Comparison of fishes in nearshore areas of the St. Lawrence River, New York over 35 years

Science.gov (United States)

Carlson, Douglas M.; McKenna, James E.

2014-01-01

Fishes of the nearshore waters of the St. Lawrence River provide forage for valuable sport fisheries and are important biological indicators of condition and change. This fish community differs slightly among various reaches of the St. Lawrence River from New York to Quebec (Carlson et al. 2006, Eckert and Hanlon 1977, Kapuscinski 2011, LaViolette et al. 2003, Mandrak et al. 2006, McKenna et al. 2005). Nearshore habitat has been described by McKenna et al. (2012), and others have suggested that there were changes over the last few decades (Clapsadl 1993, Kapuscinski and Farrell 2013). More definitive work needs to be completed on submerged aquatic vegetation habitats. In this paper, changes in the nearshore fish species composition for the New York reach from Cape Vincent to Moses-Saunders Dam are examined through comparison of results from 2009-2010 (McKenna et al. 2012) and 1976 surveys (Eckert and Hanlon 1977).

Nearshore Water Quality Estimation Using Atmospherically Corrected AVIRIS Data

Directory of Open Access Journals (Sweden)

Sima Bagheri

2011-02-01

Full Text Available The objective of the research is to characterize the surface spectral reflectance of the nearshore waters using atmospheric correction code—Tafkaa for retrieval of the marine water constituent concentrations from hyperspectral data. The study area is the nearshore waters of New York/New Jersey considered as a valued ecological, economic and recreational resource within the New York metropolitan area. Comparison of the Airborne Visible Infrared Imaging Spectrometer (AVIRIS measured radiance and in situ reflectance measurement shows the effect of the solar source and atmosphere in the total upwelling spectral radiance measured by AVIRIS. Radiative transfer code, Tafkaa was applied to remove the effects of the atmosphere and to generate accurate reflectance (R(0 from the AVIRIS radiance for retrieving water quality parameters (i.e., total chlorophyll. Chlorophyll estimation as index of phytoplankton abundance was optimized using AVIRIS band ratio at 675 nm and 702 nm resulting in a coefficient of determination of R2 = 0.98. Use of the radiative transfer code in conjunction with bio optical model is the main tool for using ocean color remote sensing as an operational tool for monitoring of the key nearshore ecological communities of phytoplankton important in global change studies.

Preferences for Management of Near-Shore Marine Ecosystems: A Choice Experiment in New Zealand

Directory of Open Access Journals (Sweden)

Sophal Chhun

2013-09-01

Full Text Available There is considerable interest in New Zealand in establishing “Customary Management Areas” (taiāpure and mātaitai and Marine Reserves to support Māori cultural practices and restore declining biodiversity and fish stocks. Allocation of near-shore marine areas for these management systems potentially benefits the larger public, but it has often been vigorously opposed by recreational and commercial fishers. This paper reports estimates of the relative values held by the public toward four potentially conflicting uses of near-shore marine areas. These estimates come from a web-based choice survey completed by 1055 respondents recruited from throughout New Zealand. The response rate was especially high at 60%. We present results weighted to the characteristics of the population and test the results against a variety of well-known sources of survey bias. Scenario development suggests that some reallocation of near-shore marine areas to any of the management systems under discussion alternative to the status quo is likely to yield a welfare gain. A combination of marine reserves and taiāpure is most preferred. The exercise supports the use of discrete choice experiments to provide crucial information about difficult-to-quantify public values for aspects of management of near-shore marine areas, such as proposed taiāpure, mātaitai, or marine reserves.

A Nested Nearshore Nutrient Model (N&Sup3;M) for ...

Science.gov (United States)

Nearshore conditions drive phenomena like harmful algal blooms (HABs), and the nearshore and coastal margin are the parts of the Great Lakes most used by humans. To assess conditions, optimize monitoring, and evaluate management options, a model of nearshore nutrient transport and algal dynamics is being developed. The model targets a “regional” spatial scale, similar to the Great Lakes Aquatic Habitat Framework's sub-basins, which divide the nearshore into 30 regions. Model runs are 365 days, a whole season temporal scale, reporting at 3 hour intervals. N³M uses output from existing hydrodynamic models and simple transport kinetics. The nutrient transport component of this model is largely complete, and is being tested with various hydrodynamic data sets. The first test case covers a 200 km² area between two major tributaries to Lake Michigan, the Grand and Muskegon. N³M currently simulates phosphorous and chloride, selected for their distinct in-lake transport dynamics; nitrogen will be added. Initial results for 2003, 2010, and 2015 show encouraging correlations with field measurements. Initially implemented in MatLab, the model is currently implemented in Python and leverages multi-processor computation. The 4D in-browser visualizer Cesium is used to view model output, time varying satellite imagery, and field observations. not applicable

Winds and the distribution of nearshore phytoplankton in a stratified lake.

Science.gov (United States)

Cyr, Hélène

2017-10-01

The distribution of phytoplankton in lakes is notoriously patchy and dynamic, but wind-driven currents and algal buoyancy/motility are thought to determine where algae accumulate. In this study, nearshore phytoplankton were sampled from different parts of a lake basin twice a day for 4-5 consecutive days, in the spring and in late summer, to test whether short-term changes in phytoplankton biomass and community composition can be predicted from wind-driven currents. On windy days, phytoplankton biomass was higher at downwind than at upwind nearshore sites, and the magnitude of this difference increased linearly with increasing wind speed. However, contrary to the generally assumed downwind phytoplankton aggregations, these differences were mostly due to upwelling activity and the dilution of phytoplankton at upwind nearshore sites. The distribution of individual taxa was also related to wind speed, but only during late stratification (except for cryptophytes), and these relationships were consistent with the buoyancy and motility of each group. On windy days, large diatoms and cyanobacteria concentrated upwind, neutrally buoyant taxa (green algae, small diatoms) were homogeneously distributed, and motile taxa (cryptophytes, chrysophytes, dinoflagellates) concentrated downwind. Predictable differences in the biomass and composition of phytoplankton communities could affect the efficiency of trophic transfers in nearshore areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

Predictive Modelling to Identify Near-Shore, Fine-Scale Seabird Distributions during the Breeding Season.

Science.gov (United States)

Warwick-Evans, Victoria C; Atkinson, Philip W; Robinson, Leonie A; Green, Jonathan A

2016-01-01

During the breeding season seabirds are constrained to coastal areas and are restricted in their movements, spending much of their time in near-shore waters either loafing or foraging. However, in using these areas they may be threatened by anthropogenic activities such as fishing, watersports and coastal developments including marine renewable energy installations. Although many studies describe large scale interactions between seabirds and the environment, the drivers behind near-shore, fine-scale distributions are not well understood. For example, Alderney is an important breeding ground for many species of seabird and has a diversity of human uses of the marine environment, thus providing an ideal location to investigate the near-shore fine-scale interactions between seabirds and the environment. We used vantage point observations of seabird distribution, collected during the 2013 breeding season in order to identify and quantify some of the environmental variables affecting the near-shore, fine-scale distribution of seabirds in Alderney's coastal waters. We validate the models with observation data collected in 2014 and show that water depth, distance to the intertidal zone, and distance to the nearest seabird nest are key predictors in the distribution of Alderney's seabirds. AUC values for each species suggest that these models perform well, although the model for shags performed better than those for auks and gulls. While further unexplained underlying localised variation in the environmental conditions will undoubtedly effect the fine-scale distribution of seabirds in near-shore waters we demonstrate the potential of this approach in marine planning and decision making.

Predictive Modelling to Identify Near-Shore, Fine-Scale Seabird Distributions during the Breeding Season.

Directory of Open Access Journals (Sweden)

Victoria C Warwick-Evans

Full Text Available During the breeding season seabirds are constrained to coastal areas and are restricted in their movements, spending much of their time in near-shore waters either loafing or foraging. However, in using these areas they may be threatened by anthropogenic activities such as fishing, watersports and coastal developments including marine renewable energy installations. Although many studies describe large scale interactions between seabirds and the environment, the drivers behind near-shore, fine-scale distributions are not well understood. For example, Alderney is an important breeding ground for many species of seabird and has a diversity of human uses of the marine environment, thus providing an ideal location to investigate the near-shore fine-scale interactions between seabirds and the environment. We used vantage point observations of seabird distribution, collected during the 2013 breeding season in order to identify and quantify some of the environmental variables affecting the near-shore, fine-scale distribution of seabirds in Alderney's coastal waters. We validate the models with observation data collected in 2014 and show that water depth, distance to the intertidal zone, and distance to the nearest seabird nest are key predictors in the distribution of Alderney's seabirds. AUC values for each species suggest that these models perform well, although the model for shags performed better than those for auks and gulls. While further unexplained underlying localised variation in the environmental conditions will undoubtedly effect the fine-scale distribution of seabirds in near-shore waters we demonstrate the potential of this approach in marine planning and decision making.

The Future of Nearshore Processes Research

Science.gov (United States)

Elko, N.; Feddersen, F.; Foster, D. L.; Holman, R. A.; McNinch, J.; Ozkan-Haller, H. T.; Plant, N. G.; Raubenheimer, B.; Elgar, S.; Hay, A. E.; Holland, K. T.; Kirby, J. T., Jr.; Lippmann, T. C.; Miller, J. K.; Stockdon, H. F.; Ashton, A. D.; Boehm, A. B.; Clark, D.; Cowen, E.; Dalyander, S.; Gelfenbaum, G. R.; Hapke, C. J.; MacMahan, J.; McNamara, D.; Mulligan, R. P.; Palmsten, M. L.; Ruggiero, P.; Sherwood, C. R.; Hsu, T. J.

2014-12-01

Over 70 members of the nearshore coastal processes research community convened in April 2014 to discuss a vision for the future of nearshore science while celebrating the memories and contributions of our recently departed colleague, Abby Sallenger. The participants reviewed community accomplishments over the past four decades. Federal agencies, including FEMA, NOAA, NPS, USGS, USACE, and NRL discussed the most pressing societal needs within the coastal zone. The group engaged in a retrospective of the last four decades of progress, assessed the current status and limitations of nearshore processes research, and developed a vision for the future that focuses on societally relevant problems. The top research topics identified included: Long-term Coastal Impacts: Meaningfully improve our understanding and prediction of the long-term coastal effects of sea level rise and changes in storminess patterns and associated efforts to protect coastal infrastructure. Extreme Events: Coastal flooding, overland flow, and concurrent morphological evolution during extreme events including the subsequent process of coastal recovery. Human and Ecosystem Health: Linkages between physical coastal processes (transport and mixing) and land-based pollution (pathogens, nutrients, toxic contaminants). Critical for addressing these research questions is enabling infrastructure, such as new observational tools and data sets, models, and nearshore-community communication and collaboration. Idea and concepts developed during the meeting (to be published in Shore and Beach) will be presented to foster collaboration and advocacy amongst the wider nearshore community. Meeting materials are available at: https://scripps.ucsd.edu/centers/nearshorefuture/.

Physical, chemical, and biological data collected in the Beaufort Sea as part of the Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA) from 1999 to 2007 (NODC Accession 0001921)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data contains information specifically for the Arctic Nearshore Impact Monitoring in the Development Area (ANIMIDA 1999 - 2002) and continuation of Arctic...

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

Science.gov (United States)

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

2006-01-01

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

Influence of Cladophora-Quagga Mussel Assemblages on Nearshore Methylmercury Production in Lake Michigan.

Science.gov (United States)

Lepak, Ryan F; Krabbenhoft, David P; Ogorek, Jacob M; Tate, Michael T; Bootsma, Harvey A; Hurley, James P

2015-07-07

Recent spread of invasive mussels in Lake Michigan has altered primary productivity in the nearshore zone, resulting in proliferation of filamentous benthic green algae (Cladophora glomerata). In areas of dense Cladophora and quagga mussel (Dreissena bugensis) assemblages, as well as in regions where sloughed Cladophora accumulates, methylmercury (MeHg) production is enhanced. A shoreline transect from a river mouth through waters overlying Cladophora/quagga-rich zones showed that aqueous MeHg concentrations increased, despite river dilution. Cladophora, as primary producers, ranged from 0.6 to 7.5 ng g(-1) MeHg [4-47% of total mercury (Hg) as MeHg], and were higher than MeHg concentrations in offshore-collected seston. Concentrations of MeHg in decaying Cladophora accumulated onshore ranged from 2.6 to 18.0 ng g(-1) MeHg (18-41% as MeHg) and from 0.1 to 3.0 ng g(-1) MeHg (2-21% as MeHg) in deposits of recently sloughed and accumulated Cladophora in a nearshore topographical depression. Relative to offshore open waters, interstitial waters within decaying Cladophora from onshore and nearshore deposits were elevated in MeHg concentration, 1000- and 10-fold, respectively. Percent Hg as MeHg was also elevated (65-75% and 9-19%, respectively for onshore interstitial water and nearshore interstitial water, compared to 0.2-3.3% as MeHg for open water). Quagga mussels collected within growing Cladophora beds in the nearshore zone were significantly higher in MeHg than offshore counterparts. Our combined results suggest that recent changes in nearshore primary production contributes to MeHg production and bioaccumulation in Lake Michigan.

Approach to downstream planning for nearshore response and sensitive areas protection outside Prince William Sound, Alaska

International Nuclear Information System (INIS)

DeCola, E.G.; Robertson, T.L.; Robertson, R.; Banta, J.

2004-01-01

This study assessed the need for an oil spill response plan for downstream coastal communities that could be affected by oil spilled from tankers travelling in Prince William Sound, Alaska. For the purpose of oil spill contingency planning, the State of Alaska has been divided into the Kodiak and Cook Inlet sub-areas that are at risk for downstream impacts from a Prince William Sound oil spill. The 1989 Exxon Valdez oil spill provided an example of a worst-case scenario oil spill from a tanker in Prince William Sound, but the oil spill planning system that has evolved in Alaska does not adequately plan for on oil spill that originates in one sub-area of the state, but impacts other sub-areas in the downstream spill path. This study analyzed the gaps that exist in the current response planning system in the Prince William Sound, Cook Inlet and Kodiak sub-areas. A method was proposed to improve the existing response plans so that emergency response teams are better prepared to manage cross-boundary oil spills originating in Prince William Sound. The proposed method focuses on nearshore response and sensitive areas protection for coastlines and communities that are at risk for oil spills from a tanker travelling the Trans-Alaska Pipeline System (TAPS). 11 refs., 3 figs

California coast nearshore processes study. [nearshore currents, sediment transport, estuaries, and river discharge

Science.gov (United States)

Pirie, D. M.; Steller, D. D. (Principal Investigator)

1973-01-01

The author has identified the following significant results. Large scale sediment plumes from intermittent streams and rivers form detectable seasonal patterns on ERTS-1 imagery. The ocean current systems, as plotted from three California coast ERTS mosaics, were identified. Offshore patterns of sediment in areas such as the Santa Barbara Channel are traceable. These patterns extend offshore to heretofore unanticipated ranges as shown on the ERTS-1 imagery. Flying spot scanner enhancements of NASA tapes resulted in details of subtle and often invisible (to the eye) nearshore features. The suspended sediments off San Francisco and in Monterey Bay are emphasized in detail. These are areas of extremely changeable offshore sediment transport patterns. Computer generated contouring of radiance levels resulted in maps that can be used in determining surface and nearsurface suspended sediment distribution. Tentative calibrations of ERTS-1 spectral brightness against sediment load have been made using shipboard measurements. Information from the combined enhancement and interpretation techniques is applicable to operational coastal engineering programs.

Land-use planning for nearshore ecosystem services—the Puget Sound Ecosystem Portfolio Model

Science.gov (United States)

Byrd, Kristin

2011-01-01

The 2,500 miles of shoreline and nearshore areas of Puget Sound, Washington, provide multiple benefits to people—"ecosystem services"—including important fishing, shellfishing, and recreation industries. To help resource managers plan for expected growth in coming decades, the U.S. Geological Survey Western Geographic Science Center has developed the Puget Sound Ecosystem Portfolio Model (PSEPM). Scenarios of urban growth and shoreline modifications serve as model inputs to develop alternative futures of important nearshore features such as water quality and beach habitats. Model results will support regional long-term planning decisions for the Puget Sound region.

Mortality of Kalliapseudes schubartii in unvegetated soft bottoms of the estuarine region of the Lagoa dos Patos

Directory of Open Access Journals (Sweden)

Fonseca Duane Barros

2006-01-01

Full Text Available Studies were carried iut on seasonal mortality by taking samples of Kalliapseudes schubartii (Crustacea: Tanaidacea for a year in the estuarine region of the Lagoa dos Patos (southern Brazil. Results demonstrated no significant difference in seasonal mortality rates, which suggest that populations of K. schubartii was heavily preyed on year round and that an assumption of a significantly higher mortality in summer/autumn than in spring/winter might not be held in unvegetated soft bottoms of the estuarine regions of the Lagoa dos Patos.

Phosphorus mobilization by sulfide oxidation in carbonate sediments from seagrass and unvegetated sites in the US Virgin Islands

DEFF Research Database (Denmark)

Jensen, Henning; Pedersen, Ole; Koch, M. R.

PHOSPHORUS MOBILIZATION BY SULFIDE OXIDATION IN CARBONATE SEDIMENTS FROM SEAGRASS AND UNVEGETATED SITES IN THE US VIRGIN ISLANDS Sulfide produced by sulfate reduction (SR) can be oxidized by seagrass root O2 flux in shallow carbonate sediments low in Fe. The sulfuric acid produced from sulfide...... oxidation, as well as metabolic acids from aerobic respiration, has the potential to mobilize solid phase phosphorus (P) pools in support of seagrass nutrition. Fresh sediments from four US Virgin Islands sites were modestly acidified to near-neutral pH in slurries. Following sulfuric acid amendments...

Thirty Years of Nearshore Research

Science.gov (United States)

Stanton, T. P.

2006-12-01

An assessment of Ed Thornton's contributions to nearshore wave, current and morphology research on the eve of his retirement reveals his ability to identify important unresolved processes, and to participate in multidisciplinary research programs that address those issues. While doing this, he has consistently helped foster the new generations of field scientists both by supervising strong masters and PhD students from around the world, and through working with successful postdoctoral students, many of whom will present talks in this session. This presentation will summarize the major field programs that he has very actively participated in starting from my first field work with him as a colleague/helper in the NSTS Blacks Beach and Santa Barbara experiments. In reviewing these experiments it is interesting to see the evolution of our understanding of the surf zone from simplified 2D wave breaking processes to the 3D wave/current/sediment transport problems seen in morphologically controlled rip currents, both through our ability to measure these processes, but also in the sophistication of numerical models of the nearshore. This review also shows how the consistent and well directed basic research funding from the Coastal Geosciences program at ONR has greatly benefited the Navy and the community at large. I know the nearshore community looks forward to continued associations with him during his very active retirement.

Queen conch (Strombus gigas testis regresses during the reproductive season at nearshore sites in the Florida Keys.

Directory of Open Access Journals (Sweden)

Daniel J Spade

Full Text Available BACKGROUND: Queen conch (Strombus gigas reproduction is inhibited in nearshore areas of the Florida Keys, relative to the offshore environment where conchs reproduce successfully. Nearshore reproductive failure is possibly a result of exposure to environmental factors, including heavy metals, which are likely to accumulate close to shore. Metals such as Cu and Zn are detrimental to reproduction in many mollusks. METHODOLOGY/PRINCIPAL FINDINGS: Histology shows gonadal atrophy in nearshore conchs as compared to reproductively healthy offshore conchs. In order to determine molecular mechanisms leading to tissue changes and reproductive failure, a microarray was developed. A normalized cDNA library for queen conch was constructed and sequenced using the 454 Life Sciences GS-FLX pyrosequencer, producing 27,723 assembled contigs and 7,740 annotated transcript sequences. The resulting sequences were used to design the microarray. Microarray analysis of conch testis indicated differential regulation of 255 genes (p<0.01 in nearshore conch, relative to offshore. Changes in expression for three of four transcripts of interest were confirmed using real-time reverse transcription polymerase chain reaction. Gene Ontology enrichment analysis indicated changes in biological processes: respiratory chain (GO:0015992, spermatogenesis (GO:0007283, small GTPase-mediated signal transduction (GO:0007264, and others. Inductively coupled plasma-mass spectrometry analysis indicated that Zn and possibly Cu were elevated in some nearshore conch tissues. CONCLUSIONS/SIGNIFICANCE: Congruence between testis histology and microarray data suggests that nearshore conch testes regress during the reproductive season, while offshore conch testes develop normally. Possible mechanisms underlying the testis regression observed in queen conch in the nearshore Florida Keys include a disruption of small GTPase (Ras-mediated signaling in testis development. Additionally, elevated tissue

Use of a Land-Based, Dual-Parameter Analyzer for Tracking Ocean Acidification in Nearshore Coastal Habitats

Science.gov (United States)

Shea, M.; Alin, S. R.; Evans, W.; Sutton, A.; Hales, B. R.; Newton, J.; Feely, R. A.

2016-12-01

In 2007 to 2008, U.S. Pacific Northwest shellfish hatcheries experienced unprecedented larval mortality, attributed to upwelling along the Washington-Oregon coast that brought seawater enriched in anthropogenic CO2 and undersaturated with respect to aragonite to the surface. In response, several hatcheries have been outfitted with land-based analyzers to measure CO2 partial pressure (pCO2) and total dissolved CO2 (TCO2) through U.S. IOOS and NOAA OAP funding. This analyzer, developed at Oregon State University and known as the `Burke-O-Lator,' allows users to track CO2 system parameters in real-time. The data are available in near real-time on the IOOS Pacific Region Ocean Acidification (IPACOA) data portal, which feeds to the Global Ocean Acidification Observing Network (GOA-ON). Here, we explore the broader use of this system as an environmental monitoring tool. Most of the high-quality OA time-series locations in GOA-ON are in the open and coastal ocean, yet many areas of biological interest—such as shellfish hatcheries, shellfish farms, and coastal laboratories—are in the nearshore area of the coastal zone. A truly globally integrated assessment of OA must include nearshore conditions, which have been shown to be quite different in terms of variability, drivers, and range. We evaluated two pCO2 time-series from the coastal nearshore: the Taylor Shellfish Hatchery Burke-O-Lator system on the shore of Dabob Bay in Puget Sound, WA, and the nearby but offshore Dabob ORCA buoy MAPCO2 system within the bay. Preliminary comparison of three years of data reveals similar patterns despite differences in location and seawater intake depth, highlighting the opportunity for the addition of coupled nearshore biology and biogeochemistry measurements in GOA-ON. In addition, the well-calibrated, dual-parameter nature of the system is important for constraining nearshore chemistry, as biology, groundwater, and river inputs can lead to strong variability in carbonate

Nearshoring Practices

DEFF Research Database (Denmark)

Slepniov, Dmitrij; Brazinskas, Sigitas; Wæhrens, Brian Vejrum

2013-01-01

Purpose: The principal objective of this paper is to unravel and assess current nearshoring practices and their outlook in the Baltic region. Design/methodology/approach: We draw on the offshoring and outsourcing literature and use mixed methods of enquiry, including case studies, survey techniques...... and secondary statistical data. Part of the empirical base of the study is an examination of three Scandinavian firms that offshore their operations to vendors in the Baltics. To provide a more complete view of the practices and processes of offshoring in the region, we complement the case studies of Swedish...

Shallow-water, nearshore current dynamics in Algoa Bay, South ...

African Journals Online (AJOL)

Nearshore currents play a vital role in the transport of eggs and larval stages of fish. However, little is known about their complexity and the implications for dispersal of fish larvae. The study describes the complexity of the shallow nearshore environment in eastern Algoa Bay, on the south-east coast of South Africa, and its ...

Nearshore Versus Offshore: Comparative Cost and Competitive Advantages

DEFF Research Database (Denmark)

Klinge Jacobsen, Henrik; Hevia Koch, Pablo Alejandro; Wolter, Christoph

2016-01-01

Currently there exist high expectations for the development of wind energy, particularly in Europe, out of which offshore wind turbine developments will be central as tools to achieve current energy targets. The choice between nearshore and (far)-offshore is particularly relevant, both because of...... of increased public resistance due to visual disamenities produced by nearshore projects, and because of the potential cost reduction benefits attained by building wind farms closer to the shore....

Exxon Valdez Oil Spill Restoration Project final report: Monitoring for evaluation of recovery and restoration of injured nearshore resources

Science.gov (United States)

Ballachey, Brenda E.; Bodkin, James L.; Kloecker, Kim; Dean, Tom; Colettie, Heather A

2015-01-01

In 2012, we completed three consecutive years of full field sampling in WPWS for EVOS Restoration Project 10100750. Nearshore monitoring was conducted in collaboration with the NPS SWAN I&M program and, beginning in 2012, as part of the EVOSTC GWA program. Data collection was done in accordance with standard operating procedures set forth to monitor marine water chemistry and quality, marine intertidal invertebrates, kelps and seagrasses, marine birds, black oystercatchers, and sea otters. Summer sampling in 2012 represented the fourth year of sampling in WPWS (an initial year of sampling was done in WPWS in 2007; EVOS Restoration Project 070750). Based on our monitoring of nearshore species in WPWS, and comparisons of data from WPWS and other areas within the Gulf of Alaska, we have no evidence of continued injury to biological resources at the spatial scales we are monitoring. A key finding is that recovery of the sea otter population is no longer constrained by exposure to lingering oil; this is consistent with related EVOSTC studies on harlequin ducks (Restoration Project 12120114-Q). We anticipate continued annual nearshore monitoring in WPWS and at KATM and KEFJ under GWA, with data summaries and analyses including all three areas to provide a larger spatial and temporal context to the understanding of processes and patterns in nearshore ecosystems of the GOA which were impacted by the EVOS of 1989.

Nearshore Survey System Evaluation

Science.gov (United States)

2017-12-01

environmental challenges. ERDC develops innovative solutions in civil and military engineering , geospatial sciences, water resources, and environmental...CRAB: A Unique Nearshore Surveying Vehicle.” American Society of Civil Engineers , Journal of Surveying Engineering 110(1): 1–7. Clausner, J. E., W...unlimited. The U.S. Army Engineer Research and Development Center (ERDC) solves the nation’s toughest engineering and

Simulating Radionuclide Migrations of Low-level Wastes in Nearshore Environment

Science.gov (United States)

Lu, C. C.; Li, M. H.; Chen, J. S.; Yeh, G. T.

2016-12-01

Tunnel disposal into nearshore mountains was tentatively selected as one of final disposal sites for low-level wastes in Taiwan. Safety assessment on radionuclide migrations in far-filed may involve geosphere processes under coastal environments and into nearshore ocean. In this study the 3-D HYDROFEOCHE5.6 numerical model was used to perform simulations of groundwater flow and radionuclide transport with decay chains. Domain of interest on the surface includes nearby watersheds delineated by digital elevation models and nearshore seabed. As deep as 800 m below the surface and 400 m below sea bed were considered for simulations. The disposal site was located at 200m below the surface. Release rates of radionuclides from near-field was estimated by analytical solutions of radionuclide diffusion with decay out of engineered barriers. Far-field safety assessments were performed starting from the release of radionuclides out of engineered barriers to a time scale of 10,000 years. Sensitivity analyses of geosphere and transport parameters were performed to improve our understanding of safety on final disposal of low-level waste in nearshore environments.

Cooperative trap survey for nearshore groundfish

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This pilot study is designed to evaluate a fishery-independent, cooperative sampling methodology for nearshore groundfish species, with an emphasis on species in the...

Evaluation of Using Caged Clams to Monitor Contaminated Groundwater Exposure in the Near-Shore Environment of the Hanford Site 300 Area

Energy Technology Data Exchange (ETDEWEB)

Larson, Kyle B.; Poston, Ted M.; Tiller, Brett L.

2008-01-31

The Asiatic clam (Corbicula fluminea) has been identified as an indicator species for locating and monitoring contaminated groundwater in the Columbia River. Pacific Northwest National Laboratory conducted a field study to explore the use of caged Asiatic clams to monitor contaminated groundwater upwelling in the 300 Area near-shore environment and assess seasonal differences in uranium uptake in relation to seasonal flow regimes of the Columbia River. Additional objectives included examining the potential effects of uranium accumulation on growth, survival, and tissue condition of the clams. This report documents the field conditions and procedures, laboratory procedures, and statistical analyses used in collecting samples and processing the data. Detailed results are presented and illustrated, followed by a discussion comparing uranium concentrations in Asiatic clams collected at the 300 Area and describing the relationship between river discharge, groundwater indicators, and uranium in clams. Growth and survival, histology, and other sources of environmental variation also are discussed.

The Future of Nearshore Processes Research: U.S. Integrated Coastal Research Program

Science.gov (United States)

Elko, N.; Feddersen, F.; Foster, D. L.; Hapke, C. J.; Holman, R. A.; McNinch, J.; Mulligan, R. P.; Ozkan-Haller, H. T.; Plant, N. G.; Raubenheimer, B.

2016-02-01

The authors, representing the acting Nearshore Advisory Council, have developed an implementation plan for a U.S. Nearshore Research Program based on the 2015 Future of Nearshore Processes report that was authored by the nearshore community. The objectives of the plan are to link research programs across federal agencies, NGOs, industry, and academia into an integrated national program and to increase academic and NGO participation in federal agency nearshore processes research. A primary recommendation is interagency collaboration to build a research program that will coordinate and fund U.S. nearshore processes research across three broad research themes: 1) long-term coastal evolution due to natural and anthropogenic processes; 2) extreme events; and 3) physical, biological and chemical processes impacting human and ecosystem health. The plan calls for a new program to be developed by an executive committee of federal agency leaders, NGOs, and an academic representative, created similarly to the existing NOPP program. This leadership will be established prior to the 2016 Ocean Sciences meeting and will have agreed on responsibilities and a schedule for development of the research program. To begin to understand the scope of today's U.S. coastal research investment, a survey was distributed to ten federal agency R&D program heads. Six of the ten agencies indicated that they fund coastal research, with a combined annual coastal research budget of nearly 100 million (NSF has not responded). The priority of the three research themes were ranked nearly equally and potential research support ranged from 15-19 million for each theme, with approximately 12 million as direct contribution to academic research. Beyond addressing our fundamental science questions, it is critical that the nearshore community stay organized to represent academic interests on the new executive committee. The program goal is the integration of academic, NGO, and federal agencies.

Functional shifts in unvegetated, perhumid, recently-deglaciated soils do not correlate with shifts in soil bacterial community composition.

Science.gov (United States)

Sattin, Sarah R; Cleveland, Cory C; Hood, Eran; Reed, Sasha C; King, Andrew J; Schmidt, Steven K; Robeson, Michael S; Ascarrunz, Nataly; Nemergut, Diana R

2009-12-01

Past work in recently deglaciated soils demonstrates that microbial communities undergo shifts prior to plant colonization. To date, most studies have focused on relatively 'long' chronosequences with the ability to sample plant-free sites over at least 50 years of development. However, some recently deglaciated soils feature rapid plant colonization and questions remain about the relative rate of change in the microbial community in the unvegetated soils of these chronosequences. Thus, we investigated the forelands of the Mendenhall Glacier near Juneau, AK, USA, where plants rapidly establish. We collected unvegetated samples representing soils that had been ice-free for 0, 1, 4, and 8 years. Total nitrogen (N) ranged from 0.00 approximately 0.14 mg/g soil, soil organic carbon pools ranged from 0.6 approximately 2.3 mg/g soil, and both decreased in concentration between the 0 and 4 yr soils. Biologically available phosphorus (P) and pH underwent similar dynamics. However, both pH and available P increased in the 8 yr soils. Nitrogen fixation was nearly undetectable in the most recently exposed soils, and increased in the 8 yr soils to approximately 5 ng N fixed/cm(2)/h, a trend that was matched by the activity of the soil N-cycling enzymes urease and beta-l,4-N-acetyl-glucosa-minidase. 16S rRNA gene clone libraries revealed no significant differences between the 0 and 8 yr soils; however, 8 yr soils featured the presence of cyanobacteria, a division wholly absent from the 0 yr soils. Taken together, our results suggest that microbes are consuming allochtonous organic matter sources in the most recently exposed soils. Once this carbon source is depleted, a competitive advantage may be ceded to microbes not reliant on in situ nutrient sources.

Dynamics of Nearshore Sand Bars and Infra-gravity Waves: The Optimal Theory Point of View

Science.gov (United States)

Bouchette, F.; Mohammadi, B.

2016-12-01

It is well known that the dynamics of near-shore sand bars are partly controlled by the features (location of nodes, amplitude, length, period) of the so-called infra-gravity waves. Reciprocally, changes in the location, size and shape of near-shore sand bars can control wave/wave interactions which in their turn alter the infra-gravity content of the near-shore wave energy spectrum. The coupling infra-gravity / near-shore bar is thus definitely two ways. Regarding numerical modelling, several approaches have already been considered to analyze such coupled dynamics. Most of them are based on the following strategy: 1) define an energy spectrum including infra-gravity, 2) tentatively compute the radiation stresses driven by this energy spectrum, 3) compute sediment transport and changes in the seabottom elevation including sand bars, 4) loop on the computation of infra-gravity taking into account the morphological changes. In this work, we consider an alternative approach named Nearshore Optimal Theory, which is a kind of breakdown point of view for the modeling of near-shore hydro-morphodynamics and wave/ wave/ seabottom interactions. Optimal theory applied to near-shore hydro-morphodynamics arose with the design of solid coastal defense structures by shape optimization methods, and is being now extended in order to model dynamics of any near-shore system combining waves and sand. The basics are the following: the near-shore system state is through a functional J representative of the energy of the system in some way. This J is computed from a model embedding the physics to be studied only (here hydrodynamics forced by simple infra-gravity). Then the paradigm is to say that the system will evolve so that the energy J tends to minimize. No really matter the complexity of wave propagation nor wave/bottom interactions. As soon as J embeds the physics to be explored, the method does not require a comprehensive modeling. Near-shore Optimal Theory has already given

Nearshore circulation on a sea breeze dominated beach during intense wind events

Science.gov (United States)

Torres-Freyermuth, Alec; Puleo, Jack A.; DiCosmo, Nick; Allende-Arandía, Ma. Eugenia; Chardón-Maldonado, Patricia; López, José; Figueroa-Espinoza, Bernardo; de Alegria-Arzaburu, Amaia Ruiz; Figlus, Jens; Roberts Briggs, Tiffany M.; de la Roza, Jacobo; Candela, Julio

2017-12-01

A field experiment was conducted on the northern Yucatan coast from April 1 to April 12, 2014 to investigate the role of intense wind events on coastal circulation from the inner shelf to the swash zone. The study area is characterized by a micro-tidal environment, low-energy wave conditions, and a wide and shallow continental shelf. Furthermore, easterly trade winds, local breezes, and synoptic-scale events, associated with the passage of cold-fronts known as Nortes, are ubiquitous in this region. Currents were measured concurrently at different cross-shore locations during both local and synoptic-scale intense wind events to investigate the influence of different forcing mechanisms (i.e., large-scale currents, winds, tides, and waves) on the nearshore circulation. Field observations revealed that nearshore circulation across the shelf is predominantly alongshore-directed (westward) during intense winds. However, the mechanisms responsible for driving instantaneous spatial and temporal current variability depend on the weather conditions and the across-shelf location. During local strong sea breeze events (W > 10 m s-1 from the NE) occurring during spring tide, westward circulation is controlled by the tides, wind, and waves at the inner-shelf, shallow waters, and inside the surf/swash zone, respectively. The nearshore circulation is relaxed during intense land breeze events (W ≈ 9 m s-1 from the SE) associated with the low atmospheric pressure system that preceded a Norte event. During the Norte event (Wmax≈ 15 m s-1 from the NNW), westward circulation dominated outside the surf zone and was correlated to the Yucatan Current, whereas wave breaking forces eastward currents inside the surf/swash zone. The latter finding implies the existence of large alongshore velocity shear at the offshore edge of the surf zone during the Norte event, which enhances mixing between the surf zone and the inner shelf. These findings suggest that both sea breezes and Nortes play

Formation and evolution of nearshore sandbars

NARCIS (Netherlands)

Smit, M.W.J.

2010-01-01

The aim of this study is to understand whether hydrodynamic processes or geometrical characteristics play a dominant role in the response of the nearshore sandbar system to hydrodynamic conditions. To that end a depth-averaged (2DH) process-based model has been used to compute the morphological

Preliminary evaluation of the physical impacts of a nearshore sand extraction project

International Nuclear Information System (INIS)

Anctil, F.; Ouellet, Y.

1991-01-01

A review is presented of the potential physical impacts of a nearshore sand extraction project in the Gulf of St. Lawrence. In Canada, sand extraction is mainly limited to the Beaufort Sea area, where in 1982 alone 15 million tonnes of aggregate was dredged to satisfy the requirements of offshore petroleum exploration; but there is much experience in nearshore dredging in Europe. Criteria related to impacts, developed for conditions prevailing in the North Sea (England) and the Gulf of Gascogne (France) are adapted to meet the more moderate hydrodynamic impacts of an extraction project in the Gulf of St. Lawrence. Potential impacts of extraction projects include destruction of sand bars or dunes, direct erosion resulting from beach drawdown or sedimentation interference, and impacts on littoral drift due to modified wave refraction patterns. Three schemes for the sand extraction are considered, and from the results, a fourth scheme is elaborated in such a way as to limit the negative impacts to the minor category. 17 refs., 5 figs., 4 tabs

Monitoring in the nearshore: A process for making reasoned decisions

Science.gov (United States)

Bodkin, James L.; Dean, T.A.

2003-01-01

Over the past several years, a conceptual framework for the GEM nearshore monitoring program has been developed through a series of workshops. However, details of the proposed monitoring program, e.g. what to sample, where to sample, when to sample and at how many sites, have yet to be determined. In FY 03 we were funded under Project 03687 to outline a process whereby specific alternatives to monitoring are developed and presented to the EVOS Trustee Council for consideration. As part of this process, two key elements are required before reasoned decisions can be made. These are: 1) a comprehensive historical perspective of locations and types of past studies conducted in the nearshore marine communities within Gulf of Alaska, and 2) estimates of costs for each element of a proposed monitoring program. We have developed a GIS database that details available information from past studies of selected nearshore habitats and species in the Gulf of Alaska and provide a visual means of selecting sites based (in part) on the locations for which historical data of interest are available. We also provide cost estimates for specific monitoring plan alternatives and outline several alternative plans that can be accomplished within reasonable budgetary constraints. The products that we will provide are: 1) A GIS database and maps showing the location and types of information available from the nearshore in the Gulf of Alaska; 2) A list of several specific monitoring alternatives that can be conducted within reasonable budgetary constraints; and 3) Cost estimates for proposed tasks to be conducted as part of the nearshore program. Because data compilation and management will not be completed until late in FY03 we are requesting support for close-out of this project in FY 04.

Preliminary Nearshore Sedimentation Rate Analysis of the Tuungane Project Northern Mahale Conservation Area, Lake Tanganyika (Tanzania)

Science.gov (United States)

Smiley, R. A.; McGlue, M. M.; Yeager, K. M.; Soreghan, M. J.; Lucas, J.; Kimirei, I.; Mbonde, A.; Limbu, P.; Apse, C.

2017-12-01

The combined effects of climate change, overfishing, and sediment pollution are altering Lake Tanganyika's littoral fisheries in profoundly negative ways. One method for conserving critical fish resources and safeguarding biodiversity in Lake Tanganyika is by establishing small-scale nearshore protected zones, which can be administrated by lakeshore villagers organized into beach management units (BMUs). Each BMU endeavors to manage offshore "no-catch" protected zones, prohibit the use of illegal fishing gear, and promote sustainable agriculture that abates erosion in the lake watershed, in order to mitigate sediment pollution in the lake. We adopted a limnogeological approach to assist in characterizing the littoral zone associated with BMUs in the northern Mahale region of Lake Tanganyika (Tanzania), a critical conservation area for the Nature Conservancy's Tuungane Project (https://www.nature.org/ourinitiatives/regions/africa/wherewework/tuungane-project.xml). We hypothesized that BMUs with heavy onshore agricultural activity would experience relatively high offshore sedimentation rates, due to enhanced sediment-laden runoff in the wet season. Such changes are predicted to alter benthic substrates and degrade habitat available for fish spawning. We mapped bathymetry and sediment types along a 29 km2 area of the littoral zone using high-resolution geophysical tools, and assessed short-term sedimentation rates using sediment cores and radionuclide geochronology (210Pb). Initial results from 210Pb analyses show that sedimentation rates at the mud-line ( 85-100 m water depth) are relatively slow but spatially variable in the northern Mahale area. Offshore of the Kalilani village BMU, linear sedimentation rates are 0.50 mm/yr. By contrast, sedimentation rates offshore from the Igualula village BMU are 0.90-1.30 mm/yr. Higher sedimentation rates near Igualula are consistent with greater sediment inputs from the nearby Lagosa River and its watershed, which has been

Southwest Washington littoral drift restoration—Beach and nearshore morphological monitoring

Science.gov (United States)

Stevens, Andrew W.; Gelfenbaum, Guy; Ruggiero, Peter; Kaminsky, George M.

2012-01-01

A morphological monitoring program has documented the placement and initial dispersal of beach nourishment material (280,000 m3) placed between the Mouth of the Columbia River (MCR) North Jetty and North Head, at the southern end of the Long Beach Peninsula in southwestern Washington State. A total of 21 topographic surveys and 8 nearshore bathymetric surveys were performed between July 11, 2010, and November 4, 2011. During placement, southerly alongshore transport resulted in movement of nourishment material to the south towards the MCR North Jetty. Moderate wave conditions (significant wave height around 4 m) following the completion of the nourishment resulted in cross-shore sediment transport, with most of the nourishment material transported into the nearshore bars. The nourishment acted as a buffer to the more severe erosion, including dune overtopping and retreat, that was observed at the northern end of the study area throughout the winter. One year after placement of the nourishment, onshore transport and beach recovery were most pronounced within the permit area and to the south toward the MCR North Jetty. This suggests that there is some long-term benefit of the nourishment for reducing erosion rates locally, although the enhanced recovery also could be due to natural gradients in alongshore transport causing net movement of the sediment from north to south. Measurements made during the morphological monitoring program documented the seasonal movement and decay of nearshore sand bars. Low-energy conditions in late summer resulted in onshore bar migration early in the monitoring program. Moderate wave conditions in the autumn resulted in offshore movement of the middle bar and continued onshore migration of the outer bar. High-energy wave conditions early in the winter resulted in strong cross-shore transport and creation of a 3-bar system along portions of the coast. More southerly wave events occurred later in the winter and early spring and coincided

Field observations of nearshore bar formation

DEFF Research Database (Denmark)

Aagaard, Troels; Kroon, Aart; Greenwood, Brian

2008-01-01

  The formation of an inner nearshore bar was observed during a high-energy event at the sandy beach of Vejers, Denmark. The bar accreted in situ during surf zone conditions and the growth of the bar was associated with the development of a trough landward of the bar. Measurements of hydrodynamics...

The RUNE Experiment—A Database of Remote-Sensing Observations of Near-Shore Winds

DEFF Research Database (Denmark)

Floors, Rogier Ralph; Peña, Alfredo; Lea, Guillaume

2016-01-01

We present a comprehensive database of near-shore wind observations that were carried out during the experimental campaign of the RUNE project. RUNE aims at reducing the uncertainty of the near-shore wind resource estimates from model outputs by using lidar, ocean, and satellite observations. Here...

Spatial and temporal variations of carbonate content in the beach and nearshore environments off Goa, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Veerayya, M.

-90%) in the foreshore regions of individual beaches whereas low CaCO sub(3) (less than 20%) in the dune and backshore areas of these beaches and adjoining nearshore environs up to 10 m isobath. The observed spatial distribution shows the occurrence of modern carbonate...

Development of a wave-induced forcing threshold for nearshore impact of Wave Energy Converter arrays

Science.gov (United States)

O'Dea, A.; Haller, M. C.; Ozkan-Haller, H. T.

2016-02-01

Wave-induced forcing is a function of spatial gradients in the wave radiation stresses and is the main driver of alongshore currents, rip currents, and nearshore sediment transport. The installation of nearshore Wave Energy Converter (WEC) arrays may cause significant changes in the surf zone radiation stresses and could therefore impact nearshore littoral processes. In the first part of this study, a new threshold for nearshore hydrodynamic impact due to the presence of WEC devices is established based on changes in the alongshore radiation stress gradients shoreward of WEC arrays. The threshold is defined based on the relationship between nearshore radiation stresses and alongshore currents as observed in field data. Next, we perform a parametric study of the nearshore impact of WEC arrays using the SWAN wave model. Trials are conducted on an idealized, alongshore-uniform beach with a range of WEC array configurations, locations, and incident wave conditions, and conditions that generate radiation stress gradients above the impact threshold are identified. Finally, the same methodology is applied to two wave energy test sites off the coast of Newport, OR with more complicated bathymetries. Although the trends at the field sites are similar to those seen in the parametric study, the location and extent of the changes in the alongshore radiation stress gradients appear to be heavily influenced by the local bathymetry.

Increased sediment load during a large-scale dam removal changes nearshore subtidal communities.

Directory of Open Access Journals (Sweden)

Stephen P Rubin

Full Text Available The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx-over 10 million tonnes-during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth. Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.

Increased sediment load during a large-scale dam removal changes nearshore subtidal communities

Science.gov (United States)

Rubin, Stephen P.; Miller, Ian M.; Foley, Melissa M.; Berry, Helen D.; Duda, Jeffrey J.; Hudson, Benjamin; Elder, Nancy E.; Beirne, Matthew M.; Warrick, Jonathan; McHenry, Michael L.; Stevens, Andrew; Eidam, Emily; Ogston, Andrea; Gelfenbaum, Guy R.; Pedersen, Rob

2017-01-01

The coastal marine ecosystem near the Elwha River was altered by a massive sediment influx—over 10 million tonnes—during the staged three-year removal of two hydropower dams. We used time series of bathymetry, substrate grain size, remotely sensed turbidity, scuba dive surveys, and towed video observations collected before and during dam removal to assess responses of the nearshore subtidal community (3 m to 17 m depth). Biological changes were primarily driven by sediment deposition and elevated suspended sediment concentrations. Macroalgae, predominantly kelp and foliose red algae, were abundant before dam removal with combined cover levels greater than 50%. Where persistent sediment deposits formed, macroalgae decreased greatly or were eliminated. In areas lacking deposition, macroalgae cover decreased inversely to suspended sediment concentration, suggesting impacts from light reduction or scour. Densities of most invertebrate and fish taxa decreased in areas with persistent sediment deposition; however, bivalve densities increased where mud deposited over sand, and flatfish and Pacific sand lance densities increased where sand deposited over gravel. In areas without sediment deposition, most invertebrate and fish taxa were unaffected by increased suspended sediment or the loss of algae cover associated with it; however, densities of tubeworms and flatfish, and primary cover of sessile invertebrates increased suggesting benefits of increased particulate matter or relaxed competition with macroalgae for space. As dam removal neared completion, we saw evidence of macroalgal recovery that likely owed to water column clearing, indicating that long-term recovery from dam removal effects may be starting. Our results are relevant to future dam removal projects in coastal areas and more generally to understanding effects of increased sedimentation on nearshore subtidal benthic communities.

Morphologic Response and Sediment Redistribution of the Beach and Nearshore Sand Bars due to Extratropical and Tropical Storm Forcing: a Spatial and Temporal Analysis

Science.gov (United States)

Miselis, J. L.; McNinch, J. E.

2005-05-01

Shore-oblique bars and associated exposures of an underlying geologic stratum in the nearshore have been documented along the US East Coast and have been linked to shoreline erosional hotspots. While earlier studies acknowledged that the bedforms responded to extratropical and tropical storms, neither quantified the extent of sediment redistribution after the events. An approach that encompasses actual volume measurements across the nearshore-beach down to a non-sandy stratum and quantifies the response of the beach and the nearshore to the same hydrodynamic forcing will enable a better understanding of the exchange of sediment between the two regions. Total nearshore sediment volume has been shown to be a first-order contributor to the behavior of the shoreline. This volumetric approach is employed in the analysis of morphological changes and the redistribution of sediment in the nearshore and beach following storms. A regional survey from 2002 provides the initial, fair-weather morphologic state of the nearshore (1.5-15m water depth) spanning 40 km of the North Carolina Outer Banks. Four small-scale surveys were conducted in subsequent years, focusing on four 1-km2 regions within the initial 2002 survey area. The smaller regions were selected on the basis of the morphological state observed during the 2002 survey and historical shoreline behavior. Data were collected in March 2003 following a Northeaster; in May 2003 following an extended period of fair weather conditions; in November 2003 following Hurricane Isabel; and finally, in June 2004 after another period of fair weather. A swath bathymetry system was used to collect bathymetry and side scan sonar (acoustic backscatter) and a high-resolution chirp sub-bottom profiler imaged the shallow sub-surface geology of the nearshore. In addition, RTK-GPS was used to map the sub-aerial beach at each 1-km2 site from the toe of the dune to the water line for the May 2003, November 2003, and June 2004 sampling periods

Uranium in the Near-shore Aquatic Food Chain: Studies on Periphyton and Asian Clams

International Nuclear Information System (INIS)

Bunn, Amoret L.; Miley, Terri B.; Eslinger, Paul W.; Brandt, Charles A.; Napier, Bruce A.

2007-01-01

The benthic aquatic organisms in the near-shore environment of the Columbia River are the first biological receptors that can be exposed to groundwater contaminants coming from the U.S. Department of Energy's Hanford Site. The primary contaminant of concern in the former nuclear fuels processing area at the Site, known as the 300 Area, is uranium. Currently, there are no national clean up criteria for uranium and ecological receptors. This report summarizes efforts to characterize biological uptake of uranium in the food chain of the benthic aquatic organisms and provide information to be used in future assessments of uranium and the ecosystem.

Data on nearshore wave process and surficial beach deposits, central Tamil Nadu coast, India.

Science.gov (United States)

Joevivek, V; Chandrasekar, N

2017-08-01

The chronicles of nearshore morphology and surficial beach deposits provide valuable information about the nature of the beach condition and the depositional environment. It imparts an understanding about the spatial and temporal relationship of nearshore waves and its influence over the distribution of beach sediments. This article contains data about wave and sediment dynamics of the ten sandy beaches along the central Tamil Nadu coast, India. This present dataset comprises nearshore wave parameters, breaker wave type, beach morphodynamic state, grain size distribution and weight percentage of heavy and light mineral distribution. The dataset will figure out the beach morphology and hydrodynamic condition with respect to the different monsoonal season. This will act as a field reference to realize the coastal dynamics in an open sea condition. The nearshore entities were obtained from the intensive field survey between January 2011 and December 2011, while characteristics of beach sediments are examined by the chemical process in the laboratory environment.

Cross-Shore Environmental Gradients in the Western Mediterranean Coast and Their Influence on Nearshore Phytoplankton Communities

Directory of Open Access Journals (Sweden)

Gotzon Basterretxea

2018-04-01

Full Text Available During summer, when oligotrophic conditions prevail offshore in the Mediterranean Sea, enhanced phytoplankton stripes are often observed in nearshore waters. In this study, we examine the cross-shore hydrographic variability and the associated microbial plankton communities in this zone. Detailed cross-shore underway sampling at 47 coastal sites spread along the Balearic and Catalan coasts revealed the widespread existence of narrow bands of warm and decreased salinity water beholding high phytoplankton biomass (up to 50-fold vs. offshore chlorophyll. Most intense physical and biological anomalies along these transects were generally constrained to the first hundred meters from the shoreline (i.e., a transition zone starting at ~400 m. We use Principal Component Analysis (PCA and k-means cluster analysis to categorize temperature, salinity and chlorophyll (T, S and Chl in three main types of cross-shore trends. Prevalence of exponential-shaped Chl trends was observed particularly in areas with shoreward directed winds (B1-type. The other two trends (B2 and B3 presented variations off the coast produced by alongshore structures like river plumes, city outfalls and other features. Exponential-shaped cross-shore chlorophyll distribution (B1-type accumulated 90% of the total transect Chl variation in the first 367 ± 190 m from the shoreline, whereas this distance was variable in the other profile types. Repeated daily sampling at one site with this transect typology revealed that wind forcing variations produced fast response on cross-shore T and S properties. Chl was less sensitive to changes at this time-scale. Phytoplankton communities exhibited site-dependent responses to the nearshore environment. Pico- and nanoplankton assemblages, typically dominating coastal assemblages during summer in the Mediterranean Sea, showed lower cross-shore variation. Conversely, larger response to nearshore conditions was observed in microplankton populations

Recurrent Neural Network Modeling of Nearshore Sandbar Behavior

NARCIS (Netherlands)

Pape, L.; Ruessink, B.G.; Wiering, M.A.; Turner, I.L.

2007-01-01

The temporal evolution of nearshore sandbars (alongshore ridges of sand fringing coasts in water depths less than 10 m and of paramount importance for coastal safety) is commonly predicted using process-based models. These models are autoregressive and require offshore wave characteristics as

Detailed Characterization of Nearshore Processes During NCEX

Science.gov (United States)

Holland, K.; Kaihatu, J. M.; Plant, N.

2004-12-01

Recent technology advances have allowed the coupling of remote sensing methods with advanced wave and circulation models to yield detailed characterizations of nearshore processes. This methodology was demonstrated as part of the Nearshore Canyon EXperiment (NCEX) in La Jolla, CA during Fall 2003. An array of high-resolution, color digital cameras was installed to monitor an alongshore distance of nearly 2 km out to depths of 25 m. This digital imagery was analyzed over the three-month period through an automated process to produce hourly estimates of wave period, wave direction, breaker height, shoreline position, sandbar location, and bathymetry at numerous locations during daylight hours. Interesting wave propagation patterns in the vicinity of the canyons were observed. In addition, directional wave spectra and swash / surf flow velocities were estimated using more computationally intensive methods. These measurements were used to provide forcing and boundary conditions for the Delft3D wave and circulation model, giving additional estimates of nearshore processes such as dissipation and rip currents. An optimal approach for coupling these remotely sensed observations to the numerical model was selected to yield accurate, but also timely characterizations. This involved assimilation of directional spectral estimates near the offshore boundary to mimic forcing conditions achieved under traditional approaches involving nested domains. Measurements of breaker heights and flow speeds were also used to adaptively tune model parameters to provide enhanced accuracy. Comparisons of model predictions and video observations show significant correlation. As compared to nesting within larger-scale and coarser resolution models, the advantages of providing boundary conditions data using remote sensing is much improved resolution and fidelity. For example, rip current development was both modeled and observed. These results indicate that this approach to data-model coupling

Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

Science.gov (United States)

Swarzenski, Peter W.; Dulai, H.; Kroeger, K.D.; Smith, C.G.; Dimova, N.; Storlazzi, C. D.; Prouty, N.G.; Gingerich, S.B.; Glenn, C. R.

2016-01-01

Study regionThe study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef.Study focusCoastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore ecosystems and material budgets. A unique combined geochemical tracer and oceanographic time-series study addressed rates and oceanic forcings of submarine groundwater discharge at a submarine spring site off west Maui, Hawaii.New hydrological insights for the regionEstimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d) mass balance model. Such estimates were complemented with a novel thoron (220Rn,t1/2 = 56 s) groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

Uranium in the Near-shore Aquatic Food Chain: Studies on Periphyton and Asian Clams

Energy Technology Data Exchange (ETDEWEB)

Bunn, Amoret L.; Miley, Terri B.; Eslinger, Paul W.; Brandt, Charles A.; Napier, Bruce A.

2007-12-31

The benthic aquatic organisms in the near-shore environment of the Columbia River are the first biological receptors that can be exposed to groundwater contaminants coming from the U.S. Department of Energy's Hanford Site. The primary contaminant of concern in the former nuclear fuels processing area at the Site, known as the 300 Area, is uranium. Currently, there are no national clean up criteria for uranium and ecological receptors. This report summarizes efforts to characterize biological uptake of uranium in the food chain of the benthic aquatic organisms and provide information to be used in future assessments of uranium and the ecosystem.

Recurrent neural network modeling of nearshore sandbar behavior

NARCIS (Netherlands)

Pape, Leo; Ruessink, B.G.; Wiering, Marco A.; Turner, Ian L.

2007-01-01

The temporal evolution of nearshore sandbars (alongshore ridges of sand fringing coasts in water depths less than 10 m and of paramount importance for coastal safety) is commonly predicted using process-based models. These models are autoregressive and require offshore wave characteristics as input,

Severe impacts of brown tides caused by Sargassum spp. on near-shore Caribbean seagrass communities.

Science.gov (United States)

van Tussenbroek, Brigitta I; Hernández Arana, Héctor A; Rodríguez-Martínez, Rosa E; Espinoza-Avalos, Julio; Canizales-Flores, Hazel M; González-Godoy, Carlos E; Barba-Santos, M Guadalupe; Vega-Zepeda, Alejandro; Collado-Vides, Ligia

2017-09-15

From mid-2014 until the end of 2015, the Mexican Caribbean coast experienced a massive influx of drifting Sargassum spp. that accumulated on the shores, resulting in build-up of decaying beach-cast material and near-shore murky brown waters (Sargassum-brown-tides, Sbt). The effects of Sbt on four near-shore waters included reduction in light, oxygen (hypoxia or anoxia) and pH. The monthly influx of nitrogen, and phosphorus by drifting Sargassum spp. was estimated at 6150 and 61kgkm -1 respectively, resulting in eutrophication. Near-shore seagrass meadows dominated by Thalassia testudinum were replaced by a community dominated by calcareous rhizophytic algae and drifting algae and/or epiphytes, resulting in 61.6-99.5% loss of below-ground biomass. Near-shore corals suffered total or partial mortality. Recovery of affected seagrass meadows may take years or even decades, or changes could be permanent if massive influxes of Sargassum spp. recur. Copyright © 2017. Published by Elsevier Ltd.

Covariance Function for Nearshore Wave Assimilation Systems

Science.gov (United States)

2018-01-30

which is applicable for any spectral wave model. The four dimensional variational (4DVar) assimilation methods are based on the mathematical ...covariance can be modeled by a parameterized Gaussian function, for nearshore wave assimilation applications , the covariance function depends primarily on...SPECTRAL ACTION DENSITY, RESPECTIVELY. ............................ 5 FIGURE 2. TOP ROW: STATISTICAL ANALYSIS OF THE WAVE-FIELD PROPERTIES AT THE

A description of the nearshore fish communities in the Huron-Erie Corridor using multiple gear types

Science.gov (United States)

Francis, James T.; Chiotti, Justin A.; Boase, James C.; Thomas, Mike V.; Manny, Bruce A.; Roseman, Edward F.

2013-01-01

Great Lakes coastal wetlands provide a critical habitat for many fish species throughout their life cycles. Once home to one of the largest wetland complexes in the Great Lakes, coastal wetlands in the Huron–Erie Corridor (HEC) have decreased dramatically since the early 1900s. We characterized the nearshore fish communities at three different wetland complexes in the HEC using electrofishing, seines, and fyke nets. Species richness was highest in the Detroit River (63), followed by the St. Clair Delta (56), and Western Lake Erie (47). The nearshore fish communities in the Detroit River and St. Clair Delta consisted primarily of shiners, bluntnose minnow, centrarchids, and brook silverside, while the Western Lake Erie sites consisted of high proportions of non-native taxa including common carp, gizzard shad, goldfish, and white perch. Species richness estimates using individual-based rarefaction curves were higher when using electrofishing data compared to fyke nets or seine hauls at each wetland. Twelve fish species were captured exclusively during electrofishing assessments, while one species was captured exclusively in fyke nets, and none exclusively during seine hauls. Western Lake Erie wetlands were more indicative of degraded systems with lower species richness, lower proportion of turbidity intolerant species, and increased abundance of non-native taxa. This work highlights the importance of coastal wetlands in the HEC by capturing 69 different fish species utilizing these wetlands to fulfill life history requirements and provides insight when selecting gears to sample nearshore littoral areas.

PacIOOS Nearshore Sensor 06 (NS06): Pohnpei, Micronesia

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 08 (NS08): Koror, Palau

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 11 (NS11): Saipan, CNMI

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

The effect of tides on nearshore environmental DNA.

Science.gov (United States)

Kelly, Ryan P; Gallego, Ramón; Jacobs-Palmer, Emily

2018-01-01

We can recover genetic information from organisms of all kinds using environmental sampling. In recent years, sequencing this environmental DNA (eDNA) has become a tractable means of surveying many species using water, air, or soil samples. The technique is beginning to become a core tool for ecologists, environmental scientists, and biologists of many kinds, but the temporal resolution of eDNA sampling is often unclear, limiting the ecological interpretations of the resulting datasets. Here, in a temporally and spatially replicated field study using ca. 313 bp of eukaryotic COI mtDNA as a marker, we find that nearshore organismal communities are largely consistent across tides. Our findings suggest that nearshore eDNA from both benthic and planktonic taxa tends to be endogenous to the site and water mass sampled, rather than changing with each tidal cycle. However, where physiochemical water mass characteristics change, we find that the relative contributions of a broad range of organisms to eDNA communities shift in concert.

DEEPWATER AND NEARSHORE FOOD WEB CHARACTERIZATIONS IN LAKE SUPERIOR

Science.gov (United States)

Due to the difficulty associated with sampling deep aquatic systems, food web relationships among deepwater fauna are often poorly known. We are characterizing nearshore versus offshore habitats in the Great Lakes and investigating food web linkages among profundal, pelagic, and ...

Temperature, productivity and sediment characteristics as drivers of seasonal and spatial variations of dissolved methane in the near-shore coastal areas (Belgian coastal zone, North Sea)

Science.gov (United States)

Borges, Alberto V.; Speeckaert, Gaëlle; Champenois, Willy; Scranton, Mary I.; Gypens, Nathalie

2017-04-01

The open ocean is a modest source of CH4 to the atmosphere compared to other natural and anthropogenic CH4 emissions. Coastal regions are more intense sources of CH4 to the atmosphere than open oceanic waters, in particular estuarine zones. The CH4 emission to the atmosphere from coastal areas is sustained by riverine inputs and methanogenesis in the sediments due to high organic matter (OM) deposition. Additionally, natural gas seeps are sources of CH4 to bottom waters leading to high dissolved CH4 concentrations in bottom waters (from tenths of nmol L-1 up to several µmol L-1). We report a data set of dissolved CH4 concentrations obtained at nine fixed stations in the Belgian coastal zone (Southern North Sea), during one yearly cycle, with a bi-monthly frequency in spring, and a monthly frequency during the rest of the year. This is a coastal area with multiple possible sources of CH4 such as from rivers and gassy sediments, and where intense phytoplankton blooms are dominated by the high dimethylsulfoniopropionate (DMSP) producing micro-algae Phaeocystis globosa, leading to DMSP and dimethylsulfide (DMS) concentrations. Furthermore, the BCZ is a site of important OM sedimentation and accumulation unlike the rest of the North Sea. Spatial variations of dissolved CH4 concentrations were very marked with a minimum yearly average of 9 nmol L-1 in one of the most off-shore stations and maximum yearly average of 139 nmol L-1 at one of the most near-shore stations. The spatial variations of dissolved CH4 concentrations were related to the organic matter (OM) content of sediments, although the highest concentrations seemed to also be related to inputs of CH4 from gassy sediments associated to submerged peat. In the near-shore stations with fine sand or muddy sediments with a high OM content, the seasonal cycle of dissolved CH4 concentration closely followed the seasonal cycle of water temperature, suggesting the control of methanogenesis by temperature in these OM

Development of multi-year land cover data to assess wildfire impacts to coastal watersheds and the nearshore environment

Science.gov (United States)

Morrison, Katherine D.

In the Mediterranean ecosystems of coastal California, wildfire is a common disturbance that can significantly alter vegetation in watersheds that transport sediment and nutrients to the adjacent nearshore oceanic environment. We assess the impact of two wildfires that burned in 2008 on land cover and to the nearshore environment along the Big Sur coast in central California. We created a multi-year land cover dataset to assess changes to coastal watersheds as a result of fire. This land cover dataset was then used to model changes in nonpoint source pollutants transported to the nearshore environment. Results indicate post-fire increases in percent export compared to pre-fire years and also link wildfire severity to the specific land cover changes that subsequently increase exports of pollutants and sediment to the nearshore environment. This approach is a replicable across watersheds and also provides a framework for including the nearshore environment as a value at risk terrestrial land management revolving around wildfire, including suppression, thinning, and other activities that change land cover at a landscape scale.

