river water-quality monitoring data, concentration-discharge (C-Q) relationships are a powerful tool for understanding nutrient and sediment dynamics. Here we first present a brief review of C-Q relationships documented in the scientific literature. Major categories of observed relationships for nutrient and sediment include: (a) "dilution" patterns (i.e., negative C-Q relationships), particularly for point-source dominated rivers; and (b) "concentration" patterns (i.e., positive C-Q relationships), particularly for nonpoint-source dominated rivers. In the second part of our work, we present a comprehensive evaluation of riverine C-Q patterns for multiple water-quality constituents for the nine major non-tidal tributaries of the Chesapeake Bay. Specifically, we have analyzed concentration data sets of total nitrogen, nitrate plus nitrite, total phosphorus, dissolved orthophosphate, and suspended sediment for the period between the 1980s and 2015. Separation of the monitoring data into non-overlapping decadal periods revealed clear non-stationarity in C-Q relationships for many of the selected site-constituent combinations. These temporal changes in C-Q relationships generally reflected changes in dominant watershed sources of nutrients and sediment (e.g., reduction in point-source dominance for total nitrogen in the Patuxent River due to technology upgrade at wastewater treatment plants) and are consistent with trends observed in previous research. The findings also highlight the potential pitfalls of assuming stationary C-Q relationships when estimating riverine concentrations and fluxes or analyzing their trends.

  17. Quantifying early 17th century changes in Chesapeake Bay estuarine carbon dynamics from James River, VA oyster geochemistry

    Science.gov (United States)

    Grimm, B. L.; Spero, H. J.; Harding, J. M.

    2012-12-01

    The first successful European colonization of North America occurred in 1607 following the arrival of English settlers at Jamestown, Virginia. Within a few decades, land use changes and clear-cutting farming practices dramatically altered the terrestrial landscape and removed the overlying canopy and stabilizing root network of the previously-dominant hardwood forests. The Eastern oyster, Crassostrea virginica, has inhabited the Chesapeake Bay since the end of the last deglaciation. During the start of the Jamestown Colony, an extensive drought (1606-1612) shifted James River salinity zones upriver, expanding the available oyster habitat to the vicinity of Jamestown. This allowed the colonists to collect and eat oysters from areas near the colony down to the river's entry into the bay, and later discard the shells in wells and trash pits that have recently been excavated. The oysters' calcium carbonate shells discovered in these deposits act as multi-year stationary recorders preserving the local environmental chemistry throughout their life until collection. Here we present δ13C, δ18O, and radiocarbon data from historical oyster shell hinge transects that encompass the time period between ~1609 and the early 1700s. Samples include shells from the 1609 Jamestown freshwater well and five additional sites, as well as modern shells collected in 2006. Because shell δ13C and radiocarbon (14C) reflect James River δ13CDIC, it is possible to document carbon source changes during this period of land use change. Our preliminary data suggest a decrease in ambient δ13CDIC of approximately 2‰ between just prior to 1609 conditions and the modern estuary. This is most likely due to an increase in isotopically light organic carbon loading into the river as water moves more rapidly through the terrestrial system. Radiocarbon reservoir ages will also be presented to better constrain carbon flow through the system during this period of disturbance. δ18O measurements from the

  18. Quantitative Models for the Narragansett Bay Estuary, Rhode Island/Massachusetts, USA

    Science.gov (United States)

    Multiple drivers, including nutrient loading and climate change, affect the Narragansett Bay ecosystem in Rhode Island/Massachusetts, USA. Managers are interested in understanding the timing and magnitude of these effects, and ecosystem responses to restoration actions. To provid...

  19. Nutrient Trading, the Flush Tax, and Maryland's Nitrogen Emissions to the Chesapeake Bay

    OpenAIRE

    Hanson, James C.; McConnell, Kenneth E.

    2007-01-01

    We investigate nutrient trading for point and non-point sources for the Bay Restoration Fund in Maryland. We demonstrate how to use the proceeds from the tax revenue to mimic trading high-cost upgrades of sewage treatment plants for low-cost winter cover crops. Under an optimistic assumption about costs for non-point sources, we calculate that abatement could be increased by more than 50%, while in a pessimistic scenario, abatement could be increased by 2%. We also explore the role of uncerta...

  20. Concentrations of metals in feathers and blood of nestling Black-Crowned Night-Herons (Nycticorax nycticorax) in Chesapeake and Delaware Bays

    Science.gov (United States)

    Golden, N.H.; Rattner, B.A.; McGowan, P.C.; Parsons, K.C.; Ottinger, M.A.

    2003-01-01

    Over the past decade, destruction and degradation of wetland habitat has contributed to the decline of wading bird colonies on the Atlantic Coast. In 1998, an initial assessment of the possible contribution of metal pollution to declining heron populations in Chesapeake and Delaware Bays was conducted. Study sites included two heronries in industrialized locations (Pea Patch Island, DE and Baltimore Harbor, MD), and a reference site (Holland Island) remotely located in the southern Chesapeake Bay. Concentrations of 19 metals, metalloids, and trace elements were examined in blood and breast feathers of 14-16 day old nestling black-crowned night-herons. Metal concentrations in blood were low and showed few site differences, though mercury was elevated at Pea Patch Island as compared to other sites. In feathers, metal concentrations appeared to be in the low to moderate range at all sites, though limited data exist for interpreting pollutant concentrations in feathers of nestling wading birds. Where differences were detected, concentrations at Pea Patch Island were consistently greater than those at Baltimore Harbor and Holland Island. Feathers collected at Pea Patch Island had significantly greater concentrations of aluminum, barium, iron, lead, magnesium, and manganese, but were generally found to be within the range of concentrations detected in other nestling birds, where that information was available. Based on these results, metal pollution does not appear to be an immediate threat to BCNH colonies at these two locations, though future monitoring of some elements (Pb, Mn, and Al) may be warranted.

  1. Nutrient and physical profile data from four Microbial Exchanges and Coupling in Coastal Atlantic Systems (MECCAS) cruises collected aboard the R/V Gyre at the mouth of the Chesapeake Bay and northern Atlantic Ocean from February 17, 1985 to September 7, 1986 (NODC Accession 8800324)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Microbial Exchanges and Coupling in Coastal Atlantic Systems (MECCAS) cruise data collected aboard the R/V Gyre at the mouth of the Chesapeake Bay and northern...

  2. Spatial Statistical Network Models for Stream and River Temperature in the Chesapeake Bay Watershed, USA

    Science.gov (United States)

    Regional temperature models are needed for characterizing and mapping stream thermal regimes, establishing reference conditions, predicting future impacts and identifying critical thermal refugia. Spatial statistical models have been developed to improve regression modeling techn...

  3. Puente-túnel de la Bahía de Chesapeake, (U.S.A.

    Directory of Open Access Journals (Sweden)

    Sverdrup, Leif J.

    1966-11-01

    Full Text Available The total project involves 20 km of road over shallow waters two tunnels, each 1,500 m long, two bridges, four artificial islands, 2,000 m of road over dykes, and approximately 9 km of approach roads. The total length of the work is 26 km, and the width of the pavement is 8.50 m. The supports for the elevated road, over the bay water, consist of palisades of three cylindrical, reinforced concrete, piles, connected with a cross member. The two underwater tunnels were prefabricated in sections, at the workshop, and were then transported in pontoons, and placed at the bottom of a trench, which had been previously dredged out. Finally the joints were sealed, and the diaphragms which initially closed the ends of each section were opened, when the structure was in its final position. The project is undoubtedly interesting because of its variety, size and length, and also on account of the difficulties of undertaking the sea works in relatively deep waters.El conjunto se compone de 20 km de paso superior, dos túneles de 1.500 m, dos puentes propiamente dichos, cuatro islas artificiales, 2.000 m de carretera sobre diques y aproximadamente 9 km de caminos de acceso. La obra tiene una longitud total de 26 km y la anchura de la calzada es de 8,50 m. Los soportes del paso superior están constituidos por palizadas de tres pilotes, cilíndricos, de hormigón armado, arriostrados con un cabezal. Los dos túneles se prefabricaron por trozos, en taller, los cuales fueron transportados por medio de pontones, colocados en el fondo de una trinchera previamente dragada y, finalmente, selladas las juntas y abiertos los diafragmas que originalmente cerraban los extremos de cada trozo, antes del hundimiento en su posición definitiva. La obra es de indudable interés por su variedad, volumen y longitud y por las dificultades que entraña el realizar trabajos marítimos en aguas relativamente profundas.

  4. Application of geologic map information to water quality issues in the southern part of the Chesapeake Bay watershed, Maryland and Virginia, eastern United States

    Science.gov (United States)

    McCartan, L.; Peper, J.D.; Bachman, L.J.; Horton, J.W., Jr.

    1999-01-01

    Geologic map units contain much information about the mineralogy, chemistry, and physical attributes of the rocks mapped. This paper presents information from regional-scale geologic maps in Maryland and Virginia, which are in the southern part of the Chesapeake Bay watershed in the eastern United States. The geologic map information is discussed and analyzed in relation to water chemistry data from shallow wells and stream reaches in the area. Two environmental problems in the Chesapeake Bay watershed are used as test examples. The problems, high acidity and high nitrate concentrations in streams and rivers, tend to be mitigated by some rock and sediment types and not by others. Carbonate rocks (limestone, dolomite, and carbonate-cemented rocks) have the greatest capacity to neutralize acidic ground water and surface water in contact with them. Rocks and sediments having high carbon or sulfur contents (such as peat and black shale) potentially contribute the most toward denitrification of ground water and surface water in contact with them. Rocks and sediments that are composed mostly of quartz, feldspar, and light-colored clay (rocks such as granite and sandstone, sediments such as sand and gravel) tend not to alter the chemistry of waters that are in contact with them. The testing of relationships between regionally mapped geologic units and water chemistry is in a preliminary stage, and initial results are encouraging.Geologic map units contain much information about the mineralogy, chemistry, and physical attributes of the rocks mapped. This paper presents information from regional-scale geologic maps in Maryland and Virginia, which are in the southern part of the Chesapeake Bay watershed in the eastern United States. The geologic map information is discussed and analyzed in relation to water chemistry data from shallow wells and stream reaches in the area. Two environmental problems in the Chesapeake Bay watershed are used as test examples. The problems, high

  5. BENTHIC MACROFAUNA-HABITAT ASSOCIATIONS IN WILLAPA BAY, WASHINGTON, USA

    Science.gov (United States)

    Estuary-wide benthic macrofauna-habitat associations in Willapa Bay, Washington, United States, were determined for 4 habitats (eelgrass [Zostera marina], Atlantic cordgrass [Spartina alterniflora], mud shrimp [Upogebia pugettensis], ghost shrimp [Neotrypaea californiensis]) in 1...

  6. A rapid procedure for the determination of thorium, uranium, cadmium and molybdenum in small sediment samples by inductively coupled plasma-mass spectrometry: Application in Chesapeake Bay

    Science.gov (United States)

    Zheng, Yen; Weinman, B.; Cronin, T.; Fleisher, M.Q.; Anderson, Robert F.

    2003-01-01

    This paper describes a rapid procedure that allows precise analysis of Mo, Cd, U and Th in sediment samples as small as 10 mg by using a novel approach that utilizes a "pseudo" isotope dilution for Th and conventional isotope dilution for Mo, Cd and U by ICP-MS. Long-term reproducibility of the method is between 2.5 and 5% with an advantage of rapid analysis on a single digestion of sediment sample and the potential of adding other elements of interest if so desired. Application of this method to two piston cores collected near the mouth of the Patuxent River in Chesapeake Bay showed that the accumulation of authigenic Mo and Cd varied in response to the changing bottom water redox conditions, with anoxia showing consistent oscillations throughout both pre-industrial and industrial times. Accumulation of authigenic U shows consistent oscillations as well, without any apparent increase in productivity related to anoxic trends. Degrees of Mo and Cd enrichment also inversely correlate to halophilic microfaunal assemblages already established as paleoclimate proxies within the bay indicating that bottom water anoxia is driven in part by the amount of freshwater discharge that the area receives. ?? 2002 Elsevier Science Ltd. All rights reserved.

  7. A rapid procedure for the determination of thorium, uranium, cadmium and molybdenum in small sediment samples by inductively coupled plasma-mass spectrometry: application in Chesapeake Bay

    International Nuclear Information System (INIS)

    This paper describes a rapid procedure that allows precise analysis of Mo, Cd, U and Th in sediment samples as small as 10 mg by using a novel approach that utilizes a 'pseudo' isotope dilution for Th and conventional isotope dilution for Mo, Cd and U by ICP-MS. Long-term reproducibility of the method is between 2.5 and 5% with an advantage of rapid analysis on a single digestion of sediment sample and the potential of adding other elements of interest if so desired. Application of this method to two piston cores collected near the mouth of the Patuxent River in Chesapeake Bay showed that the accumulation of authigenic Mo and Cd varied in response to the changing bottom water redox conditions, with anoxia showing consistent oscillations throughout both pre-industrial and industrial times. Accumulation of authigenic U shows consistent oscillations as well, without any apparent increase in productivity related to anoxic trends. Degrees of Mo and Cd enrichment also inversely correlate to halophilic microfaunal assemblages already established as paleoclimate proxies within the bay indicating that bottom water anoxia is driven in part by the amount of freshwater discharge that the area receives

  8. Assessment of sediment contamination in Casco Bay, Maine, USA

    International Nuclear Information System (INIS)

    The current status of contaminant concentrations in Casco Bay, decadal trends of these contaminants and changes in their geographical distribution are assessed using sediment samples collected approximately 10 years apart. In general, regulated contaminants appeared to be decreasing in concentration. Total PAH and dioxins/furans concentrations did not significantly change over this period. Total organochlorine pesticides, 4,4-DDE, 4,4-DDD, total DDT, PCB, tributyltin and total butyltin decreased in concentration. Trace element concentrations in sediments decreased at the majority of the sampling sites for chromium, nickel, and selenium while arsenic, cadmium, copper, lead, mercury, silver, and zinc remained relatively constant. None of the contaminants measured has increased by more than a factor of 2. Selected sites located in the Inner Bay, where concentrations are higher and new inputs were more likely, showed increased concentrations of contaminants. Most contaminants were not found at concentrations expected to adversely affect sediment biota based on ERL/ERM guidelines. - Sediment studies indicate decadal decreases for many chemical contaminants in Casco Bay

  9. Diffusive exchange of polycyclic aromatic hydrocarbons across the air-water interface of the Patapsco River, an urbanized subestuary of the Chesapeake Bay

    Energy Technology Data Exchange (ETDEWEB)

    Bamford, H.A.; Offenberg, J.H.; Larsen, R.K.; Ko, F.C.; Baker, J.E. [Univ. of Maryland, Solomons, MD (United States)

    1999-07-01

    Air-water exchange fluxes of 13 polycyclic aromatic hydrocarbons (PAHs) were determined along a transect in the Patapsco River from the Inner Harbor of Baltimore, MD, to the mainstem of the northern Chesapeake Bay. Sampling took place at six sites during three sampling intensives (June 1996, February 1997, and July 1997) and at one site every ninth day between March 1997 and March 1998 to measure spatial, daily, and annual variability in the fluxes. The direction and magnitude of the daily fluxes of individual PAHs were strongly influenced by the wind speed and direction, by the air temperature, and by the highly variable PAH concentrations in the gas and dissolved phases. Individual fluxes ranged from 14,200 ng m{sup {minus}2} day{sup {minus}1} net volatilization of fluorene during high winds to 11,400 ng m{sup {minus}2} day{sup {minus}1} net absorption of phenanthrene when prevailing winds blowing from the northwest across the city of Baltimore elevated gaseous PAH concentrations over the water. The largest PAH volatilization fluxes occurred adjacent to the stormwater discharges, driven by elevated dissolved PAH concentrations in surface waters. Estimated annual volatilization fluxes ranged from 1.1 {micro}g m{sup {minus}2} yr{sup {minus}1} for chrysene to 800 {micro}g m{sup {minus}2} yr{sup {minus}1} for fluorene.

  10. Shifts in Cyanobacterial Strain Dominance during the Onset of Harmful Algal Blooms in Florida Bay, USA.

    Science.gov (United States)

    Berry, Dianna L; Goleski, Jennifer A; Koch, Florian; Wall, Charles C; Peterson, Bradley J; Anderson, O Roger; Gobler, Christopher J

    2015-08-01

    Cyanobacteria are fundamental components of aquatic phytoplankton communities and some taxa can cause harmful blooms in coastal ecosystems. Harmful cyanobacterial blooms are typically comprised of multiple strains of a single genus or species that cannot be resolved microscopically. Florida Bay, USA, has experienced harmful cyanobacterial blooms that have been associated with the loss of eelgrass, spiny lobsters, and general food web disruption for more than two decades. To identify the strain or strains of cyanobacteria forming blooms in Florida Bay, samples were collected across the system over an annual cycle and analyzed via DNA sequencing using cyanobacterial-specific 16S rRNA gene primers, flow cytometry, and scanning electron microscopy. Analyses demonstrated that the onset of blooms in Florida Bay was coincident with a transformation of the cyanobacterial populations. When blooms were absent, the cyanobacterial population in Florida Bay was dominated by phycoerythrin-containing Synechococcus cells that were most similar to strains within Clade III. As blooms developed, the cyanobacterial community transitioned to dominance by phycocyanin-containing Synechococcus cells that were coated with mucilage, chain-forming, and genetically most similar to the coastal strains within Clade VIII. Clade VIII strains of Synechococcus are known to grow rapidly, utilize organic nutrients, and resist top-down control by protozoan grazers and viruses, all characteristics consistent with observations of cyanobacterial blooms in Florida Bay. Further, the strains of Synechococcus blooming in this system are genetically distinct from the species previously thought to cause blooms in Florida Bay, Synechococcus elongatus. Collectively, this study identified the causative organism of harmful cyanobacterial blooms in Florida Bay, demonstrates the dynamic nature of cyanobacterial stains within genera in an estuary, and affirms factors promoting Synechococcus blooms. PMID:25661475

  11. Rising sea level, temperature, and precipitation impact plant and ecosystem responses to elevated CO2 on a Chesapeake Bay wetland: review of a 28-year study.

    Science.gov (United States)

    Drake, Bert G

    2014-11-01

    An ongoing field study of the effects of elevated atmospheric CO2 on a brackish wetland on Chesapeake Bay, started in 1987, is unique as the longest continually running investigation of the effects of elevated CO2 on an ecosystem. Since the beginning of the study, atmospheric CO2 increased 18%, sea level rose 20 cm, and growing season temperature varied with approximately the same range as predicted for global warming in the 21st century. This review looks back at this study for clues about how the effects of rising sea level, temperature, and precipitation interact with high atmospheric CO2 to alter the physiology of C3 and C4 photosynthetic species, carbon assimilation, evapotranspiration, plant and ecosystem nitrogen, and distribution of plant communities in this brackish wetland. Rising sea level caused a shift to higher elevations in the Scirpus olneyi C3 populations on the wetland, displacing the Spartina patens C4 populations. Elevated CO2 stimulated carbon assimilation in the Scirpus C3 species measured by increased shoot and root density and biomass, net ecosystem production, dissolved organic and inorganic carbon, and methane production. But elevated CO2 also decreased biomass of the grass, S. patens C4. The elevated CO2 treatment reduced tissue nitrogen concentration in shoots, roots, and total canopy nitrogen, which was associated with reduced ecosystem respiration. Net ecosystem production was mediated by precipitation through soil salinity: high salinity reduced the CO2 effect on net ecosystem production, which was zero in years of severe drought. The elevated CO2 stimulation of shoot density in the Scirpus C3 species was sustained throughout the 28 years of the study. Results from this study suggest that rising CO2 can add substantial amounts of carbon to ecosystems through stimulation of carbon assimilation, increased root exudates to supply nitrogen fixation, reduced dark respiration, and improved water and nitrogen use efficiency. PMID:24820033

  12. A regional mass balance of methylmercury in San Francisco Bay, California, USA.

    Science.gov (United States)

    Yee, Donald; McKee, Lester J; Oram, John J

    2011-01-01

    The San Francisco Bay (California, USA) is a water body listed as impaired because of Hg contamination in sport fish for human consumption, as well as possible effects on resident wildlife. A legacy of Hg mining in local watersheds and Hg used in Au mining in the Sierra Nevada (USA) has contributed to contamination seen in the bay, with additional more recent and ongoing inputs from various sources. Methylmercury is the species of Hg most directly responsible for contamination in biota, so better understanding of its sources, loads, and processes was sought to identify the best means to reduce impacts. A regional scale model of San Francisco Bay was developed to characterize major methylmercury inputs and processes. The model was used to evaluate the potential impact of uncertainties in estimates for methylmercury loading pathways and environmental processes, identify major data gaps, and explore management prospects for reducing methylmercury contamination. External loading pathways considered in the mass balance include methylmercury loads entering via atmospheric deposition to the bay surface, and discharges from the Sacramento/San Joaquin Delta, local watersheds, municipal wastewater, and fringing wetlands. Internal processes considered include exchange between bed and suspended sediments and the water column, in situ production and demethylation, biological uptake, and losses via hydrologic transport to the ocean through the Golden Gate. In situ sediment methylation and demethylation were dominant sources and losses determining ambient steady-state concentrations in the model, with changes in external loads and export causing smaller changes. Better information on methylation and demethylation is thus most critical to improving understanding of methylmercury balances and management. PMID:20872899

  13. Selenium bioaccumulation and body condition in shorebirds and terns breeding in San Francisco Bay, California, USA.

    Science.gov (United States)

    Ackerman, Joshua T; Eagles-Smith, Collin A

    2009-10-01

    The present study evaluated Se bioaccumulation in four waterbird species (n=206 birds) that breed within San Francisco Bay, California, U.S.A.: American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster's terns (Sterna forsteri), and Caspian terns (Hydroprogne caspia). Selenium concentrations were variable and influenced by several factors, including species, region, reproductive stage, age, and sex. Adult Se concentrations (microg/g dry wt) in livers ranged from 3.07 to 48.70 in avocets (geometric mean +/- standard error, 7.92 +/- 0.64), 2.28 to 41.10 in stilts (5.29 +/- 0.38), 3.73 to 14.50 in Forster's terns (7.13 _ 0.38), and 4.77 to 14.40 in Caspian terns (6.73 +/- 0.78). Avocets had higher Se concentrations in the North Bay compared to the South Bay, whereas stilt Se concentrations were similar between these regions and Forster's terns had lower Se concentrations in the North Bay compared to the South Bay. Female avocets had higher Se concentrations than male avocets, but this was not the case for stilts and Forster's terns. Of the factors assessed, reproductive stage had the most consistent effect among species. Prebreeding birds tended to have higher liver Se concentrations than breeding birds, but this trend was statistically significant only for Forster's terns. Forster's tern chicks had lower Se concentrations than Forster's tern adults, whereas avocet and stilt adults and chicks were similar. Additionally, body condition was negatively related to liver Se concentrations in Forster's tern adults but not in avocet, stilt, or Caspian tern adults and chicks. These variable results illustrate the complexity of Se bioaccumulation and highlight the need to sample multiple species and examine several factors to assess the impact of Se on wildlife. PMID:19459720

  14. Chesapeake Bay Climate Study Partnership: Undergraduate Student Experiential Learning on Microclimates at the University of Hawai'i, Hilo

    Science.gov (United States)

    Ozbay, G.; Sriharan, S.; Fan, C.; Adolf, J.

    2015-12-01

    Undergraduate student experiential learning activities focused on microclimates of Hawai'i Island, Hawai'i. Six students from Virginia State University, three students from Delaware State University and faculty advisors were hosted by the University of Hawai'i at Hilo (UHH) Department of Marine Science. This partnership provided integrated, cohesive, and innovative education and research capabilities to minority students on climate change science. Activities included a summer course, instrumentation training, field and laboratory research training, sampling, data collection, logging, analysis, interpretation, report preparation, and research presentation. Most training activities used samples collected during students' field sampling in Hilo Bay. Water quality and phytoplankton data were collected along a 220 degree line transect from the mouth of the Wailuku River to the pelagic zone outside of Hilo Bay into the Pacific Ocean to a distance of 15.5 km. Water clarity, turbidity, chlorophyll, physical water quality parameters, and atmospheric CO2 levels were measured along the transect. Phytoplankton samples were collected for analysis by Scanning Electron Microscopy and Flow Cytometry. Data showed the extent of anthropogenic activity on water quality, with implications for food web dynamics. In addition, atmospheric CO2 concentration, island vegetation, and GPS points were recorded throughout the island of Hawai'i to investigate how variations in microclimate, elevation, and land development affect the amount of CO2 in the atmosphere, vegetation, and water quality. Water quality results at locations near rivers were completely different from other study sites, requiring students' critical thinking skills to find possible reasons for the difference. Our data show a correlation between population density and CO2 concentrations. Anthropogenic activities affecting CO2 and ocean conditions in Hawaiian microclimates can potentially have deleterious effects on the life

  15. Conductivity, temperature, depth, fluorescence, optical backscatter, laser in-situ scattering and transmissivity, acoustic zooplankton biomass, net zooplankton counts, and suspended particle data from the RV HUGH R. SHARP in the upper Chesapeake Bay from February 23 through 26, 2007 as part of the Bio-Physical Interaction in the Turbidity Maximum (BITMAX-II) program (NODC Accession 0062884)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data set contains Cruise Reports and CTD data from 8 main cruises in the upper Chesapeake Bay on board the R/V Hugh R. Sharp from February 2007 to October 2008 ....

  16. Application of a Weighted Regression Model for Reporting Nutrient and Sediment Concentrations, Fluxes, and Trends in Concentration and Flux for the Chesapeake Bay Nontidal Water-Quality Monitoring Network, Results Through Water Year 2012

    Science.gov (United States)

    Chanat, Jeffrey G.; Moyer, Douglas L.; Blomquist, Joel D.; Hyer, Kenneth E.; Langland, Michael J.

    2016-01-01

    In the Chesapeake Bay watershed, estimated fluxes of nutrients and sediment from the bay’s nontidal tributaries into the estuary are the foundation of decision making to meet reductions prescribed by the Chesapeake Bay Total Maximum Daily Load (TMDL) and are often the basis for refining scientific understanding of the watershed-scale processes that influence the delivery of these constituents to the bay. Two regression-based flux and trend estimation models, ESTIMATOR and Weighted Regressions on Time, Discharge, and Season (WRTDS), were compared using data from 80 watersheds in the Chesapeake Bay Nontidal Water-Quality Monitoring Network (CBNTN). The watersheds range in size from 62 to 70,189 square kilometers and record lengths range from 6 to 28 years. ESTIMATOR is a constant-parameter model that estimates trends only in concentration; WRTDS uses variable parameters estimated with weighted regression, and estimates trends in both concentration and flux. WRTDS had greater explanatory power than ESTIMATOR, with the greatest degree of improvement evident for records longer than 25 years (30 stations; improvement in median model R2= 0.06 for total nitrogen, 0.08 for total phosphorus, and 0.05 for sediment) and the least degree of improvement for records of less than 10 years, for which the two models performed nearly equally. Flux bias statistics were comparable or lower (more favorable) for WRTDS for any record length; for 30 stations with records longer than 25 years, the greatest degree of improvement was evident for sediment (decrease of 0.17 in median statistic) and total phosphorus (decrease of 0.05). The overall between-station pattern in concentration trend direction and magnitude for all constituents was roughly similar for both models. A detailed case study revealed that trends in concentration estimated by WRTDS can operationally be viewed as a less-constrained equivalent to trends in concentration estimated by ESTIMATOR. Estimates of annual mean flow

  17. Impacts of Watershed Characteristics and Crop Rotations on Winter Cover Crop Nitrate-Nitrogen Uptake Capacity within Agricultural Watersheds in the Chesapeake Bay Region.

    Directory of Open Access Journals (Sweden)

    Sangchul Lee

    Full Text Available The adoption rate of winter cover crops (WCCs as an effective conservation management practice to help reduce agricultural nutrient loads in the Chesapeake Bay (CB is increasing. However, the WCC potential for water quality improvement has not been fully realized at the watershed scale. This study was conducted to evaluate the long-term impact of WCCs on hydrology and NO3-N loads in two adjacent watersheds and to identify key management factors that affect the effectiveness of WCCs using the Soil and Water Assessment Tool (SWAT and statistical methods. Simulation results indicated that WCCs are effective for reducing NO3-N loads and their performance varied based on planting date, species, soil characteristics, and crop rotations. Early-planted WCCs outperformed late-planted WCCs on the reduction of NO3-N loads and early-planted rye (RE reduced NO3-N loads by ~49.3% compared to the baseline (no WCC. The WCCs were more effective in a watershed dominated by well-drained soils with increased reductions in NO3-N fluxes of ~2.5 kg N·ha-1 delivered to streams and ~10.1 kg N·ha-1 leached into groundwater compared to poorly-drained soils. Well-drained agricultural lands had higher transport of NO3-N in the soil profile and groundwater due to increased N leaching. Poorly-drained agricultural lands had lower NO3-N due to extensive drainage ditches and anaerobic soil conditions promoting denitrification. The performance of WCCs varied by crop rotations (i.e., continuous corn and corn-soybean, with increased N uptake following soybean crops due to the increased soil mineral N availability by mineralization of soybean residue compared to corn residue. The WCCs can reduce N leaching where baseline NO3-N loads are high in well-drained soils and/or when residual and mineralized N availability is high due to the cropping practices. The findings suggested that WCC implementation plans should be established in watersheds according to local edaphic and agronomic

  18. Impact of storm-water outfalls on sediment quality in Corpus Christi Bay, Texas, USA

    Energy Technology Data Exchange (ETDEWEB)

    Carr, R.S.; Montagna, P.A.; Biedenbach, J.M.; Kalke, R.; Kennicutt, M.C.; Hooten, R.; Cripe, G.