Impact of Varying Wave Conditions on the Mobility of Arsenic in a Nearshore Aquifer on the Great Lakes

Science.gov (United States)

Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

2017-12-01

Groundwater-coastal water interactions play an important role in controlling the behavior of inorganic chemicals in nearshore aquifers and the subsequent flux of these chemicals to receiving coastal waters. Previous studies have shown that dynamic groundwater flows and water exchange across the sediment-water interface can set up strong geochemical gradients and an important reaction zone in a nearshore aquifer that affect the fate of reactive chemicals. There is limited understanding of the impact of transient coastal forcing such as wave conditions on groundwater dynamics and geochemistry in a nearshore aquifer. The goal of this study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer and to determine the hydrological and geochemical factors controlling its fate and ultimate delivery to receiving coastal waters. Field investigations were conducted over the period of intensified wave conditions on a freshwater beach on Lake Erie, Canada. High spatial resolution aqueous and sediment sampling was conducted to characterize the subsurface distribution of inorganic species in the nearshore aquifer. Numerical groundwater flow and transport simulations were conducted to evaluate wave-induced perturbations in the flow dynamics including characterizing changes in the groundwater flow recirculations in the nearshore aquifer. The combination of field data and numerical simulations reveal that varying wave conditions alter groundwater flows and set up geochemical transition zones within the aquifer resulting in the release and sequestration of arsenic. Interactions between oxic surface water, mildly reducing shallow groundwater, and reducing sulfur- and iron-rich deep groundwater promote dynamic iron, sulfur and manganese cycling which control the mobility of arsenic in the aquifer. The findings of this study have potential implications for the fate and transport of other reactive chemicals (e.g. phosphorus, mercury) in

Monitoring the effects of disposal of fine sediments from maintenance dredging on suspended particulate matter concentration in the Belgian nearshore area

OpenAIRE

Fettweis, M.; Baeye, M.; Francken, F.; Lauwaert, B.; Van den Eynde, D.; Van Lancker, V.; Martens, C.; Michielsen, T.

2012-01-01

The impact of continuous disposal of fine-grained sediments from maintenance dredging works on the suspended particulate matter concentration in a shallow nearshore turbidity maximum was investigated during dredging experiment (port of Zeebrugge, southern North Sea). Before, during and after the experiment monitoring of SPM concentration using OBS and ADV altimetry was carried out at a location 5 km west of the disposal site. A statistical analysis, based on the concept of populations and sub...

Monitoring plant tissue nitrogen isotopes to assess nearshore inputs of nitrogen to Lake Crescent, Olympic National Park, Washington

Science.gov (United States)

Cox, Stephen E.; Moran, Patrick W.; Huffman, Raegan L.; Fradkin, Steven C.

2016-05-31

Mats of filamentous-periphytic algae present in some nearshore areas of Lake Crescent, Olympic National Park, Washington, may indicate early stages of eutrophication from nutrient enrichment of an otherwise highly oligotrophic lake. Natural abundance ratios of stable isotopes of nitrogen (δ15N) measured in plant tissue growing in nearshore areas of the lake indicate that the major source of nitrogen used by these primary producing plants is derived mainly from atmospherically fixed nitrogen in an undeveloped forested ecosystem. Exceptions to this pattern occurred in the Barnes Point area where elevated δ15N ratios indicate that effluent from septic systems also contribute nitrogen to filamentous-periphytic algae growing in the littoral zone of that area. Near the Lyre River outlet of Lake Crescent, the δ15N of filamentous-periphytic algae growing in close proximity to the spawning areas of a unique species of trout show little evidence of elevated δ15N indicating that nitrogen from on-site septic systems is not a substantial source of nitrogen for these plants. The δ15N data corroborate estimates that nitrogen input to Lake Crescent from septic sources is comparatively small relative to input from motor vehicle exhaust and vegetative sources in undeveloped forests, including litterfall, pollen, and symbiotic nitrogen fixation. The seasonal timing of blooms of filamentous-periphytic algal near the lake shoreline is also consistent with nitrogen exported from stands of red alder trees (Alnus rubra). Isotope biomonitoring of filamentous-periphytic algae may be an effective approach to monitoring the littoral zone for nutrient input to Lake Crescent from septic sources.

The Performance of Nearshore Dredge Disposal at Ocean Beach, San Francisco, California, 2005-2007

Science.gov (United States)

Barnard, Patrick L.; Erikson, Li H.; Hansen, Jeff E.; Elias, Edwin

2009-01-01

Ocean Beach, California, contains an erosion hot spot in the shadow of the San Francisco ebb tidal delta that threatens valuable public infrastructure as well as the safe recreational use of the beach. In an effort to reduce the erosion at this location a new plan for the management of sediment dredged annually from the main shipping channel at the mouth of San Francisco Bay was implemented in May 2005 by the United States Army Corps of Engineers, San Francisco District (USACE). The USACE designated a temporary nearshore dredge disposal site for the annual disposal of about 230,000 m3 (300,000 yd3) of sand about 750 m offshore and slightly south of the erosion hot spot, in depths between approximately 9 and 14 m. The site has now been used three times for a total sediment disposal of about 690,000 m3 (about 900,000 yds3). The disposal site was chosen because it is in a location where strong tidal currents and open-ocean waves can potentially feed sediment toward the littoral zone in the reach of the beach that is experiencing critical erosion, as well as prevent further scour on an exposed outfall pipe. The onshore migration of sediment from the target disposal location might feed the primary longshore bar or the nearshore zone, and provide a buffer to erosion that peaks during winter months when large waves impact the region. The United States Geological Survey (USGS) has been monitoring and modeling the bathymetric evolution of the test dredge disposal site and the adjacent coastal region since inception in May 2005. This paper reports on the first 2.5 years of this monitoring program effort (May 2005 to December 2007) and assesses the short-term coastal response. Here are the key findings of this report: *Approximately half of the sediment that has been placed in the nearshore dredge-disposal site during the 2.5 years of this study remains within the dredge focus area. *In the winter of 2006-7, large waves transported the dredge-mound material onshore. *High

PacIOOS Nearshore Sensor 13 (NS13): Kahului, Maui, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 16 (NS16): Wailupe, Oahu, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 09 (NS09): Cetti Bay, Guam

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 15 (NS15): Pago Bay, Guam

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 07 (NS07): Majuro, Marshall Islands

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

Strongly-sheared wind-forced currents in the nearshore regions of the central Southern California Bight

Science.gov (United States)

Noble, Marlene A.; Rosenberger, Kurt; Robertson, George L.

2015-01-01

Contrary to many previous reports, winds do drive currents along the shelf in the central portion of the Southern California Bight (SCB). Winds off Huntington Beach CA are the dominant forcing for currents over the nearshore region of the shelf (water depths less than 20 m). Winds control about 50–70% of the energy in nearshore alongshelf surface currents. The wind-driven current amplitudes are also anomalously high. For a relatively weak 1 dyne/cm2 wind stress, the alongshelf surface current amplitudes in this region can reach 80 cm/s or more. Mid-depth current amplitudes for the same wind stress are around 30–40 cm/s. These wind-driven surface current amplitudes are much larger than previously measured over other nearshore shelf regions, perhaps because this program is one of the few that measured currents within a meter of the surface. The near-bed cross-shelf currents over the nearshore region of the Huntington Beach shelf have an Ekman response to winds in that they upwell (downwell) for down (up) coast winds. This response disappears further offshore. Hence, there is upwelling in the SCB, but it does not occur across the entire shelf. Subthermocline water in the nearshore region that may contain nutrients and plankton move onshore when winds are southeastward, but subthermocline water over the shelf break is not transported to the beach. The currents over the outer shelf are not predominately controlled by winds, consistent with previous reports. Instead, they are mainly driven by cross-shelf pressure gradients that are independent of local wind stress.

What is the impact on fish recruitment of anthropogenic physical and structural habitat change in shallow nearshore areas in temperate systems? : A systematic review protocol

NARCIS (Netherlands)

Macura, Biljana; Lönnstedt, Oona; Byström, Pär; Airoldi, Laura; Eriksson, Britas; Rudstam, Lars; Støttrup, Josianne

2016-01-01

Shallow nearshore marine ecosystems are changing at an increasing rate due to a range of human activities such as urbanisation and commercial development. The growing numbers of constructions and other physical and structural alterations of the shoreline often take place in nursery and spawning

Using GIS mapping of the extent of nearshore rocky reefs to estimate the abundance and reproductive output of important fishery species.

Directory of Open Access Journals (Sweden)

Jeremy T Claisse

Full Text Available Kelp Bass (Paralabrax clathratus and California Sheephead (Semicossyphus pulcher are economically and ecologically valuable rocky reef fishes in southern California, making them likely indicator species for evaluating resource management actions. Multiple spatial datasets, aerial and satellite photography, underwater observations and expert judgment were used to produce a comprehensive map of nearshore natural rocky reef habitat for the Santa Monica Bay region (California, USA. It was then used to examine the relative contribution of individual reefs to a regional estimate of abundance and reproductive potential of the focal species. For the reefs surveyed for fishes (i.e. 18 out of the 22 in the region, comprising 82% the natural rocky reef habitat 30% was produced from a relatively small proportion of the regional reef area (c. 10%. Natural nearshore rocky reefs make up only 11% of the area in the newly designated MPAs in this region, but results provide some optimism that regional fisheries could benefit through an increase in overall reproductive output, if adequate increases in size structure of targeted species are realized.

Nearshore hydrodynamics at pocket beaches with contrasting wave exposure in southern Portugal

Science.gov (United States)

Horta, João; Oliveira, Sónia; Moura, Delminda; Ferreira, Óscar

2018-05-01

Pocket beaches on rocky coasts with headlands that control hydro-sedimentary processes are considered to be constrained sedimentary systems, generally with limited sediment inputs. Pocket beaches face severe changes over time. Under worst-case scenarios, these changes can result in the loss of the beach, causing waves to directly attack adjacent cliffs. Studies of nearshore hydrodynamics can help to understand such changes and optimise sediment nourishment procedures. The present work contributes to the knowledge of hydrodynamic forcing mechanisms at pocket beaches by providing a comprehensive description of the nearshore circulation at two beaches with contrasting wave exposures. Two pocket beaches in southern Portugal were studied by combining field measurements of waves and currents with numerical models (STWAVE and BOUSS-2D). The aim of this analysis was to evaluate nearshore hydrodynamics under different wave exposure forcing conditions (e.g. variable wave heights/directions and different tidal levels). The results show that the beach circulation can rapidly shift from longshore-to rip-dominated depending on changes in both the offshore wave direction and tidal levels. Waves with higher obliquity (for both low and moderate wave energy conditions) tend to generate longshore circulation in all considered tidal stages, while waves with lower obliquity tend to produce rip flow with higher-velocity rip currents during low to intermediate tidal stages. The results indicate that the location and intensity of rip currents strongly depend on geomorphological constraints, that is, the control exerted by shore platforms. A larger morphological control is observed at mean sea level because most platforms are submerged/exposed during high/low tide and therefore exert less control on nearshore circulation.

A High Resolution Hydrodynamic Model of Puget Sound to Support Nearshore Restoration Feasibility Analysis and Design

International Nuclear Information System (INIS)

Khangaonkar, Tarang; Yang, Zhaoqing

2011-01-01

Estuarine and coastal hydrodynamic processes are sometimes neglected in the design and planning of nearshore restoration actions. Despite best intentions, efforts to restore nearshore habitats can result in poor outcomes if circulation and transport which also affect freshwater-saltwater interactions are not properly addressed. Limitations due to current land use can lead to selection of sub-optimal restoration alternatives that may result in undesirable consequences, such as flooding, deterioration of water quality, and erosion, requiring immediate remedies and costly repairs. Uncertainty with achieving restoration goals, such as recovery of tidal exchange, supply of sediment and nutrients, and establishment of fish migration pathways, may be minimized by using numerical models designed for application to the nearshore environment. A high resolution circulation and transport model of the Puget Sound, in the state of Washington, was developed to assist with nearshore habitat restoration design and analysis, and to answer the question 'can we achieve beneficial restoration outcomes at small local scale, as well as at a large estuary-wide scale?' The Puget Sound model is based on an unstructured grid framework to define the complex Puget Sound shoreline using a finite volume coastal ocean model (FVCOM). The capability of the model for simulating the important nearshore processes, such as circulation in complex multiple tidal channels, wetting and drying of tide flats, and water quality and sediment transport as part of restoration feasibility, are illustrated through examples of restoration projects in Puget Sound.

The ichthyoplankton assemblage of the Algoa Bay nearshore region ...

African Journals Online (AJOL)

The ichthyoplankton assemblage of the Algoa Bay nearshore region in relation to coastal zone utilization by juvenile fish. ... The various taxa occurring in the ichthyoplankton are discussed in terms of distribution of adults and juveniles, breeding biology and available information on early life history. The paucity of larvae of ...

Data summary for the near-shore sediment characterization task of the Clinch River Environmental Restoration Program

International Nuclear Information System (INIS)

Levine, D.A.; Hargrove, W.W.; Campbell, K.R.; Wood, M.A.; Rash, C.D.

1994-10-01

This report presents the results of the Near-Shore Sediment Characterization Task of the Clinch River Environmental Restoration Program (CR-ERP). The goals of the task were to (1) determine the extent to which near-shore surface sediments are contaminated by releases from the Oak Ridge Reservation (ORR) and (2) provide data for the Watts Bar Reservoir Interagency Permitting Group (WBRIPG) to evaluate the human health risks from exposure to sediments during and following dredging operations. The data collected for this task are also to be used in the Remedial Investigation/Feasibility Study (RLTS) for the CR-ERP operable units (Lower Watts Bar and Clinch River) to characterize the human health risk associated with exposure to near-shore sediments throughout the Watts Bar Reservoir

Nearshore currents on the southern Namaqua shelf of the Benguela upwelling system

Science.gov (United States)

Fawcett, A. L.; Pitcher, G. C.; Shillington, F. A.

2008-05-01

Nearshore currents of the southern Namaqua shelf were investigated using data from a mooring situated three and a half kilometres offshore of Lambert's Bay, downstream of the Cape Columbine upwelling cell, on the west coast of South Africa. This area is susceptible to harmful algal blooms (HABs) and wind-forced variations in currents and water column structure are critical in determining the development, transport and dissipation of blooms. Time series of local wind data, and current and temperature profile data are described for three periods, considered to be representative of the latter part of the upwelling season (27 January-22 February), winter conditions (5-29 May) and the early part of the upwelling season (10 November-12 December) in 2005. Differences observed in mean wind strength and direction between data sets are indicative of seasonal changes in synoptic meteorological conditions. These quasi-seasonal variations in wind forcing affect nearshore current flow, leading to mean northward flow in surface waters early in the upwelling season when equatorward, upwelling-favourable winds are persistent. Mean near-surface currents are southward during the latter part of the upwelling season, consistent with more prolonged periods of relaxation from equatorward winds, and under winter conditions when winds were predominantly poleward. Within these seasonal variations in mean near-surface current direction, two scales of current variability were evident within all data sets: strong inertial oscillations were driven by diurnal winds and introduced vertical shear into the water column enhancing mixing across the thermocline, while sub-inertial current variability was driven by north-south wind reversals at periods of 2-5 days. Sub-inertial currents were found to lag wind reversals by approximately 12 h, with a tendency for near-surface currents to flow poleward in the absence of wind forcing. Consistent with similar sites along the Californian and Iberian coasts

Fate and effects of nearshore discharges of OCS produced waters. Volume 2. Technical report (Final)

International Nuclear Information System (INIS)

Rabalais, N.N.; McKee, B.A.; Reed, D.J.; Means, J.C.

1991-06-01

While the number of facilities that discharge OCS produced waters into coastal environments of Louisiana are few in number, they account for large volumes, individually and collectively. Of the 15 facilities which discharge OCS-generated produced water into coastal environments of Louisiana (as of February 1990), 10 discharges in seven areas were studied. The discharge volumes of the study areas range from 3,000 to 106,000/bbl.d. The receiving environments for these effluents are varied, but include the shallow, nearshore continental shelf; high energy, freshwater distributaries of the Mississippi River delta; and brackish and saline coastal environments with moderately to poorly flushed waters. All study areas are within the Mississippi River Deltaic Plain. The study expanded on the initial assessment of Boesch and Rabalais (1989a) with increased temporal and spatial studies of three areas, additional study sites including an abandoned discharge, and additional analytical and field observations

Nearshore regional behavior of lightning interaction with wind turbines

Directory of Open Access Journals (Sweden)

Gilbert A. Malinga

2016-01-01

Full Text Available The severity of lightning strikes on offshore wind turbines built along coastal and nearshore regions can pose safety concerns that are often overlooked. In this research study the behavior of electrical discharges for wind turbines that might be located in the nearshore regions along the East Coast of China and Sea of Japan were characterized using a physics-based model that accounted for a total of eleven different geometrical and lightning parameters. Utilizing the electrical potential field predicted using this model it was then possible to estimate the frequency of lightning strikes and the distribution of electrical loads utilizing established semi-empirical relationships and available data. The total number of annual lightning strikes on an offshore wind turbine was found to vary with hub elevation, extent of cloud cover, season and geographical location. The annual lightning strike rate on a wind turbine along the nearshore region on the Sea of Japan during the winter season was shown to be moderately larger compared to the lightning strike frequency on a turbine structure on the East Coast of China. Short duration electrical discharges, represented using marginal probability functions, were found to vary with season and geographical location, exhibiting trends consistent with the distribution of the electrical peak current. It was demonstrated that electrical discharges of moderately long duration typically occur in the winter months on the East Coast of China and the summer season along the Sea of Japan. In contrast, severe electrical discharges are typical of summer thunderstorms on the East Coast of China and winter frontal storm systems along the West Coast of Japan. The electrical charge and specific energy dissipated during lightning discharges on an offshore wind turbine was found to vary stochastically, with severe electrical discharges corresponding to large electrical currents of long duration.

Variability In Long-Wave Runup as a Function of Nearshore Bathymetric Features

Energy Technology Data Exchange (ETDEWEB)

Dunkin, Lauren McNeill [Texas A & M Univ., College Station, TX (United States)

2010-05-01

Beaches and barrier islands are vulnerable to extreme storm events, such as hurricanes, that can cause severe erosion and overwash to the system. Having dunes and a wide beach in front of coastal infrastructure can provide protection during a storm, but the influence that nearshore bathymetric features have in protecting the beach and barrier island system is not completely understood. The spatial variation in nearshore features, such as sand bars and beach cusps, can alter nearshore hydrodynamics, including wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regions to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect infrastructure. In this thesis, long-wave runup variation due to changing bathymetric features as determined with the numerical model XBeach is quantified (eXtreme Beach behavior model). Wave heights are analyzed to determine the energy through the surfzone. XBeach assumes that coastal erosion at the land-sea interface is dominated by bound long-wave processes. Several hydrodynamic conditions are used to force the numerical model. The XBeach simulation results suggest that bathymetric irregularity induces significant changes in the extreme long-wave runup at the beach and the energy indicator through the surfzone.

PacIOOS Nearshore Sensor 10 (NS10): Maunalua Bay, Oahu, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 05 (NS05): Pago Pago, American Samoa

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 04 (NS04): Waikiki Aquarium, Oahu, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

Near-Shore Floating Wave Energy Converters

DEFF Research Database (Denmark)

Ruol, Piero; Zanuttigh, Barbara; Martinelli, Luca

2011-01-01

and transmission characteristics are approximated to functions of wave height, period and obliquity. Their order of magnitude are 20% and 80%, respectively. It is imagined that an array of DEXA is deployed in front of Marina di Ravenna beach (IT), a highly touristic site of the Adriatic Coast. Based on the CERC......Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency...

Native Shellfish in Nearshore Ecosystems of Puget Sound

Science.gov (United States)

2006-04-01

California Dungeness crabs (Cancer magister). California Fish and Game 63:43-51. Griffin, K. 1997. Commercial oyster cultivation and eelgrass...A.M. 2007. Great Blue Herons in Puget Sound. Puget Sound Nearshore Partnership Report No. 2007-06. Published by Seattle District, U.S. Army Corps of...non-native Pacific oyster, but more than $40 million is from native crabs , clams, and mussels. Recreationally, personal harvest of shellfish is a

Patterns of Hits to the Nearshore from a Major Fairway in the Gulf of Finland

Science.gov (United States)

Viikmae, B.; Soomere, T.

2012-04-01

The Baltic Sea hosts one of the heaviest ship traffic in the world. Although relatively small in size, still up to 15% of the world's cargo is transported along its numerous fairways. The largest threat to the environment is oil transportation that has increased more than by a factor of two in 2000-2008 and a 40% increase is expected by the year 2015. One of the major marine highways in the European waters enters the Baltic Sea through the Danish Straits, crosses the Baltic Proper and stretches through the Gulf of Finland to Saint Petersburg. An area that is highly vulnerable to ship pollution is the nearshore that usually has the largest ecological value. While the probability of coastal pollution for open ocean coasts can be reduced by shifting ship routes farther offshore, the problem for narrow bays, like the Gulf of Finland, is how to minimize the probability of hitting any of the coasts. To a certain extent, light can be shed to this problem by means of quantification of the offshore areas in terms of their ability to serve a danger to coastal environment if pollution would happen in these areas. A convenient way to address this problem is to use statistical analysis of a large number of Lagrangian trajectories of test particles representing the potential pollution and passively carried by surface currents. In this paper, we make and attempt to quantify the link between potential sources of pollution along an existing fairway and the sections of the coast reached by current-driven pollution. The problem is analysed by means of considering hits to the nearshore from a major fairway in the Gulf of Finland and by making sure whether certain parts of the coast are hit by pollution particles most frequently and whether or not these pollution particles stem from certain specific parts of the fairway. Trajectories are simulated in the Gulf of Finland by placing tracers among a line that follows one of the major fairways from the Baltic Proper to Saint Petersburg

Benthic foraminifera baseline assemblages from a coastal nearshore reef complex on the central Great Barrier Reef

Science.gov (United States)

Johnson, Jamie; Perry, Chris; Smithers, Scott; Morgan, Kyle

2016-04-01

Declining water quality due to river catchment modification since European settlement (c. 1850 A.D.) represents a major threat to the health of coral reefs on Australia's Great Barrier Reef (GBR), particularly for those located in the coastal waters of the GBR's inner-shelf. These nearshore reefs are widely perceived to be most susceptible to declining water quality owing to their close proximity to river point sources. Despite this, nearshore reefs have been relatively poorly studied with the impacts and magnitudes of environmental degradation still remaining unclear. This is largely due to ongoing debates concerning the significance of increased sediment yields against naturally high background sedimentary regimes. Benthic foraminifera are increasingly used as tools for monitoring environmental and ecological change on coral reefs. On the GBR, the majority of studies have focussed on the spatial distributions of contemporary benthic foraminiferal assemblages. While baseline assemblages from other environments (e.g. inshore reefs and mangroves) have been described, very few records exist for nearshore reefs. Here, we present preliminary results from the first palaeoecological study of foraminiferal assemblages of nearshore reefs on the central GBR. Cores were recovered from the nearshore reef complex at Paluma Shoals using percussion techniques. Recovery was 100%, capturing the entire Holocene reef sequence of the selected reef structures. Radiocarbon dating and subsequent age-depth modelling techniques were used to identify reef sequences pre-dating European settlement. Benthic foraminifera assemblages were reconstructed from the identified sequences to establish pre-European ecological baselines with the aim of providing a record of foraminiferal distribution during vertical reef accretion and against which contemporary ecological change may be assessed.

Modeling the impacts of wildfire on runoff and pollutant transport from coastal watersheds to the nearshore environment.

Science.gov (United States)

Morrison, Katherine D; Kolden, Crystal A

2015-03-15

Wildfire is a common disturbance that can significantly alter vegetation in watersheds and affect the rate of sediment and nutrient transport to adjacent nearshore oceanic environments. Changes in runoff resulting from heterogeneous wildfire effects are not well-understood due to both limitations in the field measurement of runoff and temporally-limited spatial data available to parameterize runoff models. We apply replicable, scalable methods for modeling wildfire impacts on sediment and nonpoint source pollutant export into the nearshore environment, and assess relationships between wildfire severity and runoff. Nonpoint source pollutants were modeled using a GIS-based empirical deterministic model parameterized with multi-year land cover data to quantify fire-induced increases in transport to the nearshore environment. Results indicate post-fire concentration increases in phosphorus by 161 percent, sediments by 350 percent and total suspended solids (TSS) by 53 percent above pre-fire years. Higher wildfire severity was associated with the greater increase in exports of pollutants and sediment to the nearshore environment, primarily resulting from the conversion of forest and shrubland to grassland. This suggests that increasing wildfire severity with climate change will increase potential negative impacts to adjacent marine ecosystems. The approach used is replicable and can be utilized to assess the effects of other types of land cover change at landscape scales. It also provides a planning and prioritization framework for management activities associated with wildfire, including suppression, thinning, and post-fire rehabilitation, allowing for quantification of potential negative impacts to the nearshore environment in coastal basins. Copyright © 2014 Elsevier Ltd. All rights reserved.

Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

Science.gov (United States)

Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

2014-01-01

Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

Effect of transient wave forcing on the behavior of arsenic in a sandy nearshore aquifer

Science.gov (United States)

Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

2016-12-01

Waves cause large quantities of coastal water to recirculate across the groundwater-coastal water interface in addition to inducing complex groundwater flows in the nearshore aquifer. Due to the distinct chemical composition of recirculating coastal water compared with discharging terrestrial groundwater, wave-induced recirculations and flows can alter geochemical gradients in the nearshore aquifer which may subsequently affect the mobilization and transport of reactive pollutants (e.g., arsenic). The impact of seasonal geochemical and hydrological variability on the occurrence and mobility of arsenic near the groundwater-surface water interface has been shown previously in riverine settings, however, the impact of high frequency geochemical variations (e.g., varying wave conditions) on arsenic mobility in groundwater-surface water environments is unclear. The objective of the study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer to determine the factors regulating its mobility and transport to receiving coastal waters. Field investigations were conducted at a permeable beach on the Great Lakes during a period of intensified wave conditions (wave event). High spatial resolution pore water sampling captured the geochemical conditions in the nearshore aquifer prior to the wave event, immediately after the wave event and over a recovery period of 3 weeks following the wave event. Shifts in pH and redox potential (ORP) gradients in response to varying wave conditions caused shifts in the iron and arsenic distributions in the aquifer. Sediment analysis was combined with the pore water distributions to assess the release of sediment-bound arsenic in response to the varying wave conditions. Insight into the effect of transient forcing on arsenic mobility and transport in groundwater-surface water environments is important for evaluating the potential risks associated with this toxic metalloid. The findings of this

PacIOOS Nearshore Sensor 03 (NS03): Hilton Hawaiian Pier, Oahu, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 01 (NS01): Waikiki Yacht Club, Oahu, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 02 (NS02): Hawaii Yacht Club, Oahu, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

PacIOOS Nearshore Sensor 12 (NS12): Kalama Beach Park, Maui, Hawaii

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The nearshore sensors are part of the Pacific Islands Ocean Observing System (PacIOOS) and are designed to measure a variety of ocean parameters at fixed point...

Study on the influence of the distance to shore for a wave energy farm operating in the central part of the Portuguese nearshore

International Nuclear Information System (INIS)

Rusu, Eugen; Onea, Florin

2016-01-01

Graphical abstract: Nearshore impact of the wave farm (significant wave height fields and wave vectors). Conditions for a wave farm operating at 7 km from the shore, where: (a) average conditions for total time; (b) average conditions for winter time; (c) high energy non storm conditions. (MA) – Moderate absoption, (HA) – High absorption. - Highlights: • The coastal influence of a generic wave farm is assessed. • The target area is located in the central part of Portugal. • The wave decay down wave the farm is evaluated. • The impact on the coastal circulation is also assessed. - Abstract: The objective of the present work is to assess the coastal impact induced by a generic wave farm operating in the central part of the Portuguese continental coastal environment, south of Lisbon. In order to identify better the most relevant wave patterns in the target area, two data sets were processed and analyzed. The first is represented by the ‘in situ’ measurements provided by the Sines buoy, which operates in the immediate vicinity south of the target area, and the second consists in the wave data coming from the European Centre for Medium-Range Weather Forecasts, in a point located offshore close to the target area. Three scenarios were considered for the numerical simulations that were carried out with a computational framework combining a wave and a circulation model. A generic wave farm was defined in the computational domain considering various distances from the shore: 1 km, 4 km and 7 km, respectively. In the first part of the work, the down-wave effect of the farm was evaluated taking into account the local wave characteristics in the target area and analyzing various wave parameters, as for example the wave power, wave height and mean wave direction. In the second part of the work, the influence of the farm on the nearshore circulation was also assessed. Based on the results of the present work it can be concluded that the nearshore impact of such a

Changes in nearshore waves during the active sea/land breeze period off Vengurla, central west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Amrutha, M.M.; SanilKumar, V.; Singh, J.

zones with use of mechanized boats and this area is also extensively used for tourism-related activities. Therefore, it is important to un- derstand the changes in wave parameters during the active land/sea breeze system in the nearshore region... and interaction. The wave computations in Delft3D-wave are stable due to the fully implicit schemes that have been implemented. In the Delft3D-wave module, the governing equation of wave transformation is based on action balance spectrum, in ge- ographical space...

Hierarchical multi-scale classification of nearshore aquatic habitats of the Great Lakes: Western Lake Erie

Science.gov (United States)

McKenna, J.E.; Castiglione, C.

2010-01-01

Classification is a valuable conservation tool for examining natural resource status and problems and is being developed for coastal aquatic habitats. We present an objective, multi-scale hydrospatial framework for nearshore areas of the Great Lakes. The hydrospatial framework consists of spatial units at eight hierarchical scales from the North American Continent to the individual 270-m spatial cell. Characterization of spatial units based on fish abundance and diversity provides a fish-guided classification of aquatic areas at each spatial scale and demonstrates how classifications may be generated from that framework. Those classification units then provide information about habitat, as well as biotic conditions, which can be compared, contrasted, and hierarchically related spatially. Examples within several representative coastal or open water zones of the Western Lake Erie pilot area highlight potential application of this classification system to management problems. This classification system can assist natural resource managers with planning and establishing priorities for aquatic habitat protection, developing rehabilitation strategies, or identifying special management actions.

Report on data from the Nearshore Sediment Transport Study experiment at Leadbetter Beach, Santa Barbara, California, January-February 1980 (NODC Accession 8200080)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — THIS DATA SET CONSISTS OF THE RESULTS OF THE NEARSHORE SEDIMENT Nearshore Sediment Transport Study at Leadbetter Beach, Santa Barbara, California. These data from 28...

Production and associations of zooplankton in estuarine and nearshore waters of Goa

Digital Repository Service at National Institute of Oceanography (India)

Nair, V.R.

Zooplankton production in the Zuari and Mandovi estuaries indicated 2 peaks-one in November and another in March/April. In the nearshore waters very high value of zooplankton biomass was observed in April associated with Trichodesmium bloom. Mean...

Monitoring the effects of disposal of fine sediments from maintenance dredging on suspended particulate matter concentration in the Belgian nearshore area (southern North Sea)

OpenAIRE

Fettweis, M.; Baeye, M.; Francken, F.; Lauwaert, B.; Van den Eynde, D.; Van Lancker, V.; Martens, C.; Michielsen, T.

2011-01-01

The impact of continuous disposal of fine-grained sediments from maintenance dredging works on the suspended particulate matter concentration in a shallow nearshore turbidity maximum was investigated during dredging experiment (port of Zeebrugge, southern North Sea). Before, during and after the experiment monitoring of SPM concentration using OBS and ADV altimetry was carried out at a location 5 km west of the disposal site. A statistical analysis, based on the concept of populations and sub...

Evaluation of trophic state and plankton abundance from the environmental parameters of Visakhapatnam Harbour and near-shore waters, east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Tripathy, S.C.; KusumaKumari, B.A.V.L.; Sarma, V.V.; Murty, T.V.R.

The present work describes the nutrient indices of the Visakhapatnam harbour and near-shore waters. The inner channels of Visakhapatnam harbour are considered to be eutrophic while near-shore waters (coastal and inshore waters) associated...

Impact of environmental factors on recruitment and hatching patterns of Horse Mackerel (L. collected in a nearshore rocky reef system

Directory of Open Access Journals (Sweden)

Maria Klein

2015-11-01

Full Text Available Horse mackerel (Trachurus trachurus, Linnaeus, 1758 is a highly exploited fish species, common throughout the North-East Atlantic. As a pelagic-neritic fish it typically occurs over the shelf at 100-200 m depth on sandy bottom and most research has focused on adults or early life stages (eggs and larvae, caught or examined in deeper waters. Nevertheless, larvae and early stages of Trachurus species have been observed in the nearshore environment of a rocky reef system in Portugal. More research is needed in order to understand the importance of nearshore environments for horse mackerel. In addition little is known on how environmental processes might affect early life parameters of this species. In this study we monitored the arrival of early juvenile horse mackerel to the reef environment at a fine time scale, and analyzed the relationship of environmental factors with patterns of recruitment and hatching, revealed by otolith microstructure analysis. In total around 2500 fish were collected with Standard Monitoring Units for the Recruitment of Fish (SMURF and a distinct depth preference was recorded as 99% of fish were sampled with surface SMURFs. A GAM and GAMM analysis of the recruitment and hatching pattern, respectively, revealed a strong relationship with the lunar cycle and local up-welling. Both recruitment and hatching had a periodic pattern with peaks near the new moon; upwelling had a negative impact. Further, the study indicated that the nearshore environment might be an important nursery area for the post-larval growth of horse mackerel.

Pressure-gradient-driven nearshore circulation on a beach influenced by a large inlet-tidal shoal system

Science.gov (United States)

Shi, F.; Hanes, D.M.; Kirby, J.T.; Erikson, L.; Barnard, P.; Eshleman, J.

2011-01-01

The nearshore circulation induced by a focused pattern of surface gravity waves is studied at a beach adjacent to a major inlet with a large ebb tidal shoal. Using a coupled wave and wave-averaged nearshore circulation model, it is found that the nearshore circulation is significantly affected by the heterogeneous wave patterns caused by wave refraction over the ebb tidal shoal. The model is used to predict waves and currents during field experiments conducted near the mouth of San Francisco Bay and nearby Ocean Beach. The field measurements indicate strong spatial variations in current magnitude and direction and in wave height and direction along Ocean Beach and across the ebb tidal shoal. Numerical simulations suggest that wave refraction over the ebb tidal shoal causes wave focusing toward a narrow region at Ocean Beach. Due to the resulting spatial variation in nearshore wave height, wave-induced setup exhibits a strong alongshore nonuniformity, resulting in a dramatic change in the pressure field compared to a simulation with only tidal forcing. The analysis of momentum balances inside the surf zone shows that, under wave conditions with intensive wave focusing, the alongshore pressure gradient associated with alongshore nonuniform wave setup can be a dominant force driving circulation, inducing heterogeneous alongshore currents. Pressure-gradient- forced alongshore currents can exhibit flow reversals and flow convergence or divergence, in contrast to the uniform alongshore currents typically caused by tides or homogeneous waves.

Wave-induced nearshore flow patterns in the vicinity of Cochin harbour, India

Digital Repository Service at National Institute of Oceanography (India)

PrasannaKumar, S.; Vethamony, P.; Murty, C.S.

. Anonymous, Nearshore processes along the Silver Strand littoral cell. Design Memorandum No. 4. US Army Corps of Engineers, Los Angeles, 1974, 71 pp. 15. Prasanna Kumar, S., Shenoi, S. S. C. & Kurup, P. G., Littoral drift along shoreline between Munambam...

Nearshore marine benthic invertebrates moving north along the U.S. Atlantic coast

Science.gov (United States)

Numerous species have shifted their ranges north in response to global warming. We examined 21 years (1990-2010) of marine benthic invertebrate data from the National Coastal Assessment’s monitoring of nearshore waters along the US Atlantic coast. Data came from three bioge...

Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

Directory of Open Access Journals (Sweden)

P.W. Swarzenski

2017-06-01

New hydrological insights for the region: Estimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d mass balance model. Such estimates were complemented with a novel thoron (220Rn, t1/2 = 56 s groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

Nearshore Benthic Habitats of Timor-Leste Derived from WorldView-2 Satellite Imagery

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Benthic habitat classes were derived for nearshore waters (< 20 m depths) around Timor-Leste from DigitalGlobe WorldView-2 satellite imagery, acquired from Jan 26...

Remote sensing of Qatar nearshore habitats with perspectives for coastal management.

Science.gov (United States)

Warren, Christopher; Dupont, Jennifer; Abdel-Moati, Mohamed; Hobeichi, Sanaa; Palandro, David; Purkis, Sam

2016-04-30

A framework is proposed for utilizing remote sensing and ground-truthing field data to map benthic habitats in the State of Qatar, with potential application across the Arabian Gulf. Ideally the methodology can be applied to optimize the efficiency and effectiveness of mapping the nearshore environment to identify sensitive habitats, monitor for change, and assist in management decisions. The framework is applied to a case study for northeastern Qatar with a key focus on identifying high sensitivity coral habitat. The study helps confirm the presence of known coral and provides detail on a region in the area of interest where corals have not been previously mapped. Challenges for the remote sensing methodology associated with natural heterogeneity of the physical and biological environment are addressed. Recommendations on the application of this approach to coastal environmental risk assessment and management planning are discussed as well as future opportunities for improvement of the framework. Copyright © 2015 Elsevier Ltd. All rights reserved.

AFSC/REFM: Nearshore fish survey in northern Bristol Bay, Alaska, July-August 2009

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The project consisted of a nearshore fish, invertebrate, and habitat survey in northern Bristol Bay, Alaska. A 32-ft. gillnet vessel, the F/V Willow was chartered...

Biomass and composition of zooplankton in the nearshore waters of Thal, Maharashtra

Digital Repository Service at National Institute of Oceanography (India)

Nair, V.R.; Gajbhiye, S.N; Krishnakumari, L; Desai, B.N

Biomass and composition of zooplankton in the nearshore waters of Thal, Maharashtra, India were studied at 9 stations during Feb. 1980 to Jan. 1981. The recorded variation in zooplankton biomass was 4.8-80.6 ml.(100 m super(3))/1 [av. 22.9 ml.(100 m...

A conceptual framework for Lake Michigan coastal/nearshore ecosystems, with application to Lake Michigan Lakewide Management Plan (LaMP) objectives

Science.gov (United States)

Seelbach, Paul W.; Fogarty, Lisa R.; Bunnell, David Bo; Haack, Sheridan K.; Rogers, Mark W.

2013-01-01

The Lakewide Management Plans (LaMPs) within the Great Lakes region are examples of broad-scale, collaborative resource-management efforts that require a sound ecosystems approach. Yet, the LaMP process is lacking a holistic framework that allows these individual actions to be planned and understood within the broader context of the Great Lakes ecosystem. In this paper we (1) introduce a conceptual framework that unifies ideas and language among Great Lakes managers and scientists, whose focus areas range from tributary watersheds to open-lake waters, and (2) illustrate how the framework can be used to outline the geomorphic, hydrologic biological, and societal processes that underlie several goals of the Lake Michigan LaMP, thus providing a holistic and fairly comprehensive roadmap for tackling these challenges. For each selected goal, we developed a matrix that identifies the key ecosystem processes within the cell for each lake zone and each discipline; we then provide one example where a process is poorly understood and a second where a process is understood, but its impact or importance is unclear. Implicit in these objectives was our intention to highlight the importance of the Great Lakes coastal/nearshore zone. Although the coastal/nearshore zone is the important linkage zone between the watershed and open-lake zones—and is the zone where most LaMP issues are focused--scientists and managers have a relatively poor understanding of how the coastal/nearshore zone functions. We envision follow-up steps including (1) collaborative development of a more detailed and more complete conceptual model of how (and where) identified processes are thought to function, and (2) a subsequent gap analysis of science and monitoring priorities.

Concentration and toxicity of some metals in zooplankton from nearshore waters of Bombay

Digital Repository Service at National Institute of Oceanography (India)

Gajbhiye, S.N.; Nair, V.R.; Narvekar, P.V.; Desai, B.N.

Zooplankton samples collected from 4 stations located in the nearshore waters of Bombay were analysed for Cu, Co, Mn, Ni and Cd. Concentrations of Co, Mn and Ni were more in copepods and gelatinous organisms than in mysids and decapods. High...

Diurnal variation of phytoplankton pigments and population in the nearshore waters off Thal (Maharashtra)

Digital Repository Service at National Institute of Oceanography (India)

JiyalalRam, M.J.; Desai, B.N.; Abidi, S.A.H.

with high tide. The number of phytoplankton species was maximum during day time at the offshore station whereas minimum number of species was obtained at the nearshore station. Pleurosigma, Coscinodiscus, Nitzschia, Navicula, Thalassionema, Thalassiothrix...

Sources and sinks of microplastics in Canadian Lake Ontario nearshore, tributary and beach sediments.

Science.gov (United States)

Ballent, Anika; Corcoran, Patricia L; Madden, Odile; Helm, Paul A; Longstaffe, Fred J

2016-09-15

Microplastics contamination of Lake Ontario sediments is investigated with the aim of identifying distribution patterns and hotspots in nearshore, tributary and beach depositional environments. Microplastics are concentrated in nearshore sediments in the vicinity of urban and industrial regions. In Humber Bay and Toronto Harbour microplastic concentrations were consistently >500 particles per kg dry sediment. Maximum concentrations of ~28,000 particles per kg dry sediment were determined in Etobicoke Creek. The microplastic particles were primarily fibres and fragments microplastics in terms of how and where to implement preventative measures to reduce the contaminant influx. Although the impacts of microplastics contamination on ecosystem health and functioning is uncertain, understanding, monitoring and preventing further microplastics contamination in Lake Ontario and the other Great Lakes is crucial. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of bathymetric filtering on nearshore process model results

Science.gov (United States)

Plant, N.G.; Edwards, K.L.; Kaihatu, J.M.; Veeramony, J.; Hsu, L.; Holland, K.T.

2009-01-01

Nearshore wave and flow model results are shown to exhibit a strong sensitivity to the resolution of the input bathymetry. In this analysis, bathymetric resolution was varied by applying smoothing filters to high-resolution survey data to produce a number of bathymetric grid surfaces. We demonstrate that the sensitivity of model-predicted wave height and flow to variations in bathymetric resolution had different characteristics. Wave height predictions were most sensitive to resolution of cross-shore variability associated with the structure of nearshore sandbars. Flow predictions were most sensitive to the resolution of intermediate scale alongshore variability associated with the prominent sandbar rhythmicity. Flow sensitivity increased in cases where a sandbar was closer to shore and shallower. Perhaps the most surprising implication of these results is that the interpolation and smoothing of bathymetric data could be optimized differently for the wave and flow models. We show that errors between observed and modeled flow and wave heights are well predicted by comparing model simulation results using progressively filtered bathymetry to results from the highest resolution simulation. The damage done by over smoothing or inadequate sampling can therefore be estimated using model simulations. We conclude that the ability to quantify prediction errors will be useful for supporting future data assimilation efforts that require this information.

Wave-induced nearshore circulation along the Calangute-Candolim beach, Goa, West coast of India

Digital Repository Service at National Institute of Oceanography (India)

Krishnakumar, V.; Murty, C.S.; Heblekar, A.K.

The wave-induced nearshore circulation model suggested by Noda has been modified and applied for three small segments along the coast of Goa. The present model incorporates the prevailing bottom topography and considers its variation along...

Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water

Science.gov (United States)

Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.

2012-01-01

Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s–1). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731–6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

Walrus areas of use in the Chukchi Sea during sparse sea ice cover

Science.gov (United States)

Jay, Chadwick V.; Fischbach, Anthony S.; Kochnev, Anatoly A.

2012-01-01

The Pacific walrus Odobenus rosmarus divergens feeds on benthic invertebrates on the continental shelf of the Chukchi and Bering Seas and rests on sea ice between foraging trips. With climate warming, ice-free periods in the Chukchi Sea have increased and are projected to increase further in frequency and duration. We radio-tracked walruses to estimate areas of walrus foraging and occupancy in the Chukchi Sea from June to November of 2008 to 2011, years when sea ice was sparse over the continental shelf in comparison to historical records. The earlier and more extensive sea ice retreat in June to September, and delayed freeze-up of sea ice in October to November, created conditions for walruses to arrive earlier and stay later in the Chukchi Sea than in the past. The lack of sea ice over the continental shelf from September to October caused walruses to forage in nearshore areas instead of offshore areas as in the past. Walruses did not frequent the deep waters of the Arctic Basin when sea ice retreated off the shelf. Walruses foraged in most areas they occupied, and areas of concentrated foraging generally corresponded to regions of high benthic biomass, such as in the northeastern (Hanna Shoal) and southwestern Chukchi Sea. A notable exception was the occurrence of concentrated foraging in a nearshore area of northwestern Alaska that is apparently depauperate in walrus prey. With increasing sea ice loss, it is likely that walruses will increase their use of coastal haul-outs and nearshore foraging areas, with consequences to the population that are yet to be understood.

The tidal influence on oil and gas emissions from an abandoned oil well: Nearshore Summerland, California

International Nuclear Information System (INIS)

Leifer, Ira; Wilson, Ken

2007-01-01

Oil and gas emissions were quantified for natural and human sources in nearshore waters off Summerland, California through deployment of custom designed collection tents. Seepage was measured at a repeatedly abandoned well, on the seabed from a caisson located along the historical location of the Treadwell Wharf, where the world's first off-shore oil wells were drilled at the end of the 19th century. Seepage rates at the capped T-10 Well, located in ∼5 m water, showed high correlation to tides. Site emissions were 2.4 and 38.7 L day -1 oil and gas, respectively. Emissions were measured from two areas of seepage at the T-10 Well Site. Oil and gas ratios were inversely correlated between the two seepage areas, demonstrating connectivity. Data were interpreted in terms of an electronic circuit model of seepage with respect to the time lag between local low tide and peak oil emissions

Nearshore and offshore environmental effects monitoring at the Sable Offshore Energy project

International Nuclear Information System (INIS)

Hurley, G. V.

2000-01-01

A monitoring program to determine whether any temporary or permanent environmental perturbations may be attributable to the Sable offshore gas pipeline project as it approaches landfall at Goldboro through an outer bay is discussed, This nearshore region is an active fishing region for the residents of Goldboro, hence the concern about possible contamination. The monitoring project began with a baseline study, followed by monitoring the construction and the recovery period following construction, to ensure that any persistent changes to the nearshore aquatic environment were documented. The monitoring study included representatives of the fishing community to ensure that concerns are addressed early and on a continuing basis. At various phases of the project water properties,sediment modelling, the effects of construction on sea bottom conditions, benthic biota and cultivated mussels, water quality, phytoplankton, and resuspension of toxic cysts, terns and other seabirds were studied. Monitoring programs were also established for sea urchins and mussels, two important commercial species. Commercial-sized sea urchins showed a decrease of 60 per cent between 1998 and 1999 (i.e. the construction period). Recovery of sea urchin population in the immediate trench region will be the special focus of the post-construction monitoring phase. Mussel spat settlement and mussel tissue condition, lobster trapping, water properties, and bird behaviour showed no measurable changes during construction monitoring. In addition to these studies there is an ongoing offshore monitoring program in effect by Sable Offshore Energy Inc., put in place as a condition of approval of its Development Plan by the Canada-Nova Scotia Offshore Petroleum Board. This program monitors attributes such as water quality, suspended particulate matter in the benthic boundary layer, sediment quality, the benthic habitat and megafaunal community, shellfish body burden and taint, marine mammals and seabirds

Hydrodynamic Modeling Analysis to Support Nearshore Restoration Projects in a Changing Climate

Directory of Open Access Journals (Sweden)

Zhaoqing Yang

2014-01-01

Full Text Available To re-establish the intertidal wetlands with full tidal exchange and improve salmonid rearing habitat in the Skagit River estuary, State of Washington, USA, a diked agriculture farm land along the Skagit Bay front is proposed to be restored to a fully functional tidal wetland. The complex and dynamic Skagit River estuarine system calls for the need of a multi-facet and multi-dimensional analysis using observed data, numerical and analytical methods. To assist the feasibility study of the restoration project, a hydrodynamic modeling analysis was conducted using a high-resolution unstructured-grid coastal ocean model to evaluate the hydrodynamic response to restoration alternatives and to provide guidance to the engineering design of a new levee in the restoration site. A set of parameters were defined to quantify the hydrodynamic response of the nearshore restoration project, such as inundation area, duration of inundation, water depth and salinity of the inundated area. To assist the design of the new levee in the restoration site, the maximum water level near the project site was estimated with consideration of extreme high tide, wind-induced storm surge, significant wave height and future sea-level rise based on numerical model results and coastal engineering calculation.

Near-shore wind power - protected seascapes, environmentalists' attitudes, and the technocratic planning perspective

NARCIS (Netherlands)

Wolsink, M.

2010-01-01

In contested wind farm developments, the dominant issue concerns scenic impact and the landscape at the proposed site. The number of large wind power schemes that have failed is growing. The case analysed here is a near-shore wind farm in the Dutch part of the Wadden Sea, in 2001 the largest wind

Terrestrial and marine trophic pathways support young-of-year growth in a nearshore Arctic fish

Science.gov (United States)

von Biela, Vanessa R.; Zimmerman, Christian E.; Cohn, Brian R.; Welker, Jeffrey M.

2013-01-01

River discharge supplies nearshore communities with a terrestrial carbon source that is often reflected in invertebrate and fish consumers. Recent studies in the Beaufort Sea have documented widespread terrestrial carbon use among invertebrates, but only limited use among nearshore fish consumers. Here, we examine the carbon source and diet of rapidly growing young-of-year Arctic cisco (Coregonus autumnalis) using stable isotope values (δ13C and δ15N) from muscle and diet analysis (stomach contents) during a critical and previously unsampled life stage. Stable isotope values (δ15N and δ13C) may differentiate between terrestrial and marine sources and integrate over longer time frames (weeks). Diet analysis provides species-specific information, but only from recent foraging (days). Average δ13C for all individuals was −25.7 ‰, with the smallest individuals possessing significantly depleted δ13C values indicative of a stronger reliance of terrestrial carbon sources as compared to larger individuals. Average δ15N for all individuals was 10.4 ‰, with little variation among individuals. As fish length increased, the proportion of offshore Calanus prey and neritic Mysis prey increased. Rapid young-of-year growth in Arctic cisco appears to use terrestrial carbon sources obtained by consuming a mixture of neritic and offshore zooplankton. Shifts in the magnitude or phenology of river discharge and the delivery of terrestrial carbon may alter the ecology of nearshore fish consumers.

On the anatomy of nearshore sandbars : A systematic exposition of inter-annual sandbar dynamics

NARCIS (Netherlands)

Walstra, D.J.R.

2016-01-01

Nearshore sandbars have a lifetime of many years, during which they exhibit cyclic, offshore directed behaviour with strong alongshore coherence. A bar is generated near the shoreline and grows in height and width while migrating offshore, before finally decaying at the seaward limit of the surf

Foraminiferal studies in nearshore regions of western coast of India and Laccadives Islands: A review

Digital Repository Service at National Institute of Oceanography (India)

Bhalla, S.N.; Khare, N.; Shanmukha, D.H.; Henriques, P.J.

The literature published on foraminiferal investigations carried out till date on nearshore, shallow water regions up to a depth of 50 m, along western coast of India, including Laccadive Archipelago has been reviewed. The aim is to prepare a...

Nearshore bars and the break-point hypothesis

Science.gov (United States)

Sallenger, A.H.; Howd, P.A.

1989-01-01

The set of hypotheses calling for bar formation at the break point was tested with field data. During two different experiments, waves were measured across the surf zone coincident with the development of a nearshore bar. We use a criterion, based on the wave height to depth ratio, to determine the offshore limit of the inner surf zone. During the first experiment, the bar became better developed and migrated offshore while remaining well within the inner surf zone. During the second experiment, the surf zone was narrower and we cannot rule out the possibility of break point processes contributing to bar development. We conclude that bars are not necessarily coupled with the break point and can become better developed and migrate offshore while being in the inner surf zone landward from initial wave breaking in the outer surf zone. ?? 1989.

Review of Nearshore Morphologic Prediction

Science.gov (United States)

Plant, N. G.; Dalyander, S.; Long, J.

2014-12-01

The evolution of the world's erodible coastlines will determine the balance between the benefits and costs associated with human and ecological utilization of shores, beaches, dunes, barrier islands, wetlands, and estuaries. So, we would like to predict coastal evolution to guide management and planning of human and ecological response to coastal changes. After decades of research investment in data collection, theoretical and statistical analysis, and model development we have a number of empirical, statistical, and deterministic models that can predict the evolution of the shoreline, beaches, dunes, and wetlands over time scales of hours to decades, and even predict the evolution of geologic strata over the course of millennia. Comparisons of predictions to data have demonstrated that these models can have meaningful predictive skill. But these comparisons also highlight the deficiencies in fundamental understanding, formulations, or data that are responsible for prediction errors and uncertainty. Here, we review a subset of predictive models of the nearshore to illustrate tradeoffs in complexity, predictive skill, and sensitivity to input data and parameterization errors. We identify where future improvement in prediction skill will result from improved theoretical understanding, and data collection, and model-data assimilation.

Molecular typing of Escherichia coli strains associated with threatened sea ducks and near-shore marine habitats of south-west Alaska

Science.gov (United States)

Hollmén, Tuula E.; DebRoy, Chitrita; Flint, Paul L.; Safine, David E.; Schamber, Jason L.; Riddle, Ann E.; Trust, Kimberly A.

2011-01-01

In Alaska, sea ducks winter in coastal habitats at remote, non-industrialized areas, as well as in proximity to human communities and industrial activity. We evaluated prevalence and characteristics of Escherichia coli strains in faecal samples of Steller's eiders (Polysticta stelleri; n = 122) and harlequin ducks (Histrionicus histrionicus; n = 21) at an industrialized site and Steller's eiders (n = 48) at a reference site, and compared these strains with those isolated from water samples from near-shore habitats of ducks. The overall prevalence of E. coli was 16% and 67% in Steller's eiders and harlequin ducks, respectively, at the industrialized study site, and 2% in Steller's eiders at the reference site. Based on O and H antigen subtyping and genetic characterization by enterobacterial repetitive intergenic consensus polymerase chain reaction and pulsed-field gel electrophoresis, we found evidence of avian pathogenic E. coli (APEC) strains associated with both species and detected E. coli strains carrying virulence genes associated with mammals in harlequin ducks. Steller's eiders that carried APEC had lower serum total protein and albumin concentrations, providing further evidence of pathogenicity. The genetic profile of two E. coli strains from water matched an isolate from a Steller's eider providing evidence of transmission between near-shore habitats and birds.

Molecular typing of Escherichia coli strains associated with threatened sea ducks and near-shore marine habitats of south-west Alaska.

Science.gov (United States)

Hollmén, Tuula E; Debroy, Chitrita; Flint, Paul L; Safine, David E; Schamber, Jason L; Riddle, Ann E; Trust, Kimberly A

2011-04-01

In Alaska, sea ducks winter in coastal habitats at remote, non-industrialized areas, as well as in proximity to human communities and industrial activity. We evaluated prevalence and characteristics of Escherichia coli strains in faecal samples of Steller's eiders (Polysticta stelleri; n = 122) and harlequin ducks (Histrionicus histrionicus; n = 21) at an industrialized site and Steller's eiders (n = 48) at a reference site, and compared these strains with those isolated from water samples from near-shore habitats of ducks. The overall prevalence of E. coli was 16% and 67% in Steller's eiders and harlequin ducks, respectively, at the industrialized study site, and 2% in Steller's eiders at the reference site. Based on O and H antigen subtyping and genetic characterization by enterobacterial repetitive intergenic consensus polymerase chain reaction and pulsed-field gel electrophoresis, we found evidence of avian pathogenic E. coli (APEC) strains associated with both species and detected E. coli strains carrying virulence genes associated with mammals in harlequin ducks. Steller's eiders that carried APEC had lower serum total protein and albumin concentrations, providing further evidence of pathogenicity. The genetic profile of two E. coli strains from water matched an isolate from a Steller's eider providing evidence of transmission between near-shore habitats and birds. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Blinded by the light? Nearshore energy pathway coupling and relative predator biomass increase with reduced water transparency across lakes.

Science.gov (United States)

Tunney, Tyler D; McCann, Kevin S; Jarvis, Lauren; Lester, Nigel P; Shuter, Brian J

2018-04-01

Habitat coupling is a concept that refers to consumer integration of resources derived from different habitats. This coupling unites fundamental food web pathways (e.g., cross-habitat trophic linkages) that mediate key ecological processes such as biomass flows, nutrient cycling, and stability. We consider the influence of water transparency, an important environmental driver in aquatic ecosystems, on habitat coupling by a light-sensitive predator, walleye (Sander vitreus), and its prey in 33 Canadian lakes. Our large-scale, across-lake study shows that the contribution of nearshore carbon (δ 13 C) relative to offshore carbon (δ 13 C) to walleye is higher in less transparent lakes. To a lesser degree, the contribution of nearshore carbon increased with a greater proportion of prey in nearshore compared to offshore habitats. Interestingly, water transparency and habitat coupling predict among-lake variation in walleye relative biomass. These findings support the idea that predator responses to changing conditions (e.g., water transparency) can fundamentally alter carbon pathways, and predator biomass, in aquatic ecosystems. Identifying environmental factors that influence habitat coupling is an important step toward understanding spatial food web structure in a changing world.

The European water framework directive: A challenge for nearshore, coastal and continental shelf research

Science.gov (United States)

Borja, Ángel

2005-09-01

The European Water Framework Directive (WFD) establishes a framework for the protection of groundwater, inland surface waters, estuarine waters, and coastal waters. The WFD constitutes a new view of the water resources management in Europe because, for the first time, water management is: (i) based mainly upon biological and ecological elements, with ecosystems being at the centre of the management decisions; (ii) applied to European water bodies, as a whole; and (iii) based upon the whole river basin, including also the adjacent coastal area. Although the marine water bodies affected by the WFD relate to only 19.8% of the whole of the European continental shelf, its application constitutes a challenge and an opportunity in nearshore, coastal and continental shelf research. This contribution highlights some of the main tasks and the research to be undertaken in the coming years, proposing investigations into: typologies; physico-chemical processes; indicator species; reference conditions; integration of the quality assessment; methodologies in determining ecological status, etc.

Nearshore waves and longshore sediment transport along Rameshwaram Island off the east coast of India

Directory of Open Access Journals (Sweden)

Rajamanickam Gowthaman

2015-11-01

Full Text Available Wave-induced Longshore Sediment Transport (LST play an important role in the dynamics of the Dhanushkodi sandspit located southeast of Rameshwaram. The LST along the Dhanushkodi coast is studied based on data collected simultaneously in Gulf of Mannar (GoM and Palk Bay (PB using directional waverider buoys. The numerical model REF/DIF1 was used to calculate the nearshore waves and the LST rate was estimated using three different formulae. The model validation was done based on the measured nearshore waves using InterOcean S4DW. Numerical model LITPACK was also used for simulating non-cohesive sediment transport and the LITLINE module was used to study the shoreline evolution over 5 years. Low net annual LST along PB (~0.01 × 106 m3 compared to the GoM region (0.3 × 106 m3 were due to the weak waves. Accretion in the region led to growth of the Dhanushkodi sandspit by 65 m during the period 2010-2015.

Natural fluctuations in nearshore turbidity and the relative influences of beach renourishment

OpenAIRE

Dompe, Philip E.

1993-01-01

Turbidity is a measure of the clarity of water. Turbidity depends upon the scattering and absorption of light by suspended particles. The focus of this study was to obtain quantitative measurements of turbidity in the nearshore zone, along with measurements of associated wave parameters and currents occurring naturally and during a beach nourishment project. The objectives were to make quantitative and qualitative comparisons between natural events and those induced by the dred...

Principal sources and dispersal patterns of suspended particulate matter in nearshore surface waters of the northeast Pacific Ocean and the Hawaiian Islands

Science.gov (United States)

Carlson, P. R. (Principal Investigator); Conomos, T. J.; Janda, R. J.; Peterson, D. H.

1973-01-01

The author has identified the following significant results. ERTS-1 multispectral scanner imagery of the nearshore surface waters of the Northeast Pacific Ocean is proving to be a useful tool for determining source and dispersal of suspended particulate matter. The principal sources of the turbid water, seen best on the green and red bands, are river and stream effluents and actively eroding coastlines; secondary sources are waste effluents and production of planktonic organisms, but these may sometimes be masked by the very turbid plumes of suspended sediment being discharged into the nearshore zone during times of high river discharge. The configuration and distribution of the plumes of turbid water also can be used to infer near-surface current directions. Comparison of imagery of the nearshore water off the northern California coast from October 1972 and January 1973 shows a reversal of the near-surface currents, from predominantly south-setting in the fall (California Current) to north-setting in the winter (Davidson Current).

Coastal Habitats in Puget Sound: A Research Plan in Support of the Puget Sound Nearshore Partnership

Science.gov (United States)

2006-11-01

2Puget Sound nearshore ecosystems encompass the bluffs, beaches, tide flats, estuaries, rocky shores, lagoons , salt marshes, and other shoreline features...investigations of intertidal benthic macroinvertebrate assemblages along Puget Sound and the Strait of Juan de Fuca (e.g., Long and others, 1983

Evidence of bottom-up limitations in nearshore marine systems based on otolith proxies of fish growth

Science.gov (United States)

von Biela, Vanessa R.; Kruse, Gordon H.; Mueter, Franz J.; Black, Bryan A.; Douglas, David C.; Helser, Thomas E.; Zimmerman, Christian E.

2015-01-01

Fish otolith growth increments were used as indices of annual production at nine nearshore sites within the Alaska Coastal Current (downwelling region) and California Current (upwelling region) systems (~36–60°N). Black rockfish (Sebastes melanops) and kelp greenling (Hexagrammos decagrammus) were identified as useful indicators in pelagic and benthic nearshore food webs, respectively. To examine the support for bottom-up limitations, common oceanographic indices of production [sea surface temperature (SST), upwelling, and chlorophyll-a concentration] during summer (April–September) were compared to spatial and temporal differences in fish growth using linear mixed models. The relationship between pelagic black rockfish growth and SST was positive in the cooler Alaska Coastal Current and negative in the warmer California Current. These contrasting growth responses to SST among current systems are consistent with the optimal stability window hypothesis in which pelagic production is maximized at intermediate levels of water column stability. Increased growth rates of black rockfish were associated with higher chlorophyll concentrations in the California Current only, but black rockfish growth was unrelated to the upwelling index in either current system. Benthic kelp greenling growth rates were positively associated with warmer temperatures and relaxation of downwelling (upwelling index near zero) in the Alaska Coastal Current, while none of the oceanographic indices were related to their growth in the California Current. Overall, our results are consistent with bottom-up forcing of nearshore marine ecosystems—light and nutrients constrain primary production in pelagic food webs, and temperature constrains benthic food webs.

A comparison of the marine and estuarine benthic fauna of the nearshore regions of the Arabian Sea.

Digital Repository Service at National Institute of Oceanography (India)

Desai, B.N.; Kutty, M.K.

The distribution and abundance of the benthic fauna of the Arabian sea were studied in the nearshore region at a depth of 10 fathoms, about 7 miles off Cochin. The results showed that the macrofauna was more abundant than the meiofauna...

The biological assessment of flora and fauna as standards for changes in the near-shore ocean environment: a study of Barbers Point Harbor.

Science.gov (United States)

Hokama, Y; Wachi, K M; Shiraki, A; Goo, C; Ebesu, J S

2001-02-01

The biological assessments of the flora and fauna in the near-shore ocean environment, specifically Barbers Point Harbor (BPH), demonstrate the usefulness of these biological analyses for evaluation of the changes occurring following man-made excavation for expansion of the harbor. The study included identification and enumeration of macroalgae and dinoflagellates and analyses of herbivores and carnivores in four areas within the perimeter of the harbor and the north and south entrances into the harbor. Numbers of macroalgae varied between 1994 and 1999 surveys, with significant decrease in numbers in stations C, D and E. Stations A and B were similar between 1994 and 1999 with a slight increase in 1999. The significant differences were shown with the appearance of Gambierdiscus toxicus (G toxicus) in 1999 among the algae in stations A and B. Assessment of herbivores and carnivores with the immunological membrane immunobead assay using monoclonal antibody to ciguatoxin and related polyethers demonstrated an increase in fish toxicity among the herbivore from 1994-1999 (22% increase) with a decrease (22%) in non-toxic fish. This was also demonstrated in the carnivores, but to a lesser degree. It is suggested that the biological analyses of the flora and the fauna of the near-shore ocean environment are appropriate to assess the changes that occur from natural and man-made alterations.

Thermography of the New River Inlet plume and nearshore currents

Science.gov (United States)

Chickadel, C.; Jessup, A.

2012-12-01

As part of the DARLA and RIVET experiments, thermal imaging systems mounted on a tower and in an airplane captured water flow in the New River Inlet, NC, USA. Kilometer-scale, airborne thermal imagery of the inlet details the ebb flow of the estuarine plume water mixing with ocean water. Multiple fronts, corresponding to the preferred channels through the ebb tidal delta, are imaged in the aerial data. A series of internal fronts suggest discreet sources of the tidal plume that vary with time. Focused thermal measurements made from a tower on the south side of the inlet viewed an area within a radius of a few hundred meters. Sub-meter resolution video from the tower revealed fine-scale flow features and the interaction of tidal exchange and wave-forced surfzone currents. Using the tower and airborne thermal image data we plan to provide geophysical information to compare with numerical models and in situ measurements made by other investigators. From the overflights, we will map the spatial and temporal extent of the estuarine plume to correlate with tidal phase and local wind conditions. From the tower data, we will investigate the structure of the nearshore flow using a thermal particle image velocimetry (PIV) technique, which is based on tracking motion of the surface temperature patterns. Long term variability of the mean and turbulent two-dimensional PIV currents will be correlated to local wave, tidal, and wind forcing parameters.

An Ephemeral Dinoflagellate Bloom during Summer Season in Nearshore Water of Puri, East Coast of India

Science.gov (United States)

Baliarsingh, Sanjiba Kumar; Dwivedi, Rashmin; Lotliker, Aneesh A.; Jayashankar, Reeta; Sahu, Biraja Kumar; Srichandan, Suchismita; Samanta, Alakes; Parida, Chandanlal; Srinivasakumar, Tummala; Sahu, Kali Charan

2018-03-01

The present paper reports on the phenomenon of pinkish-red discoloration of the nearshore water of Puri, Odisha on 12th May 2016. Many local newspapers covered this event, as Puri city is a major tourist and pilgrimage place on the east coast of India. Field observations were carried out in order to provide a scientific basis to the event and to elicit possible causes of this discoloration. Taxonomic analysis of the phytoplankton samples revealed the dominance of red colored dinoflagellate species Gonyaulax polygramma, contributing 90% to total phytoplankton population. The localized concentration of G. polygramma was responsible for the pinkish-red discoloration of nearshore water. The exact factor that lay behind the genesis of this bloom could not be delineated due to the short period of its persistence. But two factors - upwelling and anthropogenic nutrient influx - can be viewed as the main cause for this ephemeral bloom. Non-hypoxic conditions in the coastal water following the ephemeral bloom event indicated no significant risk of ecological deterioration to the ambient medium.

Dynamics of oxygen depletion in the nearshore of a coastal embayment of the southern Benguela upwelling system

CSIR Research Space (South Africa)

Pitcher, GC

2014-04-01

Full Text Available is characterized by seasonally recurrent hypoxia (<1.42 ml l(sup-1)) associated with a deep pool of oxygen-depleted water and episodic anoxia (<0.02 ml l(sup-1)) driven by the nearshore (<20 m isobath) decay of red tide. Coastal wind forcing influences DO...

Organic Carbon Loading in Tropical Near-Shore Ecosystems: the Role of Mangrove Lagoons and Channels in Coastal Ocean Acidification

Science.gov (United States)

García, E.; Morell, J. M.

2016-02-01

Low energy tropical Caribbean shores are often dominated by highly productive mangrove ecosystems that thrive on land borne inorganic nutrient inputs and whose net production results in significant export of litter and dissolved organic compounds (DOC). These organic matrixes can be effectively transported to nearby ecosystems, including coral reefs whose vulnerability to excessive organic loading has been widely documented. This study documents the seaward transport and transformation of organic carbon from mangrove bays, trough near-shore reef ecosystems and out to open waters in the La Parguera Marine Reserve (LPMR). Considering in-situ colored dissolved organic matter (CDOM) as a tracer for DOC, absorption coefficient values (a350) were observed in the 6.13-0.02 m-1 and 14.08-0.06 m-1 during the dry (from 0 to 0.18 inches of rain) and wet seasons (from 0.68 to 4.76 inches of rain), respectively. Spectral properties (S275-295 and SR) calculations indicate that DOC is predominantly of terrestrial origin and found in high concentrations in enclosed mangrove bays and canals. Data evidences a strong gradient in CDOM concentration decreasing t from inshore to outer shelf waters. Rain precipitation correlated well with high CDOM values (aλ values doubled) and forced LPMR to behave similarly to a river influenced estuary as shown when CDOM is correlated with salinity, contrary to its predominant negative estuary profile. When correlating CDOM with pH and dissolved oxygen concentrations, it is evident that high organic matter content is driving ocean acidification in the nearshore areas. The non-conservative behavior of CDOM implies that other processes besides dilution may play a significant role in its spatial distribution.

Evaluating the potential for near-shore bathymetry on the Majuro Atoll, Republic of the Marshall Islands, using Landsat 8 and WorldView-3 imagery

Science.gov (United States)

Poppenga, Sandra K.; Palaseanu-Lovejoy, Monica; Gesch, Dean B.; Danielson, Jeffrey J.; Tyler, Dean J.

2018-04-16

Satellite-derived near-shore bathymetry (SDB) is becoming an increasingly important method for assessing vulnerability to climate change and natural hazards in low-lying atolls of the northern tropical Pacific Ocean. Satellite imagery has become a cost-effective means for mapping near-shore bathymetry because ships cannot collect soundings safely while operating close to the shore. Also, green laser light detection and ranging (lidar) acquisitions are expensive in remote locations. Previous research has demonstrated that spectral band ratio-based techniques, commonly called the natural logarithm approach, may lead to more precise measurements and modeling of bathymetry because of the phenomenon that different substrates at the same depth have approximately equal ratio values. The goal of this research was to apply the band ratio technique to Landsat 8 at-sensor radiance imagery and WorldView-3 atmospherically corrected imagery in the coastal waters surrounding the Majuro Atoll, Republic of the Marshall Islands, to derive near-shore bathymetry that could be incorporated into a seamless topobathymetric digital elevation model of Majuro. Attenuation of light within the water column was characterized by measuring at-sensor radiance and reflectance at different depths and calculating an attenuation coefficient. Bathymetric lidar data, collected by the U.S. Naval Oceanographic Office in 2006, were used to calibrate the SDB results. The bathymetric lidar yielded a strong linear relation with water depths. The Landsat 8-derived SDB estimates derived from the blue/green band ratio exhibited a water attenuation extinction depth of 6 meters with a coefficient of determination R2=0.9324. Estimates derived from the coastal/red band ratio had an R2=0.9597. At the same extinction depth, SDB estimates derived from WorldView-3 imagery exhibited an R2=0.9574. Because highly dynamic coastal shorelines can be affected by erosion, wetland loss, hurricanes, sea-level rise, urban

Post-eruptive sediment transport and surface processes on unvegetated volcanic hillslopes - A case study of Black Tank scoria cone, Cima Volcanic Field, California

Science.gov (United States)

Kereszturi, Gábor; Németh, Károly

2016-08-01

Conical volcanic edifices that are made up from lapilli to block/bomb pyroclastic successions, such as scoria cones, are widespread in terrestrial and extraterrestrial settings. Eruptive processes responsible for establishing the final facies architecture of a scoria cone are not well linked to numerical simulations of their post-eruptive sediment transport. Using sedimentological, geomorphic and 2D fragment morphology data from a 15-ky-old scoria cone from the Cima Volcanic Field, California, this study provides field evidence of the various post-eruptive sediment transport and degradation processes of scoria cones located in arid to semi-arid environments. This study has revealed that pyroclast morphologies vary downslope due to syn-eruptive granular flows, along with post-eruptive modification by rolling, bouncing and sliding of individual particles down a slope, and overland flow processes. The variability of sediment transport rates on hillslopes are not directly controlled by local slope angle variability and the flank length but rather by grain size, and morphological characteristics of particles, such as shape irregularity of pyroclast fragments and block/lapilli ratio. Due to the abundance of hillslopes degrading in unvegetated regions, such as those found in the Southwestern USA, granulometric influences should be accounted for in the formulation of sediment transport laws for geomorphic modification of volcanic terrains over long geologic time.

Carolinas Coastal Change Processes Project data report for nearshore observations at Cape Hatteras, North Carolina

Science.gov (United States)

Armstrong, Brandy N.; Warner, John C.; Voulgaris, George; List, Jeffrey H.; Thieler, Robert; Martini, Marinna A.; Montgomery, Ellyn T.; McNinch, Jesse E.; Book, Jeffrey W.; Haas, Kevin

2013-01-01

An oceanographic field study conducted in February 2010 investigated processes that control nearshore flow and sediment transport dynamics at Cape Hatteras, North Carolina. This report describes the project background, field program, instrumentation setup, and locations of the sensor deployments. The data collected, and supporting meteorological and streamflow observations, are presented as time-series plots for data visualization. Additionally, the data are available as part of this report.

Nearshore dynamics of artificial sand and oil agglomerates

Science.gov (United States)

Dalyander, P. Soupy; Plant, Nathaniel G.; Long, Joseph W.; McLaughlin, Molly R.

2015-01-01

Weathered oil can mix with sediment to form heavier-than-water sand and oil agglomerates (SOAs) that can cause beach re-oiling for years after a spill. Few studies have focused on the physical dynamics of SOAs. In this study, artificial SOAs (aSOAs) were created and deployed in the nearshore, and shear stress-based mobility formulations were assessed to predict SOA response. Prediction sensitivity to uncertainty in hydrodynamic conditions and shear stress parameterizations were explored. Critical stress estimates accounting for large particle exposure in a mixed bed gave the best predictions of mobility under shoaling and breaking waves. In the surf zone, the 10-cm aSOA was immobile and began to bury in the seafloor while smaller size classes dispersed alongshore. aSOAs up to 5 cm in diameter were frequently mobilized in the swash zone. The uncertainty in predicting aSOA dynamics reflects a broader uncertainty in applying mobility and transport formulations to cm-sized particles.

Studies on impact of release of liquid industrial waste from soda ash industry in the nearshore water of north Gujarat

Digital Repository Service at National Institute of Oceanography (India)

Zingde, M.D.

The nearshore waters of Mithapur, Porbandar and Sutrapada received 18-100 mid (million litres per day) of wastewater from soda ash manufacturing industries either through point discharges (Mithapur, Porbandar) or through submarine outfall (Sutrapada...

Evaluating Carbonate System Algorithms in a Nearshore System: Does Total Alkalinity Matter?

Science.gov (United States)

Jones, Jonathan M; Sweet, Julia; Brzezinski, Mark A; McNair, Heather M; Passow, Uta

2016-01-01

Ocean acidification is a threat to many marine organisms, especially those that use calcium carbonate to form their shells and skeletons. The ability to accurately measure the carbonate system is the first step in characterizing the drivers behind this threat. Due to logistical realities, regular carbonate system sampling is not possible in many nearshore ocean habitats, particularly in remote, difficult-to-access locations. The ability to autonomously measure the carbonate system in situ relieves many of the logistical challenges; however, it is not always possible to measure the two required carbonate parameters autonomously. Observed relationships between sea surface salinity and total alkalinity can frequently provide a second carbonate parameter thus allowing for the calculation of the entire carbonate system. Here, we assessed the rigor of estimating total alkalinity from salinity at a depth sampling water from a pier in southern California for several carbonate system parameters. Carbonate system parameters based on measured values were compared with those based on estimated TA values. Total alkalinity was not predictable from salinity or from a combination of salinity and temperature at this site. However, dissolved inorganic carbon and the calcium carbonate saturation state of these nearshore surface waters could both be estimated within on average 5% of measured values using measured pH and salinity-derived or regionally averaged total alkalinity. Thus we find that the autonomous measurement of pH and salinity can be used to monitor trends in coastal changes in DIC and saturation state and be a useful method for high-frequency, long-term monitoring of ocean acidification.

Nearshore circulation revealed by wastewater discharge from a submarine outfall, Aveiro Coast, Portugal

Directory of Open Access Journals (Sweden)

J. Figueiredo da Silva

2002-01-01

Full Text Available The morphological and climatic conditions of the Atlantic coast of northern Portugal result in a prevailing upwelling circulation over the continental shelf. A submarine outfall releases wastewater into the ocean c. 3 km directly offshore (at ∼16 m water depth from S. Jacinto, 5 km to the north of the inlet to the estuarine coastal lagoon system of the Ria de Aveiro. The buoyant plume has a distinctive reddish brown colour and is clearly visible at the water surface. The transport and dispersion of the plume was monitored by airborne photography and by in situ water sampling. Results revealed the surface currents present and water mass fronts in the nearshore zone of the Aveiro coast. During the spring and summer, the plume was not transported offshore in the manner expected by the upwelling shelf circulation. Instead, it was commonly observed to be transported alongshore with the prevailing southerly circulation or with an onshore component. The transport to the south caused the outfall plume to interact with the circulation associated with the tidal currents generated in the inlet channel to the Ria de Aveiro. The observations suggest that the trophic status of the Ria de Aveiro is unlikely to change because of the operation of the submarine outfall. Furthermore, this study demonstrates how simple observations of wastewater discharge from a submarine outfall can be used to improve understanding of nearshore circulation. Keywords: water circulation, upwelling, ocean outfall, remote sensing, eutrophication, Ria de Aveiro

Nearshore Coastal Dynamics on a Sea-Breeze Dominated Micro-Tidal Beach (NCSAL)

Science.gov (United States)

Torres-Freyermuth, A.; Puleo, J. A.; Ruiz de Alegría-Arzaburu, A.; Figlus, J.; Mendoza, T.; Pintado-Patino, J. C.; Pieterse, A.; Chardon-Maldonado, P.; DiCosmo, N. R.; Wellman, N.; Garcia-Nava, H.; Palemón-Arcos, L.; Roberts, T.; López-González, J.; Bravo, M.; Ojeda, E.; Medellín, G.; Appendini, C. M.; Figueroa, B.; González-Leija, M.; Enriquez, C.; Pedrozo-Acuña, A.; Salles, P.

2014-12-01

A comprehensive field experiment devoted to the study of coastal processes on a micro-tidal beach was conducted from March 30th to April 12th 2014 in Sisal, Yucatán México. Wave conditions in the study area are controlled by local (i.e., sea-breezes) and meso-scale (i.e., Nortes) meteorological events. Simultaneous measurements of waves, tides, winds, currents, sediment transport, runup, and beach morphology were obtained in this experiment. Very dense nearshore instrumentation arrays allow us the study of the cross-/along- shore variability of surf/swash zone dynamics during different forcing conditions. Strong sea-breeze wind events produced a diurnal cycle with a maximum wind speed of 14 m/s. The persistent sea-breeze system forces small-amplitude (Hs1 m) Norte event, lasting 48 hours, reached the coast on April 8th generating a long-period swell (Tp>10 s) arriving from the NNW. This event induced an eastward net sediment transport across a wide surf zone. However, long-term observations of sand impoundment at a groin located near the study area suggests that the net sediment transport in the northern Yucatan peninsula is controlled by sea-breeze events and hence swash zone dynamics play an important role in the net sediment budget of this region. A comparative study of surf and swash zone dynamics during both sea-breeze and Norte events will be presented. The Institute of Engineering of UNAM, throughout an International Collaborative Project with the University of Delaware, and CONACYT (CB-167692) provided financial support. The first author acknowledges ONR Global for providing financial support throughout the Visiting Scientist Program.

Inferred fish behavior its implications for hydroacoustic surveys in nearshore habitats

Science.gov (United States)

DuFour, Mark R.; Mayer, Christine M.; Qian, Song S.; Vandergoot, Christopher; Kraus, Richard T.; Kocovsky, Patrick; Warner, David M.

2018-01-01

Population availability and vessel avoidance effects on hydroacoustic abundance estimates may be scale dependent; therefore, it is important to evaluate these biases across systems. We performed an inter-ship comparison survey to determine the effect of vessel size, day-night period, depth, and environmental gradients on walleye (Sander vitreus) density estimates in Lake Erie, an intermediate-scaled system. Consistent near-bottom depth distributions coupled with horizontal fish movements relative to vessel paths indicated avoidance behavior contributed to higher walleye densities from smaller vessels in shallow water (i.e., abundance estimates. Quantifying availability and avoidance behavior effects and partitioning sources of variation provides informed flexibility for designing future hydroacoustic surveys in shallow-water nearshore environments.

Analysis of the impacts of Wave Energy Converter arrays on the nearshore wave climate in the Pacific Northwest

Science.gov (United States)

O'Dea, A.; Haller, M. C.

2013-12-01

As concerns over the use of fossil fuels increase, more and more effort is being put into the search for renewable and reliable sources of energy. Developments in ocean technologies have made the extraction of wave energy a promising alternative. Commercial exploitation of wave energy would require the deployment of arrays of Wave Energy Converters (WECs) that include several to hundreds of individual devices. Interactions between WECs and ocean waves result in both near-field and far-field changes in the incident wave field, including a significant decrease in wave height and a redirection of waves in the lee of the array, referred to as the wave shadow. Nearshore wave height and direction are directly related to the wave radiation stresses that drive longshore currents, rip currents and nearshore sediment transport, which suggests that significant far-field changes in the wave field due to WEC arrays could have an impact on littoral processes. The goal of this study is to investigate the changes in nearshore wave conditions and radiation stress forcing as a result of an offshore array of point-absorber type WECs using a nested SWAN model, and to determine how array size, configuration, spacing and distance from shore influence these changes. The two sites of interest are the Northwest National Marine Renewable Energy Center (NNMREC) test sites off the coast of Newport Oregon, the North Energy Test Site (NETS) and the South Energy Test Site (SETS). NETS and SETS are permitted wave energy test sites located approximately 4 km and 10 km offshore, respectively. Twenty array configurations are simulated, including 5, 10, 25, 50 and 100 devices in two and three staggered rows in both closely spaced (three times the WEC diameter) and widely spaced (ten times the WEC diameter) arrays. Daily offshore wave spectra are obtained from a regional WAVEWATCH III hindcast for 2011, which are then propagated across the continental shelf using SWAN. Arrays are represented in SWAN

Baseline studies North Sea wind farms: Lot 5 marine birds in and around the future site Nearshore Windfarm (NSW)

NARCIS (Netherlands)

Leopold, M.F.; Camphuysen, C.J.; Lieshout, S.M.J.; Braak, ter C.J.F.; Dijkman, E.M.

2004-01-01

Dit rapport beschrijft de zeevogelgemeenschap die zich in de loop van het jaar bevindt in een zeegebied voor de Noord-Hollandse kust, waar in de nabije toekomst een experimenteel windmolenpark gebouwd zal worden, de zogenaamde Nearshore Windfarm (NSW). Om deze `T-nul` situatie te kunnen vastleggen

Predicting Output Power for Nearshore Wave Energy Harvesting

Directory of Open Access Journals (Sweden)

Henock Mamo Deberneh

2018-04-01

Full Text Available Energy harvested from a Wave Energy Converter (WEC varies greatly with the location of its installation. Determining an optimal location that can result in maximum output power is therefore critical. In this paper, we present a novel approach to predicting the output power of a nearshore WEC by characterizing ocean waves using floating buoys. We monitored the movement of the buoys using an Arduino-based data collection module, including a gyro-accelerometer sensor and a wireless transceiver. The collected data were utilized to train and test prediction models. The models were developed using machine learning algorithms: SVM, RF and ANN. The results of the experiments showed that measurements from the data collection module can yield a reliable predictor of output power. Furthermore, we found that the predictors work better when the regressors are combined with a classifier. The accuracy of the proposed prediction model suggests that it could be extremely useful in both locating optimal placement for wave energy harvesting plants and designing the shape of the buoys used by them.

Advances in Shallow-Water, High-Resolution Seafloor Mapping: Integrating an Autonomous Surface Vessel (ASV) Into Nearshore Geophysical Studies

Science.gov (United States)

Denny, J. F.; O'Brien, T. F.; Bergeron, E.; Twichell, D.; Worley, C. R.; Danforth, W. W.; Andrews, B. A.; Irwin, B.

2006-12-01

The U.S. Geological Survey (USGS) has been heavily involved in geological mapping of the seafloor since the 1970s. Early mapping efforts such as GLORIA provided broad-scale imagery of deep waters (depths > 400 meters) within the Exclusive Economic Zone (EEZ). In the early 1990's, the USGS research emphasis shifted from deep- to shallow-water environments (inner continental shelf, nearshore, estuaries) to address pertinent coastal issues such as erosion, sediment availability, sediment transport, vulnerability of coastal areas to natural and anthropogenic hazards, and resource management. Geologic framework mapping in these shallow- water environments has provided valuable data used to 1) define modern sediment distribution and thickness, 2) determine underlying stratigraphic and structural controls on shoreline behavior, and 3) enable onshore-to- offshore geologic mapping within the coastal zone when coupled with subaerial techniques such as GPR and topographic LIDAR. Research in nearshore areas presents technological challenges due to the dynamics of the environment, high volume of data collected, and the geophysical limitations of operating in very shallow water. In 2004, the USGS, in collaboration with NOAA's Coastal Services Center, began a multi-year seafloor mapping effort to better define oyster habitats within Apalachicola Bay, Florida, a shallow water estuary along the northern Gulf of Mexico. The bay poses a technological challenge due to its shallow depths (turbidity that prohibits the use of bathymetric LIDAR. To address this extreme shallow water setting, the USGS incorporated an Autonomous Surface Vessel (ASV) into seafloor mapping operations, in June 2006. The ASV is configured with a chirp sub-bottom profiler (4 24 kHz), dual-frequency chirp sidescan-sonar (100/500 kHz), single-beam echosounder (235 kHz), and forward-looking digital camera, and will be used to delineate the distribution and thickness of surficial sediment, presence of oyster beds

Wave hindcast studies using SWAN nested in WAVEWATCH III - comparison with measured nearshore buoy data off Karwar, eastern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Amrutha, M.M.; SanilKumar, V.; Sandhya, K.G.; Nair, T.M.B; Rathod, J.L.

Waves in the nearshore waters (~15 m water-depth) of eastern Arabian Sea were simulated using SWAN nested in WAVEWATCH III (WW3) for the year 2014. The sensitivity of the numerical wave model WW3 towards different source term (ST) packages...

Circulation, mixing, and transport in nearshore Lake Erie in the vicinity of Villa Angela Beach and Euclid Creek, Cleveland, Ohio, September 11-12, 2012

Science.gov (United States)

Jackson, P. Ryan

2013-01-01

Villa Angela Beach, on the Lake Erie lakeshore near Cleveland, Ohio, is adjacent to the mouth of Euclid Creek, a small, flashy stream draining approximately 23 square miles and susceptible to periodic contamination from combined sewer overflows (CSOs) (97 and 163 CSO events in 2010 and 2011, respectively). Concerns over high concentrations of Escherichia coli (E. coli) in water samples taken along this beach and frequent beach closures led to the collection of synoptic data in the nearshore area in an attempt to gain insights into mixing processes, circulation, and the potential for transport of bacteria and other CSO-related pollutants from various sources in Euclid Creek and along the lakefront. An integrated synoptic survey was completed by the U.S. Geological Survey on September 11–12, 2012, during low-flow conditions on Euclid Creek, which followed rain-induced high flows in the creek on September 8–9, 2012. Data-collection methods included deployment of an autonomous underwater vehicle and use of a manned boat equipped with an acoustic Doppler current profiler. Spatial distributions of water-quality measures and nearshore currents indicated that the mixing zone encompassing the mouth of Euclid Creek and Villa Angela Beach is dynamic and highly variable in extent, but can exhibit a large zone of recirculation that can, at times, be decoupled from local wind forcing. Observed circulation patterns during September 2012 indicated that pollutants from CSOs in Euclid Creek and water discharged from three shoreline CSO points within 2,000 feet of the beach could be trapped along Villa Angela Beach by interaction of nearshore currents and shoreline structures. In spite of observed coastal downwelling, denser water from Euclid Creek is shown to mix to the surface via offshore turbulent structures that span the full depth of flow. While the southwesterly longshore currents driving the recirculation pattern along the beach front were observed during the 2011–12

Upwelling and Other Environmental Influences on Growth of a Nearshore Benthic Fish

Science.gov (United States)

von Biela, V. R.; Zimmerman, C. E.; Kruse, G. H.; Mueter, F. J.; Black, B.; Douglas, D. C.; Bodkin, J. L.

2016-02-01

The role of upwelling in nearshore benthic systems is more uncertain compared to the relatively strong positive associations with pelagic production. To understand how upwelling and other environmental conditions influence nearshore benthic production, we developed an annual index of production from growth increments recorded in otoliths of kelp greenling (Hexagrammos decagrammus) at nine sites in the seasonally-upwelling California Current and downwelling Alaska Coastal currents. Kelp greenling are a benthic-feeding fish common in kelp forests with food webs sustained by both kelp and phytoplankton primary production. We explored the influence of basin- and local-scale conditions, including upwelling, across all seasons at lags up to two years taken to represent changes in the quantity and quality of prey. Upwelling strength was positively related to fish growth in both current systems, although relationships in the Alaska Coastal Current were indicative of faster growth with relaxed downwelling, rather than upwelling. Looking across a suite of basin- and local-scale environmental indicators, complex relationships emerged in the California Current, with faster growth related to within-year warm conditions and lagged-year cool conditions. In contrast, fish in the downwelling system grew faster both during and subsequent to warm conditions. The complex lag-dependent dynamics in the upwelling system may reflect differences in conditions that promote quantity versus quality of benthic invertebrate prey. Thus, we hypothesize that benthic production is maximized when cool and warm years alternate during periods of high frequency climate variability in the California Current. Such a pattern is consistent with previous findings suggesting that benthic invertebrate abundance (e.g., recruitment) is food-limited during warm years with reduced upwelling, while quality (e.g., energy content) is temperature-limited during cool years.

Effects of oil and chemically treated oil on nearshore under-ice meiofauna studied in-situ

Energy Technology Data Exchange (ETDEWEB)

Cross, W.E.; Martin, C.M.

1987-01-01

Meiofauna were collected during May 1982 in the soft bottom layer of nearshore landfast ice at Cape Hatt, northern Baffin Island. Average abundance of all ice meiofauna was 54,000 individualsm/sup -2/. Densities of all meiofauna groups were spatially variable, but only nematodes and cyclopoid copepods showed evidence of progressive temporal change between 18 May and 2 June. Undisturbed, enclosed areas of the under-ice surface were treated with oil on 23-24 May. Dispersed oil was in contact with the ice for 5 hours, whereas untreated oil and solidified oil remained in the enclosures for the duration of the study (12 days post-treatment). Sampling was carried out in areas where oil contacted the ice and moved away or in areas near oil that remained in contact with the under-ice surface. Five hours after treatment, oil concentrations in the water within the enclosures were similar (0.15-0.28 ppm) in untreated oil, solidified oil and control enclosures. In contrast, dispersed oil concentrations were 5.8-36.5 ppm. Densities of all copepods and polychaetes decreased dramatically in each dispersed oil enclosure by the second post-spill day, and slight density increases were evident by the tenth post-spill day. Harpacticoid copepods apparently were more sensitive to dispersed oil than were cyclopoid copepods. Densities of nematodes and cyclopoid copepod nauplii were not affected by dispersed oil. Densities of nematodes, polychaetes and all copepods were not affected by untreated or solidified oil, but there was some evidence of a stimulatory effect of those treatments on some copepod groups and life stages. 24 refs., 2 figs., 4 tabs.

Spectral signature selection for mapping unvegetated soils

Science.gov (United States)

May, G. A.; Petersen, G. W.

1975-01-01

Airborne multispectral scanner data covering the wavelength interval from 0.40-2.60 microns were collected at an altitude of 1000 m above the terrain in southeastern Pennsylvania. Uniform training areas were selected within three sites from this flightline. Soil samples were collected from each site and a procedure developed to allow assignment of scan line and element number from the multispectral scanner data to each sampling location. These soil samples were analyzed on a spectrophotometer and laboratory spectral signatures were derived. After correcting for solar radiation and atmospheric attenuation, the laboratory signatures were compared to the spectral signatures derived from these same soils using multispectral scanner data. Both signatures were used in supervised and unsupervised classification routines. Computer-generated maps using the laboratory and multispectral scanner derived signatures resulted in maps that were similar to maps resulting from field surveys. Approximately 90% agreement was obtained between classification maps produced using multispectral scanner derived signatures and laboratory derived signatures.

Temporal-spatial variations and influencing factors of nitrogen in the shallow groundwater of the nearshore vegetable field of Erhai Lake, China.

Science.gov (United States)

Chen, Anqiang; Lei, Baokun; Hu, Wanli; Wang, Hongyuan; Zhai, Limei; Mao, Yanting; Fu, Bin; Zhang, Dan

2018-02-01

Nitrogen export from the nearshore vegetable field of Erhai Lake seriously threatens the water quality of Erhai Lake, which is the second largest highland freshwater lake in Yunnan Province, China. Among the nitrogen flows into Erhai Lake, shallow groundwater migration is a major pathway. The nitrogen variation and influencing factors in the shallow groundwater of the nearshore vegetable field of Erhai Lake are not well documented. A 2-year field experiment was conducted to determine the concentrations of nitrogen species in the shallow groundwater and their influencing factors in the nearshore vegetable field of Erhai Lake. The results showed that concentrations of TN, NO 3 - -N, and NO 2 - -N gradually increased with increasing elevation and distance from Erhai Lake, but the opposite was observed for NH 4 + -N in the shallow groundwater. The concentrations of nitrogen species in the rainy season were greater than those in the dry season. NO 3 - -N accounted for more than 79% of total nitrogen in shallow groundwater. Redundancy analysis showed that more than 70% of the temporal and spatial variations of nitrogen concentrations in the shallow groundwater were explained by shallow groundwater depth, and only approximately 10% of variation was explained by the factors of soil porosity, silt clay content of soil, and NH 4 + -N and NO 3 - -N concentrations of soil (p shallow groundwater depth had more notable effects on nitrogen concentrations in the shallow groundwater than other factors. This result will strongly support the need for further research regarding the management practices for reducing nitrogen concentrations in shallow groundwater.

Benthic and fish population monitoring associated with a marine protected area in the nearshore waters of Grenada, Eastern Caribbean

Directory of Open Access Journals (Sweden)

Robert Anderson

2012-03-01

Full Text Available Annual benthic and fish population surveys were completed at five locations in the nearshore waters along Grenada´s southwest coast during 2008-2010. Two survey sites are located in a newly launched Marine Protected Area (MPA. Photo Quadrat (PQ and Point Line Intercept (PLI surveys were used to determine substrate cover. Algae was the primary live cover increasing significantly from 45.9% in 2008 to 52.7% in 2010 (PLI. Algae was also predominant (61.0%-59.3% in the PQ surveys although annual variation was not significant. Hard coral cover ranged from 16.5% to 15.4% (PLI and 11.4% to12.0% (PQ with no significant differences between years. Branching and encrusting corals occurred more frequently than massive corals. In the three annual surveys neither algal cover nor hard coral varied significantly between MPA and non-protected areas (PLI. Relative abundance of fishes along 30x2m belt transects did not vary significantly among years however density of fishes decreased significantly across years for most major groups. Chromis spp. dominated the survey sites at 65.2% in 2008 and 49.8% in 2010, followed by territorial damselfish,11.1% and 15.5%, wrasse increased from 7.3% to 15.5%. Both the substrate cover and fish survey data analyses indicated a stable but degraded community. Annual surveys are planned at these sites for the foreseeable future. Existing and future data from this project will be valuable in determining the efficacy of MPA management, guiding resource management decisions and monitoring the health status of Grenada’s valuable reef systemsUn estudio sobre poblaciones bentónicas y de peces fue realizado en cinco localidades en la zona costera en el suroeste de Grenada entre 2008 y 2010. Dos sitios se ubicaron en una Área Marina Portegida (AMP recientemente creada. Para determinar la cobertura se utilizaron foto-cuadrantes (FQ y transectos de intersección de puntos (TIP. Las algas fueron el principal componente del bentos

A study of fish and shellfish radioactivity levels in Cumbrian near-shore waters

International Nuclear Information System (INIS)

McKay, W.A.; Szweda, C.

1987-07-01

Fish (cod, plaice, whiting and skate), crustacea (shrimp, Nephrops, crab and lobster) and mollusc (winkle) samples were collected from Cumbrian near-shore waters between November 1984 and the end of December 1986. The samples were analysed for total beta activity and a range of gamma and alpha emitters. In general the radionuclide levels were lower in 1986 than in 1985. On the assumption of constant consumption rates, the intakes of all consumers have decreased. In particular, the doses incurred by the critical group of local seafood consumers near Sellafield, mainly due to winkle consumption, were below the ICRP dose limit for the public of 1 mSv year -1 . (author)

Multi-disciplinary investigation into the role of regional event beds in near-shore landslides

Science.gov (United States)

Vardy, M. E.; L'Heureux, J.; Vanneste, M. W.; Longva, O.; Forsberg, C. F.; Steiner, A.

2012-12-01

Near-shore landslides in fjords are a widely observed geohazard with a potential for causing damage through tsunami generation and the removal of near-shore infrastructure. Often these events cross the border between terrestrial and submarine landslides, involving the failure of material on the shoreline and foreshore slope. Here we focus on a multi-disciplinary investigation of the 1996 landslide near Finneidfjord, Norway. This event back-stepped 100-150 m inland, removing a 250 m long section of the main north-south highway and several houses, at a cost of four human lives. Acquisition of an extensive and multidisciplinary data set, including high-resolution swath bathymetry, 2D/3D seismic data, multiple short (up to 6 m) and two long (12 m and 14 m, respectively) sediment cores and in situ Free-Fall Piezocone Penetrometer (FF-CPTU) profiles complemented with geotechnical laboratory data, has provided a detailed analysis of both the landslide morphology and stratigraphic controls. Correlating the geophysical (include remote physical properties inverted from seismic reflection profiles), geological and geotechnical data identifies the landslide glide plane as a thin (< 0.5 m), laminated, clay-rich bed with high pore water content (45 - 65 %) and low shear strength (4 - 8 kPa), deposited as a result of terrestrial quick-clay landslides in the hinterland. The relative weakness of the layer is thought to be a result of both the rapid deposition and excess pore pressure caused by artesian groundwater flow. Together, these act as preconditioning factors for failure, controlling the failure depth and probability if not the exact timing of the event.

Geochemical behavior of 210Pb and 210Po in the nearshore waters off western Taiwan

International Nuclear Information System (INIS)

Wei, Ching-Ling; Lin, Shiao-Yu; Wen, Liang-Saw; Sheu, David D.-D.

2012-01-01

Highlights: ► 210 Pb and 210 Po in the nearshore waters were determined off western coast of Taiwan. ► Partitioning of the radionuclides in turbid waters was discussed. ► Removal flux of particulate organic carbon was quantified using 210 Po proxy. - Abstract: Dissolved and particulate 210 Pb and 210 Po were determined at 15 stations along the coastline off western Taiwan in April 2007. The 210 Pb activities in dissolved and particulate phases fell within a relatively small range of 2.4–5.2 dpm 100 L −1 and 1.0–3.2 dpm 100 L −1 , respectively. The dissolved and particulate 210 Po activities also fell within a small range of 0.8–3.4 dpm 100 L −1 and 1.1–2.9 dpm 100 L −1 , respectively. The correlation of the distribution coefficients (K d ) of 210 Pb and 210 Po with particle concentration in turbid waters are not as evident as in the open ocean. The mass balance calculation shows that the residence times of 210 Pb and 210 Po with respect to particle removal from the nearshore waters ranges from 3 to 15 days and from 14 to 125 days, respectively. The flux of particulate organic carbon was estimated by 210 Po proxy and ranged from 4.8 to 33.7 mmol-C m −2 d −1 .

Research objectives to support the South Florida Ecosystem Restoration initiative-Water Conservation Areas, Lake Okeechobee, and the East/West waterways

OpenAIRE

Kitchens, Wiley M.

1994-01-01

The South Florida Ecosystem encompasses an area of approximately 28,000 km2 comprising at least 11 major physiographic provinces, including the Kissimmee River Valley, Lake Okeechobee, the Immokalee Rise, the Big Cypress, the Everglades, Florida Bay, the Atlantic Coastal Ridge, Biscayne Bay, the Florida Keys, the Florida Reef Tract, and nearshore coastal waters. South Florida is a heterogeneous system of wetlands, uplands, coastal areas, and marine areas, dominated by the watershe...

Occurrence of Escherichia coli and Enterococci in Cladophora (Chlorophyta) in Nearshore Water and Beach Sand of Lake Michigan†

OpenAIRE

Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

2003-01-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation...

The impact of Cyclone Nargis on the Ayeyarwady (Irrawaddy) River delta shoreline and nearshore zone (Myanmar): Towards degraded delta resilience?

Science.gov (United States)

Besset, Manon; Anthony, Edward J.; Dussouillez, Philippe; Goichot, Marc

2017-10-01

The Ayeyarwady River delta (Myanmar) is exposed to tropical cyclones, of which the most devastating has been cyclone Nargis (2-4 May 2008). We analysed waves, flooded area, nearshore suspended sediments, and shoreline change from satellite images. Suspended sediment concentrations up to 40% above average during the cyclone may reflect fluvial mud supply following heavy rainfall and wave reworking of shoreface mud. Massive recession of the high-water line resulted from backshore flooding by cyclone surge. The shoreline showed a mean retreat of 47 m following Nargis. Erosion was stronger afterwards (-148 m between August 2008 and April 2010), largely exceeding rates prior to Nargis (2000-2005: -2.14 m/year) and over 41 years (1974-2015: -0.62 m/year). This implies that resilience was weak following cyclone impact. Consequently, the increasingly more populous Ayeyarwady delta, rendered more and more vulnerable by decreasing fluvial sediment supply, could, potentially, become more severely impacted by future high-energy events.

Hydrothermal influence on nearshore sediments of Kos Island, Aegean Sea

Science.gov (United States)

Megalovasilis, Pavlos; Godelitsas, Athanasios

2015-04-01

The Kos-Nisyros volcanic centre is a long-active, Plio-Pleistocene magmatic system in the subduction zone along the easternmost edge of the active Hellenic volcanic arc in the Aegean Sea. Although today there are signs of relative quiescence in volcanic activity, active onshore fumaroles and shallow-sea hydrothermal vents persist on, amongst others, the island of Kos. The present study explores the large-scale imprint of hydrothermally sourced heavy metals and nutrients on the island's coastal marine environment, based on geochemical data collected in September 2007 from hydrothermal waters and surficial nearshore sediments (Kos is severely influenced by ongoing submarine hydrothermal activity, and confirm that shallow-water sediment Fe, Mn, Zn and Pb levels are substantially higher than those of other islands along the Hellenic volcanic arc, and even exceed those of some deep-water hydrothermal vents in other world regions. Evidently, there may be significant metallic sulphide deposits of hydrothermal origin at depth beneath Kos.

Morphological deformities of benthic foraminifera in response to nearshore pollution of the Red Sea, Egypt.

Science.gov (United States)

El-Kahawy, R; El-Shafeiy, M; Helal, S A; Aboul-Ela, N; El-Wahab, M Abd

2018-04-28

The Red Sea encompasses a wide range of tropical marine habitats that are stressed due to anthropogenic activities. The main anthropogenic activities are hydrocarbon exploration and important trading harbors. This work aims to assess the influence of the Red Sea coastal heavy metal contamination on the marine meiofauna along three sites (Ras Gharib, Safaga, and Quseir). Eight heavy metal (Cu, Cd, Zn, Pb, Cr, Co, Ni, and Mn) contents are considered in four benthic foraminiferal species (Elphidium striatopunctatum, Amphistegina lobifera, Amphisorus hemprichii, and Ammonia beccarii). Quseir Harbor showed the highest level of pollution followed by Safaga and Ras Gharib sites. The analyzed benthic foraminiferal tests displayed noteworthy high concentrations of Cd, Zn, and Pb in Quseir Harbor which could be attributed to the anthropogenic activities in the nearshore areas. Some foraminiferal tests exhibited abnormalities in their apertures, coiling, and shape of chambers. A comparison between normal and deformed foraminiferal tests revealed that the deformed ones are highly contaminated with elevated heavy metal contents such as Fe, Mn, Ni, and Cd. Statistics in addition to geo-accumulation and pollution load indices reveal a whistling alarm for the Quseir harbor. The present data are necessary to improve conservation and management of the Red Sea ecosystem in the near future.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

OpenAIRE

Jacob Sharvit; Nizan Salomonski; Roger Alimi; Hovav Zafrir; Tsuriel Ram Cohen; Boris Ginzburg; Eyal Weiss

2007-01-01

The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of ...

Inland and Near-Shore Water Profiles Derived from the High-Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

Science.gov (United States)

Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

2016-01-01

The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532-nanometer laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in ice caps, sea ice, and vegetation, the polar-orbiting satellite will observe global surface water during its designed three-year life span, including inland waterbodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype, the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high-altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the data sets of three MABEL transects observed from 20 kilometers above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 kilometers in length and included the middle Chesapeake Bay, the near-shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision ofapproximately 5-7 centimeters per 100-meter segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR (sub 0), were observed over a range of 1.3 to 9.3 meters, depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when the solar background rate was low. Near-shore bottom reflectance was detected only at the Lake Mead site down to a maximum of 10 meters under a clear night sky and low turbidity of approximately 1

A 3D unstructured grid nearshore hydrodynamic model based on the vortex force formalism

Science.gov (United States)

Zheng, Peng; Li, Ming; van der A, Dominic A.; van der Zanden, Joep; Wolf, Judith; Chen, Xueen; Wang, Caixia

2017-08-01

A new three-dimensional nearshore hydrodynamic model system is developed based on the unstructured-grid version of the third generation spectral wave model SWAN (Un-SWAN) coupled with the three-dimensional ocean circulation model FVCOM to enable the full representation of the wave-current interaction in the nearshore region. A new wave-current coupling scheme is developed by adopting the vortex-force (VF) scheme to represent the wave-current interaction. The GLS turbulence model is also modified to better reproduce wave-breaking enhanced turbulence, together with a roller transport model to account for the effect of surface wave roller. This new model system is validated first against a theoretical case of obliquely incident waves on a planar beach, and then applied to three test cases: a laboratory scale experiment of normal waves on a beach with a fixed breaker bar, a field experiment of oblique incident waves on a natural, sandy barred beach (Duck'94 experiment), and a laboratory study of normal-incident waves propagating around a shore-parallel breakwater. Overall, the model predictions agree well with the available measurements in these tests, illustrating the robustness and efficiency of the present model for very different spatial scales and hydrodynamic conditions. Sensitivity tests indicate the importance of roller effects and wave energy dissipation on the mean flow (undertow) profile over the depth. These tests further suggest to adopt a spatially varying value for roller effects across the beach. In addition, the parameter values in the GLS turbulence model should be spatially inhomogeneous, which leads to better prediction of the turbulent kinetic energy and an improved prediction of the undertow velocity profile.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

OpenAIRE

Weiss, Eyal; Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

2007-01-01

The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km sout...

Survey of the state of the art in near-shore pipeline location and burial assessment

International Nuclear Information System (INIS)

Wilkey, P.L.

1991-11-01

Project's objective is to evaluate state-of-the-art methods for locating pipelines in shallow (less than 15 ft) water and for determining and monitoring their burial depths. The following recommendations are made on the research needed in three areas for locating near-shore, shallowly buried pipelines: (1) Sensors: The pipeline industry has selected the magnetic gradiometer array (GA) as a preferred sensor method. Other potential methods exist as backups. No additional research is recommended. (2) Remotely Operated Vehicles (ROVs): The Pipeline Research Committee is pursuing development of a prototype ROV is deliver the GA or other similar equipment to pipeline locations. (3) Phenomena: The data being collected from research on the phenomena affecting seabed conditions and the bathymetric data being collected along the Gulf Coast should be synthesized. This new effort should focus on identifying erosion-prone areas with respect to present and potential future pipeline locations. Technical approach is to get the broadest perspective on the concerns related to the determination of burial conditions for offshore pipelines, Argonne National Laboratory (ANL) contacted individuals and organizations from the gas and petroleum industries, hardware and software vendors, academicians, and representatives from the government. A literature survey yielded the names of persons within academia who are presently working on similar applications with sensors. In the oil and gas industry, individuals and organizations involved in the Pipeline Research Committee made extensive contributions to the review and also provided the names of meaningful contacts from among their vendors. Discussions were held with the various persons both on the telephone and face to face. Vendors provided background materials and overview presentations on their capabilities for ANL to review

Baseline studies North Sea wind farms: Lot 5 marine birds in and around the future sites Nearshore Windfarm (NSW) and Q7

NARCIS (Netherlands)

Leopold, M.F.; Camphuysen, C.J.; Braak, ter C.J.F.; Dijkman, E.M.; Kersting, K.; Lieshout, S.M.J.

2004-01-01

Dit rapport beschrijft de zeevogelgemeenschap die zich in de loop van het jaar bevindt in een zeegebied voor de Noord-Hollandse kust, waar in de nabije toekomst twee windmolenparken gebouwd zullen worden, de zogenaamde Nearshore Windfarm (NSW) en het windmolenpark Q7. Om deze ¿T-nul¿ situatie te

Comparing a quasi-3D to a full 3D nearshore circulation model: SHORECIRC and ROMS

Science.gov (United States)

Haas, Kevin A.; Warner, John C.

2009-01-01

Predictions of nearshore and surf zone processes are important for determining coastal circulation, impacts of storms, navigation, and recreational safety. Numerical modeling of these systems facilitates advancements in our understanding of coastal changes and can provide predictive capabilities for resource managers. There exists many nearshore coastal circulation models, however they are mostly limited or typically only applied as depth integrated models. SHORECIRC is an established surf zone circulation model that is quasi-3D to allow the effect of the variability in the vertical structure of the currents while maintaining the computational advantage of a 2DH model. Here we compare SHORECIRC to ROMS, a fully 3D ocean circulation model which now includes a three dimensional formulation for the wave-driven flows. We compare the models with three different test applications for: (i) spectral waves approaching a plane beach with an oblique angle of incidence; (ii) monochromatic waves driving longshore currents in a laboratory basin; and (iii) monochromatic waves on a barred beach with rip channels in a laboratory basin. Results identify that the models are very similar for the depth integrated flows and qualitatively consistent for the vertically varying components. The differences are primarily the result of the vertically varying radiation stress utilized by ROMS and the utilization of long wave theory for the radiation stress formulation in vertical varying momentum balance by SHORECIRC. The quasi-3D model is faster, however the applicability of the fully 3D model allows it to extend over a broader range of processes, temporal, and spatial scales.

Effects of nearshore evaporation rates on the design of seabed gallery intake systems for SWRO facilities located along the Red Sea shoreline of Saudi Arabia

KAUST Repository

Dehwah, Abdullah

2015-10-12

Feed water to seawater reverse osmosis desalination systems should have a constant salinity with minimal variation. Intake systems that extract water from shallow nearshore areas in arid regions can exhibit significant fluctuations in salinity caused by high rates of evaporation and lack of circulation. Such fluctuations in salinity could inhibit the design, construction, and operation of seabed gallery intake systems located in shallow nearshore areas, such as the Red Sea inner shelf. Water depths range from 0 to 2 m between the beach and the edge of the fringing reef in the optimal locations for the development of seabed gallery intakes along the coast of the Red Sea of Saudi Arabia. The evaporation rate in this area is between 2 and 3 m per year. The bottom consists of mostly a marine hardground containing a thin veneer of unlithified sediment and no significant cover of corals or seagrass. The rather barren nature of the bottom suggests that periodic hypersalinity may contribute to the formation of hardgrounds on the bottom by causing supersaturation of the seawater with calcium carbonate and may limit the growth of corals and grasses. To assess the changes in salinity, a conceptual model was developed which assumes that a shallow circulation cell develops between the shoreline and deeper water offshore. Lower salinity seawater should migrate landward to replace water loss caused by evaporation with seaward moving of high-salinity water occurring along the bottom to balance the flow with ultimate mixing before the reef tract. To test this circulation pattern, a series of sensors were deployed to continuously monitor the water temperature, conductivity, and salinity at the surface and at the bottom during several periods of high air temperature. Surprisingly, the results show very little variation in salinity, despite the very high evaporation loss. The water salinity ranged between 39,000 and 40,000 mg/L with no diurnal variations of significance. Based on the

A survey of fish and shellfish radioactivity levels in Cumbrian near-shore waters (1990)

Energy Technology Data Exchange (ETDEWEB)

McKay, W A; Memmott, S D

1991-09-01

Fish (cod and plaice), crustacea, (crab and lobster), and molluscs (winkle) samples were collected from Cumbrian near-shore waters in 1990. The samples were analysed for total beta activity and a range of gamma and alpha emitters. In general, the radionuclide levels are lower than those measured in the previous 3 years of the study and the intake of radioactivity by all consumers should have reflected this. The dose estimated to have been incurred by the critical group of local seafood consumers near Sellafield in 1990, mainly due to winkle consumption, is less than 0.1 mSv and thus significantly below the limit of 1 mSv per year for long term radiation exposure recommended by the International Commission on Radiological Protection. (author).

A survey of fish and shellfish radioactivity levels in Cumbrian near-shore waters (1990)

International Nuclear Information System (INIS)

McKay, W.A.; Memmott, S.D.

1991-09-01

Fish (cod and plaice), crustacea, (crab and lobster), and molluscs (winkle) samples were collected from Cumbrian near-shore waters in 1990. The samples were analysed for total beta activity and a range of gamma and alpha emitters. In general, the radionuclide levels are lower than those measured in the previous 3 years of the study and the intake of radioactivity by all consumers should have reflected this. The dose estimated to have been incurred by the critical group of local seafood consumers near Sellafield in 1990, mainly due to winkle consumption, is less than 0.1 mSv and thus significantly below the limit of 1 mSv per year for long term radiation exposure recommended by the International Commission on Radiological Protection. (author)

Predicting species diversity of benthic communities within turbid nearshore using full-waveform bathymetric LiDAR and machine learners.

Directory of Open Access Journals (Sweden)

Antoine Collin

Full Text Available Epi-macrobenthic species richness, abundance and composition are linked with type, assemblage and structural complexity of seabed habitat within coastal ecosystems. However, the evaluation of these habitats is highly hindered by limitations related to both waterborne surveys (slow acquisition, shallow water and low reactivity and water clarity (turbid for most coastal areas. Substratum type/diversity and bathymetric features were elucidated using a supervised method applied to airborne bathymetric LiDAR waveforms over Saint-Siméon-Bonaventure's nearshore area (Gulf of Saint-Lawrence, Québec, Canada. High-resolution underwater photographs were taken at three hundred stations across an 8-km(2 study area. Seven models based upon state-of-the-art machine learning techniques such as Naïve Bayes, Regression Tree, Classification Tree, C 4.5, Random Forest, Support Vector Machine, and CN2 learners were tested for predicting eight epi-macrobenthic species diversity metrics as a function of the class number. The Random Forest outperformed other models with a three-discretized Simpson index applied to epi-macrobenthic communities, explaining 69% (Classification Accuracy of its variability by mean bathymetry, time range and skewness derived from the LiDAR waveform. Corroborating marine ecological theory, areas with low Simpson epi-macrobenthic diversity responded to low water depths, high skewness and time range, whereas higher Simpson diversity relied upon deeper bottoms (correlated with stronger hydrodynamics and low skewness and time range. The degree of species heterogeneity was therefore positively linked with the degree of the structural complexity of the benthic cover. This work underpins that fully exploited bathymetric LiDAR (not only bathymetrically derived by-products, coupled with proficient machine learner, is able to rapidly predict habitat characteristics at a spatial resolution relevant to epi-macrobenthos diversity, ranging from clear to

Parameterization of Time-Averaged Suspended Sediment Concentration in the Nearshore

Directory of Open Access Journals (Sweden)

Hyun-Doug Yoon

2015-11-01

Full Text Available To quantify the effect of wave breaking turbulence on sediment transport in the nearshore, the vertical distribution of time-averaged suspended sediment concentration (SSC in the surf zone was parameterized in terms of the turbulent kinetic energy (TKE at different cross-shore locations, including the bar crest, bar trough, and inner surf zone. Using data from a large-scale laboratory experiment, a simple relationship was developed between the time-averaged SSC and the time-averaged TKE. The vertical variation of the time-averaged SSC was fitted to an equation analogous to the turbulent dissipation rate term. At the bar crest, the proposed equation was slightly modified to incorporate the effect of near-bed sediment processes and yielded reasonable agreement. This parameterization yielded the best agreement at the bar trough, with a coefficient of determination R2 ≥ 0.72 above the bottom boundary layer. The time-averaged SSC in the inner surf zone showed good agreement near the bed but poor agreement near the water surface, suggesting that there is a different sedimentation mechanism that controls the SSC in the inner surf zone.

A hydrodynamic model of nearshore waves and wave-induced currents

Directory of Open Access Journals (Sweden)

Ahmed Khaled Seif

2011-09-01

Full Text Available In This study develops a quasi-three dimensional numerical model of wave driven coastal currents with accounting the effects of the wave-current interaction and the surface rollers. In the wave model, the current effects on wave breaking and energy dissipation are taken into account as well as the wave diffraction effect. The surface roller associated with wave breaking was modeled based on a modification of the equations by Dally and Brown (1995 and Larson and Kraus (2002. Furthermore, the quasi-three dimensional model, which based on Navier-Stokes equations, was modified in association with the surface roller effect, and solved using frictional step method. The model was validated by data sets obtained during experiments on the Large Scale Sediment Transport Facility (LSTF basin and the Hazaki Oceanographical Research Station (HORS. Then, a model test against detached breakwater was carried out to investigate the performance of the model around coastal structures. Finally, the model was applied to Akasaki port to verify the hydrodynamics around coastal structures. Good agreements between computations and measurements were obtained with regard to the cross-shore variation in waves and currents in nearshore and surf zone.

Spatial and temporal analysis of lake sedimentation under reforestation

Directory of Open Access Journals (Sweden)

C.M. Pilgrim

2015-10-01

Full Text Available Spatial and temporal land cover changes can reduce or accelerate lake sedimentation. This study was conducted to examine morphometry and bathymetry, and the long-term changes (over 75 years in sedimentation in the Lake Issaqueena reservoir, South Carolina. The watershed and catchment areas were delineated using Light Detection and Ranging (LiDAR based data. Trends in lake surface area and riparian buffer condition (vegetated or unvegetated were determined from historical aerial photography. From 1938 to 2009, the lake experienced a decrease in surface area of approximately 11.33 ha while catchment area increased by 6.99 ha, and lake volume decreased by 320,800.00 m3. Lake surface area decreased in years corresponding to equal coverage or largely unvegetated riparian buffers. Surface area and average annual precipitation were not correlated; therefore other factors such as soil type, riparian buffer condition and changes in land use likely contributed to sedimentation. Shift from agricultural land to forestland in this watershed resulted in a decrease in sedimentation rates by 88.28%. Keywords: Bathymetry, Erosion, Geographic Information Systems (GIS, Land cover, Riparian buffer, Soils

Progress towards the Conventionon Biological Diversity terrestrial2010 and marine 2012 targets forprotected area coverage

DEFF Research Database (Denmark)

Coad, Lauren; Burgess, Neil David; Fish, Lucy

2010-01-01

coverage targets. National protected areas data from the WDPA have been used to measure progress in protected areas coverage at global, regional and national scale. The mean protected area coverage per nation was 12.2% for terrestrial area, and only 5.1% for near-shore marine area. Variation in protected......Protected area coverage targets set by the Convention on Biological Diversity (CBD) for both terrestrial and marine environments provide a major incentive for governments to review and upgrade their protected area systems. Assessing progress towards these targets will form an important component...... of the work of the Xth CBD Conference of Parties meeting to be held in Japan in 2010. The World Database on Protected Areas (WDPA) is the largest assembly of data on the world's terrestrial and marine protected areas and, as such, represents a fundamental tool in tracking progress towards protected area...

Airborne Gravimetry Survey for the Marine Area of the United Arab Emirates

DEFF Research Database (Denmark)

Forsberg, René; Olesen, Arne Vestergaard; Alshamsi, Adel

2012-01-01

The Military Survey Department (MSD) of the United Arab Emirates (UAE) undertook an airborne gravity survey project for the marine area of the country in 2009, especially to strengthen the marine and coastal geoid in the near-shore regions. For the airborne gravity survey, 5 km spacing coast...... flight speed of 170 knots and a typical flight elevation of 900-1500 m, depending on weather conditions and topography. Gravity was measured with a ZLS-modified LaCoste and Romberg gravimeter (S-99), augmented with a Honeywell strap-down inertial navigation system unit. The estimated accuracy...

Community structure of fish larvae in mangroves with different root types in Labuhan coastal area, Sepulu - Madura

Science.gov (United States)

Muzaki, Farid Kamal; Giffari, Aninditha; Saptarini, Dian

2017-06-01

Mangrove root complexity and shading are well known to give positive correlation for both juveniles and adult fishes. However, it is remain unclear whether that complexity would affect the community of fish larvae (ichthyoplankton). This study aimed to address the question, especially in mangrove area in coastal area of Sepulu, Madura which projected as a mangrove protection area. Sampling periods were from March to May, 2016. The samples of fish larvae were collected by plankton net (mesh-size 0.150 and 0.265 mm) from six different locations representing different root types (stilt root, pneumatophore, combination of stilt root-pneumatophore and unvegetated area). As the results, 6 families were identified, namely Gobiidae, Blennidae, Pomacentridae, Carangidae, Engraulidae and Ambassidae, respectively. Gobiidae seems to be the most abundant and widely dispersed in the area. Results of two-way AnovadanTukey HSD (both at p=0.05) indicate that there were significant difference in the larval abundance regarding locations, sampling periods and interaction of both factors. As for number of taxa, significant difference occurred only from factors of locations and sampling periods, but not for interaction of both factors. Highest larval abundance and number of taxa occurred in Rhizophoraspp (with stilt root), indicating that root complexity would affect the community of fish larvae. Ordination by canonical analysis shows that different taxa of the fish larvae are tend to be distributed on different locations.

Organic Geochemistry of Sediments in Nearshore Areas of the Mississippi and Atchafalaya Rivers: I. General Organic Characterization

Science.gov (United States)

Orem, William H.; Rosenbauer, Robert J.; Swarzenski, Peter W.; Lerch, Harry E.; Corum, Margo D.; Bates, Anne L.

2007-01-01

This report presents results on the general organic characteristics of sediment cores collected from the coastal zone of the Mississippi River system, including distributions of the important nutrient elements (C, N, P, and S). This was part of a larger study conducted from 2001-2005 to examine the delivery of sediment-associated contaminants to the Gulf of Mexico by the Mississippi River system, funded by the USGS Coastal and Marine Geology Program. Companion reports emphasize organic contaminants (Rosenbauer and others, 2006), and metals (Swarzenski and others, 2006). The level of contamination within the deltaic system of the Mississippi River system was determined through the collection of sediment cores from interdistributary bays, and offshore in the Gulf of Mexico, including the zone of hypoxia. Results provide the basis for reconstructing contaminant inventories from which to develop historic perspectives on nutrient loading and hypoxia, and to better understand how sediment-hosted contaminants either directly or indirectly move through biota and ultimately affect ecosystem health. Concentrations of C, N, P, and S in sediments varied by a factor of 10 between sites, and in down core profiles. Nearshore cores collected in 2001 proved to have erratic downcore C, N, P, and S profiles and sediment deposition rates, suggesting a high energy regime controlled more by variability in river flow rather than by geochemical processes and reactions within the system. These results focused further coring activities further offshore. Atomic C/N ratios suggest that organic matter deposited at all sites is a mix of microbial (algal) and terrestrial (vascular plant) remains, but with algal material dominant. Concentrations of total sulfur in sediments from cores in the zone of hypoxia were often higher than those in nearby zones with oxic water columns. Corresponding atomic C/S ratios were typically lower in sediments from sites in the zone of hypoxia compared to nearby

Water temperature, salinity and other profiles from CTD taken from near-shore well in Puerto Morelos from 2014-03-27 to 2014-03-28 (NCEI Accession 0163741)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is a 12-hr time series of CTD profiles of water temperature and salinity taken from near-shore well in Puerto Morelos from 2014-03-27 to 2014-03-28. Data were...

Predominant Nearshore Sediment Dispersal Patterns in Manila Bay

Directory of Open Access Journals (Sweden)

Fernando Siringan

1997-12-01

Full Text Available Net nearshore sediment drift patterns in Manila Bay were determined by combining the coastal geomorphology depicted in 1 : 50,000scale topographic maps and Synthetic Aperture Radar (SAR images, with changes in shoreline position and predominant longshore current directions derived from the interaction of locally generated waves and bay morphology.Manila Bay is fringed by a variety of coastal subenvironments that reflect changing balances of fluvial, wave, and tidal processes. Along the northern coast, a broad tidal-river delta plain stretching from Bataan to Bulacan indicates the importance of tides, where the lateral extent of tidal influences is amplified by the very gentle coastal gradients. In contrast, along the Cavite coast sandy strandplains, spits, and wave-dominated deltas attest to the geomorphic importance of waves that enter the bay from the South China Sea.The estimates of net sediment drift derived from geomorphological, shoreline-change, and meteorological information are generally in good agreement. Sediment drift directions are predominantly to the northeast along Cavite, to the northwest along Manila and Bulacan, and to the north along Bataan. Wave refraction and eddy formation at the tip of the Cavite Spit cause southwestward sediment drift along the coast from Zapote to Kawit. Geomorphology indicates that onshore-offshore sediment transport is probably more important than alongshore transport along the coast fronting the tidal delta plain of northern Manila Bay. Disagreements between the geomorphic-derived and predicted net sediment drift directions may be due to interactions of wave-generated longshore currents with wind- and tide-generated currents.

Cross-shelf transport into nearshore waters due to shoaling internal tides in San Pedro Bay, CA

Science.gov (United States)

Noble, Marlene A.; Burt Jones,; Peter Hamilton,; Xu, Jingping; George Robertson,; Rosenfeld, Leslie; John Largier,

2009-01-01

In the summer of 2001, a coastal ocean measurement program in the southeastern portion of San Pedro Bay, CA, was designed and carried out. One aim of the program was to determine the strength and effectiveness of local cross-shelf transport processes. A particular objective was to assess the ability of semidiurnal internal tidal currents to move suspended material a net distance across the shelf. Hence, a dense array of moorings was deployed across the shelf to monitor the transport patterns associated with fluctuations in currents, temperature and salinity. An associated hydrographic program periodically monitored synoptic changes in the spatial patterns of temperature, salinity, nutrients and bacteria. This set of measurements show that a series of energetic internal tides can, but do not always, transport subthermocline water, dissolved and suspended material from the middle of the shelf into the surfzone. Effective cross-shelf transport occurs only when (1) internal tides at the shelf break are strong and (2) subtidal currents flow strongly downcoast. The subtidal downcoast flow causes isotherms to tilt upward toward the coast, which allows energetic, nonlinear internal tidal currents to carry subthermocline waters into the surfzone. During these events, which may last for several days, the transported water remains in the surfzone until the internal tidal current pulses and/or the downcoast subtidal currents disappear. This nonlinear internal tide cross-shelf transport process was capable of carrying water and the associated suspended or dissolved material from the mid-shelf into the surfzone, but there were no observation of transport from the shelf break into the surfzone. Dissolved nutrients and suspended particulates (such as phytoplankton) transported from the mid-shelf into the nearshore region by nonlinear internal tides may contribute to nearshore algal blooms, including harmful algal blooms that occur off local beaches.

Nearshore fish survey in northern Bristol Bay, Alaska conducted from 2009-07 to 2009-08 by Alaska Fisheries Science Center, Resource Ecology and Fisheries Management division (NCEI Accession 0144625)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The project consisted of a nearshore fish, invertebrate, and habitat survey in northern Bristol Bay, Alaska. A 32-ft. gillnet vessel, the F/V Willow was chartered...

Understanding Nearshore Processes Of a Large Arctic Delta Using Combined Seabed Mapping, In Situ Observations, Remote Sensing and Modeling

Science.gov (United States)

Solomon, S. M.; Couture, N. J.; Forbes, D. L.; Hoque, A.; Jenner, K. A.; Lintern, G.; Mulligan, R. P.; Perrie, W. A.; Stevens, C. W.; Toulany, B.; Whalen, D.