    2000-03-01

    To determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm-water outfalls, but 13 other sites (i.e., industrial and domestic outfalls, oil field-produced water discharges, and dredging activity) and eight reference sites were also evaluated. Sediment samples were collected and analyzed for physical-chemical characteristics, contaminant concentrations (metals, polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and pesticides), toxicity, and a benthic index of biotic integrity (BIBI) composed of 10 independent metrics calculated for each site. This large data matrix was reduced using multivariate analysis to create new variables for each component representing overall means and containing most of the variance in the larger data set. The new variables were used to conduct the correlation analysis. Toxicity was significantly correlated with both chemistry and ecological responses, whereas no correlations between the benthic metrics and sediment chemistry were observed. Using the combined information from the SQT, four of the five most degraded sites were storm-water outfall sites. Although estuaries are naturally stressful environments because of salinity and temperature fluctuations, this ecosystem appears to have been compromised by anthropogenic influences similar to what has been observed for other heavily urbanized bay systems along the Texas and Gulf coast.

  19. 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.

  20. Bed composition generation for morphodynamic modeling: Case study of San Pablo Bay in California, USA

    Science.gov (United States)

    van der Wegen, M.; Dastgheib, A.; Jaffe, B.E.; Roelvink, D.

    2011-01-01

    Applications of process-based morphodynamic models are often constrained by limited availability of data on bed composition, which may have a considerable impact on the modeled morphodynamic development. One may even distinguish a period of "morphodynamic spin-up" in which the model generates the bed level according to some ill-defined initial bed composition rather than describing the realistic behavior of the system. The present paper proposes a methodology to generate bed composition of multiple sand and/or mud fractions that can act as the initial condition for the process-based numerical model Delft3D. The bed composition generation (BCG) run does not include bed level changes, but does permit the redistribution of multiple sediment fractions over the modeled domain. The model applies the concept of an active layer that may differ in sediment composition above an underlayer with fixed composition. In the case of a BCG run, the bed level is kept constant, whereas the bed composition can change. The approach is applied to San Pablo Bay in California, USA. Model results show that the BCG run reallocates sand and mud fractions over the model domain. Initially, a major sediment reallocation takes place, but development rates decrease in the longer term. Runs that take the outcome of a BCG run as a starting point lead to more gradual morphodynamic development. Sensitivity analysis shows the impact of variations in the morphological factor, the active layer thickness, and wind waves. An important but difficult to characterize criterion for a successful application of a BCG run is that it should not lead to a bed composition that fixes the bed so that it dominates the "natural" morphodynamic development of the system. Future research will focus on a decadal morphodynamic hindcast and comparison with measured bathymetries in San Pablo Bay so that the proposed methodology can be tested and optimized. ?? 2010 The Author(s).

  1. Automated feature extraction and spatial organization of seafloor pockmarks, Belfast Bay, Maine, USA

    Science.gov (United States)

    Andrews, B.D.; Brothers, L.L.; Barnhardt, W.A.

    2010-01-01

    Seafloor pockmarks occur worldwide and may represent millions of m3 of continental shelf erosion, but few numerical analyses of their morphology and spatial distribution of pockmarks exist. We introduce a quantitative definition of pockmark morphology and, based on this definition, propose a three-step geomorphometric method to identify and extract pockmarks from high-resolution swath bathymetry. We apply this GIS-implemented approach to 25km2 of bathymetry collected in the Belfast Bay, Maine USA pockmark field. Our model extracted 1767 pockmarks and found a linear pockmark depth-to-diameter ratio for pockmarks field-wide. Mean pockmark depth is 7.6m and mean diameter is 84.8m. Pockmark distribution is non-random, and nearly half of the field's pockmarks occur in chains. The most prominent chains are oriented semi-normal to the steepest gradient in Holocene sediment thickness. A descriptive model yields field-wide spatial statistics indicating that pockmarks are distributed in non-random clusters. Results enable quantitative comparison of pockmarks in fields worldwide as well as similar concave features, such as impact craters, dolines, or salt pools. ?? 2010.

  2. Development of Relations of Stream Stage to Channel Geometry and Discharge for Stream Segments Simulated with Hydrologic Simulation Program-Fortran (HSPF), Chesapeake Bay Watershed and Adjacent Parts of Virginia, Maryland, and Delaware

    Science.gov (United States)

    Moyer, Douglas; Bennett, Mark

    2007-01-01

    The U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (USEPA), Chesapeake Bay Program (CBP), Interstate Commission for the Potomac River Basin (ICPRB), Maryland Department of the Environment (MDE), Virginia Department of Conservation and Recreation (VADCR), and University of Maryland (UMD) are collaborating to improve the resolution of the Chesapeake Bay Regional Watershed Model (CBRWM). This watershed model uses the Hydrologic Simulation Program-Fortran (HSPF) to simulate the fate and transport of nutrients and sediment throughout the Chesapeake Bay watershed and extended areas of Virginia, Maryland, and Delaware. Information from the CBRWM is used by the CBP and other watershed managers to assess the effectiveness of water-quality improvement efforts as well as guide future management activities. A critical step in the improvement of the CBRWM framework was the development of an HSPF function table (FTABLE) for each represented stream channel. The FTABLE is used to relate stage (water depth) in a particular stream channel to associated channel surface area, channel volume, and discharge (streamflow). The primary tool used to generate an FTABLE for each stream channel is the XSECT program, a computer program that requires nine input variables used to represent channel morphology. These input variables are reach length, upstream and downstream elevation, channel bottom width, channel bankfull width, channel bankfull stage, slope of the floodplain, and Manning's roughness coefficient for the channel and floodplain. For the purpose of this study, the nine input variables were grouped into three categories: channel geometry, Manning's roughness coefficient, and channel and floodplain slope. Values of channel geometry for every stream segment represented in CBRWM were obtained by first developing regional regression models that relate basin drainage area to observed values of bankfull width, bankfull depth, and bottom width at each of the 290 USGS

  3. Validation of MODIS FLH and In Situ Chlorophyll a from Tampa Bay, Florida (USA)

    Science.gov (United States)

    Fischer, Andrew; MorenoMadrinan, Max J.

    2012-01-01

    Satellite observation of phytoplankton concentration or chlorophyll-a (chla) is an important characteristic, critically integral to monitoring coastal water quality. However, the optical properties of estuarine and coastal waters are highly variable and complex and pose a great challenge for accurate analysis. Constituents such as suspended solids and dissolved organic matter and the overlapping and uncorrelated absorptions in the blue region of the spectrum renders the blue-green ratio algorithms for estimating chl-a inaccurate. Measurement of suninduced chlorophyll fluorescence, on the other hand, which utilizes the near infrared portion of the electromagnetic spectrum may, provide a better estimate of phytoplankton concentrations. While modelling and laboratory studies have illustrated both the utility and limitations of satellite algorithms based on the sun induced chlorophyll fluorescence signal, few have examined the empirical validity of these algorithms or compared their accuracy against bluegreen ratio algorithms . In an unprecedented analysis using a long term (2003-2011) in situ monitoring data set from Tampa Bay, Florida (USA), we assess the validity of the FLH product from the Moderate Resolution Imaging Spectrometer against a suite of water quality parameters taken in a variety of conditions throughout this large optically complex estuarine system. . Overall, the results show a 106% increase in the validity of chla concentration estimation using FLH over the standard chla estimate from the blue-green OC3M algorithm. Additionally, a systematic analysis of sampling sites throughout the bay is undertaken to understand how the FLH product responds to varying conditions in the estuary and correlations are conducted to see how the relationships between satellite FLH and in situ chlorophyll-a change with depth, distance from shore, from structures like bridges, and nutrient concentrations and turbidity. Such analysis illustrates that the correlations between

  4. Some challenges of an 'upside down' nitrogen budget - Science and management in Greenwich Bay, RI (USA)

    International Nuclear Information System (INIS)

    Research highlights: → Nutrient budget found most nitrogen to Greenwich Bay, RI is from adjacent estuary. → Water, plants, and animals in Greenwich Bay all have similar high stable isotope values. → Flux weighted isotope budgets find 50-80% of nitrogen in clams from adjacent bay. - Abstract: When nutrients impact estuarine water quality, scientists and managers instinctively focus on quantifying and controlling land-based sources. However, in Greenwich Bay, RI, the estuary opens onto a larger and more intensively fertilized coastal water body (Narragansett Bay). Previous inventories of nitrogen (N) inputs to Greenwich Bay found that N inputs from Narragansett Bay exceeded those from the local watershed, suggesting that recent efforts to reduce local watershed N loads may have little effect on estuarine water quality. We used stable isotopes of N to characterize watershed and Narragansett Bay N sources as well as the composition of primary producers and consumers throughout Greenwich Bay. Results were consistent with previous assessments of the importance of N inputs to Greenwich Bay from Narragansett Bay. As multiple N sources contribute to estuarine water quality, effective management requires attention to individual sources commensurate with overall magnitude, regardless of the political complications that may entail.

  5. Mercury correlations among six tissues for four waterbird species breeding in San Francisco Bay, California, USA.

    Science.gov (United States)

    Eagles-Smith, Collin A; Ackerman, Joshua T; Adelsbach, Terrence L; Takekawa, John Y; Miles, A Keith; Keister, Robin A

    2008-10-01

    Despite a large body of research concerning mercury (Hg) in birds, no single tissue has been used consistently to assess Hg exposure, and this has hampered comparisons across studies. We evaluated the relationships of Hg concentrations among tissues in four species of waterbirds (American avocets [Recurvirostra americana], black-necked stilts [Himantopus mexicanus], Caspian terns [Hydroprogne caspia; formerly Sterna caspia], and Forster's terns [Sterna forsteri]) and across three life stages (prebreeding adults, breeding adults, and chicks) in San Francisco Bay, California, USA. Across species and life stages, Hg concentrations (least square mean +/- standard error) were highest in head feathers (6.45 +/- 0.31 microg/g dry wt) and breast feathers (5.76 +/- 0.28 microg/g dry wt), followed by kidney (4.54 +/- 0.22 microg/g dry wt), liver (4.43 +/- 0.21 microg/g dry wt), blood (3.10 +/- 0.15 microg/g dry wt), and muscle (1.67 +/- 0.08 microg/g dry wt). Relative Hg distribution among tissues, however, differed by species and life stage. Mercury concentrations were highly correlated among internal tissues (r2 > or = 0.89). Conversely, the relationships between Hg in feathers and internal tissues were substantially weaker (r2 < or = 0.42). Regression slopes sometimes differed among species and life stages, indicating that care must be used when predicting Hg concentrations in one tissue based on those in another. However, we found good agreement between predictions made using a general tissue-prediction equation and more specific equations developed for each species and life stage. Finally, our results suggest that blood is an excellent, nonlethal predictor of Hg concentrations in internal tissues but that feathers are relatively poor indicators of Hg concentrations in internal tissues. PMID:18444697

  6. USA

    DEFF Research Database (Denmark)

    Nedergaard, Peter

    http://www.systime.dk/ungdomsuddannelser/almen-studieforberedelse/usa-en-grundbog-i-politik-og-okonomi.html......http://www.systime.dk/ungdomsuddannelser/almen-studieforberedelse/usa-en-grundbog-i-politik-og-okonomi.html...

  7. Evidence for natural molecular hydrogen seepage associated with Carolina bays (surficial, ovoid depressions on the Atlantic Coastal Plain, Province of the USA)

    Science.gov (United States)

    Zgonnik, Viacheslav; Beaumont, Valérie; Deville, Eric; Larin, Nikolay; Pillot, Daniel; Farrell, Kathleen M.

    2015-12-01

    A study of soil gases was made in North Carolina (USA) in and around morphological depressions called "Carolina bays." This type of depression is observed over the Atlantic coastal plains of the USA, but their origin remains debated. Significant concentrations of molecular hydrogen (H2) were detected, notably around the bays. These measurements suggest that Carolina bays are the surficial expression of fluid flow pathways for hydrogen gas moving from depth to the surface. The potential mechanisms of H2 production and transport and the geological controls on the fluid migration pathways are discussed, with reference to the hypothesis that Carolina bays are the result of local collapses caused by the alteration of rock along the deep pathways of H2 migrating towards the surface. The present H2 seepages are comparable to those in similar structures previously observed in the East European craton.

  8. ABUNDANCE AND DISTRIBUTION OF INDIGENOUS, NONINDIGENOUS, AND CRYPTOGENIC BENTHIC MACROFAUNA IN WILLAPA BAY, WASHINGTON, USA

    Science.gov (United States)

    Benthic macrofaunal samples were collected in Willapa Bay, WA, in four habitats [eelgrass (Zostera marina), Atlantic cordgrass (Spartina alterniflora), mud shrimp (Upogebia pugettensis), ghost shrimp (Neotrypaea californiensis)] in 1996 and in seven habitats (Zostera, Spartina, U...

  9. Guide to the littoral zone vascular flora of Carolina bay lakes (U.S.A.)

    Science.gov (United States)

    Howell, Nathan; Braham, Richard R

    2016-01-01

    Abstract Background Carolina bays are elliptic, directionally aligned basins of disputed origin that occur on the Atlantic Coastal Plain from the Delmarva Peninsula to southern Georgia. In southeastern North Carolina, several large, natural, lacustrine systems (i.e., Carolina bay lakes) exist within the geomorphological features known as Carolina bays. Within the current distribution of Carolina bays, Bladen and Columbus counties (North Carolina) contain the only known examples of Carolina bay lakes. The Carolina bay lakes can be split into two major divisions, the “Bladen Lakes Group” which is characterized as being relatively unproductive (dystrophic – oligotrophic), and Lake Waccamaw, which stands alone in Columbus County and is known for its high productivity and species richness. Although there have been several studies conducted on these unique lentic systems, none have documented the flora comprehensively. New information Over the 2013−2014 growing seasons, the littoral zone flora of Carolina bay lakes was surveyed and vouchered. Literature reviews and herbarium crawls complemented this fieldwork to produce an inventory of the vascular plant species. This survey detected 205 taxa (species/subspecies and varieties) in 136 genera and 80 vascular plant families. Thirty-one species (15.2%) are of conservation concern. Lake Waccamaw exhibited the highest species richness with 145 catalogued taxa and 26 species of conservation concern. Across all sites, the Cyperaceae (25 spp.), Poaceae (21 spp.), Asteraceae (13 spp.), Ericaceae (8 spp.), Juncaceae (8 spp.), and Lentibulariaceae (6 spp.) were the six most species-rich vascular plant families encountered. A guide to the littoral zone flora of Carolina bay lakes is presented herein, including dichotomous keys, species accounts (including abundance, habitat, phenology, and exsiccatae), as well as images of living species and vouchered specimens. PMID:27350764

  10. Perfluoroalkyl compounds in relation to life-history and reproductive parameters in bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, Florida, USA

    NARCIS (Netherlands)

    Houde, M.; Balmer, B.C.; Brandsma, S.H.; Wells, R.S.; Rowles, T.K.; Solomon, K.R.; Muir, D.C.G.

    2006-01-01

    Perfluoroalkyl compounds (PFCs) were determined in plasma, milk, and urine of free-ranging bottlenose dolphins (Tursiops truncatus) from Sarasota Bay (FL, USA) during three winter and two summer capture-and-release programs (2002¿ 2005). Plasma and urine samples were extracted using an ion-pairing m

  11. Application of the Hyperspectral Imager for the Coastal Ocean to Phytoplankton Ecology Studies in Monterey Bay, CA, USA

    Directory of Open Access Journals (Sweden)

    John P. Ryan

    2014-01-01

    Full Text Available As a demonstrator for technologies for the next generation of ocean color sensors, the Hyperspectral Imager for the Coastal Ocean (HICO provides enhanced spatial and spectral resolution that is required to understand optically complex aquatic environments. In this study we apply HICO, along with satellite remote sensing and in situ observations, to studies of phytoplankton ecology in a dynamic coastal upwelling environment—Monterey Bay, CA, USA. From a spring 2011 study, we examine HICO-detected spatial patterns in phytoplankton optical properties along an environmental gradient defined by upwelling flow patterns and along a temporal gradient of upwelling intensification. From a fall 2011 study, we use HICO’s enhanced spatial and spectral resolution to distinguish a small-scale “red tide” bloom, and we examine bloom expansion and its supporting processes using other remote sensing and in situ data. From a spectacular HICO image of the Monterey Bay region acquired during fall of 2012, we present a suite of algorithm results for characterization of phytoplankton, and we examine the strengths, limitations, and distinctions of each algorithm in the context of the enhanced spatial and spectral resolution.

  12. Improving lakebed sediment quality in an urban estuary, Presque Isle Bay, Lake Erie, USA

    Science.gov (United States)

    Foyle, A. M.; Norton, K. P.

    2007-12-01

    Presque Isle Bay, Lake Erie, is a microtidal freshwater estuary on the North American Great Lakes. It is one of 40 remaining environmental Areas of Concern (AoCs) on the Great Lakes that have one or more water, habitat, or sediment quality impairments as defined by the International Joint Commission. In-situ natural capping using sediment from to-be-remediated watersheds and other sources is being considered as the most feasible means of remediating contaminated sediments in the estuary. A multi-decade sediment budget shows that, when localized anthropogenic effects are accounted for, the estuary net-accumulated sediment over time from three major sources: the Lake Erie littoral system (20%), streams (25%), and bank erosion and bluff recession (41%). The non-stream sources supply environmentally clean sediment from ancient coastal deposits along the shoreline, and from the modern littoral system. However, organic and metallic contaminants are supplied by streams and run-off and remain a remediation challenge. From a geological perspective, natural capping of contaminated sediment over the next several decades is a viable solution for the majority of the bay. The mechanism may not work effectively in all areas because approximately 25% of the bay floor is moderately net- erosional or accumulates sediments very slowly.

  13. Postimpact heat conduction and compaction-driven fluid flow in the Chesapeake Bay impact structure based on downhole vitrinite reflectance data, ICDP-USGS Eyreville deep core holes and Cape Charles test holes

    Science.gov (United States)

    Malinconico, M.L.; Sanford, W.E.; Wright, Horton W.J.J., Jr.

    2009-01-01

    Vitrinite reflectance data from the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville deep cores in the centralcrater moat of the Chesapeake Bay impact structure and the Cape Charles test holes on the central uplift show patterns of postimpact maximum-temperature distribution that result from a combination of conductive and advective heat flow. Within the crater-fill sediment-clast breccia sequence at Eyreville, an isoreflectance (-0.44% Ro) section (525-1096 m depth) is higher than modeled background coastal-plain maturity and shows a pattern typical of advective fluid flow. Below an intervening granite slab, a short interval of sediment-clast breccia (1371-1397 m) shows a sharp increase in reflectance (0.47%-0.91% Ro) caused by conductive heat from the underlying suevite (1397-1474 m). Refl ectance data in the uppermost suevite range from 1.2% to 2.1% Ro. However, heat conduction alone is not sufficient to affect the temperature of sediments more than 100 m above the suevite. Thermal modeling of the Eyreville suevite as a 390 ??C cooling sill-like hot rock layer supplemented by compaction- driven vertical fluid flow (0.046 m/a) of cooling suevitic fluids and deeper basement brines (120 ??C) upward through the sediment breccias closely reproduces the measured reflectance data. This scenario would also replace any marine water trapped in the crater fill with more saline brine, similar to that currently in the crater, and it would produce temperatures sufficient to kill microbes in sediment breccias within 450 m above the synimsuevite. A similar downhole maturity pattern is present in the sediment-clast breccia over the central uplift. High-reflectance (5%-9%) black shale and siltstone clasts in the suevite and sediment-clast breccia record a pre-impact (Paleozoic?) metamorphic event. Previously published maturity data in the annular trough indicate no thermal effect there from impact-related processes. ?? 2009 The

  14. An Alexandrium Spp. Cyst Record from Sequim Bay, Washington State, USA, and its Relation to Past Climate Variability(1).

    Science.gov (United States)

    Feifel, Kirsten M; Moore, Stephanie K; Horner, Rita A

    2012-06-01

    Since the 1970s, Puget Sound, Washington State, USA, has experienced an increase in detections of paralytic shellfish toxins (PSTs) in shellfish due to blooms of the harmful dinoflagellate Alexandrium. Natural patterns of climate variability, such as the Pacific Decadal Oscillation (PDO), and changes in local environmental factors, such as sea surface temperature (SST) and air temperature, have been linked to the observed increase in PSTs. However, the lack of observations of PSTs in shellfish prior to the 1950s has inhibited statistical assessments of longer-term trends in climate and environmental conditions on Alexandrium blooms. After a bloom, Alexandrium cells can enter a dormant cyst stage, which settles on the seafloor and then becomes entrained into the sedimentary record. In this study, we created a record of Alexandrium spp. cysts from a sediment core obtained from Sequim Bay, Puget Sound. Cyst abundances ranged from 0 to 400 cysts · cm(-3) and were detected down-core to a depth of 100 cm, indicating that Alexandrium has been present in Sequim Bay since at least the late 1800s. The cyst record allowed us to statistically examine relationships with available environmental parameters over the past century. Local air temperature and sea surface temperature were positively and significantly correlated with cyst abundances from the late 1800s to 2005; no significant relationship was found between PDO and cyst abundances. This finding suggests that local environmental variations more strongly influence Alexandrium population dynamics in Puget Sound when compared to large-scale changes. PMID:27011070

  15. Composition and fluxes of particulate organic matter in a temperate estuary (Winyah Bay, South Carolina, USA) under contrasting physical forcings

    Science.gov (United States)

    Goñi, Miguel A.; Voulgaris, George; Kim, Yong H.

    2009-11-01

    To understand the role that physical processes play on the biogeochemical cycles of estuaries, we conducted intense field studies of the turbidity maximum region within a partially mixed estuary (Winyah Bay, SC, USA) under contrasting conditions of river discharge, tides and wind. Water samples and hydrographic data were collected at different depths and locations along the main channel over several tidal cycles during several cruises to Winyah Bay. Tidal variations in current speed, salinity, total suspended solid concentrations were measured within each cruise and were consistent with estuarine circulation processes. Salinity and total suspended solid concentrations ranged from 0 to 32 and from 20 to over 500 mg L -1, respectively, with the highest salinity and total suspended solid values measured during periods of low river discharge. In fact, comparison of tidally averaged salinity and total suspended solid concentrations revealed marked differences among cruises that were negatively correlated to river discharge and SW wind speed. Moreover, significant contrasts in the chemical compositions of suspended particles were evident among periods of contrasting river discharge and wind regime. For example, the weight percent organic carbon content of suspended particles ranged from 1 to over 6% and displayed a positive correlation with river discharge. Similarly, both the molar carbon to nitrogen ratios (10 to 20 mol:mol) and stable carbon isotopic compositions (-25 to -29%) of the suspended organic matter varied significantly as a function of discharge and wind. Such trends indicate that in Winyah Bay low river discharge and steady SW winds promote resuspension of bed sediments from shallow regions of the estuary. These materials contain highly altered organic matter and their incorporation into the water column leads to the observed trends in suspended particle concentrations and compositions. Furthermore, these conditions result in net landward fluxes of salt

  16. Impacts of diverted freshwater on dissolved organic matter and microbial communities in Barataria Bay, Louisiana, U.S.A.

    Science.gov (United States)

    Bianchi, Thomas S; Cook, Robert L; Perdue, E Michael; Kolic, Paulina E; Green, Nelson; Zhang, Yaoling; Smith, Richard W; Kolker, Alexander S; Ameen, Alex; King, Gary; Ojwang, Loice M; Schneider, Caroline L; Normand, Anna E; Hetland, Robert

    2011-12-01

    Here we present results of an initial assessment of the impacts of a water diversion event on the concentrations and chemical composition of dissolved organic matter (DOM) and bacterioplankton community composition in Barataria Bay, Louisiana U.S.A, an important estuary within the Mississippi River Delta complex. Concentrations and spectral properties of DOM, as reflected by UV/visible absorbance and fluorescence, were strikingly similar at 26 sites sampled along transects near two western and two eastern areas of Barataria Bay in July and September 2010. In September 2010, dissolved organic carbon (DOC) was significantly higher (568.1-1043 μM C, x=755.6+/-117.7 μM C, n=14) than in July 2010 (249.1-577.1 μM C, x=383.7+/-98.31 μM C, n=14); conversely, Abs254 was consistently higher at every site in July (0.105-0.314) than in September (0.080-0.221), averaging 0.24±0.06 in July and 0.15±0.04 in September. Fluorescence data via the fluorescence index (FI450/500) revealed that only 30% (8 of 26) of the July samples had an FI450/500 above 1.36, compared to 96% (25 of 26) for the September samples. This indicates a more terrestrial origin for the July DOM. Bacterioplankton from eastern sites differed in composition from bacterioplankon in western sites in July. These differences appeared to result from reduced salinities caused by the freshwater diversion. Bacterioplankton communities in September differed from those in July, but no spatial structure was observed. Thus, the trends in bacterioplankton and DOM were likely due to changes in water masses (e.g., input of Mississippi River water in July and a return to estuarine waters in September). Discharge of water from the Davis Pond Freshwater Diversion (DPFD) through Barataria Bay may have partially mitigated some adverse effects of the oil spill, inasmuch as DOM is concerned. PMID:22000271

  17. Benthic macrofauna productivity enhancement by an artificial reef in Delaware Bay, USA

    Energy Technology Data Exchange (ETDEWEB)

    Steimle, F; Foster, Karen L.; Kropp, Roy K.; Conlin, B

    2002-10-15

    To understand the potential enhancement value of a habitat-loss mitigation reef in Delaware Bay, especially as a source of food for fishery resources, the secondary productivity of the reef epifauna and nearby sand infauna was estimated and compared. The mean production of natural sand infauna was estimated at between 215 and 249 kcal m(2) yr(-1), while that of the epifauna on the reef surfaces was between 3990 and 9555 kcal m(2) yr(-1). With the 36 m(2) footprint of a reef unit as a basis for comparison, the 407 m(2) of reef unit surface covering that footprint produced 1.62-3.89 X 10(6) kcal yr(-1) of epifauna compared with 7.74-8.96 X 10(3) kcal yr(-1) per footprint area for the adjacent sand infauna. There was, however, substantial annual variability in the productivity of the epifauna, based on the recruitment success of Mytilus edulis.

  18. An examination of the population dynamics of syngnathid fishes within Tampa Bay, Florida, USA

    Directory of Open Access Journals (Sweden)

    Heather D. MASONJONES, Emily ROSE, Lori Benson McRAE,Danielle L. DIXSON

    2010-02-01

    Full Text Available Seagrass ecosystems worldwide have been declining, leading to a decrease in associated fish populations, especially those with low mobility such as syngnathids (pipefish and seahorses. This two-year pilot study investigated seasonal patterns in density, growth, site fidelity, and population dynamics of Tampa Bay (FL syngnathid fishes at a site adjacent to two marinas under construction. Using a modified mark-recapture technique, fish were collected periodically from three closely located sites that varied in seagrass species (Thalassia spp., Syringodium spp., and mixed-grass sites and their distance from open water, but had consistent physical/chemical environmental characteristics. Fish were marked, photographed for body size and gender measurements, and released the same day at the capture site. Of the 5695 individuals surveyed, 49 individuals were recaptured, indicating a large, flexible population. Population density peaks were observed in July of both years, with low densities in late winter and late summer. Spatially, syngnathid densities were highest closest to the mouth of the bay and lowest near the shoreline. Seven species of syngnathid fishes were observed, and species-specific patterns of seagrass use emerged during the study. However, only two species, Syngnathus scovelli and Hippocampus zosterae, were observed at high frequencies. For these two species, body size decreased across the study period, but while S. scovelli’s population density decreased, H. zosterae’s increased. Across six of the seven species, population size declined over the course of this preliminary study; however, seasonal shifts were impossible to distinguish from potential anthropogenic effects of construction [Current Zoology 56 (1: 118–133, 2010].

  19. Helium systematics of cold seep fluids at Monterey Bay, California, USA: Temporal variations and mantle contributions

    Science.gov (United States)

    Füri, E.; Hilton, D. R.; Brown, K. M.; Tryon, M. D.