2009-12-01

The Mackenzie River Delta and the adjacent continental shelf in the southeastern Beaufort Sea are known to host significant quantities of hydrocarbons. Recent environmental reviews of proposed hydrocarbon development have highlighted the need for a better understanding of the processes that control sediment transport and coastal stability. Over the past several years field surveys have been undertaken in winter, spring and summer to acquire data on seabed morphology, sediment properties, sea ice, river-ocean interaction and nearshore oceanography. These data are being used to improve conceptual models of nearshore processes and to develop and validate numerical models of waves, circulation and sediment transport. The timing and location of sediment erosion, transport and deposition is complex, driven by a combination of open water season storms and spring floods. Unlike temperate counterparts, the interaction between the Mackenzie River and the Beaufort Sea during spring freshet is mediated by the presence of ice cover. Increasing discharge exceeds the under-ice flow capacity leading to flooding of the ice surface, followed by vortex drainage through the ice and scour of the seabed below (“strudel” drainage and scour). During winter months, nearshore circulation slows beneath a thickening ice canopy. Recent surveys have shown that the low gradient inner shelf is composed of extensive shoals where ice freezes to the seabed and intervening zones which are slightly deeper than the ice is thick. The duration of ice contact with the bed determines the thermal characteristics of the seabed. Analysis of cores shows that the silts comprising the shoals are up to 6 m thick. The predominantly well sorted and cross-laminated nature of the silts at the top of the cores suggests an active delta front environment. Measurements of waves, currents, conductivity, temperature and sediment concentration during spring and late summer have been acquired. During moderate August

Distribution of Euphausia mucronata at the upwelling area of Peninsula Mejillones, northern Chile: The influence of the oxygen minimum layer

Directory of Open Access Journals (Sweden)

R. Escribano

2000-03-01

Full Text Available Analysis of zooplankton samples from 53 stations obtained around Peninsula Mejillones (Northern Chile, from two strata: 0-50 m and 150-200 m, during active upwelling in December 1996, allowed the study of horizontal and vertical distribution of Euphausia mucronata, endemic Krill of the Humboldt Current. Information from CTDO and a fluorometer was used to analyze the influence of oceanographic variables on distribution of E. mucronata. E. mucronata was found distributed all around the Peninsula, although with greater aggregations in the southern area, especially in the deeper layer. Stepwise multiple regression showed that none of the variables (temperature, salinity and chlorophyll was significantly correlated to numerical abundance of the species. However there was a significant effect of depth of the oxygen minimum layer (OML, defined as 0.5 ml O2 l-1, on integrated abundance of the species, such that individuals are more likely to be found in areas where the OML is deeper. A vertical distribution parameter suggested a diurnal migrational pattern. This parameter was also correlated with distance to shoreline. The OML rises abrutply in nearshore areas because of active upwelling, but there are still nearshore zones where the OML remains deep. Therefore E. mucronata appears to aggregate around the upwelling lenses and filaments, where phytoplankton is more concentrated, but at the same time avoiding places where the OML is too shallow.

Oil pollution in the Red Sea - Environmental monitoring of an oilfield in a Coral area, Gulf of Suez

Energy Technology Data Exchange (ETDEWEB)

Dicks, B

1984-01-01

The Red Sea is rapidly developing as one of the world's largest offshore oil production areas. It also comprises a wide range of tropical marine habitats, many of which are internationally recognised for their conservation, scientific, economic or recreational value. Past oil production, refining and transport have resulted in chronic pollution of some areas, and environmental programmes to protect new areas of development from pollution damage are assuming increasing importance. At the initiative of an Egyptian oil company operating in the Gulf of Suez, an environmental protection and management scheme has been prepared for a new offshore oilfield and marine terminal at Ras Budran. This paper describes the form of the scheme and the results of its component environmental surveys. The development area comprises rich and diverse marine communities of fringing coral reefs, nearshore lagoons, seagrass beds, sandy beaches and fine sediments offshore. A baseline survey was designed following detailed discussion of the scope of the development with the company and a preliminary site visit, and the fieldwork was completed in October 1980. On the basis of the findings of the survey, a series of recommendations was made to the company, aimed at reducing environmental impacts during construction and operation to a minimum and acceptable level. These were subsequently implemented and the results of a post-construction survey in February 1983 are reported which show that environmental damage to the nearshore habitats during the construction phase had been relatively small and localised. Recently, the biological information obtained from the two surveys has also been incorporated into oil spill contingency plans.

Inferred fish behavior its implications for hydroacoustic surveys in nearshore habitats

Science.gov (United States)

DuFour, Mark R.; Mayer, Christine M.; Qian, Song S.; Vandergoot, Christopher; Kraus, Richard T.; Kocovsky, Patrick; Warner, David M.

2018-01-01

Population availability and vessel avoidance effects on hydroacoustic abundance estimates may be scale dependent; therefore, it is important to evaluate these biases across systems. We performed an inter-ship comparison survey to determine the effect of vessel size, day-night period, depth, and environmental gradients on walleye (Sander vitreus) density estimates in Lake Erie, an intermediate-scaled system. Consistent near-bottom depth distributions coupled with horizontal fish movements relative to vessel paths indicated avoidance behavior contributed to higher walleye densities from smaller vessels in shallow water (i.e., <15 m), although the difference decreased with increasing depth. Diel bank migrations in response to seasonally varying onshore-to-offshore environmental gradients likely contributed to day-night differences in densities between sampling locations and seasons. Spatial and unexplained variation accounted for a high proportion of total variation; however, increasing sampling intensity can mitigate effects on precision. Therefore, researchers should minimize systematic avoidance and availability related biases (i.e., vessel and day-night period) to improve population abundance estimates. Quantifying availability and avoidance behavior effects and partitioning sources of variation provides informed flexibility for designing future hydroacoustic surveys in shallow-water nearshore environments.

An efficient mode-splitting method for a curvilinear nearshore circulation model

Science.gov (United States)

Shi, Fengyan; Kirby, James T.; Hanes, Daniel M.

2007-01-01

A mode-splitting method is applied to the quasi-3D nearshore circulation equations in generalized curvilinear coordinates. The gravity wave mode and the vorticity wave mode of the equations are derived using the two-step projection method. Using an implicit algorithm for the gravity mode and an explicit algorithm for the vorticity mode, we combine the two modes to derive a mixed difference–differential equation with respect to surface elevation. McKee et al.'s [McKee, S., Wall, D.P., and Wilson, S.K., 1996. An alternating direction implicit scheme for parabolic equations with mixed derivative and convective terms. J. Comput. Phys., 126, 64–76.] ADI scheme is then used to solve the parabolic-type equation in dealing with the mixed derivative and convective terms from the curvilinear coordinate transformation. Good convergence rates are found in two typical cases which represent respectively the motions dominated by the gravity mode and the vorticity mode. Time step limitations imposed by the vorticity convective Courant number in vorticity-mode-dominant cases are discussed. Model efficiency and accuracy are verified in model application to tidal current simulations in San Francisco Bight.

Differing effects of eelgrass Zostera marina on recruitment and growth of associated blue mussels Mytilus edulis

NARCIS (Netherlands)

Reusch, B.H.T.

1998-01-01

I studied the effects of habitat structure, provided by an eelgrass Zostera marina canopy, on shell growth rate and recruitment of co-occurring blue mussels Mytilus edulis in the Western Baltic Sea. M. edulis in clumps consisting of 10 and 30 individuals were tagged and placed in unvegetated areas

Gas-charged sediments in shallow waters off Redi along the central west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Subbaraju, L.V.; Wagle, B.G.

This study reports the occurrence of gas-charged sediments in the nearshore areas of the west coast of India. High resolution shallow seismic reflection profiles on the nearshore area along central west coast of India, at water depths of 11-18 m...

Integration of Web-GIS and oil spill simulation applications for environmental management of near-shore spill accidents

International Nuclear Information System (INIS)

Goto, S.; Miyata, D.; Varlamov, S.M.; Kim, S.-W.

2001-01-01

In the event of a near-shore oil spill, the use of a web-based Geographic Information System (GIS) can greatly improve emergency response management and oil recovery operations by providing real-time information support. This paper presented a Web-GIS that is used in combination with an oil spill simulation model. The structure and content of the system was defined after the Nakhodka vessel spilled oil in the Sea of Japan in January 1997, leaving serious environmental damage to the coastal area of the Ishikawa prefecture. The Web-GIS provides a wide range of environmental and oil spill related information, presented in a geographical form. The system also consolidates spill and environmental damage related information from different sources and provides links to the specialized environmental and socio-economical information of other GIS databases. The oil spill modeling subsystem is part of an application for protection planning and oil recovery operations. With this system, oil-drift simulation begins at the onset of any oil spill and then remote sensing data are used to estimate the position and state of the spilled oil. The spill information is then assimilated into the spill model and the observed simulated results are uploaded to the Web page for public information. The applicability of the Web-GIS is extended by support for information gathering from the public and the responsible agencies. The relative simplicity of the system interface is an added advantage. 9 refs., 4 figs

The first US National Coastal Condition Assessment survey in the Great Lakes: Development of the GIS frame and exploration of spatial variation in nearshore water quality results

Science.gov (United States)

A comprehensive approach to assess conditions in the Great Lakes nearshore zone has been lacking for decades. We had the opportunity to conduct a pilot survey in Lake Erie (45 sites) in summer 2009 and to develop a full survey across the 5 lakes (~400 sites) as part of the US N...

Pliocene diatoms from the Bryce Canyon Area, Utah

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A.P.

habitat. The fragmentary condition of these indicated agitation during sedimentation. The ratio between the planktonic and benthonic diatoms indicated near-shore deposition. The two extinct species (?), @iSurirella craticula@@ (= @iStictodesmis craticula...

Recently Discovered Near-Shore Gascharged Sediments and Pockmarks, Northern Iceland

Science.gov (United States)

Richter, B.; Driscol, N.; Detrick, R. S.; Fornari, D.; Brandsdottir, B.

2003-12-01

The approx. 150 km long and 50 km wide Tjornes Fracture Zone (TFZ), formed in response to the eastward jump of the spreading axis in N-Iceland that began in late Miocene time (7-9 Ma). The fracture zone is made up of three N-S trending extensional half graben, Eyjafjordur, Skjalfandi and Oxarfjordur, and bordered to the south by a WNW-trending transtensional fault, the Husavik-Flatey fault (HFF). A 0.5-4 km thick sedimentary sequence has accumulated within the TFZ graben. Near-shore marine sediments are exposed on the Tjornes peninsula, at the eastern margin of the Skjalfandi graben, where approx. 500 m thick Miocene-Pliocene sediments contain several lignite layers. Natural gas emitting from geothermal areas at the shore of Oxarfjordur contain high concentrations of evolved hydrocarbons. The gas probably originates from marine sediments and lignites similar to those observed on the Tjornes peninsula. In 2001, a sidescan sonar imaging and CHIRP subbottom profiling were conducted along the HFF, within Skjalfandi Bay. CHIRP data show amplitude anomalies and acoustic wipe-out zones, indicative of gas accumulation within the sediments. In addition, the sidescan data reveal a number of shallow, circular and elongated depressions up to 30 m in diameter along the northern edge of the HFF. Areas of large, elongated and circular depressions (pockmarks) within Skjalfandi Bay were mapped during a multibeam bathymetric survey in 2002. A second Chirp subbottom and sidescan-sonar survey was conducted this summer along with gravity coring and digital bottom photography in order to assess the origin of these pockmarks and define the distribution of the gas charged sediments. Where present, acoustic wipe-out zones associated with the gas obscured all underlying reflectors as shallow as 5 meters below the ocean floor, in areas as large as 2 square km. The gas charged sediments are more widespread than previously observed within the bay. In northern Skjalfandi the gas seems connected

Implementing Engineering With Nature within the Corps: A Workshop

Science.gov (United States)

2013-09-01

mercury in fish: lessons from a hydropower storage basin: Dr. Jody A. Kubitz, Cardno... algae on SAV leaves, eventually leading to their death. As a result, breakwater‐protected areas are often unvegetated, especially after deposition of...from the DCF to allow determination of appropriate sediment disposal (lined landfill disposal or commercial industrial use). ERDC

Effectiveness of vegetated constructed wetland in the reducation of ...

African Journals Online (AJOL)

Also, the root zone increased the surface area thereby increasing the contact between micro-organisms and the pollutants to be destroyed. The removal of BOD5 in the unvegetated CW unit A suggests that in CW systems, gravitational settling of solids is also a predominant removal mechanism of BOD5. Journal of Building ...

Impact of sampling depth and plant species on local environmental conditions, microbiological parameters and bacterial composition in a mercury contaminated salt marsh

International Nuclear Information System (INIS)

Cleary, D.F.R.; Oliveira, V.; Gomes, N.C.M.; Pereira, A.; Henriques, I.; Marques, B.; Almeida, A.; Cunha, A.; Correia, A.; Lillebø, A.I.

2012-01-01

Highlights: ► Vegetated habitat contained distinct bacterial communities. ► Variation in bacterial composition with depth differed between plant species. ► There is evidence of an effect of mercury concentration on bacterial composition. ► Depth and sampling depth explained almost 70% of the variation in bacterial composition. - Abstract: We compare the environmental characteristics and bacterial communities associated with two rushes, Juncus maritimus and Bolboschoenus maritimus, and adjacent unvegetated habitat in a salt marsh subjected to historical mercury pollution. Mercury content was higher in vegetated than unvegetated habitat and increased with sampling depth. There was also a significant relationship between mercury concentration and bacterial composition. Habitat (Juncus, Bolboschoenus or unvegetated), sample depth, and the interaction between both, however, explained most of the variation in composition (∼70%). Variation in composition with depth was most prominent for the unvegetated habitat, followed by Juncus, but more constrained for Bolboschoenus habitat. This constraint may be indicative of a strong plant–microbe ecophysiological adaptation. Vegetated habitat contained distinct bacterial communities associated with higher potential activity of aminopeptidase, β-glucosidase and arylsulphatase and incorporation rates of 14 C-glucose and 14 C-acetate. Communities in unvegetated habitat were, in contrast, associated with both higher pH and proportion of sulphate reducing bacteria.

Mapping South Baltic Near-Shore Bathymetry Using Sentinel-2 Observations

Directory of Open Access Journals (Sweden)

Chybicki Andrzej

2017-09-01

Full Text Available One of the most promising new applications of remote observation satellite systems (RO is the near-shore bathymetry estimation based on spaceborn multispectral imageries. In recent years, many experiments aiming to estimate bathymetry in optically shallow water with the use of remote optical observations have been presented. In this paper, optimal models of satellite derived bathymetry (SDB for relatively turbid waters of the South Baltic Sea were presented. The obtained results were analysed in terms of depth error estimation, spatial distribution, and overall quality. The models were calibrated based on sounding (in-situ data obtained by a single-beam echo sounder, which was retrieved from the Maritime Office in Gdynia, Poland. The remote observations for this study were delivered by the recently deployed European Space Agency Sentinel-2 satellite observation system. A detailed analysis of the obtained results has shown that the tested methods can be successfully applied for the South Baltic region at depths of 12-18 meters. However, significant limitations were observed. The performed experiments have revealed that the error of model calibration, expressed in meters (RMSE, equals up to 10-20% of the real depth and is, generally, case dependent. To overcome this drawback, a novel indicator of determining the maximal SDB depth was proposed. What is important, the proposed SDB quality indicator is derived only on the basis of remotely registered data and therefore can be applied operationally.

Benthic habitat map of the U.S. Coral Reef Task Force Watershed Partnership Initiative Kā'anapali priority study area and the State of Hawai'i Kahekili Herbivore Fisheries Management Area, west-central Maui, Hawai'i

Science.gov (United States)

Cochran, Susan A.; Gibbs, Ann E.; White, Darla J.

2014-01-01

Nearshore areas off of west-central Maui, Hawai‘i, once dominated by abundant coral coverage, now are characterized by an increased abundance of turf algae and macroalgae. In an effort to improve the health and resilience of the coral reef system, the Kahekili Herbivore Fisheries Management Area was established by the State of Hawai‘i, and the U.S. Coral Reef Task Force selected the Kā‘anapali region as a priority study area. To support these efforts, the U.S. Geological survey mapped nearly 5 km2 of sea floor from the shoreline to water depths of about 30 m. Unconsolidated sediment (predominantly sand) constitutes 65 percent of the sea floor in the mapped area. Reef and other hardbottom potentially available for coral recruitments constitutes 35 percent of the mapped area. Of this potentially available hardbottom, only 51 percent is covered with a minimum of 10 percent coral, and most is found between 5 and 10 m water depth.

Long-term effects of submergence and wetland vegetation on metals in a 90-year old abandoned Pb-Zn mine tailings pond

International Nuclear Information System (INIS)

Jacob, Donna L.; Otte, Marinus L.

2004-01-01

A Pb-Zn tailings pond, abandoned for approximately 90 years, has been naturally colonized by Glyceria fluitans and is an excellent example of long-term metal retention in tailings ponds under various water cover and vegetation conditions. Shallow/intermittently flooded areas (dry zone) were unvegetated and low in organic matter (OM) content. Permanently flooded areas were either unvegetated with low OM, contained dead vegetation and high OM, or living plants and high OM. It was expected that either water cover or high OM would result in enhanced reducing conditions and lower metal mobility, but live plants would increase metal mobility due to root radial oxygen loss. The flooded low OM tailings showed higher As and Fe mobility compared with dry low OM tailings. In the permanently flooded areas without live vegetation, the high OM content decreased Zn mobility and caused extremely high concentrations of acid-volatile sulfides (AVS). In areas with high OM, living plants significantly increased Zn mobility and decreased concentrations of AVS, indicating root induced sediment oxidation or decreased sulfate-reduction. This is the first study reporting the ability of wetland plants to affect the metal mobility and AVS in long-term (decades), unmanaged tailings ponds. - Metal and acid-volatile sulfide concentrations were affected differently by flooding vegetation

Marine protected areas in Costa Rica: How do artisanal fishers respond?

Science.gov (United States)

Madrigal-Ballestero, Róger; Albers, Heidi J; Capitán, Tabaré; Salas, Ariana

2017-11-01

Costa Rica is considering expanding their marine protected areas (MPAs) to conserve marine resources. Due to the importance of households' responses to an MPA in defining the MPA's ecological and economic outcomes, this paper uses an economic decision framework to interpret data from near-MPA household surveys to inform this policy discussion. The model and data suggest that the impact of expanding MPAs relies on levels of enforcement and on-shore wages. If larger near-shore MPAs can produce high wages through increased tourism, MPA expansions could provide ecological benefits with low burdens to communities. Due to distance costs and gear investments, however, MPAs farther off-shore may place high burdens on off-shore fishers.

The Role of Near-Shore Bathymetry During Tsunami Inundation in a Reef Island Setting: A Case Study of Tutuila Island

Science.gov (United States)

Dilmen, Derya I.; Roe, Gerard H.; Wei, Yong; Titov, Vasily V.

2018-04-01

On September 29, 2009 at 17:48 UTC, an M w = 8.1 earthquake in the Tonga Trench generated a tsunami that caused heavy damage across Samoa, American Samoa, and Tonga. One of the worst hits was the volcanic island of Tutuila in American Samoa. Tutuila has a typical tropical island bathymetry setting influenced by coral reefs, and so the event provided an opportunity to evaluate the relationship between tsunami dynamics and the bathymetry in that typical island environment. Previous work has come to differing conclusions regarding how coral reefs affect tsunami dynamics through their influence on bathymetry and dissipation. This study presents numerical simulations of this event with a focus on two main issues: first, how roughness variations affect tsunami run-up and whether different values of Manning's roughness parameter, n, improve the simulated run-up compared to observations; and second, how depth variations in the shelf bathymetry with coral reefs control run-up and inundation on the island coastlines they shield. We find that no single value of n provides a uniformly good match to all observations; and we find substantial bay-to-bay variations in the impact of varying n. The results suggest that there are aspects of tsunami wave dissipation which are not captured by a simplified drag formulation used in shallow-water waves model. The study also suggests that the primary impact of removing the near-shore bathymetry in coral reef environment is to reduce run-up, from which we conclude that, at least in this setting, the impact of the near-shore bathymetry is to increase run-up and inundation.

The Role of Near-Shore Bathymetry During Tsunami Inundation in a Reef Island Setting: A Case Study of Tutuila Island

Science.gov (United States)

Dilmen, Derya I.; Roe, Gerard H.; Wei, Yong; Titov, Vasily V.

2018-02-01

On September 29, 2009 at 17:48 UTC, an M w = 8.1 earthquake in the Tonga Trench generated a tsunami that caused heavy damage across Samoa, American Samoa, and Tonga. One of the worst hits was the volcanic island of Tutuila in American Samoa. Tutuila has a typical tropical island bathymetry setting influenced by coral reefs, and so the event provided an opportunity to evaluate the relationship between tsunami dynamics and the bathymetry in that typical island environment. Previous work has come to differing conclusions regarding how coral reefs affect tsunami dynamics through their influence on bathymetry and dissipation. This study presents numerical simulations of this event with a focus on two main issues: first, how roughness variations affect tsunami run-up and whether different values of Manning's roughness parameter, n, improve the simulated run-up compared to observations; and second, how depth variations in the shelf bathymetry with coral reefs control run-up and inundation on the island coastlines they shield. We find that no single value of n provides a uniformly good match to all observations; and we find substantial bay-to-bay variations in the impact of varying n. The results suggest that there are aspects of tsunami wave dissipation which are not captured by a simplified drag formulation used in shallow-water waves model. The study also suggests that the primary impact of removing the near-shore bathymetry in coral reef environment is to reduce run-up, from which we conclude that, at least in this setting, the impact of the near-shore bathymetry is to increase run-up and inundation.

234Th/238U disequilibrium in near-shore sediment: particle reworking and diagenetic time scales

International Nuclear Information System (INIS)

Aller, R.C.; Cochran, J.K.

1976-01-01

The distribution of 234 Th (tsub(1.2)=24.1 days) in excess of its parent 238 U in the upper layers of near-shore sediment makes possible the evaluation of short-term sediment reworking and diagenetic rates. 234 Th has a maximum residence time in Long Island Sound water of 1.4 days. Seasonal measurement of 234 Th/ 238 U disequilibrium in sediment at a single station in central Long Island Sound demonstrates rapid particle reworking and high 234 Thsub(XS)(>1 dpm/g) in the upper 4 cm of sediment with slower, irregular reworking and low 234 Thsub(XS) to at least 12 cm. The rate of rapid particle reworking varies seasonally and is highest in the fall. The rapidly mixed zone is characterized by steep gradients in sediment chemistry implying fast reactions spanned by 234 Th decay time scales. 238 U is depleted in the upper mixed zone and shows addition in reducing sediment at depth. (Auth.)

Benthic status of near-shore fishing grounds in the central Philippines and associated seahorse densities.

Science.gov (United States)

Marcus, J E; Samoilys, M A; Meeuwig, J J; Villongco, Z A D; Vincent, A C J

2007-09-01

Benthic status of 28 near-shore, artisanal, coral reef fishing grounds in the central Philippines was assessed (2000-2002) together with surveys of the seahorse, Hippocampus comes. Our measures of benthic quality and seahorse densities reveal some of the most degraded coral reefs in the world. Abiotic structure dominated the fishing grounds: 69% of the benthos comprised rubble (32%), sand/silt (28%) and dead coral (9%). Predominant biotic structure included live coral (12%) and Sargassum (11%). Rubble cover increased with increasing distance from municipal enforcement centers and coincided with substantial blast fishing in this region of the Philippines. Over 2 years, we measured a significant decrease in benthic 'heterogeneity' and a 16% increase in rubble cover. Poor benthic quality was concomitant with extremely low seahorse densities (524 fish per km(2)). Spatial management, such as marine reserves, may help to minimize habitat damage and to rebuild depleted populations of seahorses and other reef fauna.

Spectral Wave Characteristics in the Nearshore Waters of Northwestern Bay of Bengal

Science.gov (United States)

Anjali Nair, M.; Sanil Kumar, V.; Amrutha, M. M.

2018-03-01

The spectral wave characteristics in the nearshore waters of northwestern Bay of Bengal are presented based on the buoy-measured data from February 2013 to December 2015 off Gopalpur at 15-m water depth. The mean seasonal significant wave height and mean wave period indicate that the occurrence of higher wave heights and wave periods is during the southwest monsoon period (June-September). 74% of the sea surface height variance in a year is a result of waves from 138 to 228° and 16% are from 48 to 138°. Strong inter-annual variability is observed in the monthly average wave parameters due to the occurrence of tropical cyclones. Due to the influence of the tropical cyclone Phailin, maximum significant wave height of 6.7 m is observed on 12 October 2013 and that due to tropical cyclone Hudhud whose track is 250 southwest of the study location is 5.84 m on 12 October 2014. Analysis revealed that a single tropical cyclone influenced the annual maximum significant wave height and not the annual average value which is almost same ( 1 m) in 2014 and 2015. The waves in the northwestern Bay of Bengal are influenced by the southwest and northeast monsoons, southern ocean swells and cyclones.

Human impacts on large benthic foraminifers near a densely populated area of Majuro Atoll, Marshall Islands

International Nuclear Information System (INIS)

Osawa, Yoko; Fujita, Kazuhiko; Umezawa, Yu; Kayanne, Hajime; Ide, Yoichi; Nagaoka, Tatsutoshi; Miyajima, Toshihiro; Yamano, Hiroya

2010-01-01

Human impacts on sand-producing, large benthic foraminifers were investigated on ocean reef flats at the northeast Majuro Atoll, Marshall Islands, along a human population gradient. The densities of dominant foraminifers Calcarina and Amphistegina declined with distance from densely populated islands. Macrophyte composition on ocean reef flats differed between locations near sparsely or densely populated islands. Nutrient concentrations in reef-flat seawater and groundwater were high near or on densely populated islands. δ 15 N values in macroalgal tissues indicated that macroalgae in nearshore lagoons assimilate wastewater-derived nitrogen, whereas those on nearshore ocean reef flats assimilate nitrogen from other sources. These results suggest that increases in the human population result in high nutrient loading in groundwater and possibly into nearshore waters. High nutrient inputs into ambient seawater may have both direct and indirect negative effects on sand-producing foraminifers through habitat changes and/or the collapse of algal symbiosis.

Oligotrophic wetland sediments susceptible to shifts in microbiomes and mercury cycling with dissolved organic matter addition

Directory of Open Access Journals (Sweden)

Emily B. Graham

2018-04-01

Full Text Available Recent advances have allowed for greater investigation into microbial regulation of mercury toxicity in the environment. In wetlands in particular, dissolved organic matter (DOM may influence methylmercury (MeHg production both through chemical interactions and through substrate effects on microbiomes. We conducted microcosm experiments in two disparate wetland environments (oligotrophic unvegetated and high-C vegetated sediments to examine the impacts of plant leachate and inorganic mercury loadings (20 mg/L HgCl2 on microbiomes and MeHg production in the St. Louis River Estuary. Our research reveals the greater relative capacity for mercury methylation in vegetated over unvegetated sediments. Further, our work shows how mercury cycling in oligotrophic unvegetated sediments may be susceptible to DOM inputs in the St. Louis River Estuary: unvegetated microcosms receiving leachate produced substantially more MeHg than unamended microcosms. We also demonstrate (1 changes in microbiome structure towards Clostridia, (2 metagenomic shifts toward fermentation, and (3 degradation of complex DOM; all of which coincide with elevated net MeHg production in unvegetated microcosms receiving leachate. Together, our work shows the influence of wetland vegetation in controlling MeHg production in the Great Lakes region and provides evidence that this may be due to both enhanced microbial activity as well as differences in microbiome composition.

Fish assemblage dynamics in a Neotropical floodplain relative to aquatic macrophytes and the homogenizing effect of a flood pulse

Science.gov (United States)

Gomes, L.C.; Bulla, C. K.; Agostinho, A. A.; Vasconcelos, L. P.; Miranda, Leandro E.

2012-01-01

The presence of aquatic macrophytes is a key factor in the selection of habitats by fish in floodplain lakes because these plants enhance the physical and biological complexities of aquatic habitats. The seasonal flood pulse may influence this interaction, but there is no information in the literature about the effects that flood events may have on macrophytes assemblages and its associated effects on fish assemblages. Thus, this article aimed to investigate whether species richness, evenness and similarities in fish assemblage composition differed between littoral areas vegetated with macrophytes and unvegetated areas, before and after a flood. We sampled three lakes in the floodplain of the upper Paraná River basin. Sampling was conducted before (December 2004 and January 2005) and after (early March, late March and May 2005) a flood event. Overall, species richness and evenness were higher in macrophytes-covered areas. Before the flood, the composition of fish assemblages was distinct when comparing vegetated and unvegetated areas. After the flood, the similarity in fish assemblage composition was higher, indicating a homogenization effect of floods for fish inhabiting littoral areas of floodplain lakes. After the flood, opportunistic species dominated the fish assemblages in aquatic macrophytes, apparently restructuring assemblages in the littoral, restarting a succession process. Thus, the observed homogenization effect of the flood could minimize biological interactions and could induce fish assemblages to begin a new process of structurization.

Landing Marine-derived Renewable Energy: Optimising Power Cable Routing in the Nearshore Environment

Science.gov (United States)

Turner, Rosalind, ,, Dr.; Keane, Tom; Mullins, Brian; Phipps, Peter

2010-05-01

estuary. Such difficulties include limited availability of superficial sediments for cable trenching and protection; where sediments were present there were indications that the sediments were either mobile sands, or difficult to trench glacial tills. Areas of the estuary feature steep side slopes and rocky outcrops, which also provide a challenge for cable installation and long-term protection. Difficult ground conditions were set against an aggressive meteo-oceanographic environment, tidal currents reached 5-7 knots on the ebb tide with reverse eddies around the landfalls coupled with an active wave climate. These conditions pose implications on the working time, installation vessels and methodology. The estuary is also a designated Special Area of Conservation for the protection of bottlenose dolphins, therefore, the cable installation methodology needed to consider ecological sensitivities. Additionally, an area near to the southern landfall has historically been an area of strategic significance and has a number of fortifications adding archaeological constraints for the cable route. The increasing need and importance of investigation and planning for submarine cable routes will be discussed alongside potential methods for installation in the aggressive nearshore environment, this paper will summarise findings and observations of working in a high energy environment, will consider options for installation and protection of cables, will discuss the key lessons learned and look at potential implications for offshore electricity generation.

Hyperspectral water quality retrieval model: taking Malaysia inshore sea area as an example

Science.gov (United States)

Cui, Tingwei; Zhang, Jie; Ma, Yi; Li, Jing; Lim, Boonleong; Roslinah, Samad

2007-11-01

Remote sensing technique provides the possibility of rapid and synchronous monitoring in a large area of the water quality, which is an important element for the aquatic ecosystem quality assessment of islands and coastal zones, especially for the nearshore and tourism sea area. Tioman Island of Malaysia is regarded as one of ten of the best islands in the world and attracts tourists from all over the world for its clear sea, beautiful seashore and charming scenery. In this paper, on the basis of in situ dataset in the study area, distribution discipline of water quality parameters is analyzed to find that phytoplankton pigment, rather than suspended sediment is the main water quality parameter in the study area; seawater there is clean but not very oligotrophic; seawater spectra contains distinct features. Then water quality hyperspectral retrieval models are developed based on in situ data to calculate the chlorophyll a concentration ([chl-a]), transparency (SD) with satisfactory performance. It's suggested that model precision should be validated further using more in-situ data.

Human impacts on large benthic foraminifers near a densely populated area of Majuro Atoll, Marshall Islands.

Science.gov (United States)

Osawa, Yoko; Fujita, Kazuhiko; Umezawa, Yu; Kayanne, Hajime; Ide, Yoichi; Nagaoka, Tatsutoshi; Miyajima, Toshihiro; Yamano, Hiroya

2010-08-01

Human impacts on sand-producing, large benthic foraminifers were investigated on ocean reef flats at the northeast Majuro Atoll, Marshall Islands, along a human population gradient. The densities of dominant foraminifers Calcarina and Amphistegina declined with distance from densely populated islands. Macrophyte composition on ocean reef flats differed between locations near sparsely or densely populated islands. Nutrient concentrations in reef-flat seawater and groundwater were high near or on densely populated islands. delta(15)N values in macroalgal tissues indicated that macroalgae in nearshore lagoons assimilate wastewater-derived nitrogen, whereas those on nearshore ocean reef flats assimilate nitrogen from other sources. These results suggest that increases in the human population result in high nutrient loading in groundwater and possibly into nearshore waters. High nutrient inputs into ambient seawater may have both direct and indirect negative effects on sand-producing foraminifers through habitat changes and/or the collapse of algal symbiosis. Copyright 2010 Elsevier Ltd. All rights reserved.

Trophic dynamics in marine nearshore systems of the Alaskan high arctic

International Nuclear Information System (INIS)

Dunton, K.H.

1985-01-01

This dissertation describes two ecological studies in the arctic Alaskan nearshore zone: the productivity and growth strategies of arctic kelp and the use of natural carbon isotope abundances to examine food web structure and energy flow in the marine ecosystem. Linear growth of the kelp, Laminaria solidungula is greatest in winter and early spring when nutrients are available for new tissue growth. Since over 90% of this growth occurs in complete darkness beneath a turbid ice canopy, the plant draws on stored food reserves and is in a carbon deficit during the ice covered period. Annual productivity of L. solidungula under these conditions is about 6 g C m -2 compared to about 10 g c m -2 if light penetrates the ice canopy. Carbon isotope abundances were used to assess food web structure and energy flow in the Boulder Patch, an isolated kelp bed community, and in the Alaskan Beaufort Sea fauna. Isotopic analyses of the resident fauna of the Boulder Patch revealed that kelp carbon contributes significantly to the diet of many benthic animals, including suspension feeders. Across the shelf of the Alaskan Beaufort Sea, a distinct gradient in the isotopic composition of marine zooplankton and benthic fauna was related to the intrusion of the Bering Sea water and upwelling in the eastern Beaufort Sea near Barter Island. The 13 C depletion in fauna of the eastern Beaufort Sea is presumed due to the cycling of 13 C depleted inorganic carbon into the euphotic zone

Efficient Calculation of Dewatered and Entrapped Areas Using Hydrodynamic Modeling and GIS

International Nuclear Information System (INIS)

Richmond, Marshall C.; Perkins, William A.

2009-01-01

River waters downstream of a hydroelectric project are often subject to rapidly changing discharge. Abrupt decreases in discharge can quickly dewater and expose some areas and isolate other areas from the main river channel, potentially stranding or entrapping fish, which often results in mortality. A methodology is described to estimate the areas dewatered or entrapped by a specific reduction in upstream discharge. A one-dimensional hydrodynamic model was used to simulate steady flows. Using flow simulation results from the model and a geographic information system (GIS), estimates of dewatered and entrapped areas were made for a wide discharge range. The methodology was applied to the Hanford Reach of the Columbia River in central Washington State. Results showed that a 280 m 3 /s discharge reduction affected the most area at discharges less than 3400 m 3 /s. At flows above 3400 m 3 /s, the affected area by a 280 m 3 /s discharge reduction (about 25 ha) was relatively constant. A 280 m 3 /s discharge reduction at lower flows affected about twice as much area. The methodology and resulting area estimates were, at the time of writing, being used to identify discharge regimes, and associated water surface elevations, that might be expected to minimize adverse impacts on juvenile fall chinook salmon (Oncorhynchus tshawytscha) that rear in the shallow near-shore areas in the Hanford Reach

Hubungan Kumpulan Mineral Berat pada Sedimen Pantai dan Lepas Pantai dengan Batuan Asal Darat di Perairan Teluk Pelabuhan Ratu, Jawa Barat

Directory of Open Access Journals (Sweden)

Deny Setiady

2014-06-01

Full Text Available DOI: 10.17014/ijog.v5i1.93Based on the depth contour, the sea bottom morphology in southern part of the researched area is very steep, while in the northern area it is sloped slightly. It shows that sedimentation process is from south to the north and continues to the west. It is supported by the current process in studied area. Rock slope stability of hilly morphology in the Cimandiri River area is related to weathering, erosion, and transportation process in coastal and nearshore areas. The presence of mineral in the studied area caused by those processes, was accumulated in the mouth of Cimandiri River, coastal, and nearshore areas. Those minerals were deposited in Cibelendung to Karangbeureum nearshore area by the longshore current. Magnetite and pyroxene minerals are dominant along the coastal and offshore areas of Pelabuhan Ratu Bay. The presence of augite and diopside shows that the source rock is basic igneous rocks (basalt, while the presence of hornblende and biotite minerals tend to indicate that the source rock is intermediate igneous rocks (andesite.

Establishment of two invasive crustaceans (Copepoda: Harpacticoida) on the nearshore sands of Lake Michigan

Science.gov (United States)

Horvath, Thomas G.; Whitman, Richard L.; Last, Laurel L.

2001-01-01

Benthic copepods (Copepoda: Harpacticoida) in the nearshore sediments of southern Lake Michigan appear to be dominated by two new invasive species. We report the first occurrence in North America of Schizopera borutzkyi Montschenko, a native to the Danube River delta, and Heteropsyllus nr. nunni, likely a new species that is morphologically similar to the marine species Heteropsyllus nunni and represents the first occurrence of this genus in freshwater. Schizopera borutzkyi is a euryhaline species occurring in shallow sands in its native habitat and in deeper sands (6-15 m) in southern Lake Michigan. Based on the absence of these species from previous studies, we suggest that they are recent introductions. Heteropsyllus nr. nunni dominated (55-100%) the harpacticoid abundance to depths of 9 m, but S. borutzkyi comprised 75% of the harpacticoid abundance at 15 m. Native harpacticoids were always greatly outnumbered by invasive harpacticoids in our samples, which suggests that the natives are being replaced rapidly or that the invasive species are finding unused resources. The ecological implications of these introductions are not known, but these invasions may represent continued 'invasional meltdown' in Lake Michigan.

Marine depth use of sea trout Salmo trutta in fjord areas of central Norway

DEFF Research Database (Denmark)

Eldøy, S. H.; Davidsen, J. G.; Thorstad, E. B.

2017-01-01

(day v. night), season, seawater temperature and the body length at the time of tagging. Mean swimming depth during May-September was 1·7 m (individual means ranged from 0·4 to 6·4 m). Hence, S. trutta were generally surface oriented, but performed dives down to 24 m. Mean swimming depth in May...... movements. During summer, S. trutta residing in near-shore habitat progressively moved deeper over the period May (mean 1·1 m) to August (mean 4·0 m) and then reoccupied shallower areas (mean 2·3 m) during September. In winter (November and February), individuals residing in the innermost part of the fjords...

Mercury Sources and Cycling in the Great Lakes: Dramatic Changes Resulting from Altered Atmospheric Loads and the Near-Shore Shunt

Science.gov (United States)

Krabbenhoft, D. P.; DeWild, J. F.; Maglio, M. M.; Tate, M. T.; Ogorek, J. M.; Hurley, J. P.; Lepak, R.

2013-12-01

there have been large declines in surface water total Hg concentrations (50-75%) across the Great Lakes since about 2000, an observation in agreement with concurrent declines in atmospheric deposition. In addition to a decline in inputs, we hypothesize that appreciable increases in volatilization of gaseous Hg have occurred. Mercury volatilization is directly related to water clarity (via the photo-reduction process), which has increased substantially in the Great Lakes since the invasion of zebra mussels and quagga mussels. Finally, although substantial declines in total aqueous Hg levels are apparent, fish mercury levels over the same time period appear to be relatively steady, and in some locations increasing. We submit this apparent discordance is also the outcome of the invasive mussels, which have caused near-shore eutrophication and off-shore oligotrophication commonly referred to as the near-shore shunt. Initial sampling by this project has revealed that these eutrophied zones are markedly enriched in MeHg. Therefore, it appears that while the open water regions of the Great Lakes appear to have experienced significant aqueous Hg declines, fish Hg levels may be responding to a new site of methylation in the near-shore zone.

Argan woodlands in South Morocco as an area of conflict between degradation and sustainable land use

Science.gov (United States)

Kirchhoff, Mario; Kagermeier, Andreas; Ries, Johannes B.

2016-04-01

The Argan woodlands are endemic for South Morocco and prone to degradation through expanding and intensifying agriculture and overgrazing. Unvegetated areas extend further due to degradation of soil and vegetation. Here infiltration is less than on vegetated areas, while runoff and soil erosion increase. The sale of the highly valuable oil, gained from the seeds of the argan tree, can be seen as an economic alternative for the region and a chance of survival for the argan woodlands. With the introduction of women's cooperatives for the production and sale of the oil, the Gesellschaft für Technische Zusammenarbeit (GTZ, Association for Technical Cooperation) hoped to halt argan degradation from 1995 to 2002. The effects of this approach shall be studied in a proposed DFG-project. The erosion gradient between soils under canopy cover and intertree areas in varying stages of degradation will be at the center of the analysis. Insight into onsite and offsite degradation shall be gained through the measurement of runoff and erosion rates, which lead to rill and gully erosion downslope. Measurements of soil chemical and physical properties might also help indicate when an argan woodland can be classified as natural. Furthermore to be studied are the effects of the new found value of the Argan woodlands among the local population with focus on regional tourism and a possible reduction of grazing pressure. Sustainable soil management in combination with the needs of the local population is essential for a sustainable land use in the region.

Coastal wind study based on Sentinel-1 and ground-based scanning lidar

DEFF Research Database (Denmark)

Hasager, Charlotte Bay; Badger, Merete; Pena Diaz, Alfredo

Winds in the coastal zone have importance for near-shore wind farm planning. Recently the Danish Energy Agency gave new options for placing offshore wind farms much closer to the coastlines than previously. The new tender areas are located from 3 to 8 km from the coast. Ground-based scanning lidar...... located on land can partly cover this area out to around 15 km. In order to improve wind farm planning for near-shore coastal areas, the project‘Reducing the Uncertainty of Near-shore Energy estimates from meso- and micro-scale wind models’ (RUNE) is established. The measurement campaign starts October....... The various observation types have advantages and limitations; one advantage of both the Sentinel-1 and the scanning lidar is that they both observe wind fields covering a large area and so can be combined for studying the spatial variability of winds. Sentinel-1 are being processed near-real-time at DTU Wind...

Density, size structure, shell orientation and epibiontic colonization of the fan mussel Pinna nobilis L. 1758 (Mollusca: Bivalvia in three contrasting habitats in an estuarine area of Sardinia (W Mediterranean

Directory of Open Access Journals (Sweden)

Piero Addis

2009-03-01

Full Text Available We investigated the spatial distribution, size structure, shell orientation and valve colonization by epibionts of the endangered Mediterranean bivalve Pinna nobilis in three continuous but different habitats in the Gulf of Oristano (Sardinia, western Mediterranean. The sampling stations chosen were: an estuarine area (E of coastal salt-marshes characterized by unvegetated sea-bottoms; and two areas in a seagrass meadow characterized by an extensive Posidonia oceanica meadow (Mw and patched mixed meadows of P. oceanica and Cymodocea nodosa (Me. We found significant differences in mean densities among stations and the highest value was found in the estuarine area. Shell orientation showed that there was uniform circular distribution of specimens in the Mw station and a unimodal distribution in the Me and E stations, where specimens were set at 0°N and 10°NNE, which is a pattern related to sea drift. Shell epibiosis displayed differences between habitats. The highest valve colonization was in the estuary, with filamentous dark algae and Ostrea edulis reaching almost 90 percent of shell coverage. This study provides new information on habitat preferences and data for assessing local populations of P. nobilis that is useful for its conservation and improving the knowledge of its ecology.

Near-shore Antarctic pH variability has implications for the design of ocean acidification experiments

Science.gov (United States)

Kapsenberg, Lydia; Kelley, Amanda L.; Shaw, Emily C.; Martz, Todd R.; Hofmann, Gretchen E.

2015-01-01

Understanding how declining seawater pH caused by anthropogenic carbon emissions, or ocean acidification, impacts Southern Ocean biota is limited by a paucity of pH time-series. Here, we present the first high-frequency in-situ pH time-series in near-shore Antarctica from spring to winter under annual sea ice. Observations from autonomous pH sensors revealed a seasonal increase of 0.3 pH units. The summer season was marked by an increase in temporal pH variability relative to spring and early winter, matching coastal pH variability observed at lower latitudes. Using our data, simulations of ocean acidification show a future period of deleterious wintertime pH levels potentially expanding to 7–11 months annually by 2100. Given the presence of (sub)seasonal pH variability, Antarctica marine species have an existing physiological tolerance of temporal pH change that may influence adaptation to future acidification. Yet, pH-induced ecosystem changes remain difficult to characterize in the absence of sufficient physiological data on present-day tolerances. It is therefore essential to incorporate natural and projected temporal pH variability in the design of experiments intended to study ocean acidification biology.

Invasive ecosystem engineer selects for different phenotypes of an associated native species.

Science.gov (United States)

Wright, Jeffrey T; Gribben, Paul E; Byers, James E; Monro, Keyne

2012-06-01

Invasive habitat-forming ecosystem engineers modify the abiotic environment and thus represent a major perturbation to many ecosystems. Because native species often persist in these invaded habitats but have no shared history with the ecosystem engineer, the engineer may impose novel selective pressure on native species. In this study, we used a phenotypic selection framework to determine whether an invasive habitat-forming ecosystem engineer (the seaweed Caulerpa taxifolia) selects for different phenotypes of a common co-occurring native species (the bivalve Anadara trapezia). Compared to unvegetated habitat, Caulerpa habitat has lower water flow, lower dissolved oxygen, and sediments are more silty and anoxic. We determined the performance consequences of variation in key functional traits that may be affected by these abiotic changes (shell morphology, gill mass, and palp mass) for Anadara transplanted into Caulerpa and unvegetated habitat. Both linear and nonlinear performance gradients in Anadara differed between habitats, and these gradients were stronger in Caulerpa compared to unvegetated sediment. Moreover, in Caulerpa alternate phenotypes performed well, and these phenotypes were different from the dominant phenotype in unvegetated sediment. By demonstrating that phenotype-performance gradients differ between habitats, we have highlighted a role for Caulerpa as an agent of selection on native species.

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

Science.gov (United States)

Ginzburg, Boris; Cohen, Tsuriel Ram; Zafrir, Hovav; Alimi, Roger; Salomonski, Nizan; Sharvit, Jacob

2007-01-01

The purpose of this paper is to present a system developed for detection and accurate mapping of ferro-metallic objects buried below the seabed in shallow waters. The system comprises a precise magnetic gradiometer and navigation subsystem, both installed on a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition we present the results of a marine survey of a near-shore area in the vicinity of Atlit, a town situated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primary purpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960. A magnetic map of the survey area (3.5 km2 on a 0.5 m grid) was created revealing the anomalies at sub-meter accuracy. For each investigated target location a corresponding ferro-metallic item was dug out, one of which turned to be very similar to a part of the crashed airplane. The accuracy of location was confirmed by matching the position of the actual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m. PMID:28903191

High Resolution Marine Magnetic Survey of Shallow Water Littoral Area

Directory of Open Access Journals (Sweden)

Jacob Sharvit

2007-09-01

Full Text Available The purpose of this paper is to present a system developed for detection andaccurate mapping of ferro-metallic objects buried below the seabed in shallow waters. Thesystem comprises a precise magnetic gradiometer and navigation subsystem, both installedon a non-magnetic catamaran towed by a low-magnetic interfering boat. In addition wepresent the results of a marine survey of a near-shore area in the vicinity of Atlit, a townsituated on the Mediterranean coast of Israel, about 15 km south of Haifa. The primarypurpose of the survey was to search for a Harvard airplane that crashed into the sea in 1960.A magnetic map of the survey area (3.5 km2 on a 0.5 m grid was created revealing theanomalies at sub-meter accuracy. For each investigated target location a correspondingferro-metallic item was dug out, one of which turned to be very similar to a part of thecrashed airplane. The accuracy of location was confirmed by matching the position of theactual dug artifacts with the magnetic map within a range of ± 1 m, in a water depth of 9 m.

Quantifying the effects of European beach grass on aeolian sand transport over the last century: Bodega Marine Reserve, California

Science.gov (United States)

Cesmat, R.; Werner, S.; Smith, M. E.; Riedel, T.; Best, R.; Olyarnik, S.

2012-12-01

Introduction of European beach grass (Ammophila arenaria) to coastal dune systems of western North America induced significant changes to the transport and storage of sediment, and consequently the nesting habitat of the western snowy plover (Charadrius alexandrinus nivosus). At the Bodega Marine Reserve and Sonoma Coast State Park, Ammophila was introduced within the ~0.5 km2 dune area in the 1920's to limit the flux of sand through Bodega Harbor and agricultural land. To assess the potential impact of restoration efforts (Ammophila removal) on aeolian sediment flux, we measured sediment flux as a function of wind speeds and ground cover, and used these measurements to parameterize a spatial model for historical sand deposition Fine- to coarse-grained lithic to sub-lithic sand is delivered to the Bodega dune system from Salmon Creek beach, the down-shore terminus of a littoral system fed by the 3846 km2 Russian River catchment, several small (Gaffney ridge) at the edge of the planted region. An average accumulation rate of ~4,000 m3/yr is indicated within the study swath by the preserved sediment volumes. Within the modern dune system, unvegetated areas exhibit 2-3 meter wavelength, ~1/2 meter amplitude mega-ripples, and the uppermost 2-10 cm consists of coarse-sand to granule-sized armor layer. In contrast, grain-sizes in vegetated areas are largely vertically homogenous. Open areas are typically 2-8 meters lower than adjacent vegetated areas, and show evidence for net lowering of the land surface (i.e., exposed fence posts, roots). Conversely, vegetated areas appear prone to sediment accumulation, particularly downwind of unvegetated areas. We measured sand transport using 0.5 m high traps deployed at 18 sites throughout the dune field, and used a linear mixed effects model to predict transport rate as a function of wind and ground cover class, taking into account random effects of sampling date and repeated measurements at each site. The analysis indicates up

Phytopathology Prediction in Dry Soil Using Artificial Neural Networks Modeling

OpenAIRE

F. Allag; S. Bouharati; M. Belmahdi; R. Zegadi

2014-01-01

The rapid expansion of deserts in recent decades as a result of human actions combined with climatic changes has highlighted the necessity to understand biological processes in arid environments. Whereas physical processes and the biology of flora and fauna have been relatively well studied in marginally used arid areas, knowledge of desert soil micro-organisms remains fragmentary. The objective of this study is to conduct a diversity analysis of bacterial communities in unvegetated arid soil...

Population structure of Cladophora-borne Escherichia coli in nearshore water of Lake Michigan.

Science.gov (United States)

Byappanahalli, Muruleedhara N; Whitman, Richard L; Shively, Dawn A; Ferguson, John; Ishii, Satoshi; Sadowsky, Michael J

2007-08-01

We previously reported that the macrophytic green alga Cladophora harbors high densities (up to 10(6) colony-forming units/g dry weight) of the fecal indicator bacteria, Escherichia coli and enterococci, in shoreline waters of Lake Michigan. However, the population structure and genetic relatedness of Cladophora-borne indicator bacteria remain poorly understood. In this study, 835 E. coli isolates were collected from Cladophora tufts (mats) growing on rocks from a breakwater located within the Indiana Dunes National Lakeshore in northwest Indiana. The horizontal fluorophore enhanced rep-PCR (HFERP) DNA fingerprinting technique was used to determine the genetic relatedness of the isolates to each other and to those in a library of E. coli DNA fingerprints. While the E. coli isolates from Cladophora showed a high degree of genetic relatedness (92% similarity), in most cases, however, the isolates were genetically distinct. The Shannon diversity index for the population was very high (5.39). Both spatial and temporal influences contributed to the genetic diversity. There was a strong association of isolate genotypes by location (79% and 80% for lake- and ditch-side samplings, respectively), and isolates collected from 2002 were distinctly different from those obtained in 2003. Cladophora-borne E. coli isolates represented a unique group, which was distinct from other E. coli isolates in the DNA fingerprint library tested. Taken together, these results indicate that E. coli strains associated with Cladophora may be a recurring source of indicator bacteria to the nearshore beach.

Oil in nearshore subtidal sediments of Saudi Arabia from the Gulf War spill

International Nuclear Information System (INIS)

Michel, J.; Hayes, M.O.; Keenan, R.S.; Jensen, J.R.; Narumalani, S.

1993-01-01

Detailed sedimentological and dynamic-process studies of the shallow, subtidal habitats of Dawhats ad Dafi and al Mussallamiyah and the bays at Tanaqib on the Saudi Arabian coast were carried out one year after the Gulf War oil spill. These studies were part of Leg II of the NOAA ship Mt. Mitchell cruise. Satellite imagery and space shuttle photography were used extensively to develop detailed study plans. Work accomplished during the study included deployment of three current meters, a tide gauge, and suspended sediment traps (at seven locations). Bathymetric surveys were conducted along 14 transects, and 197 bottom observation dives were carried out. More than 170 bottom sediment samples were collected for chemical and/or textural analysis. Sediment hydrocarbon screening by HPLC fluorescence was conducted on board to verify and refine the sampling plan. The results to date show no evidence of large-scale sinking of oil as a result of the spill. Subtidal oil, as sparse tar balls, was visually observed by divers at three locations, all of which were associated with the erosion of oiled sand from outer beaches. On-board chemical results showed that subtidal sediments have been contaminated at levels ranging from 20 to 2,000 mg petroleum hydrocarbons/kg, with the highest contamination up in the sheltered, muddy basins. However, the oil initially stranded in the intertidal zone does not appear to be accumulating in the nearshore subtidal region in significant quantities one year later

Tsunami-Induced Nearshore Hydrodynamic Modeling using a 3D VOF Method: A Gulf of Mexico Case Study

Science.gov (United States)

Kian, R.; Horrillo, J. J.; Fang, N. Z.

2017-12-01

Long-term morphology changes can be interrupted by extreme events such as hurricanes and tsunamis. In particular, the impact of tsunamis on coastal erosion and accretion patterns is presently not well understood. In order to understand the sediment movement during coastal tsunami impact a numerical sediment transport model is added to a 3D VOF model. This model allows for spatially varying bottom sediment characteristics and entails functions for entrainment, bedload, and suspended load transport. As a case study, a Gulf of Mexico (GOM) coastal study site is selected to investigate the effect of a landslide-tsunami on the coastal morphology. The GOM is recognized as a vast and productive body of water with great ecologic and economic value. The morphodynamic response of the nearshore environment to the tsunami hydrodynamic forcing is influenced by many factors including bathymetry, topography, tsunami wave and current magnitude, and the characteristics of the local bottom substrate. The 3D model addition can account for all these factors. Finally, necessary strategies for reduction of the potential tsunami impact and management of the morphological changes are discussed.

Modeling nearshore dispersal of river-derived multi-class suspended sediments and radionuclides during a flood event around the mouth of Niida River, Fukushima, Japan

Science.gov (United States)

Uchiyama, Y.; Yamanishi, T.; Iwasaki, T.; Shimizu, Y.; Tsumune, D.; Misumi, K.; Onda, Y.

2016-12-01

A quadruple nested synoptic oceanic downscale modeling based on ROMS was carried out to investigate hydrodynamics, multi-class non-cohesive sediment transport and associated dispersal of suspended radionuclides (cesium-137; 137Cs) originated from the nuclear accident occurred at the Fukushima Dai-ichi Power Plant in March 2011. The innermost model has horizontal grid resolution of 50 m to marginally resolve the topography around the river mouth including the surf zone. The model is forced by the JCOPE2 oceanic reanalysis as the outermost boundary conditions, the GPV-MSM atmospheric reanalysis, and an in-house SWAN spectral wave hindcast embedded in the operational GPV-CWM wave reanalysis. A particular attention is paid to nearshore behaviors and inventory of the nuclides attached to terrestrial minerals with grain sizes ranging from 5 to 79 micrometers that have been occasionally discharged out to the coastal ocean through hydrological processes within the river basin even after several years since the accident. We examine oceanic dispersal of sediment and suspended 137Cs influxes from Niida River, Fukushima, evaluated with the iRIC-Nays2DH river model. Our focus is on the first flood event in late May of 2011 after the accident. Alongshore asymmetry in transport of suspended sediments and 137Cs is exhibited, comprising storm-driven southward transport confined in the shallow area due to shoreward Ekman transport associated with strong northerly wind, followed by northwestward wide-spread transport under mild southerly wind condition. About 70 % of the Niida River-derived suspended 137Cs remains near the mouth for 20 days after the flood event. Nevertheless, our model results as well as an observation suggest that the area is dominated by erosion as for high bed shear stress all the time, thus suspended radionuclides are redistributed to dissipate away in long term.

An upwelling-induced retention area off Senegal: A mechanism to ...

African Journals Online (AJOL)

Chlorophyll distribution peaks nearshore. This unique surface structure is interpreted as the result of a “double cell” structure in the upwelling vertical circulation: a first cell located at the shelf break, the main upwelling cell that brings cold and nutrient-rich subsurface water to the surface, and a second cell located inshore of ...

Characteristics and parameters of bed-load movement for multi-bar near-shore zone on the base of tracer field experiments

International Nuclear Information System (INIS)

Wierzchnicki, R.

1997-01-01

The radiotracer method for field investigation of marine bed sediments in Baltic Sea near-shore zone has been elaborated and successfully used. The artificial sand made of special glass containing Ir-192 and quartz like density has been used as a tracer. The field experiments have been carried out at Coastal Station of the Institute of Hydroengineering in Lubiatowo. The tracer movement has been observed at different weather and wave conditions. On the base of obtained data the next characteristics and parameters of sand transport have been defined and discussed: critical velocities of sand grains; sediment velocities versus the long shore current; thickness of the layer transported; intensity of the transport. For the purpose of coastal engineering practice the global transport intensity in the multi bar-coastal zone conditions has been determined as a function of main parameters describing breaking waves (height and propagation angle)

Toxicity of dispersant application: Biomarkers responses in gills of juvenile golden grey mullet (Liza aurata)

International Nuclear Information System (INIS)

Milinkovitch, Thomas; Godefroy, Joachim; Theron, Michael; Thomas-Guyon, Helene

2011-01-01

Dispersant use in nearshore areas is likely to increase the exposure of aquatic organisms to petroleum. To measure the toxicity of this controversial response technique, golden grey mullets (Liza aurata) were exposed to mechanically dispersed oil, chemically dispersed oil, dispersant alone in seawater, water-soluble fraction of oil and to seawater as a control treatment. Several biomarkers were assessed in the gills (enzymatic antioxidant activities, glutathione content, lipid peroxidation) and in the gallbladder (polycylic aromatic hydrocarbons metabolites). The significant differences between chemically dispersed oil and water soluble fraction of oil highlight the environmental risk to disperse an oil slick when containment and recovery can be conducted. The lack of significance between chemically and mechanically dispersed oil suggests that dispersant application is no more toxic than the natural dispersion of the oil slick. The results of this study are of interest in order to establish dispersant use policies in nearshore areas. - Highlights: → This study simulates and evaluates the toxicity of dispersant use in nearshore area. → Dispersant use toxicity is assessed through biomarkers measurement in a fish species. → Chemical dispersion of an oil slick increases the petroleum toxicity. → Dispersant use does not enhance the toxicity of a mechanically dispersed oil slick. → This work leads to conclusions concerning dispersant use policies in nearshore area. - When the meteorological conditions induce the dispersion of the oil slick (e.g. wave), the application of dispersant does not increase the toxicity of petroleum.

The presence and near-shore transport of human fecal pollution in Lake Michigan beaches

Science.gov (United States)

Molloy, S.L.; Liu, L.B.; Phanikumar, M.S.; Jenkins, T.M.; Wong, M.V.; Rose, J.B.; Whitman, R.L.; Shively, D.A.; Nevers, M.B.

2005-01-01

The Great Lakes are a source of water for municipal, agricultural and industrial use, and support significant recreation, commercial and sport fishing industries. Every year millions of people visit the 500 plus recreational beaches in the Great Lakes. An increasing public health risk has been suggested with increased evidence of fecal contamination at the shoreline. To investigate the transport and fate of fecal pollution at Great Lakes beaches and the health risk associated with swimming at these beaches, the near-shore waters of Mt Baldy Beach, Lake Michigan and Trail Creek, a tributary discharging into the lake were examined for fecal pollution indicators. A model of surf zone hydrodynamics coupled with a transport model with first-order inactivation of pollutant was used to understand the relative importance of different processes operating in the surf zone (e.g. physical versus biological processes). The Enterococcus human fecal pollution marker, which targets a putative virulence factor, the enterococcal surface protein (esp) in Enterococcus faecium, was detected in 2/28 samples (7%) from the tributaries draining into Lake Michigan and in 6/30 samples (20%) from Lake Michigan beaches. Preliminary analysis suggests that the majority of fecal indicator bactateria variation and water quality changes at the beaches can be explained by inputs from the influential stream and hydrometeorological conditions. Using modeling methods to predict impaired water quality may help reduce potential health threats to recreational visitors.

Effect of soil organic matter on antimony bioavailability after the remediation process.

Science.gov (United States)

Nakamaru, Yasuo Mitsui; Martín Peinado, Francisco José

2017-09-01

We evaluated the long-term (18 year) and short-term (4 weeks) changes of Sb in contaminated soil with SOM increase under remediation process. In the Aznalcóllar mine accident (1998) contaminated area, the remediation measurement implemented the Guadiamar Green Corridor, where residual pollution is still detected. Soils of the re-vegetated area (O2) with high pH and high SOM content, moderately re-vegetated area (O1) and unvegetated area (C) were sampled. Soil pH, CEC, SOM amount and soil Sb forms were evaluated. Soil Sb was measured as total, soluble, exchangeable, EDTA extractable, acid oxalate extractable, and pyro-phosphate extractable fractions. Further, the short-term effect of artificial organic matter addition was also evaluated with incubation study by adding compost to the sampled soil from C, O1 and O2 areas. After 4 weeks of incubation, soil chemical properties and Sb forms were evaluated. In re-vegetated area (O2), soil total Sb was two times lower than in unvegetated area (C); however, soluble, exchangeable, and EDTA extractable Sb were 2-8 times higher. The mobile/bioavailable Sb increase was also observed after 4 weeks of incubation with the addition of compost. Soluble, exchangeable, and EDTA extractable Sb was increased 2-4 times by compost addition. By the linear regression analysis, the significantly related factors for soluble, exchangeable, and EDTA extractable Sb values were pH, CEC, and SOM, respectively. Soluble Sb increase was mainly related to pH rise. Exchangeable Sb should be bound by SOM-metal complex and increased with CEC. EDTA extractable fraction should be increased with increase of SOM as SOM-Fe associated Sb complex. From these results, it was shown that increase of SOM under natural conditions or application of organic amendment under remediation process should increase availability of Sb to plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Water Quality and Environmental Flow Management in Rapidly Urbanizing Shenzhen Estuary Area, China

Science.gov (United States)

Qin, H.; Su, Q.

2011-12-01

Shenzhen estuary is located in a rapidly urbanizing coastal region of Southeast China, and forms the administrative border between mainland China and Hong Kong. It receives the waters of the Shenzhen River, where it enters the Deep Bay. The estuary has great ecological importance with the internationally recognized mangrove wetlands, which provides a habitat for some rare and endangered waterfowl and migratory birds.Water quality in the esturay has deteriorated not only due to increasing wastewater discharges from domestic and industrial sources, but also as a consequence of decreasing base environmental flow during rapid urbanization in the Shenzhen River catchment since 1980s. Measures to improve water quality of the estuary include not only reducing pollutant inputs by intercepting wastewater, but also increasing environmental flow by reusing reclaimed wastewater or withdrawing nearshore seawater into the river. However, salinity alternation due to flow increase is deemed to have impacts on the mangrove wetland ecosystem. In this paper, Environmental Fluid Dynamics Code (EFDC) is used to simulate hydrodynamics, salinity, and water quality condition in the Shenzhen estuary. After calibration and validation, the model is used to evaluate effects of various control measures on water quality improvement and salinity alteration in the estuary. The results indicate that implementing different measures independently does not reach the goals of water quality improvement; furthermore, increasing environmental flow by importing nearshore seawater may greatly increase the salinity in the Shenzhen River, destroy the fresh ecosystem of the river and have non-negligible impacts on the mangrove wetland ecosystem. Based on the effectiveness and impacts of the measures, an integrated measure, which combine pollutant loads reduction and environmental flow increase by reusing reclaimed wastewater, is proposed to achieve water environmental sustainability in the study area.

Pb-210 and Pu-239,240 in nearshore Gulf of Mexico sediments

International Nuclear Information System (INIS)

Rotter, R.J.

1985-05-01

Pb-210, Ra-226, and Pu-239,240 activities were measured in nearshore Gulf of Mexico sediments. Sediment cores were collected from the Mississippi delta, and the western Gulf of Mexico shelf. Mississippi delta cores which exhibit significantly higher sedimentation rates show larger inventories of Pb-210. The measured Pu levels from the western shelf are lower than from the delta at comparable depths. In three of the western shelf cores, the observed Pu inventory is considerably less than predicted from atmospheric flux. Therefore, Pu is not being removed to the sediment, or is being released following deposition. A key difference between these isotopes is that Pu exists in a less particle-reactive state. The ratio of excess Pb-210 to Pu levels increases with water depth in the delta and the western shelf. Water depth acts as an integrator of depth-sensitive processes. Pu scavenging is more sensitive to these processes. A sub-surface Pu maximum has been observed. Excess Pb-210 and Pu levels correlate well with sedimentation rates. This suggests that particle flux is important in removal of Pb-210 and Pu to the sediment. The flux of Mn out of the sediment is correlated with inventory data, suggesting that redox cycling of Mn may play a role in increasing Pb-210 and Pu sediment inventories. It is unclear whether the effects of increased sedimentation rates and increased Mn fluxes can be evaluated independently. Mixing of surface sediment correlates with inventory data. Increased sediment mixing allows for additional scavenging of Pb-210 and Pu from overlying waters. Mixing of sediment at depths below the mixed surface layer may play a role in increasing sediment inventories of Pb-210 and Pu

Effects of Changing Weather, Oceanographic Conditions, and Land Uses on Spatio-Temporal Variation of Sedimentation Dynamics along Near-Shore Coral Reefs

Directory of Open Access Journals (Sweden)

Abimarie Otaño-Cruz

2017-08-01

Full Text Available Sedimentation is a critical threat to coral reefs worldwide. Major land use alteration at steep, highly erodible semi-arid islands accelerates the potential of soil erosion, runoff, and sedimentation stress to nearshore coral reefs during extreme rainfall events. The goal of this study was to assess spatio-temporal variation of sedimentation dynamics across nearshore coral reefs as a function of land use patterns, weather and oceanographic dynamics, to identify marine ecosystem conservation strategies. Sediment was collected at a distance gradient from shore at Bahia Tamarindo (BTA and Punta Soldado (PSO coral reefs at Culebra Island, Puerto Rico. Sediment texture and composition were analyzed by dry sieving and loss-on-ignition techniques, and were contrasted with environmental variables for the research period (February 2014 to April 2015. Rainfall and oceanographic data were analyzed to address their potential role on affecting sediment distribution with BEST BIO-ENV, RELATE correlation, and linear regression analysis. A significant difference in sedimentation rate was observed by time and distance from shore (PERMANOVA, p < 0.0100, mostly attributed to higher sediment exposure at reef zones closer to shore due to strong relationships with coastal runoff. Sedimentation rate positively correlated with strong rainfall events (Rho = 0.301, p = 0.0400 associated with storms and rainfall intensity exceeding 15 mm/h. At BTA, sediment deposited were mostly composed of sand, suggesting a potential influence of resuspension produced by waves and swells. In contrast, PSO sediments were mostly composed of silt-clay and terrigenous material, mainly attributed to a deforestation event that occurred at adjacent steep sub-watershed during the study period. Spatial and temporal variation of sedimentation pulses and terrigenous sediment input implies that coral reefs exposure to sediment stress is determined by local land use patterns, weather, and

Nearshore Processes, Currents and Directional Wave Spectra Monitoring Using Coherent and Non-coherent Imaging Radars

Science.gov (United States)

Trizna, D.; Hathaway, K.

2007-05-01

Two new radar systems have been developed for real-time measurement of near-shore processes, and results are presented for measurements of ocean wave spectra, near-shore sand bar structure, and ocean currents. The first is a non-coherent radar based on a modified version of the Sitex radar family, with a data acquisition system designed around an ISR digital receiver card. The card operates in a PC computer with inputs from a Sitex radar modified for extraction of analogue signals for digitization. Using a 9' antenna and 25 kW transmit power system, data were collected during 2007 at the U.S. Army Corps of Engineers Field Research Facility (FRF), Duck, NC during winter and spring of 2007. The directional wave spectrum measurements made are based on using a sequence of 64 to 640 antenna rotations to form a snapshot series of radar images of propagating waves. A square window is extracted from each image, typically 64 x 64 pixels at 3-m resolution. Then ten sets of 64 windows are submitted to a three-dimensional Fast Fourier Transform process to generate radar image spectra in the frequency-wavenumber space. The relation between the radar image spectral intensity and wave spectral intensity derived from the FRF pressure gauge array was used for a test set of data, in order to establish a modulation transfer function (MTF) for each frequency component. For 640 rotations, 10 of such spectra are averaged for improved statistics. The wave spectrum so generated was compared for extended data sets beyond those used to establish the MTF, and those results are presented here. Some differences between the radar and pressure sensor data that are observed are found to be due to the influence of the wind field, as the radar echo image weakens for light winds. A model is developed to account for such an effect to improve the radar estimate of the directional wave spectrum. The radar ocean wave imagery is severely influenced only by extremely heavy rain-fall rates, so that

Variation in Spring Nearshore Resident Fish Species Composition and Life Histories in the Lower San Joaquin Watershed and Delta

Directory of Open Access Journals (Sweden)

Larry R. Brown

2006-09-01

Full Text Available Providing freshwater to human populations while protecting or rehabilitating ecosystem health is a significant challenge to water resource managers and requires accurate knowledge of aquatic resources. Previous studies of fish assemblages in the San Francisco Estuary and watershed have focused on specific habitat types, water bodies, or geographic subregions. In this study, we use seining data from two monitoring programs to provide an integrated view of spring nearshore resident fish species composition and life history characteristics in five regions: the San Joaquin River, the upper Sacramento River, the lower Sacramento River, the northern Sacramento-San Joaquin Delta (North Delta, and the Interior Delta. Data for the period March-May from 1994 to 2002, showed that spring species composition of the San Joaquin River was very different from the other four regions. Total catch in the San Joaquin River was dominated by small, short-lived batch spawning alien species (93%, particularly red shiner Cyprinella lutrensis (>75% of total catch. The upper and lower Sacramento River were very similar in species composition and life history characteristics and less dominated by alien fish (

Uranium and base metal dispersion studies in the Maquire Lake area, Saskatchewan

International Nuclear Information System (INIS)

Sopuck, V.J.; Lehto, D.A.W.; Alley, D.W.

1980-03-01

The objective of this study was to study uranium and base metal dispersion in various sample media occurring in the Maguire Lake area of Saskatchewan: bedrock, overburden, lake water, and lake sediments. Factors controlling partitioning of metals among various sample media were investigated, and lake sediment data were interpreted in terms of the factors to determine the significance of lake sediment data in indicating local mineralization. The association between organic matter contents and metal contents was found to vary between lake-center and nearshore sediments. Nickel, cobalt and zinc in lake sediments are strongly controlled by hydroxide precipitation and are less dependent on bedrock type. The concentration of Fe in center-lake sediments appears to reflect only the physicochemical parameters in the lake. Uranium and copper are strongly controlled by and preferentially concentrated in the organic matter; however, in center-lake sediments with >12 percent organic matter, U and Cu strongly reflect rock type

Synthesis study of an erosion hot spot, Ocean Beach, California

Science.gov (United States)

Barnard, Patrick L.; Hansen, Jeff E.; Erikson, Li H.

2012-01-01

A synthesis of multiple coastal morphodynamic research efforts is presented to identify the processes responsible for persistent erosion along a 1-km segment of 7-km-long Ocean Beach in San Francisco, California. The beach is situated adjacent to a major tidal inlet and in the shadow of the ebb-tidal delta at the mouth of San Francisco Bay. Ocean Beach is exposed to a high-energy wave climate and significant alongshore variability in forcing introduced by varying nearshore bathymetry, tidal forcing, and beach morphology (e.g., beach variably backed by seawall, dunes, and bluffs). In addition, significant regional anthropogenic factors have influenced sediment supply and tidal current strength. A variety of techniques were employed to investigate the erosion at Ocean Beach, including historical shoreline and bathymetric analysis, monthly beach topographic surveys, nearshore and regional bathymetric surveys, beach and nearshore grain size analysis, two surf-zone hydrodynamic experiments, four sets of nearshore wave and current experiments, and several numerical modeling approaches. Here, we synthesize the results of 7 years of data collection to lay out the causes of persistent erosion, demonstrating the effectiveness of integrating an array of data sets covering a huge range of spatial scales. The key findings are as follows: anthropogenic influences have reduced sediment supply from San Francisco Bay, leading to pervasive contraction (i.e., both volume and area loss) of the ebb-tidal delta, which in turn reduced the regional grain size and modified wave focusing patterns along Ocean Beach, altering nearshore circulation and sediment transport patterns. In addition, scour associated with an exposed sewage outfall pipe causes a local depression in wave heights, significantly modifying nearshore circulation patterns that have been shown through modeling to be key drivers of persistent erosion in that area.

Harmful algal blooms (HABs), dissolved organic matter (DOM), and planktonic microbial community dynamics at a near-shore and a harbour station influenced by upwelling (SW Iberian Peninsula)

Science.gov (United States)

Loureiro, Sofia; Reñé, Albert; Garcés, Esther; Camp, Jordi; Vaqué, Dolors

2011-05-01

The surface microalgal community, including harmful species, dissolved organic matter (DOM), and bacterial and viral populations were studied during an annual cycle (November 2007-October 2008) in a Near-shore (NS) and a Harbour (H) station located in an upwelling area (Sagres, SW Iberian Peninsula). The higher water residence time, water stability and shallowness of harbours in comparison with open waters likely contributed to the differences found between stations regarding chemical variables, statistical correlations and harmful algal proliferations. Also, several differences were noticed from a previous assessment ( Loureiro et al., 2005) including higher SST, lower nitrate and chlorophyll a concentrations, along with a shift in the microplankton community structure from diatom to nanoflagellate predominance. These variations feasibly reflect the response of this dynamic system to regional environmental modifications contributing to the understanding of common patterns in environmental change trends. The division of the sampling period into (1) non-upwelling (Non-Uw), (2) "spin-up" of upwelling (SU-Uw), and (3) "spin-down" and relaxation-downwelling (SD-Rel) stages allowed the identification of natural groupings of microplankton samples by Multi Dimensional Scaling (MDS) analysis. Dissolved organic nitrogen (DON) and viruses were the most significant abiotic and biotic variables, respectively, contributing to the dissimilarities between these stages (SIMPER analysis) and, therefore, potentially affecting the microplankton community structure. Harmful algal species and a stable viral community appeared to be favoured by SD-Rel conditions. Data seem to indicate that both Gymnodinium catenatum and Heterosigma akashiwo, the most abundant potentially harmful species, have been imported into the sampling area. Also, the H location, together with potential retention sites developing around the Cabo de São Vicente upwelling centre, may contribute to the local

Stable isotope database - Transport and fate of nutrient and pathogen loadings into nearshore Puget Sound: consequences for shellfish growing areas

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This project seeks to develop and apply an assessment of shellfish growing area (SGA) vulnerability to closures caused by watershed- and marine-derived pathogens....

Effect of vegetation and surface amelioration on simulated landform evolution of the post-mining landscape at ERA Ranger mine, Northern Territory. Supervising Scientist report 134

International Nuclear Information System (INIS)

Evans, K.G.; Saynor, M.J.; House, T.; The University of Newcastle, Callaghan, NSW; Willgoose, G.

1998-01-01

in similar locations as for the unvegetated and unripped case (ie on steep batter slopes and in the central depression areas of the landform). For the vegetated and ripped condition simulated maximum valley depth in the capping over the tailings containment structure was about 2.2 m. By modelling valley incision, decisions can be made on the minimum depth of tailings cover required to prevent tailings from being exposed to the Environment within a certain time frame. A reduction in thickness of 1 m of capping material over tailings equates to about 1 000 000 Mm 3 /km 2 tailings dam area. This represents a saving of about $1 500 000/km 2 in earthworks. Incorporation of SIBERIA simulations in the design process may result in cost reduction while improving confidence in Environmental protection mechanisms

Mosaic of bathymetry derived from multispectral WV-2 satellite imagery of Baker Island, Pacific Remote Island Areas, Central Pacific.

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetric data derived from a multipectral World View-2 satellite image mosaiced to provide near complete coverage of nearshore terrain around the islands....

Exploring the nearshore marine wind profile from field measurements and numerical hindcast

Science.gov (United States)

del Jesus, F.; Menendez, M.; Guanche, R.; Losada, I.

2012-12-01

Wind power is the predominant offshore renewable energy resource. In the last years, offshore wind farms have become a technically feasible source of electrical power. The economic feasibility of offshore wind farms depends on the quality of the offshore wind conditions compared to that of onshore sites. Installation and maintenance costs must be balanced with more hours and a higher quality of the available resources. European offshore wind development has revealed that the optimum offshore sites are those in which the distance from the coast is limited with high available resource. Due to the growth in the height of the turbines and the complexity of the coast, with interactions between inland wind/coastal orography and ocean winds, there is a need for field measurements and validation of numerical models to understand the marine wind profile near the coast. Moreover, recent studies have pointed out that the logarithmic law describing the vertical wind profile presents limitations. The aim of this work is to characterize the nearshore vertical wind profile in the medium atmosphere boundary layer. Instrumental observations analyzed in this work come from the Idermar project (www.Idermar.es). Three floating masts deployed at different locations on the Cantabrian coast provide wind measurements from a height of 20 to 90 meters. Wind speed and direction are measured as well as several meteorological variables at different heights of the profile. The shortest wind time series has over one year of data. A 20 year high-resolution atmospheric hindcast, using the WRF-ARW model and focusing on hourly offshore wind fields, is also analyzed. Two datasets have been evaluated: a European reanalysis with a ~15 Km spatial resolution, and a hybrid downscaling of wind fields with a spatial resolution of one nautical mile over the northern coast of Spain.. These numerical hindcasts have been validated based on field measurement data. Several parameterizations of the vertical wind

Microfaunal primary succession on the volcanic island Surtsey

DEFF Research Database (Denmark)

Frederiksen, Helle B.; Kraglund, H. O.; Ekelund, F.

2001-01-01

and nematodes were absent and only amoebae and heterotrophic flagellates were found. Most of the protozoan populations we examined were unable to survive salinity levels corresponding to seawater. We therefore conclude that many of soil protozoa populations on Surtsey arrived to the island as airborne cysts...... with different vegetation types (unvegetated soil, soil with one or two plant species, and bird colony soil with a diverse vegetation). We recorded at least 16 nematode taxa and 13 flagellate taxa. Most of these were not reported in previous surveys from Surtsey. On the location with unvegetated soil, ciliates...

Carbon storage in the seagrass meadows of Gazi Bay, Kenya.

Directory of Open Access Journals (Sweden)

Michael N Githaiga

Full Text Available Vegetated marine habitats are globally important carbon sinks, making a significant contribution towards mitigating climate change, and they provide a wide range of other ecosystem services. However, large gaps in knowledge remain, particularly for seagrass meadows in Africa. The present study estimated biomass and sediment organic carbon (Corg stocks of four dominant seagrass species in Gazi Bay, Kenya. It compared sediment Corg between seagrass areas in vegetated and un-vegetated 'controls', using the naturally patchy occurence of seagrass at this site to test the impacts of seagrass growth on sediment Corg. It also explored relationships between the sediment and above-ground Corg, as well as between the total biomass and above-ground parameters. Sediment Corg was significantly different between species, range: 160.7-233.8 Mg C ha-1 (compared to the global range of 115.3 to 829.2 Mg C ha-1. Vegetated areas in all species had significantly higher sediment Corg compared with un-vegetated controls; the presence of seagrass increased Corg by 4-6 times. Biomass carbon differed significantly between species with means ranging between 4.8-7.1 Mg C ha-1 compared to the global range of 2.5-7.3 Mg C ha-1. To our knowledge, these are among the first results on seagrass sediment Corg to be reported from African seagrass beds; and contribute towards our understanding of the role of seagrass in global carbon dynamics.

UNEP-IOC-WMO-IUCN meeting of experts on a long-term global monitoring system of coastal and near-shore phenomena related to climate change, pilot projects and mangroves and coral reefs

Energy Technology Data Exchange (ETDEWEB)

1991-01-01

This meeting was held to develop strategies for long-term global monitoring of coastal and near-shore phenomena related to climate change, specifically mangroves and coral reefs. The agenda included an overview of the Global Ocean Observing System (GOOS) initiative, modules and pilot phase activities. Action plans for the implementation of long-term monitoring of mangrove and coral reef ecosystems were developed including; potential impacts of climate change and sea level rise on mangroves and coral reefs, consideration of parameters, consideration of methodologies, relationships of proposed activities to relevant national, regional and international developments, consideration of monitoring sites, and future implementation.

Seismic scattering attribute for sedimentary classification of nearshore marine quarries for a major beach nourishment project: Case study of Adriatic coastline, Regione Abruzzo (Italy)

Science.gov (United States)

Orlando, Luciana; Contini, Paolo; De Girolamo, Paolo

2017-06-01

Of fundamental importance for any major beach nourishment project using marine quarries is a correct sedimentary classification. The main purpose of such a classification is to identify sand with the appropriate features for beach nourishment. This task is more onerous when quarry sediments are heterogeneous and mixed with silt. This is typical of nearshore marine quarries. The presence of excess silt compromises the use of marine quarries because of the water turbidity that may be induced in the nourished beaches, especially when the beaches are protected by defense structures. Here we discuss the use of scattering amplitude of seismic data, acquired with a pinger source (2-10 kHz), to detect and classify the unconsolidated sediment of a marine quarry. A robust correlation was found between this seismic attribute and the silt content in the sediment. The scattering amplitude was numerically calculated from the seismic data and used to map slices of silt content at different depths. The results have been validated with sedimentary analysis of vibra- and rotary cores, and by the dredged material used for the beach nourishment. The marine quarry produced about 1.200.000 m3 of sand used to nourish eight different beach sites along the Adriatic coasts of the Regione Abruzzo (Italy). The large-scale sedimentary assessment of the area was based on seismic boomer data and the evaluation of the volume of dredged sediments on multibeam data surveyed before and after the exploitation of the quarry. The study shows that this approach is effective in sites with high lateral and vertical variations in the percentage of sand in the sediments.

Underwater Topography Detection in Coastal Areas Using Fully Polarimetric SAR Data

Directory of Open Access Journals (Sweden)

Xiaolin Bian

2017-06-01

Full Text Available Fully polarimetric synthetic aperture radar (SAR can provide detailed information on scattering mechanisms that could enable the target or structure to be identified. This paper presents a method to detect underwater topography in coastal areas using high resolution fully polarimetric SAR data, while less prior information is required. The method is based on the shoaling and refraction of long surface gravity waves as they propagate shoreward. First, the surface scattering component is obtained by polarization decomposition. Then, wave fields are retrieved from the two-dimensional (2D spectra by the Fast Fourier Transformation (FFT. Finally, shallow water depths are estimated from the dispersion relation. Applicability and effectiveness of the proposed methodology are tested by using C-band fine quad-polarization mode RADARSAT-2 SAR data over the near-shore area of the Hainan province, China. By comparing with the values from an official electronic navigational chart (ENC, the estimated water depths are in good agreement with them. The average relative error of the detected results from the scattering mechanisms based method and single polarization SAR data are 9.73% and 11.53% respectively. The validation results indicate that the scattering mechanisms based methodology is more effective than only using the single polarization SAR data for underwater topography detection, and will inspire further research on underwater topography detection with fully polarimetric SAR data.

Measuring the role of seagrasses in regulating sediment surface elevation

KAUST Repository

Potouroglou, Maria

2017-09-13

Seagrass meadows provide numerous ecosystem services and their rapid global loss may reduce human welfare as well as ecological integrity. In common with the other \\'blue carbon\\' habitats (mangroves and tidal marshes) seagrasses are thought to provide coastal defence and encourage sediment stabilisation and surface elevation. A sophisticated understanding of sediment elevation dynamics in mangroves and tidal marshes has been gained by monitoring a wide range of different sites, located in varying hydrogeomorphological conditions over long periods. In contrast, similar evidence for seagrasses is sparse; the present study is a contribution towards filling this gap. Surface elevation change pins were deployed in four locations, Scotland, Kenya, Tanzania and Saudi Arabia, in both seagrass and unvegetated control plots in the low intertidal and shallow subtidal zone. The presence of seagrass had a highly significant, positive impact on surface elevation at all sites. Combined data from the current work and the literature show an average difference of 31 mm per year in elevation rates between vegetated and unvegetated areas, which emphasizes the important contribution of seagrass in facilitating sediment surface elevation and reducing erosion. This paper presents the first multi-site study for sediment surface elevation in seagrasses in different settings and species.

Measuring the role of seagrasses in regulating sediment surface elevation

Science.gov (United States)

Potouroglou, Maria; Bull, James C.; Krauss, Ken W.; Kennedy, Hilary A.; Fusi, Marco; Daffonchio, Daniele; Mangora, Mwita M.; Githaiga, Michael N.; Diele, Karen; Huxham, Mark

2017-01-01

Seagrass meadows provide numerous ecosystem services and their rapid global loss may reduce human welfare as well as ecological integrity. In common with the other ‘blue carbon’ habitats (mangroves and tidal marshes) seagrasses are thought to provide coastal defence and encourage sediment stabilisation and surface elevation. A sophisticated understanding of sediment elevation dynamics in mangroves and tidal marshes has been gained by monitoring a wide range of different sites, located in varying hydrogeomorphological conditions over long periods. In contrast, similar evidence for seagrasses is sparse; the present study is a contribution towards filling this gap. Surface elevation change pins were deployed in four locations, Scotland, Kenya, Tanzania and Saudi Arabia, in both seagrass and unvegetated control plots in the low intertidal and shallow subtidal zone. The presence of seagrass had a highly significant, positive impact on surface elevation at all sites. Combined data from the current work and the literature show an average difference of 31 mm per year in elevation rates between vegetated and unvegetated areas, which emphasizes the important contribution of seagrass in facilitating sediment surface elevation and reducing erosion. This paper presents the first multi-site study for sediment surface elevation in seagrasses in different settings and species.

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Pacific Remote Island Areas since 2014

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

Provenance, Source Rock Characteristics And Paleoweathering Conditions Of The Nearshore Continental Sediments Off Pondicherry, South East Coast Of India

Science.gov (United States)

Natarajan, T.; Seshachalam, S.; Ponniah, J.; Varadhan, R.; M, S.

2008-05-01

Geochemical studies, comprising major elements and trace elements, including the Rare Earth Elements (REE), have been carried out on the modern sediments of inner continental shelf representing nearshore marine environments. Concentrations were normalized with Chondrite and PAAS show LREE enriched and flat HREE patterns with slight positive Eu anomaly which is due to the influence of feldspar rich source materials. The LREE enriched and flat HREE patterns with positive Eu anomaly have been considered as the typical character of post- Archaean Sediments. The La/Th ratio ranges from 1.66 to 8.84 with an average value of 4.09, which indicates a heterogenitic source for the sediments of the study area. The La-Th-Sc ternary plot suggests all the samples fall close to the field dominated by tonalite to granite and away from the basalt and komatiite compositions and appear to be derived from sources enriched in felsic components. The transition metal ratios such as Cr/V, Ni/CO and V/Ni indicate both Archaean and Post-Archaean nature to the sediments indicating that the sediments have been derived from heterogenitic sources. The ternary diagram plot of Th-Hf-Co and La-Th-Sc falls in the field of upper continental crust of post Archaean age. This clearly indicates the terrestrial source for the sediments from the nearby landmass. The data are slightly offset from the upper crustal composition away from the Hf apex. This is probably a result of Zircon concentration. Geochemical data have also helped in ascertaining the weathering trends. The Chemical Index of Alteration (CIA) has been used to quantify the degree of weathering. The calculated CIA values for sediments demonstrate both low CIA values of less than 50 percent (low silicate weathering) and intermediate CIA values (60-70 percent) indicating that the sediments are possibly the product of sedimentary and metasedimentary rocks that have undergone intermediate chemical weathering. On an A—CN—K diagram, the data

Prevalence of antibiotic resistance genes in bacterial communities associated with Cladophora glomerata mats along the nearshore of Lake Ontario.

Science.gov (United States)

Ibsen, Michael; Fernando, Dinesh M; Kumar, Ayush; Kirkwood, Andrea E

2017-05-01

The alga Cladophora glomerata can erupt in nuisance blooms throughout the lower Great Lakes. Since bacterial abundance increases with the emergence and decay of Cladophora, we investigated the prevalence of antibiotic resistance (ABR) in Cladophora-associated bacterial communities up-gradient and down-gradient from a large sewage treatment plant (STP) on Lake Ontario. Although STPs are well-known sources of ABR, we also expected detectable ABR from up-gradient wetland communities, since they receive surface run-off from urban and agricultural sources. Statistically significant differences in aquatic bacterial abundance and ABR were found between down-gradient beach samples and up-gradient coastal wetland samples (ANOVA, Holm-Sidak test, p Cladophora sampled near the STP had the highest bacterial densities overall, including on ampicillin- and vancomycin-treated plates. However, quantitative polymerase chain reaction analysis of the ABR genes ampC, tetA, tetB, and vanA from environmental communities showed a different pattern. Some of the highest ABR gene levels occurred at the 2 coastal wetland sites (vanA). Overall, bacterial ABR profiles from environmental samples were distinguishable between living and decaying Cladophora, inferring that Cladophora may control bacterial ABR depending on its life-cycle stage. Our results also show how spatially and temporally dynamic ABR is in nearshore aquatic bacteria, which warrants further research.

2014 status of the Lake Ontario lower trophic levels

Science.gov (United States)

Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana; Connerton, Michael J.; LaPan, Steve; Biesinger, Zy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

2015-01-01

Soluble reactive phosphorus (SRP) concentrations have been stable in nearshore and offshore habitats since 1998 (0.4 – 3.3 μg/L). SRP concentrations were low in 2014; Apr/May – Oct mean values were Water Quality Agreement of 1978 for offshore waters of Lake Ontario. TP concentrations were low at both nearshore and offshore locations; Apr/May – Oct mean values from individual sites ranged from 4.6 – 9.1 μg/L. Spring TP has declined significantly in the longer data series (since 1981), but not since 1995 indicating stable nutrient loading into Lake Ontario for nearly two decades. It averaged 7.8 μg/L in the nearshore and 5.6 μg/L in the offshore in 2014.Chlorophyll-a and secchi depth values are indicative of oligotrophic conditions in nearshore and offshore habitats. Offshore summer chlorophyll-a declined significantly in both the short- (2000-2014) and long-term (1981-2014) time series at a rate of 4-6% per year. Nearshore chlorophyll-a increased after 2003 but then declined again after 2009. Epilimnetic chlorophyll-a averaged between 0.6 and 1.6 μg/L across sites with no difference between nearshore and offshore habitats. Apr/May – Oct Secchi depth ranged from 4.0 m to 10.8 m at individual sites and was higher in the offshore (average 9.1 m) than nearshore (5.9 m).In 2014, Apr/May – Oct epilimnetic zooplankton density, size, and biomass were not different between the offshore and the nearshore, and there were no differences in epilimnetic biomass between offshore and nearshore areas for any of the zooplankton groups.Zooplankton density and biomass peaked in September, an atypical pattern. This coincided with peaks in calanoid copepod, daphnid, and Holopedium biomass. Holopedium biomass in the nearshore increased significantly since 1995.The predatory cladoceran Cercopagis continued to be abundant in the summer, peaking at ~10 mg/m3in the offshore. Bythotrephes biomass was at its lowest level since 2005 in both offshore and nearshore habitats

Occurrence of Escherichia coli and Enterococci in Cladophora (Chlorophyta) in Nearshore Water and Beach Sand of Lake Michigan†

Science.gov (United States)

Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

2003-01-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches. PMID:12902262

Occurrence of Escherichia coli and enterococci in Cladophora (Chlorophyta) in nearshore water and beach sand of Lake Michigan.

Science.gov (United States)

Whitman, Richard L; Shively, Dawn A; Pawlik, Heather; Nevers, Meredith B; Byappanahalli, Muruleedhara N

2003-08-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (+/- standard errors) of 5.3 (+/- 4.8) and 4.8 (+/- 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P Cladophora mats stored at 4 degrees C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

Copepods of the nearshore waters of Bombay

Digital Repository Service at National Institute of Oceanography (India)

Gajbhiye, S.N.; Stephen, R.; Nair, V.R.; Desai, B.N.

Variability in copepod population was studied along 2 transects off Mahim and Versova (Bombay, Maharashtra, India) during November 1979 to December 1980 covering eight stations from the creek towards the offshore area. Contribution of copepods...

Estimating near-shore wind resources

DEFF Research Database (Denmark)

Floors, Rogier Ralph; Hahmann, Andrea N.; Peña, Alfredo

An evaluation and sensitivity study using the WRF mesoscale model to estimate the wind in a coastal area is performed using a unique data set consisting of scanning, profiling and floating lidars. The ability of the WRF model to represent the wind speed was evaluated by running the model for a four...... grid spacings were performed for each of the two schemes. An evaluation of the wind profile using vertical profilers revealed small differences in modelled mean wind speed between the different set-ups, with the YSU scheme predicting slightly higher mean wind speeds. Larger differences between...... the different simulations were observed when comparing the root-mean-square error (RMSE) between modelled and measured wind, with the ERA interim-based simulations having the lowest errors. The simulations with finer horizontal grid spacing had a larger MSE. Horizontal transects of mean wind speed across...

Geomorphologic and sedimentologic controls on records of flood-induced alluviation in Las Cajas National Park, Ecuador

Science.gov (United States)

Rodbell, D. T.; Bustamante, M. G.; Marks, S.; Abbott, M. B.; Moy, C. M.

2017-12-01

The sediment record from Laguna Pallcacocha in Las Cajas National Park, southern Ecuador (4060 masl; 2°46'S; 79°14'W) has been interpreted to record El Niño floods spanning the Holocene (Rodbell et al., 1999; Moy et al., 2002). The sediment record is unusual for the nearly continuous dark- and light-colored laminations (0.1-2.0 cm thick) that comprise the Holocene. Light laminae typically have erosive basal contacts and fine-upwards, whereas dark laminae possess abrupt or gradational lower contacts and reveal no grain size trends. Light laminae contain 7%), and contain 3-10% biogenic silica. Light laminae represent deposition during periods of increased precipitation, mobilization of unvegetated sediment above the lake, and increased stream discharge, all of which generate density-driven undercurrents. Conversely, dark laminae are deposited relatively slowly by sedimentation of organic matter, some derived from surface soil horizons. Time series analysis of light laminae reveal the ENSO spectral signature (2-8 yr) that evolves through the Holocene. However, none of the sediment cores taken from many nearby lakes reveal an alluvial record comparable in terms of frequency and magnitude to that preserved in Pallcacocha thus raising questions as to the factors responsible for the rich stratigraphy preserved in Pallcacocha, and, moreover, the regional paleoclimatic significance of the Pallcacocha record. A review of lacustrine sediment cores obtained from Las Cajas National Park suggests that drainage basin factors are the primary control on the sedimentologic signal recorded. These factors include bedrock geology, presence of unvegetated sediment exposed on slopes, connectivity of exposed sediment to primary inflow streams, drainage basin slope, drainage basin:lake surface area ratio, and position of lake in paternoster sequence of lakes. Bedrock is comprised of Quaternary silicic ignimbrite, rhyolite, and andesite of the Tarqui Formation. Ignimibrite provides the

Subsurface geology off Bombay with paleoclimatic inferences interpreted from shallow seismic profiles

Digital Repository Service at National Institute of Oceanography (India)

Bhattacharya, G.C.; Almeida, F.; Vora, K.H.; Siddiquie, H.N.

High resolution seismic reflection profiles nearshore areas off Bombay provide information on subsurface geology and permit certain paleoclimatic inferences. Three sedimentary units overlie the acoustic basement: late Pleistocene consolidated...

Ecosystem monitoring information collected from Norseman II in Beaufort Sea for the ANIMIDA III project from 2014-07-31 to 2015-08-12 (NCEI Accession 0162530)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains physical, chemical, and biological data collected during research cruises for the Arctic Nearshore Impact Monitoring in Development Area...

Wave Height Estimation from Shadowing Based on the Acquired X-Band Marine Radar Images in Coastal Area

Directory of Open Access Journals (Sweden)

Yanbo Wei

2017-08-01

Full Text Available In this paper, the retrieving significant wave height from X-band marine radar images based on shadow statistics is investigated, since the retrieving accuracy can not be seriously affected by environmental factors and the method has the advantage of without any external reference to calibrate. However, the accuracy of the significant wave height estimated from the radar image acquired at the near-shore area is not ideal. To solve this problem, the effect of water depth is considered in the theoretical derivation of estimated wave height based on the sea surface slope. And then, an improved retrieving algorithm which is suitable for both in deep water area and shallow water area is developed. In addition, the radar data are sparsely processed in advance in order to achieve high quality edge image for the requirement of shadow statistic algorithm, since the high resolution radar images will lead to angle-blurred for the image edge detection and time-consuming in the estimation of sea surface slope. The data acquired from Pingtan Test Base in Fujian Province were used to verify the effectiveness of the proposed algorithm. The experimental results demonstrate that the improved method which takes into account the water depth is more efficient and effective and has better performance for retrieving significant wave height in the shallow water area, compared to the in situ buoy data as the ground truth and that of the existing shadow statistic method.

Otolith analysis of pre-restoration habitat use by Chinook salmon in the delta-flats and nearshore regions of the Nisqually River Estuary

Science.gov (United States)

Lind-Null, Angie; Larsen, Kim

2010-01-01

The Nisqually Fall Chinook population is one of 27 salmon stocks in the Puget Sound (Washington) evolutionarily significant unit listed as threatened under the federal Endangered Species Act (ESA). Extensive restoration of the Nisqually River delta ecosystem is currently taking place to assist in recovery of the stock as juvenile Fall Chinook salmon are dependent on the estuary. A pre-restoration baseline that includes the characterization of life history strategies, estuary residence times, growth rates, and habitat use is needed to evaluate the potential response of hatchery and natural origin Chinook salmon to restoration efforts and to determine restoration success. Otolith analysis was selected as a tool to examine Chinook salmon life history, growth, and residence in the Nisqually River estuary. Previously funded work on samples collected in 2004 (marked and unmarked) and 2005 (unmarked only) partially established a juvenile baseline on growth rates and length of residence associated with various habitats (freshwater, forested riverine tidal, emergent forested transition, estuarine emergent marsh, delta-flats and nearshore). However, residence times and growth rates for the delta-flats (DF) and nearshore (NS) habitats have been minimally documented due to small sample sizes. The purpose of the current study is to incorporate otolith microstructural analysis using otoliths from fish collected within the DF and NS habitats during sampling years 2004-08 to increase sample size and further evaluate between-year variation in otolith microstructure. Our results from this analysis indicated the delta-flats check (DFCK) on unmarked and marked Chinook samples in 2005-08 varied slightly in appearance from that seen on samples previously analyzed only from 2004. A fry migrant life history was observed on otoliths of unmarked Chinook collected in 2005, 2007, and 2008. Generally, freshwater mean increment width of unmarked fish, on average, was smaller compared to marked

Coral colonisation of an artificial reef in a turbid nearshore environment, Dampier Harbour, western Australia.

Directory of Open Access Journals (Sweden)

David Blakeway

Full Text Available A 0.6 hectare artificial reef of local rock and recycled concrete sleepers was constructed in December 2006 at Parker Point in the industrial port of Dampier, western Australia, with the aim of providing an environmental offset for a nearshore coral community lost to land reclamation. Corals successfully colonised the artificial reef, despite the relatively harsh environmental conditions at the site (annual water temperature range 18-32°C, intermittent high turbidity, frequent cyclones, frequent nearby ship movements. Coral settlement to the artificial reef was examined by terracotta tile deployments, and later stages of coral community development were examined by in-situ visual surveys within fixed 25 x 25 cm quadrats on the rock and concrete substrates. Mean coral density on the tiles varied from 113 ± 17 SE to 909 ± 85 SE per m(2 over five deployments, whereas mean coral density in the quadrats was only 6.0 ± 1.0 SE per m(2 at eight months post construction, increasing to 24.0 ± 2.1 SE per m(2 at 62 months post construction. Coral taxa colonising the artificial reef were a subset of those on the surrounding natural reef, but occurred in different proportions--Pseudosiderastrea tayami, Mycedium elephantotus and Leptastrea purpurea being disproportionately abundant on the artificial reef. Coral cover increased rapidly in the later stages of the study, reaching 2.3 ± 0.7 SE % at 62 months post construction. This study indicates that simple materials of opportunity can provide a suitable substrate for coral recruitment in Dampier Harbour, and that natural colonisation at the study site remains sufficient to initiate a coral community on artificial substrate despite ongoing natural and anthropogenic perturbations.

[Near ultraviolet absorption spectral properties of chromophoric dissolved organic matter in the north area of Yellow Sea].

Science.gov (United States)

Wang, Lin; Zhao, Dong-Zhi; Yang, Jian-Hong; Chen, Yan-Long

2010-12-01

Chromophoric dissolved organic matter (CDOM) near ultraviolet absorption spectra contains CDOM molecular structure, composition and other important physical and chemical information. Based on the measured data of CDOM absorption coefficient in March 2009 in the north area of Yellow Sea, the present paper analyzed near ultraviolet absorption spectral properties of CDOM. The results showed that due to the impact of near-shore terrigenous input, the composition of CDOM is quite different in the north area of Yellow Sea, and this area is a typical case II water; fitted slope with specific range of spectral band and absorption coefficient at specific band can indicate the relative size of CDOM molecular weight, correlation between spectral slope of the Sg,275-300), Sg,300-350, Sg,350-400 and Sg,250-275 and the relative size of CDOM molecular weight indicative parameter M increases in turn and the highest is up to 0.95. Correlation between a(g)(lambda) and M value increases gradually with the increase in wavelength, and the highest is up to 0.92 at 400 nm; being correlated or not between spectral slope and absorption coefficient is decided by the fitting-band wavelength range for the spectra slope and the wavelength for absorption coefficient. Correlation between Sg,275-300 and a(g)(400) is the largest, up to 0.87.

Bioremediation and phytoremediation of total petroleum hydrocarbons (TPH) under various conditions.

Science.gov (United States)

McIntosh, Patrick; Schulthess, Cristian P; Kuzovkina, Yulia A; Guillard, Karl

2017-08-03

Remediation of contaminated soils is often studied using fine-textured soils rather than low-fertility sandy soils, and few studies focus on recontamination events. This study compared aerobic and anaerobic treatments for remediation of freshly introduced used motor oil on a sandy soil previously phytoremediated and bioacclimated (microorganisms already adapted in the soil environment) with some residual total petroleum hydrocarbon (TPH) contamination. Vegetated and unvegetated conditions to remediate anthropogenic fill containing residual TPH that was spiked with nonaqueous phase liquids (NAPLs) were evaluated in a 90-day greenhouse pot study. Vegetated treatments used switchgrass (Panicum virgatum). The concentration of aerobic bacteria were orders of magnitude higher in vegetated treatments compared to unvegetated. Nevertheless, final TPH concentrations were low in all saturated soil treatments, and high in the presence of switchgrass. Concentrations were also low in unvegetated pots with fertilizer. Acclimated indigenous microbial communities were shown to be more effective in breaking down hydrocarbons than introducing microbes from the addition of plant treatments in sandy soils. Remediation of fresh introduced NAPLs on pre-phytoremediated and bioacclimated soil was most efficient in saturated, anaerobic environments, probably due to the already pre-established microbial associations, easily bioavailable contaminants, and optimized soil conditions for microbial establishment and survival.

Occurrence and sources of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in surficial sediments of Lakes Superior and Huron

International Nuclear Information System (INIS)

Shen Li; Gewurtz, Sarah B.; Reiner, Eric J.; MacPherson, Karen A.; Kolic, Terry M.; Khurana, Vin; Helm, Paul A.; Howell, E. Todd; Burniston, Debbie A.; Brindle, Ian D.; Marvin, Chris H.

2009-01-01

Concentrations and congener profile patterns of 2378-substituted PCDD/Fs and DLPCBs in offshore, nearshore and tributary sediments of Lakes Superior and Huron are reported, and spatial trends and source contributions assessed. PCDD/F concentrations ranged from 5 to 18 000 pg/g dw (Lake Superior) and 3 to 6100 pg/g dw (Lake Huron); DLPCBs ranged from 9 to 11 000 pg/g dw (Lake Superior) and 9 to 27 000 pg/g dw (Lake Huron). Our analysis indicated atmospheric deposition is a primary source to depositional areas of both lakes; however, greater PCDD/F and DLPCB concentrations were observed at several nearshore and tributary sites, and were attributed to corresponding land use in the watershed. Statistical analysis and pattern comparison suggested that industrial inputs mainly associated with wood treatment plants, pulp and paper mills, mining operations, and chlorine-based chemical manufacturing also contributed to contamination by PCDD/Fs and DLPCBs in certain nearshore and offshore areas of Lakes Superior and Huron. - Lake-wide 2378-PCDD/F and DLPCB concentrations, spatial trends, and congener patterns are first reported in Lakes Superior and Huron sediments

The Use of Digital Multispectral Video for Littoral Zone Applications

National Research Council Canada - National Science Library

Fischer, Robert

1997-01-01

.... These information categories would then be used to assist in tactical near-shore decisions, such as cross country mobility, avenues of approach, bivouac sites, and landing areas, and to also provide...

Distribution characteristics of radium isotopes and their influence factors in the water of Jiaozhou Bay area

International Nuclear Information System (INIS)

Wang Bo; Guo Zhanrong; Yuan Xiaojie; Zhang Bin; Ma Zhiyong; Liu Jie

2014-01-01

Background: The interaction between continental and oceanic process is much intense in coastal region. The terrestrial freshwater mixes with seawater here which leads to the chemical constituents in water undergo rapid change. Purpose: The aim is to analyze and study the distribution characteristics of 224 Ra and 226 Ra and their influence factors in the water of Jiaozhou Bay area. Methods: The water samples of 224 Ra and 226 Ra were collected from groundwater, river water and seawater around the Jiaozhou Bay from April to May, 2012. In the laboratory, the activities of 224 Ra absorbed on the Mn-fiber were measured through the continuous emanation method. Finally, the Mn-fiber was sealed for more than 7 days, and the activities of 226 Ra absorbed on the Mn-fiber were measured through the direct emanation method. Results: The results show that the activities of 224 Ra and 226 Ra in groundwater and river water are much higher in the granitic area which has higher concentration of 232 Th and 238 U. Because of mixing with seawater, the salinity of groundwater and river water in coastal region rises which leads to the increasing amounts of 224 Ra and 226 Ra desorbed from the particles, resulting in higher activities of 224 Ra and 226 Ra in coastal region. Affected by the input of river (dissolved and desorbed from suspended particles) and submarine groundwater discharge (SGD), the activities of 224 Ra and 226 Ra are relatively higher in nearshore seawater, then with the decay of 224 Ra and mixing dilution effect of the offshore seawater, the activities of 224 Ra gradually decrease from nearshore region to the open ocean. The activities of 226 Ra in the seawater of Jiaozhou Bay remain high-level values, and there are only a few zones of low 226 Ra activities. The main reasons are that the activities of 226 Ra from terrestrial freshwater are close to those from offshore seawater and the half-life of 226 Ra is very long. Conclusion: The activities of 224 Ra and 226 Ra in

Use of regression‐based models to map sensitivity of aquatic resources to atmospheric deposition in Yosemite National Park, USA

Science.gov (United States)

Clow, David W.; Nanus, Leora; Huggett, Brian

2010-01-01

An abundance of exposed bedrock, sparse soil and vegetation, and fast hydrologic flushing rates make aquatic ecosystems in Yosemite National Park susceptible to nutrient enrichment and episodic acidification due to atmospheric deposition of nitrogen (N) and sulfur (S). In this study, multiple linear regression (MLR) models were created to estimate fall‐season nitrate and acid neutralizing capacity (ANC) in surface water in Yosemite wilderness. Input data included estimated winter N deposition, fall‐season surface‐water chemistry measurements at 52 sites, and basin characteristics derived from geographic information system layers of topography, geology, and vegetation. The MLR models accounted for 84% and 70% of the variance in surface‐water nitrate and ANC, respectively. Explanatory variables (and the sign of their coefficients) for nitrate included elevation (positive) and the abundance of neoglacial and talus deposits (positive), unvegetated terrain (positive), alluvium (negative), and riparian (negative) areas in the basins. Explanatory variables for ANC included basin area (positive) and the abundance of metamorphic rocks (positive), unvegetated terrain (negative), water (negative), and winter N deposition (negative) in the basins. The MLR equations were applied to 1407 stream reaches delineated in the National Hydrography Data Set for Yosemite, and maps of predicted surface‐water nitrate and ANC concentrations were created. Predicted surface‐water nitrate concentrations were highest in small, high‐elevation cirques, and concentrations declined downstream. Predicted ANC concentrations showed the opposite pattern, except in high‐elevation areas underlain by metamorphic rocks along the Sierran Crest, which had relatively high predicted ANC (>200 μeq L−1). Maps were created to show where basin characteristics predispose aquatic resources to nutrient enrichment and acidification effects from N and S deposition. The maps can be used to help guide

Use of regression-based models to map sensitivity of aquatic resources to atmospheric deposition in Yosemite National Park, USA

Science.gov (United States)

Clow, D. W.; Nanus, L.; Huggett, B. W.

2010-12-01

An abundance of exposed bedrock, sparse soil and vegetation, and fast hydrologic flushing rates make aquatic ecosystems in Yosemite National Park susceptible to nutrient enrichment and episodic acidification due to atmospheric deposition of nitrogen (N) and sulfur (S). In this study, multiple-linear regression (MLR) models were created to estimate fall-season nitrate and acid neutralizing capacity (ANC) in surface water in Yosemite wilderness. Input data included estimated winter N deposition, fall-season surface-water chemistry measurements at 52 sites, and basin characteristics derived from geographic information system layers of topography, geology, and vegetation. The MLR models accounted for 84% and 70% of the variance in surface-water nitrate and ANC, respectively. Explanatory variables (and the sign of their coefficients) for nitrate included elevation (positive) and the abundance of neoglacial and talus deposits (positive), unvegetated terrain (positive), alluvium (negative), and riparian (negative) areas in the basins. Explanatory variables for ANC included basin area (positive) and the abundance of metamorphic rocks (positive), unvegetated terrain (negative), water (negative), and winter N deposition (negative) in the basins. The MLR equations were applied to 1407 stream reaches delineated in the National Hydrography Dataset for Yosemite, and maps of predicted surface-water nitrate and ANC concentrations were created. Predicted surface-water nitrate concentrations were highest in small, high-elevation cirques, and concentrations declined downstream. Predicted ANC concentrations showed the opposite pattern, except in high-elevation areas underlain by metamorphic rocks along the Sierran Crest, which had relatively high predicted ANC (>200 µeq L-1). Maps were created to show where basin characteristics predispose aquatic resources to nutrient enrichment and acidification effects from N and S deposition. The maps can be used to help guide development of

ECORS Truc Vert'08: a Multi-Institutional International Nearshore Field Experiment

Science.gov (United States)

Senechal, N.; Ardhuin, F.

2008-12-01

A large multi-institutional international field experiment (ECORS Truc Vert'08) was conducted Feb-April 2008 on the southern part of the French Atlantic coastline. More than 120 scientists, students and technicians participated to this effort coming from 3 continents and 6 countries : Australia (University of New South Wales), France (SHOM, University Bordeaux I, University Pau et Pays de l'Adour, University Sud-Toulon Var, University Joseph Fourier, University Perpignan, BRGM, University Lyon 1), Great Britain (Plymouth University), New Zealand (NIWA), The Netherlands (Delft University of Technology, University of Utrecht) and USA (Naval Postgraduate School, University of Miami, Franklin and Marshall College). Truc Vert beach is a high-energy, dynamic, macrotidal, double-barred beach representative of most of the beaches on this 250 km long coastline. The inner bar can go through all the states within the intermediate classification and usually exhibits a transverse bar and rip morphology (380 m alongshore wavelength). The outer bar is changeable from linear to crescentic (720 m alongshore wavelength). The goals were to measure the hydrodynamic processes, sedimentary processes and morphologic responses on a macrotidal beach during energetic wave conditions and covering a large spectrum of spatial and temporal scales. This dataset will facilitate the validation of surf zone wave, hydrodynamic and morphodynamic models, it will lend insight into the morphodynamic evolution of three dimensional beaches and it will fill the gaps in previous nearshore data sets. A wide range of unique instrumentation was used including continuously sampled 2Hz high-resolution surfzone video cameras, daily topographic surveys, bathymetric surveys from the French naval vessels and personal watercrafts, high frequency velocity and pressure sensors, acoustic Doppler current profilers, sediment transport devices, sand porosity and grain size devices, and position-tracking drifters

Influence of PAHs among other coastal environmental variables on total and PAH-degrading bacterial communities.

Science.gov (United States)

Sauret, Caroline; Tedetti, Marc; Guigue, Catherine; Dumas, Chloé; Lami, Raphaël; Pujo-Pay, Mireille; Conan, Pascal; Goutx, Madeleine; Ghiglione, Jean-François

2016-03-01

We evaluated the relative impact of anthropogenic polycyclic aromatic hydrocarbons (PAHs) among biogeochemical variables on total, metabolically active, and PAH bacterial communities in summer and winter in surface microlayer (SML) and subsurface seawaters (SSW) across short transects along the NW Mediterranean coast from three harbors, one wastewater effluent, and one nearshore observatory reference site. At both seasons, significant correlations were found between dissolved total PAH concentrations and PAH-degrading bacteria that formed a gradient from the shore to nearshore waters. Accumulation of PAH degraders was particularly high in the SML, where PAHs accumulated. Harbors and wastewater outfalls influenced drastically and in a different way the total and active bacterial community structure, but they only impacted the communities from the nearshore zone (PAH concentrations on the spatial and temporal dynamic of total and active communities in this area, but this effect was putted in perspective by the importance of other biogeochemical variables.

Occurrence of zebra mussels in near-shore areas of western Lake Erie

Science.gov (United States)

Custer, Christine M.; Custer, T.W.

1997-01-01

Zebra mussels (Dreissena polymorpha) invaded the Great Lakes in the mid-1980s and quickly reached high densities. The objective of this study was to determine current consumption of zebra mussels by waterfowl in the Great Lakes region. Feeding Lesser Scaups (Aythya affinis), Greater Scaups (A. marila), Canvasbacks (A. valisineria), Redheads (A. americana), Buffleheads (Bucephala albeola) and Common Goldeneyes (B. clangula) were collected in western Lake Erie and in Lake St. Clair between fall and spring, 1992-1993 to determine food habits. All 10 Redheads, 97% of Lesser Scaups, 83% of Goldeneyes, 60% of Buffleheads and 9% of Canvasbacks contained one or more zebra mussels in their upper gastrointestinal tracts. The aggregate percent of zebra mussels in the diet of Lesser Scaups was higher in Lake Erie (98.6%) than in Lake St. Clair (54.4%). Zebra mussels, (aggregate percent) dominated the diet of Common Goldeneyes (79.2%) but not in Buffleheads (23.5%), Redheads (21%) or Canvasbacks (9%). Lesser Scaups from Lake Erie fed on larger zebra mussels ( = 10.7 i?? 0.66 mm SE) than did Lesser Scaups from Lake St. Clair ( = 4.4 i?? 0.22 mm). Lesser Scaups, Buffleheads and Common Goldeneyes from Lake Erie consumed zebra mussels of similar size.

Using SST and land cover data from EO Missions for improved mesoscale modelling of the coastal zone

DEFF Research Database (Denmark)

Karagali, Ioanna; Floors, Rogier Ralph; Lea, Guillaume

was to evaluate the uncertainty of the modelled wind in the coastal zone and further improve it. Moreover LIDAR measurements were used to evaluate the wind speed retrieval from high resolution SAR systems (Sentinel-1 and TerraSAR-X). The WRF model used a high-resolution satellite SST reanalysis product from...... be implemented in the meso-scale model to better represent the actual conditions in the study area. Such improvements are expected to strengthen the model’s ability to represent land- sea and air-sea interactions, the atmospheric stability and the local topographic features that partly affect the coastal zone......Existing wind measurements in near-shore and offshore areas are sparse and scarce, therefore simulations from state-of-the-art meso-scale models are used for wind resource predictions. In coastal and near-shore areas, models are inaccurate and uncertain, mainly because of numerical approximations...

Habitat capacity for Sacramento delta - Life Cycle Modeling of Life History Diversity and Habitat Relationships

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The goals of this project are to examine 1) the relative importance of multiple aquatic habitats (streams, estuaries, and nearshore areas, for example) used by...

Temporal and geographic variation in fish communities of lower Cook Inlet, Alaska

Science.gov (United States)

Robards, Martin D.; Piatt, John F.; Kettle, Arthur B.; Abookire, Alisa A.

1999-01-01

Nearshore and shelf fish communities were studied in three areas of lower Cook Inlet, Alaska: the Barren Islands (oceanic and well-mixed waters), Kachemak Bay (mixed oceanic waters with significant freshwater runoff), and Chisik Island (estuarine waters). Fish were sampled with beach seines (n=413 sets) and midwater trawls (n=39 sets). We found that lower Cook Inlet supported a diverse nearshore fish community of at least 52 species. Fifty of these species were caught in Kachemak Bay, 24 at Chisik Island, and 12 at the Barren Islands. Pacific sand lance dominated Barren Islands and Kachemak Bay nearshore habitats, comprising 99% and 71% of total individuals, respectively. The nearshore Chisik Island fish community was not dominated by any one species; instead it exhibited higher diversity. These spatial differences appeared linked to local oceanographic regimes and sediment influx. Analysis of historical data revealed that the nearshore Kachemak Bay fish community changed significantly between 1976 and 1996, showing increased diversity and abundance in several taxa, notably gadids, salmonids, pleuronectids, and sculpins. Decadal differences appeared to be related to large-scale climate changes in the North Pacific. Catches of most taxa peaked in May-August, and were low during other months of the year. Several species were present for only part of the summer. Species composition of seine catches differed significantly between consecutive high and low tides, but not between consecutive sets or years. Midwater trawls took 26 species, 14 of which were present in Kachemak Bay, 19 near Chisik Island, and 7 at the Barren Islands. Community structures in shelf and nearshore waters were similar: diversity was high and abundance low at Chisik Island, whereas a few abundant species dominated at both Kachemak Bay and the Barren Islands. In addition, the low fish abundance near Chisik Island appeared to be related to declining seabird numbers at this colony.

Spatial distribution of nearshore fish in the vicinity of two thermal generating stations, Nanticoke and Douglas Point, on the Great Lakes

International Nuclear Information System (INIS)

Minns, C.K.; Kelso, J.R.M.; Hyatt, W.

1978-01-01

At Nanticoke, Lake Erie, 1974, mean fish density varied considerably, range 162-14 204/10 000 m 3 , as estimated by digital acoustic fish enumeration. At Douglas Point, Lake Huron, 1975, mean density varied less, range 108-671/10 000 m 3 . At both sites fish densities were generally greatest in the shallowest, 3-5 m, depths. At Nanticoke, where the nearshore has low relief, there were no distinguishable communities. At Douglas Point, where depth increases rapidly offshore, there was evidence of benthic and pelagic communities. There was no evidence of altered fish distribution in relation to temperature. At Nanticoke there was no vertical variation in temperature and no vertical response was to be expected. At Douglas Point there was thermal stratification present in the summer and there was no apparent response. The influence of incident radiation was uncertain because of the effects of diurnal migrations. At both locations fish were clustered horizontally to varying degrees in the spring and fall, while in the summer fish were distributed more evenly. Densest clusters were usually in the vicinity of the turbulent discharge at both locations. The lack of temperature response and the similarity of Nanticoke with situations at nearby streams on Lake Erie suggest that the fish are responding to currents and perhaps topography. (author)

Shallow-Water Benthic Habitats of Southwest Puerto Rico: Accuracy Assessment Site Locations

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of two areas in Southwest Puerto Rico (PR), including the Guanica Bay/La Parguera...

Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_502736_PS

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of two areas in Southwest Puerto Rico (PR), including the Guanica Bay/La Parguera...

Shallow-Water Benthic Habitats of Southwest Puerto Rico: GeoEye Image po_483895_PS

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of two areas in Southwest Puerto Rico (PR), including the Guanica Bay/La Parguera...

Shallow-Water Benthic Habitats of Southwest Puerto Rico: Ground Validation Site Locations

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of two areas in Southwest Puerto Rico (PR), including the Guanica Bay/La Parguera...

Shallow-Water Benthic Habitats of Southwest Puerto Rico

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Shallow-water (<30m) benthic habitat maps of the nearshore marine environment of two areas in Southwest Puerto Rico (PR), including the Guanica Bay/La Parguera...

EPA oyster project: nitrogen in water. - Transport and fate of nutrient and pathogen loadings into nearshore Puget Sound: consequences for shellfish growing areas

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This project seeks to develop and apply an assessment of shellfish growing area (SGA) vulnerability to closures caused by watershed- and marine-derived pathogens....

The relationship between mineralisation and depositional environment in Early Proterozoic metasediments of the Pine Creek Geosyncline

International Nuclear Information System (INIS)

Needham, R.S.; Stuart-Smith, P.G.

1984-01-01

Recent geological mapping has indicated changes to the stratigraphy of the Pine Creek Geosyncline. The new stratigraphy and interpreted depositional environments are examined in relation to the distribution and genesis of stratabound mineral deposits. Basinward correlations are made with near-shore carbonate and psammite-rudite units in the Rum Jungle region. Most other units in the same region are condensed, indicating long-lived supratidal, intertidal or shallow conditions during most of the depositional cycle. Units containing most of the mineralisation represent the earliest near-shore developments of strongly reducing partly pelitic and evaporitic conditions and contain mainly uranium and base metals. Areas of potential mineralisation include near-shore environments in the north, and carbonate reefs along growth faults. Two suites of postorogenic felsic volcanics and related sediments deposited in shallow water within and around northwest and east-northeast rift systems, overlie the metasediments of the Pine Creek Geosyncline in the south. The suites have potential for volcanogenic deposits, mostly of uranium, gold and copper

Geomorphology and surficial geology of the western continental shelf and slope of India: A review

Digital Repository Service at National Institute of Oceanography (India)

Rao, V.P.; Wagle, B.G.

Coastal geology and geomorphology of the area and nearshore currents played a significant role in the distribution of placer minerals off Kerala and Maharashtra. Transport and sedeimentation of fine-grained materials at places on the shelf...

Seagrass habitat complexity and macroinvertebrate abundance in Lakshadweep coral reef lagoons, Arabian Sea

Science.gov (United States)

Ansari, Z. A.; Rivonker, C. U.; Ramani, P.; Parulekar, A. H.

1991-09-01

Macrofauna of seagrass community in the five Lakshadweep atolls were studied and compared. The associated epifaunal and infaunal taxa comprising nine major taxonomic groups, showed significant differences in the total number of individuals (1041 8411 m-2) among sites and habitats. The density of macrofauna was directly related to mean macrophytic biomass (405 895 g wet wt. m-2). The fauna was dominated by epifaunal polychaetes, amphipods and isopods in the vegetated areas. When compared with the density of nearby unvegetated areasleft( {bar x = 815{text{m }}^{ - 2} } right), seagrass meadows harbour a denser and richer macroinvertebrate assemblageleft( {bar x = 4023{text{m }}^{ - 2} } right).

Innovative GOCI algorithm to derive turbidity in highly turbid waters: a case study in the Zhejiang coastal area.

Science.gov (United States)

Qiu, Zhongfeng; Zheng, Lufei; Zhou, Yan; Sun, Deyong; Wang, Shengqiang; Wu, Wei

2015-09-21

An innovative algorithm is developed and validated to estimate the turbidity in Zhejiang coastal area (highly turbid waters) using data from the Geostationary Ocean Color Imager (GOCI). First, satellite-ground synchronous data (n = 850) was collected from 2014 to 2015 using 11 buoys equipped with a Yellow Spring Instrument (YSI) multi-parameter sonde capable of taking hourly turbidity measurements. The GOCI data-derived Rayleigh-corrected reflectance (R(rc)) was used in place of the widely used remote sensing reflectance (R(rs)) to model turbidity. Various band characteristics, including single band, band ratio, band subtraction, and selected band combinations, were analyzed to identify correlations with turbidity. The results indicated that band 6 had the closest relationship to turbidity; however, the combined bands 3 and 6 model simulated turbidity most accurately (R(2) = 0.821, pcoastal waters is feasible. As an example, the developed model was applied to 8 hourly GOCI images on 30 December 2014. Three cross sections were selected to identify the spatiotemporal variation of turbidity in the study area. Turbidity generally decreased from near-shore to offshore and from morning to afternoon. Overall, the findings of this study provide a simple and practical method, based on GOCI data, to estimate turbidity in highly turbid coastal waters at high temporal resolutions.

Wave-induced coherent turbulence structures and sediment resuspension in the nearshore of a prototype-scale sandy barrier beach

Science.gov (United States)

Kassem, Hachem; Thompson, Charlotte E. L.; Amos, Carl L.; Townend, Ian H.

2015-10-01

The suspension of sediments by oscillatory flows is a complex case of fluid-particle interaction. The aim of this study is to provide insight into the spatial (time) and scale (frequency) relationships between wave-generated boundary layer turbulence and event-driven sediment transport beneath irregular shoaling and breaking waves in the nearshore of a prototype sandy barrier beach, using data collected through the Barrier Dynamics Experiment II (BARDEX II). Statistical, quadrant and spectral analyses reveal the anisotropic and intermittent nature of Reynolds' stresses (momentum exchange) in the wave boundary layer, in all three orthogonal planes of motion. The fractional contribution of coherent turbulence structures appears to be dictated by the structural form of eddies beneath plunging and spilling breakers, which in turn define the net sediment mobilisation towards or away from the barrier, and hence ensuing erosion and accretion trends. A standing transverse wave is also observed in the flume, contributing to the substantial skewness of spanwise turbulence. Observed low frequency suspensions are closely linked to the mean flow (wave) properties. Wavelet analysis reveals that the entrainment and maintenance of sediment in suspension through a cluster of bursting sequence is associated with the passage of intermittent slowly-evolving large structures, which can modulate the frequency of smaller motions. Outside the boundary layer, small scale, higher frequency turbulence drives the suspension. The extent to which these spatially varied perturbation clusters persist is associated with suspension events in the high frequency scales, decaying as the turbulent motion ceases to supply momentum, with an observed hysteresis effect.

Occurrence of Escherichia coli and enterococci in Cladophora (Clorophyta) in nearshore water and beach sand of Lake Michigan

Science.gov (United States)

Whitman, Richard L.; Shively, Dawn A.; Pawlik, Heather; Nevers, Meredith B.; Byappanahalli, Muruleedhara N.

2003-01-01

Each summer, the nuisance green alga Cladophora (mostly Cladophora glomerata) amasses along Lake Michigan beaches, creating nearshore anoxia and unsightly, malodorous mats that can attract problem animals and detract from visitor enjoyment. Traditionally, elevated counts of Escherichia coli are presumed to indicate the presence of sewage, mostly derived from nearby point sources. The relationship between fecal indicator bacteria and Cladophora remains essentially unstudied. This investigation describes the local and regional density of Escherichia coli and enterococci in Cladophora mats along beaches in the four states (Wisconsin, Illinois, Indiana, and Michigan) bordering Lake Michigan. Samples of Cladophora strands collected from 10 beaches (n = 41) were assayed for concentrations of E. coli and enterococci during the summer of 2002. Both E. coli and enterococci were ubiquitous (up to 97% occurrence), with overall log mean densities (± standard errors) of 5.3 (± 4.8) and 4.8 (± 4.5) per g (dry weight). E. coli and enterococci were strongly correlated in southern Lake Michigan beaches (P R2 = 0.73, n = 17) but not in northern beaches (P = 0.892, n = 16). Both E. coli and enterococci survived for over 6 months in sun-dried Cladophora mats stored at 4°C; the residual bacteria in the dried alga readily grew upon rehydration. These findings suggest that Cladophora amassing along the beaches of Lake Michigan may be an important environmental source of indicator bacteria and call into question the reliability of E. coli and enterococci as indicators of water quality for freshwater recreational beaches.

Mineralogical and geochemical aspects of the marine sediments off Goa

Digital Repository Service at National Institute of Oceanography (India)

Paropkari, A.L.

-Mati beaches and off Mandovi and Zuari Rivers indicates predominant metamorphic source rocks. In the nearshore areas the concentrations of organic carbon and phosphorus have been controlled by detrital supply and organic productivity and that of carbonate...

Ecosystem services provided by pacific NW Estuaries: State of knowledge

Science.gov (United States)

Coastal regions in the United States are rapidly developing areas, with increasing urbanization and growing populations. Estuarine and nearshore coastal marine waters provide valuable ecosystem services to resident and transient human communities. In the Pacific Northwest (PNW)...

Ecosystem services provided by Pacific NW estuaries: State of knowledge - March 3, 2011

Science.gov (United States)

Coastal regions in the United States are rapidly developing areas, with increasing urbanization and growing populations. Estuarine and nearshore coastal marine waters provide valuable ecosystem services to resident and transient human communities. In the Pacific Northwest (PNW) ...