    2009-08-01

    We report helium isotope ratios (3He/4He) as well as helium and neon abundance results for submarine cold seep fluids from Extrovert Cliff in Monterey Bay, California. Samples were collected in copper tubing attached to submarine flux meters operating in continuous pumping mode. Following instrumentation recovery, the tubing was sectioned to produce for the first time a high-resolution time series of dissolved He and Ne variations over a time span of several days. Noble gas concentrations are variable and appear affected by interaction with a hydrocarbon phase within the aquifer. However, it is still possible to resolve the He signal into components associated with air equilibration, excess air entrainment, and terrigenic fluxes (both crustal and mantle-derived). The mantle He contribution reaches ˜25-30% in some samples (up to 2.3 RA, where RA = air 3He/4He). Our quasi-continuous He-Ne record shows remarkable fluctuations over time scales of only a few hours and reflects the combined effects of gas stripping by hydrocarbons and an episodic input of mantle-derived fluids.

  20. Antibodies to Influenza A Viruses in Gulls at Delaware Bay, USA.

    Science.gov (United States)

    Guinn, Kayla; Fojtik, Alinde; Davis-Fields, Nick; Poulson, Rebecca L; Krauss, Scott; Webster, Robert G; Stallknecht, David E

    2016-05-01

    Gulls are the known reservoir for H13 and H16 influenza A viruses (IAV) but also host a diversity of other IAV subtypes. Gulls also share habitats with both ducks and shorebirds, increasing the potential for cross-species IAV transmission. We serologically tested laughing gulls (Leucophaeus atricilla) collected at Delaware Bay during May when they were in direct contact with IAV-infected shorebirds; both species feed on horseshoe crab (Limulus polyphemus) eggs on beaches during this month. From 2010 to 2014, antibody prevalence as determined by competitive blocking enzyme-linked immunosorbent assay ranged from 25%-72%. Antibodies to H13 and H16 were detected by hemagglutination inhibition (HI) tests in 12% and 24% of tested gulls, respectively. Results from virus microneutralization (MN) tests for antibodies to H1-H12, H14, and H15 varied among years but the highest prevalence of neutralizing antibodies was detected against H1 (24%), H5 (25%), H6 (35%), H9 (33%), and H11 (42%) IAV. The subtype diversity identified by serology in gulls was dominated by Group 1 HA subtypes and only partially reflected the diversity of IAV subtypes isolated from shorebirds. PMID:27309077

  1. Some challenges of an "upside down" nitrogen budget--science and management in Greenwich Bay, RI (USA).

    Science.gov (United States)

    DiMilla, Peter A; Nixon, Scott W; Oczkowski, Autumn J; Altabet, Mark A; McKinney, Richard A

    2011-04-01

    When nutrients impact estuarine water quality, scientists and managers instinctively focus on quantifying and controlling land-based sources. However, in Greenwich Bay, RI, the estuary opens onto a larger and more intensively fertilized coastal water body (Narragansett Bay). Previous inventories of nitrogen (N) inputs to Greenwich Bay found that N inputs from Narragansett Bay exceeded those from the local watershed, suggesting that recent efforts to reduce local watershed N loads may have little effect on estuarine water quality. We used stable isotopes of N to characterize watershed and Narragansett Bay N sources as well as the composition of primary producers and consumers throughout Greenwich Bay. Results were consistent with previous assessments of the importance of N inputs to Greenwich Bay from Narragansett Bay. As multiple N sources contribute to estuarine water quality, effective management requires attention to individual sources commensurate with overall magnitude, regardless of the political complications that may entail. PMID:21353254

  2. 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 that 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 and wildlife communities, and the inundation duration and depth of the marsh platform. The objective of this research was to evaluate how 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 in 2010 and 2011, 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 tidal marshes and how that may affect the hydrogeomorphic processes and marsh biotic communities. This type of information is useful to managers for incorporating local climate change into developing their monitoring, management, and adaptation strategies.

  3. Chesapeake Bay Hypoxic Volume Forecasts and Results

    Science.gov (United States)

    Evans, Mary Anne; Scavia, Donald

    2013-01-01

    Given the average Jan-May 2013 total nitrogen load of 162,028 kg/day, this summer's hypoxia volume forecast is 6.1 km3, slightly smaller than average size for the period of record and almost the same as 2012. The late July 2013 measured volume was 6.92 km3.

  4. CHESAPEAKE BAY 2007 RE-EVALUATION

    Science.gov (United States)

    A long term goal of multimedia environmental management is to achieve sustainable ecological resources. Progress towards this goal rests on a foundation of science-based methods and data integrated into predictive multimedia, multi-stressor open architecture modeling systems. The...

  5. BASEMAP, CITY OF CHESAPEAKE, VIRGINIA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — FEMA Framework Basemap datasets comprise six of the seven FGDC themes of geospatial data that are used by most GIS applications (Note: the seventh framework theme,...

  6. Spatiotemporal variations in the abundance and composition of bulk and chromophoric dissolved organic matter in seasonally hypoxia-influenced Green Bay, Lake Michigan, USA.

    Science.gov (United States)

    DeVilbiss, Stephen E; Zhou, Zhengzhen; Klump, J Val; Guo, Laodong

    2016-09-15

    Green Bay, Lake Michigan, USA, is the largest freshwater estuary in the Laurentian Great Lakes and receives disproportional terrestrial inputs as a result of a high watershed to bay surface area ratio. While seasonal hypoxia and the formation of "dead zones" in Green Bay have received increasing attention, there are no systematic studies on the dynamics of dissolved organic matter (DOM) and its linkage to the development of hypoxia. During summer 2014, bulk dissolved organic carbon (DOC) analysis, UV-vis spectroscopy, and fluorescence excitation-emission matrices (EEMs) coupled with PARAFAC analysis were used to quantify the abundance, composition and source of DOM and their spatiotemporal variations in Green Bay, Lake Michigan. Concentrations of DOC ranged from 202 to 571μM-C (average=361±73μM-C) in June and from 279 to 610μM-C (average=349±64μM-C) in August. In both months, absorption coefficient at 254nm (a254) was strongly correlated to bulk DOC and was most abundant in the Fox River, attesting a dominant terrestrial input. Non-chromophoric DOC comprised, on average, ~32% of bulk DOC in June with higher terrestrial DOM and ~47% in August with higher aquagenic DOM, indicating that autochthonous and more degraded DOM is of lower optical activity. PARAFAC modeling on EEM data resulted in four major fluorescent DOM components, including two terrestrial humic-like, one aquagenic humic-like, and one protein-like component. Variations in the abundance of DOM components further supported changes in DOM sources. Mixing behavior of DOM components also indicated that while bulk DOM behaved quasi-conservatively, significant compositional changes occurred during transport from the Fox River to the open bay. PMID:27243792

  7. Heavy metal contamination from historic mining in upland soil and estuarine sediments of Egypt Bay, Maine, USA

    Science.gov (United States)

    Osher, L. J.; Leclerc, L.; Wiersma, G. B.; Hess, C. T.; Guiseppe, V. E.

    2006-10-01

    Concentrations of Cd, Cu, Pb and Zn in sediments of Egypt Bay in Hancock County, Maine, are elevated above background levels. The source of the contamination is Cu mining that occurred in the uplands adjacent to Egypt Stream between 1877 and 1885. Egypt Stream is a tributary to Egypt Bay. Egypt Bay is part of the Taunton Bay estuary system. The Hagan Mine was one of the mines extracting metals from the sulfide deposits in Downeast Maine north of Penobscot Bay. Metal concentrations were determined using ICP-AES after sample digestion with nitric acid. Soil collected from the coarse textured mine tailings pile contained elevated concentrations of Cd, Cu, Pb and Zn, but the majority of the surface soils at the Hagan Mine site were not contaminated. Estuary sediments from the surface to 100 cm depth were collected in four locations within Egypt Bay. Below 40 cm, metal concentrations in sediments were similar to those in uncontaminated upland soils. Metal concentrations in the estuary sediments between the surface and 26 cm were above background levels. According to 210Pb dating, the sediment at 26-34 cm depth was likely to have been deposited at the time the historic mines were in operation. Concentrations of Cd, Cu, Pb, and Zn in sediment from the 32-34 cm depth interval are similar to concentrations in the upland soil sample from the mine tailings pile. Elevated Pb concentrations in sediments from the surface to 24 cm are from atmospheric Pb deposition from anthropogenic sources. Sediment in the top 10 cm of the estuary has been mixed both by the polychaete worm Nereis virens and by those harvesting the worms for sale as fish bait.

  8. Evaluating nonindigenous species management in a Bayesian networks derived relative risk framework for Padilla Bay, WA, USA.

    Science.gov (United States)

    Herring, Carlie E; Stinson, Jonah; Landis, Wayne G

    2015-10-01

    Many coastal regions are encountering issues with the spread of nonindigenous species (NIS). In this study, we conducted a regional risk assessment using a Bayesian network relative risk model (BN-RRM) to analyze multiple vectors of NIS introductions to Padilla Bay, Washington, a National Estuarine Research Reserve. We had 3 objectives in this study. The 1st objective was to determine whether the BN-RRM could be used to calculate risk from NIS introductions for Padilla Bay. Our 2nd objective was to determine which regions and endpoints were at greatest risk from NIS introductions. Our 3rd objective was to incorporate a management option into the model and predict endpoint risk if it were to be implemented. Eradication can occur at different stages of NIS invasions, such as the elimination of these species before being introduced to the habitat or removal of the species after settlement. We incorporated the ballast water treatment management scenario into the model, observed the risk to the endpoints, and compared this risk with the initial risk estimates. The model results indicated that the southern portion of the bay was at greatest risk because of NIS. Changes in community composition, Dungeness crab, and eelgrass were the endpoints most at risk from NIS introductions. The currents node, which controls the exposure of NIS to the bay from the surrounding marine environment, was the parameter that had the greatest influence on risk. The ballast water management scenario displayed an approximate 1% reduction in risk in this Padilla Bay case study. The models we developed provide an adaptable template for decision makers interested in managing NIS in other coastal regions and large bodies of water. PMID:25845995

  9. Comparing sediment equilibrium partitioning and passive sampling techniques to estimate benthic biota PCDD/F concentrations in Newark Bay, New Jersey (U.S.A.)

    International Nuclear Information System (INIS)

    Sediment and polyethylene sampler-based estimates of polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/F) concentrations in Newark Bay, New Jersey (USA) benthic biota were compared. Biota concentrations based on sediment were estimated using an organic carbon (OC)-water partitioning model and an OC and black carbon (BC)-water dual model. Biota concentrations based on polyethylene were estimated from samplers deployed in the Newark Bay water column and samplers immersed in a sediment/porewater slurry in the laboratory. Porewater samplers provided the best estimates of biota concentrations (within 3.1×), with best results achieved for deposit-feeders (within 1.6×). Polyethylene deployed in deep water also provided good estimates of biota concentrations (within 4×). By contrast, OC-water partitioning overestimated biota concentrations by up to 7×, while OC and BC combined underestimated biota concentrations by up to 13×. We recommend passive samplers such as polyethylene for estimating concentrations of hydrophobic organic contaminants in field biota given its simplicity and relatively lower uncertainty compared to sediment equilibrium partitioning. -- Highlights: • PE samplers accurately estimate Newark Bay biota PCDD/F concentrations. • A traditional KOC partitioning model overestimated PCDD/F uptake by a factor of 4–7. • A dual KOC and KBC model underestimated biota PCDD/F uptake by a factor of 4–13. • Sediment- and depth-specific KBCs improved predictions of PCDD/F uptake. • Deposit feeder uptake switches from porewater control to ingestion at log KOW 6–7. -- Using polyethylene samplers to measure porewater concentrations is a more efficient approach for estimating site-specific bioavailable organic contaminants than equilibrium partitioning

  10. Mercury burdens in Chinese mitten crabs (Eriocheir sinensis) in three tributaries of southern San Francisco Bay, California, USA

    International Nuclear Information System (INIS)

    Chinese mitten crabs (Eriocheir sinensis), endemic to Asia, were first reported in the San Francisco Bay in 1992. They are now established in nearly all San Francisco Bay tributaries. These crabs accumulate more metals, such as mercury, than crustaceans living in the water column. Because their predators include fish, birds, mammals and humans, their mercury burdens have an exceptional potential to impact the ecosystem and public health. We sought to elucidate the potential threat of mitten crab mercury burdens in three adjacent streams in southern San Francisco Bay, one of which is known to be contaminated with mercury. Mitten crabs had hepatopancreas concentrations of total mercury and methylmercury that did not differ among streams. The maximum burden we measured was below the action level of 1 ppm recommended by the USEPA. Hepatopancreas concentrations of methylmercury declined with increasing crab size, suggesting a mechanism for mercury excretion and that predators might reduce mercury exposure if they select larger crabs. Because mercury may be heterogeneously distributed among tissues, estimation of the impacts of crab mercury burdens on the environment requires more data on the feeding preferences of predators. - Hepatopancreas concentrations of mercury decline with crab size, which may have important consequences for bio-magnification in food webs

  11. Impact of Late Holocene climate variability and anthropogenic activities on Biscayne Bay (Florida, U.S.A.): evidence from diatoms

    Science.gov (United States)

    Wachnicka, Anna; Gaiser, Evelyn; Wingard, Lynn; Briceño, Henry; Harlem, Peter

    2013-01-01

    Shallow marine ecosystems are experiencing significant environmental alterations as a result of changing climate and increasing human activities along coasts. Intensive urbanization of the southeast Florida coast and intensification of climate change over the last few centuries changed the character of coastal ecosystems in the semi-enclosed Biscayne Bay, Florida. In order to develop management policies for the Bay, it is vital to obtain reliable scientific evidence of past ecological conditions. The long-term records of subfossil diatoms obtained from No Name Bank and Featherbed Bank in the Central Biscayne Bay, and from the Card Sound Bank in the neighboring Card Sound, were used to study the magnitude of the environmental change caused by climate variability and water management over the last ~ 600 yr. Analyses of these records revealed that the major shifts in the diatom assemblage structures at No Name Bank occurred in 1956, at Featherbed Bank in 1966, and at Card Sound Bank in 1957. Smaller magnitude shifts were also recorded at Featherbed Bank in 1893, 1942, 1974 and 1983. Most of these changes coincided with severe drought periods that developed during the cold phases of El Niño Southern Oscillation (ENSO), Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO), or when AMO was in warm phase and PDO was in the cold phase. Only the 1983 change coincided with an unusually wet period that developed during the warm phases of ENSO and PDO. Quantitative reconstructions of salinity using the weighted averaging partial least squares (WA-PLS) diatom-based salinity model revealed a gradual increase in salinity at the three coring locations over the last ~ 600 yr, which was primarily caused by continuously rising sea level and in the last several decades also by the reduction of the amount of freshwater inflow from the mainland. Concentration of sediment total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) increased in the

  12. A Case History of the Science and Management Collaboration in Understanding Hypoxia Events in Long Bay, South Carolina, USA

    Science.gov (United States)

    Sanger, Denise; Hernandez, Debra; Libes, Susan; Voulgaris, George; Davis, Braxton; Smith, Erik; Shuford, Rebecca; Porter, Dwayne; Koepfler, Eric; Bennett, Joseph

    2010-09-01

    Communication of knowledge between the scientific and management communities is a difficult process complicated by the distinctive nature of professional career goals of scientists and decision-makers. This article provides a case history highlighting a collaboration between the science and management communities that resulted from a response to a 2004 hypoxia, or low dissolved oxygen, event in Long Bay, off Myrtle Beach, South Carolina. A working group of scientists and decision-makers was established at the time of the event and has continued to interact to develop a firm understanding of the drivers responsible for hypoxia formation in Long Bay. Several factors were found to be important to ensure that these collaborative efforts were productive: (1) genuine interest in collaboratively working across disciplines to examine a problem; (2) commitment by agency leadership, decision-makers, and researchers to create successful communication mechanisms; (3) respect for each others’ perspectives and an understanding how science and management are performed and that they are not mutually exclusive; (4) networking among researchers and decision-makers to ensure appropriate team members are involved in the process; (5) use of decision-maker input in the formulation of research and monitoring projects; and (6) commitment of resources for facilitation to ensure that researchers and decision-makers are communicating effectively.

  13. An evaluation of the success of dredging as remediation at a DDT-contaminated site in San Francisco Bay, California, USA.

    Science.gov (United States)

    Weston, Donald P; Jarman, Walter M; Cabana, Gilbert; Bacon, Corinne E; Jacobson, Lisa A

    2002-10-01

    Lauritzen Canal, a portion of San Francisco Bay near Richmond, California, USA, was heavily contaminated with dichlorodiphenyltrichloroethane (DDT) and dieldrin as a result of releases from a pesticide-formulating firm. In 1996 and 1997, 82,000 m3 of contaminated sediment was removed from the canal by dredging. This study evaluated the success of the dredging based largely on body burdens of DDT and its metabolites (sigmaDDT) in resident biota, with some data on sediment- and water-contaminant levels and sediment toxicity testing. Sediment disturbance during dredging introduced a pulse of sigmaDDT into the Lauritzen Canal ecosystem, and body burdens of fish and invertebrates increased 2- to 76-fold, depending on the species. Approximately 1 1/2 years after remediation, 11 of 14 indicators showed contamination comparable with or worse than the contamination that existed prior to dredging. Monitoring of mussels up to four years postdredging suggests some modest improvement, although the sigmaDDT body burden of canal mussels remained far above the norm for San Francisco Bay. The elevated sigmaDDT body burdens in biota that persisted for years after remediation reflect recent exposure and are not merely a result of slow metabolic elimination of the sigmaDDT pulse associated with dredging. Sediment sigmaDDT concentrations were low immediately after dredging, but within months, the canal bottom became covered with a veneer of fine sediment as contaminated as that that had been removed. The source of this material has not been conclusively established, but we suspect it came from slumping and erosion from the flanks of the canal beneath docks and around pilings where dredging was not done. In retrospect, either capping in place or more thorough dredging may have been more successful in reducing pesticide exposure of the biota, although there were difficulties associated with both alternatives. PMID:12371501

  14. Serum Biomarkers of Polyfluoroalkyl Compound Exposure in Young Girls in Greater Cincinnati and the San Francisco Bay Area, USA

    OpenAIRE

    Pinney, Susan M.; Biro, Frank M; Windham, Gayle; Herrick, Robert L.; Yaghjyan, Lusine; Calafat, Antonia M.; Succop, Paul; Sucharew, Heidi; Ball, Kathleen M.; Kato, Kayoko; Kushi, Lawrence H.; Bornschein, Robert

    2013-01-01

    PFC serum concentrations were measured in 6–8 year-old girls in Greater Cincinnati (GC) (N=353) and the San Francisco Bay Area (SFBA) (N=351). PFOA median concentration was lower in the SFBA than GC (5.8 vs. 7.3 ng/mL). In GC, 48/51 girls living in one area had PFOA concentrations above the NHANES 95th percentile for children 12–19 years (8.4 ng/mL), median 22.0 ng/mL. The duration of being breast fed was associated with higher serum PFOA at both sites and with higher PFOS, PFHxS and Me-PFOSA...

  15. Serum biomarkers of polyfluoroalkyl compound exposure in young girls in Greater Cincinnati and the San Francisco Bay Area, USA

    International Nuclear Information System (INIS)

    PFC serum concentrations were measured in 6–8 year-old girls in Greater Cincinnati (GC) (N = 353) and the San Francisco Bay Area (SFBA) (N = 351). PFOA median concentration was lower in the SFBA than GC (5.8 vs. 7.3 ng/mL). In GC, 48/51 girls living in one area had PFOA concentrations above the NHANES 95th percentile for children 12–19 years (8.4 ng/mL), median 22.0 ng/mL. The duration of being breast fed was associated with higher serum PFOA at both sites and with higher PFOS, PFHxS and Me-PFOSA-AcOH concentrations in GC. Correlations of the PFC analytes with each other suggest that a source upriver from GC may have contributed to exposures through drinking water, and water treatment with granular activated carbon filtration resulted in less exposure for SWO girls compared to those in NKY. PFOA has been characterized as a drinking water contaminant, and water treatment systems effective in removing PFCs will reduce body burdens. -- Highlights: • PFC serum concentrations were measured in 6–8 year-old girls. • Study sites in Greater Cincinnati (N = 353) and the San Francisco Bay Area (N = 351). • The duration of being breast fed was associated with higher serum PFOA. • Lower PFOA in girls living in areas with granular activated carbon water treatment. -- Serum concentrations of PFCs in young girls were higher in girls who had been breast fed longer, and lower in girls in areas with granular activated carbon municipal water treatment

  16. Perfluoroalkyl compounds in relation to life-history and reproductive parameters in bottlenose dolphins (Tursiops truncatus) from Sarasota Bay, Florida, U.S.A.

    Science.gov (United States)

    Houde, Magali; Balmer, Brian C; Brandsma, Sicco; Wells, Randall S; Rowles, Teri K; Solomon, Keith R; Muir, Derek C G

    2006-09-01

    Perfluoroalkyl compounds (PFCs) were determined in plasma, milk, and urine of free-ranging bottlenose dolphins (Tursiops truncatus) from Sarasota Bay (FL, USA) during three winter and two summer capture-and-release programs (2002-2005). Plasma and urine samples were extracted using an ion-pairing method. Perfluoroalkyl compounds were extracted from milk samples using acetonitrile, and extracts were cleaned with graphitized nonporous carbon. All extracts were analyzed by high-performance liquid chromatography-tandem mass spectrometry. Mean seasonal sum of PFCs (sigma PFCs) detected in dolphin plasma ranged from 530 to 927 ng/g wet weight. No significant differences (p > 0.05) were found in concentrations between seasons, suggesting a constant exposure to PFCs. Overall, blubber thickness of dolphins did not correlate with PFC concentrations in plasma, suggesting an absence of PFC sequestration in blubber. Sexually immature calves (age, dolphins. Results from the present study showed that young and developing bottlenose dolphins are highly exposed to PFCs. These chemicals also were detected in urine (mean sigma PFCs, 26.6 +/- 79 ng/g wet wt), indicating that the urinary system is an important pathway of PFC depuration in dolphins. PMID:16986796

  17. Natural radionuclides 210Po and 210Pb in the Delaware and Chesapeake Estuaries: modeling scavenging rates and residence times

    International Nuclear Information System (INIS)

    During the spring and summer months of 2012, 210Po and 210Pb activity were measured in the dissolved and particulate phases from the Delaware and upper Chesapeake estuaries. The upper Delaware estuary, near the freshwater end member, was characterized by high-suspended matter concentrations that scavenged dissolved 210Po and 210Pb. Box models were applied using mass balance calculations to assess the nuclides residence times in each estuary. Only 60% of the dissolved 210Po and 55% of the dissolved 210Pb from the Delaware estuary were exported to coastal waters. A large fraction of soluble 210Po and 210Pb within the estuary was either reversibly adsorbed onto suspended particles, trapped in sediment accumulation zones (such as intertidal marshes), bioaccumulated into phytoplankton and discharged to the coastal ocean. The upper Chesapeake estuary was largely characterized by sub-oxic bottom waters that contained higher concentrations of dissolved 210Po and 210Pb, hypothesized to be subjected to redox cycling of manganese. The Delaware and Chesapeake estuary mean residence times for 210Po differed significantly at 86 ± 7 and 126 ± 10 days respectively, while they were similar for 210Pb (67 ± 6–55 ± 5 days). The difference in residence times corresponds to the greater extent of biogeochemical scavenging and regeneration processes within the upper Chesapeake. - Highlights: • Estuarine 210Pb and 210Po data reveal key biogeochemical processes and rates. • Delaware Bay displays regional differentiation due to dominant particle reactions. •Chesapeake Bay displays vertical differentiation from deep sub-oxic redox cycling. • Parent (210Pb) grand-daughter (210Po) disequilibria evidence principle processes. • Net scavenging residence times calculated weeks (Delaware) to months (Chesapeake)

  18. Changes in production and respiration during a spring phytoplankton bloom in San Francisco Bay, California, USA: Implications for net ecosystem metabolism

    Science.gov (United States)

    Caffrey, J.M.; Cloern, J.E.; Grenz, C.

    1998-01-01

    We present results of an intensive sampling program designed to measure weekly changes in ecosystem respiration (oxygen consumption in the water column and sediments) around the 1996 spring bloom in South San Francisco Bay, California, USA. Measurements were made at a shallow site (2 m, where mean photic depth was 60% of the water column height) and a deep site (15 m, mean photic depth was only 20% of the water column). We also estimated phytoplankton primary production weekly at both sites to develop estimates of net oxygen flux as the sum of pelagic production (PP), pelagic respiration (PR) and benthic respiration (BR). Over the 14 wk period from February 5 to May 14, PP ranged from 2 to 210, PR from 9 to 289, and BR from 0.1 to 48 mmol O2 m-2 d-1, illustrating large variability of estuarine oxygen fluxes at the weekly time scale. Pelagic production exceeded total respiration at the shallow site, but not at the deep site, demonstrating that the shallow domains are net autotrophic but the deep domains are net heterotrophic, even during the period of the spring bloom. If we take into account the potential primary production by benthic microalgae, the estuary as a whole is net autotrophic during spring, net heterotrophic during the nonbloom seasons, and has a balanced net metabolism over a full annual period. The seasonal shift from net autotrophy to heterotrophy during the transition from spring to summer was accompanied by a large shift from dominance by pelagic respiration to dominance by benthic respiration. This suggests that changes in net ecosystem metabolism can reflect changes in the pathways of energy flow in shallow coastal ecosystems.

  19. Tidal Marsh Stratigraphy, Sea-Level Change and Large EARTHQUAKES—II: Submergence Events during the Last 3500 Years at Netarts Bay, Oregon, USA

    Science.gov (United States)

    Shennan, I.; Long, A. J.; Rutherford, M. M.; Innes, J. B.; Green, F. M.; Walker, K. J.

    This is the second investigation where we apply the methods and scientific framework common to sea-level investigations in northwest Europe to test a model of coseismic land subsidence followed by land uplift during interseismic strain accumulation, used to explain alternating peat-mud couplets of late Holocene age found in many of the estuaries of the Pacific Northwest of the USA and Canada. Recent studies in this region interpret such couplets as the product of repeated large (magnitude 8 or 9) earthquakes on the Cascadia subduction zone. Stratigraphic investigations of the intertidal sediments at Netarts Bay, Oregon, using lithological, pollen and diatom analyses reveal different types of submergence associated with peat-mud couplets during the last 3500 yr. Three peat-mud couplets record gradual sedimentation changes within an infilling body of water. Four other couplets record rapid submergence, burial of tidal marshes and their replacement by low marsh environments. In three of the events rapid submergence is small, 0-0.5 m. The most recent marsh submergence event, around AD 1700, was 0.4±0.3 m. Most of the buried peats contain microfossil evidence for a gradual increase in marine influence before the rapid change from organic to minerogenic sedimentation. Similar gradual changes are common in comparable palaeoenvironments on non-seismic coasts and are strong evidence against a simple interseismic strain accumulation-coseismic subsidence model. One hypothesis is that the gradual increase in marine influence before each submergence represents pre-seismic relative sea-level rise caused by a reduction in the rate of land uplift. The microfossil analyses provide evidence of three stages within an earthquake deformation cycle: coseismic subsidence; interseismic land uplift; and pre-seismic reduction in the rate of land uplift. At present the microfossil data do not differentiate between rapid post-seismic land uplift and rapid sedimentation.

  20. More than a century of bathymetric observations and present-day shallow sediment characterization in Belfast Bay, Maine, USA: Implications for pockmark field longevity

    Science.gov (United States)

    Brothers, L.L.; Kelley, J.T.; Belknap, D.F.; Barnhardt, W.A.; Andrews, B.D.; Maynard, M.L.

    2011-01-01

    Mechanisms and timescales responsible for pockmark formation and maintenance remain uncertain, especially in areas lacking extensive thermogenic fluid deposits (e.g., previously glaciated estuaries). This study characterizes seafloor activity in the Belfast Bay, Maine nearshore pockmark field using (1) three swath bathymetry datasets collected between 1999 and 2008, complemented by analyses of shallow box-core samples for radionuclide activity and undrained shear strength, and (2) historical bathymetric data (report and smooth sheets from 1872, 1947, 1948). In addition, because repeat swath bathymetry surveys are an emerging data source, we present a selected literature review of recent studies using such datasets for seafloor change analysis. This study is the first to apply the method to a pockmark field, and characterizes macro-scale (>5 m) evolution of tens of square kilometers of highly irregular seafloor. Presence/absence analysis yielded no change in pockmark frequency or distribution over a 9-year period (1999-2008). In that time pockmarks did not detectably enlarge, truncate, elongate, or combine. Historical data indicate that pockmark chains already existed in the 19th century. Despite the lack of macroscopic changes in the field, near-bed undrained shear-strength values of less than 7 kPa and scattered downcore 137Cs signatures indicate a highly disturbed setting. Integrating these findings with independent geophysical and geochemical observations made in the pockmark field, it can be concluded that (1) large-scale sediment resuspension and dispersion related to pockmark formation and failure do not occur frequently within this field, and (2) pockmarks can persevere in a dynamic estuarine setting that exhibits minimal modern fluid venting. Although pockmarks are conventionally thought to be long-lived features maintained by a combination of fluid venting and minimal sediment accumulation, this suggests that other mechanisms may be equally active in

  1. Organic composition of PM 2.5 and size-segregated aerosols and their sources during the 2002 Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA

    Science.gov (United States)

    Tremblay, Raphaël T.; Riemer, Daniel D.; Zika, Rod G.

    PM 2.5 and size-segregated aerosols were collected in May 2002 as part of the Bay Regional Atmospheric Chemistry Experiment (BRACE), Florida, USA. Aerosol organic composition was used to estimate sources of a series of alkanes and polycyclic aromatic hydrocarbons (PAHs) using chemical indices, hierarchical cluster analysis (HCA) and a chemical mass balance receptor model (CMB). Aerosols were collected on quartz fiber filters (QFF) using a PM 2.5 high volume sampler and on aluminum foil discs using a Micro-Orifice Uniform Deposit Impactor (MOUDI, 50% aerodynamic cut diameters were 18, 10, 5.6, 3.2, 1.8, 1.0, 0.56, 0.315 and 0.171 μm). Target compounds included alkanes and PAHs and were solvent extracted using a mixture of dichloromethane, acetone and hexane, concentrated and then analyzed using a gas chromatograph/mass spectrometer (GC/MS). The target compounds in PM 2.5 were dominated by six sources during the study period: mobile sources (39±5%), coal burning (33±5%), biogenic primary emission (20±2%), oil combustion (5±2%), biomass burning (1.0±0.3%) and an unidentified source (3±2%). Results obtained from the chemical indices, HCA and CMB were in very good agreement with each other. PAH size distributions are presented for days dominated by a same source. Seventy-five percent and 50% of the PAH were found below 1.8 and 0.56 μm, respectively (monthly PAH geometric diameters averaged 0.43 μm). Coarse size PAHs were observed on 1 day (15 May) and were correlated with nitrate and sodium size distribution. It is hypothesized that the PAHs, sodium and nitrate were internally mixed and that the PAHs deposited onto a pre-existing marine aerosol. This transfer process has significant implications for PAH deposition and lifetime and warrants further study.

  2. 33 CFR 165.556 - Regulated Navigation Area; Chesapeake and Delaware Canal, Chesapeake City Anchorage Basin, MD.

    Science.gov (United States)

    2010-07-01

    ... areas, found in 33 CFR 165.13, apply to the regulated navigation area described in paragraph (a) of this...; Chesapeake and Delaware Canal, Chesapeake City Anchorage Basin, MD. 165.556 Section 165.556 Navigation and..., Chesapeake City Anchorage Basin, MD. (a) Location. The following area is a regulated navigation area:...

  3. Chesapeake Bay Water Quality Monitoring Using Satellite Imagery Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Work done at Water Resources Center, University of Minnesota has demonstrated the feasibility of performing regional assessment of lake water quality using Landsat...

  4. Wetland Habitats for Wildlife of the Chesapeake Bay

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report reviews wildlife that use these three general wetland habitats; shallow water wetlands, forested wetlands and emergent wetlands. Wildlife discussed are...

  5. Ecological studies in the middle reach of Chesapeake Bay

    International Nuclear Information System (INIS)

    Passage of estuarine water and phytoplankton through the cooling system of the Calvert Cliffs nuclear power plant in the summer months of 1977-1981 resulted in frequent reductions of phytoplankton densities particularly during periods when flagellated taxa dominated total cell numbers. Entrainment-induced reductions in chlorophyll were observed on only four occasions, however. Phytoplankton productivity as oxygen evolution or 14C-uptake was even more susceptible to the effects of passing through the cooling system. Inhibition of productivitiy was observed during periods dominated by flagellated cells and generally occurred with ambient water temperature ≥ 250C. Results from track autoradiography employed in 1981 indicated that carbon fixation in the commonly observed flagellate Cryptomonas acuta was significantly depressed during July, August and September. In contrast, the dinoflagellate Prorocentrum minimum and the diatoms Cyclotella caspia and Thalassionema nitzschioides were not affected by entrainment. Although entrainment affects Cryptomonas and flagellate-dominated assemblages in the summer there are no detectable effects of power plant operations on cell densities or productivity in flagellate-dominated waters in the vicinity of the power plant. Transitory exposure of estuarine zooplankton to the elevated temperatures of CCNPP entrainment and discharge plumes was generally non-lethal. In the species selected for study the survival rate after entrainment was 65 to 100%. The effects of temperature, salinity and dissolved oxygen levels upon entrained organisms were also analyzed. (orig.)

  6. Comparative visual function in four piscivorous fishes inhabiting Chesapeake Bay.

    Science.gov (United States)

    Horodysky, Andrij Z; Brill, Richard W; Warrant, Eric J; Musick, John A; Latour, Robert J

    2010-05-01

    Maintaining optimal visual performance is a difficult task in photodynamic coastal and estuarine waters because of the unavoidable tradeoffs between luminous sensitivity and spatial and temporal resolution, yet the visual systems of coastal piscivores remain understudied despite differences in their ecomorphology and microhabitat use. We therefore used electroretinographic techniques to describe the light sensitivities, temporal properties and spectral sensitivities of the visual systems of four piscivorous fishes common to coastal and estuarine waters of the western North Atlantic: striped bass (Morone saxatilis), bluefish (Pomatomus saltatrix), summer flounder (Paralichthys dentatus) and cobia (Rachycentron canadum). Benthic summer flounder exhibited higher luminous sensitivity and broader dynamic range than the three pelagic foragers. The former were at the more sensitive end of an emerging continuum for coastal fishes. By contrast, pelagic species were comparatively less sensitive, but showed larger day-night differences, consistent with their use of diel light-variant photic habitats. Flicker fusion frequency experiments revealed significant interspecific differences at maximum intensities that correlated with lifestyle and habitat. Spectral responses of most species spanned 400-610 nm, with significant day-night differences in striped bass and bluefish. Anadromous striped bass additionally responded to longer wavelengths, similar to many freshwater fishes. Collectively, these results suggest that pelagic piscivores are well adapted to bright photoclimates, which may be at odds with the modern state of eutrified coastal and estuarine waters that they utilize. Recent anthropogenic degradation of water quality in coastal environments, at a pace faster than the evolution of visual systems, may impede visually foraging piscivores, change selected prey, and eventually restructure ecosystems. PMID:20435826

  7. Distribution of fallout cesium-137 in the Chesapeake Bay

    International Nuclear Information System (INIS)

    A technique was developed for simple analysis of 137Cs concentrations in water, sediments, and biota in the fractional picocurie per liter range. These measurements are important, since fallout 137Cs will be present in estuarine environments for a generation. The concentration of 137Cs in water is important to studies of distribution coefficients, or concentration factors between water and sediment or organisms. Fallout 137Cs is also a natural tracer, making possible experiments on a span of space and time that is impossible with intentionally added tracers. Thus, one can determine an approximate residence time for a body of brackish water with a few 137Cs concentration measurements, given the average depth and typical fallout deposition rate. This estimate is good enough for first estimates as to the capacity of the body of water for various pollutants. Measurements at several sites, and at all seasonal conditions, can be used to solve the mass and concentration balance equations that more rigorously describe the hydrography of the estuary. (U.S.)

  8. Neoliberalism, the Environmental Protection Agency, and the Chesapeake Bay

    OpenAIRE

    Steffy, Kathryn Marie

    2016-01-01

    Neoliberalism, as the influence of economic considerations within the political process, has impacted environmentalism on a variety of levels. Without regulation, the neoliberal capitalist drive to maximize production, consumption, and profits is antagonistic to environmental sustainability. The influences that corporations and economic elites have within modern democracies holds substantial implications for the rigor and enforcement of environmental policies. Particular to the United Stat...

  9. Optical ages indicate the southwestern margin of the Green Bay Lobe in Wisconsin, USA, was at its maximum extent until about 18,500 years ago

    Science.gov (United States)

    Attig, J.W.; Hanson, P.R.; Rawling, J.E.; Young, A.R.; Carson, E.C.

    2011-01-01

    Samples for optical dating were collected to estimate the time of sediment deposition in small ice-marginal lakes in the Baraboo Hills of Wisconsin. These lakes formed high in the Baraboo Hills when drainage was blocked by the Green Bay Lobe when it was at or very near its maximum extent. Therefore, these optical ages provide control for the timing of the thinning and recession of the Green Bay Lobe from its maximum position. Sediment that accumulated in four small ice-marginal lakes was sampled and dated. Difficulties with field sampling and estimating dose rates made the interpretation of optical ages derived from samples from two of the lake basins problematic. Samples from the other two lake basins-South Bluff and Feltz basins-responded well during laboratory analysis and showed reasonably good agreement between the multiple ages produced at each site. These ages averaged 18.2. ka (n= 6) and 18.6. ka (n= 6), respectively. The optical ages from these two lake basins where we could carefully select sediment samples provide firm evidence that the Green Bay Lobe stood at or very near its maximum extent until about 18.5. ka.The persistence of ice-marginal lakes in these basins high in the Baraboo Hills indicates that the ice of the Green Bay Lobe had not experienced significant thinning near its margin prior to about 18.5. ka. These ages are the first to directly constrain the timing of the maximum extent of the Green Bay Lobe and the onset of deglaciation in the area for which the Wisconsin Glaciation was named. ?? 2011 Elsevier B.V.

  10. Application of Multiple Index Development Approaches to Benthic Invertebrate Data from the Virginian Biogeographic Province, USA

    Science.gov (United States)

    Previous work had indicated that the Virginian Province Index did not perform well in a smaller estuarine complex. While it was hoped that the existing Chesapeake Bay Benthic Index of Biotic Integrity, with its greater number of metrics and habitat separation would be more adapt...

  11. A new species of Apolochus (Crustacea, Amphipoda, Gammaridea, Amphilochidae) in Maryland coastal bays, USA with notes on its abundance and distribution.

    Science.gov (United States)

    Morales-Núñez, Andrés G; Chigbu, Paulinus

    2016-01-01

    A new amphilochid amphipod, Apolochus cresti sp. n. is described from specimens collected in the shallow waters of Maryland coastal bays, Mid-Atlantic region, at depths from 1.7 to 2.1 m. The new species appears to be most closely related to the northeastern Atlantic species, Apolochus neapolitanus sensu Krapp-Schickel, 1982. Apolochus cresti sp. n. can be distinguished from Apolochus neapolitanus by a combination of characters, including the shape of the lateral cephalic lobe, shape of the mandible molar process, relative length of mandible palp article 3, the carpal lobe length of gnathopod 2, and the lack of sub-marginal spines on antero-lateral surface of gnathopod 2. Spearman's rank correlation analysis indicated a positive correlation between the abundance of Apolochus cresti and the amount of macroalgae collected per station, bay, and month. Ovigerous females carrying eggs were present from March to May and in October, reaching their peak in May, although only ovigerous females carrying juveniles were found in May. Males were abundant in March and were collected also in May and October. A key for the separation of Apolochus species is presented. PMID:27110159

  12. Spectral definition of the macro-algae Ulva curvata in the back-barrier bays of the Eastern Shore of Virginia, USA

    Science.gov (United States)

    Ramsey, Elijah W., III; Rangoonwala, Amina; Solgaard, Mads; Schwarzchild, Arthur

    2012-01-01

    We have developed methods to determine the visible (VIS) to near-infrared (NIR) spectral properties of thalli and epiphytes of bloom-forming and green macrophyte Ulva curvata in back-barrier lagoons in Virginia, USA. A 2% increase in NIR thalli reflectance from winter to summer matched the drop in summer NIR transmittance. In contrast, summer and winter VIS reflectance were nearly identical while winter transmittance was 10-20% higher. NIR absorption remained at 5% but VIS absorption increased by 10-20% from winter to summer. Replicate consistency substantiated the high transmittance difference indicating thallus composition changed from summer to winter. Epiphytes increased thallus reflectance and decreased transmittance and exhibited broadband VIS and NIR absorptions in summer and selective peaks in winter. A simulation coupling water extinction with thallus reflectance and transmittance found seven submerged thalli maximized the surface reflectance enhancement.

  13. The Validity Chlorophyll-a Estimation by Sun Induced Fluorescence in Estuarine Waters: An Analysis of Long-term (2003-2011) Water Quality Data from Tampa Bay, Florida (USA)

    Science.gov (United States)

    Moreno-Madrinan, Max Jacobo; Fischer, Andrew

    2012-01-01

    Satellite observation of phytoplankton concentration or chlorophyll-a is an important characteristic, critically integral to monitoring coastal water quality. However, the optical properties of estuarine and coastal waters are highly variable and complex and pose a great challenge for accurate analysis. Constituents such as suspended solids and dissolved organic matter and the overlapping and uncorrelated absorptions in the blue region of the spectrum renders the blue-green ratio algorithms for estimating chlorophyll-a inaccurate. Measurement of sun-induced chlorophyll fluorescence, on the other hand, which utilizes the near infrared portion of the electromagnetic spectrum, may provide a better estimate of phytoplankton concentrations. While modelling and laboratory studies have illustrated both the utility and limitations of satellite baseline algorithms based on the sun induced chlorophyll fluorescence signal, few have examined the empirical validity of these algorithms using a comprehensive long term in situ data set. In an unprecedented analysis of a long term (2003-2011) in situ monitoring data from Tampa Bay, Florida (USA), we assess the validity of the FLH product from the Moderate Resolution Imaging Spectrometer (MODIS) against chlorophyll ]a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions within the estuary including water depth, distance from shore and structures and eight water quality parameters. From the 39 station for which data was derived, 22 stations showed significant correlations when the FLH product was matched with in situ chlorophyll-alpha data. The correlations (r2) for individual stations within Tampa Bay ranged between 0.67 (n=28, pless than 0.01) and-0.457 (n=12, p=.016), indicating that

  14. Short-term variability of 7Be atmospheric deposition and watershed response in a Pacific coastal stream, Monterey Bay, California, USA

    International Nuclear Information System (INIS)

    Beryllium-7 is a powerful and commonly used tracer for environmental processes such as watershed sediment provenance, soil erosion, fluvial and nearshore sediment cycling, and atmospheric fallout. However, few studies have quantified temporal or spatial variability of 7Be accumulation from atmospheric fallout, and parameters that would better define the uses and limitations of this geochemical tracer. We investigated the abundance and variability of 7Be in atmospheric deposition in both rain events and dry periods, and in stream surface-water samples collected over a ten-month interval at sites near northern Monterey Bay (37°N, 122°W) on the central California coast, a region characterized by a rainy winters, dry summers, and small mountainous streams with flashy hydrology. The range of 7Be activity in rainwater samples from the main sampling site was 1.3–4.4 Bq L−1, with a mean (±standard deviation) of 2.2 ± 0.9 Bq L−1, and a volume-weighted average of 2.0 Bq L−1. The range of wet atmospheric deposition was 18–188 Bq m−2 per rain event, with a mean of 72 ± 53 Bq m−2. Dry deposition fluxes of 7Be ranged from less than 0.01 up to 0.45 Bq m−2 d−1, with an estimated dry season deposition of 7 Bq m−2 month−1. Annualized 7Be atmospheric deposition was approximately 1900 Bq m−2 yr−1, with most deposition via rainwater (>95%) and little via dry deposition. Overall, these activities and deposition fluxes are similar to values found in other coastal locations with comparable latitude and Mediterranean-type climate. Particulate 7Be values in the surface water of the San Lorenzo River in Santa Cruz, California, ranged from −1 to 0.6 Bq g−1, with a median activity of 0.26 Bq g−1. A large storm event in January 2010 characterized by prolonged flooding resulted in the entrainment of 7Be-depleted sediment, presumably from substantial erosion in the watershed. There were too few particulate 7Be data over the storm to accurately model a 7Be load

  15. Chesapeake Marshlands National Wildlife Refuge Complex: Comprehensive Conservation Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Chesapeake Marshlands NWR Complex for the next 15 years. This plan outlines the...

  16. Impact of Bay-Breeze Circulations on Surface Air Quality and Boundary Layer Export

    Science.gov (United States)

    Loughner, Christopher P.; Tzortziou, Maria; Follette-Cook, Melanie; Pickering, Kenneth E.; Goldberg, Daniel; Satam, Chinmay; Weinheimer, Andrew; Crawford, James H.; Knapp, David J.; Montzka, Denise D.; Diskin, Glenn S.; Dickerson, Russell R.

    2014-01-01

    Meteorological and air-quality model simulations are analyzed alongside observations to investigate the role of the Chesapeake Bay breeze on surface air quality, pollutant transport, and boundary layer venting. A case study was conducted to understand why a particular day was the only one during an 11-day ship-based field campaign on which surface ozone was not elevated in concentration over the Chesapeake Bay relative to the closest upwind site and why high ozone concentrations were observed aloft by in situ aircraft observations. Results show that southerly winds during the overnight and early-morning hours prevented the advection of air pollutants from the Washington, D.C., and Baltimore, Maryland, metropolitan areas over the surface waters of the bay. A strong and prolonged bay breeze developed during the late morning and early afternoon along the western coastline of the bay. The strength and duration of the bay breeze allowed pollutants to converge, resulting in high concentrations locally near the bay-breeze front within the Baltimore metropolitan area, where they were then lofted to the top of the planetary boundary layer (PBL). Near the top of the PBL, these pollutants were horizontally advected to a region with lower PBL heights, resulting in pollution transport out of the boundary layer and into the free troposphere. This elevated layer of air pollution aloft was transported downwind into New England by early the following morning where it likely mixed down to the surface, affecting air quality as the boundary layer grew.

  17. 77 FR 64980 - Chesapeake Renewable Energy LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2012-10-24

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Chesapeake Renewable Energy LLC; Supplemental Notice That Initial Market... supplemental notice in the above-referenced proceeding of Chesapeake Renewable Energy LLC's application...

  18. 33 CFR 162.40 - Inland waterway from Delaware River to Chesapeake Bay, Del. and Md. (Chesapeake and Delaware Canal).

    Science.gov (United States)

    2010-07-01

    ... section in 33 CFR part 207. ... such owners and operators should be particularly careful to moor or anchor well away from the main ship... anchor in the ship channel. (e) Water skiing. Water skiing in the waterway is prohibited between...

  19. Evaluating the potential effects of hurricanes on long-term sediment accumulation in two micro-tidal sub-estuaries: Barnegat Bay and Little Egg Harbor, New Jersey, U.S.A.

    Science.gov (United States)

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

    2016-01-01

    Barnegat Bay, located along the eastern shore of New Jersey, was significantly impacted by Hurricane Sandy in October 2012. Scientists from the U.S. Geological Survey (USGS) developed a multidisciplinary study of sediment transport and hydrodynamics to understand the mechanisms that govern estuarine and wetland responses to storm forcing. This report details the physical and chemical characteristics of surficial and downcore sediments from two areas within the bay. Eleven sites were sampled in both the central portion of the bay near Barnegat Inlet and in the southern portion of the bay in Little Egg Harbor. Laboratory analyses include Be-7, Pb-210, bulk density, porosity, x-radiographs, and grain-size distribution. These data will serve as a critical baseline dataset for understanding the current sedimentological regime and can be applied to future storms for understanding estuarine and wetland evolution.

  20. Bay breeze influence on surface ozone at Edgewood, MD during July 2011

    OpenAIRE

    Stauffer, Ryan M.; Thompson, Anne M.; Martins, Douglas K.; Clark, Richard D.; Goldberg, Daniel L.; Loughner, Christopher P.; Delgado, Ruben; Dickerson, Russell R.; Stehr, Jeffrey W.; Tzortziou, Maria A.

    2012-01-01

    Surface ozone (O3) was analyzed to investigate the role of the bay breeze on air quality at two locations in Edgewood, Maryland (lat: 39.4°, lon: −76.3°) for the month of July 2011. Measurements were taken as part of the first year of NASA’s “Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality” (DISCOVER-AQ) Earth Venture campaign and as part of NASA’s Geostationary for Coastal and Air Pollution Events Chesapeake Bay Oceanographi...

  1. Bay Breeze Influence on Surface Ozone at Edgewood, MD During July 2011

    Science.gov (United States)

    Stauffer, Ryan M.; Thompson, Anne M.; Martins, Douglas K.; Clark, Richard D.; Goldberg, Daniel L.; Loughner, Christopher P.; Delgado, Ruben; Dickerson, Russell R.; Stehr, Jeffrey W.; Tzortziou, Maria A.

    2012-01-01

    Surface ozone (O3) was analyzed to investigate the role of the bay breeze on air quality at two locations in Edgewood, Maryland (lat: 39.4deg, lon: -76.3deg) for the month of July 2011. Measurements were taken as part of the first year of NASA's "Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality" (DISCOVER-AQ) Earth Venture campaign and as part of NASA's Geostationary for Coastal and Air Pollution Events Chesapeake Bay Oceanographic campaign with DISCOVER-AQ (Geo-CAPE CBODAQ). Geo-CAPE CBODAQ complements DISCOVER-AQ by providing ship-based observations over the Chesapeake Bay. A major goal of DISCOVER-AQ is determining the relative roles of sources, photochemistry and local meteorology during air quality events in the Mid-Atlantic region of the U.S. Surface characteristics, transport and vertical structures of O3 during bay breezes were identified using in-situ surface, balloon and aircraft data, along with remote sensing equipment. Localized late day peaks in O3 were observed during bay breeze days, maximizing an average of 3 h later compared to days without bay breezes. Of the 10 days of July 2011 that violated the U.S. Environmental Protection Agency (EPA) 8 h O3 standard of 75 parts per billion by volume (ppbv) at Edgewood, eight exhibited evidence of a bay breeze circulation. The results indicate that while bay breezes and the processes associated with them are not necessary to cause exceedances in this area, bay breezes exacerbate poor air quality that sustains into the late evening hours at Edgewood. The vertical and horizontal distributions of O3 from the coastal Edgewood area to the bay also show large gradients that are often determined by boundary layer stability. Thus, developing air quality models that can sufficiently resolve these dynamics and associated chemistry, along with more consistent monitoring of O3 and meteorology on and along the complex coastline of Chesapeake Bay must be a

  2. Behaviour of uranium during mixing in the Delaware and Chesapeake estuaries

    International Nuclear Information System (INIS)

    Unequivocal evidence is presented for the removal of uranium in two major estuarine systems of the north-eastern United States: the Delaware and Chesapeake Bays. In both the estuaries, during all seasons but mostly in summer, dissolved uranium shows distinctly non-conservative behaviour at salinities ≤ 5. At salinities above 5, there are no deviations from the ideal dilution line. In these two estuaries as much as 22% of dissolved uranium is removed at low salinities, around salinity 2. This pronounced removal of uranium observed at low salinities has been investigated in terms of other chemical properties measured in the Delaware Estuary. In the zone of uranium removal, dissolved oxygen is significantly depleted and pH goes through a minimum down to 6.8. In the same low salinity regime, total alkalinity shows negative deviation from the linear dilution line and phosphate is removed. Humic acids, dissolved iron and manganese are also rapidly removed during estuarine mixing in this low salinity region. Thus, it appears that removal of uranium is most likely related to those properties of alkalinity and acid-base system of the upper estuary that may destabilize the uranium-carbonate complex. Under these conditions, uranium may associate strongly with phosphates or humic substances and be removed onto particulate phases and deposited within upper estuarine sediments. (author)

  3. 78 FR 44556 - Chesapeake Energy Marketing, Inc. v. Midcontinent Express Pipeline LLC; Notice of Complaint

    Science.gov (United States)

    2013-07-24

    ... Energy Regulatory Commission Chesapeake Energy Marketing, Inc. v. Midcontinent Express Pipeline LLC... Energy Regulatory Commission (Commission), 18 CFR 385.206, Chesapeake Energy Marketing, Inc. (CEMI or...Subscription'' link on the Web site that enables subscribers to receive email notification when a document...

  4. A method for examining the geospatial distribution of CO2 storage resources applied to the Pre-Punta Gorda Composite and Dollar Bay reservoirs of the South Florida Basin, U.S.A

    Science.gov (United States)

    Roberts-Ashby, Tina; Brandon N. Ashby

    2016-01-01

    This paper demonstrates geospatial modification of the USGS methodology for assessing geologic CO2 storage resources, and was applied to the Pre-Punta Gorda Composite and Dollar Bay reservoirs of the South Florida Basin. The study provides detailed evaluation of porous intervals within these reservoirs and utilizes GIS to evaluate the potential spatial distribution of reservoir parameters and volume of CO2 that can be stored. This study also shows that incorporating spatial variation of parameters using detailed and robust datasets may improve estimates of storage resources when compared to applying uniform values across the study area derived from small datasets, like many assessment methodologies. Geospatially derived estimates of storage resources presented here (Pre-Punta Gorda Composite = 105,570 MtCO2; Dollar Bay = 24,760 MtCO2) were greater than previous assessments, which was largely attributed to the fact that detailed evaluation of these reservoirs resulted in higher estimates of porosity and net-porous thickness, and areas of high porosity and thick net-porous intervals were incorporated into the model, likely increasing the calculated volume of storage space available for CO2 sequestration. The geospatial method for evaluating CO2 storage resources also provides the ability to identify areas that potentially contain higher volumes of storage resources, as well as areas that might be less favorable.

  5. Decadal-scale export of nitrogen, phosphorus, and sediment from the Susquehanna River basin, USA: Analysis and synthesis of temporal and spatial patterns.

    Science.gov (United States)

    Zhang, Qian; Ball, William P; Moyer, Douglas L

    2016-09-01

    The export of nitrogen (N), phosphorus (P), and suspended sediment (SS) is a long-standing management concern for the Chesapeake Bay watershed, USA. Here we present a comprehensive evaluation of nutrient and sediment loads over the last three decades at multiple locations in the Susquehanna River basin (SRB), Chesapeake's largest tributary watershed. Sediment and nutrient riverine loadings, including both dissolved and particulate fractions, have generally declined at all sites upstream of Conowingo Dam (non-tidal SRB outlet). Period-of-record declines in riverine yield are generally smaller than those in source input, suggesting the possibility of legacy contributions. Consistent with other watershed studies, these results reinforce the importance of considering lag time between the implementation of management actions and achievement of river quality improvement. Whereas flow-normalized loadings for particulate species have increased recently below Conowingo Reservoir, those for upstream sites have declined, thus substantiating conclusions from prior studies about decreased reservoir trapping efficiency. In regard to streamflow effects, statistically significant log-linear relationships between annual streamflow and annual constituent load suggest the dominance of hydrological control on the inter-annual variability of constituent export. Concentration-discharge relationships revealed general chemostasis and mobilization effects for dissolved and particulate species, respectively, both suggesting transport-limitation conditions. In addition to affecting annual export rates, streamflow has also modulated the relative importance of dissolved and particulate fractions, as reflected by its negative correlations with dissolved P/total P, dissolved N/total N, particulate P/SS, and total N/total P ratios. For land-use effects, period-of-record median annual yields of N, P, and SS all correlate positively with the area fraction of non-forested land but negatively with

  6. Community-Level Response of Fishes and Aquatic Macroinvertebrates to Stream Restoration in a Third-Order Tributary of the Potomac River, USA

    OpenAIRE

    James T. Anderson; Stuart A. Welsh; George T. Merovich; Charneé L. Rose; Stephen M. Selego

    2012-01-01

    Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010). Collector filterers and scrapers replaced collecto...