Distribution of microbial populations and their relationship with environmental variables in the North Yellow Sea, China

Science.gov (United States)

Bai, Xiaoge; Wang, Min; Liang, Yantao; Zhang, Zhifeng; Wang, Fang; Jiang, Xuejiao

2012-03-01

In order to understand the large-scale spatial distribution characteristics of picoplankton, nanophytoplankton and virioplankton and their relationship with environmental variables in coastal and offshore waters, flow cytometry (FCM) was used to analyze microbial abundance of samples collected in summer from four depths at 36 stations in the North Yellow Sea (NYS). The data revealed spatial heterogeneity in microbial populations in the offshore and near-shore waters of the NYS during the summer. For the surface layer, picoeukaryotes were abundant in the near-shore waters, Synechococcus was abundant in the offshore areas, and bacterial and viral abundances were high in the near-shore waters around the Liaodong peninsula. In the near-shore waters, no significant vertical variation of picophytoplankton (0.2-2μm) abundance was found. However, the nanophytoplankton abundance was higher in the upper layers (from the surface to 10 m depth) than in the bottom layer. For the offshore waters, both pico- and nanophytoplankton (2-20μm) abundance decreased sharply with depth in the North Yellow Sea Cold Water Mass (NYSCWM). But, for the vertical distribution of virus and bacteria abundance, no significant variation was observed in both near-shore and offshore waters. Autotrophic microbes were more sensitive to environmental change than heterotrophic microbes and viruses. Viruses showed a positive correlation with bacterial abundance, suggesting that the bacteriophage might be prominent for virioplankton (about 0.45μm) in summer in the NYS and that viral abundance might play an important role in microbial loop functions.

Deriving nearshore wave climate along South African coast

CSIR Research Space (South Africa)

Rossouw, M

2015-04-01

Full Text Available The present study addressed aspects of the highly interrelated study area of coastal safety and vulnerability, climate change and setback lines for South African coast. A medium resolution numerical wave analysis was undertaken, in the form...

Trophic dynamics of few selected nearshore coastal finfishes with emphasis on prawns as prey item

Science.gov (United States)

Velip, Dinesh T.; Rivonker, Chandrashekher U.

2018-06-01

A trophic dynamic study of marine finfishes was undertaken based on stomach content analysis of twenty four species (N = 1742) collected from the nearshore coastal waters off Goa, west coast of India (15°29‧07.6″ N to 15°34‧44.3″ N, and 73°38‧10.5″ E to 73°46‧03.1″ E) during November 2010 to May 2013. This study aimed to thoroughly understand the feeding attributes of finfishes, and comprehend the possible effects of bycatch-related loss of biomass on trophic ecology. The study assessed diet preferences of the finfishes, their feeding guilds, significance of prawns as prey items, and the influence of mouth parts in prey selection. Altogether 84 prey taxa were identified from the stomach contents. Percentage Index of Relative Importance (IRI) values revealed that zooplankton (34.74), prawns (21.71), phytoplankton (19.80), and teleosts (18.62) were the major prey categories, and, among prawns, Metapenaeus dobsoni (%IRI = 19.34) was the single-most important prey item. Cluster analysis revealed three major trophic guilds namely 'teleost feeders' (mean Trophic Level (TrL) = 4.06 ± 0.42; mean B = 0.46 ± 0.24), 'zooplankton feeders' (mean TrL = 3.43 ± 0.29; mean B = 0.23 ± 0.13), and 'prawn feeders' (mean TrL = 3.86 ± 0.25; mean B = 0.48 ± 0.32), with low diet overlap among them. Principal Component Analysis of prey categories and mouth parts of finfishes suggested that zooplanktivory is associated with gill raker density as well as number of gill arches bearing rakers, whereas gape height determined the size of large-sized prey (fish and invertebrates). The study identified M. dobsoni, mysis and teleosts as highly influential prey for predatory finfishes. The present results could be useful to resolve broader issues in fisheries management.

Biophysical processes leading to the ingress of temperate fish larvae into estuarine nursery areas: A review

Science.gov (United States)

Teodósio, Maria Alexandra; Paris, Claire B.; Wolanski, Eric; Morais, Pedro

2016-12-01

A series of complementary hypotheses have been proposed to explain the recruitment of marine and temperate pelagic fish larvae originated from pelagic eggs in coastal environments. In this review, we propose a new and complementary hypothesis describing the biophysical processes intervening in the recruitment of temperate fish larvae into estuaries. This new hypothesis, the Sense Acuity And Behavioral (SAAB) hypothesis, recognizes that recruitment is unlikely if the larvae drift passively with the water currents, and that successful recruitment requires the sense acuity of temperate fish larvae and their behavioral response to the estuarine cues present in coastal areas. We propose that temperate fish larvae use a hierarchy of sensory cues (odor, sound, visual and geomagnetic cues) to detect estuarine nursery areas and to aid during navigation towards these areas. The sensorial acuity increases along ontogeny, which coincides with increased swimming capabilities. The swimming strategies of post-flexion larvae differ from offshore areas to the tidal zone. In offshore areas, innate behavior might lead larvae towards the coast guided by a sun compass or by the earth's geomagnetic field. In areas under limited influence of estuarine plumes (either in energetic nearshore areas or offshore), post-flexion larvae display a searching swimming behavior for estuarine disconnected patches (infotaxis strategy). After finding an estuarine plume, larvae may swim along the increasing cue concentration to ingress into the estuary. Here, larvae exhibit a rheotaxis behavior and avoid displacement by longshore currents by keeping bearing during navigation. When larvae reach the vicinity of an estuary, merging diel rhythms with feeding and predator avoidance strategies with tidally induced movements is essential to increase their chances of estuarine ingress. A fish larva recruitment model developed for the Ria Formosa lagoon supports the general framework of the SAAB hypothesis. In

Revegetation Plan for Areas of the Fitzner-Eberhardt Arid Lands Ecology Reserve Affected by Decommissioning of Buildings and Infrastructure and Debris Clean-up Actions

Energy Technology Data Exchange (ETDEWEB)

Downs, Janelle L.; Durham, Robin E.; Larson, Kyle B.

2011-01-01

and specific methods for seeding and planting at each area. evegetation work is scheduled to commence during the first quarter of FY 2011 to minimize the amount of time that sites are unvegetated and more susceptible to invasion by non-native weedy annual species.

Technical feasibility of using gallery intakes for seawater RO facilities, northern Red Sea coast of Saudi Arabia: The King Abdullah Economic City site

KAUST Repository

Dehwah, Abdullah; Missimer, Thomas M.

2013-01-01

intakes. One of the potentially favorable sites for a seabed gallery system was located in the nearshore area at King Abdullah Economic City (KAEC). Detailed investigation of the site hydrology (tides and wave action), sediment grain size characteristics

Marine pollution - What are we heading for?

Digital Repository Service at National Institute of Oceanography (India)

Zingde, M.D.

Unlike the open ocean, the coastal zone is the most affected and vulnerable to human abuse with several nearshore areas including well-flushed regions and enclosed and semi-enclosed seas getting increasingly polluted. This paper examines the trends...

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Pacific Remote Island Areas from 2015-01-26 to 2015-04-28 (NCEI Accession 0162247)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

Benthic non-indigenous species among indigenous species and their habitat preferences in Puck Bay (southern Baltic Sea* This work was carried out under the ‘Ecosystem Approach to Marine Spatial Planning – Polish Marine Areas and the Natura 2000 Network’ project founded by an EEA grant from Iceland, Lichtenstein and Norway and partly by research grant BW/G 220-5-0232-9.

Directory of Open Access Journals (Sweden)

Urszula Janas

2014-06-01

Full Text Available To date 11 non-indigenous benthic taxa have been reported in Puck Bay (southern Baltic Sea. Five of the 34 taxa forming the soft bottom communities are regarded as non-indigenous to this area. They are Marenzelleria spp., Mya arenaria, Potamopyrgus antipodarum, Gammarus tigrinus and Amphibalanus improvisus. Non-indigenous species comprised up to 33% of the total number of identified macrofaunal taxa (mean 17%. The average proportion of aliens was 6% (max 46% in the total abundance of macrofauna, and 10% (max 65% in the biomass. A significant positive relationship was found between the numbers of native and non-indigenous taxa. The number of native taxa was significantly higher on a sea bed covered with vascular plants than on an unvegetated one, but no such relationship was found for their abundance. No significant differences were found in the number and abundance of non-indigenous species between sea beds devoid of vegetation and those covered with vascular plants, Chara spp. or mats of filamentous algae. G. tigrinus preferred a sea bed with vegetation, whereas Marenzelleria spp. decidedly preferred one without vegetation.

Restoration of Wadi Aquifers by Artificial Recharge with Treated Waste Water

KAUST Repository

Missimer, Thomas M.; Drewes, Jö rg E.; Amy, Gary L.; Maliva,, Robert G.; Keller, Stephanie

2012-01-01

, such as damage to sensitive nearshore marine environments and creation of high-salinity interior surface water areas. An investigation of the hydrogeology of wadi aquifers in Saudi Arabia revealed that these aquifers can be used to develop aquifer recharge

Oceans: Geochemistry and mineral resources

Digital Repository Service at National Institute of Oceanography (India)

Joao, H.M.; Paropkari, A.L.

, Indian became the first country to have been allocated exclusive rights of exploration in the pioneer area in the Central Indian Ocean Basin. Presently world wide some of the near-shore deposits are being exploited. However, the mining for other mineral...

Short-term pain for long-term gain: seagrass communities increase short-term extremes and long-term offset of CO2 under future ocean acidification

Science.gov (United States)

The impacts of ocean acidification in nearshore estuarine environments remain poorly characterized, despite these areas being some of the most ecologically, economically, and culturally important habitats in the global ocean. Here, we quantify how rising atmospheric CO2 from 1765...

Ichthyoplankton in a southern african surf zone: Nursery area for the postlarvae of estuarine associated fish species?

Science.gov (United States)

Whitfield, A. K.

1989-12-01

The surf zone ichthyoplankton of Swartvlei Bay was studied between February 1986 and June 1987, with particular emphasis on its potential role as a nursery area for estuarine associated marine fish species. Larvae and/or postlarvae of 16 families were identified from the surf zone, with the Gobiidae, Soleidae, Sparidae and Mugilidae comprising 85·7% of all teleosts sampled. The postlarvae of several taxa (including the six most common species), which utilize the Swartvlei estuary as a juvenile nursery area, were abundant in the surf zone. Conversely, species which are common in nearshore marine waters as juveniles and adults, but seldom enter estuaries, totalled less than 8% of the surf zone ichthyoplankton assemblage. Larval and postlarval densities peaked during summer when water temperatures exceeded 19°C and the estuary mouth was open. Concentrations of ichthyoplankton were highest at those sampling stations closest to the estuary mouth during the summer period. Diel changes in total catches revealed no significant difference between day and night densities; but of the four major taxa, the Mugilidae and Sparidae tended to be more abundant during the day, the Gobiidae at night and the Soleidae showed no distinct pattern. Results from a 24 h sampling session indicated that tidal phase may also be important in governing ichthyoplankton abundance in the surf zone.

MANUAL OF TEMPORARY EROSION CONTROL PRODUCTS FOR ROADSIDE DITCHES

Science.gov (United States)

2017-09-01

Sediment continues to be the primary pollutant by volume in Ohio's streams and rivers. Unvegetated roadside ditches' side slopes and bottoms erode and contribute tons of sediment annually to local receiving streams. Pollutants attach themselves to se...

Nearshore coastal bathymetry data collected in 2016 from West Ship Island to Horn Island, Gulf Islands National Seashore, Mississippi

Science.gov (United States)

DeWitt, Nancy T.; Stalk, Chelsea A.; Fredericks, Jake J.; Flocks, James G.; Kelso, Kyle W.; Farmer, Andrew S.; Tuten, Thomas M.; Buster, Noreen A.

2018-04-13

The U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center, in cooperation with the U.S. Army Corps of Engineers, Mobile District, conducted bathymetric surveys of the nearshore waters surrounding Ship and Horn Islands, Gulf Islands National Seashore, Mississippi. The objective of this study was to establish base-level elevation conditions around West Ship, East Ship, and Horn Islands and their associated active littoral system prior to restoration activities. These activities include the closure of Camille Cut and the placement of sediment in the littoral zone of East Ship Island. These surveys can be compared with future surveys to monitor sediment migration patterns post-restoration and can also be measured against historic bathymetric datasets to further our understanding of island evolution.The USGS collected 667 line-kilometers (km) of single-beam bathymetry data and 844 line-km of interferometric swath bathymetry data in July 2016 under Field Activity Number 2016-347-FA. Data are provided in three datums: (1) the International Terrestrial Reference Frame of 2000 (ellipsoid height); (2) the North American Datum of 1983 (NAD83) CORS96 realization and the North American Vertical Datum of 1988 with respect to the GEOID12B model (orthometric height); and (3) NAD83 (CORS96) and Mean Lower Low Water (tidal datum). Data products, including x,y,zpoint datasets, trackline shapefiles, digital and handwritten Field Activity Collection Systems logs, 50-meter digital elevation model, and formal Federal Geographic Data Committee metadata, are available for download.

Recolonization of the intertidal and shallow subtidal community following the 2008 eruption of Alaska's Kasatochi Volcano

Science.gov (United States)

Jewett, S. C.; Drew, G. S.

2014-03-01

The intertidal and nearshore benthic communities of Kasatochi Island are described following a catastrophic volcanic eruption in 2008. Prior to the eruption, the island was surrounded by a dense bed of canopy-forming dragon kelp Eualaria fistulosa which supported a productive nearshore community. The eruption extended the coastline of the island approximately 400 m offshore to roughly the 20 m isobath. One year following the eruption a reconnaissance survey found the intertidal zone devoid of life. Subtidally, the canopy kelp, as well as limited understory algal species and associated benthic fauna on the hard substratum, were buried by debris from the eruption. The resulting substrate was comprised almost entirely of medium and coarse sands with a depauperate benthic community. Comparisons of habitat and biological communities with other nearby Aleutian Islands and the Icelandic submarine volcanic eruption of Surtsey confirm dramatic reductions in flora and fauna consistent with the initial stages of recovery from a large-scale disturbance event. Four and five years following the eruption brief visits revealed dramatic intertidal and subtidal recolonization of the flora and fauna in some areas. Signs of nesting and fledging of young pigeon guillemots Cepphus columba suggest that the recovery of the nearshore biota may have begun affecting higher trophic levels. Recolonization or lack thereof was tied to bathymetric changes from coastal and nearshore erosion over the study period.

Recolonization of the intertidal and shallow subtidal community following the 2008 eruption of Alaska’s Kasatochi Volcano

Science.gov (United States)

Jewett, S.C.; Drew, Gary S.

2014-01-01

The intertidal and nearshore benthic communities of Kasatochi Island are described following a catastrophic volcanic eruption in 2008. Prior to the eruption, the island was surrounded by a dense bed of canopy-forming dragon kelp Eualaria fistulosa which supported a productive nearshore community. The eruption extended the coastline of the island approximately 400 m offshore to roughly the 20 m isobath. One year following the eruption a reconnaissance survey found the intertidal zone devoid of life. Subtidally, the canopy kelp, as well as limited understory algal species and associated benthic fauna on the hard substratum, were buried by debris from the eruption. The resulting substrate was comprised almost entirely of medium and coarse sands with a depauperate benthic community. Comparisons of habitat and biological communities with other nearby Aleutian Islands and the Icelandic submarine volcanic eruption of Surtsey confirm dramatic reductions in flora and fauna consistent with the initial stages of recovery from a large-scale disturbance event. Four and five years following the eruption brief visits revealed dramatic intertidal and subtidal recolonization of the flora and fauna in some areas. Signs of nesting and fledging of young pigeon guillemots Cepphus columba suggest that the recovery of the nearshore biota may have begun affecting higher trophic levels. Recolonization or lack thereof was tied to bathymetric changes from coastal and nearshore erosion over the study period.

Influence of Typhoon Matsa on Phytoplankton Chlorophyll-a off East China.

Science.gov (United States)

Zhao, Hui; Shao, Jinchao; Han, Guoqi; Yang, Dezhou; Lv, Jianhai

2015-01-01

Typhoons can cause strong disturbance, mixing, and upwelling in the upper layer of the oceans. Rich nutrients from the subsurface layer can be brought to the euphotic layer, which will induce the phytoplankton to breed and grow rapidly. In this paper, we investigate the impact of an intense and fast moving tropical storm, Typhoon Matsa, on phytoplankton chlorophyll-a (Chl-a) concentration off East China. By using satellite remote sensing data, we analyze the changes of Chl-a concentration, Sea Surface Temperature (SST) and wind speed in the pre- and post-typhoon periods. We also give a preliminary discussion on the different responses of the Chl-a concentration between nearshore and offshore waters. In nearshore/coastal regions where nutrients are generally rich, the Chl-a maximum occurs usually at the surface or at the layer close to the surface. And, in offshore tropical oligotrophic oceans, the subsurface maxima of Chl-a exist usually in the stratified water column. In an offshore area east of Taiwan, the Chl-a concentration rose gradually in about two weeks after the typhoon. However, in a coastal area north of Taiwan high Chl-a concentration decreased sharply before landfall, rebounded quickly to some degree after landfall, and restored gradually to the pre-typhoon level in about two weeks. The Chl-a concentration presented a negative correlation with the wind speed in the nearshore area during the typhoon, which is opposite to the response in the offshore waters. The phenomena may be attributable to onshore advection of low Chl-a water, coastal downwelling and intensified mixing, which together bring pre-typhoon surface Chl-a downward in the coastal area. In the offshore area, the typhoon may trigger increase of Chl-a concentration through uptake of nutrients by typhoon-induced upwelling and entrainment mixing.

Assessing diversity and phytoremediation potential of seagrass in tropical region

Science.gov (United States)

Seagrass ecosystem is one of the most important resources in the coastal areas. Seagrasses support and provide habitats for many coastal organisms in tropical region. Seagrasses are specialized marine flowering plants that have adapted to the nearshore environment with heterogeneous landscape struct...

The effect of plants on the degradation and toxicity of petroleum contaminants in soil: a field assessment.

Science.gov (United States)

Banks, M K; Schwab, P; Liu, B; Kulakow, P A; Smith, J S; Kim, R

2003-01-01

A field project located at the US Naval Base at Port Hueneme, California was designed to evaluate changes in contaminant concentrations and toxicity during phytoremediation. Vegetated plots were established in petroleum (diesel and heavy oil) contaminated soil and were evaluated over a two-year period. Plant species were chosen based on initial germination studies and included native California grasses. The toxicity of the impacted soil in vegetated and unvegetated plots was evaluated using Microtox, earthworm, and seed germination assays. The reduction of toxicity was affected more by contaminant aging than the establishment of plants. However, total petroleum hydrocarbon concentrations were lower by the end of the study in the vegetated plots when compared to the unvegetated soil. Although phytoremediation is an effective approach for cleaning-up of petroleum contaminated soil, a long-term management plan is required for significant reductions in contaminant concentrations.

Aspects of benthic decapod diversity and distribution from rocky nearshore habitat at geographically widely dispersed sites.

Directory of Open Access Journals (Sweden)

Gerhard Pohle

Full Text Available Relationships of diversity, distribution and abundance of benthic decapods in intertidal and shallow subtidal waters to 10 m depth are explored based on data obtained using a standardized protocol of globally-distributed samples. Results indicate that decapod species richness overall is low within the nearshore, typically ranging from one to six taxa per site (mean = 4.5. Regionally the Gulf of Alaska decapod crustacean community structure was distinguishable by depth, multivariate analysis indicating increasing change with depth, where assemblages of the high and mid tide, low tide and 1 m, and 5 and 10 m strata formed three distinct groups. Univariate analysis showed species richness increasing from the high intertidal zone to 1 m subtidally, with distinct depth preferences among the 23 species. A similar depth trend but with peak richness at 5 m was observed when all global data were combined. Analysis of latitudinal trends, confined by data limitations, was equivocal on a global scale. While significant latitudinal differences existed in community structure among ecoregions, a semi-linear trend in changing community structure from the Arctic to lower latitudes did not hold when including tropical results. Among boreal regions the Canadian Atlantic was relatively species poor compared to the Gulf of Alaska, whereas the Caribbean and Sea of Japan appeared to be species hot spots. While species poor, samples from the Canadian Atlantic were the most diverse at the higher infraordinal level. Linking 11 environmental variables available for all sites to the best fit family-based biotic pattern showed a significant relationship, with the single best explanatory variable being the level of organic pollution and the best combination overall being organic pollution and primary productivity. While data limitations restrict conclusions in a global context, results are seen as a first-cut contribution useful in generating discussion and more in

Public environmental impact assessment in planning process of the near-shore wind power farms in Estonia. Avalikkuse osalemine keskkonnamõju hindamise ja planeerimisprotsessis rannikumere tuuleparkide näitel Eestis

Directory of Open Access Journals (Sweden)

Karin Lindroos

2016-08-01

Full Text Available This paper examines the nature and opportunities of public participation in the environmental impact assessment (EIA and planning processes in the context of massive expansion of near-shore wind power farms within the next decade in Estonia. The establishment of new wind farms has aroused opposition of the local population as in many other countries. In the present case, we focus on the wind park planned in the sea between Hiiumaa and Saaremaa (Soela Strait, in respect to which we conducted a case study of stakeholders in spring-summer 2014. Purpose of the research is to understand and assess the development of the surroundings in which people live and transformation in connection with the wind park planning, and institutional and individual attitudes and strategies in the processes of informing, involvement, participation and decision-making. The analysis of attitudes is based on social impact assessment: aesthetical, socio-economic and cultural tendencies

33 CFR 155.1020 - Definitions.

Science.gov (United States)

2010-07-01

... boundary lines defined in 46 CFR part 7, except that in the Gulf of Mexico, it means the area shoreward of... lines defined in 46 CFR part 7, except in the Gulf of Mexico. In the Gulf of Mexico, a nearshore area is... Certificate of Documentation has been issued in the name of a president or secretary of an incorporated...

Title: Gully Erosion Mapping Using Remote Sensing Techniques in ...

African Journals Online (AJOL)

NdifelaniM

results indicated a user's accuracy of 98.67% and 54% for non-gully and gully class .... for gully class and 150 for non-gully class) were generated using ERDAS ... soil (un-vegetated gully) is dependent on the moisture content, organic matter.

ENVIRONMENTAL EFFECTS OF A GOLF COMPLEX ON COASTAL WETLANDS IN THE GULF OF MEXICO

Science.gov (United States)

The increasing density of golf courses represents a potential source of contamination to nearby coastal wetlands and other near-shore areas. The chemical and biological magnitude of the problem is almost unknown. To provide perspective on this issue, the effects of golf complex r...

Tracing multi-habitat support of coastal fishes

Science.gov (United States)

Hydrologic linkages among coastal wetland and nearshore areas allow coastal fish to move among the habitats, which has led to a variety of habitat use patterns. In the Great Lakes, fine-scale microchemical analyses of yellow perch otoliths have revealed life-history categories th...

Disjoint geographical distribution of intertidal and nearshore benthic invertebrates in the Southern Hemisphere Distribuciones geográficas disyuntas de invertebrados bentónicos intermareales y del submareal somero en el Hemisferio Sur

Directory of Open Access Journals (Sweden)

JUAN C CASTILLA

2000-12-01

Full Text Available Biogeographical explanations for the extant and paleo disjoint geographical distribution in the southern hemisphere of five species of nearshore marine benthic invertebrates: Gaimardia trapesina, Ostrea chilensis, Pyura stolonifera taxonomic complex, Aulacomya ater and Concholepas concholepas, showing distinctive reproductive strategies and early life history characteristics are reviewed and analyzed. Through the use of published and new information we contrasted the following hypotheses: a vicariance-historical process, b epiplanktonic larval dispersal, c juvenile/adult dispersal through rafting and d planned or accidental anthropogenic dispersal mechanisms. The juvenile/adult transoceanic dispersal hypothesis by rafting was the only one impossible to be rejected for the species analyzed. The implication and future direction for research in this area are discussedSe revisa y analiza las posibles explicaciones para la distribución geográfica disyunta, presente y pasada, en el hemisferio sur de cinco especies de invertebrados bentónicos marinos litorales: Gaimardia trapesina, Ostrea chilensis, el complejo taxonómico Pyura stolonifera, Aulacomya ater y Concholepas concholepas, con estrategias reproductivas y características de historia de vida distintas. Se discute y pone a prueba, usando información original o publicada, las siguientes hipótesis: a procesos históricos de vicarianza, b dispersión de larvas epi-planctónicas, c dispersión de juveniles o adultos por transporte pasivo y d dispersión antropogénica planificada o accidental. La hipótesis de dispersión transoceánica de juveniles o adultos fue la única imposible de rechazar para las especies analizadas. Se discute las direcciones futuras de investigación en esta área

Effect of soil organic matter on antimony bioavailability after the remediation process

International Nuclear Information System (INIS)

Nakamaru, Yasuo Mitsui; Martín Peinado, Francisco José

2017-01-01

We evaluated the long-term (18 year) and short-term (4 weeks) changes of Sb in contaminated soil with SOM increase under remediation process. In the Aznalcóllar mine accident (1998) contaminated area, the remediation measurement implemented the Guadiamar Green Corridor, where residual pollution is still detected. Soils of the re-vegetated area (O2) with high pH and high SOM content, moderately re-vegetated area (O1) and unvegetated area (C) were sampled. Soil pH, CEC, SOM amount and soil Sb forms were evaluated. Soil Sb was measured as total, soluble, exchangeable, EDTA extractable, acid oxalate extractable, and pyro-phosphate extractable fractions. Further, the short-term effect of artificial organic matter addition was also evaluated with incubation study by adding compost to the sampled soil from C, O1 and O2 areas. After 4 weeks of incubation, soil chemical properties and Sb forms were evaluated. In re-vegetated area (O2), soil total Sb was two times lower than in unvegetated area (C); however, soluble, exchangeable, and EDTA extractable Sb were 2–8 times higher. The mobile/bioavailable Sb increase was also observed after 4 weeks of incubation with the addition of compost. Soluble, exchangeable, and EDTA extractable Sb was increased 2–4 times by compost addition. By the linear regression analysis, the significantly related factors for soluble, exchangeable, and EDTA extractable Sb values were pH, CEC, and SOM, respectively. Soluble Sb increase was mainly related to pH rise. Exchangeable Sb should be bound by SOM-metal complex and increased with CEC. EDTA extractable fraction should be increased with increase of SOM as SOM-Fe associated Sb complex. From these results, it was shown that increase of SOM under natural conditions or application of organic amendment under remediation process should increase availability of Sb to plants. - Highlights: • The effect of SOM on Sb availability was evaluated after the remediation process. • Increase in SOM raised

Organic carbon content of zooplankton from the nearshore waters of Bombay

Digital Repository Service at National Institute of Oceanography (India)

Nair, V.R.; Gajbhiye, S.N.; Sayed, F.Y.

Organic carbon content of zooplankton in the Versova Creek and Thana Creek (polluted areas), off Versova and off Mahim, Bombay, India (relatively unpolluted areas) varied respectively from 21.4-30, 13.2-38.4, 21.6-30 and 25.8-39.6% dry weight...

Comparison of two methods for estimating the abundance, diversity and habitat preference of fluvial macroinvertebrates in contrasting habitats

NARCIS (Netherlands)

Alonso, A.; Camargo, J.A.

2010-01-01

In this research we evaluate the effects of the method used for estimating the potential surface available for benthic macroinvertebrates in macrophyte and unvegetated habitats on several metrics and habitat preference of aquatic macroinvertebrates in the upper catchment of the Henares River

Migration redefined? Seasonality, movements and group ...

African Journals Online (AJOL)

The migration of Southern Hemisphere humpback whales Megaptera novaeangliae between their feeding and breeding areas has thus far been considered a highly predictable and seasonal event. However, previous observations on the humpbacks that pass through the nearshore waters of the west coast of South Africa ...

Experimental study of sediment fluxes on Barcelona's nearshore

OpenAIRE

Armengou Gallardo, Carla

2011-01-01

The presence of suspended sediment in marine waters has several impacts, such as a degradation of the coastal ecosystem, pollution or a damaging effect on the tourism-oriented economies. FIELD_AC is a European project that aims to provide an improved operational service for coastal areas and generate added value for GMES predictions. This is achieved by the analysis of field cases. In this context, this minor thesis is based on the study of the information obtained in a field campaign car...

Toxicity of dispersant application: Biomarkers responses in gills of juvenile golden grey mullet (Liza aurata).

Science.gov (United States)

Milinkovitch, Thomas; Godefroy, Joachim; Théron, Michaël; Thomas-Guyon, Hélène

2011-10-01

Dispersant use in nearshore areas is likely to increase the exposure of aquatic organisms to petroleum. To measure the toxicity of this controversial response technique, golden grey mullets (Liza aurata) were exposed to mechanically dispersed oil, chemically dispersed oil, dispersant alone in seawater, water-soluble fraction of oil and to seawater as a control treatment. Several biomarkers were assessed in the gills (enzymatic antioxidant activities, glutathione content, lipid peroxidation) and in the gallbladder (polycylic aromatic hydrocarbons metabolites). The significant differences between chemically dispersed oil and water soluble fraction of oil highlight the environmental risk to disperse an oil slick when containment and recovery can be conducted. The lack of significance between chemically and mechanically dispersed oil suggests that dispersant application is no more toxic than the natural dispersion of the oil slick. The results of this study are of interest in order to establish dispersant use policies in nearshore areas. Copyright © 2011 Elsevier Ltd. All rights reserved.

Complexity of nearshore strontium-to-calcium ratio variability in a core sample of the massive coral Siderastrea siderea obtained in Coral Bay, St. John, U.S. Virgin Islands

Science.gov (United States)

Reich, Christopher D.; Kuffner, Ilsa B.; Hickey, T. Don; Morrison, Jennifer M.; Flannery, Jennifer A.

2013-01-01

Strontium-to-calcium ratios (Sr/Ca) were measured on the skeletal matrix of a core sample from a colony of the massive coral Siderastrea siderea collected in Coral Bay, St. John, U.S. Virgin Islands. Strontium and calcium are incorporated into the coral skeleton during the precipitation of aragonite by the coral polyps and their ratio is highly temperature dependent. The robustness of this temperature dependence makes Sr/Ca a reliable proxy for sea surface temperature (SST). Details presented from the St. John S. siderea core indicate that terrestrial inputs of sediment and freshwater can disrupt the chemical balance and subsequently complicate the utility of Sr/Ca in reconstructing historical SST. An approximately 44-year-long record of Sr/Ca shows that an annual SST signal is recorded but with an increasing Sr/Ca trend from 1980 to present, which is likely the result of runoff from the mountainous terrain of St. John. The overwhelming influence of the terrestrial fingerprint on local seawater chemistry makes utilizing Sr/Ca as a SST proxy in nearshore environments very difficult.

Statistical analysis of lake levels and field study of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015: Chapter A of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

Science.gov (United States)

Jones, Perry M.; Trost, Jared J.; Diekoff, Aliesha L.; Rosenberry, Donald O.; White, Eric A.; Erickson, Melinda L.; Morel, Daniel L.; Heck, Jessica M.

2016-10-19

Water levels declined from 2003 to 2011 in many lakes in Ramsey and Washington Counties in the northeast Twin Cities Metropolitan Area, Minnesota; however, water levels in other northeast Twin Cities Metropolitan Area lakes increased during the same period. Groundwater and surface-water exchanges can be important in determining lake levels where these exchanges are an important component of the water budget of a lake. An understanding of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area has been limited by the lack of hydrologic data. The U.S. Geological Survey, in cooperation with the Metropolitan Council and Minnesota Department of Health, completed a field and statistical study assessing lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes. This report documents the analysis of collected hydrologic, water-quality, and geophysical data; and existing hydrologic and geologic data to (1) assess the effect of physical setting and climate on lake-level fluctuations of selected lakes, (2) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (3) estimate general ages for waters extracted from the wells, and (4) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake. Statistical analyses of lake levels during short-term (2002–10) and long-term (1925–2014) periods were completed to help understand lake-level changes across the northeast Twin Cities Metropolitan Area. Comparison of 2002–10 lake levels to several landscape and geologic characteristics explained variability in lake-level changes for 96 northeast Twin Cities Metropolitan Area lakes. Application of several statistical methods determined that (1) closed-basin lakes (without an active outlet) had larger lake-level declines than flow-through lakes with an outlet; (2

Primary productivity in nearshore waters of Thal, Maharashtra coast

Digital Repository Service at National Institute of Oceanography (India)

Varshney, P.K.; Nair, V.R.; Abidi, S.A.H.

Primary productivity off Thal, Maharashtra, India was evaluated at 3 stations during Feb. 1980 to Jan. 1981. The area was quite turbid and the euphotic zone never exceeded 2.5 m. Column production ranged from 0.69 to 605.21 mg C.m/2.d/2 (av. 78.2 mg...

Hg, Pb and Cd in zooplankton from an area of the Adriatic opposite the Romagna coast line

Energy Technology Data Exchange (ETDEWEB)

Crisetig, G; Cattani, O; Massa, D; Poletti, R

1982-09-15

The concentrations of heavy metals Hg, Pb and Cd found in zooplankton samples collected in two stations off Cesenatico (Northern Adriatic Sea) from March 1978 to January 1979, have been reported. The Hg, Pb and Cd concentrations showed large variations which did not seem to be correlated with taxonomic composition. The detected levels of metals were higher at the offshore than the nearshore station, accordingly with the sediment pattern. The high concentration of Hg were apparently associated with sources of local industrial pollution.

33 CFR 155.2230 - Response plan development and evaluation criteria.

Science.gov (United States)

2010-07-01

... HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR... and canals, inland, nearshore, and offshore areas 24 hrs N/A N/A Open ocean (plus travel time from... hours. (iii) Open ocean waters—36 hours. (3) For barges operating in rivers and canals as defined in...

78 FR 56659 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a...

Science.gov (United States)

2013-09-13

..., Excel, or Adobe PDF file formats only. FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected... requires notice and opportunity for public comment. NMFS has defined ``negligible impact'' in 50 CFR 216..., as well as greater immigration of animals into the nearshore study area (DFO, 2009). The rapid growth...

Analysis of groundwater response to tidal fluctuations, Operable Unit 2, Area 8, Naval Base Kitsap, Keyport, Washington

Science.gov (United States)

Opatz, Chad C.; Dinicola, Richard S.

2018-05-21

Operable Unit 2, Area 8, at Naval Base Kitsap, Keyport is the site of a former chrome-plating facility that released metals (primarily chromium and cadmium), chlorinated volatile organic compounds, and petroleum compounds into the local environment. To ensure long-term protectiveness, as stipulated in the Fourth Five-Year Review for the site, Naval Facilities Engineering Command Northwest collaborated with the U.S. Environmental Protection Agency, the Washington State Department of Ecology, and the Suquamish Tribe, to collect data to monitor the contamination left in place and to ensure the site does not pose a risk to human health or the environment. To support these efforts, refined information was needed on the interaction of fresh groundwater with seawater in response to the up-to 13-ft tidal fluctuations at this nearshore site adjacent to Port Orchard Bay. The information was analyzed to meet the primary objective of this investigation, which was to determine the optimal time during the semi-diurnal and the neap-spring tidal cycles to sample groundwater for freshwater contaminants in Area 8 monitoring wells.Groundwater levels and specific conductance in five monitoring wells, along with marine water-levels (tidal levels) in Port Orchard Bay, were monitored every 15 minutes during a 3-week duration to determine how nearshore groundwater responds to tidal forcing. Time series data were collected from October 24, 2017, to November 16, 2017, a period that included neap and spring tides. Vertical profiles of specific conductance were also measured once in the screened interval of each well prior to instrument deployment to determine if a freshwater/saltwater interface was present in the well during that particular time.The vertical profiles of specific conductance were measured only one time during an ebbing tide at approximately the top, middle, and bottom of the saturated thickness within the screened interval of each well. The landward-most well, MW8-8, was

Paleoecological Evidence for Late Holocene Range Shifting of Acropora palmata and Orbicella annularis on the Nearshore Southeast Florida Reef Tract

Science.gov (United States)

Modys, A. B.; Zuccarelli, C. L.; Oleinik, A. E.

2016-02-01

Climate fluctuations on the southeast Florida reef tract have been linked to long-term geographic distribution shifts in framework-building coral species Acropora palmata and Orbicella annularis. Previous data suggest that the boundary for active reef accretion driven by these corals contracted southward to its current position at Biscayne Bay throughout the early to middle Holocene ( 8500-5500 cal BP). However, recent observations have shown that while A. palmata and O. annularis are still functionally absent north of this boundary, they are well represented within late Holocene sub-fossil death assemblages found at 3-4 m depths on the nearshore ridge complex (NRC). To assess this disparity, we performed a systematic comparison of taxonomic composition and diversity of living and dead coral assemblages at two locations on the northern NRC. We also determined an estimated age range for the death assemblages from 2 samples of A. palmata and 1 sample of O. annularis using high-resolution AMS radiocarbon dating. Our results show a clear transition from a late Holocene reef assemblage dominated by A. palmata and O. annularis to a modern reef assemblage dominated by less sensitive Porites astreoides. Sub-fossil A. palmata samples dated to 2950-3140 cal BP and 1820-1960 cal BP (2σ), and the sub-fossil O. annularis sample dated to 2290-2420 cal BP (2σ), indicating a total growth period of at least 1000 years. Our findings provide new evidence for a distinct late Holocene range shift in A. palmata and O. annularis on the northern shallow-water ridge complex of the southeast Florida reef tract system.

The complex early life history of a marine estuarine-opportunist fish species, Solea turbynei (Soleidae from temperate South Africa

Directory of Open Access Journals (Sweden)

Nadine A. Strydom

2015-06-01

Full Text Available The early life history stages and ecology of Solea turbynei, a marine estuarine-opportunist species, is described from nursery areas in Algoa Bay, South Africa. Early life history stages were collected over multiple years from known nursery habitats using plankton, fyke and larval seine nets. The larvae are described using morphometric measurements, meristic counts and pigmentation based on 29 individuals. Solea turbynei is differentiated from other Soleidae by the small size at flexion (3-4 mm, low myomere count and presence of two characteristic blotches of pigment on the dorsal fin. This species has a unique early life history strategy in that the larvae progressively span nearshore, surf zone and estuarine habitats with ontogeny. Abundance of preflexion stages peaks in summer in nearshore waters, indicative of peak spawning period but preflexion larvae are present throughout the year, indicating protracted spawning by adults. At flexion stage, larvae utilize surf zones where metamorphosis and settlement takes place. Early juveniles migrate into the sandy lower reaches of estuaries, after which fish take up residency to adulthood. Warm water is important for larval growth and survival in the nearshore, while turbidity shows a positive relationship with recruitment into estuarine nurseries.

Extreme water level and wave estimation for nearshore of Ningde City

Science.gov (United States)

Jin, Y. D.; Wang, E. K.; Xu, G. Q.

2017-08-01

The high and low design water levels are calculated by observation tidal data in sea areas of Ningde offshore wind power project from September 2010 to August 2011, with the value 318 cm and -246 cm, respectively. The extreme high and low levels are also calculated using synchronous difference ratio method based on station data from 1973 to 2005 at Sansha station. The value is 431 cm and -378 cm respectively. The design wave elements are estimated using the wave data from Beishuang Station and Pingtan station. On this basis, the SWAN wave model is applied to calculating the design wave elements in the engineering sea areas. The results show that the southern sea area is mainly affected by the wave effect on ESE, and the northern is mainly affected by the E waves. This paper is helpful and useful for design and construction of offshore and coastal engineering.

White shark and other chondrichthyan interactions with the beach ...

African Journals Online (AJOL)

Public perception has been that an apparent increase in the nearshore occurrence of white sharks Carcharodon carcharias in False Bay, on the south coast of South Africa, can at least be partly attributed to beach-seine (treknet) operations attracting sharks into this coastal area. To assess the merit of these concerns, ...

The influence of current speed and vegetation density on flow structure in two macrotidal eelgrass canopies

Science.gov (United States)

Lacy, Jessica R.; Wyllie-Echeverria, Sandy

2011-01-01

The influence of eelgrass (Zostera marina) on near-bed currents, turbulence, and drag was investigated at three sites in two eelgrass canopies of differing density and at one unvegetated site in the San Juan archipelago of Puget Sound, Washington, USA. Eelgrass blade length exceeded 1 m. Velocity profiles up to 1.5 m above the sea floor were collected over a spring-neap tidal cycle with a downward-looking pulse-coherent acoustic Doppler profiler above the canopies and two acoustic Doppler velocimeters within the canopies. The eelgrass attenuated currents by a minimum of 40%, and by more than 70% at the most densely vegetated site. Attenuation decreased with increasing current speed. The data were compared to the shear-layer model of vegetated flows and the displaced logarithmic model. Velocity profiles outside the meadows were logarithmic. Within the canopies, most profiles were consistent with the shear-layer model, with a logarithmic layer above the canopy. However, at the less-dense sites, when currents were strong, shear at the sea floor and above the canopy was significant relative to shear at the top of the canopy, and the velocity profiles more closely resembled those in a rough-wall boundary layer. Turbulence was strong at the canopy top and decreased with height. Friction velocity at the canopy top was 1.5–2 times greater than at the unvegetated, sandy site. The coefficient of drag CD on the overlying flow derived from the logarithmic velocity profile above the canopy, was 3–8 times greater than at the unvegetated site (0.01–0.023 vs. 2.9 × 10−3).

A hierarchical classification of benthic biodiversity and assessment of protected areas in the Southern Ocean.

Directory of Open Access Journals (Sweden)

Lucinda L Douglass

Full Text Available An international effort is underway to establish a representative system of marine protected areas (MPAs in the Southern Ocean to help provide for the long-term conservation of marine biodiversity in the region. Important to this undertaking is knowledge of the distribution of benthic assemblages. Here, our aim is to identify the areas where benthic marine assemblages are likely to differ from each other in the Southern Ocean including near-shore Antarctica. We achieve this by using a hierarchical spatial classification of ecoregions, bathomes and environmental types. Ecoregions are defined according to available data on biogeographic patterns and environmental drivers on dispersal. Bathomes are identified according to depth strata defined by species distributions. Environmental types are uniquely classified according to the geomorphic features found within the bathomes in each ecoregion. We identified 23 ecoregions and nine bathomes. From a set of 28 types of geomorphic features of the seabed, 562 unique environmental types were classified for the Southern Ocean. We applied the environmental types as surrogates of different assemblages of biodiversity to assess the representativeness of existing MPAs. We found that 12 ecoregions are not represented in MPAs and that no ecoregion has their full range of environmental types represented in MPAs. Current MPA planning processes, if implemented, will substantially increase the representation of environmental types particularly within 8 ecoregions. To meet internationally agreed conservation goals, additional MPAs will be needed. To assist with this process, we identified 107 spatially restricted environmental types, which should be considered for inclusion in future MPAs. Detailed supplementary data including a spatial dataset are provided.

2013 status of the Lake Ontario lower trophic levels

Science.gov (United States)

Holeck, Kristen T.; Rudstam, Lars G.; Hotaling, Christopher; McCullough, Russ D.; Lemon, Dave; Pearsall, Web; Lantry, Jana R.; Connerton, Michael J.; LaPan, Steve; Trometer, Betsy; Lantry, Brian F.; Walsh, Maureen; Weidel, Brian C.

2014-01-01

Phosphorus showed high variation across nearshore (10 m depth) sites but was more stable at offshore (20 m and deeper) stations. In June and July, sites at the mouth of the Niagara River and at Oak Orchard had high phosphorus concentrations (20 – 46 μg/L). Epilimnetic average April-Oct total phosphorus (TP) ranged between 6.9 and 19.9 μg/L in the nearshore and between 5.8 and 10.2 μg/L in the offshore. Average April-Oct soluble reactive phosphorus (SRP) ranged from 0.9 to 7.3 μg/L in the nearshore and 0.8 to 1.4 μg/L in the offshore. TP and SRP were significantly higher in the nearshore than in the offshore.Spring TP has declined in the longer data series (since 1981), but not since 1995. It averaged 8.4 μg/L in the nearshore and 5.0 μg/L in the offshore in 2013—below the 10 μg/L target set by the Great Lakes Water Quality Agreement of 1978 for offshore waters of Lake Ontario.Offshore summer chlorophyll-a declined significantly in both the short- (1995-2013) and long-term (1981-2013) time series at a rate of 3-4% per year. Nearshore chlorophyll-a increased after 2003 but then declined again after 2009. Epilimnetic chlorophyll-aaveraged between 0.5 and 1.3 μg/L across sites with no difference between nearshore and offshore habitats. Average seasonal Secchi disk depth ranged from 4.5 m to 10.6 m and was higher in the offshore (average 8.1 m) than nearshore stations (6.3 m). These values are indicative of oligotrophic conditions in both habitats.In 2013, Apr/May - Oct epilimnetic zooplankton size and total biomass were significantly higher in the offshore than the nearshore. However, with the exception of Limnocalanus (higher in offshore), there were no differences between habitats for any of the zooplankton groups.Most of the zooplankton biomass was in the metalimnion and hypolimnion during the day in 2013. Between 65 and 98% of zooplankton biomass was found below the thermocline throughout the year.The predatory cladoceran Cercopagis continued to be

Factorial study of rain garden design for nitrogen removal

Science.gov (United States)

Abstract Nitrate (〖NO〗_3^--N ) removal studies in bioretention systems showed great variability in removal rates and in some cases 〖NO〗_3^--N was exported. A 3-way factorial design (2 x 2 x 4) was devised for eight outdoor un-vegetated rain gardens to evaluate the effects of ...

Geologic characterization of shelf areas using usSEABED for GIS mapping, modeling processes and assessing marine sand and gravel resources

Science.gov (United States)

Williams, S.J.; Bliss, J.D.; Arsenault, M.A.; Jenkins, C.J.; Goff, J.A.

2007-01-01

Geologic maps depicting offshore sedimentary features serve many scientific and applied purposes. Such maps have been lacking, but recent computer technology and software offer promise in the capture and display of diverse marine data. Continental margins contain landforms which provide a variety of important functions and contain important sedimentary records. Some shelf areas also contain deposits regarded as potential aggregate resources. Because proper management of coastal and offshore areas is increasingly important, knowledge of the framework geology and marine processes is critical. Especially valuable are comprehensive and integrated digital databases based on high-quality information from original sources. Products of interest are GIS maps containing thematic information, such as sediment character and texture. These products are useful to scientists modeling nearshore and shelf processes as well as planners and managers. The U.S. Geological Survey is leading a national program to gather a variety of extant marine geologic data into the usSEABED database system. This provides centralized, integrated marine geologic data collected over the past 50 years. To date, over 340,000 sediment data points from the U.S. reside in usSEABED, which combines an array of physical data and analytical and descriptive information about the sea floor and are available to the marine community through three USGS data reports for the Atlantic, Gulf of Mexico, and Pacific published in 2006, and the project web sites: (http://woodshole.er.usg s.gov/project-pages/aggregates/ and http://walrus.wr.usgs.gov/usseabed/)

Use of a fishery-independent trawl survey to evaluate distribution patterns of subadult sharks in Georgia

Science.gov (United States)

Belcher, C.N.; Jennings, Cecil A.

2009-01-01

We investigated the utility of a fishery-independent trawl survey for assessing a potential multispecies shark nursery in Georgia's nearshore and inshore waters. A total of 234 subadult sharks from six species were captured during 85 of 216 trawls. Catch rates and size distributions for subadult sharks and the ratio of neonates to juveniles were consistent among areas. The highest concentrations of subadult sharks occurred in creeks and sounds. Species composition varied among areas. The Atlantic sharpnose shark Rhizoprionodon terraenovae was the most abundant species in sound and nearshore stations, whereas the bonnethead Sphyrna tiburo was the most abundant species in creeks. The aggregate of other species occurred with higher frequency in the sounds and nearshore. Sampling characteristics of the trawl survey were compared with those from a fishery-independent longline survey of subadult sharks to assess the similarity of the two gears. A total of 193 subadult sharks from seven species were captured during 57 of 96 longline sets, whereas 52 subadults from four species were captured during 20 of 48 trawls. Selectivity and efficiency differed between the two gears. The trawl had lower catch rates, caught smaller sharks, and encountered a different suite of species than the longline. General seasonal trends in relative abundance also differed between the two gears; the longline showed an increasing trend in abundance, whereas the trawl showed a stable trend. Although trawls were not found to be efficient for sampling subadult sharks from most species, they can be a useful source of supplemental data.

BOTTOM SEDIMENTS IN DELTAIC SHALLOW-WATER AREAS – ARE THEY SOILS?

Directory of Open Access Journals (Sweden)

Anna N. Tkachenko

2016-01-01

Full Text Available This article is based on long-term research of aquatic landscapes in the VolgaRiver delta which was held in 2010–2012 and included investigation and sampling of bottom sediments in deltaic lagoons, fresh-water bays, small channels, oxbow lakes, and part of the deltaic near-shore zone. Contrasting hydrological regime and suspended matter deposition together with huge amount of water plants in the river delta provide for the formation of different types of subaquatic soils. The purpose of this research is to reveal the properties of the subaquatic soils in the Volga River deltaic area and to propose pedogenetic approaches to the diagnostic of aquazems as soil types. It is suggested to name the horizons in aquazems in the same way as in terrestrial soils in the recent Russian soil classification system, and apply symbols starting with the combination of caps – AQ (for “aquatic”. The aquazems’ horizons are identified and their general properties are described. Most typical of aquazems is the aquagley (AQG horizon; it is dove grey, homogeneous in color and permeated by clay. The upper part is usually enriched in organic matter and may be qualified for aquahumus (AQA or  aquapeat (AQT horizons. In case of active hydrodynamic regime and/or strong mixing phenomena, the oxidized (AQOX or aqox horizon, or property could be formed. It is yellowish-grey, thin, and depleted of organic matter. The main types of aquzems specified by forming agents and combinations of horizons are described.

The use of 234Th/238U disequilibrium to examine the fate of particle-reactive species on the Yangtze continental shelf

International Nuclear Information System (INIS)

McKee, B.A.; DeMaster, D.J.; Nittrouer, C.A.

1984-01-01

Measurements of 234 Th (tsub(1/2)=24.1 d) in water column and seabed samples from an area near the mouth of the Yangtze River (People's Republic of China) provide the following information: Most of the 234 Th in waters near the mouth of the Yangtze River is in particulate form, and horizontal transport and sedimentation of 234 Th-bearing particles dominate the 234 Th budget in this area. A model incorporating processes in at least two dimensions is required to understand the fate of particle-reactive species on the Yangtze continental shelf. The residence times of particle-reactive species (with respect to scavenging) range from 0.3 days (nearshore) to 4.0 days (offshore). The residence times (with respect to removal to the seabed) range from 0.5 day (nearshore) to 11.0 days (offshore). Scavenging residence times for 234 Th decrease as the concentration of suspended particles increases. The time for removal of 234 Th to the seabed increases with distance from shore (a variable which integrates such factors as scavenging rate, bathymetry, and frequency of resuspension). (orig.)

State of the Art and Challenges for Offshore Integrated Multi-Trophic Aquaculture (IMTA

Directory of Open Access Journals (Sweden)

Bela H. Buck

2018-05-01

Full Text Available By moving away from coastal waters and hence reducing pressure on nearshore ecosystems, offshore aquaculture can be seen as a possible step towards the large-scale expansion of marine food production. Integrated multi-trophic aquaculture (IMTA in nearshore water bodies has received increasing attention and could therefore play a role in the transfer of aquaculture operations to offshore areas. IMTA holds scope for multi-use of offshore areas and can bring environmental benefits from making use of waste products and transforming these into valuable co-products. Furthermore, they may act as alternative marine production systems and provide scope for alternative income options for coastal communities, e.g., by acting as nodes for farm operation and maintenance requirements. This paper summarizes the current state of knowledge on the implications of the exposed nature of offshore and open ocean sites on the biological, technological and socio-economic performance of IMTA. Of particular interest is improving knowledge about resource flows between integrated species in hydrodynamic challenging conditions that characterize offshore waters.

Nearshore currents along the Karnataka coast, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

SanilKumar, V.; Dora, G.U.; Philip, C.S.; Pednekar, P.S.; Singh, J.

(Kalney et.al., 1996) was obtained for the point (12.5º N; 72.5 º E) close to the study area to know the influence of wind on sea level and currents. These data are provided by the NOAA-CIRES Climate Diagnostics Center, Boulder, Colarado at http://www.cdc...

Nearshore circulation and water-column properties in the Skagit River Delta, northern Puget Sound, Washington: juvenile Chinook Salmon habitat availability in the Swinomish Channel

Science.gov (United States)

Grossman, Eric E.; Stevens, Andrew W.; Gelfenbaum, Guy; Curran, Christopher

2007-01-01

Time-series and spatial measurements of nearshore hydrodynamic processes and water properties were made in the Swinomish Channel to quantify the net direction and rates of surface water transport that influence habitat for juvenile Chinook salmon along their primary migratory corridor between the Skagit River and Padilla Bay in northern Puget Sound, Washington. During the spring outmigration of Skagit River Chinook between March and June 2007, currents measured with fixed acoustic doppler current profilers (ADCP) at the south and north end of the Swinomish Channel and with roving ADCP revealed that the currents are highly asymmetric with a dominant flow to the north (toward Padilla Bay). Maximum surface current velocities reached 1.5 m/s and were generally uniform across the channel near McGlinn Island Causeway. Transport times for surface water to travel the 11 km from the southern end of Swinomish Channel at McGlinn Island to Padilla Bay ranged from 2.1 hours to 5.5 days. The mean travel time was ~1 day, while 17 percent of the time, transport of water and passive particles occurred within 3.75 hours. Surface water in the Swinomish Channel during this time was generally very saline 20-27 psu, except south of the Rainbow Bridge in the town of La Conner where it ranged 0-15 psu depending on tide and Skagit River discharge. This salinity regime restricts suitable low salinity (

Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna

Science.gov (United States)

Borrell Pichs, Yaisel J.; García-Vazquez, Eva

2018-01-01

Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse

Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna.

Directory of Open Access Journals (Sweden)

Sabine Rech

Full Text Available Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas and the Australian barnacle (Austrominius modestus. The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a

Anthropogenic marine litter composition in coastal areas may be a predictor of potentially invasive rafting fauna.

Science.gov (United States)

Rech, Sabine; Borrell Pichs, Yaisel J; García-Vazquez, Eva

2018-01-01

Anthropogenic plastic pollution is a global problem. In the marine environment, one of its less studied effects is the transport of attached biota, which might lead to introductions of non-native species in new areas or aid in habitat expansions of invasive species. The goal of the present work was to assess if the material composition of beached anthropogenic litter is indicative of the rafting fauna in a coastal area and could thus be used as a simple and cost-efficient tool for risk assessment in the future. Beached anthropogenic litter and attached biota along the 200 km coastline of Asturias, central Bay of Biscay, Spain, were analysed. The macrobiotic community attached to fouled litter items was identified using genetic barcoding combined with visual taxonomic analysis, and compared between hard plastics, foams, other plastics and non-plastic items. On the other hand, the material composition of beached litter was analysed in a standardized area on each beach. From these two datasets, the expected frequency of several rafting taxa was calculated for the coastal area and compared to the actually observed frequencies. The results showed that plastics were the most abundant type of beached litter. Litter accumulation was likely driven by coastal sources (industry, ports) and river/sewage inputs and transported by near-shore currents. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to fishing activity and leisure/ household. We identified a variety of rafting biota, including species of goose barnacles, acorn barnacles, bivalves, gastropods, polychaetes and bryozoan, and hydrozoan colonies attached to stranded litter. Several of these species were non-native and invasive, such as the giant Pacific oyster (Crassostrea gigas) and the Australian barnacle (Austrominius modestus). The composition of attached fauna varied strongly between litter items of different materials. Plastics, except for foam, had a much more diverse

Application of RAD-BCG calculator to Hanford's 300 area shoreline characterization dataset

Energy Technology Data Exchange (ETDEWEB)

Antonio, Ernest J.; Poston, Ted M.; Tiller, Brett L.; Patton, Gene W.

2003-07-01

Abstract. In 2001, a multi-agency study was conducted to characterize potential environmental effects from radiological and chemical contaminants on the near-shore environment of the Columbia River at the 300 Area of the U.S. Department of Energy’s Hanford Site. Historically, the 300 Area was the location of nuclear fuel fabrication and was the main location for research and development activities from the 1940s until the late 1980s. During past waste handling practices uranium, copper, and other heavy metals were routed to liquid waste streams and ponds near the Columbia River shoreline. The Washington State Department of Health and the Pacific Northwest National Laboratory’s Surface Environmental Surveillance Project sampled various environmental components including river water, riverbank spring water, sediment, fishes, crustaceans, bivalve mollusks, aquatic insects, riparian vegetation, small mammals, and terrestrial invertebrates for analyses of radiological and chemical constituents. The radiological analysis results for water and sediment were used as initial input into the RAD-BCG Calculator. The RAD-BCG Calculator, a computer program that uses an Excel® spreadsheet and Visual Basic® software, showed that maximum radionuclide concentrations measured in water and sediment were lower than the initial screening criteria for concentrations to produce dose rates at existing or proposed limits. Radionuclide concentrations measured in biota samples were used to calculate site-specific bioaccumulation coefficients (Biv) to test the utility of the RAD-BCG-Calculator’s site-specific screening phase. To further evaluate site-specific effects, the default Relative Biological Effect (RBE) for internal alpha particle emissions was reduced by half and the program’s kinetic/allometric calculation approach was initiated. The subsequent calculations showed the initial RAD-BCG Calculator results to be conservative, which is appropriate for screening purposes.

Effect of Lake Trophic Status and Rooted Macrophytes on Community Composition and Abundance of Ammonia-oxidizing Prokaryotes in Freshwater Sediments

DEFF Research Database (Denmark)

Herrmann, Martina; Saunders, Aaron Marc; Schramm, Andreas

2009-01-01

) and slightly higher for AOA in unvegetated sediment and AOA in association with M. alterniflorum (0.01 to 2%), while AOA accounted for up to 5% in the rhizospheres of L. uniflora and J. bulbosus. These results indicate that (i) AOA are at least as numerous as AOB in freshwater sediments, (ii) aquatic...

Eutrophication monitoring for Lake Superior's Chequamegon ...

Science.gov (United States)

A priority for the Lake Superior CSMI was to identify susceptible nearshore eutrophication areas. We developed an integrated sampling design to collect baseline data for Lake Superior’s Chequamegon Bay to understand how nearshore physical processes and tributary loading relate to observed chlorophyll concentrations. Sampling included ship-based water samples combined with vertical CTD casts, continuous in situ towing and data collected from an autonomous underwater glider. Sampling was conducted during June, July and September. The glider collected regional data as part of three extended missions in Lake Superior over the same periods. During the study, two significant storm events impacted the western end of Lake Superior; the first occurred during July 11-12, with 8-10 inches of rain in 24hrs, and the second on July 21 with winds in excess of 161 km/h. Using GIS software, we organized these diverse temporal data sets along a continuous time line with temporally coincident Modis Satellite data to visualize surface sediment plumes in relation to water quality measurements. Preliminary results suggest that both events impacted regional water quality, and that nearshore physical forces (upwelling and currents) influenced the spatial variability. Results comparing in situ measures with remotely sensed images will be discussed. not applicable

Spatial and seasonal patterns of ichthyoplankton assemblages in the Haizhou Bay and its adjacent waters of China

Science.gov (United States)

Li, Zengguang; Ye, Zhenjiang; Wan, Rong

2015-12-01

Surveys were conducted in five voyages in Haizhou Bay and its adjacent coastal area from March to December 2011 during full moon spring tides. The ichthyoplankton assemblages and the environmental factors that affect their spatial and seasonal patterns were determined. Totally 35 and 12 fish egg and larvae taxa were identified, respectively. Over the past several decades, the egg and larval species composition has significantly changed in Haizhou Bay and its adjacent waters, most likely corresponding with the alteration of fishery resources, which are strongly affected by anthropogenic activities and climate change. The Bray-Curtis dissimilarity index identified four assemblages: near-shore bay assemblage, middle bay assemblage and two closely related assemblages (near-shore/middle bay assemblage and middle/edge of bay assemblage). The primary species of each assemblage principally reflected the spawning strategies of adult fish. The near-shore bay assemblage generally occurred in near-shore bay, with depths measuring ichthyoplankton in each assemblage were determined by interactions between biological behavioral traits and oceanographic features, particularly the variation of local conditions within the constraint of a general reproductive strategy. The results of Spearman's rank correlation analysis indicated that both fish egg and larval abundance were positively correlated with depth, which is critical to the oceanographic features in Haizhou Bay.

Extension of 239+240Pu sediment geochronology to coarse-grained marine sediments

Science.gov (United States)

Kuehl, Steven A.; Ketterer, Michael E.; Miselis, Jennifer L.

2012-01-01

Sediment geochronology of coastal sedimentary environments dominated by sand has been extremely limited because concentrations of natural and bomb-fallout radionuclides are often below the limit of measurement using standard techniques. ICP-MS analyses of 239+240Pu from two sites representative of traditionally challenging (i.e., low concentration) environments provide a "proof of concept" and demonstrate a new application for bomb-fallout radiotracers in the study of sandy shelf-seabed dynamics. A kasten core from the New Zealand shelf in the Southern Hemisphere (low fallout), and a vibracore from the sandy nearshore of North Carolina (low particle surface area) both reveal measurable 239+240Pu activities at depth. In the case of the New Zealand site, independently verified steady-state sedimentation results in a 239+240Pu profile that mimics the expected atmospheric fallout. The depth profile of 239+240Pu in the North Carolina core is more uniform, indicating significant sediment resuspension, which would be expected in this energetic nearshore environment. This study, for the first time, demonstrates the utility of 239+240Pu in the study of sandy environments, significantly extending the application of bomb-fallout isotopes to coarse-grained sediments, which compose the majority of nearshore regions.

Diversity, dynamics and biogeography of Chilean benthic nearshore ecosystems: an overview and guidelines for conservation Diversidad, dinámica y biogeografía del ecosistema costero bentónico de Chile: revisión y bases para conservación marina

Directory of Open Access Journals (Sweden)

MIRIAM FERNANDEZ

2000-12-01

Full Text Available Despite Chile has been one of the pioneering countries in studies of human impact on marine communities, and despite the enormous economic and social significance that the marine environment has for the country, the development of marine conservation programs and the scientific basis for sustainability has not kept pace, with the exploitation rate of marine fisheries and the increasing use of the coast for other purposes. Although we think that the establishment of any conservation policies along the vast coastline of Chile must be based on a multitude of approaches and considerations, scientific, biological, and ecological principles should guide much of these efforts. In this paper, we attempt to present a general overview of the current knowledge about the ecology and biogeography of nearshore systems in Chile. Based on the most relevant existing information, our goals are to: 1 Identify major biogeographic and ecological features of nearshore ecosystems, and the obvious gaps in information, 2 identify the most harmful human activities impacting the structure and dynamics of these systems, and 3 suggest the possible use of indicators to assess the conservational status of different environments along the coast. This overview shows, on one side, the geographic areas of deficitary knowledge on nearshore environments that are critical for future marine conservation and management plans, and on the other, the availability of high quality information for other geographic areas along the coast. Regarding the taxonomy and large-scale patterns of species distribution, important gaps in information were detected, however no big changes in the total number of species are expected in the future. There are few large-scale patterns of species distribution are reported in the literature, and in this contribution, but more work needs to be done, particularly for some taxa, to identify areas of high species diversity as well as areas which possess unique

Coastal habitats of the Elwha River, Washington- Biological and physical patterns and processes prior to dam removal

Science.gov (United States)

Duda, Jeffrey J.; Warrick, Jonathan A.; Magirl, Christopher S.