  7. SYNOPTIC CLIMATOLOGY PREDICTIONS OF FRESHWATER FLOW TO CHESAPEAKE BAY. (R828677C002)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  8. F00413: NOS Hydrographic Survey , Southern Chesapeake Bay Item Investigations, Virginia, 1995-05-19

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  9. F00255: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 1984-05-23

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  10. H11207: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2005-09-12

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  11. H11407: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2005-10-20

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  12. F00260: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 1984-05-23

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  13. H10790: NOS Hydrographic Survey , Northern Chesapeake Bay - Baltimore Harbor, Maryland, 1998-06-30

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  14. F00412A: NOS Hydrographic Survey , Southern Chesapeake Bay Item Investigations, Virginia, 1995-05-24

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  15. H11401: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2005-06-09

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  16. H11027: NOS Hydrographic Survey , Northeast Approach to Chesapeake Bay, Virginia, 2001-07-10

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  17. F00395: NOS Hydrographic Survey , Southern Chesapeake Bay Item Investigations, Virginia, 1994-04-28

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  18. F00412: NOS Hydrographic Survey , Southern Chesapeake Bay Item Investigations, Virginia, 1995-05-24

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  19. H10341: NOS Hydrographic Survey , Entrance to Chesapeake Bay, Virginia, 1990-06-06

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  20. F00387: NOS Hydrographic Survey , Southern Chesapeake Bay Item Investigations, Virginia, 1994-06-03

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  1. H12200: NOS Hydrographic Survey , Approaches to Chesapeake Bay, 2010-10-15

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  2. H11301: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2005-11-15

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  3. H12503: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2012-09-23

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  4. H11652: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2007-05-21

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  5. H10337: NOS Hydrographic Survey , Entrance to Chesapeake Bay, Virginia, 1990-05-20

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  6. H11303: NOS Hydrographic Survey , Approaches to Chesapeake Bay, 2006-07-08

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  7. H12502: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2012-09-28

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  8. H12309: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2011-05-10

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  9. H10343: NOS Hydrographic Survey , Entrance to Chesapeake Bay, Virginia, 1990-06-06

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  10. H12315: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2011-06-12

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  11. H11568: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2006-06-25

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  12. H09978: NOS Hydrographic Survey , Chesapeake Bay, Virginia, 1981-11-06

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  13. H10340: NOS Hydrographic Survey , Entrance to Chesapeake Bay, Virginia, 1990-06-07

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  14. H12201: NOS Hydrographic Survey , Approaches to Chesapeake Bay, 2010-10-24

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  15. H11402: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2005-10-27

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  16. F00607: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2011-10-20

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  17. H07065: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1945-09-06

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  18. H12305: NOS Hydrographic Survey , Central Chesapeake Bay, 2013-12-10

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  19. H12286: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2011-06-01

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  20. H08082: NOS Hydrographic Survey , Chesapeake Bay, Virginia, 1954-09-01

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  1. H10632: NOS Hydrographic Survey , Upper Chesapeake Bay - Baltimore Harbor, Maryland, 1995-09-21

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  2. H12180: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2010-10-10

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  3. F00388: NOS Hydrographic Survey , Southern Chesapeake Bay Item Investigations, Virginia, 1994-03-20

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  4. Nancy Love receives governor's appointment to Chesapeake Bay Scientific and Technical Advisory Committee

    OpenAIRE

    Gilbert, Karen

    2005-01-01

    Nancy Love, associate professor of civil and environmental engineering and adjunct professor of biology at Virginia Tech, has been appointed to the Governor's Scientific and Technical Advisory Committee (STAC).

  5. H12367: NOS Hydrographic Survey , Central Chesapeake Bay, 2012-12-19

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  6. H12304: NOS Hydrographic Survey , Central Chesapeake Bay, MD, 2012-06-18

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  7. H11598: NOS Hydrographic Survey , Central Chesapeake Bay, Maryland, 2008-11-12

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  8. H12267: NOS Hydrographic Survey , Central Chesapeake Bay, Maryland, 2011-03-28

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  9. H12285: NOS Hydrographic Survey , Southern Chesapeake Bay, VA, 2012-07-28

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  10. H10212: NOS Hydrographic Survey , Chesapeake Bay, Craighill Channel Spoil Areas, 1983-08-16

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  11. H07001: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1945-04-11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  12. H06368: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1938-10-20

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  13. H12423: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2012-09-09

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  14. F00308: NOS Hydrographic Survey , Chesapeake Bay, Maryland and Virginia, 1987-11-24

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  15. H11651: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2007-05-21

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  16. 75 FR 78667 - Cooperative Conservation Partnership Initiative-Chesapeake Bay Watershed

    Science.gov (United States)

    2010-12-16

    ..., energy conservation, mitigating the effects of climate change, facilitating climate change adaptation, or... partnership agreement; 6. Budget which includes other funding sources (if applicable) for financial and... address water quality; water conservation; or State, regional, or national conservation initiatives;...

  17. F00602: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2011-06-15

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  18. H11302: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2003-11-05

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  19. H06605: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1940-11-05

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  20. Effects of elevated CO{sub 2} on Chesapeake Bay wetlands. [Progress report, 1988--1989

    Energy Technology Data Exchange (ETDEWEB)

    Drake, B.G.; Arp, W.J.; Balduman, L.

    1990-12-31

    Research during 1988--89 focused on several new aspects of the response of the salt marsh ecosystem to elevated CO{sub 2}. In previous years we gave highest priority to studies of the effect of CO{sub 2} on biomass production into above and below-ground tissues, nitrogen content, light response of photosynthesis of single leaves, leaf water potential and carbon dioxide and water vapor exchange between the plant canopy and the ambient air. Result from the work in 87 and 88 had shown that the C3 plant, Scirpus olneyi, responded vigorously to elevated CO{sub 2} but the two C4 species, Spartina patens and Distichlis spicata did not. The responses of photosynthesis were also reflected in the canopy and ecosystem processes. Thus our emphasis shifted from determining the growth responses to exploring photosynthesis in greater detail. The main questions were: does acclimation to high CO{sub 2} involve reduction of some aspect of photosynthesis either at the single leaf level or in canopy structure? How much more carbon will be accumulated in a high CO{sub 2} than under present CO{sub 2} concentration? Our results give us partial answers to these questions but since the long term aspect of CO{sub 2} stimulation remains the most important one, it is unlikely that we can do more than add some pieces of data to a continuing debate in the ecological community regarding the eventual effect of CO{sub 2} on ecosystems.

  1. H12044: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2009-12-15

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  2. Supercritical fluid extraction applied to environmental pollutants from Chesapeake Bay sediment

    OpenAIRE

    Yang, Karen Y

    1996-01-01

    Sample preparation via supercritical fluid extraction (SFE) has been increasingly used to determine polynuclear aromatic hydrocarbons (P AHs) in environmental samples. As an alternative sample preparation technique, SFE offers the distinct advantages of greatly reduced sample preparation time, concentrated analyte ready for assay, and comparable extraction efficiency to conventional liquid extraction. Supercritical carbon dioxide is the most widely used SFE fluid. Compared to the other superc...

  3. H11656: NOS Hydrographic Survey , Chesapeake Bay, Virginia, 2007-09-28

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  4. H08083: NOS Hydrographic Survey , Chesapeake Bay, Virginia, 1953-10-09

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  5. H11503: NOS Hydrographic Survey , Central Chesapeake Bay, Virginia, 2006-09-18

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  6. H11653: NOS Hydrographic Survey , Chesapeake Bay, Virginia, 2007-09-26

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  7. H12321: NOS Hydrographic Survey , Central Chesapeake Bay, MD, 2011-05-18

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  8. H06376: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1938-11-03

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  9. F00275: NOS Hydrographic Survey , Chesapeake Bay, Maryland and Virginia, 1985-12-11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  10. H12238: NOS Hydrographic Survey , Central Chesapeake Bay, Maryland, 2010-11-12

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  11. H12241: NOS Hydrographic Survey , Central Chesapeake Bay, Maryland, 2010-11-13

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  12. 33 CFR 165.507 - Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD.

    Science.gov (United States)

    2010-07-01

    ... AND LIMITED ACCESS AREAS Specific Regulated Navigation Areas and Limited Access Areas Fifth Coast... first request authorization from the Captain of the Port, Baltimore to seek permission to transit...

  13. H08218: NOS Hydrographic Survey , Entrance to Chesapeake Bay, Virginia, 1954-07-22

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  14. H12040: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2009-12-07

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  15. H12041: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2009-12-15

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  16. F00220: NOS Hydrographic Survey , Wire Drag, East Coast Investigations, Chesapeake Bay, 1979-04-13

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  17. H05327: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1933-11-19

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  18. F00267: NOS Hydrographic Survey , Chesapeake Bay Hurricane Anchorages, Virginia, 1984-06-21

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  19. H05329: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1933-07-18

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  20. Fungi and Bacteria in or on Leaves of Eelgrass (Zostera marina L.) from Chesapeake Bay

    OpenAIRE

    Newell, Steven Y.

    1981-01-01

    Samples of green and brown leaves of eelgrass (Zostera marina L.) were incubated in seawater without an additional carbon source. Parallel leaf samples were used for acridine orange bacterial counting and water-soluble aniline blue estimation of fungal biovolume. The incubations produced no evidence that there is an eelgrass counterpart for the chytridialean symbiont which is very common in turtlegrass (Thalassia testudinum König). Sterile mycelium (i.e., living mycelium without identifiable ...

  1. Incentive encourages dairy farmers to lessen phosphorus pollution in Chesapeake Bay

    OpenAIRE

    Sutphin, Michael D.

    2007-01-01

    Virginia Tech researchers in the Department of Dairy Science in the College of Agriculture and Life Sciences are using a grant from the U.S. Department of Agriculture's Natural Resource Conservation Service (NRCS) to offer incentive payments to dairy farmers who reduce phosphorus overfeeding on their farms. This outreach program follows almost a decade of research on the dietary nutrient management of dairy cattle in Virginia.

  2. 75 FR 17683 - Cooperative Conservation Partnership Initiative-Chesapeake Bay Watershed

    Science.gov (United States)

    2010-04-07

    ... renewable energy production, energy conservation, mitigating the effects of climate change, facilitating... primarily for the production of adapted crops for harvest, including but not limited to land in row crops or... crop production. Designated Conservationist means an NRCS employee whom the State Conservationist...

  3. Disrupted Food Webs: Exploring the Relationship between Overfishing and Dead Zones in the Chesapeake Bay

    Science.gov (United States)

    Wyner, Yael

    2010-01-01

    This inquiry-based activity provides a real-world example that connects to students' everyday seafood choices. In fact, many students went home and insisted to their parents that they should only buy "green" seafood choices. It was also an effective activity because students were able to use what they learned about ocean ecosystems and apply it to…

  4. Spatial Statistical Network Models for Stream and River Temperatures in the Chesapeake Bay Watershed

    Science.gov (United States)

    Numerous metrics have been proposed to describe stream/river thermal regimes, and researchers are still struggling with the need to describe thermal regimes in a parsimonious fashion. Regional temperature models are needed for characterizing and mapping current stream thermal re...

  5. F00306: NOS Hydrographic Survey , Chesapeake Bay, Maryland and Virginia, 1987-10-29

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  6. Detection of luciferase gene sequences in nonluminescent bacteria from the Chesapeake Bay

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chun, J.; Ravel, J.; Straube, W.L.; Hill, R.T.; Colwell, R.R.

    colonizing light or- gans in several marine ¢sh and squid species [4]. Strains of these species have been recognized as visibly luminous and non-visibly luminous based on di¡erential light production on laboratory media. Non-visibly luminous strains (also... termed ‘dark mutants’ [5]) produce low levels of light that can be detected using a photometer [6,7]. Only the non-visibly luminous strains are pro¢cient at colonizing the light organ of the squid Euprymna scalopes under nat- ural conditions where both...

  7. H05328: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1933-11-11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  8. H10757: NOS Hydrographic Survey , Northern Chesapeake Bay, Maryland, 1998-11-11

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Oceanic and Atmospheric Administration (NOAA) has the statutory mandate to collect hydrographic data in support of nautical chart compilation for safe...

  9. Integrated Pest Management Plan for Chesapeake Marshlands National Wildlife Refuge Complex 2012

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — With this Integrated Pest Management Plan, the Chesapeake Marshlands National Wildlife Refuge Complex aims to demonstrate land stewardship in controlling invasive...

  10. San Diego Bay Bibliography

    OpenAIRE

    Brueggeman, Peter

    1994-01-01

    The San Diego Bay Bibliography references the scientific & gray literature on the Bay up through 1994 and it is NOT current. Compiled from numerous resources (including Hubbs-Sea World Research Institute, Regional Water Quality Control Board, & local library catalogs), it is not comprehensive since so the Bay literature is elusive. In addition, there can be duplicate references varying in completeness. The San Diego Bay Bibliography is the outcome of discussion and networking within ...

  11. Phenotypes and Virulence among Staphylococcus aureus USA100, USA200, USA300, USA400, and USA600 Clonal Lineages

    OpenAIRE

    King, Jessica M.; Kulhankova, Katarina; Stach, Christopher S.; Vu, Bao G.; Salgado-Pabón, Wilmara

    2016-01-01

    ABSTRACT Staphylococcus aureus diseases affect ~500,000 individuals per year in the United States. Worldwide, the USA100, USA200, USA400, and USA600 lineages cause many of the life-threatening S. aureus infections, such as bacteremia, infective endocarditis, pneumonia, toxic shock syndrome, and surgical site infections. However, the virulence mechanisms associated with these clonal lineages, in particular the USA100 and USA600 isolates, have been severely understudied. We investigated the vir...

  12. Superflux I, II, and III experiment designs: Water sampling and analyses. [Chespeake Bay, environmental monitoring and remote sensing

    Science.gov (United States)

    Thomas, J. P.

    1981-01-01

    Both airborne remote sensors and seagoing research vessels were used to study the effects of man's continual use of the Chesapeake Bay offshore environments. The major focus of the study was to: (1) advance the development and transfer of improved remote sensing systems and techniques for monitoring environmental quality and effects on living marine resources; (2) increase understanding of the influence of estuarine outwellings (plumes) on contiguous shelf ecosystems; and (3) provide a synoptic, integrated and timely data base for application to problems of marine resources and environmental quality.

  13. Tampa Bay: Chapter N

    Science.gov (United States)

    Handley, Larry; Spear, Kathryn; Cross, Lindsay; Baumstark, René; Moyer, Ryan; Thatcher, Cindy

    2013-01-01

    Tampa Bay is Florida’s largest open-water estuary and encompasses an area of approximately 1036 km2 (400 mi2) (Burgan and Engle, 2006; TBNEP, 2006). The Bay’s watershed drains 5,698 km2 (2,200 mi2) of land and includes freshwater from the Hillsborough River to the north east, the Alafia and Little Manatee rivers to the east, and the Manatee River to the south (Figure 1). Freshwater inflow also enters the bay from the Lake Tarpon Canal, from small tidal tributaries, and from watershed runoff. Outflow travels from the upper bay segments (Hillsborough Bay and Old Tampa Bay) into Middle and Lower Tampa Bay. Southwestern portions of the water shed flow through Boca Ciega Bay into the Intracoastal Waterway and through the Southwest Channel and Passage Key Inlet into the Gulf of Mexico. The average depth in most of Tampa Bay is only 3.4 m (11 ft); however, 129 km (80 mi) of shipping channels with a maximum depth of 13.1 m (43 ft) have been dredged over time and are regularly maintained. These channels help to support the three ports within the bay, as well as commercial and recreational boat traffic.

  14. The monterey bay broadband ocean bottom seismic observatory

    OpenAIRE

    Romanowicz, B.; Seismological Laboratory, University of California, Berkeley; Stakes, D.; Monterey Bay Aquarium Research Institute; Dolenc, D.; Seismological Laboratory, University of California, Berkeley; Neuhauser, D.; Seismological Laboratory, University of California, Berkeley; McGill, P.; Monterey Bay Aquarium Research Institute; Uhrhammer, R.; Seismological Laboratory, University of California, Berkeley; Ramirez, T.; Monterey Bay Aquarium Research Institute

    2006-01-01

    We report on the installation of a long-term buried ocean-floor broadband seismic station (MOBB) in Monterey Bay, California (USA), 40km off-shore, at a water depth of 1000 m. The station was installed in April 2002 using a ship and ROV, in a collaborative effort between the Monterey Bay Aquarium Research Institute (MBARI) and the Berkeley Seismological Laboratory (BSL). The station is located on the western side of the San Gregorio Fault, a major fault in the San Andreas plate...

  15. The monterey bay broadband ocean bottom seismic observatory

    OpenAIRE

    R. Uhrhammer; McGill, P; Neuhauser, D; D. Dolenc; D. Stakes; B. Romanowicz; Ramirez, T.

    2006-01-01

    We report on the installation of a long-term buried ocean-floor broadband seismic station (MOBB) in Monterey Bay, California (USA), 40km off-shore, at a water depth of 1000 m. The station was installed in April 2002 using a ship and ROV, in a collaborative effort between the Monterey Bay Aquarium Research Institute (MBARI) and the Berkeley Seismological Laboratory (BSL). The station is located on the western side of the San Gregorio Fault, a major fault in the San Andreas plate boundary fault...

  16. eBay.com

    DEFF Research Database (Denmark)

    Engholm, Ida

    2014-01-01

    Celebrated as one of the leading and most valuable brands in the world, eBay has acquired iconic status on par with century-old brands such as Coca-Cola and Disney. The eBay logo is now synonymous with the world’s leading online auction website, and its design is associated with the company...

  17. Regional Simulation of Groundwater Transport of Nitrate in the Delmarva Peninsula, USA (Invited)

    Science.gov (United States)

    Sanford, W. E.

    2009-12-01

    The Chesapeake Bay has been suffering from degraded water quality for a number of decades. One large cause of the problem has been increased delivery of nitrogen to the bay by groundwater and surface water. The nitrogen originates at the land surface throughout the watershed from a variety of locations that include point sources of wastewater discharge and diffuse sources of fertilizer and wastes from agriculture and suburbia. To date much of the efforts to simulate the movement of nitrogen to the bay have focused around a surface-water-dominated watershed model created for the bay watershed. Independent studies, however, indicate that most of the nitrate being delivered to the bay is through groundwater, and the associated groundwater lag time is not being accounted for in the watershed model. A major effort is now underway to simulate the groundwater transport of nitrate to the bay. These simulations will cover several large sections of the watershed and will be used to estimate the magnitude and distribution of groundwater lag times, and to help land managers target areas to reduce nitrogen loading. Four MODFLOW models of sections of the bay watershed are being constructed. The first of these covers the Maryland and Delaware sections of the Delmarva Peninsula. The Delmarva model is of the shallow unconfined aquifer (denitrification) above the water table from fertilizer and manure, respectively. Also, denitrification occurs during groundwater transport with an average first order rate loss constant of 0.033 per year. Finally, 10 to 20 percent of the remaining nitrate is lost in the stream-riparian corridor. The median age of water reaching the streams in the various smaller watersheds ranges between 10 and 40 years. Simulated forecasts of future nitrate levels in the streams indicate that levels should take years to decades to respond substantially to changes in loadings at the land surface.

  18. TEMPORAL AND SPATIAL VARIATION IN PLASMA THYROXINE (T4) CONCENTRATIONS IN JUVENILE ALLIGATORS COLLECTED FROM LAKE OKEECHOBEE AND THE NORTHERN EVERGLADES, FLORIDA, USA

    Science.gov (United States)

    We examined variation in plasma thyroxine (T4) in juvenile American alligators (Alligator mississippiensis) collected from three sites within the Kissimmee River drainage basin (FL, USA). Based on historical sediment data, Moonshine Bay served as the low contaminant exposure site...

  19. Phenotypes and Virulence among Staphylococcus aureus USA100, USA200, USA300, USA400, and USA600 Clonal Lineages.

    Science.gov (United States)

    King, Jessica M; Kulhankova, Katarina; Stach, Christopher S; Vu, Bao G; Salgado-Pabón, Wilmara

    2016-01-01

    Staphylococcus aureus diseases affect ~500,000 individuals per year in the United States. Worldwide, the USA100, USA200, USA400, and USA600 lineages cause many of the life-threatening S. aureus infections, such as bacteremia, infective endocarditis, pneumonia, toxic shock syndrome, and surgical site infections. However, the virulence mechanisms associated with these clonal lineages, in particular the USA100 and USA600 isolates, have been severely understudied. We investigated the virulence of these strains, in addition to strains in the USA200, USA300, and USA400 types, in well-established in vitro assays and in vivo in the rabbit model of infective endocarditis and sepsis. We show in the infective endocarditis and sepsis model that strains in the USA100 and USA600 lineages cause high lethality and are proficient in causing native valve infective endocarditis. Strains with high cytolytic activity or producing toxic shock syndrome toxin 1 (TSST-1) or staphylococcal enterotoxin C (SEC) caused lethal sepsis, even with low cytolytic activity. Strains in the USA100, USA200, USA400, and USA600 lineages consistently contained genes that encode for the enterotoxin gene cluster proteins, SEC, or TSST-1 and were proficient at causing infective endocarditis, while the USA300 strains lacked these toxins and were deficient in promoting vegetation growth. The USA100, USA200, and USA400 strains in our collection formed strong biofilms in vitro, whereas the USA200 and USA600 strains exhibited increased blood survival. Hence, infective endocarditis and lethal sepsis are multifactorial and not intrinsic to any one individual clonal group, further highlighting the importance of expanding our knowledge of S. aureus pathogenesis to clonal lineages causative of invasive disease. IMPORTANCE S. aureus is the leading cause of infective endocarditis in the developed world, affecting ~40,000 individuals each year in the United States, and the second leading cause of bacteremia (D. R

  20. DIGITAL FLOOD INSURANCE RATE MAP DATABASE, BAY COUNTY, FLORIDA, USA

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk...

  1. Bathymetry in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 4x4 meter resolution bathymetric surface for Jobos Bay, Puerto Rico (in NAD83 UTM 19 North). The depth values are in meters referenced to...

  2. Hammond Bay Biological Station

    Data.gov (United States)

    Federal Laboratory Consortium — Hammond Bay Biological Station (HBBS), located near Millersburg, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). HBBS was established by...

  3. Logy Bay Fishing Settlement

    OpenAIRE

    S H Parsons and Sons

    2003-01-01

    202 x 151 mm. Showing the small inlet with moored rowing boats and rough wooden shacks built on the cliffside. Lying about seven miles from St. John's, Logy Bay was used as a summertime fishing station.

  4. Biscayne Bay Alongshore Epifauna

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Field studies to characterize the alongshore epifauna (shrimp, crabs, echinoderms, and small fishes) along the western shore of southern Biscayne Bay were started...

  5. Humboldt Bay Orthoimages

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of 0.5-meter pixel resolution, four band orthoimages covering the Humboldt Bay area. An orthoimage is remotely sensed image data in which...

  6. USA tankid tulevad Eestisse

    Index Scriptorium Estoniae

    2015-01-01

    USA on valmis Balti riikidesse ladustama lahingutanke, jalavämasinaid ja muud raskerelvastust. Eestisse paigutatakse sellisel juhul sõjatehnikat 150 USA sõjaväelase jaoks. Selline otsus peaks langetatama juba järgmisel nädalal

  7. The Fermi's Bayes Theorem

    CERN Document Server

    D'Agostini, G

    2005-01-01

    It is curious to learn that Enrico Fermi knew how to base probabilistic inference on Bayes theorem, and that some influential notes on statistics for physicists stem from what the author calls elsewhere, but never in these notes, {\\it the Bayes Theorem of Fermi}. The fact is curious because the large majority of living physicists, educated in the second half of last century -- a kind of middle age in the statistical reasoning -- never heard of Bayes theorem during their studies, though they have been constantly using an intuitive reasoning quite Bayesian in spirit. This paper is based on recollections and notes by Jay Orear and on Gauss' ``Theoria motus corporum coelestium'', being the {\\it Princeps mathematicorum} remembered by Orear as source of Fermi's Bayesian reasoning.

  8. EFFECTS OF DDT SEDIMENT-CONTAMINATION ON MACROFAUNAL COMMUNITY STRUCTURE AND COMPOSITION IN SAN FRANCISCO BAY

    Science.gov (United States)

    The objectives of this study were to determine the effects of sediment contamination on the benthic macrofauna and to predict macrofaunal changes following remediation at a Superfund (uncontrolled hazardous waste) site in San Francisco Bay, CA, USA. DDT and its metabolites (sumDD...

  9. Humic Substances from Manila Bay and Bolinao Bay Sediments

    OpenAIRE

    Elma Llaguno

    1997-01-01

    The C,H,N composition of sedimentary humic acids (HA) extracted from three sites in Manila Bay and six sites in Bolinao Bay yielded H/C atomic ratios of 1.1-1.4 and N/C atomic ratios of 0.09 - 0.16. The Manila Bay HA's had lower H/C and N/C ratios compared to those from Bolinao Bay. The IR spectra showed prominent aliphatic C-H and amide I and II bands. Manila Bay HA's also had less diverse molecular composition based on the GC-MS analysis of the CuO and alkaline permanganate oxidation produc...

  10. Humic substances from Manila Bay and Bolinao Bay sediments

    International Nuclear Information System (INIS)

    The C, H, N composition of sedimentary humic acids (HA) extracted from three sites in Manila Bay and six sites in Bolinao Bay yielded H/C atomic ratios of 1.1-1.4 and N/C atomic ratios of 0.09-0.16. The Manila Bay HA's had lower H/C and C/C ratios compared to those from Bolinao Bay. The IR spectra showed prominent aliphatic C-H amide I and II bands. Manila Bay HA's also had less diverse molecular composition based on the GC-MS analysis of the CuO and alkaline permanganate oxidation products of the humic acids. (Author)

  11. Monterey Bay geoid

    OpenAIRE

    Boener, Joseph H.

    1994-01-01

    A high resolution local geoid was calculated for the Monterey Bay, CA using local gravimetry data, digital elevation data and The Ohio State University OSU91A global geopotential model. The theoretical accuracy of the calculated local geoid is 3.5 cm or better over 5 km. Local gravity data came from three sources: 1,549 land observations from the Defense Mapping Agency, 179 bottom gravity observations from two Naval Postgraduate School gravity surveys of Monterey Bay and 17,098 National Geode...

  12. Inter-Comparison between VIIRS and MODIS Radiances and Ocean Color Data Products over the Chesapeake Bay

    OpenAIRE

    Rong-Rong Li; Mark David Lewis; Richard W. Gould; Adam Lawson; Ruhul Amin; Sonia C. Gallegos; Sherwin Ladner

    2015-01-01

    Since the October 2011 launch of the VIIRS (Visible Infrared Imaging Radiometer Suite) instrument, a number of inter-sensor comparisons between VIIRS and MODIS (Moderate Resolution Imaging Spectroradiometer) radiances have been reported. Most of these comparisons are between calibrated radiances and temperatures based on observations of the two sensors from simultaneous nadir overpasses (SNO). Few comparisons between the retrieved ocean color data products, such as chlorophyll concentration, ...

  13. Stormwater Management in Response to Climate Change Impacts: Lessons from the Chesapeake Bay and Great Lakes Regions (Final Report)

    Science.gov (United States)

    This report was prepared by the U.S. Environmental Protection Agency’s (EPA) Air, Climate, and Energy (ACE) research program, located within the Office of Research and Development, with support from ICF International. One of the goals of the ACE research program is to provide sci...

  14. Ephemeral Dissolved Organic Carbon Fluxes from Agricultural Runoff on the Virginia Coastal Plain in the Chesapeake Bay Watershed

    Science.gov (United States)

    Caverly, E. K.; Kaste, J. M.; Hancock, G. S.; Cammer, S. S.

    2011-12-01

    Dissolved organic carbon (DOC) plays a critical role in nutrient cycling and contaminant transport, but DOC fluxes are not well constrained across different land uses and environments. Recent work has shown that agricultural runoff can have high DOC contents due to leaching of crop residues and soil organic matter by rain and irrigation waters. While riparian buffers are assumed to protect surface waters from agricultural runoff, on some fields, the natural topography can concentrate runoff to such an extent that a channel is incised. These channels can become ephemeral pathways for agricultural runoff to exit fields and enter nearby perennial streams without substantial contact with the riparian buffer. We use automated high resolution sampling of agricultural storm runoff and stream height to quantify DOC fluxes and dynamics in a single channel on the coastal plain of Virginia. We also assess dissolved organic matter as a source of organically bound nitrogen and phosphorus in this environment. Discharge measurements for flux calculations are determined with rating curves developed using stream stage height and salt dilution measurements for individual storms. We quantify DOC and major nutrients using ion chromatography, high temperature catalytic oxidation, and specific absorbance measurements at 254 nm. We determine N and P pools using UV digestion followed by ion chromatography. For a single storm event, specific absorbance at 254 nm increases as the hydrograph progresses, suggesting that water with a longer field residence time leaches more DOC as it is transported to the monitoring site. It is anticipated that the antecedent field conditions, particularly the degree of saturation from previous rain events, strongly influence the fluxes and character of DOC from an agricultural watershed. While ephemeral channels are often overlooked as sources of agricultural runoff, we find that they can facilitate the export of large quantities of DOC and nutrients during flashy, storm generated flows.

  15. Impact of legacy phosphorus sources on diffuse phosphorus pollution from agriculture: lessons from the Chesapeake Bay watershed

    Science.gov (United States)

    Legacy phosphorus (P), the accumulation of P in soils and sediments due to past agricultural management activities, represents an emerging challenge to ongoing efforts to mitigate diffuse P pollution from agriculture. Nutrient management programs, already tasked with minimizing the effects of today...

  16. 33 CFR 334.210 - Chesapeake Bay, in vicinity of Tangier Island; naval guided missiles test operations area.

    Science.gov (United States)

    2010-07-01

    ... their normal course through the area with all practicable speed. (7) All projectiles, bombs and rockets... will not be responsible for damages by such projectiles, bombs, or rockets to nets, traps, buoys,...

  17. GENETIC DIVERSITY OF VIBRIO CHOLERAE IN CHESAPEAKE BAY DETERMINED BY AMPLIFIED FRAGMENT LENGTH POLYMORPHISM FINGERPRINTING. (R824995)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  18. DISEASE INCIDENCE AND POTENTIAL MECHANISMS OF DEFENSE FOR MSX-RESISTANT AND -SUSCEPTIBLE EASTERN OYSTERS HELD IN CHESAPEAKE BAY

    Science.gov (United States)

    A disease of eastern oysters, Crassostreaco virginica(Gmelm, 1791), caused by a protistan, Haplosporidium nelsoni, has caused great losses in the oyster fisheries of the northern Atlantic coast of North America. Certain oyster stocks have been selectively bred to survive infectio...

  19. Accounting for Transaction Costs in Point/Nonpoint Water Quality Trading Programs in the Chesapeake Bay Watershed

    OpenAIRE

    Ribaudo, Marc; McCann, Laura M.J.

    2012-01-01

    Transaction costs are commonly identified as a major reason why so few point/nonpoint trades have occurred in water quality trading programs. We examine the transaction costs to buyers and sellers in Pennsylvania's trading program, and compare them to baseline costs.

  20. 33 CFR 207.160 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Science.gov (United States)

    2010-07-01

    ... contract lock operator except that the responsibility for enforcing all laws, rules and regulations shall... properly and securely assembled. The passage of “bag” or “sack” rafts, “dog” rafts, or of loose logs...

  1. 75 FR 62358 - Stakeholder Input on Stormwater Rulemaking Related to the Chesapeake Bay; Notice of Public Meeting

    Science.gov (United States)

    2010-10-08

    ... industrial activity. EPA published the final Phase I rule on November 16, 1990 (55 FR 47990). See 40 CFR 122... discharges. 64 FR 68722. With respect to MS4s, the Phase I regulations are primarily application requirements..., universities, large hospital or prison complexes, and highways are also included in the definition of...

  2. 33 CFR 165.505 - Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland.

    Science.gov (United States)

    2010-07-01

    ... REGULATED NAVIGATION AREAS AND LIMITED ACCESS AREAS Specific Regulated Navigation Areas and Limited Access... number 410-576-2693 or on VHF channel 16 (156.8 MHz) to seek permission to transit the area....

  3. The Effect of Dissolved Polyunsaturated Aldehydes on Microzooplankton Growth Rates in the Chesapeake Bay and Atlantic Coastal Waters

    OpenAIRE

    Peter J. Lavrentyev; Gayantonia Franzè; Pierson, James J.; Stoecker, Diane K.

    2015-01-01

    Allelopathy is wide spread among marine phytoplankton, including diatoms, which can produce cytotoxic secondary metabolites such as polyunsaturated aldehydes (PUA). Most studies on diatom-produced PUA have been dedicated to their inhibitory effects on reproduction and development of marine invertebrates. However, little information exists on their impact on key herbivores in the ocean, microzooplankton. This study examined the effects of dissolved 2E,4E-octadienal and 2E,4E-heptadienal on the...

  4. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    OpenAIRE

    Kirwan, M. L.; Langley, J.A.; Guntenspergen, G.R.; J. P. Megonigal

    2013-01-01

    The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, in...

  5. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    OpenAIRE

    Kirwan, M. L.; Langley, J.A.; Guntenspergen, G.R.; J. P. Megonigal

    2012-01-01

    The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organ...

  6. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    OpenAIRE

    Kirwan, M. L.; Langley, J.A.; Guntenspergen, G.R.; J. P. Megonigal

    2013-01-01

    The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organ...

  7. Use of a chiA probe for detection of chitinase genes in bacteria from the Chesapeake Bay

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Hill, R.T.; Chun, J.; Ravel, J.; Matte, M.H.; Straube, W.L.; Colwell, R.R.

    from several distantly re- lated bacteria facilitated selection of highly conserved re- gions of the chiA gene for design of PCR primers expected to have broad speci¢city for detection of chiA in a wide range of bacteria. Our aims were to construct a...,34]. In the present study, chiA gene-speci¢c PCR primers and a chiA gene probe were developed and their speci¢city veri¢ed using a large assemblage of reference strains. The chiA frag- ments ampli¢ed by PCR from representative strains were sequenced to con...

  8. Yaquina Bay Topobathy DEM

    Science.gov (United States)

    The U.S.EPA contracted with the U.S.ACE to obtain intertidal and subtidal bathymetric soundings of Yaquina Bay between Poole Slough and the South Beach Marina in 2002. These data were compiled with U.S.ACE subtidal soundings from 1999, 1998, 2000 and National Ocean Service soundi...

  9. USA Hire Testing Platform

    Data.gov (United States)

    Office of Personnel Management — The USA Hire Testing Platform delivers tests used in hiring for positions in the Federal Government. To safeguard the integrity of the hiring processes and ensure...

  10. Trends in counts of manatees Trichechus manatus latirostris from 1987 to 2006 in waters of Sarasota County, Florida, USA

    OpenAIRE

    Scolardi, Kerri M.; Schwacke, Lori H.; Koelsch, Jessica K.; Reynolds III, John E.; Kessenich, Teresa J.; Sprinkel, Jay M.; Gannon, Janet G.

    2009-01-01

    To demonstrate the utility of distributional surveys for assessing relative abundance and trends in counts for a discrete area of coastline, aerial survey data from Sarasota County, Florida, USA, were analyzed for the years 1987 to 2006. The study area was divided into 3 regions: the Sarasota Bay Region (SBR; N = 353 surveys), Lemon Bay (N = 368), and the Myakka River (N = 209). Manatee counts varied significantly across seasons (p < 0.0001) for all 3 regions. Manatees within Sarasota County ...

  11. The combined role of bay and shelf modes in tsunami amplification along the coast

    Science.gov (United States)

    Bellotti, G.; Briganti, R.; Beltrami, G. M.

    2012-08-01

    The role of free modes of oscillation of coastal areas in tsunami amplification at the coast is investigated here. A finite element numerical model for modal analysis was applied and the numerically calculated natural frequencies were compared to those resulting from the spectra of measured sea level time series. Two case studies have been selected: that of Poverty Bay (New Zealand); and that of Kuluk Bay (Adak Island, Alaska, USA). The natural modes of the sea areas that extend in front of these locations are shown to play an important role in tsunami amplification at both the considered bays. In fact, the enhancement of wave height is found to be related to both the small-scale resonance controlled by the coastal shape, and the large-scale one governed by the continental shelf bathymetry. In particular, the model application to Poverty Bay reveals that some of the continental shelf modes are more energetic and occur at frequencies higher than the bay fundamental one. These modes are identified as both cross-shelf modes and trapped edge waves. On the other hand, the application to Kuluk Bay shows that geographical entrapment can be relevant for chain islands, making the bay and the continental shelf modes almost coincident.

  12. Upper Newport Bay Restoration Plan

    OpenAIRE

    Halsch, Chris; Wessling, Jaenna; Lister, Anne; Beck, Emily; Zembel, Richard; Yurko, Matt; Kimball, Sarah

    2016-01-01

    The overall goal of this restoration plan is to assist stakeholders in matching restoration projects with funding opportunities in order to increase the overall health of the Upper Newport Bay. Specifically, this document aims to assess current health and quality of native habitats in and around the bay, and to identify areas needing restoration. We have compiled data on the ecology of the bay, including extent of non-native plant invasion, restoration history and progress, site accessibility...

  13. BCDC Bay Trail Alignment 2009

    Data.gov (United States)

    California Department of Resources — The Bay Trail provides easily accessible recreational opportunities for outdoor enthusiasts, including hikers, joggers, bicyclists and skaters. It also offers a...

  14. The USA PATRIOT Act.

    Science.gov (United States)

    Minow, Mary; Coyle, Karen; Kaufman, Paula

    2002-01-01

    Explains the USA PATRIOT (Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism) Act, passed after the September 11 terrorist attacks, and its implications for libraries and patron records. Considers past dealings with the FBI; court orders; search warrants; wiretaps; and subpoenas. Includes:…

  15. Baltimaade kunsti turnee USAs

    Index Scriptorium Estoniae

    1998-01-01

    5. nov.-st USA Lõuna-Carolina osariigis Wellington B. Grey galeriis ja Jenkins Fine Art Center's 13 eesti, läti ja leedu kunstniku näitus, mis hakkab kolme aasta jooksul ringlema Ameerikas. Eksponeeritud fotokunst, video, installatsioon, joonistused. Kuraator Peeter Linnap ja Mari Laanemets peavad ettekande näituse avamisega samal ajal toimuval Fotohariduse Ühingu konverentsil

  16. Valitsus toetab USA kaitseinvesteeringuid

    Index Scriptorium Estoniae

    2015-01-01

    Valitsus kiitis heaks kokkuleppe, mis võimaldab USA relvajõududel kasutada kaitseväe valduses olevaid alasid ja ehitisi ning teha seal vajalikke ehitustöid. Kokkuleppe kohaselt võivad ameeriklased ehitustöid teha Ämari lennubaasis, keskpolügoonil ja Tapa linnakus

  17. Humic Substances from Manila Bay and Bolinao Bay Sediments

    Directory of Open Access Journals (Sweden)

    Elma Llaguno

    1997-12-01

    Full Text Available The C,H,N composition of sedimentary humic acids (HA extracted from three sites in Manila Bay and six sites in Bolinao Bay yielded H/C atomic ratios of 1.1-1.4 and N/C atomic ratios of 0.09 - 0.16. The Manila Bay HA's had lower H/C and N/C ratios compared to those from Bolinao Bay. The IR spectra showed prominent aliphatic C-H and amide I and II bands. Manila Bay HA's also had less diverse molecular composition based on the GC-MS analysis of the CuO and alkaline permanganate oxidation products of the humic acids.

  18. Guantanamo rikub USA seadusi / Krister Paris

    Index Scriptorium Estoniae

    Paris, Krister

    2003-01-01

    Kaks USA tsiviilkohut leiavad oma otsuses, et USA valitsus rikub USA-s ja Guantanamo sõjaväebaasis kinnipeetavate nn. vaenlasvõitlejate õigusi. Inimõigusorganisatsioonid avaldavad heameelt kohtute otsuste üle

  19. Hydrophobic organochlorine compounds sequestered in submersed aquatic macrophytes (Hydrilla yerticillata (L.f.) Royle) from the tidal Potomac River (USA)

    Science.gov (United States)

    Hopple, J.A.; Foster, G.D.

    1996-01-01

    The potential for hydrophobic organochlorine contaminants to be sequestered in submersed aquatic vegetation was evaluated by determining the concentrations of cis- and trans-chlordane, dieldrin, and polychlorinated biphenyls (PCBs) in feral aquatic macrophytes (Hydrilla verticillata (L.f.) Royle) collected from the tidal Potomac River. Similarities in mean dry-weight concentrations of the identified organochlorine compounds in H. verticillata and surrounding alluvial sediments indicated that the extent of sequestration in H. verticillata was of the same magnitude as sorption of these compounds to river sediments, but some qualitative differences in PCB congener profiles existed. The results imply that to some degree H. verticillata can influence downstream fluxes of organic contaminants in fluvial transport in the Potomac River, and, furthermore, identify this species as a viable candidate organism for hydrophobic organochlorine contaminant biomonitoring in the Chesapeake Bay estuary.

  20. Histologic findings in free-ranging Sarasota Bay bottlenose dolphin (Tursiops truncatus) skin: mercury, selenium, and seasonal factors.

    Science.gov (United States)

    Miller, Debra L; Woshner, Victoria; Styer, Eloise L; Ferguson, Sylvia; Knott, Katrina K; Gray, Matthew J; Wells, Randall S; O'Hara, Todd M

    2011-10-01

    Full-thickness epidermal biopsy samples were collected from free-ranging common bottlenose dolphins (Tursiops truncatus) in Sarasota Bay, Florida, USA. Season (summer or winter) of collection, mercury (Hg) concentration, and selenium (Se) concentration were compared to histologic parameters. Epidermal Hg concentration was positively related to age (Pwinter (Pdolphin health need further investigation. PMID:22102676

  1. Bioinvasion in a Brazilian bay: filling gaps in the knowledge of southwestern Atlantic biota.

    Directory of Open Access Journals (Sweden)

    Barbara L Ignacio

    Full Text Available BACKGROUND: Biological invasions are a major cause of global species change. Nevertheless, knowledge about the distribution and ecology of introduced species is regionally biased, and many gaps in knowledge exist for most developing countries. METHODOLOGY/PRINCIPAL FINDINGS: To study the zoobenthos on the hard substratum of the Ilha Grande Bay, a survey was conducted on both natural and artificial substrata at three depths and seven sites. The species recorded were classified as native, cryptogenic or introduced. Multivariate analyses were conducted to assess the prevalence of introduced species in these communities and to compare the distribution of species on natural and artificial substrata of this bay to identify possible discrepancies in habitat use. Of the 61 species, 25 were cryptogenic, 10 were introduced and 26 were native. Similar numbers of introduced species were found on both natural and artificial substrata, though the community composition was significantly different between them. We also compared the species composition of the Ilha Grande Bay survey to other inventories taken around the world. The highest similarities were found between the Ilha Grande Bay inventory and the Atlantic coastal region (Tampa Bay, USA and the Gulf of Mexico, American Samoa and Pearl Harbor (USA inventories. CONCLUSIONS/SIGNIFICANCE: This study presents the first published comprehensive list of hard substratum sessile marine invertebrate species in a Brazilian bay. The high percentage of cryptogenic species reveals gaps in both zoological records and information on introduced species for the Brazilian coast. The introduced species successfully colonized different sites in the Ilha Grande Bay, including both natural and artificial substrata. In addition, we find that artificial structures may not be good surrogates for natural rocky shores and may represent an ecological threat. Comparisons with other inventories suggest a history of broad

  2. The impact of changing climate on phenology, productivity, and benthic-pelagic coupling in Narragansett Bay

    Science.gov (United States)

    Nixon, Scott W.; Fulweiler, Robinson W.; Buckley, Betty A.; Granger, Stephen L.; Nowicki, Barbara L.; Henry, Kelly M.

    2009-03-01

    The timing and magnitude of phytoplankton blooms have changed markedly in Narragansett Bay, RI (USA) over the last half century. The traditional winter-spring bloom has decreased or, in many years, disappeared. Relatively short, often intense, diatom blooms have become common in spring, summer, and fall replacing the summer flagellate blooms of the past. The annual and summer mean abundance (cell counts) and biomass (chl a) of phytoplankton appear to have decreased based on almost 50 years of biweekly monitoring by others at a mid bay station. These changes have been related to warming of the water, especially during winter, and to increased cloudiness. A significant decline in the winter wind speed may also have played a role. The changes in the phenology of the phytoplankton and the oligotrophication of the bay appear to have decreased greatly the quantity and (perhaps) quality of the organic matter being deposited on the bottom of the bay. This decline has resulted in a very much reduced benthic metabolism as reflected in oxygen uptake, nutrient regeneration, and the magnitude and direction of the net flux of N 2 gas. Based on many decades of standard weekly trawls carried out by the Graduate School of Oceanography, the winter biomass of bottom feeding epibenthic animals has also declined sharply at the mid bay station. After decades of relatively constant anthropogenic nitrogen loading (and declining phosphorus loading), the fertilization of the bay will soon be reduced during May-October due to implementation of advanced wastewater treatment. This is intended to produce an oligotrophication of the urban Providence River estuary and the Upper Bay. The anticipated decline in the productivity of the upper bay region will probably decrease summer hypoxia in that area. However, it may have unanticipated consequences for secondary production in the mid and lower bay where climate-induced oligotrophication has already much weakened the historically strong benthic

  3. Legacy effects of colonial millponds on floodplain sedimentation, bank erosion, and channel morphology, MID-Atlantic, USA

    Science.gov (United States)

    Schenk, E.R.; Hupp, C.R.

    2009-01-01

    Many rivers and streams of the Mid-Atlantic Region, United States (U.S.) have been altered by postcolonial floodplain sedimentation (legacy sediment) associated with numerous milldams. Little Conestoga Creek, Pennsylvania, a tributary to the Susquehanna River and the Chesapeake Bay, is one of these streams. Floodplain sedimentation rates, bank erosion rates, and channel morphology were measured annually during 2004-2007 at five sites along a 28-km length of Little Conestoga Creek with nine colonial era milldams (one dam was still in place in 2007). This study was part of a larger cooperative effort to quantify floodplain sedimentation, bank erosion, and channel morphology in a high sediment yielding region of the Chesapeake Bay watershed. Data from the five sites were used to estimate the annual volume and mass of sediment stored on the floodplain and eroded from the banks for 14 segments along the 28-km length of creek. A bank and floodplain reach based sediment budget (sediment budget) was constructed for the 28 km by summing the net volume of sediment deposited and eroded from each segment. Mean floodplain sedimentation rates for Little Conestoga Creek were variable, with erosion at one upstream site (-5 mm/year) to deposition at the other four sites (highest = 11 mm/year) despite over a meter of floodplain aggradation from postcolonial sedimentation. Mean bank erosion rates range between 29 and 163 mm/year among the five sites. Bank height increased 1 m for every 10.6 m of channel width, from upstream to downstream (R2 = 0.79, p legacy sediment. ?? 2009 American Water Resources Association.

  4. Bayes Multiple Decision Functions

    CERN Document Server

    Wu, Wensong

    2011-01-01

    This paper deals with the problem of simultaneously making many (M) binary decisions based on one realization of a random data matrix X. M is typically large and X will usually have M rows associated with each of the M decisions to make, but for each row the data may be low dimensional. A Bayesian decision-theoretic approach for this problem is implemented with the overall loss function being a cost-weighted linear combination of Type I and Type II loss functions. The class of loss functions considered allows for the use of the false discovery rate (FDR), false nondiscovery rate (FNR), and missed discovery rate (MDR) in assessing the decision. Through this Bayesian paradigm, the Bayes multiple decision function (BMDF) is derived and an efficient algorithm to obtain the optimal Bayes action is described. In contrast to many works in the literature where the rows of the matrix X are assumed to be stochastically independent, we allow in this paper a dependent data structure with the associations obtained through...

  5. USA-USSR protocol

    CERN Multimedia

    1970-01-01

    On 30 November the USA Atomic Energy Commission and the USSR State Committee for the Utilization of Atomic Energy signed, in Washington, a protocol 'on carrying out of joint projects in the field of high energy physics at the accelerators of the National Accelerator Laboratory (Batavia) and the Institute for High Energy Physics (Serpukhov)'. The protocol will be in force for five years and can be extended by mutual agreement.

  6. Use of a Metolachlor Metabolite (MESA) to Assess Agricultural Nitrate-N Fate and Transport in Choptank River Watershed, Maryland USA

    Science.gov (United States)

    McCarty, Greg; Hapeman, Cathleen; Rice, Clifford; Hively, Dean; McConnell, Laura; Sadeghi, Ali; Lang, Megan; Whitall, David; Bialek, Krystyna; Downey, Peter

    2014-05-01

    A majority of streams in the Chesapeake Bay watershed have been rated as poor or very poor based on biological assessments. The Choptank River estuary, a Bay tributary on the eastern shore, is an example, where crop production in upland areas of the watershed contribute significant loads of nutrients to streams. We used a novel approach based on the relationship between the concentration of nitrate-N and the stable, water-soluble herbicide degradation product MESA {2-[2-ethyl-N-(1-methoxypropan-2-yl) -6-methylanilino]-2-oxoethanesulfonic acid} to distinguish between dilution and denitrification effects on the stream concentration of nitrate-N in agricultural subwatersheds. The ratio of mean nitrate-N concentration/(mean MESA concentration * 1000) for 15 subwatersheds was examined as a function of percent cropland on hydric soil. The observed inverse relationship (R2 = 0.65, p nitrate-N, but also the stream sampling bias of the croplands caused by extensive drainage ditch networks. MESA was also used to track nitrate-N fate within the estuary of the Choptank River. The relationship between nitrate-N and MESA concentrations in samples collected over three years was linear (0.95 ≤ R2 ≤ 0.99) for all eight sampling dates except one where R2 = 0.90. This very strong correlation indicates that nitrate-N was conserved in much of the Choptank River estuary, that dilution alone is responsible for the changes in nitrate-N and MESA concentrations, and more importantly nitrate-N loads are not reduced in the estuary prior to entering the Chesapeake Bay.

  7. Island Bay Wilderness study area : Island Bay National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a brief report on a wilderness study area located in the Island Bay National Wildlife Refuge. It discusses the history of the study area, its...

  8. Delineating incised stream sediment sources within a San Francisco Bay tributary basin

    OpenAIRE

    Bigelow, Paul; Benda, Lee; Pearce, Sarah

    2016-01-01

    Erosion and sedimentation pose ubiquitous problems for land and watershed managers, requiring delineation of sediment sources and sinks across landscapes. However, the technical complexity of many spatially explicit erosion models precludes their use by practitioners. To address this critical gap, we demonstrate a contemporary use of applied geomorphometry through a straightforward GIS analysis of sediment sources in the San Francisco Bay Area in California, USA, designed to support erosion r...

  9. Lavaca Bay 1985-1987

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Samples were collected from October 15, 1985 through June 12, 1987 in emergent marsh and non-vegetated habitats throughout the Lavaca Bay system to characterize...

  10. FL BAY SPECTROUT-DIET

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Juvenile spotted seatrout and other sportfish are being monitored annually over a 6-mo period in Florida Bay to assess their abundance over time relative to...

  11. Tšarterkool USA-s / Johannes Kiersch

    Index Scriptorium Estoniae

    Kiersch, Johannes

    2001-01-01

    24.-27. mainì 01 toimub Tallinnas EFFE 2001 (European Forum of Freedom in Education) konverents "Haridus tänases kodanikuühiskonnas." Konverentsil esineb ka Witteni Waldorf-pedagoogika Instituudi õppejõud Johannes Kiersch. Lähemalt tema artiklist USA-s populaarsust võitvate tsharterkoolide kohta, mis on riigi- ja erakooli vahevorm

  12. Tsunami Inundation modeling for Tolaga Bay, Tokomaru Bay, Hicks Bay and Te Araroa communities

    Science.gov (United States)

    Barberopoulou, A.; Wang, X.; Power, W. L.

    2012-12-01

    We assess the tsunami hazard to four communities in Raukumara Peninsula (Northeastern region of North Island of New Zealand): Tokomaru Bay, Tolaga Bay, Hicks Bay and Te Araroa. Representative severe but realistic scenarios that could affect the Raukumara peninsula are earthquakes that rupture the interface between the Australian and Pacific plates, earthquakes that rupture faults within the overlying Australian plate or the subducting Pacific plate (location is not always well constrained). Earthquakes that rupture both the plate interface and simultaneously faults within the crust of the Australian plate are also a possibility. Tsunamis may also be caused by submarine landslides that occur near the edge of the continental shelf, but these are not considered here. For this study four scenario events were constructed, including a distant event from South America (offshore Peru), outer rise events and a thrust event in the Hikurangi region off the east coast of New Zealand. The sources are not exhaustive but representative of the types of significant events that could occur in the region and were either improved from earlier sources or derived from recent studies. Available high resolution LiDAR and RTK data were combined with topographic and LINZ data for the development of bathymetric/topographic grids. Our modelling results show that Tolaga Bay appears most vulnerable to tsunami inundation although Hicks Bay and Te Araroa are also significantly inundated in several of the scenarios. Tokomaru Bay is naturally well protected because the rapid change in elevation limits the range of inundation. The worst scenario for Tokomaru Bay was an earthquake in the Hikurangi subduction zone resulting in large flow depths, whereas for Tolaga Bay inundation is severe from most scenarios. Hicks Bay and Te Araroa get the most severe flooding from earthquakes in South America and on the Hikurangi subduction zone. Inundation extent is similar for Tolaga Bay during the Outer Rise and

  13. An evaluation of a professional development course for secondary school science teachers: Chesapeake Watershed Ecology

    Science.gov (United States)

    Wood, Barbara Bonsall

    1997-12-01

    Concern about the quality of schools has grown to the point that it has become a national goal to improve education in the United States. Science education in particular has been under attack. Improvement requires not only changes in science content, but also in instructional approach. Implicit in this reform is an equally substantive change in professional development practice because too many science teachers are unprepared to meet these challenges. Unfortunately, courses to instruct secondary science teachers both in research techniques and instructional strategies are rare. Chesapeake Watershed Ecology, a professional development course, was created to meet this need. The course was evaluated within the framework of Stake's Countenance Model, using an objectives-based approach liberally embedded with qualitative methods. Research questions and findings focused on congruence between what was intended to occur and what was actually observed to occur before, during, and after instruction. Specifically, this formative study judged the effectiveness of the course at providing secondary science teachers with realistic research skills and strategies for the high school classroom. Research questions focused on 10 program features: teacher background, appropriate curriculum, resource availability, teacher participation, course choreography, classroom interactions, improved performance, teacher attitudes, intent of the teachers to use course activities in their own classrooms, and unexpected outcomes. Because nine of the ten features well exceeded criterion standards, the course was deemed effective and worthy of adoption. The findings of the evaluation led to four major implications beyond the course: (1) The Stake Model was an effective assessment tool that may be useful in other professional development course evaluations. (2) Chesapeake Watershed Ecology was an effective model for conceptual integration of scientific disciplines with pedagogical methods. (3

  14. Effects of waves on water dispersion in a semi-enclosed estuarine bay

    Science.gov (United States)

    Delpey, M. T.; Ardhuin, F.; Otheguy, P.

    2012-04-01

    The bay of Saint Jean de Luz - Ciboure is a touristic destination located in the south west of France on the Basque coast. This small bay is 1.5km wide for 1km long. It is semi-enclosed by breakwaters, so that the area is mostly protected from waves except in its eastern part, where wave breaking is regularly observed over a shallow rock shelf. In the rest of the area the currents are generally weak. The bay receives fresh water inflows from two rivers. During intense raining events, the rivers can introduce pollutants in the bay. The input of pollutants combined with the low level dynamic of the area can affect the water quality for several days. To study such a phenomenon, mechanisms of water dispersion in the bay are investigated. The present paper focuses on the effects of waves on bay dynamics. Several field experiments were conducted in the area, combining wave and current measurements from a set of ADCP and ADV, lagrangian difter experiments in the surfzone, salinity and temperature profile measurements. An analysis of this set of various data is provided. It reveals that the bay combines remarkable density stratification due to fresh water inflows and occasionally intense wave-induced currents in the surfzone. These currents have a strong influence on river plume dynamics when the sea state is energetic. Moreover, modifications of hydrodynamics in the bay passes are found to be remarkably correlated with sea state evolutions. This result suggests a significant impact of waves on the bay flushing. To further analyse these phenomena, a three dimensional numerical model of bay hydrodynamics is developed. The model aims at reproducing fresh water inflows combined with wind-, tide- and wave-induced currents and mixing. The model of the bay is implemented using the code MOHID , which has been modified to allow the three dimensional representation of wave-current interactions proposed by Ardhuin et al. [2008b] . The circulation is forced by the wave field modelled

  15. Go.USA.gov URL Shortner API

    Data.gov (United States)

    General Services Administration — The Go.USA.gov REST API allows you interact with Go.USA.gov by shortening URLs, previewing long urls, and getting the number of clicks to a Go.USA.gov URL.. An API...

  16. Euroopa teadis USA salavanglaist / Tõnis Erilaid

    Index Scriptorium Estoniae

    Erilaid, Tõnis, 1943-

    2005-01-01

    USA endise välisministri Colin Powelli sõnul pole see tema sõpradele Euroopas uudiseks, et USA on viinud vange riikidesse, kus tema seadused ei kehti. USA praeguse välisministri Condoleezza Rice'i sõnul on USA vange üle kuulanud väljaspool USA-d. USA Today kirjeldab Stare Kiejkuty küla Poolas, kus arvatavasti on olnud salavangla

  17. Understanding the Flushing Capability of Bellingham Bay and Its Implication on Bottom Water Hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Taiping; Yang, Zhaoqing

    2015-05-05

    In this study, an unstructured-grid finite-volume coastal ocean model (FVCOM) was used to simulate hydrodynamic circulation and assess the flushing capability in Bellingham Bay, Washington, USA. The model was reasonably calibrated against field observations for water level, velocity and salinity, and was further used to calculate residence time distributions in the study site. The model results suggest that, despite the large tidal ranges (~4 m during spring tide), tidal currents are relatively weak in Bellingham Bay with surface currents generally below 0.5 m/s. The local residence time in Bellingham Bay varies from to near zero to as long as 15 days, depending on the location and river flow condition. In general, Bellingham Bay is a well-flushed coastal embayment affected by freshwater discharge, tides, wind, and density-driven circulation. The basin-wide global residence time ranges from 5-7 days. The model results also provide useful information on possible causes of the emerging summertime hypoxia problem in the north central region of Bellingham Bay. It was concluded that the formation of the bottom hypoxic water should result from the increased consumption rate of oxygen in the bottom oceanic inflow with low dissolved oxygen by organic matters accumulated at the regions characterized with relatively long residence time in summer months.