2011-01-01

This report includes chapters that summarize the results of multidisciplinary studies to quantify and characterize the current (2011) status and baseline conditions of the lower Elwha River, its estuary, and the adjacent nearshore ecosystems prior to the historic removal of two long-standing dams that have strongly influenced river, estuary, and nearshore conditions. The studies were conducted as part of the U.S. Geological Survey Multi-disciplinary Coastal Habitats in Puget Sound (MD-CHIPS) project. Chapter 1 is the introductory chapter that provides background and a historical context for the Elwha River dam removal and ecosystem restoration project. In chapter 2, the volume and timing of sediment delivery to the estuary and nearshore are discussed, providing an overview of the sediment stored in the two reservoirs and the expected erosion mechanics of the reservoir sediment deposits after removal of the dams. Chapter 3 describes the geological background of the Olympic Peninsula and the geomorphology of the Elwha River and nearshore. Chapter 4 details a series of hydrological data collected by the MD-CHIPS Elwha project. These include groundwater monitoring, surface water-groundwater interactions in the estuary, an estimated surface-water budget to the estuary, and a series of temperature and salinity measurements. Chapter 5 details the work that has been completed in the nearshore, including the measurement of waves, tides, and currents; the development of a numerical hydrodynamic model; and a description of the freshwater plume entering the Strait of Juan de Fuca. Chapter 6 includes a characterization of the nearshore benthic substrate developed using sonar, which formed a habitat template used to design scuba surveys of the benthic biological communities. Chapter 7 describes the ecological studies conducted in the lower river and estuary and includes characterization of juvenile salmon diets and seasonal estuary utilization patterns using otolith analysis to

Mapping to assess feasibility of using subsurface intakes for SWRO, Red Sea coast of Saudi Arabia

KAUST Repository

Dehwah, Abdullah

2013-11-19

Use of subsurface intakes for seawater reverse osmosis desalination (SWRO) systems is known to improve raw water quality, reduce use of chemicals, improve operational reliability, and reduce the life cycle cost of desalination. A key issue in planning for the development of a SWRO facility that would potentially use a subsurface intake is the characterization of the coastal and nearshore geology of a region to ascertain the types of subsurface intakes that could be used and their respective costs. It is the purpose of this research to document a new methodology that can be used for planning and assessment of the feasibility of using subsurface intake systems for SWRO facilities at any location in the world. The Red Sea shoreline and nearshore area of Saudi Arabia were mapped and sediments were sampled from the Yemen border north of the Jordan border, a distance of about 1,950 km. Seventeen different coastal environments were defined, mapped, and correlated to the feasibility of using various types of subsurface intake systems. Six environments were found to have favorable characteristics for development of large-scale subsurface intakes. The most favorable of these coastal environments includes: (1) beaches and nearshore areas containing carbonate or siliciclastic sands with minimum mud concentrations and environmentally sensitive bottom community biota or fauna (A1, A2, and A3), limestone rocky shorelines with an offshore carbonate or siliciclastic sand bottom underlain by soft limestone and a barren area lying between the shoreline and the offshore reef (B1, B5), and wadi sediments on the beach (mixture of pebbles, gravel, and sand) with a corresponding nearshore area containing either siliciclastic sand and/or a marine hard ground (soft limestone or sandstone) (C2). It was found that seabed galleries were the subsurface intake type with the highest feasibility for development of large-capacity intakes. The geological characteristics of the offshore sea bottom

Short Term CO2 Enrichment Increases Carbon Sequestration of Air-Exposed Intertidal Communities of a Coastal Lagoon

Directory of Open Access Journals (Sweden)

Amrit K. Mishra

2018-01-01

Full Text Available In situ production responses of air-exposed intertidal communities under CO2 enrichment are reported here for the first time. We assessed the short-term effects of CO2 on the light responses of the net community production (NCP and community respiration (CR of intertidal Z. noltei and unvegetated sediment communities of Ria Formosa lagoon, when exposed to air. NCP and CR were measured in situ in summer and winter, under present and CO2 enriched conditions using benthic chambers. Within chamber CO2 evolution measurements were carried out by a series of short-term incubations (30 min using an infra-red gas analyser. Liner regression models fitted to the NCP-irradiance responses were used to estimate the seasonal budgets of air-exposed, intertidal production as determined by the daily and seasonal variation of incident photosynthetic active radiation. High CO2 resulted in higher CO2 sequestration by both communities in both summer and winter seasons. Lower respiration rates of both communities under high CO2 further contributed to a potential negative climate feedback, except in winter when the CR of sediment community was higher. The light compensation points (LCP (light intensity where production equals respiration of Z. noltei and sediment communities also decreased under CO2 enriched conditions in both seasons. The seasonal community production of Z. noltei was 115.54 ± 7.58 g C m−2 season−1 in summer and 29.45 ± 4.04 g C m−2 season−1 in winter and of unvegetated sediment was 91.28 ± 6.32 g C m−2 season−1 in summer and 25.83 ± 4.01 g C m−2 season−1 in winter under CO2 enriched conditions. Future CO2 conditions may increase air-exposed seagrass production by about 1.5-fold and unvegetated sediments by about 1.2-fold.

Yearly to decennial beach morphodynamics south the Arcachon inlet, France from satellite observations

Science.gov (United States)

Dehouck, Aurelie; Sénéchal, Nadia; Lafon, Virginie; Almar, Rafael; Castelle, Bruno; Froidefond, Jean-Marie

2010-05-01

Historical shoreline oscillations along adjacent beaches south the Arcachon tidal inlet (south-west France) have been directly controled by sediment inputs carried through the inlet by the littoral drift. In parallell, field observations aiming at understanding high frequency processes governing short-term beach morphodynamics are conducted on a very few local beach sites, among them the beach of Biscarrosse located 12 km south the inlet where video cameras are implemented. It have been suggested that Biscarrosse Beach was recently affected by nearshore large-scale sandy structures propagating southward and originating from the inlet. But, basic information about the space and time dynamics of these bodies is actually missing. In addition, there is a spatial gap in knowledge concerning the hydro and morphodynamics particularities along the south-Gironde coast, i.e. between the ebb-delta and adjacent beaches which have been subject to intense monitoring and the beach of Biscarrosse. In fact, this is a complex area where beaches are dominated by channeled tidal flows on one hand, while typical swell-dominated beaches extend for several tens of kilometers on the other hand, characterized by rhythmic crescentic outer bar patterns and oblique bar-and-rip inner bar. So, large-scale observations are needed to fill the spatial gap in order to provide a comprehensive understanding of nearshore sandbar morphodynamics. To achieve this objective, we benefited from satellite remote sensing timeseries that were recently made available by the CNES, the French Space Agency, through the Kalideos database. It encompasses SPOT high resolution (10-m and 20-m pixels) multispectral imagery from 1986 to 2009. The method is based on a semi-empirical algorithm using seawater optical properties to invert satellite reflectance at the sea level into water depth (Lee et al., 1998; Lafon et al., 2002). The algorithm was calibrated with in situ reflectance measurements collected in the nearshore

Real-time distribution of pelagic fish: combining hydroacoustics, GIS and spatial modelling at a fine spatial scale.

Science.gov (United States)

Muška, Milan; Tušer, Michal; Frouzová, Jaroslava; Mrkvička, Tomáš; Ricard, Daniel; Seďa, Jaromír; Morelli, Federico; Kubečka, Jan

2018-03-29

Understanding spatial distribution of organisms in heterogeneous environment remains one of the chief issues in ecology. Spatial organization of freshwater fish was investigated predominantly on large-scale, neglecting important local conditions and ecological processes. However, small-scale processes are of an essential importance for individual habitat preferences and hence structuring trophic cascades and species coexistence. In this work, we analysed the real-time spatial distribution of pelagic freshwater fish in the Římov Reservoir (Czechia) observed by hydroacoustics in relation to important environmental predictors during 48 hours at 3-h interval. Effect of diurnal cycle was revealed of highest significance in all spatial models with inverse trends between fish distribution and predictors in day and night in general. Our findings highlighted daytime pelagic fish distribution as highly aggregated, with general fish preferences for central, deep and highly illuminated areas, whereas nighttime distribution was more disperse and fish preferred nearshore steep sloped areas with higher depth. This turnover suggests prominent movements of significant part of fish assemblage between pelagic and nearshore areas on a diel basis. In conclusion, hydroacoustics, GIS and spatial modelling proved as valuable tool for predicting local fish distribution and elucidate its drivers, which has far reaching implications for understanding freshwater ecosystem functioning.

Reverse trends of TEX86 temperature in coastal areas of the East China Sea over the last 100 years: implication for global warming and regional circulation

Science.gov (United States)

Cao, Y.; Xing, L.; Zhang, T.

2017-12-01

To reconstruct and compare the SST changes in different regions of the ECS over the last 100 years, in this study, we analyzed iGDGTs compounds and TEX86 index in two sediment cores (DH5-1 and DH6-2) from the inner shelf of the East China Sea (ECS). GDGT-0 and GDGT-5 in the two cores account for 80% of iGDGTs, significantly more abundant than the other iGDGTs compounds. It is also found that iGDGTs are mainly derived from marine Thaumarchaeota. TEXH86 temperatures varied from 17 °C to 22 °C (average 19.4 °C), showing a gradual increase in Core DH5-1 near the Changjiang River Estuary, corresponding to global warming and temperature rise in the ECS over the last 100 years. However, in Core DH6-2 further away from the Changjiang River Estuary, TEXH86 temperatures gradually decreased over the last 80 years with a range of 15.3 °C-18.3 °C, which is attributed to the strengthened near-shore Kuroshio Branch Current transporting more subsurface cold water to the ECS coastal area. In future, more sites should be investigated to confirm the range of the coastal area where the decrease in SST is caused by upwelling subsurface water.

Emerging marine protected area networks in the coral triangle: Lessons and way forward

Directory of Open Access Journals (Sweden)

Stuart J Green

2011-01-01

Full Text Available Marine protected areas (MPAs and MPA networks are valuable tools for protecting coral reef habitats and managing near-shore fisheries, while playing an essential role in the overall conservation of marine biodiversity. In addition, MPAs and their networks are often the core strategy for larger scale and more integrated forms of marine resource management that can lead to ecosystem-based management regimes for seascapes and eco-regions. This study conducted in 2008 documents the status of selected MPAs and MPA networks in Indonesia, Philippines and Papua New Guinea, to better understand development and their level of success in the Coral Triangle. Findings reveal that substantial gaps exist between the theory and practice of creating functional MPA networks. Across these sites, biophysical and social science knowledge, required to build functional and effective MPAs or MPA networks, lagged behind substantially. Aspects that appeared to require the most attention to improve MPA network effectiveness included essential management systems, institutional arrangements, governance and sustainable financing. Common indicators of success such as increased fish catch and habitat quality parameters were consistently associated with several independent variables: sustainable financing for management, clarity of MPA network rules, enforcement by community level enforcers, local skills development, and involvement in management by local elected politicians, a functional management board, multi-stakeholder planning mechanisms and participatory biophysical assessments. Conclusions are that although considerable investments have been made in MPAs and potential MPA networks in the Coral Triangle, management effectiveness is generally poor throughout the region and that not many large, formally declared MPAs are well managed.

South Baltic representative coastal field surveys, including monitoring at the Coastal Research Station in Lubiatowo, Poland

Science.gov (United States)

Ostrowski, Rafał; Schönhofer, Jan; Szmytkiewicz, Piotr

2016-10-01

The paper contains a brief description of selected investigations carried out in the south Baltic coastal zone, with the particular focus on the history and recent activities conducted at the Coastal Research Station in Lubiatowo (CRS Lubiatowo), Poland. These activities comprise field investigations of nearshore hydrodynamic, lithodynamic, and morphodynamic processes. The study area is a sandy multi-bar shore with a mild slope, much exposed to the impact of waves approaching from NW-NE sector. The shore has a dissipative character which means that the wave energy is subject to gradual dissipation in the nearshore zone and only a small part of this energy is reflected by the shore. Due to the big wind fetch in N-NNE direction, the location of CRS Lubiatowo is favourable to registration of the maximum values of parameters of hydrodynamic and morphodynamic processes which occur in the Baltic during extreme storms.

Understanding Coral's Short-term Adaptive Ability to Changing Environment

Science.gov (United States)

Tisthammer, K.; Richmond, R. H.

2016-02-01

Corals in Maunalua Bay, Hawaii are under chronic pressures from sedimentation and terrestrial runoffs containing multiple pollutants as a result of large scale urbanization that has taken place in the last 100 years. However, some individual corals thrive despite the prolonged exposure to these environmental stressors, which suggests that these individuals may have adapted to withstand such stressors. A recent survey showed that the lobe coral Porites lobata from the `high-stress' nearshore site had an elevated level of stress ixnduced proteins, compared to those from the `low-stress,' less polluted offshore site. To understand the genetic basis for the observed differential stress responses between the nearshore and offshore P. lobata populations, an analysis of the lineage-scale population genetic structure, as well as a reciprocal transplant experiment were conducted. The result of the genetic analysis revealed a clear genetic differentiation between P. lobata from the nearshore site and the offshore site. Following the 30- day reciprocal transplant experiment, protein expression profiles and other stress-related physiological characteristics were compared between the two populations. The experimental results suggest that the nearshore genotype can cope better with sedimentation/pollutants than the offshore genotype. This indicates that the observed genetic differentiation is due to selection for tolerance to these environmental stressors. Understanding the little-known, linage-scale genetic variation in corals offers a critical insight into their short-term adaptive ability, which is indispensable for protecting corals from impending environmental and climate change. The results of this study also offer a valuable tool for resource managers to make effective decisions on coral reef conservation, such as designing marine protected areas that incorporate and maintain such genetic diversity, and establishing acceptable pollution run-off levels.

Empirical quantification of lacustrine groundwater discharge - different methods and their limitations

Science.gov (United States)

Meinikmann, K.; Nützmann, G.; Lewandowski, J.

2015-03-01

Groundwater discharge into lakes (lacustrine groundwater discharge, LGD) can be an important driver of lake eutrophication. Its quantification is difficult for several reasons, and thus often neglected in water and nutrient budgets of lakes. In the present case several methods were applied to determine the expansion of the subsurface catchment, to reveal areas of main LGD and to identify the variability of LGD intensity. Size and shape of the subsurface catchment served as a prerequisite in order to calculate long-term groundwater recharge and thus the overall amount of LGD. Isotopic composition of near-shore groundwater was investigated to validate the quality of catchment delineation in near-shore areas. Heat as a natural tracer for groundwater-surface water interactions was used to find spatial variations of LGD intensity. Via an analytical solution of the heat transport equation, LGD rates were calculated from temperature profiles of the lake bed. The method has some uncertainties, as can be found from the results of two measurement campaigns in different years. The present study reveals that a combination of several different methods is required for a reliable identification and quantification of LGD and groundwater-borne nutrient loads.

Nearshore versus Offshore

DEFF Research Database (Denmark)

Klinge Jacobsen, Henrik; Hevia Koch, Pablo Alejandro; Wolter, Christoph

Currently there exist high expectations for the development of wind energy, particularly in Europe, out of whichoffshore wind turbine developments will be central as tools to achieve current energy targets. The question betweennearshore and (far)-offshore is particularly relevant, both because of...

The durban beach monitoring program: simple surveys speak volumes

CSIR Research Space (South Africa)

de Wet, p

2010-10-01

Full Text Available program: simple surveys speak volumes Pierre de Wet, Andrew Mather, Andr? Theron SAEON summit, 6 October 2010 ? CSIR 2010 Slide 1www.csir.co.za Outline ? Background / History ? Monitoring area circle6 Examples of survey data & trends circle6...) and near-shore deposition cf. classical understanding / scheme ? CSIR 2010 Slide 6 ? id. areas vulnerable to erosion ? effect of replenishment rates / locations visible Beach survey data s h o r e l i n e p o s i t i o n [ m...

Soil erosion and causative factors at Vandenberg Air Force Base, California

Science.gov (United States)

Butterworth, Joel B.

1988-01-01

Areas of significant soil erosion and unvegetated road cuts were identified and mapped for Vandenberg Air Force Base. One hundred forty-two eroded areas (most greater than 1.2 ha) and 51 road cuts were identified from recent color infrared aerial photography and ground truthed to determine the severity and causes of erosion. Comparison of the present eroded condition of soils (as shown in the 1986 photography) with that in historical aerial photography indicates that most erosion on the base took place prior to 1928. However, at several sites accelerated rates of erosion and sedimentation may be occurring as soils and parent materials are eroded vertically. The most conspicuous erosion is in the northern part of the base, where severe gully, sheet, and mass movement erosion have occurred in soils and in various sedimentary rocks. Past cultivation practices, compounded by highly erodible soils prone to subsurface piping, are probably the main causes. Improper range management practices following cultivation may have also increased runoff and erosion. Aerial photography from 1986 shows that no appreciable headward erosion or gully sidewall collapse have occurred in this area since 1928.

Storm impacts on a high energy sandy beach system, northwest Ireland: short (event) to long term (decadal) behaviour

Science.gov (United States)

Guisado-Pintado, Emilia; Jackson, Derek; Cooper, Andrew; O'Connor, Marianne

2017-04-01

Long-term monitoring of beach dynamics is an important element in risk prevention and management of both natural and human resources at the coast. The predicted intensification in storminess (frequency, duration and magnitude), partly associated with climate change, represents a pressing concern for coastal communities globally and has undoubtedly led to an improvement in available techniques and technologies for observation and analysis. Here we examine a high energy Atlantic beach system at Five Fingers strand (NW Ireland) to help understand hydrodynamic forcing on beach response under various wave energy scenarios. The system, which has been modally attuned to a large swell wave environment, periodically undergoes significant morphological changes over various spatial and temporal scales manifest in the development and movements of dynamic nearshore bars and a nearshore ebb-tide delta. A combination of field and laboratory techniques (GPS, Terrestrial Laser Scanning (TLS) Instrumentation, Drone surveys) implemented from the shoreface to the beach, captures the response and evolution of the system over the short (event), medium (weeks to months) and long-term (multiyear) timescale. Numerical modelling of nearshore wave hydrodynamics (using SWAN wave simulation model) helps understanding wave forcing across shoreface area and is ran under a number of iterative time intervals. Here, we investigate the role of infrequent and sometimes extreme events in the system to understand the importance of clustering of storminess and the occurrence of single high-magnitude storm events that perturb the inlet-beach system and thus induce key morphodynamic changes. Preliminary results show that ultimately the configuration of the ebb-tide channel influences the geomorphic response of the system. In the short term, a storm induced erosion of the shoreface is observed, which also appears to lead to changes in the ebb-tide channel, and ultimately the welding of a nearshore bar

Effect of pollution on the distribution of chaetognaths in the nearshore waters of Bombay

Digital Repository Service at National Institute of Oceanography (India)

Nair; Gajbhiye, S.N.; Desai, B.N.

polluted with sewage. Incidence of chaetognaths at sewage polluted areas was limited mostly to periods of high tide; with population density much less (max 10.m super(-3)) than that of areas free of pollution (max 40.m super(-3)). Sagitta bedoti...

Benthic fauna of Kakinada bay and backwaters, east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Rathod, V.; Ansari, Z.A.; Parulekar, A.H.

. Nematodes, polychaetes, foraminifera and turbellarians were the major groups constituting the bulk of meiofauna, both in the backwaters and near-shore region. Macrofaunal diversity was higher in the near-shore region. Impoverishment of fauna...

Development of a numerical 2-dimensional beach evolution model

DEFF Research Database (Denmark)

Baykal, Cüneyt

2014-01-01

This paper presents the description of a 2-dimensional numerical model constructed for the simulation of beach evolution under the action of wind waves only over the arbitrary land and sea topographies around existing coastal structures and formations. The developed beach evolution numerical model...... is composed of 4 submodels: a nearshore spectral wave transformation model based on an energy balance equation including random wave breaking and diffraction terms to compute the nearshore wave characteristics, a nearshore wave-induced circulation model based on the nonlinear shallow water equations...... to compute the nearshore depth-averaged wave-induced current velocities and mean water level changes, a sediment transport model to compute the local total sediment transport rates occurring under the action of wind waves, and a bottom evolution model to compute the bed level changes in time based...

Plankton studies in the estuarine and nearshore regions of Mandovi and Zuari

Digital Repository Service at National Institute of Oceanography (India)

Rajagopal, M.D.

Biological and chemical data collected for the preparation of a masterplan for pollution control in the rivers Mandovi and Zauri and the adjacent coastal area were processed to study the ecological conditions. Both phytoplankton and zooplankton...

Biological and geophysical aspects of coastal structures

Digital Repository Service at National Institute of Oceanography (India)

Ramana, M.V.

Geological processes, that occur in the nearshore environment : The nearshore, environments have been strongly influencEd. by sealevel changes throughout the geological history. Much of the shallow-water region is also strongly affectEd. by waves...

Large river bed sediment characterization with low-cost sidecan sonar: Case studies from two setting in the Colorado (Arizona) and Penobscot (Maine) Rivers

Science.gov (United States)

Buscombe, Daniel D.; Grams, Paul E.; Melis, Theodore S.; Smith, Sean

2015-01-01

Mapping subaqueous riverbed sediment grain size across channels and in nearshore areas typically used by fish and benthic invertebrates is difficult where and when the water flow is too swift or deep to wade yet impractical to access with large boats and instruments. Fluvial characteristics can further constrain sampling options, particularly where flow depth, water column turbidity or channel bottom structure prohibit use of aerial or bottom deployed imaging platforms.

Tools and methods for evaluating and refining alternative futures for coastal ecosystem management—the Puget Sound Ecosystem Portfolio Model

Science.gov (United States)

Byrd, Kristin B.; Kreitler, Jason R.; Labiosa, William B.

2011-01-01

The U.S. Geological Survey Puget Sound Ecosystem Portfolio Model (PSEPM) is a decision-support tool that uses scenarios to evaluate where, when, and to what extent future population growth, urban growth, and shoreline development may threaten the Puget Sound nearshore environment. This tool was designed to be used iteratively in a workshop setting in which experts, stakeholders, and decisionmakers discuss consequences to the Puget Sound nearshore within an alternative-futures framework. The PSEPM presents three possible futures of the nearshore by analyzing three growth scenarios developed out to 2060: Status Quo—continuation of current trends; Managed Growth—adoption of an aggressive set of land-use management policies; and Unconstrained Growth—relaxation of land-use restrictions. The PSEPM focuses on nearshore environments associated with barrier and bluff-backed beaches—the most dominant shoreforms in Puget Sound—which represent 50 percent of Puget Sound shorelines by length. This report provides detailed methodologies for development of three submodels within the PSEPM—the Shellfish Pollution Model, the Beach Armoring Index, and the Recreation Visits Model. Results from the PSEPM identify where and when future changes to nearshore ecosystems and ecosystem services will likely occur within the three growth scenarios. Model outputs include maps that highlight shoreline sections where nearshore resources may be at greater risk from upland land-use changes. The background discussed in this report serves to document and supplement model results displayed on the PSEPM Web site located at http://geography.wr.usgs.gov/pugetSound/.

Changes in distributional patterns of plaice Pleuronectes platessa in the central and eastern North Sea; do declining nutrient loadings play a role?

Science.gov (United States)

Støttrup, Josianne G.; Munk, Peter; Kodama, Masashi; Stedmon, Colin

2017-09-01

Since the beginning of the 1990s, there has been a change in the relative distribution of smaller age-classes of plaice Pleuronectes platessa (age 1-3) in the North Sea. The abundances have increased in deeper, more offshore areas, while coastal abundances have been stagnant or declining. For the same time period available time series data on nutrient conditions in the coastal North Sea area show that the freshwater nitrogen loading has decreased by about 50%. While nutrient concentrations in the ambient environment have been shown to influence growth in juvenile plaice through influence on their prey, we here inspect the potential linkage between distributional changes in plaice and the decline in nutrient loading. We compare plaice observations in coastal areas in the eastern North Sea, which have experienced large changes in eutrophication, with observations for the Dogger Bank, a large sandbank in a shallow offshore area of the North Sea. The Dogger Bank, was used as a reference location assuming this area has been less influenced from coastal eutrophication but similar regional climate conditions, and here we found no changes in the abundances of juvenile plaice. The increase in the use of offshore habitats as nursery areas by juvenile plaice in the North Sea appears not related to water depth per se but driven by specific processes dominating in near-shore areas and may be related to changes in nutrient loadings. This point to the importance of separating more general depth-related factors from conditions specific for near-shore areas, such as nutrient loadings in coastal waters and export offshore. The concurrent changes in environment and in distribution of juvenile plaice may have implications for environmental and fisheries management.

Performance Monitoring of a Nearshore Berm at Ft. Myers Beach, Florida

Science.gov (United States)

2013-08-01

Figure 14. Establishing a temporary benchmark. ERDC/CHL TR-13-11 28 Visually estimated vegetation/ toe -of- dune line, MHHW line (identified...sediment samples were taken at the toe of the dune (where present), backbeach, high tide line, mean sea level, low tide line, and then at approximately...2-ft, 4-ft, 6-ft, and 8-ft water depths. In the berm area, surface sediment samples were taken at the toe of the dune (where present), backbeach

Onshore and offshore geologic map of the Coal Oil Point area, southern California

Science.gov (United States)

Dartnell, Pete; Conrad, James E.; Stanley, Richard G.; Guy R. Cochrane, Guy R.

2011-01-01

Point area. Results from this report directly address issues raised in the California Ocean Protection Act (COPA) Five Year Strategic Plan. For example, one of the guiding principles of the COPA five-year strategic plan is to 'Recognize the interconnectedness of the land and the sea, supporting sustainable uses of the coast and ensuring the health of ecosystems.' Results from this USGS report directly connect the land and sea with the creation of both a seamless onshore and offshore digital terrain model (DTM) and geologic map. One of the priority goals (and objectives) of the COPA plan is to 'monitor and map the ocean environment to provide data about conditions and trends.' Maps within this report provide land and sea geologic information for mapping and monitoring nearshore sediment processes, pollution transport, and sea-level rise and fall.

Development of a Hydrodynamic and Transport model of Bellingham Bay in Support of Nearshore Habitat Restoration

Energy Technology Data Exchange (ETDEWEB)

Wang, Taiping; Yang, Zhaoqing; Khangaonkar, Tarang

2010-04-22

root mean square error values for surface elevation, velocity, temperature, and salinity time series are 0.11 m, 0.10 m/s, 1.28oC, and 1.91 ppt, respectively. The model was able to reproduce the salinity and temperature stratifications inside Bellingham Bay. Wetting and drying processes in tidal flats in Bellingham Bay, Samish Bay, and Padilla Bay were also successfully simulated. Both model results and observed data indicated that water surface elevations inside Bellingham Bay are highly correlated to tides. Circulation inside the bay is weak and complex and is affected by various forcing mechanisms, including tides, winds, freshwater inflows, and other local forcing factors. The Bellingham Bay model solution was successfully linked to the NOAA oil spill trajectory simulation model “General NOAA Operational Modeling Environment (GNOME).” Overall, the Bellingham Bay model has been calibrated reasonably well and can be used to provide detailed hydrodynamic information in the bay and adjacent water bodies. While there is room for further improvement with more available data, the calibrated hydrodynamic model provides useful hydrodynamic information in Bellingham Bay and can be used to support sediment transport and water quality modeling as well as assist in the design of nearshore restoration scenarios.

Nursery use of shallow habitats by epibenthic fishes in Maine nearshore waters

Science.gov (United States)

Lazzari, M. A.; Sherman, S.; Kanwit, J. K.

2003-01-01

Species richness and abundance of epibenthic fishes were quantified with daytime beam trawl tows in shallow water habitats during April-November 2000 of three mid-coast Maine estuaries: Casco Bay, Muscongus Bay and the Weskeag River. Five shallow (Gasterosteus aculeatus, Apeltes quadracus, Pungitius pungitius, Myoxocephalus aenaeus, and Cylcopterus lumpus. The fish community of mid-coast estuaries was dominated by young-of-the-year (YOY) and juvenile fishes and all of the habitat types function as nursery areas. Twelve species (38%) of commercial and recreational importance were collected in the three estuaries, but the percentage was higher in Casco Bay (44%) and the Weskeag River (46%). These species included Anguilla rostrata, Clupea harengus, Gadus morhua, Microgadus tomcod, Pollachius virens, Urophycis chuss, Urophycis regia, Urophycis tenuis, Osmerus mordax, Macrozoarces americanus, Tautogolabrus adspersus, and Pleuronectes americanus. Four species, G. morhua, M. tomcod, P. virens, and U. tenuis were more common in spring than summer or autumn. P. americanus was most abundant in summer followed by spring and autumn. This study documents the importance of shallow estuarine areas in Maine as nurseries for these species.

Franz Josef Land: extreme northern outpost for Arctic fishes

Directory of Open Access Journals (Sweden)

Natalia V. Chernova

2014-12-01

Full Text Available The remote Franz Josef Land (FJL Archipelago is the most northerly land in Eurasia and its fish fauna, particularly in nearshore habitats, has been poorly studied. An interdisciplinary expedition to FJL in summer 2013 used scuba, seines, and plankton nets to comprehensively study the nearshore fish fauna of the archipelago. We present some of the first underwater images for many of these species in their natural habitats. In addition, deep water drop cameras were deployed between 32 and 392 m to document the fish fauna and their associated habitats at deeper depths. Due to its high latitude (79°–82°N, extensive ice cover, and low water temperatures (<0 °C much of the year, the fish diversity at FJL is low compared to other areas of the Barents Sea. Sixteen species of fishes from seven families were documented on the expedition, including two species previously unknown to the region. One Greenland shark, Somniosus microcephalus (Somniosidae, ca. 2 m in length, was recorded by drop camera near Hayes Island at 211 m, and Esipov’s pout, Gymnelus esipovi (Zoarcidae, was collected at Wilton Island at 15 m in a kelp forest. Including the tape-body pout, Gymnelus taeniatus, described earlier from the sub-littoral zone of Kuhn Island, 17 fish species are now known from FJL’s nearshore waters. Species endemic to the Arctic accounted for 75% of the nearshore species observed, followed by species with wider ranges. A total of 43 species from 15 families are known from FJL with the majority of the records from offshore trawl surveys between 110 and 620 m. Resident species have mainly high Arctic distributions, while transient species visit the archipelago to feed (e.g., Greenland shark, and others are brought by currents as larvae and later migrate to spawn grounds in the south (e.g., Atlantic cod Gadus morhua, Capelin Mallotus villosus, Beaked redfish Sebastes mentella. Another species group includes warmer-water fishes that are rare waifs (e

Coastal nutrification and coral health at Porto Seguro reefs, Brazil

Science.gov (United States)

Costa, O.; Attrill, M.; Nimmo, M.

2003-04-01

Human activities have substantially increased the natural flux of nutrients to coastal systems worldwide. In Brazilian reefs, all major stresses (sedimentation, overfishing, tourism-related activities and nutrification) are human induced. To assess nutrification levels in Brazilian coastal reefs, measurements of the distribution patterns of nutrients and chlorophyll concentrations were conducted in three nearshore and offshore reefs with distinct nutrient inputs along the south coast of Bahia State. Seawater and porewater samples were analysed for soluble reactive phosphorus, total oxidised nitrogen and reactive silica. Benthic surveys were performed at all sites to investigate the relationships between benthic community composition and nutrient and chlorophyll concentrations. Sampling was undertaken in dry and rainy seasons. Results of both seawater and porewater nutrient measurements revealed the occurrence of consistent spatial and temporal patterns. An inshore-offshore gradient reflects the occurrence of land-based point sources, with significant amount of nutrients being delivered by human activities on the coast (untreated sewage and groundwater seepage). Another spatial gradient is related to distance from a localized source of pollution (an urban settlement without sewerage treatment) with two nearshore reefs presenting distinct nutrient and chlorophyll concentrations. Seasonal variations suggest that submarine groundwater discharge (SGD) is the primary source of nutrients for the coastal reefs during rainy season. The data also suggests that the SGD effect is not restricted to nearshore reefs, and may be an important factor controlling the differences between landward and seaward sides on the offshore reef. Benthic community assessment revealed that turf alga is the dominant group in all studied reefs and that zoanthids are the organisms most adapted to take advantage of nutrient increase in coastal areas. At nearshore reefs, there was a negative

The combined risk of extreme tropical cyclone winds and storm surges along the U.S. Gulf of Mexico Coast

Science.gov (United States)

Trepanier, J. C.; Yuan, J.; Jagger, T. H.

2017-03-01

Tropical cyclones, with their nearshore high wind speeds and deep storm surges, frequently strike the United States Gulf of Mexico coastline influencing millions of people and disrupting offshore economic activities. The combined risk of occurrence of tropical cyclone nearshore wind speeds and storm surges is assessed at 22 coastal cities throughout the United States Gulf of Mexico. The models used are extreme value copulas fitted with margins defined by the generalized Pareto distribution or combinations of Weibull, gamma, lognormal, or normal distributions. The statistical relationships between the nearshore wind speed and storm surge are provided for each coastal city prior to the copula model runs using Spearman's rank correlations. The strongest significant relationship between the nearshore wind speed and storm surge exists at Shell Beach, LA (ρ = 0.67), followed by South Padre Island, TX (ρ = 0.64). The extreme value Archimedean copula models for each city then provide return periods for specific nearshore wind speed and storm surge pairs. Of the 22 cities considered, Bay St. Louis, MS, has the shortest return period for a tropical cyclone with at least a 50 ms-1 nearshore wind speed and a 3 m surge (19.5 years, 17.1-23.5). The 90% confidence intervals are created by recalculating the return periods for a fixed set of wind speeds and surge levels using 100 samples of the model parameters. The results of this study can be utilized by policy managers and government officials concerned with coastal populations and economic activity in the Gulf of Mexico.

Benthic fluxes in a tropical estuary and their role in the ecosystem

Digital Repository Service at National Institute of Oceanography (India)

Pratihary, A.K.; Naqvi, S.W.A.; Naik, H.; Thorat, B.R.; Narvenkar, G.; Manjunatha, B.R.; Rao, V.P.

in the Estuary. Based on these observations we hypothesize that it is mainly benthic NH 4 + efflux that sustains high estuarine productivity in the NO 3 - depleted dry season. Keywords: Nutrients; Primary production; Denitrification; Bioturbation; Benthic..., nearshore and continental shelves occupy just about 10 % of the global oceanic area, between 30-50 % of the marine primary production occurs in these regions (Romankevich, 1984; Walsh, 1991) which also sustains about 90 % of the fisheries resource. Coastal...

Detection of Oil near Shorelines during the Deepwater Horizon Oil Spill Using Synthetic Aperture Radar (SAR

Directory of Open Access Journals (Sweden)

Oscar Garcia-Pineda

2017-06-01

Full Text Available During any marine oil spill, floating oil slicks that reach shorelines threaten a wide array of coastal habitats. To assess the presence of oil near shorelines during the Deepwater Horizon (DWH oil spill, we scanned the library of Synthetic Aperture Radar (SAR imagery collected during the event to determine which images intersected shorelines and appeared to contain oil. In total, 715 SAR images taken during the DWH spill were analyzed and processed, with 188 of the images clearly showing oil. Of these, 156 SAR images showed oil within 10 km of the shoreline with appropriate weather conditions for the detection of oil on SAR data. We found detectable oil in SAR images within 10 km of the shoreline from west Louisiana to west Florida, including near beaches, marshes, and islands. The high number of SAR images collected in Barataria Bay, Louisiana in 2010 allowed for the creation of a nearshore oiling persistence map. This analysis shows that, in some areas inside Barataria Bay, floating oil was detected on as many as 29 different days in 2010. The nearshore areas with persistent floating oil corresponded well with areas where ground survey crews discovered heavy shoreline oiling. We conclude that satellite-based SAR imagery can detect oil slicks near shorelines, even in sheltered areas. These data can help assess potential shoreline oil exposure without requiring boats or aircraft. This method can be particularly helpful when shoreline assessment crews are hampered by difficult access or, in the case of DWH, a particularly large spatial and temporal spill extent.

Changes in zinc speciation with mine tailings acidification in a semi-arid weathering environment

OpenAIRE

Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon

2011-01-01

High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semi-arid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the...

Assessment of nutrient removal in vegetated and unvegetated gravel bed mesocosm treatment wetlands

International Nuclear Information System (INIS)

Dougherty, J.M.; Werker, A.G.

2002-01-01

Constructed wetlands are being considered more frequently as an option for wastewater treatment around the world. However, widespread application of this technology requires further understanding of the system performance. Such knowledge is necessary to develop improved models, better characterize the essential treatment processes and improve the reliability in performance. The goal of achieving predictable levels of wastewater amelioration with minimal performance variability is an essential part of securing regulatory approval for treatment wetland systems. Laboratory mesocosms or unit-wetlands are being utilized and novel in-situ calibration methods are being applied to reference and compare kinetics of wastewater contaminant transformations. Tracer studies are being applied to reference plant and biofilm development within and between mesocosms with respect to carbon and nitrogen. Through detailed characterization of these unit wetlands, aspects of nutrient removal are being systematically examined. This paper will highlight the unit-wetland approach and experimental results juxtaposed the relevant literature surrounding wetland treatment of wastewater. (author)

The effect of ship scrapping industry and its associated wastes on the biomass production and biodiversity of biota in in situ condition at Alang.

Science.gov (United States)

Tewari, A; Joshi, H V; Trivedi, R H; Sravankumar, V G; Raghunathan, C; Khambhaty, Y; Kotiwar, O S; Mandal, S K

2001-06-01

The main pollutants for the ship scrapping industry and its associated wastes at Alang are heavy metals, petroleum hydrocarbon and bacterial contaminations. The concentration of iron, manganese, cobalt, copper, zinc, lead, cadmium, nickel and mercury were 25 to 15,500% more at nearshore station of Alang as compared to control site at Piram. The concentration of heavy metals in the nearshore station of Alang was always higher than its concentration at 10 km away. The concentration of petroleum hydrocarbon was 16,973 and 53,900% more at the nearshore and 10 km away respectively at Alang as compared to controls. The concentration of chlorophyll-a and phaeophytin were in non-detectable range (Alang as compared to controls. The total viable count, total coliform, Escherichia coli, Vibrio cholerae, Vibrio parahaemolyticus and other Vibrio, Streptococcus faecalis, Shigella, Salmonella, Proteus, and Klebsiella were always higher (17%-605%) at the nearshore station of Alang as compared to control. Similar trend was observed at 10 km away from Alang. Bacteria in sediment also showed the same pattern of variation. Phytoplankton counts at the nearshore station and 10 km away from Alang were only slightly raised. In contrast to phytoplankton, the zooplankton showed considerable reduction of growth (-10 to -66%) at Alang.

Effect of Nearshore Islands on Tsunami Inundation in Shadow Zones

Science.gov (United States)

Goertz, J.; Kaihatu, J. M.; Kalligeris, N.; Lynett, P. J.; Synolakis, C.

2017-12-01

Field surveys performed in the wake of the 2010 Mentawai tsunami event have described the belief of local residents that offshore islands serve as possible tsunami sheltering mechanisms, reducing the corresponding inundation on beaches behind the islands, despite the fact that deduced inundation from debris lines show this to be in fact untrue (Hill et al. 2012). Recent numerical model studies (Stefanakis et al. 2014) have shown that inundation levels on beaches behind conical islands are indeed higher than they are on open coastlines. While work has been done on tsunami amplification on the lee side of islands (Briggs et al. 1995), no work has been done concerning tsunami inundation on beach areas behind the islands. A series of experiments to address this were conducted in the Directional Wave Basin (DWB) at the O.H. Hinsdale Wave Research Laboratory at Oregon State University in summer 2016. A series of four sheet metal islands (two with a full conical section, two truncated at the water line) were placed at varying distances from the toe of a 1/10 sloping beach. Incident wave conditions consisting of solitary waves and full-stroke "dam break" waves were run over the islands. Free surface elevations, velocities, and beach runup were measured, with the intent of determining relationships between the wave condition, the island geometry and distance from the beach, and the tsunami characteristics. A series of runup measurements from a particular set of experiments can be seen in Figure 1. Based on these preliminary analyses, it was determined that: A) inundation was always amplified behind the island relative to areas outside this shadow zone; and B) inundation was generally highest with the island closest to the beach, except in the case where the tsunami wave broke prior to reaching the island. In this latter scenario, the inundation behind the island increased with island distance from the beach. The development of relationships between the inundation levels

Life at the hyperarid margin: novel bacterial diversity in arid soils of the Atacama Desert, Chile

Science.gov (United States)

Neilson, Julia W.; Quade, Jay; Ortiz, Marianyoly; Nelson, William M.; Legatzki, Antje; Tian, Fei; LaComb, Michelle; Betancourt, Julio L.; Wing, Rod A.; Soderlund, Carol A.; Maier, Raina M.

2012-01-01

Nearly half the earth's surface is occupied by dryland ecosystems, regions susceptible to reduced states of biological productivity caused by climate fluctuations. Of these regions, arid zones located at the interface between vegetated semiarid regions and biologically unproductive hyperarid zones are considered most vulnerable. The objective of this study was to conduct a deep diversity analysis of bacterial communities in unvegetated arid soils of the Atacama Desert, to characterize community structure and infer the functional potential of these communities based on observed phylogenetic associations. A 454-pyrotag analysis was conducted of three unvegetated arid sites located at the hyperarid-arid margin. The analysis revealed communities with unique bacterial diversity marked by high abundances of novel Actinobacteria and Chloroflexi and low levels of Acidobacteria and Proteobacteria, phyla that are dominant in many biomes. A 16S rRNA gene library of one site revealed the presence of clones with phylogenetic associations to chemoautotrophic taxa able to obtain energy through oxidation of nitrite, carbon monoxide, iron, or sulfur. Thus, soils at the hyperarid margin were found to harbor a wealth of novel bacteria and to support potentially viable communities with phylogenetic associations to non-phototrophic primary producers and bacteria capable of biogeochemical cycling.

Life at the hyperarid margin: novel bacterial diversity in arid soils of the Atacama Desert, Chile.

Science.gov (United States)

Neilson, Julia W; Quade, Jay; Ortiz, Marianyoly; Nelson, William M; Legatzki, Antje; Tian, Fei; LaComb, Michelle; Betancourt, Julio L; Wing, Rod A; Soderlund, Carol A; Maier, Raina M

2012-05-01

Nearly half the earth's surface is occupied by dryland ecosystems, regions susceptible to reduced states of biological productivity caused by climate fluctuations. Of these regions, arid zones located at the interface between vegetated semiarid regions and biologically unproductive hyperarid zones are considered most vulnerable. The objective of this study was to conduct a deep diversity analysis of bacterial communities in unvegetated arid soils of the Atacama Desert, to characterize community structure and infer the functional potential of these communities based on observed phylogenetic associations. A 454-pyrotag analysis was conducted of three unvegetated arid sites located at the hyperarid-arid margin. The analysis revealed communities with unique bacterial diversity marked by high abundances of novel Actinobacteria and Chloroflexi and low levels of Acidobacteria and Proteobacteria, phyla that are dominant in many biomes. A 16S rRNA gene library of one site revealed the presence of clones with phylogenetic associations to chemoautotrophic taxa able to obtain energy through oxidation of nitrite, carbon monoxide, iron, or sulfur. Thus, soils at the hyperarid margin were found to harbor a wealth of novel bacteria and to support potentially viable communities with phylogenetic associations to non-phototrophic primary producers and bacteria capable of biogeochemical cycling.

Assessment of the Joint Development Potential of Wave and Wind Energy in the South China Sea

Directory of Open Access Journals (Sweden)

Yong Wan

2018-02-01

Full Text Available The South China Sea is a major shipping hub between the West Pacific and Indian Oceans. In this region, the demand for energy is enormous, both for residents’ daily lives and for economic development. Wave energy and wind energy are two major clean and low-cost ocean sources of renewable energy. The reasonable development and utilization of these energy sources can provide a stable energy supply for coastal cities and remote islands of China. Before wave energy and wind energy development, however, we must assess the potential of each of these sources. Based on high-resolution and high-accuracy wave field data and wind field data obtained by ERA-Interim reanalysis for the recent 38-year period from 1979–2016, the joint development potential of wave energy and wind energy was assessed in detail for offshore and nearshore areas in the South China Sea. Based on potential installed capacity, the results revealed three promising areas for the joint development of nearshore wave energy and wind energy, including the Taiwan Strait, Luzon Strait and the sea southeast of the Indo-China Peninsula. For these three dominant areas (key stations, the directionality of wave energy and wind energy propagation were good in various seasons; the dominant wave conditions and the dominant wind conditions were the same, which is advantageous for the joint development of wave and wind energy. Existing well-known wave energy converters (WECs are not suitable for wave energy development in the areas of interest. Therefore, we must consider the distributions of wave conditions and develop more suitable WECs for these areas. The economic and environmental benefits of the joint development of wave and wind energy are high in these promising areas. The results described in this paper can provide references for the joint development of wave and wind energy in the South China Sea.

Limits to benthic feeding by eiders in a vital Arctic migration corridor due to localized prey and changing sea ice

Science.gov (United States)

Lovvorn, James R.; Rocha, Aariel R.; Jewett, Stephen C.; Dasher, Douglas; Oppel, Steffen; Powell, Abby

2015-01-01

Four species of threatened or declining eider ducks that nest in the Arctic migrate through the northeast Chukchi Sea, where anticipated industrial development may require prioritizing areas for conservation. In this nearshore corridor (10–40 m depth), the eiders’ access to benthic prey during the spring is restricted to variable areas of open water within sea ice. For the most abundant species, the king eider (Somateria spectabilis), stable isotopes in blood cells, muscle, and potential prey indicate that these eiders ate mainly bivalves when traversing this corridor. Bivalves there were much smaller than the same taxa in deeper areas of the northern Bering Sea, possibly due to higher mortality rates caused by ice scour in shallow water; future decrease in seasonal duration of fast ice may increase this effect. Computer simulations suggested that if these eiders forage for >15 h/day, they can feed profitably at bivalve densities >200 m−2 regardless of water depth or availability of ice for resting. Sampling in 2010–2012 showed that large areas of profitable prey densities occurred only in certain locations throughout the migration corridor. Satellite data in April–May over 13 years (2001–2013) indicated that access to major feeding areas through sea ice in different segments of the corridor can vary from 0% to 100% between months and years. In a warming and increasingly variable climate, unpredictability of access may be enhanced by greater effects of shifting winds on unconsolidated ice. Our results indicate the importance of having a range of potential feeding areas throughout the migration corridor to ensure prey availability in all years. Spatial planning of nearshore industrial development in the Arctic, including commercial shipping, pipeline construction, and the risk of released oil, should consider these effects of high environmental variability on the adequacy of habitats targeted for conservation.

Application of State of Art Modeling Techniques to Predict Flooding and Waves for an Exposed Coastal Area

Directory of Open Access Journals (Sweden)

Malcolm L. Spaulding

2017-02-01

Full Text Available Flood Insurance Rate Maps (FIRMs are developed by the Federal Emergency Management Agency (FEMA to provide guidance in establishing the risk to structures and infrastructure in the coastal zone from storm surge and coincidental waves. The maps are used by state agencies and municipalities to help guide coastal planning and establish the minimum elevation standard for new or substantially improved structures. A summary of the methods used and results of 2012 FIRM mapping are presented for Charlestown, RI; a coastal community located along the exposed, southern shoreline of the state. Concerns with the methods used in the 2012 analysis are put in context with the National Research Council’s (NRC 2009 review of the FEMA coastal mapping program. New mapping is then performed using state of the art, fully coupled surge and wave modeling and data analysis methods to address the concerns in the NRC review. The new maps and methodologies are in compliance with FEMA regulations and guidelines. The approach makes extensive use of the numerical modeling results from the recent US Army Corp of Engineers (USACE, North Atlantic Coast Comprehensive Study (NACCS 2015. Revised flood maps are presented and compared with the 2012 FIRM map to provide insight into the differences. The new maps highlight the importance of developing better estimates of offshore surge dynamics and its coupling to waves, dune erosion based on local observations, and the advancement in nearshore mapping of waves in flood inundated areas by the use of state of the art, two-dimensional wave transformation models.

Crevasse Splays Versus Avulsions: A Recipe for Land Building With Levee Breaches

Science.gov (United States)

Nienhuis, Jaap H.; Törnqvist, Torbjörn E.; Esposito, Christopher R.

2018-05-01

Natural-levee breaches can not only initiate an avulsion but also, under the right circumstances, lead to crevasse splay formation and overbank sedimentation. The formative conditions for crevasse splays are not well understood, yet such river sediment diversions form an integral part of billion-dollar coastal restoration projects. Here we use Delft3D to investigate the influence of vegetation and soil consolidation on the evolution of a natural-levee breach. Model simulations show that crevasse splays heal because floodplain aggradation reduces the water surface slope, decreasing water discharge into the flood basin. Easily erodible and unvegetated floodplains increase the likelihood for channel avulsions. Denser vegetation and less potential for soil consolidation result in small crevasse splays that are not only efficient sediment traps but also short-lived. Successful crevasse splays that generate the largest land area gain for the imported sediment require a delicate balance between water and sediment discharge, vegetation root strength, and soil consolidation.

Using the value of Lin's concordance correlation coefficient as a criterion for efficient estimation of areas of leaves of eelgrass from noisy digital images.

Science.gov (United States)

Echavarría-Heras, Héctor; Leal-Ramírez, Cecilia; Villa-Diharce, Enrique; Castillo, Oscar

2014-01-01

Eelgrass is a cosmopolitan seagrass species that provides important ecological services in coastal and near-shore environments. Despite its relevance, loss of eelgrass habitats is noted worldwide. Restoration by replanting plays an important role, and accurate measurements of the standing crop and productivity of transplants are important for evaluating restoration of the ecological functions of natural populations. Traditional assessments are destructive, and although they do not harm natural populations, in transplants the destruction of shoots might cause undesirable alterations. Non-destructive assessments of the aforementioned variables are obtained through allometric proxies expressed in terms of measurements of the lengths or areas of leaves. Digital imagery could produce measurements of leaf attributes without the removal of shoots, but sediment attachments, damage infringed by drag forces or humidity contents induce noise-effects, reducing precision. Available techniques for dealing with noise caused by humidity contents on leaves use the concepts of adjacency, vicinity, connectivity and tolerance of similarity between pixels. Selection of an interval of tolerance of similarity for efficient measurements requires extended computational routines with tied statistical inferences making concomitant tasks complicated and time consuming. The present approach proposes a simplified and cost-effective alternative, and also a general tool aimed to deal with any sort of noise modifying eelgrass leaves images. Moreover, this selection criterion relies only on a single statistics; the calculation of the maximum value of the Concordance Correlation Coefficient for reproducibility of observed areas of leaves through proxies obtained from digital images. Available data reveals that the present method delivers simplified, consistent estimations of areas of eelgrass leaves taken from noisy digital images. Moreover, the proposed procedure is robust because both the optimal

Co-evolution of Riparian Vegetation and Channel Dynamics in an Aggrading Braided River System, Mount Pinatubo, Philippines

Science.gov (United States)

Gran, K. B.; Michal, T.

2014-12-01

Increased bank stability by riparian vegetation in braided rivers can decrease bed reworking rates and focus the flow. The magnitude of influence and resulting channel morphology are functions of vegetation strength vs. channel dynamics, a concept encapsulated in a dimensionless ratio between timescales for vegetation growth and channel reworking known as T*. We investigate this relationship in an aggrading braided river at Mount Pinatubo, Philippines, and compare results to numerical and physical models. Gradual reductions in post-eruption sediment loads have reduced bed reworking rates, allowing vegetation to persist year-round and impact channel dynamics on the Pasig-Potrero and Sacobia Rivers. From 2009-2011, we collected data detailing vegetation extent, type, density, and root strength. Incorporating these data into RipRoot and BSTEM models shows cohesion due to roots increased from zero in unvegetated conditions to >10.2 kPa in densely-growing grasses. Field-based parameters were incorporated into a cellular model comparing vegetation growth and sediment mobility effects on braided channel dynamics. The model shows that both low sediment mobility and high vegetation strength lead to less active systems, reflecting trends observed in the field. An estimated T* between 0.8 - 2.3 for the Pasig-Potrero River suggests channels were mobile enough to maintain the braidplain width clear of vegetation and even experience slight gains in area through annual removal of existing vegetation. However, persistent vegetation focused flow and thus aggradation over the unvegetated fraction of braidplain, leading to an aggradational imbalance and transition to a more avulsive state. While physical models predict continued narrowing of the active braidplain as T* declines, the future trajectory of channel-vegetation interactions at Pinatubo as sedimentation rates decline appears more complicated due to strong seasonal variability in precipitation and sediment loads. By 2011

Climate change-driven cliff and beach evolution at decadal to centennial time scales

Science.gov (United States)

Erikson, Li; O'Neill, Andrea; Barnard, Patrick; Vitousek, Sean; Limber, Patrick

2017-01-01

Here we develop a computationally efficient method that evolves cross-shore profiles of sand beaches with or without cliffs along natural and urban coastal environments and across expansive geographic areas at decadal to centennial time-scales driven by 21st century climate change projections. The model requires projected sea level rise rates, extrema of nearshore wave conditions, bluff recession and shoreline change rates, and cross-shore profiles representing present-day conditions. The model is applied to the ~470-km long coast of the Southern California Bight, USA, using recently available projected nearshore waves and bluff recession and shoreline change rates. The results indicate that eroded cliff material, from unarmored cliffs, contribute 11% to 26% to the total sediment budget. Historical beach nourishment rates will need to increase by more than 30% for a 0.25 m sea level rise (~2044) and by at least 75% by the year 2100 for a 1 m sea level rise, if evolution of the shoreline is to keep pace with rising sea levels.

Modeled sensitivity of Lake Michigan productivity and zooplankton to changing nutrient concentrations and quagga mussels

Science.gov (United States)

Pilcher, Darren J.; McKinley, Galen A.; Kralj, James; Bootsma, Harvey A.; Reavie, Euan D.

2017-08-01

The recent decline in Lake Michigan productivity is often attributed to filter feeding by invasive quagga mussels, but some studies also implicate reductions in lakewide nutrient concentrations. We use a 3-D coupled hydrodynamic-biogeochemical model to evaluate the effect of changing nutrient concentrations and quagga mussel filtering on phytoplankton production and phytoplankton and zooplankton biomass. Sensitivity experiments are used to assess the net effect of each change separately and in unison. Quagga mussels are found to have the greatest impact during periods of isothermal mixing, while nutrients have the greatest impact during thermal stratification. Quagga mussels also act to enhance spatial heterogeneity, particularly between nearshore-offshore regions. This effect produces a reversal in the gradient of nearshore-offshore productivity: from relatively greater nearshore productivity in the prequagga lake to relatively lesser nearshore productivity after quaggas. The combined impact of both processes drives substantial reductions in phytoplankton and zooplankton biomass, as well as significant modifications to the seasonality of surface water pCO2, particularly in nearshore regions where mussel grazing continues year-round. These results support growing concern that considerable losses of phytoplankton and zooplankton will yield concurrent losses at higher trophic levels. Comparisons to observed productivity suggest that both quagga mussel filtration and lower lakewide total phosphorus are necessary to accurately simulate recent changes in primary productivity in Lake Michigan.

Patterns in stable isotope values of nitrogen and carbon in particulate matter from the Northwest Atlantic Continental Shelf, from the Gulf of Maine to Cape Hatteras

Directory of Open Access Journals (Sweden)

Autumn Oczkowski

2016-12-01

Full Text Available Stable isotope measurements of nitrogen and carbon (δ15N, δ13C are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step towards developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter δ15N values ranged from 0.8 to 17.4 ‰, and δ13C values from -26.4 to -15.6 ‰ over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends towards lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher δ15N and δ13C values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the δ15N of subsurface and surface particulate matter (PM significantly increased with water depth (r2 = 0.41, df = 35, p < 0.001, while δ13C values did not change. There were significant positive correlation between δ15N and δ13C values for surface PM in each of the three marine ecoregions that make up the study area. Stable isotope dynamics on the shelf can inform both nearshore and open ocean research efforts, reflecting regional productivity patterns and, even possibly, large-scale climate fluctuations.

Archive of side scan sonar and swath bathymetry data collected during USGS cruise 10CCT03 offshore of the Gulf Islands National Seashore, Mississippi, from East Ship Island, Mississippi, to Dauphin Island, Alabama, April 2010

Science.gov (United States)

DeWitt, Nancy T.; Flocks, James G.; Pfeiffer, William R.; Gibson, James N.; Wiese, Dana S.

2012-01-01

In April of 2010, the U.S. Geological Survey (USGS) conducted a geophysical survey from the east end of East Ship Island, Miss., extending to the middle of Dauphin Island, Ala. (fig. 1). This survey had a dual purpose: (1) to interlink previously conducted nearshore geophysical surveys (shoreline to ~2 km) with those of offshore surveys (~2 to ~9 km) in the area, and (2) to extend the geophysical survey to include a portion of the Dauphin Island nearshore zone. The efforts were part of the USGS Gulf of Mexico Science Coordination partnership with the U.S. Army Corps of Engineers (USACE) to assist the Mississippi Coastal Improvements Program (MsCIP) and the Northern Gulf of Mexico (NGOM) Ecosystem Change and Hazards Susceptibility Project by mapping the shallow geological stratigraphic framework of the Mississippi Barrier Island Complex. These geophysical surveys will provide the data necessary for scientists to define, interpret, and provide baseline bathymetry and seafloor habitat for this area and to aid scientists in predicting future geomorpholocial changes of the islands with respect to climate change, storm impact, and sea-level rise. Furthermore, these data will provide information for barrier island restoration feasibility, particularly in Camille Cut, and efforts for the preservation of historical Fort Massachusetts. For more information refer to http://ngom.usgs.gov/gomsc/mscip/.

Detection and Classification of UXO Using Unmanned Undersea Electromagnetic Sensing Platforms

Science.gov (United States)

Schultz, G.; Keranen, J.; McNinch, J.; Miller, J.

2017-12-01

Important seafloor applications, including mine countermeasures, unexploded ordnance (UXO) surveys, salvage, and underwater hazards, require the detection, geo-registration, and characterization of man-made targets on, or below, the seafloor. Investigations in littoral environments can be time-consuming and expensive due to the challenges of accurately tracking underwater assets, the difficulty of quick or effective site reconnaissance activities, high levels of clutter in nearshore areas, and lack of situational awareness and real-time feedback to operators. Consequently, a high payoff exists for effective methods using sensor and data fusion, feature extraction, and effective payload integration and deployment for improved assessments of littoral infrastructure. We present technology development and demonstration results from multiple technology research, development, and demonstration projects over the last 3 years that have been focused on advancing seafloor target detection, tracking, and classification for specific environmental and defense missions. We focus on challenges overcome in integrating and testing new miniaturized passive magnetic and controlled-source electromagnetic sensors on a variety of remotely and autonomously operated sensing platforms (ROVs, AUVs and bottom crawling systems). In particular, we present aspects of the design, development, and testing of array configurations of miniaturized atomic magnetometers/gradiometers and multi-dimensional electromagnetic (EM) sensor arrays. Results from nearshore (surf zone and marsh in North Carolina) and littoral experiments (bays and reef areas of Florida Gulf and Florida Keys) are presented.

Factors associated with the deposition of Cladophora on Lake Michigan beaches in 2012

Science.gov (United States)

Riley, Stephen C.; Tucker, Taaja R.; Adams, Jean V.; Fogarty, Lisa R.; Lafrancois, Brenda Moraska

2015-01-01

Deposition of the macroalgae Cladophora spp. was monitored on 18 beaches around Lake Michigan during 2012 at a high temporal frequency. We observed a high degree of spatial variability in Cladophora deposition among beaches on Lake Michigan, even within local regions, with no clear regional pattern in the intensity of Cladophora deposition. A strong seasonal pattern in Cladophora deposition was observed, with the heaviest deposition occurring during mid-summer. Several beaches exhibited high temporal variability in Cladophora deposition over short time scales, suggesting that drifting algal mats may be extremely dynamic in nearshore environments of the Great Lakes. Cladophora deposition on Lake Michigan beaches was primarily related to the presence of nearshore structures, local population density, and nearshore bathymetry. There was relatively little evidence that waves, winds, or currents were associated with Cladophora deposition on beaches, but this may be due to the relatively poor resolution of existing nearshore hydrodynamic data. Developing a predictive understanding of beach-cast Cladophora dynamics in Great Lakes environments may require both intensive Cladophora monitoring and fine-scale local hydrodynamic modeling efforts.

Geomorphometry in coastal morphodynamics

Science.gov (United States)

Guisado-Pintado, Emilia; Jackson, Derek

2017-04-01

Geomorphometry is a cross-cutting discipline that has interwoven itself into multiple research themes due to its ability to encompass topographic quantification on many fronts. Its operational focus is largely defined as the extraction of land-surface parameters and earth surface characterisation. In particular, the coastal sciences have been enriched by the use of digital terrain production techniques both on land and in the nearshore/marine area. Numerous examples exist in which the utilisation of field instrumentation (e.g. LIDAR, GPS, Terrestrial Laser Scanning, multi-beam echo-sounders) are used for surface sampling and development of Digital Terrain Models, monitoring topographic change and creation of nearshore bathymetry, and have become central elements in modern investigations of coastal morphodynamics. The coastal zone is a highly dynamic system that embraces variable and at times, inter-related environments (sand dunes, sandy beaches, shoreline and nearshore) all of which require accurate and integrated monitoring. Although coastal studies can be widely diverse (with interconnected links to other related disciplines such as geology or biology), the characterisation of the landforms (coastal geomorphology) and associated processes (morphodynamics, hydrodynamics, aeolian processes) is perhaps where geomorphometry (topo-bathymetry quantification) is best highlighted. In this respect, many tools have been developed (or improved upon) for the acquisition of topographic data that now commands a high degree of accuracy, simplicity, and ultimately acquisition cost reduction. We present a series of field data acquisitions examples that have produced land surface characterisation using a range of techniques including traditional GPS surveys to more recent Terrestrial Laser Scanning and airborne LIDAR. These have been conducted within beach and dune environments and have helped describe erosion and depositional processes driven by wind and wave energy (high

Transport of Gas and Solutes in Permeable Estuarine Sediments

Science.gov (United States)

2013-09-30

Sea to Coast Connectivity in the Eastern Gulf of Mexico ” $203,471 (Huettel funds), E. Chassignet (PI), M. Huettel (one of several Co-PIs), we...However, in many shelf areas the depth, sufficient light reaching the sea floor will likely be less than 25 m due to water turbidity . The water in our...biogeochemical reactions. As crude oil from the recent oil spill in the Gulf and phytoplankton affect the sediment in the shallow nearshore zone, this project is

Design and analysis of a semi-submersible vertical axis wind turbine

OpenAIRE

Siddique, Muhammad Abu Zafar

2017-01-01

Wind energy are deployed by two types of wind turbines. They are Horizontal Axis Wind Turbine (HAWT) and Vertical Axis Wind Turbine (VAWT), classified according to their axis of rotation. In recent years, offshore wind energy playing a vital role in the wind turbine industry due to high intensity of air, less turbulent and comparatively clean and easily employed in large area which is difficult to manage for onshore or near-shore. The advantages of HAWTs are now facing different challenge in ...

The attached algae community near Pickering GS: III

International Nuclear Information System (INIS)

McKinley, S.R.

1982-01-01

The relationship between attached algae and macro-invertebrates in the nearshore zone of Lake Ontario was investigated in the vicinity of the Pickering 'A' NGS. Measures of faunal density, richness, evenness, and biomass were generally higher from areas which supported attached algae. Gammarus fasciatus, Cricotopus bicinctus, Dicrotendipes spp., Orthocladius obumbratus, Cladotanytarsus spp., Orthocladius spp., and Parakiefferiella spp., were significantly correlated with algal standing crop. All of the above dominant invertebrates ingested epiphytes associated with Cladophora glomerata. Attempts to explain the distribution of the zoobenthic assemblages using the physical/biological characteristics of the study area indicated algal cover, substrate size, wind velocity and water temperature were most important

Erodibility of surface-mine spoil banks in southeastern Ohio : an approximation

Energy Technology Data Exchange (ETDEWEB)

McKenzie, C D; Studlick, J R.J.

1979-07-01

Measurements of accumulated sediment in inter-bank basins of unreclaimed strip mines determined the average annual site loss from unvegetated, 18-year-old spoil banks. Assuming that the universal soil loss equation (USLE) can be used to estimate sediment yield from strip mine slopes, the topographic factor in the USLE was determined in 2 ways, and values for erodibility well calculated. The technique is applicable to unreclaimed mines where inter-bank basins trap all slope-derived sediment.

Flow area optimization in point to area or area to point flows

International Nuclear Information System (INIS)

Ghodoossi, Lotfollah; Egrican, Niluefer

2003-01-01

This paper deals with the constructal theory of generation of shape and structure in flow systems connecting one point to a finite size area. The flow direction may be either from the point to the area or the area to the point. The formulation of the problem remains the same if the flow direction is reversed. Two models are used in optimization of the point to area or area to point flow problem: cost minimization and revenue maximization. The cost minimization model enables one to predict the shape of the optimized flow areas, but the geometric sizes of the flow areas are not predictable. That is, as an example, if the area of flow is a rectangle with a fixed area size, optimization of the point to area or area to point flow problem by using the cost minimization model will only predict the height/length ratio of the rectangle not the height and length itself. By using the revenue maximization model in optimization of the flow problems, all optimized geometric aspects of the interested flow areas will be derived as well. The aim of this paper is to optimize the point to area or area to point flow problems in various elemental flow area shapes and various structures of the flow system (various combinations of elemental flow areas) by using the revenue maximization model. The elemental flow area shapes used in this paper are either rectangular or triangular. The forms of the flow area structure, made up of an assembly of optimized elemental flow areas to obtain bigger flow areas, are rectangle-in-rectangle, rectangle-in-triangle, triangle-in-triangle and triangle-in-rectangle. The global maximum revenue, revenue collected per unit flow area and the shape and sizes of each flow area structure have been derived in optimized conditions. The results for each flow area structure have been compared with the results of the other structures to determine the structure that provides better performance. The conclusion is that the rectangle-in-triangle flow area structure

Geological survey of Maryland using EREP flight data. [mining, mapping, Chesapeake Bay islands, coastal water features

Science.gov (United States)

Weaver, K. N. (Principal Investigator)

1973-01-01

The author has identified the following significant results. Underflight photography has been used in the Baltimore County mined land inventory to determine areas of disturbed land where surface mining of sand and ground clay, or stone has taken place. Both active and abandoned pits and quarries were located. Aircraft data has been used to update cultural features of Calvert, Caroline, St. Mary's, Somerset, Talbot, and Wicomico Counties. Islands have been located and catalogued for comparison with older film and map data for erosion data. Strip mined areas are being mapped to obtain total area disturbed to aid in future mining and reclamation problems. Coastal estuarine and Atlantic Coast features are being studied to determine nearshore bedforms, sedimentary, and erosional patterns, and manmade influence on natural systems.