  18. Understanding the flushing capability of Bellingham Bay and its implication on bottom water hypoxia

    Science.gov (United States)

    Wang, Taiping; Yang, Zhaoqing

    2015-11-01

    In this study, an unstructured-grid finite-volume coastal ocean model (FVCOM) was used to simulate hydrodynamic circulation and assess the flushing capability in Bellingham Bay, Washington, USA. The model was reasonably calibrated against field observations for water level, velocity and salinity, and was further used to calculate water residence time in the study site. The model results suggest that, despite the large tidal ranges (∼4 m during spring tide), tidal currents are relatively weak in Bellingham Bay with surface currents generally below 0.5 m/s. The local water residence time in Bellingham Bay varies from near zero to as long as 15 days, depending on the location and river flow conditions. In general, Bellingham Bay is a well-flushed coastal embayment affected by freshwater discharge, tides, wind, and density-driven circulation. The basin-wide global residence time ranges from 5 to 7 days. The model results also provide useful information on possible causes of the emerging summertime hypoxia problem in the north central region of Bellingham Bay. Model results suggest that the formation of hypoxia in bottom water results from an enhanced oxygen consumption rate in the oceanic bottom water inflow with low dissolved oxygen by organic matters accumulated at the regions characterized with relatively long residence time in summer months.

  19. Humboldt Bay, California Benthic Habitats 2009 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  20. Bayes linear statistics, theory & methods

    CERN Document Server

    Goldstein, Michael

    2007-01-01

    Bayesian methods combine information available from data with any prior information available from expert knowledge. The Bayes linear approach follows this path, offering a quantitative structure for expressing beliefs, and systematic methods for adjusting these beliefs, given observational data. The methodology differs from the full Bayesian methodology in that it establishes simpler approaches to belief specification and analysis based around expectation judgements. Bayes Linear Statistics presents an authoritative account of this approach, explaining the foundations, theory, methodology, and practicalities of this important field. The text provides a thorough coverage of Bayes linear analysis, from the development of the basic language to the collection of algebraic results needed for efficient implementation, with detailed practical examples. The book covers:The importance of partial prior specifications for complex problems where it is difficult to supply a meaningful full prior probability specification...

  1. With Prudhoe Bay in decline

    International Nuclear Information System (INIS)

    Almost every day, it seems, someone is mentioning Prudhoe Bay---its development activities, the direction of its oil production, and more recently its decline rate. Almost as frequently, someone is mentioning the number of companies abandoning exploration in Alaska. The state faces a double-edged dilemma: decline of its most important oil field and a diminished effort to find a replacement for the lost production. ARCO has seen the Prudhoe Bay decline coming for some time and has been planning for it. We have reduced staff, and ARCO and BP Exploration are finding cost-effective ways to work more closely together through such vehicles as shared services. At the same time, ARCO is continuing its high level of Alaskan exploration. This article will assess the future of Prudhoe Bay from a technical perspective, review ARCO's exploration plans for Alaska, and suggest what the state can do to encourage other companies to invest in this crucial producing region and exploratory frontier

  2. Community-level response of fishes and aquatic macroinvertebrates to stream restoration in a third-order tributary of the Potomac River, USA

    Science.gov (United States)

    Selego, S.M.; Rose, C.L.; Merovich, G.T., Jr.; Welsh, S.A.; Anderson, James T.

    2012-01-01

    Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010). Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI), the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions. Copyright ?? 2012 Stephen M. Selego et al.

  3. Community-Level Response of Fishes and Aquatic Macroinvertebrates to Stream Restoration in a Third-Order Tributary of the Potomac River, USA

    Directory of Open Access Journals (Sweden)

    Stephen M. Selego

    2012-01-01

    Full Text Available Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010. Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI, the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions.

  4. Sea-Level Rise Implications for Coastal Protection from Southern Mediterranean to the U.S.A. Atlantic Coast

    Science.gov (United States)

    Ismail, Nabil; Williams, Jeffress

    2013-04-01

    demonstrated in autumn 2010 when the storm Becky reached the Santander Bay, Spain. As reported by THESEUS, the FP-7 EU project (2009-2013), the peak of nearshore significant wave height was about 8 m, the storm surge reached 0.6 m, with tidal level of 90% of the tidal range. The latest storm in December 2010, which hit the Nile Delta and which was the severest in the last decades showed that generated surges, up to 1.0 m as well as a maximum of 7.5 m wave height in the offshore of Alexandria presented a major natural hazard in coastal zones in terms of wave run up and overtopping. Along the US Atlantic Coast, where Hurricane Sandy this autumn and Hurricane Irene in 2011 left chaos in their wakes, a perfect storm of rising sea levels and dense coastal development at high risk . Super storm Sandy sent a storm surge of 4-5 m onto New Jersey's and New York's fragile barrier island and urban shorelines, causing an estimated 70 billion (USD) in damages and widespread misery for coastal inhabitants. Sea Level Rise and Impact on Upgrade of Coastal Structures: Williams (2013) highlights in his recent paper that adaptation planning on national scales in the USA for projected sea-level rise of 0.5-2 m by A.D. 2100 is advisable. Further he points out that sea-level rise, as a major driving force of change for coastal regions, is becoming increasingly important as a hazard to humans and urban areas in the coastal zone worldwide as global climate change takes effect. During the 20th century, sea level began rising at a global average rate of 1.7 mm/yr (). The current average rise rate is 3.1 mm/yr, a 50% increase over the past two decades. Many regions are experiencing even greater rise rates due to local geophysical (e.g., Louisiana, Chesapeake Bay) and oceanographic (mid-Atlantic coast) forces. Further the Mississippi River Delta plain region of Louisiana has much higher than average rates of LRSL rise due to geologic factors such as subsidence and man-made alterations to the delta plain

  5. Distribution and behavior of major and trace elements in Tokyo Bay, Mutsu Bay and Funka Bay marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Teruyuki [Musashi Inst. of Technology, Atomic Energy Research Laboratory, Kawasaki, Kanagawa (Japan); Kimura, Ken-ichiro [Musashi Inst. of Technology, Graduate School, Research Division in Engineering, Kawasaki, Kanagawa (Japan)

    2003-06-01

    Fourteen major and trace elements in marine sediment core samples collected from the coasts along eastern Japan, i.e. Tokyo Bay (II) (the recess), Tokyo Bay (IV) (the mouth), Mutsu Bay and Funka Bay and the Northwest Pacific basin as a comparative subject were determined by the instrumental neutron activation analysis (INAA). The sedimentation rates and sedimentary ages were calculated for the coastal sediment cores by the {sup 210}Pb method. The results obtained in this study are summarized as follows: (1) Lanthanoid abundance patterns suggested that the major origin of the sediments was terrigenous material. La*/Lu* and Ce*/La* ratios revealed that the sediments from Tokyo Bay (II) and Mutsu Bay more directly reflected the contribution from river than those of other regions. In addition, the Th/Sc ratio indicated that the coastal sediments mainly originated in the materials from the volcanic island-arcs, Japanese islands, whereas those from the Northwest Pacific mainly from the continent. (2) The correlation between the Ce/U and Th/U ratios with high correlation coefficients of 0.920 to 0.991 indicated that all the sediments from Tokyo Bay (II) and Funka Bay were in reducing conditions while at least the upper sediments from Tokyo Bay (IV) and Mutsu Bay were in oxidizing conditions. (3) It became quite obvious that the sedimentation mechanism and the sedimentation environment at Tokyo Bay (II) was different from those at Tokyo Bay (IV), since the sedimentation rate at Tokyo Bay (II) was approximately twice as large as that at Tokyo Bay (IV). The sedimentary age of the 5th layer (8{approx}10 cm in depth) from Funka Bay was calculated at approximately 1940{approx}50, which agreed with the time, 1943{approx}45 when Showa-shinzan was formed by the eruption of the Usu volcano. (author)

  6. USA-s valmib Eesti reisisaadete sari / Maris Meiessaar

    Index Scriptorium Estoniae

    Meiessaar, Maris

    2009-01-01

    Eesti juurtega ameerika filmimees James Tusty oma dokfilmi "Laulev revolutsioon" sünnist ja retseptsioonist. Praegu valmistub ta koos Allfilmiga Euroopa telekanalite jaoks tegema filmi sellesuvisest laulupeost ning USA televisiooni jaoks 13-osalist sarja "Estonia"

  7. Pepeljajev eesti näitlejatega USA-s

    Index Scriptorium Estoniae

    2008-01-01

    Sasha Pepeljajevi tantsulavastust "Uksed" etendati USA rahvusvahelisel teatrifestivalil "Arts & Ideas". Vene-Eesti trupi Apparatus lavastus on pühendatud Daniil Harmsi 100. sünniaastapäevale ning põhineb tema töödel

  8. Future USA development

    International Nuclear Information System (INIS)

    The planning for further development in the USA at this time is a mixture of expectation and guessing. Modeling development is certain to continue, but the target reactor is uncertain. The next plant may or may not use the FFTR driver fuel design. The planning, therefore, emphasizes fundamentals and flexibility. There are many options to be modeled. The FFTF driver fuel performance in FFTF must be evaluated; both the reference and improved designs. A decision to use the FFTR driver design in the large plant will demand predictions on the effects of axial blankets, constant power (rather than decreasing) throughout life, and power changes, behavior beyond breach and design basis transients in large plants. A decision favoring a lower doubling time oxide design adds the effects of higher strength/lower swelling alloys, increased pin diameter, reduced cladding thickness/diameter, increased smeared density, gap versus pellet density, and reduced pin pitch/diameter. A helium bonded carbide design adds concern about increased potential for fuel-cladding-assembly mechanical interactions. And blanket pin performance predictions, either in a homogeneous or a heterogeneous core, add an increasing power history and enhanced assembly interactions. It is possible that the decision will be to choose a first core and retain all options for later cores. The modeling objective, for whatever options are chosen, is to predict the effect of normal and off-normal design conditions on performance limits (i.e., fuel temperature, pin deformation, pin lifetime). Several significant uncertainties in the mechanisms associated with the performance limits remain and will be addressed. These include gap closure, gap conductance and fuel properties at higher burnup, fuel-fission product reactions, retained gas, breach mechanisms, assembly interactions and behavior beyond breach, plus establishing appropriate criteria. The LIFE system, with its elements of 1D and 2D fundamental modeling

  9. Dengue in Florida (USA

    Directory of Open Access Journals (Sweden)

    Jorge R. Rey

    2014-12-01

    Full Text Available Florida (USA, particularly the southern portion of the State, is in a precarious situation concerning arboviral diseases. The geographic location, climate, lifestyle, and the volume of travel and commerce are all conducive to arbovirus transmission. During the last decades, imported dengue cases have been regularly recorded in Florida, and the recent re-emergence of dengue as a major public health concern in the Americas has been accompanied by a steady increase in the number of imported cases. In 2009, there were 28 cases of locally transmitted dengue in Key West, and in 2010, 65 cases were reported. Local transmission was also reported in Martin County in 2013 (29 cases, and isolated locally transmitted cases were also reported from other counties in the last five years. Dengue control and prevention in the future will require close cooperation between mosquito control and public health agencies, citizens, community and government agencies, and medical professionals to reduce populations of the vectors and to condition citizens and visitors to take personal protection measures that minimize bites by infected mosquitoes.

  10. Backscatter imagery in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1x1 meter resolution backscatter mosaic of Jobos Bay, Puerto Rico (in NAD83 UTM 19 North). The backscatter values are in relative 8-bit (0 –...

  11. USA pelgab Hiina tehnoloogialuuret / Tõnis Arnover

    Index Scriptorium Estoniae

    Arnover, Tõnis, 1952-

    2005-01-01

    Hiina Ameerika-vastasest majandusluurest. USA luureameti andmetel on USA-s loodud üle kolme tuhande Hiina firma, kelle ülesandeks on tööstusliku või sõjalise tehnoloogia hankimine. Vt. samas: Hiina firmad ostavad üha suuremaid USA ettevõtteid

  12. Kohtusid Eesti ja USA presidendid

    Index Scriptorium Estoniae

    2007-01-01

    25. juunil 2007 kohtusid Washingtonis Valges Majas USA president George W. Bush ja Eesti president Toomas Hendrik Ilves. Kõne all oli viisavabadus, arengud Afganistanis ja Iraagis, NATO küberkaitsekeskuse loomine Tallinna. T.H. Ilves kohtus ka USA Kongressi Esindajatekoja spiikri Nancy Pelosi, kaitseminister Robert Gates'i ja parlamendiliikmetega. Vabariigi President töövisiidil Ameerika Ühendriikides 25.-26.06.2007

  13. δ15N as a proxy for historic anthropogenic nitrogen loading in Charleston Harbor, SC, USA

    Science.gov (United States)

    Payne, T. N.; Andrus, C. F. T.

    2015-12-01

    Bivalve shell geochemistry can serve as a useful indicator of changes in coastal environments. There is increasing interest in developing paleoenvironmental proxies from mollusk shell organic components. Numerous studies have focused on how the δ15N obtained from bivalve tissues can be used to trace present-day wastewater input into estuaries. However, comparatively little attention has been paid to tracing the impact of anthropogenic nitrogen loading into estuaries over time. By measuring historic levels of δ15N in the organic fraction of oyster shells (Crassostrea virginica) from archaeological sites around Charleston Harbor and comparing those levels to the δ15N content of modern shells, it is possible to assess how nitrogen has fluctuated historically in the area. Whole-shell samples from the Late Archaic Period (~3000-4000 BP, Late Woodland Period (~1400-800 BP), 18th and 19th centuries, and modern controls were measured for %N and d15N. Evidence of increased anthropogenic input of N is expected to begin in the early historic period based on similar analysis in Chesapeake Bay. More ancient samples may give insight into baseline conditions prior to recent population growth and industrialization. This information could help understand how large-scale anthropogenic nitrogen loading has affected coastal ecosystems over time and guide future remediation. Furthermore, this project will help refine and improve this novel proxy of past environmental conditions.

  14. Reprocessing (1): Barnwell, USA

    International Nuclear Information System (INIS)

    The matter discussed is whether the US Administration will allow a large reprocessing plant, located in a South Carolina forest, to start operations. Constructed by private industry at a cost so far of some 250 million dollars, this facility could become either a key component in the US nuclear power programme, or a massively expensive white elephant. Designed as the first full-scale commercial plant to reprocess spent fuel from power reactors, the facility is falling victim to rising concerns about the proliferation of nuclear weapons, and its fate will probably hang on a complex series of regulatory, political and diplomatic decisions expected to be taken in the near future. Even if the Administration decides to allow the plant to start operations, however, its problems will not be entirely over. Before it can operate at full capacity additional facilities to solidify highly active wastes from the plant and to convert Pu nitrate to oxide will be required, estimated to cost 500 million dollars, a sum that private industry says it is unwilling to risk without government assistance. The plant is designed to reprocess fuel continuously from about 50 commercial power reactors, extracting Pu and U and recycling the materials as new reactor fuel. Activities of environmental and anti-nuclear groups with regard to large scale Pu production are discussed, together with the findings of the US Nuclear Regulatory Commission, including the holding of public hearings. Political developments are also discussed, including the establishment of international controls. The conclusion is reached that the future for reprocessing in the USA is uncertain. (U.K.)

  15. Nelson River and Hudson Bay

    Science.gov (United States)

    2002-01-01

    Rivers that empty into large bodies of water can have a significant impact on the thawing of nearshore winter ice. This true-color Moderate Resolution Imaging Spectroradiometer (MODIS) image from May 18, 2001, shows the Nelson River emptying spring runoff from the Manitoba province to the south into the southwestern corner of Canada's Hudson Bay. The warmer waters from more southern latitudes hasten melting of ice near the shore, though some still remained, perhaps because in shallow coastal waters, the ice could have been anchored to the bottom. High volumes of sediment in the runoff turned the inflow brown, and the rim of the retreating ice has taken on a dirty appearance even far to the east of the river's entrance into the Bay. The sediment would have further hastened the melting of the ice because its darker color would have absorbed more solar radiation than cleaner, whiter ice. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  16. Simulation of Pollutant Transport in Marmaris Bay

    Institute of Scientific and Technical Information of China (English)

    Lale BALAS

    2001-01-01

    The circulation pattern and the pollutant transport in the Marmaris Bay are simulated by the developed three-dimensional baroclinic model. The Marmaris Bay is located at the Mediterranean Sea coast of Turkey. Since the sp ring tidal range is typically 20~30 cm, the dominant forcing for the circulation and water exchange is due to the wind action. In the Marmaris Bay, there is sea outfall discharging directly into the bay, and that threats the bay water quality significantly. The current patterns in the vicinity of the outfall have been observed by tracking drogues which are moved by currents at different water depths. In the simulations of pollutant transport, the coliforms-counts is used as the tracer.The model provides realistic predictions for the circulation and pollutant transport in the Marmaris Bay. The transport model component predictions well agree with the results of a laboratory model study.

  17. Hydrodynamic numerical modelling of Maputo Bay

    OpenAIRE

    Canhanga, S.J.V.

    2003-01-01

    The aim of this work was to understand by using a numerical model, the main characteristics of the Maputo Bay hydrodynamics; and furthermore to assess the hydrodynamics implications on the different processes that can occur in the Bay. The study was initiated with a description of the hydrodynamical characteristics of Maputo Bay, through the analysis of vertical profiles of salinity and temperature, time series of the components of tide currents and water elevation. The wind intensity and ...

  18. 77 FR 70891 - Safety Zone; Bay Bridge Construction, San Francisco Bay, San Francisco, CA

    Science.gov (United States)

    2012-11-28

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bay Bridge Construction, San Francisco Bay..., CA in support of the Bay Bridge Construction Safety Zone from November 1, 2012 through July 31, 2013...: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of...

  19. Remote Sensing as a Tool to Track Algal Blooms in the Great Salt Lake, Utah, USA

    Science.gov (United States)

    Bradt, S. R.; Wurtsbaugh, W. A.; Naftz, D.; Moore, T.; Haney, J.

    2006-12-01

    The Great Salt Lake is a large hypersaline, terminal water body in northern Utah, USA. The lake has both a significant economic importance to the local community as a source of brine shrimp and mineral resources, as well as, an ecological importance to large numbers of migratory waterfowl. Due to nutrient input from sewage treatment plants, sections of the Great Salt Lake are subjected to highly eutrophic conditions. One of the main tributaries, Farmington Bay, experiences massive blooms of cyanobacteria which can reach concentrations in excess of 300 mg l-1 in the bay. Effects of these blooms can be observed stretching into the rest of the lake. The detrimental outcomes of the blooms include unsightly scums, foul odor and the danger of cyanobacterial toxins. While the blooms have an obvious effect on Farmington Bay, it is quite possible that the cyanobacteria impact a much wider area of the lake as currents move eutrophic water masses. Of particular interest is the reaction of brine shrimp to the plumes of cyanobacteria-rich water leaving Farmington Bay. We are employing remote sensing as a tool to map the distribution of algae throughout the lake and produce lake-wide maps of water quality on a regular basis. On-lake reflectance measurements have been coupled with MODIS satellite imagery to produce a time series of maps illustrating changes in algal distribution. The successes and shortcomings of our remote sensing technique will be a central topic of this presentation.

  20. Upper ocean stratification and circulation in the northern Bay of Bengal during southwest monsoon of 1991

    Digital Repository Service at National Institute of Oceanography (India)

    Gopalakrishna, V.V.; Murty, V.S.N.; Sengupta, D.; Shenoy, Shrikant; Araligidad, N.

    by CMMACS, Bangalore (site giveninthetext).ThisistheNIOcontributionNo. 3698. References Babu, M.T., Prasanna Kumar, S., Rao, D.P., 1991. A sub- surface cyclonic eddy in the Bay of Bengal. Journal of Marine Research 49, 403–410. Fong, D.A., Geyer, W.R., 2001....PaperNo.13,USGovernmentPrintingOffice, 173pp. Levitus,S.,Boyer,Y.P.,1994.WorldOceanAtlas,1994,Vol.4, Temperature, NOAA Atlas NESDIS, 4 US Dept of Commerce, Washington, USA, 117pp. Murty, V.S.N., Sarma, Y.V.B., Rao, D.P., Murty, C.S., 1992a. Water...

  1. The Impact of Competition on Raising Mathematics Competency at Camelot Elementary School in Chesapeake, Virginia

    Science.gov (United States)

    Hayden, L. B.; Johnson, D.

    2012-12-01

    In 1995, the Virginia Department of Education approved a federal mandate for No Child Left Behind 2001 Education Act implementing the Standards of Learning (SOL) in four content areas: Mathematics, Science, English, and History and Social Sciences. These new guidelines set forth learning and achievement expectations for content areas for grades K-12 in Virginia's Public Schools. Given the SOL mandates, Virginia's elementary teachers and school leaders utilized research for specific teaching methods intended to encourage score improvements on end of year mathematics tests. In 2001, the concept of the Math Sprint Competition was introduced to Camelot Elementary School in Chesapeake Virginia, by researchers at Elizabeth City State University of Elizabeth City, North Carolina. Camelot Elementary, a K-5 school, is a Title I school nestled in a lower middle class neighborhood and houses a high number of minority students. On average, these students achieve lower test score gains than students in higher socioeconomic status district schools. Defined as a test-review based in relay format that utilizes released SOL test items, Math Sprint promotes mathematical skills outlined in Virginia SOL's and encourages competition among students that motivated them to quickly pick up on new material and retain the old material in order to out-do the others. Research identified was based on specific relationships between student competition and statewide testing results in mathematics for grades three, four, and five at Camelot Elementary. Data was compiled from results of the Math Sprint Competition and research focused on methods for motivating students encouraged by the use of a math sprint competition. Individual Pearson Product Moment Correlations were conducted to determine which variables possess strong and statistically significant relationships. Significantly, positive results came from 2005 to 2010 math sprints data from which students participated.

  2. USA asekaitseminister seisab Eesti eest

    Index Scriptorium Estoniae

    2010-01-01

    Eestis visiidil viibiv USA asekaitseminister poliitika alal Michele Flournoy ütles, et pooldab koostöökohtade otsimist Moskvaga, kuid on kindlal seisukohal, et Venemaa ei tohi end siin piirkonnas kehtestada. Flournoy tunnustas Eesti panust Afganistani ning samuti liitlassuhetesse laiemalt

  3. Dyslexia Laws in the USA

    Science.gov (United States)

    Youman, Martha; Mather, Nancy

    2013-01-01

    Throughout the various states of the USA, the appropriate identification of dyslexia and the timely provision of interventions are characterized by variability and inconsistency. Several states have recognized the existence of this disorder and the well-established need for services. These states have taken proactive steps to implement laws and…

  4. USA panustab keskkonda / Jeffrey Goldstein

    Index Scriptorium Estoniae

    Goldstein, Jeffrey

    2007-01-01

    USA uus energiapoliitika kava näeb ette bensiini tarbimise vähendamist järgneva 10 aasta jooksul 20%, mis omakorda vähendab ameeriklaste autodest eralduva süsihappegaasi heitmete kasvu ning vähendab sõltuvust naftast

  5. Sõda, mille USA on juba kaotanud / Mart Helme

    Index Scriptorium Estoniae

    Helme, Mart, 1949-

    2003-01-01

    USA pole suutnud Iraagi-vastase sõja vajalikkust põhjendada, arvavad paljud USA poliitikavaatlejad. Rängaks diplomaatiliseks eksimuseks peetakse USA kaitseministri Donald Rumsfeldi avaldust, et USA ei vaja kellegi abi sõjas

  6. USA andis Gruusiale vastakaid signaale / Neeme Raud

    Index Scriptorium Estoniae

    Raud, Neeme, 1969-

    2008-01-01

    USA välisministri Condoleezza Riceþi saabumisest Thbilisisse, et avaldada Gruusiale toetust. USA poolt antud soovitustest Gruusia president Mihhail Saakashvilile mitte jõudu kasutada ega alluda Venemaa provokatsioonidele ning hoiatustest sõjalise konflikti tagajärgede eest. USA analüütikute arvamusi

  7. USA suursaadikuga Tallinna lahel / Katrin Kruss

    Index Scriptorium Estoniae

    Kruss, Katrin

    2007-01-01

    USA suursaadik Stanley Davis Phillips oma haridusteest, perekonnast, armastusest mere vastu, panusest isa Earl Phillipsi mööbliäri laiendamisse, golfiharrastusest, suursaadikute ettevalmistusest USA-s, suursaadiku residentsist Pirital ning uue saatkonnahoone otsingutest Tallinnas. Lisa: Stanley Davis Phillips

  8. Using social network analysis tools in ecology : Markov process transition models applied to the seasonal trophic network dynamics of the Chesapeake Bay

    NARCIS (Netherlands)

    Johnson, Jeffrey C.; Luczkovich, Joseph J.; Borgatti, Stephen P.; Snijders, Tom A. B.; Luczkovich, S.P.

    2009-01-01

    Ecosystem components interact in complex ways and change over time due to a variety of both internal and external influences (climate change, season cycles, human impacts). Such processes need to be modeled dynamically using appropriate statistical methods for assessing change in network structure.

  9. A Landscape Indicator Approach to the Identification and Articulation of the Ecological Consequences of Land Cover Change in the Chesapeake Bay Watershed, 1970-2000

    Science.gov (United States)

    Slonecker, Terrence

    2008-01-01

    The advancement of geographic science in the area of land surface status and trends and land cover change is at the core of the current geographic scientific research of the U.S. Geological Survey (USGS) (McMahon and others, 2005). Perhaps the least developed or articulated aspects of USGS land change science have been the identification and analysis of the ecological consequences of land cover change. Changes in land use and land cover significantly affect the ability of ecosystems to provide essential ecological goods and services, which, in turn, affect the economic, public health, and social benefits that these ecosystems provide. One of the great scientific challenges for geographic science is to understand and calibrate the effects of land use and land cover change and the complex interaction between human and biotic systems at a variety of natural, geographic, and political scales. Understanding the dynamics of land surface change requires an increased understanding of the complex nature of human-environmental systems and will require a suite of scientific tools that include traditional geographic data and analysis methods, such as remote sensing and geographic information systems (GIS), as well as innovative approaches to understanding the dynamics of complex systems. One such approach that has gained much recent scientific attention is the landscape indicator, or landscape assessment, approach, which has been developed with the emergence of the science of landscape ecology.

  10. Zooplankton and other data collected from PURITAN and other platforms in CHesapeake Bay and other Seas from 08 June 1985 to 31 March 1988 (NODC Accession 8800234)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — PLEASE NOTE there is discrepancy between the content of actual data in this accession and the abstract information that was present in Thaila folder for this...

  11. 33 CFR 334.200 - Chesapeake Bay, Point Lookout to Cedar Point; aerial and surface firing range and target area, U...

    Science.gov (United States)

    2010-07-01

    ... damage caused by projectiles, bombs, missiles, or Naval or Coast Guard vessels to fishing structures or... and bombs will be dropped at frequent intervals in the target areas. Hooper and Hannibal target...

  12. CASE STUDY APPLICATION OF THE BASINS CLIMATE ASSESSMENT TOOL, AND DEVELOPMENT OF A FRAMEWORK FOR ASSESSING CLIMATE CHANGE IMPACTS ON WATER QUALITY IN THE CHESAPEAKE BAY WATERSHED

    Science.gov (United States)

    Much of the U.S. is likely to experience warming temperatures and changes in precipitation amount and/or intensity during the next century. Water resources are highly vulnerable to these changes, with possible effects including increased occurrence of floods and droughts, and wa...

  13. NOAA Office for Coastal Management Coastal Inundation Digital Elevation Model: Baltimore/Washington Weather Forecast Office (LWX WFO) - Maryland (West of Chesapeake Bay)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data were created as part of the National Oceanic and Atmospheric Administration Office for Coastal Management's efforts to create an online mapping viewer...

  14. 2004 Sediment Profile Imaging (SPI) Data for Catlett and Goodwin Islands on the York River, Chesapeake Bay, Virginia (Ches_2004SPI)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the sediment profile imaging data from 2004 (79 stations).In Fall/Winter 2002, researchers from the Virginia Institute of Marine Science...

  15. Building the city with emphasis on urban mobility – examples from USA

    Directory of Open Access Journals (Sweden)

    Mojca Šašek Divjak

    2002-01-01

    Full Text Available In the last decades developed countries have tried to improve and strengthen public transport modes in urban regions, because they have established negative effects of car traffic on mobility: bottlenecks, increased investment in road infrastructure. New movements that have emerged in the nineties in USA, often coined as smart growth, emphasise efficient urban growth, which should be tied to public transport enabling rational prices of infrastructure and better spatial use. Good examples of such developments are shown, such as the San Francisco Bay area (California, Portland (Oregon and Salt Lake (Utah.

  16. Quantum Annealing for Variational Bayes Inference

    OpenAIRE

    Sato, Issei; Kurihara, Kenichi; Tanaka, Shu; Nakagawa, Hiroshi; Miyashita, Seiji

    2014-01-01

    This paper presents studies on a deterministic annealing algorithm based on quantum annealing for variational Bayes (QAVB) inference, which can be seen as an extension of the simulated annealing for variational Bayes (SAVB) inference. QAVB is as easy as SAVB to implement. Experiments revealed QAVB finds a better local optimum than SAVB in terms of the variational free energy in latent Dirichlet allocation (LDA).

  17. Safety culture development at Daya Bay NPP

    International Nuclear Information System (INIS)

    From view on Organization Behavior theory, the concept, development and affecting factors of safety culture are introduced. The focuses are on the establishment, development and management practice for safety culture at Daya Bay NPP. A strong safety culture, also demonstrated, has contributed greatly to improving performance at Daya Bay

  18. Towards a sustainable future in Hudson Bay

    International Nuclear Information System (INIS)

    To date, ca $40-50 billion has been invested in or committed to hydroelectric development on the rivers feeding Hudson Bay. In addition, billions more have been invested in land uses such as forestry and mining within the Hudson Bay drainage basin. However, there has never been a study of the possible impacts on Hudson Bay resulting from this activity. Neither has there been any federal environmental assessment on any of the economic developments that affect Hudson Bay. To fill this gap in knowledge, the Hudson Bay Program was established. The program will not conduct scientific field research but will rather scan the published literature and consult with leading experts in an effort to identify biophysical factors that are likely to be significantly affected by the cumulative influence of hydroelectric and other developments within and outside the region. An annotated bibliography on Hudson Bay has been completed and used to prepare a science overview paper, which will be circulated for comment, revised, and used as the basis for a workshop on cumulative effects in Hudson Bay. Papers will then be commissioned for a second workshop to be held in fall 1993. A unique feature of the program is its integration of traditional ecological knowledge among the Inuit and Cree communities around Hudson Bay with the scientific approach to cumulative impact assessment. One goal of the program is to help these communities bring forward their knowledge in such a way that it can be integrated into the cumulative effects assessment

  19. Guangdong Daya Bay nuclear power station project

    International Nuclear Information System (INIS)

    Daya Bay Nuclear Power Station is the largest joint-venture project which is also the largest commercial nuclear power plant currently under construction in China mainland. Organized and executed strictly in accordance with international standards, the Daya Bay project is seen as the first step taken by China in the development programme of large-capacity commercial nuclear power units

  20. Anthropization in Montevideo Bay during the Holocene

    International Nuclear Information System (INIS)

    This work is about the anthropogenic historic impacts in subtidal environments in Montevideo Bay. The studies carried out in the sediments enable to conclude that the increase of the industrial discharges (nutrients, heavy metals) are the cause of the chemical changes in the sediment of the Montevideo Bay

  1. Bayes Estimation of Queue Length

    Czech Academy of Sciences Publication Activity Database

    Dohnal, Pavel

    Praha : ÚTIA AV ČR, 2006 - ( And rýsek, J.), s. 1-8 [International PhD Workshop on Interplay of Societal and Technical Decision-Making, Young Generation Viewpoint /7./. Hrubá Skála (CZ), 25.09.2006-30.09.2006] R&D Projects: GA MŠk 1M0572; GA AV ČR 1ET100750401 Institutional research plan: CEZ:AV0Z10750506 Keywords : Bayes estimation * queue length * traffic flow * occupancy * intensity Subject RIV: BC - Control Systems Theory

  2. Reducing methylmercury accumulation in the food webs of San Francisco Bay and its local watersheds

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.A., E-mail: jay@sfei.org [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Looker, R.E. [San Francisco Bay Regional Water Quality Control Board, 1515 Clay Street, Suite 1400, Oakland, CA 94612 (United States); Yee, D. [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Marvin-Di Pasquale, M. [U.S. Geological Survey, Water Resources Division/MS 480, 345 Middlefield Road, Menlo Park, CA 94025 (United States); Grenier, J.L. [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Austin, C.M. [San Francisco Bay Regional Water Quality Control Board, 1515 Clay Street, Suite 1400, Oakland, CA 94612 (United States); McKee, L.J.; Greenfield, B.K. [San Francisco Estuary Institute, 4911 Central Avenue, Richmond, CA 94804 (United States); Brodberg, R. [California Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, 1001 I Street, Sacramento, CA 95812 (United States); Blum, J.D. [Department of Geological Sciences, University of Michigan, 1100 North University Avenue, Ann Arbor, MI 48109 (United States)

    2012-11-15

    San Francisco Bay (California, USA) and its local watersheds present an interesting case study in estuarine mercury (Hg) contamination. This review focuses on the most promising avenues for attempting to reduce methylmercury (MeHg) contamination in Bay Area aquatic food webs and identifying the scientific information that is most urgently needed to support these efforts. Concern for human exposure to MeHg in the region has led to advisories for consumption of sport fish. Striped bass from the Bay have the highest average Hg concentration measured for this species in USA estuaries, and this degree of contamination has been constant for the past 40 years. Similarly, largemouth bass in some Bay Area reservoirs have some of the highest Hg concentrations observed in the entire US. Bay Area wildlife, particularly birds, face potential impacts to reproduction based on Hg concentrations in the tissues of several Bay species. Source control of Hg is one of the primary possible approaches for reducing MeHg accumulation in Bay Area aquatic food webs. Recent findings (particularly Hg isotope measurements) indicate that the decades-long residence time of particle-associated Hg in the Bay is sufficient to allow significant conversion of even the insoluble forms of Hg into MeHg. Past inputs have been thoroughly mixed throughout this shallow and dynamic estuary. The large pool of Hg already present in the ecosystem dominates the fraction converted to MeHg and accumulating in the food web. Consequently, decreasing external Hg inputs can be expected to reduce MeHg in the food web, but it will likely take many decades to centuries before those reductions are achieved. Extensive efforts to reduce loads from the largest Hg mining source (the historic New Almaden mining district) are underway. Hg is spread widely across the urban landscape, but there are a number of key sources, source areas, and pathways that provide opportunities to capture larger quantities of Hg and reduce loads

  3. Reducing methylmercury accumulation in the food webs of San Francisco Bay and its local watersheds

    International Nuclear Information System (INIS)

    San Francisco Bay (California, USA) and its local watersheds present an interesting case study in estuarine mercury (Hg) contamination. This review focuses on the most promising avenues for attempting to reduce methylmercury (MeHg) contamination in Bay Area aquatic food webs and identifying the scientific information that is most urgently needed to support these efforts. Concern for human exposure to MeHg in the region has led to advisories for consumption of sport fish. Striped bass from the Bay have the highest average Hg concentration measured for this species in USA estuaries, and this degree of contamination has been constant for the past 40 years. Similarly, largemouth bass in some Bay Area reservoirs have some of the highest Hg concentrations observed in the entire US. Bay Area wildlife, particularly birds, face potential impacts to reproduction based on Hg concentrations in the tissues of several Bay species. Source control of Hg is one of the primary possible approaches for reducing MeHg accumulation in Bay Area aquatic food webs. Recent findings (particularly Hg isotope measurements) indicate that the decades-long residence time of particle-associated Hg in the Bay is sufficient to allow significant conversion of even the insoluble forms of Hg into MeHg. Past inputs have been thoroughly mixed throughout this shallow and dynamic estuary. The large pool of Hg already present in the ecosystem dominates the fraction converted to MeHg and accumulating in the food web. Consequently, decreasing external Hg inputs can be expected to reduce MeHg in the food web, but it will likely take many decades to centuries before those reductions are achieved. Extensive efforts to reduce loads from the largest Hg mining source (the historic New Almaden mining district) are underway. Hg is spread widely across the urban landscape, but there are a number of key sources, source areas, and pathways that provide opportunities to capture larger quantities of Hg and reduce loads

  4. Measuring the Carolina Bays Using Archetype Template Overlays on the Google Earth Virtual Globe; Planform Metrics for 25,000 Bays Extracted from LiDAR and Satellite Imagery

    Science.gov (United States)

    Davias, M. E.; Gilbride, J. L.

    2011-12-01

    Aerial photographs of Carolina bays taken in the 1930's sparked the initial research into their geomorphology. Satellite Imagery available today through the Google Earth Virtual Globe facility expands the regions available for interrogation, but reveal only part of their unique planforms. Digital Elevation Maps (DEMs), using Light Detection And Ranging (LiDAR) remote sensing data, accentuate the visual presentation of these aligned ovoid shallow basins by emphasizing their robust circumpheral rims. To support a geospatial survey of Carolina bay landforms in the continental USA, 400,000 km2 of hsv-shaded DEMs were created as KML-JPEG tile sets. A majority of these DEMs were generated with LiDAR-derived data. We demonstrate the tile generation process and their integration into Google Earth, where the DEMs augment available photographic imagery for the visualization of bay planforms. While the generic Carolina bay planform is considered oval, we document subtle regional variations. Using a small set of empirically derived planform shapes, we created corresponding Google Earth overlay templates. We demonstrate the analysis of an individual Carolina bay by placing an appropriate overlay onto the virtually globe, then orientating, sizing and rotating it by edit handles such that it satisfactorily represents the bay's rim. The resulting overlay data element is extracted from Google Earth's object directory and programmatically processed to generate metrics such as geographic location, elevation, major and minor axis and inferred orientation. Utilizing a virtual globe facility for data capture may result in higher quality data compared to methods that reference flat maps, where geospatial shape and orientation of the bays could be skewed and distorted in the orthographic projection process. Using the methodology described, we have measured over 25k distinct Carolina bays. We discuss the Google Fusion geospatial data repository facility, through which these data have been

  5. Bayes reconstruction of missing teeth

    DEFF Research Database (Denmark)

    Sporring, Jon; Jensen, Katrine Hommelhoff

    2008-01-01

     We propose a method for restoring the surface of tooth crowns in a 3D model of a human denture, so that the pose and anatomical features of the tooth will work well for chewing. This is achieved by including information about the position and anatomy of the other teeth in the mouth. Our system...... contains two major parts: A statistical model of a selection of tooth shapes and a reconstruction of missing data. We use a training set consisting of 3D scans of dental cast models obtained with a laser scanner, and we have build a model of the shape variability of the teeth, their neighbors, and their...... regularization of the log-likelihood estimate based on differential geometrical properties of teeth surfaces, and we show general conditions under which this may be considered a Bayes prior.Finally we use Bayes method to propose the reconstruction of missing data, for e.g. finding the most probable shape of a...

  6. Radioactivity Levels in Kola Bay

    International Nuclear Information System (INIS)

    Sediment samples were collected in May 1995 from 16 locations in Kola Bay, North-west Russia, during an expedition starting from Murmansk and ending at Kildin Island in the Barents Sea. The purpose was to study the contamination level in an area with several potential sources of civilian and military radioactive pollution. 137Cs concentrations in the sediments, algae and benthic samples were low, but small particles containing 137Cs were separated from the sediment samples. All the sediments between the nuclear icebreaker base Atomflot and the open Barents Sea contained 60Co. Traces of 125Sb, 134Cs, 95Zr, 154Eu and 152Eu were also detected in some of the samples. Plutonium levels were low, but the increased 238Pu/239,240Pu ratio at Atomflot indicated a fresh release from the facility or from the waste storage vessels, Lepse and Imandra, lying in front of it. An increased 238Pu/239,240Pu ratio was also found in sediment collected in the outlet of Kola Bay in the Barents Sea. (author)

  7. Sediment denitrifier community composition and nirS gene expression investigated with functional gene microarrays

    DEFF Research Database (Denmark)

    Francis, C.A.; Jackson, G.A.; Ward, B.B.; Bülow, Steffen

    2008-01-01

    A functional gene microarray was used to investigate denitrifier community composition and nitrite reductase (nirS) gene expression in sediments along the estuarine gradient in Chesapeake Bay, USA. The nirS oligonucleotide probe set was designed to represent a sequence database containing 539...... Chesapeake Bay clones, as well as sequences from many other environments. Greatest nirS diversity was detected at the freshwater station at the head of the bay and least diversity at the higher salinity station near the mouth of the Bay. The most common OTUs from the sequence database were detected on the......RNA level. These results suggest that the most actively denitrifying groups are responsible for most nirS expression as well Udgivelsesdato: 2008/11...

  8. Wastewater and Saltwater: Studying the Biogeochemistry and Microbial Activity Associated with Wastewater Inputs to San Francisco Bay

    Science.gov (United States)

    Challenor, T.; Menendez, A. D.; Damashek, J.; Francis, C. A.; Casciotti, K. L.

    2014-12-01

    to estuarine sediment found at other sites in the San Francisco Bay as well as the Chesapeake Bay, China East Sea, and Pearl River Estuary. Our data provide evidence for the path that N takes once entering the estuary and also further characterize the behavior of nitrifying microorganisms in extremely high-nutrient aquatic environments.

  9. Reconnaissance survey of nonpoint source pesticides in Maryland surface waters

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — As part of the Chesapeake Bay Agreement, the "Maryland Toxics Reduction Strategy for the Chesapeake Bay and its Tributaries" committed the State to identify the...

  10. The monterey bay broadband ocean bottom seismic observatory

    Directory of Open Access Journals (Sweden)

    R. Uhrhammer

    2006-06-01

    Full Text Available We report on the installation of a long-term buried ocean-floor broadband seismic station (MOBB in Monterey Bay, California (USA, 40km off-shore, at a water depth of 1000 m. The station was installed in April 2002 using a ship and ROV, in a collaborative effort between the Monterey Bay Aquarium Research Institute (MBARI and the Berkeley Seismological Laboratory (BSL. The station is located on the western side of the San Gregorio Fault, a major fault in the San Andreas plate boundary fault system. In addition to a 3-component CMG-1T seismometer package, the station comprises a current meter and Differential Pressure Gauge, both sampled at high-enough frequency (1 Hz to allow the study of relations between background noise on the seismometers and ocean waves and currents. The proximity of several land-based broadband seismic stations of the Berkeley Digital Seismic Network allows insightful comparisons of land/ocean background seismic noise at periods relevant to regional and teleseismic studies. The station is currently autonomous. Recording and battery packages are exchanged every 3 months during scheduled one day dives. Ultimately, this station will be linked to shore using continuous telemetry (cable and/or buoy and will contribute to the earthquake notification system in Northern California. We present examples of earthquake and noise data recorded during the first 6 months of operation of MOBB. Lessons learned from these and continued recordings will help understand the nature and character of background noise in regional off-shore environments and provide a reference for the installation of future off-shore temporary and permanent broadband seismic stations.

  11. 46 CFR 7.20 - Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and...

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block Island Sound and easterly entrance to Long Island Sound, NY. 7.20 Section 7.20... Atlantic Coast § 7.20 Nantucket Sound, Vineyard Sound, Buzzards Bay, Narragansett Bay, MA, Block...

  12. 33 CFR 334.762 - Naval Support Activity Panama City; North Bay and West Bay; restricted areas.

    Science.gov (United States)

    2010-07-01

    ... City; North Bay and West Bay; restricted areas. 334.762 Section 334.762 Navigation and Navigable Waters... REGULATIONS § 334.762 Naval Support Activity Panama City; North Bay and West Bay; restricted areas. (a) The... occurring within the active military security zone/s and offering navigational advice to ensure the...

  13. Historical contamination of PAHs, PCBs, DDTs, and heavy metals in Mississippi River Delta, Galveston Bay and Tampa Bay sediment cores.

    Science.gov (United States)

    Santschi, P H; Presley, B J; Wade, T L; Garcia-Romero, B; Baskaran, M

    2001-07-01

    Profiles of trace contaminant concentrations in sediment columns can be a natural archive from which pollutant inputs into coastal areas can be reconstructed. Reconstruction of historical inputs of anthropogenic chemicals is important for improving management strategies and evaluating the success of recent pollution controls measures. Here we report a reconstruction of historical contamination into three coastal sites along the US Gulf Coast: Mississippi River Delta, Galveston Bay and Tampa Bay. Within the watersheds of these areas are extensive agricultural lands as well as more than 50% of the chemical and refinery capacity of the USA. Despite this pollution potential, relatively low concentrations of trace metals and trace organic contaminants were found in one core from each of the three sites. Concentrations and fluxes of most trace metals found in surface sediments at these three sites, when normalized to Al, are typical for uncontaminated Gulf Coast sediments. Hydrophobic trace organic contaminants that are anthropogenic (polycyclic aromatic hydrocarbons, DDTs, and polychlorinated biphenyls) are found in sediments from all locations. The presence in surface sediments from the Mississippi River Delta of low level trace contaminants such as DDTs, which were banned in the early 1970's, indicate that they are still washed out from cultivated soils. It appears that the DDTs profile in that sediment core was produced by a combination of erosion processes of riverine and other sedimentary deposits during floods. Most of the pollutant profiles indicate that present-day conditions have improved from the more contaminated conditions in the 1950-1970's, before the advent of the Clean Water Act. PMID:11488356

  14. Persistent whole-bay red tide of Noctiluca scintillans in Manila Bay, Philippines

    OpenAIRE

    Furuya, Ken; Saito, Haruna; Rujinard, Sriwoon; Anil K. Vijayan; Omura, Takuo; Elsa E. Furio; Valeriano M. Borja; Sopana, Boonyapiwat; Thaithaworn, Lirdwitayaprasit

    2006-01-01

    Noctiluca scintillans, which contains a photosynthetic endosymbiont, Pedinomonas noctilucae, formed perennial red tides in Manila Bay, Philippines, occasionally covering almost whole area since 2001. A whole-bay scale red tide of the green Noctiluca in Manila Bay is described as the first step to elucidate the formation mechanism of the large scale blooming of the organism. A field survey was conducted in March 2004, when greenish discoloration due to N. scintillans was observed in the whole ...

  15. Holy grail at Baglan Bay

    Energy Technology Data Exchange (ETDEWEB)

    Watson, Jim

    1999-09-01

    The UK government's consent for the construction of a gas-fired power plant at Baglan Bay in South Wales is reported, and the growing popularity of economic combined-cycle gas turbine (CCGT) power plants and the resulting environmental improvements are noted . The combining of gas and steam turbines, design developments, and the UK moratorium on planning consents for gas fired power plants are discussed. General Electric's H System technology which will lower the amount of energy lost in the conversion of natural gas to electricity is described, and details of the ten most problematic CCGTs in the UK are given. The domination of the CCGT global market by four manufacturers, and the pressure on manufacturers to develop their designs are considered. (UK)

  16. Bayes linear covariance matrix adjustment

    CERN Document Server

    Wilkinson, Darren J

    1995-01-01

    In this thesis, a Bayes linear methodology for the adjustment of covariance matrices is presented and discussed. A geometric framework for quantifying uncertainties about covariance matrices is set up, and an inner-product for spaces of random matrices is motivated and constructed. The inner-product on this space captures aspects of our beliefs about the relationship between covariance matrices of interest to us, providing a structure rich enough for us to adjust beliefs about unknown matrices in the light of data such as sample covariance matrices, exploiting second-order exchangeability and related specifications to obtain representations allowing analysis. Adjustment is associated with orthogonal projection, and illustrated with examples of adjustments for some common problems. The problem of adjusting the covariance matrices underlying exchangeable random vectors is tackled and discussed. Learning about the covariance matrices associated with multivariate time series dynamic linear models is shown to be a...

  17. Holy grail at Baglan Bay

    International Nuclear Information System (INIS)

    The UK government's consent for the construction of a gas-fired power plant at Baglan Bay in South Wales is reported, and the growing popularity of economic combined-cycle gas turbine (CCGT) power plants and the resulting environmental improvements are noted . The combining of gas and steam turbines, design developments, and the UK moratorium on planning consents for gas fired power plants are discussed. General Electric's H System technology which will lower the amount of energy lost in the conversion of natural gas to electricity is described, and details of the ten most problematic CCGTs in the UK are given. The domination of the CCGT global market by four manufacturers, and the pressure on manufacturers to develop their designs are considered. (UK)

  18. Fecal indicator bacteria and Salmonella in ponds managed as bird habitat, San Francisco Bay, California, USA

    Science.gov (United States)

    Shellenbarger, G.G.; Athearn, N.D.; Takekawa, J.Y.; Boehm, A.B.

    2008-01-01

    Throughout the world, coastal resource managers are encouraging the restoration of previously modified coastal habitats back into wetlands and managed ponds for their ecosystem value. Because many coastal wetlands are adjacent to urban centers and waters used for human recreation, it is important to understand how wildlife can affect water quality. We measured fecal indicator bacteria (FIB) concentrations, presence/absence of Salmonella, bird abundance, and physico-chemical parameters in two coastal, managed ponds and adjacent sloughs for 4 weeks during the summer and winter in 2006. We characterized the microbial water quality in these waters relative to state water-quality standards and examined the relationship between FIB, bird abundance, and physico-chemical parameters. A box model approach was utilized to determine the net source or sink of FIB in the ponds during the study periods. FIB concentrations often exceeded state standards, particularly in the summer, and microbial water quality in the sloughs was generally lower than in ponds during both seasons. Specifically, the inflow of water from the sloughs to the ponds during the summer, more so than waterfowl use, appeared to increase the FIB concentrations in the ponds. The box model results suggested that the ponds served as net wetland sources and sinks for FIB, and high bird abundances in the winter likely contributed to net winter source terms for two of the three FIB in both ponds. Eight serovars of the human pathogen Salmonella were isolated from slough and pond waters, although the source of the pathogen to these wetlands was not identified. Thus, it appeared that factors other than bird abundance were most important in modulating FIB concentrations in these ponds.

  19. Food habits and organochlorine contaminants in the diet of black skimmers, Galveston Bay, Texas, USA

    Science.gov (United States)

    King, K.A.

    1989-01-01

    More than 500 food items of nestling Black Skimmers were identified representing 18 species of fish and 2 invertebrates. DDE and poly-chlorinated biphenyls (PCBs) were the only contaminants consistently detected in the black skimmer diet, carcass, and egg samples. Eggs contained 14 times the level of PCBs detected in the fish diet.

  20. Surface Elevation Change And Vertical Accretion In Created Mangroves In Tampa Bay, Florida, Usa

    Science.gov (United States)

    Mangroves protect coastlines, provide faunal habitat, and store large quantities of carbon (C). In South Florida and other parts of the Gulf of Mexico, large wetland areas, including mangrove forests, have been removed, degraded, or damaged. Wetland creation efforts have been use...

  1. Environmental PCBs in Guánica Bay, Puerto Rico: implications for community health.

    Science.gov (United States)

    Kumar, Naresh; Ramirez-Ortiz, Daisy; Solo-Gabriele, Helena M; Treaster, Joseph B; Carrasquillo, Olveen; Toborek, Michal; Deo, Sapna; Klaus, Jim; Bachas, Leonidas G; Whitall, David; Daunert, Sylvia; Szapocznik, Jose

    2016-02-01

    Guánica Bay, located in southwestern Puerto Rico, has suffered oil spills and other pollution discharges since the 1960s. Previous research showed elevated concentrations of polychlorinated biphenyls (PCBs) in coral reef and sediment. This research examined PCB concentrations in sediment and fish. Sediment and fish sampling in the bay was facilitated by community members. This study identified the second highest reported PCB level (129,300 ng/g) in sediment in the USA. Fish samples also showed elevated concentrations (1623 to 3768 ng/g), which were higher than the thresholds of safe levels of PCBs in fish for human consumption. The alarmingly high concentration of PCBs calls for proactive community engagement to bring awareness about contamination of the bay and more extensive sampling to test for the concentration of PCBs in seafood and the people of Guánica. This study also underscores the value of the involvement of local communities during sampling design aimed at identifying hot spots of contaminants. PMID:26122576

  2. A cold phase of the East Pacific triggers new phytoplankton blooms in San Francisco Bay

    Science.gov (United States)

    Cloern, J.E.; Jassby, A.D.; Thompson, J.K.; Hieb, K.A.

    2007-01-01

    Ecological observations sustained over decades often reveal abrupt changes in biological communities that signal altered ecosystem states. We report a large shift in the biological communities of San Francisco Bay, first detected as increasing phytoplankton biomass and occurrences of new seasonal blooms that began in 1999. This phytoplankton increase is paradoxical because it occurred in an era of decreasing wastewater nutrient inputs and reduced nitrogen and phosphorus concentrations, contrary to the guiding paradigm that algal biomass in estuaries increases in proportion to nutrient inputs from their watersheds. Coincidental changes included sharp declines in the abundance of bivalve mollusks, the key phytoplankton consumers in this estuary, and record high abundances of several bivalve predators: Bay shrimp, English sole, and Dungeness crab. The phytoplankton increase is consistent with a trophic cascade resulting from heightened predation on bivalves and suppression of their filtration control on phytoplankton growth. These community changes in San Francisco Bay across three trophic levels followed a state change in the California Current System characterized by increased upwelling intensity, amplified primary production, and strengthened southerly flows. These diagnostic features of the East Pacific "cold phase" lead to strong recruitment and immigration of juvenile flatfish and crustaceans into estuaries where they feed and develop. This study, built from three decades of observation, reveals a previously unrecognized mechanism of ocean-estuary connectivity. Interdecadal oceanic regime changes can propagate into estuaries, altering their community structure and efficiency of transforming land-derived nutrients into algal biomass. ?? 2007 by The National Academy of Sciences of the USA.

  3. Pb distribution and translocation in Jiaozhou Bay

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The trends of distribution, translocation and seasonal change of heavy metal Pb were studied based on the surface and bottom water sampling in Jiaozhou Bay in 1979, and compared with those in 1990's. The results showed that the source of Pb in the bay was from wastewater and sewage in the east of Jiaozhou Bay from ocean vessels. Pb concentration was higher in spring and lower in summer and autumn, and remained stable through sedimentation in the bottom layer. The overall water quality was good in 1970's. Compared with the environmental monitoring data of 1995-1999, Pb pollution had become serious. Therefore, more efforts should be made to protect the bay from Pb pollution.

  4. Corpus ChristiEast Matagorda Bay 1986

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Patterns of habitat utilization were compared among transplanted and natural Spartina alterniflora marshes in the Halls Lake area of Chocolate Bay in the Galveston...

  5. Bathymetry--Offshore Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the bathymetry and shaded-relief maps of the Offshore Half Moon Bay, California (raster data file is included in...

  6. San Antonio Bay 1986-1989

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The effect of salinity on utilization of shallow-water nursery habitats by aquatic fauna was assessed in San Antonio Bay, Texas. Overall, 272 samples were collected...

  7. Mercury distribution in the Jiaozhou Bay

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Jiaozhou Bay is a semi-enclosed bay, Qingdao, China. More than 10 rivers enter the bay, of which most take wastes from industrial and household discharges. According to historical seasonal investigations in May, August, November 1979, the content,distribution, and development of heavy metal mercury are analyzed as a historical reference. Water samples were taken from the surface and bottom. The results revealed clear seasonal and regional changes in both horizontal and vertical directions, and close relation with major discharging rivers and plankton production. The seawater was polluted more seriously in spring than in any other seasons.However, it was the cleanest in winter during which least waste was input with low plankton production. According to historical data,the state of mercury pollution in seawater was worsening in the period, and has been improving in recent years. Terrestrial contamination was the main reason for mercury pollution in the bay.

  8. Biscayne Bay Florida Bottlenose Dolphin Studies

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets include a compilation of small vessel based studies of bottlenose dolphins that reside within Biscayne Bay, Florida, adjacent estuaries and...

  9. Historical methyl mercury in San Francisco Bay

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — San Francisco Bay, California is considered a mercury-impaired watershed. Elevated concentrations of mercury are found in water and sediment as well as fish and...

  10. FL BAY SPECTROUT-POPULATION STATUS

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Juvenile spotted seatrout and other sportfish are being monitored annually over a 6-mo period in Florida Bay to assess their abundance over time relative to...

  11. South Bay Salt Ponds : Initial stewardship plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The California Department of Fish and Game and the U.S. Fish and Wildlife Service will operate and maintain the South Bay Salt Ponds under this Initial Stewardship...

  12. Underwater Video Sites in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of Jobos Bay, Puerto Rico were mapped and characterized using visual interpretation...

  13. Underwater Video Transects in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of Jobos Bay, Puerto Rico were mapped and characterized using visual interpretation...

  14. Willapa Bay, Washington Benthic Habitats 1995 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  15. Willapa Bay, Washington Benthic Habitats 1995 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  16. Willapa Bay, Washington Benthic Habitats 1995 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  17. Willapa Bay, Washington Benthic Habitats 1995 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In June 1995, the Columbia River Estuary Study Taskforce (CREST) acquired 295 true color aerial photographs (1:12,000) of Willapa Bay, Washington, from the State of...

  18. 2004 Saginaw Bay, Lake Huron, Michigan Lidar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This metadata document describes the collection and processing of Light Detection and Ranging (LIDAR) data over an area along the coast of Saginaw Bay, Lake Huron,...

  19. BENTHIC MACROFAUNAL ALIENS IN WILLAPA BAY

    Science.gov (United States)

    Benthic macrofaunal samples were collected at random stations in Willapa Bay, WA, in four habitats [eelgrass (Zostera marina), Atlantic cordgrass (Spartina alterniflora), mud shrimp (Upogebia pugettensis), ghost shrimp (Neotrypaea californiensis)] in 1996 and in seven habitats (Z...

  20. Bay Scallop Spawning, Survival, Growth Records

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bay Scallops are selected and cultured according to criteria of growth and survival. Morphological attributes have also been selected to assess heretibility....