Assessment of Nearshore Hazard due to Tsunami-Induced Currents

Science.gov (United States)

Lynett, P. J.; Ayca, A.; Borrero, J. C.; Eskijian, M.; Miller, K.; Wilson, R. I.

2014-12-01

The California Tsunami Program in cooperation with NOAA and FEMA has begun implementing a plan to increase tsunami hazard preparedness and mitigation in maritime communities (both ships and harbor infrastructure) through the development of in-harbor hazard maps, offshore safety zones for boater evacuation, and associated guidance for harbors and marinas before, during and following tsunamis. The hope is that the maritime guidance and associated education program will help save lives and reduce exposure of damage to boats and harbor infrastructure. Findings will be used to develop maps, guidance documents, and consistent policy recommendations for emergency managers and port authorities and provide information critical to real-time decisions required when responding to tsunami alert notifications. The initial goals of the study are to (1) evaluate the effectiveness and sensitivity of existing numerical models for assessing maritime tsunami hazards, (2) find a relationship between current speeds and expected damage levels, (3) evaluate California ports and harbors in terms of tsunami induced hazards by identifying regions that are prone to higher current speeds and damage and to identify regions of relatively lower impact that may be used for evacuation of maritime assets, and (4) determine 'safe depths' for evacuation of vessels from ports and harbors during a tsunami event. We will present details of a new initiative to evaluate the future likelihood of failure for different structural components of a harbor, leading to the identification of high priority areas for mitigation. This presentation will focus on the results from California ports and harbors across the State, and will include feedback we have received from discussions with local harbor masters and port authorities. To help promote accurate and consistent products, the authors are also working through the National Tsunami Hazard Mitigation Program to organize a tsunami current model benchmark workshop.

Spatio-temporal scaling effects on longshore sediment transport pattern along the nearshore zone

Science.gov (United States)

Khorram, Saeed; Ergil, Mustafa

2018-03-01

A measure of uncertainties, entropy has been employed in such different applications as coastal engineering probability inferences. Entropy sediment transport integration theories present novel visions in coastal analyses/modeling the application and development of which are still far-reaching. Effort has been made in the present paper to propose a method that needs an entropy-power index for spatio-temporal patterns analyses. Results have shown that the index is suitable for marine/hydrological ecosystem components analyses based on a beach area case study. The method makes use of six Makran Coastal monthly data (1970-2015) and studies variables such as spatio-temporal patterns, LSTR (long-shore sediment transport rate), wind speed, and wave height all of which are time-dependent and play considerable roles in terrestrial coastal investigations; the mentioned variables show meaningful spatio-temporal variability most of the time, but explanation of their combined performance is not easy. Accordingly, the use of an entropy-power index can show considerable signals that facilitate the evaluation of water resources and will provide an insight regarding hydrological parameters' interactions at scales as large as beach areas. Results have revealed that an STDDPI (entropy based spatio-temporal disorder dynamics power index) can simulate wave, long-shore sediment transport rate, and wind when granulometry, concentration, and flow conditions vary.

Interannual and seasonal variations in nearshore wave characteristics off Honnavar, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Sanjiv, P.C.; SanilKumar, V.; Johnson, G.; Dora, G.U.; Vinayaraj, P.

obtained for the point (12.5°N; 72.5°E) close to the study area to know the influence of wind on waves. These data are provided by the NOAA–CIRES Climate Diagnostics Center, Boulder, Colarado, USA at http://www.cdc.noaa. gov/. Results and discussion...

Estimates of Nutrient Loading by Ground-Water Discharge into the Lynch Cove Area of Hood Canal, Washington

Science.gov (United States)

Simonds, F. William; Swarzenski, Peter W.; Rosenberry, Donald O.; Reich, Christopher D.; Paulson, Anthony J.

2008-01-01

Low dissolved oxygen concentrations in the waters of Hood Canal threaten marine life in late summer and early autumn. Oxygen depletion in the deep layers and landward reaches of the canal is caused by decomposition of excess phytoplankton biomass, which feeds on nutrients (primarily nitrogen compounds) that enter the canal from various sources, along with stratification of the water column that prevents mixing and replenishment of oxygen. Although seawater entering the canal is the largest source of nitrogen, ground-water discharge to the canal also contributes significant quantities, particularly during summer months when phytoplankton growth is most sensitive to nutrient availability. Quantifying ground-water derived nutrient loads entering an ecologically sensitive system such as Hood Canal is a critical component of constraining the total nutrient budget and ultimately implementing effective management strategies to reduce impacts of eutrophication. The amount of nutrients entering Hood Canal from ground water was estimated using traditional and indirect measurements of ground-water discharge, and analysis of nutrient concentrations. Ground-water discharge to Hood Canal is variable in space and time because of local geology, variable hydraulic gradients in the ground-water system adjacent to the shoreline, and a large tidal range of 3 to 5 meters. Intensive studies of ground-water seepage and hydraulic-head gradients in the shallow, nearshore areas were used to quantify the freshwater component of submarine ground-water discharge (SGD), whereas indirect methods using radon and radium geochemical tracers helped quantify total SGD and recirculated seawater. In areas with confirmed ground-water discharge, shore-perpendicular electrical resistivity profiles, continuous electromagnetic seepage-meter measurements, and continuous radon measurements were used to visualize temporal variations in ground-water discharge over several tidal cycles. The results of these

DETECTION OF COASTLINE DEFORMATION USING REMOTE SENSING AND GEODETIC SURVEYS

Directory of Open Access Journals (Sweden)

A. Sabuncu

2016-06-01

Full Text Available The coastal areas are being destroyed due to the usage that effect the natural balance. Unconsciously sand mining from the sea for nearshore nourishment and construction uses are the main ones. Physical interferences for mining of sand cause an ecologic threat to the coastal environment. However, use of marine sand is inevitable because of economic reasons or unobtainable land-based sand resources. The most convenient solution in such a protection–usage dilemma is to reduce negative impacts of sand production from marine. This depends on the accurate determination of criteriaon production place, style, and amount of sand. With this motivation, nearshore geodedic surveying studies performed on Kilyos Campus of Bogazici University located on the Black Sea coast, north of Istanbul, Turkey between 2001-2002. The study area extends 1 km in the longshore. Geodetic survey was carried out in the summer of 2001 to detect the initial condition for the shoreline. Long-term seasonal changes in shoreline positions were determined biannually. The coast was measured with post-processed kinematic GPS. Besides, shoreline change has studied using Landsat imagery between the years 1986-2015. The data set of Landsat 5 imageries were dated 05.08.1986 and 31.08.2007 and Landsat 7 imageries were dated 21.07.2001 and 28.07.2015. Landcover types in the study area were analyzed on the basis of pixel based classification method. Firstly, unsupervised classification based on ISODATA (Iterative Self Organizing Data Analysis Technique has been applied and spectral clusters have been determined that gives prior knowledge about the study area. In the second step, supervised classification was carried out by using the three different approaches which are minimum-distance, parallelepiped and maximum-likelihood. All pixel based classification processes were performed with ENVI 4.8 image processing software. Results of geodetic studies and classification outputs will be

Sources of nutrients to nearshore areas of a eutrophic estuary: Implications for nutrient-enhanced acidification in Puget Sound

Science.gov (United States)

Ocean acidification has recently been highlighted as a major stressor for coastal organisms. Further work is needed to assess the role of anthropogenic nutrient additions in eutrophied systems on local biological processes, and how this interacts with CO2emission-driven acidific...

Longshore currents and associated sediment transport in the nearshore areas of Kerala and Goa, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Murty, C.S.; Veerayya, M.

The field observations on the longshore currents at selected locations along the coasts of Goa and Kerala on the western seaboard spanning over a period of five years revealed high variability in their direction and speed. The currents...

Consequences of least tern (Sternula antillarum) microhabitat nest-site selection on natural and mechanically constructed sandbars in the Missouri River

Science.gov (United States)

Stucker, Jennifer H.; Buhl, Deborah A.; Sherfy, Mark H.

2013-01-01

Nest-habitat selection in colonial species has rarely been assessed at multiple spatial scales to evaluate its fitness consequences. Management for the federally endangered U.S. Interior population of Least Terns (Sternula antillarum) has focused on maintenance of breeding habitats, including mechanical construction of sandbars from dredged material. Least Terns are attracted to large areas of unvegetated substrate, yet small-scale habitat features are thought to trigger selection for nesting. We evaluated nest-scale habitat selection to determine (1) whether selection differs between constructed and natural sandbars and (2) the subsequent consequences of habitat selection on nest success. During 2006–2008, we examined 869 Least Tern nest sites on constructed and natural sandbars in the Missouri River for evidence of microhabitat selection at the nest in relation to habitat within the surrounding 3-m area. Least Tern nest sites had coarser and larger substrate materials at the nest, more debris, and less vegetation than the surrounding area. Nests in constructed habitats had a greater percentage of coarse substrates and less vegetation or debris than nests in naturally created habitats. Apparent nest success was 1.8× greater on constructed than on natural sandbars. Nest success was best predicted by models with two spatial scales of predictors, including substrates (nest) and vegetation and debris (nest or surrounding area). Our results indicate that Least Terns select nest microhabitat characteristics that are associated with wind- and water-scoured habitats, and that nest success increases when these habitats are selected.

Status and trends in the fish community of Lake Superior, 2012

Science.gov (United States)

Gorman, Owen T.; Evrard, Lori M.; Cholwek, Gary A.; Vinson, Mark

2012-01-01

The Great Lakes Science Center has conducted daytime nearshore bottom trawl surveys of Lake Superior (15-80 m bathymetric depth zone) each spring since 1978 and an offshore survey (>80 m) since 2011 to provide long-term trends of relative abundance and biomass of the fish community. In 2012, 72 nearshore and 34 offshore stations were sampled with a 12-m Yankee bottom trawl.

Extended abstracts from the Coastal Habitats in Puget Sound (CHIPS) 2006 Workshop

Science.gov (United States)

Gelfenbaum, Guy R.; Fuentes, Tracy L.; Duda, Jeffrey J.; Grossman, Eric E.; Takesue, Renee K.

2010-01-01

Puget Sound is the second largest estuary in the United States. Its unique geology, climate, and nutrient-rich waters produce and sustain biologically productive coastal habitats. These same natural characteristics also contribute to a high quality of life that has led to a significant growth in human population and associated development. This population growth, and the accompanying rural and urban development, has played a role in degrading Puget Sound ecosystems, including declines in fish and wildlife populations, water-quality issues, and loss and degradation of coastal habitats.In response to these ecosystem declines and the potential for strategic large-scale preservation and restoration, a coalition of local, State, and Federal agencies, including the private sector, Tribes, and local universities, initiated the Puget Sound Nearshore Ecosystem Restoration Project (PSNERP). The Nearshore Science Team (NST) of PSNERP, along with the U.S. Geological Survey, developed a Science Strategy and Research Plan (Gelfenbaum and others, 2006) to help guide science activities associated with nearshore ecosystem restoration. Implementation of the Research Plan includes a call for State and Federal agencies to direct scientific studies to support PSNERP information needs. In addition, the overall Science Strategy promotes greater communication with decision makers and dissemination of scientific results to the broader scientific community.On November 14–16, 2006, the U.S. Geological Survey sponsored an interdisciplinary Coastal Habitats in Puget Sound (CHIPS) Research Workshop at Fort Worden State Park, Port Townsend, Washington. The main goals of the workshop were to coordinate, integrate, and link research on the nearshore of Puget Sound. Presented research focused on three themes: (1) restoration of large river deltas; (2) recovery of the nearshore ecosystem of the Elwha River; and (3) effects of urbanization on nearshore ecosystems. The more than 35 presentations

A Multitracer Approach to Detecting Wastewater Plumes from Municipal Injection Wells in Nearshore Marine Waters at Kihei and Lahaina, Maui, Hawaii

Science.gov (United States)

Hunt, Charles D.; Rosa, Sarah N.

2009-01-01

Municipal wastewater plumes discharging from aquifer to ocean were detected by nearshore wading surveys at Kihei and Lahaina, on the island of Maui in Hawaii. Developed in cooperation with the Hawaii State Department of Health, the survey methodology included instrument trolling to detect submarine groundwater discharge, followed by analysis of water and macroalgae for a suite of chemical and isotopic constituents that constitute a 'multitracer' approach. Surveys were conducted May 6-28, 2008, during fair-weather conditions and included: (1) wading and kayak trolling with a multiparameter water-quality sonde, (2) marine water-column sampling, and (3) collection of benthic algae samples. Instrument trolling helped guide the water sampling strategy by providing dense, continuous transects of water properties on which groundwater discharge zones could be identified. Water and algae samples for costly chemical and isotopic laboratory analyses were last to be collected but were highly diagnostic of wastewater presence and nutrient origin because of low detection levels and confirmation across multiple tracers. Laboratory results confirmed the presence of wastewater constituents in marine water-column samples at both locales and showed evidence of modifying processes such as denitrification and mixing of effluent with surrounding groundwater and seawater. Carbamazepine was the most diagnostic pharmaceutical, detected in several marine water-column samples and effluent at both Kihei and Lahaina. Heavy nitrogen-isotope compositions in water and algae were highly diagnostic of effluent, particularly where enriched to even heavier values than effluent source compositions by denitrification. Algae provided an added advantage of time-integrating their nitrogen source during growth. The measured Kihei plume coincided almost exactly with prior model predictions, but the Lahaina plume was detected well south of the expected direct path from injection wells to shore and may be

Fish with Chips: Tracking Reef Fish Movements to Evaluate Size and Connectivity of Caribbean Marine Protected Areas

Science.gov (United States)

Pittman, Simon J.; Monaco, Mark E.; Friedlander, Alan M.; Legare, Bryan; Nemeth, Richard S.; Kendall, Matthew S.; Poti, Matthew; Clark, Randall D.; Wedding, Lisa M.; Caldow, Chris

2014-01-01

Coral reefs and associated fish populations have experienced rapid decline in the Caribbean region and marine protected areas (MPAs) have been widely implemented to address this decline. The performance of no-take MPAs (i.e., marine reserves) for protecting and rebuilding fish populations is influenced by the movement of animals within and across their boundaries. Very little is known about Caribbean reef fish movements creating a critical knowledge gap that can impede effective MPA design, performance and evaluation. Using miniature implanted acoustic transmitters and a fixed acoustic receiver array, we address three key questions: How far can reef fish move? Does connectivity exist between adjacent MPAs? Does existing MPA size match the spatial scale of reef fish movements? We show that many reef fishes are capable of traveling far greater distances and in shorter duration than was previously known. Across the Puerto Rican Shelf, more than half of our 163 tagged fish (18 species of 10 families) moved distances greater than 1 km with three fish moving more than 10 km in a single day and a quarter spending time outside of MPAs. We provide direct evidence of ecological connectivity across a network of MPAs, including estimated movements of more than 40 km connecting a nearshore MPA with a shelf-edge spawning aggregation. Most tagged fish showed high fidelity to MPAs, but also spent time outside MPAs, potentially contributing to spillover. Three-quarters of our fish were capable of traveling distances that would take them beyond the protection offered by at least 40–64% of the existing eastern Caribbean MPAs. We recommend that key species movement patterns be used to inform and evaluate MPA functionality and design, particularly size and shape. A re-scaling of our perception of Caribbean reef fish mobility and habitat use is imperative, with important implications for ecology and management effectiveness. PMID:24797815

Fish with chips: tracking reef fish movements to evaluate size and connectivity of Caribbean marine protected areas.

Directory of Open Access Journals (Sweden)

Simon J Pittman

Full Text Available Coral reefs and associated fish populations have experienced rapid decline in the Caribbean region and marine protected areas (MPAs have been widely implemented to address this decline. The performance of no-take MPAs (i.e., marine reserves for protecting and rebuilding fish populations is influenced by the movement of animals within and across their boundaries. Very little is known about Caribbean reef fish movements creating a critical knowledge gap that can impede effective MPA design, performance and evaluation. Using miniature implanted acoustic transmitters and a fixed acoustic receiver array, we address three key questions: How far can reef fish move? Does connectivity exist between adjacent MPAs? Does existing MPA size match the spatial scale of reef fish movements? We show that many reef fishes are capable of traveling far greater distances and in shorter duration than was previously known. Across the Puerto Rican Shelf, more than half of our 163 tagged fish (18 species of 10 families moved distances greater than 1 km with three fish moving more than 10 km in a single day and a quarter spending time outside of MPAs. We provide direct evidence of ecological connectivity across a network of MPAs, including estimated movements of more than 40 km connecting a nearshore MPA with a shelf-edge spawning aggregation. Most tagged fish showed high fidelity to MPAs, but also spent time outside MPAs, potentially contributing to spillover. Three-quarters of our fish were capable of traveling distances that would take them beyond the protection offered by at least 40-64% of the existing eastern Caribbean MPAs. We recommend that key species movement patterns be used to inform and evaluate MPA functionality and design, particularly size and shape. A re-scaling of our perception of Caribbean reef fish mobility and habitat use is imperative, with important implications for ecology and management effectiveness.

Mechanics of dispersion of pollutants in coastal environment

International Nuclear Information System (INIS)

Jordaan, J.M. Jr.

1973-01-01

The relationships between energy dissipation (turbulence) and mixing and analogy with classical diffusion theory are reviewed. Typical solutions of the differential equations, for various initial and boundary conditions related to practical cases are presented. The natural processes that control the dispersion in the nearshore regions were studied in a wind-wave channel and in the field and interpretive conclusions are drawn on the practice of nearshore disposal of effluents

Regional Sediment Management Strategies for the Vicinity of St. Augustine Inlet, St. Johns County, Florida

Science.gov (United States)

2016-07-01

Placement): Hopper dredge can dump in nearshore or use beach pump -out capabilities (if available). Pipeline dredge can dredge from all permitted sources... dump in nearshore or use beach pump -out capabilities (if available). Pipeline dredge can dredge from all permitted sources with direct beach placement...direct pump -out to the beach. Concerns related to overdredging the ebb shoal were lessened since that source would be the final target, providing only

Hydrodynamic and Ecological Assessment of Nearshore Restoration: A Modeling Study

International Nuclear Information System (INIS)

Yang, Zhaoqing; Sobocinski, Kathryn L.; Heatwole, Danelle W.; Khangaonkar, Tarang; Thom, Ronald M.; Fuller, Roger

2010-01-01

Along the Pacific Northwest coast, much of the estuarine habitat has been diked over the last century for agricultural land use, residential and commercial development, and transportation corridors. As a result, many of the ecological processes and functions have been disrupted. To protect coastal habitats that are vital to aquatic species, many restoration projects are currently underway to restore the estuarine and coastal ecosystems through dike breaches, setbacks, and removals. Information on physical processes and hydrodynamic conditions are critical for the assessment of the success of restoration actions. Restoration of a 160- acre property at the mouth of the Stillaguamish River in Puget Sound has been proposed. The goal is to restore native tidal habitats and estuary-scale ecological processes by removing the dike. In this study, a three-dimensional hydrodynamic model was developed for the Stillaguamish River estuary to simulate estuarine processes. The model was calibrated to observed tide, current, and salinity data for existing conditions and applied to simulate the hydrodynamic responses to two restoration alternatives. Responses were evaluated at the scale of the restoration footprint. Model data was combined with biophysical data to predict habitat responses at the site. Results showed that the proposed dike removal would result in desired tidal flushing and conditions that would support four habitat types on the restoration footprint. At the estuary scale, restoration would substantially increase the proportion of area flushed with freshwater (< 5 ppt) at flood tide. Potential implications of predicted changes in salinity and flow dynamics are discussed relative to the distribution of tidal marsh habitat.

Developmental and spatial variations in the diet signatures of hyperbenthic shrimp Nauticaris marionis at the Prince Edward Islands based on stable isotope ratios and fatty acid profiles

Science.gov (United States)

Richoux, Nicole B.; Allan, E. Louise; Froneman, P. William

2016-04-01

The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.

Inter-nesting movements and habitat-use of adult female Kemp’s ridley turtles in the Gulf of Mexico

Science.gov (United States)

Shaver, Donna J.; Hart, Kristen M.; Fujisaki, Ikuko; Bucklin, David N.; Iverson, Autumn; Rubio, Cynthia; Backof, Thomas F.; Burchfield, Patrick M.; Gonzales Diaz Miron, Raul de Jesus; Dutton, Peter H.; Frey, Amy; Peña, Jaime; Gamez, Daniel Gomez; Martinez, Hector J.; Ortiz, Jaime

2017-01-01

Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM) were used to define inter-nesting habitat of endangered Kemp’s ridley turtles (Lepidochelys kempii) in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60); Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11); and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11). These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp’s ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it.

Variability in metagenomic samples from the Puget Sound: Relationship to temporal and anthropogenic impacts.

Directory of Open Access Journals (Sweden)

James C Wallace

Full Text Available Whole-metagenome sequencing (WMS has emerged as a powerful tool to assess potential public health risks in marine environments by measuring changes in microbial community structure and function in uncultured bacteria. In addition to monitoring public health risks such as antibiotic resistance determinants, it is essential to measure predictors of microbial variation in order to identify natural versus anthropogenic factors as well as to evaluate reproducibility of metagenomic measurements.This study expands our previous metagenomic characterization of Puget Sound by sampling new nearshore environments including the Duwamish River, an EPA superfund site, and the Hood Canal, an area characterized by highly variable oxygen levels. We also resampled a wastewater treatment plant, nearshore and open ocean sites introducing a longitudinal component measuring seasonal and locational variations and establishing metagenomics sampling reproducibility. Microbial composition from samples collected in the open sound were highly similar within the same season and location across different years, while nearshore samples revealed multi-fold seasonal variation in microbial composition and diversity. Comparisons with recently sequenced predominant marine bacterial genomes helped provide much greater species level taxonomic detail compared to our previous study. Antibiotic resistance determinants and pollution and detoxification indicators largely grouped by location showing minor seasonal differences. Metal resistance, oxidative stress and detoxification systems showed no increase in samples proximal to an EPA superfund site indicating a lack of ecosystem adaptation to anthropogenic impacts. Taxonomic analysis of common sewage influent families showed a surprising similarity between wastewater treatment plant and open sound samples suggesting a low-level but pervasive sewage influent signature in Puget Sound surface waters. Our study shows reproducibility of

Recent salmon declines: a result of lost feeding opportunities due to bad timing?

Directory of Open Access Journals (Sweden)

Cedar M Chittenden

Full Text Available As the timing of spring productivity blooms in near-shore areas advances due to warming trends in global climate, the selection pressures on out-migrating salmon smolts are shifting. Species and stocks that leave natal streams earlier may be favoured over later-migrating fish. The low post-release survival of hatchery fish during recent years may be in part due to static release times that do not take the timing of plankton blooms into account. This study examined the effects of release time on the migratory behaviour and survival of wild and hatchery-reared coho salmon (Oncorhynchus kisutch using acoustic and coded-wire telemetry. Plankton monitoring and near-shore seining were also conducted to determine which habitat and food sources were favoured. Acoustic tags (n = 140 and coded-wire tags (n = 266,692 were implanted into coho salmon smolts at the Seymour and Quinsam Rivers, in British Columbia, Canada. Differences between wild and hatchery fish, and early and late releases were examined during the entire lifecycle. Physiological sampling was also carried out on 30 fish from each release group. The smolt-to-adult survival of coho salmon released during periods of high marine productivity was 1.5- to 3-fold greater than those released both before and after, and the fish's degree of smoltification affected their downstream migration time and duration of stay in the estuary. Therefore, hatchery managers should consider having smolts fully developed and ready for release during the peak of the near-shore plankton blooms. Monitoring chlorophyll a levels and water temperature early in the spring could provide a forecast of the timing of these blooms, giving hatcheries time to adjust their release schedule.

Inter-nesting movements and habitat-use of adult female Kemp's ridley turtles in the Gulf of Mexico.

Directory of Open Access Journals (Sweden)

Donna J Shaver

Full Text Available Species vulnerability is increased when individuals congregate in restricted areas for breeding; yet, breeding habitats are not well defined for many marine species. Identification and quantification of these breeding habitats are essential to effective conservation. Satellite telemetry and switching state-space modeling (SSM were used to define inter-nesting habitat of endangered Kemp's ridley turtles (Lepidochelys kempii in the Gulf of Mexico. Turtles were outfitted with satellite transmitters after nesting at Padre Island National Seashore, Texas, USA, from 1998 through 2013 (n = 60; Rancho Nuevo, Tamaulipas, Mexico, during 2010 and 2011 (n = 11; and Tecolutla, Veracruz, Mexico, during 2012 and 2013 (n = 11. These sites span the range of nearly all nesting by this species. Inter-nesting habitat lies in a narrow band of nearshore western Gulf of Mexico waters in the USA and Mexico, with mean water depth of 14 to 19 m within a mean distance to shore of 6 to 11 km as estimated by 50% kernel density estimate, α-Hull, and minimum convex polygon methodologies. Turtles tracked during the inter-nesting period moved, on average, 17.5 km/day and a mean total distance of 398 km. Mean home ranges occupied were 725 to 2948 km2. Our results indicate that these nearshore western Gulf waters represent critical inter-nesting habitat for this species, where threats such as shrimp trawling and oil and gas platforms also occur. Up to half of all adult female Kemp's ridleys occupy this habitat for weeks to months during each nesting season. Because inter-nesting habitat for this species is concentrated in nearshore waters of the western Gulf of Mexico in both Mexico and the USA, international collaboration is needed to protect this essential habitat and the turtles occurring within it.

Distribution and sediment production of large benthic foraminifers on reef flats of the Majuro Atoll, Marshall Islands

Science.gov (United States)

Fujita, K.; Osawa, Y.; Kayanne, H.; Ide, Y.; Yamano, H.

2009-03-01

The distributions and population densities of large benthic foraminifers (LBFs) were investigated on reef flats of the Majuro Atoll, Marshall Islands. Annual sediment production by foraminifers was estimated based on population density data. Predominant LBFs were Calcarina and Amphistegina, and the population densities of these foraminifers varied with location and substratum type on reef flats. Both foraminifers primarily attached to macrophytes, particularly turf-forming algae, and were most abundant on an ocean reef flat (ORF) and in an inter-island channel near windward, sparsely populated islands. Calcarina density was higher on windward compared to leeward sides of ORFs, whereas Amphistegina density was similar on both sides of ORFs. These foraminifers were more common on the ocean side relative to the lagoon side of reef flats around a windward reef island, and both were rare or absent in nearshore zones around reef islands and on an ORF near windward, densely populated islands. Foraminiferal production rates varied with the degree to which habitats were subject to water motion and human influences. Highly productive sites (>103 g CaCO3 m-2 year-1) included an ORF and an inter-island channel near windward, sparsely populated islands, and a seaward area of a reef flat with no reef islands. Low-productivity sites (<10 g CaCO3 m-2 year-1) included generally nearshore zones of lagoonal reef flats, leeward ORFs, and a windward ORF near densely populated islands. These results suggest that the distribution and production of LBFs were largely influenced by a combination of natural environmental factors, including water motion, water depth, elevation relative to the lowest tidal level at spring tide, and the distribution of suitable substratum. The presence of reef islands may limit the distribution and production of foraminifers by altering water circulation in nearshore environments. Furthermore, increased anthropogenic factors (population and activities) may

Fisheries Oceanography in the Virgin Islands: Preliminary Results from a Collaborative Research Endeavor

Science.gov (United States)

Smith, R. H.; Gerard, T. L.; Johns, E. M.; Lamkin, J. T.

2008-05-01

A multi-species spawning aggregation located on the banks south of St. Thomas includes several economically important fish species, including dog snapper, yellowfin grouper, Nassau grouper, and tiger grouper. Increased fishing pressure on these banks has prompted the Caribbean Fisheries Council to take actions such as seasonally closing fishing grounds and establishing Marine Protected Areas (MPAs). Due to a lack of biological and oceanographic data for the region, these management decisions have been based on professional judgment rather than scientific data. In response to this situation, NOAA scientists from SEFSC and AOML began an interdisciplinary field study in the region in 2007. Research cruises utilize biological sampling techniques such as MOCNESS, neuston, and bongo trawl tows simultaneously with standard physical sampling methods such as CTD/LADCP casts, hull- mounted water velocity measurements, and Lagrangian drifter deployments. The three year project aims to determine how the unprotected banks of the Virgin Islands and surrounding region, the seasonally closed banks and MPAs, and near-shore areas are ecologically linked in terms of larval dispersal, transport, and life history patterns. This collaboration should produce an assessment, based on scientific data, of the effectiveness of Caribbean Research Council management decisions and suggest modifications and improvements to current policy. Additionally, this project will also provide fisheries independent data, and develop ecological indices which can be integrated into stock assessment models. Analysis of data gathered during the project's first research cruise is yielding preliminary results. A total of 26,809 fish larvae were collected from the Grammanik and Red Hind Banks and surrounding regions. Of this total, 585 Serranidae (grouper) and 93 Lutjanidae (snapper) larval specimens were collected. Typical sampling transects included near-shore, shelf-break, and offshore regimes. The most

Shallow stratigraphy of the Skagit River Delta, Washington, derived from sediment cores

Science.gov (United States)

Grossman, Eric E.; George, Douglas A.; Lam, Angela

2011-01-01

Sedimentologic analyses of 21 sediment cores, ranging from 0.4 to 9.6 m in length, reveal that the shallow geologic framework of the Skagit River Delta, western Washington, United States, has changed significantly since 1850. The cores collected from elevations of 3.94 to -2.41 m (relative to mean lower low water) along four cross-shore transects between the emergent marsh and delta front show relatively similar environmental changes across an area spanning ~75 km2. Offshore of the present North Fork Skagit River and South Fork Skagit River mouths where river discharge is focused by diked channels through the delta, the entire 5–7-km-wide tidal flats are covered with 1–2 m of cross-bedded medium-to-coarse sands. The bottoms of cores, collected in these areas are composed of mud. A sharp transition from mud to a cross-bedded sand unit indicates that the tidal flats changed abruptly from a calm environment to an energetic one. This is in stark contrast to the Martha's Bay tidal flats north of the Skagit Bay jetty that was completed in the 1940s to protect the newly constructed Swinomish Channel from flooding and sedimentation. North of the jetty, mud ranging from 1 to 2 m thick drapes a previously silt- and sand-rich tidal flat. The silty sand is a sediment facies that would be expected there where North Fork Skagit River sedimentation occurred prior to jetty emplacement. This report describes the compositional and textural properties of the sediment cores by using geophysical, photographic, x-radiography, and standard sediment grain-size and carbon-analytical methods. The findings help to characterize benthic habitat structure and sediment transport processes and the environmental changes that have occurred across the nearshore of the Skagit River Delta. The findings will be useful for quantifying changes to nearshore marine resources, including impacts resulting from diking, river-delta channelization, shoreline development, and natural variations in fluvial

Modeling long period swell in Southern California: Practical boundary conditions from buoy observations and global wave model predictions

Science.gov (United States)

Crosby, S. C.; O'Reilly, W. C.; Guza, R. T.

2016-02-01

Accurate, unbiased, high-resolution (in space and time) nearshore wave predictions are needed to drive models of beach erosion, coastal flooding, and alongshore transport of sediment, biota and pollutants. On highly sheltered shorelines, wave predictions are sensitive to the directions of onshore propagating waves, and nearshore model prediction error is often dominated by uncertainty in offshore boundary conditions. Offshore islands and shoals, and coastline curvature, create complex sheltering patterns over the 250km span of southern California (SC) shoreline. Here, regional wave model skill in SC was compared for different offshore boundary conditions created using offshore buoy observations and global wave model hindcasts (National Oceanographic and Atmospheric Administration Wave Watch 3, WW3). Spectral ray-tracing methods were used to transform incident offshore swell (0.04-0.09Hz) energy at high directional resolution (1-deg). Model skill is assessed for predictions (wave height, direction, and alongshore radiation stress) at 16 nearshore buoy sites between 2000 and 2009. Model skill using buoy-derived boundary conditions is higher than with WW3-derived boundary conditions. Buoy-driven nearshore model results are similar with various assumptions about the true offshore directional distribution (maximum entropy, Bayesian direct, and 2nd derivative smoothness). Two methods combining offshore buoy observations with WW3 predictions in the offshore boundary condition did not improve nearshore skill above buoy-only methods. A case example at Oceanside harbor shows strong sensitivity of alongshore sediment transport predictions to different offshore boundary conditions. Despite this uncertainty in alongshore transport magnitude, alongshore gradients in transport (e.g. the location of model accretion and erosion zones) are determined by the local bathymetry, and are similar for all predictions.

Verifying mapping, monitoring and modeling of fine sediment pollution sources in West Maui, Hawai'i, USA

Science.gov (United States)

Cerovski-Darriau, C.; Stock, J. D.

2017-12-01

Coral reef ecosystems, and the fishing and tourism industries they support, depend on clean waters. Fine sediment pollution from nearshore watersheds threatens these enterprises in West Maui, Hawai'i. To effectively mitigate sediment pollution, we first have to know where the sediment is coming from, and how fast it erodes. In West Maui, we know that nearshore sediment plumes originate from erosion of fine sand- to silt-sized air fall deposits where they are exposed by grazing, agriculture, or other disturbances. We identified and located these sediment sources by mapping watershed geomorphological processes using field traverses, historic air photos, and modern orthophotos. We estimated bank lowering rates using erosion pins, and other surface erosion rates were extrapolated from data collected elsewhere on the Hawaiian Islands. These measurements and mapping led to a reconnaissance sediment budget which showed that annual loads are dominated by bank erosion of legacy terraces. Field observations during small storms confirm that nearshore sediment plumes are sourced from bank erosion of in-stream, legacy agricultural deposits. To further verify this sediment budget, we used geochemical fingerprinting to uniquely identify each potential source (e.g. stream banks, agricultural fields, roads, other human modified soils, and hillslopes) from the Wahikuli watershed (10 km2) and analyzed the fine fraction using ICP-MS for elemental geochemistry. We propose to apply this the fingerprinting results to nearshore suspended sediment samples taken during storms to identify the proportion of sediment coming from each source. By combining traditional geomorphic mapping, monitoring and geochemistry, we hope to provide a powerful tool to verify the primary source of sediment reaching the nearshore.

Nearshore Wave and Current Dynamics

Science.gov (United States)

1999-09-30

bottom perturbation and an " influence function ". This influence function has its maximum at the shoreline and decays away from the shore. Also, the...magnitude of the influence function increases with edge-wave mode. These results show that the dispersion relationship is more sensitive to the

Accumulation of methylmercury in rice and flooded soil in experiments with an enriched isotopic Hg(II) tracer

Science.gov (United States)

Strickman, R. J.; Mitchell, C. P. J.

2015-12-01

Methylmercury (MeHg) is a neurotoxin produced in anoxic aquatic sediments. Numerous factors, including the presence of aquatic plants, alter the biogeochemistry of sediments, affecting the rate at which microorganisms transform bioavailable inorganic Hg (IHg) to MeHg. Methylmercury produced in flooded paddy soils and its transfer into rice has become an important dietary consideration. An improved understanding of how MeHg reaches the grain and the extent to which rice alters MeHg production in rhizosphere sediments could help to inform rice cultivation practices. We conducted a controlled greenhouse experiment with thirty rice plants grown in individual, flooded pots amended with enriched 200Hg. Unvegetated controls were maintained under identical conditions. At three plant growth stages (vegetative growth, flowering, and grain maturity), ten plants were sacrificed and samples collected from soil, roots, straw, panicle, and grain of vegetated and unvegetated pots, and assessed for MeHg and THg concentrations. We observed consistent ratios between ambient and tracer MeHg between soils (0.36 ±0.04 — 0.44 ± 0.09) and plant compartments (0.23 ± 0.07 -0.34 ± 0.05) indicating that plant MeHg contamination originates in the soil rather than in planta methylation. The majority of this MeHg was absorbed between the tillering (4.48 ± 2.38 ng/plant) and flowering (8.43 ± 5.12 ng/pl) phases, with a subsequent decline at maturity (2.87 ± 1.23 ng/pl) only partly explained by translocation to the developing grain, indicating that MeHg was demethylated in planta. In contrast, IHg was absorbed from both soil and air, as evidenced by the higher ambient IHg concentrations compared to tracer (3.76 ± 1.19 vs. 0.27 ± 0.40 ng/g). Surprisingly, MeHg accumulation was significantly (p= 0.042-- 0.003) lower in vegetated vs. unvegetated sediments at flowering (1.41 ± 0.26 vs. 1.57 ± 0.23) and maturity (1.27 ± 0.22 vs. 1.71 ± 0.25), suggesting that plant exudates bound Hg

Mississippi Sound Remote Sensing Study

Science.gov (United States)

Atwell, B. H.

1973-01-01

The Mississippi Sound Remote Sensing Study was initiated as part of the research program of the NASA Earth Resources Laboratory. The objective of this study is development of remote sensing techniques to study near-shore marine waters. Included within this general objective are the following: (1) evaluate existing techniques and instruments used for remote measurement of parameters of interest within these waters; (2) develop methods for interpretation of state-of-the-art remote sensing data which are most meaningful to an understanding of processes taking place within near-shore waters; (3) define hardware development requirements and/or system specifications; (4) develop a system combining data from remote and surface measurements which will most efficiently assess conditions in near-shore waters; (5) conduct projects in coordination with appropriate operating agencies to demonstrate applicability of this research to environmental and economic problems.

Seagrass meadows as a globally significant carbonate reservoir

KAUST Repository

Mazarrasa, I.; Marbà , N.; Lovelock, C. E.; Serrano, O.; Lavery, P. S.; Fourqurean, J. W.; Kennedy, H.; Mateo, M. A.; Krause-Jensen, D.; Steven, A. D. L.; Duarte, Carlos M.

2015-01-01

There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha⁻¹, with an average of 654 ± 24 Mg PIC ha⁻¹, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of −8 ± 2 Mg PIC ha⁻¹ per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m⁻² yr⁻¹. Based on the global extent of seagrass meadows (177 000 to 600 000 km²), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr⁻¹, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO₂

Seagrass meadows as a globally significant carbonate reservoir

KAUST Repository

Mazarrasa, I.

2015-08-24

There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the particulate organic carbon (POC) stocks and accumulation rates and ignored the particulate inorganic carbon (PIC) fraction, despite important carbonate pools associated with calcifying organisms inhabiting the meadows, such as epiphytes and benthic invertebrates, and despite the relevance that carbonate precipitation and dissolution processes have in the global carbon cycle. This study offers the first assessment of the global PIC stocks in seagrass sediments using a synthesis of published and unpublished data on sediment carbonate concentration from 403 vegetated and 34 adjacent un-vegetated sites. PIC stocks in the top 1 m of sediment ranged between 3 and 1660 Mg PIC ha⁻¹, with an average of 654 ± 24 Mg PIC ha⁻¹, exceeding those of POC reported in previous studies by about a factor of 5. Sedimentary carbonate stocks varied across seagrass communities, with meadows dominated by Halodule, Thalassia or Cymodocea supporting the highest PIC stocks, and tended to decrease polewards at a rate of −8 ± 2 Mg PIC ha⁻¹ per degree of latitude (general linear model, GLM; p < 0.0003). Using PIC concentrations and estimates of sediment accretion in seagrass meadows, the mean PIC accumulation rate in seagrass sediments is found to be 126.3 ± 31.05 g PIC m⁻² yr⁻¹. Based on the global extent of seagrass meadows (177 000 to 600 000 km²), these ecosystems globally store between 11 and 39 Pg of PIC in the top metre of sediment and accumulate between 22 and 75 Tg PIC yr⁻¹, representing a significant contribution to the carbonate dynamics of coastal areas. Despite the fact that these high rates of carbonate accumulation imply CO₂

Changes in distributional patterns of plaice Pleuronectes platessa in the central and eastern North Sea; do declining nutrient loadings play a role?

DEFF Research Database (Denmark)

Støttrup, Josianne Gatt; Munk, Peter; Kodama, Masashi

2017-01-01

of offshore habitats as nursery areas by juvenile plaice in the North Sea appears not related to water depth per se but driven by specific processes dominating in near-shore areas and may be related to changes in nutrient loadings. This point to the importance of separating more general depth-related factors....... For the same time period available time series data on nutrient conditions in the coastalNorth Sea area showthat the freshwater nitrogen loading has decreased by about 50%. While nutrient concentrations in the ambient environment have been shown to influence growth in juvenile plaice through influence...... on their prey, we here inspect the potential linkage between distributional changes in plaice and the decline in nutrient loading.We compare plaice observations in coastal areas in the eastern North Sea,which have experienced large changes in eutrophication,with observations for the Dogger Bank, a large...

Effects of restoration management on the estuarine isopod Cyathura carinata: mediation by trematodes and habitat change

DEFF Research Database (Denmark)

Ferreira, S.M.; Brandao, A.; Baeta, A.

2007-01-01

A restoration programme was introduced in the Mondego Estuary (Portugal) to recover seagrass beds of Zostera noltii endangered by eutrophication. A long-term survey of 10 years was used to assess the development of the processes involved, focusing one of the key species (Cyathura carinata, Isopoda...... blooms, although both events caused dispersion of individuals. This isopod was not much influenced by the changes occurring in the estuary, showing an unalterable population structure during the entire study period. After 1998, its density and biomass became more stable at an inner unvegetated sand flat...

Application of State of the Art Modeling Techniques to Predict Flooding and Waves for a Coastal Area within a Protected Bay

Directory of Open Access Journals (Sweden)

Malcolm L. Spaulding

2017-03-01

Full Text Available Flood Insurance Rate Maps (FIRMs are developed by the Federal Emergency Management Agency (FEMA to provide guidance in establishing the risk to structures and infrastructure from storm surge sand associated waves in the coastal zone. The maps are used by state agencies and municipalities to help guide coastal planning and establish the minimum elevation and construction standards for new or substantially improved structures. A summary of the methods used and a comparison with the results of 2013 FIRM mapping are presented for Warwick, Rhode Island (RI, a coastal community located within Narragansett Bay. Because of its location, Warwick is protected from significant coastal erosion and wave attacks, but is subject to surge amplification. Concerns surrounding the FEMA methods used in the 2013 FIRM analysis are put in context with the National Research Council’s (NRC 2009 review of the FEMA coastal mapping program. New mapping is then performed using state of the art, fully coupled surge and wave modeling, and data analysis methods, to address the NRC concerns. The new maps and methodologies are in compliance with FEMA regulations and guidelines. This new approach makes extensive use of the numerical modeling results from the recent US Army Corp of Engineers, North Atlantic Coast Comprehensive Study (NACCS, 2015. Revised flooding maps are presented and compared to the 2013 FIRM maps, to provide insight into the differences. The new maps highlight the importance of developing better estimates of surge dynamics and the advancement in nearshore mapping of waves in flood inundated areas by the use of state of the art, two-dimensional, wave transformation models.

Infestation of oysters and mussels by mytilicolid copepods: differences between natural coastal habitats and two offshore cultivation sites in the German Bight

OpenAIRE

Pogoda, Bernadette; Jungblut, Simon; Buck, Bela H.; Hagen, Wilhelm

2012-01-01

The aim of this study was to determine the macro-parasitic infestation level of oysters from the southern German Bight focussing on copepods of the genus Mytilicola. Crassostrea gigas, Ostrea edulis and Mytilus edulis were collected at five locations: three nearshore sites in the eastern Wadden Sea and two offshore cultivation sites in the German Bight. To reveal seasonal variations one sampling site was investigated in winter and summer. At the nearshore sites, Mytilicola orientalis was regu...

Tracking particle-associated processes in nearshore environments by use of 234Th/238U disequilibrium

International Nuclear Information System (INIS)

Aller, R.C.; Benninger, L.K.; Cochran, J.K.

1980-01-01

Measurement of excess 234 Th (t 1 sub(/) 2 = 24.1 days) in surface sediment from 12 stations throughout Long Island Sound, U.S.A., demonstrates: (1) a mean (summer) sediment inventory of 3.6 dpm/cm 2 consistent with complete, nearly instantaneous removal of 234 Th from the overlying water and capture within the estuary, and (2) preferential association of excess 234 Th with small particles and inventory build-ups in muddy bottom areas. There may also be a tendency for higher inventories in areas of high physical or biogenic reworking of surface sediments. A range of particle reworking rates (0-5 cm) from -6 to 1.6 x 10 -6 cm 2 /s is found in the Sound with most values approx. 0.2-0.5 x 10 -6 cm 2 /s. The inventory and reworking patterns demonstrate the high mobility, both horizontal and vertical, of particles in the estuary on 234 Th decay time scales and are unequivocal evidence for control of reactive element distribution in the water column by the muddy regions of the basin. (orig.)

Metal surveys in South African estuaries I. Swartkops River

International Nuclear Information System (INIS)

Watling, R.J.; Watling, H.R.

1982-01-01

Water, surface sediment and sediment core samples were collected from sites in the Swartkops River up to 15 km from the mouth and analysed for up to sixteen elements. The results indicate the presence of four main areas of contamination in the river, at Redhouse, Swartkops, the brickworks and Amsterdam Hoek. The accumulation of zinc, copper, lead and nickel by oysters grown at the mouth of the river confirms the presence of greater than normal metal concentrations in the river. Fish-water Flats outfall contributes metals to the nearshore marine environment, but the strong tidal sweep disperses the effluent relatively quickly so that metal build-up in the area is minimal. In general, metal levels in the Swartkops River are low and, as yet, the area cannot be described as 'polluted' in the true sense of the word

Controls of multi-modal wave conditions in a complex coastal setting

Science.gov (United States)

Hegermiller, Christie; Rueda, Ana C.; Erikson, Li H.; Barnard, Patrick L.; Antolinez, J.A.A.; Mendez, Fernando J.

2017-01-01

Coastal hazards emerge from the combined effect of wave conditions and sea level anomalies associated with storms or low-frequency atmosphere-ocean oscillations. Rigorous characterization of wave climate is limited by the availability of spectral wave observations, the computational cost of dynamical simulations, and the ability to link wave-generating atmospheric patterns with coastal conditions. We present a hybrid statistical-dynamical approach to simulating nearshore wave climate in complex coastal settings, demonstrated in the Southern California Bight, where waves arriving from distant, disparate locations are refracted over complex bathymetry and shadowed by offshore islands. Contributions of wave families and large-scale atmospheric drivers to nearshore wave energy flux are analyzed. Results highlight the variability of influences controlling wave conditions along neighboring coastlines. The universal method demonstrated here can be applied to complex coastal settings worldwide, facilitating analysis of the effects of climate change on nearshore wave climate.

Follow that fish: Uncovering the hidden blue economy in coral reef fisheries.

Science.gov (United States)

Grafeld, Shanna; Oleson, Kirsten L L; Teneva, Lida; Kittinger, John N

2017-01-01

Despite their importance for human well-being, nearshore fisheries are often data poor, undervalued, and underappreciated in policy and development programs. We assess the value chain for nearshore Hawaiian coral reef fisheries, mapping post-catch distribution and disposition, and quantifying associated monetary, food security, and cultural values. We estimate that the total annual value of the nearshore fishery in Hawai'i is $10.3-$16.4 million, composed of non-commercial ($7.2-$12.9 million) and commercial ($2.97 million licensed + $148,500-$445,500 unlicensed) catch. Hawaii's nearshore fisheries provide >7 million meals annually, with most (>5 million) from the non-commercial sector. Over a third (36%) of meals were planktivores, 26% piscivores, 21% primary consumers, and 18% secondary consumers. Only 62% of licensed commercial catch is accounted for in purchase reports, leaving 38% of landings unreported in sales. Value chains are complex, with major buyers for the commercial fishery including grocery stores (66%), retailers (19%), wholesalers (14%), and restaurants (sharing. A small amount (~37,000kg) of reef fish-the equivalent of 1.8% of local catch-is imported annually into Hawai'i, 23,000kg of which arrives as passenger luggage on commercial flights from Micronesia. Evidence of exports to the US mainland exists, but is unquantifiable given existing data. Hawaiian nearshore fisheries support fundamental cultural values including subsistence, activity, traditional knowledge, and social cohesion. These small-scale coral reef fisheries provide large-scale benefits to the economy, food security, and cultural practices of Hawai'i, underscoring the need for sustainable management. This research highlights the value of information on the value chain for small-scale production systems, making the hidden economy of these fisheries visible and illuminating a range of conservation interventions applicable to Hawai'i and beyond.

Sedimentary architecture of the Holocene mud deposit off the southern Shandong Peninsula in the Yellow Sea

Science.gov (United States)

Qiu, Jiandong; Liu, Jian; Xu, Hong; Zhou, Liangyong

2018-01-01

Newly acquired high-resolution seismic profiles reveal a nearshore and an offshore mud depocenter offthe southern Shandong Peninsula in the Yellow Sea. The nearshore depocenter is distributed in bands along the south coast of Shandong Peninsula. The offshore depocenter is part of the distal subaqueous deltaic lobe, which deposited around the southeastern tip of the Shandong Peninsula. Between the two depocenters is a linear depression. The mud deposits directly overlie the postglacial transgressive surface and can be divided into lower and upper units by the Holocene maximum flooding surface. The nearshore and offshore units display different seismic structures. The lower unit of the nearshore deposit exhibits basal onlap, whereas the upper unit is characterized by progradation. The lower and upper units of the offshore deposit display distinct acoustic features. The lower unit has low-angle aggradation with internal reflectors generally dipping seaward and truncated by the Holocene maximum flooding surface, whereas the upper unit is characterized by aggradation and progradation landward rather than seaward. Results of geochemistry analysis of QDZ03 sediments and mineral analysis of WHZK01 sediments suggest that the nearshore deposit and the lower unit of the offshore deposit are derived from the proximal coastal sediments of the Shandong Peninsula and the Huanghe (Yellow) River sediments. The upper unit of the offshore deposit is mainly Huanghe River-derived. The lower unit of the mud deposit represents a post-glacial transgressive system tract according to dates of core QDZ03, and the upper unit represents a highstand system tract from middle Holocene to the present. These results will be of great significance to further understanding of the transportation of the Huanghe River sediments into the Yellow Sea and the spatial distribution of the subaqueous delta.

Evaluation of the Wave Energy Conversion Efficiency in Various Coastal Environments

Directory of Open Access Journals (Sweden)

Eugen Rusu

2014-06-01

Full Text Available The main objective of the present work was to assess and compare the wave power resources in various offshore and nearshore areas. From this perspective, three different groups of coastal environments were considered: the western Iberian nearshore, islands and an enclosed environment with sea waves, respectively. Some of the most representative existent wave converters were evaluated in the analysis and a second objective was to compare their performances at the considered locations, and in this way to determine which is better suited for potential commercial exploitation. In order to estimate the electric power production expected in a certain location, the bivariate distributions of the occurrences corresponding to the sea states, defined by the significant wave height and the energy period, were constructed in each coastal area. The wave data were provided by hindcast studies performed with numerical wave models or based on measurements. The transformation efficiency of the wave energy into electricity is evaluated via the load factor and also through the capture width, defined as the ratio between the electric power estimated to be produced by each specific wave energy converters (WEC and the expected wave power corresponding to the location considered. Finally, by evaluating these two different indicators, comparisons of the performances of three WEC types (Aqua Buoy, Pelamis and Wave Dragon in the three different groups of coastal environments considered have been also carried out. The work provides valuable information related to the effectiveness of various technologies for the wave energy extraction that would operate in different coastal environments.

Implications of Sea Level Rise on Coastal Flood Hazards

Science.gov (United States)

Roeber, V.; Li, N.; Cheung, K.; Lane, P.; Evans, R. L.; Donnelly, J. P.; Ashton, A. D.

2012-12-01

Recent global and local projections suggest the sea level will be on the order of 1 m or higher than the current level by the end of the century. Coastal communities and ecosystems in low-lying areas are vulnerable to impacts resulting from hurricane or large swell events in combination with sea-level rise. This study presents the implementation and results of an integrated numerical modeling package to delineate coastal inundation due to storm landfalls at future sea levels. The modeling package utilizes a suite of numerical models to capture both large-scale phenomena in the open ocean and small-scale processes in coastal areas. It contains four components to simulate (1) meteorological conditions, (2) astronomical tides and surge, (3) wave generation, propagation, and nearshore transformation, and (4) surf-zone processes and inundation onto dry land associated with a storm event. Important aspects of this package are the two-way coupling of a spectral wave model and a storm surge model as well as a detailed representation of surf and swash zone dynamics by a higher-order Boussinesq-type wave model. The package was validated with field data from Hurricane Ivan of 2005 on the US Gulf coast and applied to tropical and extratropical storm scenarios respectively at Eglin, Florida and Camp Lejeune, North Carolina. The results show a nonlinear increase of storm surge level and nearshore wave energy with a rising sea level. The exacerbated flood hazard can have major consequences for coastal communities with respect to erosion and damage to infrastructure.

High air-sea CO 2 uptake rates in nearshore and shelf areas of Southern Greenland: Temporal and spatial variability

DEFF Research Database (Denmark)

Rysgaard, Søren; Mortensen, J.; Juul-Pedersen, T.

2012-01-01

significant correlation between average annual gross primary production and annual air-sea flux during 2005-2010, which suggests that regulation of pCO 2 in the fjord is more complex. Despite three confined periods with supersaturated pCO 2 conditions in surface waters during 2005-2010, Godthåbsfjord can......The present study is based on hourly samplings of wind speed, monthly sampling sessions of temperature, salinity, dissolved inorganic carbon, alkalinity, nutrients, primary productivity and vertical export in the outer sill region (station GF3) of a sub-arctic SW Greenland fjord (Godthåbsfjord......) through 2005-2010. Air-sea CO 2 fluxes varied at GF3 from c. -20gCm -2month -1 (uptake from the atmosphere) to 25gCm -2month -1 (release to the atmosphere) during 2005-10. The average annual air-sea CO 2 flux of -83 to -108gCm -2yr -1 was within the range of the local gross annual primary productivity...

Impact of pond aquaculture effluents on seagrass performance in NE Hainan, tropical China

International Nuclear Information System (INIS)

Herbeck, Lucia S.; Sollich, Miriam; Unger, Daniela; Holmer, Marianne; Jennerjahn, Tim C.

2014-01-01

Highlights: • Seagrass performance in relation to large-scale pond aquaculture was assessed. • Effluent-affected seagrass meadows have a low biodiversity, shoot density and biomass. • Shading by epiphytes and sulphide poisoning are major decline mechanisms of seagrasses. • Distance to effluent source and pond agglomeration size are major determinants of seagrass degradation. - Abstract: The impact of pond aquaculture effluents on the distribution and performance of seagrasses was examined in NE Hainan, tropical China. Samples were taken along transects in three back-reef areas with different extent of aquaculture production in their hinterland. High δ 15 N in seagrass leaves and epiphytes (6–9‰) similar to values in pond effluents documented aquaculture as dominant nitrogen source in the back-reefs with decreasing impact with distance from shore. Seagrass species abundance, shoot density and biomass were lower and concentrations of nutrients, chlorophyll and suspended matter were higher at nearshore sites with high and moderate pond abundance than at the control site. High epiphyte loads and low δ 34 S in seagrass leaves suggest temporal shading and sulphide poisoning of the nearshore seagrasses. Observed gradients in environmental parameters and seagrass performance indicate that the distance from the pond outlets and size of the adjacent pond agglomeration are major determinants of seagrass degradation

Investigation of the stochastic nature of wave processes for renewable resources management: a pilot application in a remote island in the Aegean sea

Science.gov (United States)

Moschos, Evangelos; Manou, Georgia; Georganta, Xristina; Dimitriadis, Panayiotis; Iliopoulou, Theano; Tyralis, Hristos; Koutsoyiannis, Demetris; Tsoukala, Vicky

2017-04-01

The large energy potential of ocean dynamics is not yet being efficiently harvested mostly due to several technological and financial drawbacks. Nevertheless, modern renewable energy systems include wave and tidal energy in cases of nearshore locations. Although the variability of tidal waves can be adequately predictable, wind-generated waves entail a much larger uncertainty due to their dependence to the wind process. Recent research has shown, through estimation of the wave energy potential in coastal areas of the Aegean Sea, that installation of wave energy converters in nearshore locations could be an applicable scenario, assisting the electrical network of Greek islands. In this context, we analyze numerous of observations and we investigate the long-term behaviour of wave height and wave period processes. Additionally, we examine the case of a remote island in the Aegean sea, by estimating the local wave climate through past analysis data and numerical methods, and subsequently applying a parsimonious stochastic model to a theoretical scenario of wave energy production. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

Climate change impacts on rural poverty in low-elevation coastal zones

Science.gov (United States)

Barbier, Edward B.

2015-11-01

This paper identifies the low-elevation coastal zone (LECZ) populations and developing regions most vulnerable to sea-level rise and other coastal hazards, such as storm surges, coastal erosion and salt-water intrusion. The focus is on the rural poor in the LECZ, as their economic livelihoods are especially endangered both directly by coastal hazards and indirectly through the impacts of climate change on key coastal and near-shore ecosystems. Using geo-spatially referenced malnutrition and infant mortality data for 2000 as a proxy for poverty, this study finds that just 15 developing countries contain over 90% of the world's LECZ rural poor. Low-income countries as a group have the highest incidence of poverty, which declines somewhat for lower middle-income countries, and then is much lower for upper middle-income economies. South Asia, East Asia and the Pacific and Sub-Saharan Africa account for most of the world's LECZ rural poor, and have a high incidence of poverty among their rural LECZ populations. Although fostering growth, especially in coastal areas, may reduce rural poverty in the LECZ, additional policy actions will be required to protect vulnerable communities from disasters, to conserve and restore key coastal and near-shore ecosystems, and to promote key infrastructure investments and coastal community response capability.

Water masses and mesoscale control on latitudinal and cross-shelf variations in larval fish assemblages off NW Africa

Science.gov (United States)

Olivar, M. Pilar; Sabatés, Ana; Pastor, Maria V.; Pelegrí, Josep L.

2016-11-01

We explore the associations between larval fish assemblages and oceanographic conditions in the upper ocean (top 200 m) along the African slope, from tropical (15°N) to subtropical (35°N) latitudes, during a period of intense upwelling. In this extensive region, the northward Mauritanian Current and Poleward Undercurrent carry South Atlantic Central Waters (SACW) while the southward Canary Upwelling Current transports North Atlantic Central Waters (NACW). South of Cape Blanc we only find SACW, and north of Cape Blanc there is NACW far offshore and a combination of NACW and SACW nearshore, separated by the Canary Upwelling Front (CUF). The larvae of different myctophid species serve as indicators of the water masses, e.g. S. veranyi and M. punctatum were found in some coastal stations that were dominated by NACW, while the tropical mesopelagic B. argyrogaster, H. macrochir, M. affine and S. kreffti were associated to the SACW. The along-slope offshore convergence of NACW and SACW takes place at the Cape Verde Frontal Zone (CVFZ), representing a region of extensive offshore export for larvae of coastal species, S. pilchardus and E. encrasicolus, far from their nearshore spawning area. The large-scale frontal systems (CVFZ and CUF) and mesoscale eddies contribute to retain larvae within productive waters, influencing both coastal and oceanic species.

Movements of blue rockfish (Sebastes mystinus off central California with comparisons to similar species.

Directory of Open Access Journals (Sweden)

Kristen M Green

Full Text Available Olive (Sebastes serranoides, black (Sebastes melanops, and blue rockfish (Sebastes mystinus are all common inhabitants of nearshore ecosystems on the West coast of North America and important components of the recreational fishery off California. Acoustic monitoring studies indicate that olive rockfish are highly residential and that black rockfish are capable of long migrations and have less site fidelity; yet little is known about the long-term movements of blue rockfish. External tag-recapture studies indicate that blue rockfish may have intermediate movements relative to these congener nearshore species. To better understand the site fidelity, and daily and seasonal movements of blue rockfish over long (>1-year time scales, we placed acoustic transmitters into 21 adult blue rockfish (30-41 cm total length in Carmel Bay, California. Blue rockfish displayed intermediate movement patterns and residency relative to other similar kelp forest rockfish species. Two-thirds of tagged blue rockfish (13 fish exhibited high residency to the study area (>12 mo. When in residence, mean home range of blue rockfish was 0.23 km2, however as many as 30% of tagged blue rockfish shifted their core home range area during the study. Most shifts in home range occurred during upwelling season, and tagged fish moved up to 3.1 km when in residence. Blue rockfish with short residence times were last detected in the study area in late winter and early spring. Blue rockfish were observed at shallower depths during day than night, likely indicative of diurnal feeding. However, over longer time scales, blue rockfish were detected at deeper depths during upwelling periods and with increased wave heights. Daily and seasonal vertical movements of blue rockfish may be influenced by upwelling conditions and local prey abundance.

Accumulation of nitrogen and organic matter during primary succession of Leymus arenarius dunes on the volcanic island Surtsey, Iceland

Science.gov (United States)

Stefansdottir, G.; Aradottir, A. L.; Sigurdsson, B. D.

2014-05-01

The volcanic island of Surtsey has been a natural laboratory where the primary succession of flora and fauna has been monitored, since it emerged from the N-Atlantic Ocean in 1963. We quantified the accumulation rates of nitrogen (N) and soil organic matter (SOM) in a 37 year long chronosequence of Leymus arenarius dunes in order to illuminate the spatiotemporal patterns in their build-up in primary succession. The Leymus dune area, volume and height grew exponentially over time. Aboveground plant biomass, cover or number of shoots per unit area did not change significantly with time, but root biomass accumulated with time, giving a root-shoot ratio of 19. The dunes accumulated on average 6.6 kg N ha-1 year-1, which was 3.5 times more than is received annually by atmospheric deposition. The extensive root system of Leymus seems to effectively retain and accumulate large part of the annual N deposition, not only deposition directly on the dunes but also from the adjacent unvegetated areas. SOM per unit area increased exponentially with dune age, but the accumulation of roots, aboveground biomass and SOM was more strongly linked to soil N than time: 1 g m-2 increase in soil N led on the average to 6 kg C m-2 increase in biomass and SOM. The Leymus dunes, where most of the N has been accumulated, will therefore probably act as hot-spots for further primary succession of flora and fauna on the tephra sands of Surtsey.

Assessment of the Species Composition, Densities, and Distribution of Native Freshwater Mussels along the Benton County Shoreline of the Hanford Reach, Columbia River, 2004

Energy Technology Data Exchange (ETDEWEB)

Mueller, Robert P.; Tiller, Brett L.; Bleich, Matthew D.; Turner, Gerald; Welch, Ian D.

2011-01-31

The Hanford Reach of the Columbia River is the last unimpounded section of the river and contains substrate characteristics (cobble, gravel, sand/silt) suitable for many of the native freshwater mussels known to exist in the Pacific Northwest. Information concerning the native mussel species composition, densities, and distributions in the mainstem of the Columbia River is limited. Under funding from the U.S. Department of Energy Richland Operations Office (DOE-RL), Pacific Northwest National Laboratory conducted an assessment of the near-shore habitat on the Hanford Reach. Surveys conducted in 2004 as part of the Ecological Monitoring and Compliance project documented several species of native mussels inhabiting the near-shore habitat of the Hanford Reach. Findings reported here may be useful to resource biologists, ecologists, and DOE-RL to determine possible negative impacts to native mussels from ongoing near-shore remediation activities associated with Hanford Site cleanup. The objective of this study was to provide an initial assessment of the species composition, densities, and distribution of the freshwater mussels (Margaritiferidae and Unionidae families) that exist in the Hanford Reach. Researchers observed and measured 201 live native mussel specimens. Mussel density estimated from these surveys is summarized in this report with respect to near-shore habitat characteristics including substrate size, substrate embeddedness, relative abundance of aquatic vegetation, and large-scale geomorphic/hydrologic characteristics of the Hanford Reach.

Variability in the distribution of planktonic fish eggs and larvae in the nearshore waters off Bombay

Digital Repository Service at National Institute of Oceanography (India)

Gajbhiye, S.N.; Nair, V.R.; Desai, B.N.

represented different environmental conditions. Fish eggs and larvae were common in the area of study with maximum abundance in December 1979 and April/ August 1980. Mean density of fish eggs was maximum along the Mahim transect while population of larvae...

Radioactive waste in the marine environment

International Nuclear Information System (INIS)

Lowman, F.G.

1975-01-01

The introduction of radionuclides into near-shore marine areas is considered in relation to Federal Regulations and to the hazards posed to man and to marine organisms living near the site of introduction of the contaminants. The use of the critical pathway concept, for evaluating hazards to man from radionuclides in his food, is discussed and the specific activity concept is applied to demonstrate the degree of hazard to man which could result from normal reactor operation using sea water for the coolant. The relative hazards to marine organisms from naturally occurring and reactor-produced radionuclides are also evaluated. (U.S.)