Science.gov

Sample records for bights

  1. Tidal wave transformations in the German Bight

    NASA Astrophysics Data System (ADS)

    Stanev, Emil V.; Al-Nadhairi, Rahma; Staneva, Joanna; Schulz-Stellenfleth, Johannes; Valle-Levinson, Arnoldo

    2014-07-01

    Mesoscale and submesoscale dynamics associated with tidal wave transformations were addressed in the German Bight using numerical simulations. Tidal gauge and velocity observations in several locations were used to validate the numerical model. A downscaling approach included analysis of simulations with horizontal resolutions of 1, 0.4, and 0.2 km. It was shown that the modified tidal wave lost most of its energy after reflection or refraction over the eastern part of the German Bight. Energy loss resulted in a pronounced change of the wave's spectral composition and generation of overtides. Tidal oscillations were modified by mesoscale processes associated with bathymetric channels. Semidiurnal and quarterdiurnal tides revealed very different spatial patterns. The former were aligned with the bathymetric channels, while the latter were rather "patchy" and had about half the spatial scales. In numerous areas around the bathymetric channels, the major axis of the M4 ellipses was normal or at some angle with the major axis of the M2 ellipses. Thus, higher harmonics developed "orthogonal" patterns that drove secondary circulations. Moreover, the ratio between spring and neap tidal amplitudes was relatively low in the Wadden Sea, showing reduced sensitivity of this very shallow area to fortnightly tidal variations. It was demonstrated that simulated hydrodynamics patterns help explain the physical mechanism shaping the median grain size distribution in the German Bight.

  2. Modelling cyclonic eddies in the Delagoa Bight region

    NASA Astrophysics Data System (ADS)

    Cossa, O.; Pous, S.; Penven, P.; Capet, X.; Reason, C. J. C.

    2016-05-01

    The objective of this study is to document and shed light on the circulation around the Delagoa Bight region in the southern Mozambique Channel using a realistic modelling approach. A simulation including mesoscale forcings at the boundaries of our regional configuration succeeds in reproducing the general circulation in the region as well as the existence of a semi-permanent cyclonic eddy, whose existence is attested by in situ measurements in the Bight. Characterised by a persistent local minimum in SSH located around 26°S-34°E, this cyclonic eddy termed herein the Delagoa Bight lee eddy occurs about 25% of the time with no clear seasonal preference. Poleward moving cyclones, mostly generated further north, occur another 25% of the time in the Bight area. A tracking method applied to eddies generated in Delagoa Bight using model outputs as well as AVISO data confirms the model realism and provides additional statistics. The diameter of the eddy core varies between 61 and 147 km and the average life time exceeds 20 days. Additional model analyses reveal the systematic presence of negative vorticity in the Bight that can organise and form a Delagoa Bight lee eddy depending on the intensity of an intermittent southward flow along the shore and the spatial distribution of surrounding mesoscale features. In addition, the model solution shows other cyclonic eddies generated near Inhambane and eventually travelling through the Bight. Their generation and pathways appears to be linked with large Mozambique Channel rings.

  3. New York Bight restoration plan. Comprehensive plan for addressing floatable debris in the New York Bight

    SciTech Connect

    Not Available

    1991-07-01

    The sources of floatable debris in the New York Bight and the problems caused by the debris are fairly well understood. Because the impacts of floatable debris were particularly severe in the New York/New Jersey region during 1987 and 1988, a short-term action plan that focused on cleanup measures was developed and implemented during the summer of 1989. However, longer-term actions, aimed at reducing the amount of debris in New York/New Jersey waters, are clearly needed. The plan developed by an interagency workgroup, describes such actions and makes specific recommendations for implementing them. The longer-term actions, including (1) preventive actions, (2) education programs, and (3) regulatory actions, all of which will reduce introduction of plastic and other floatable debris to the New York Bight.

  4. Antarctic intermediate water intrusion into South Atlantic Bight shelf waters

    NASA Astrophysics Data System (ADS)

    Kashgarian, Michaele; Tanaka, Noriyuki

    1991-02-01

    Surface seawater samples were collected from seven stations on the coastline bordering the South Atlantic Bight and the southern Mid-Atlantic Bight in March 1986 and analysed for radiocarbon. Depletion in radiocarbon activity was observed in shelf water along the South Carolina coast at Myrtle Beach and Isle of Palms. If Sargasso Sea surface water withΔ 14C = 168‰ and Antarctic Intermediate Water (AAIW) withΔ 14C = -90‰ are two end members which supply water to this coastal region, a contribution of about 20-25% AAIW is required to produce theΔ 14C values observed.

  5. GEOS-3 radar altimeter study for the South Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Leitao, C. D.; Huang, N.; Parsons, C. L.; Parra, C. G.; Mcmill, J. D.; Hayes, G. S.

    1980-01-01

    Three years of radar altimeter data from GEOS-3 for the South Atlantic Bight were processed. Mean monthly topographic maps were produced which estimate geostrophic flow in the region. Statistical distribution of the surface wind speed and significant wave height as a function of both space and time are presented.

  6. Detection of ocean waste in the New York Bight

    NASA Technical Reports Server (NTRS)

    Philpot, W.; Klemas, V.

    1979-01-01

    The application of remote sensing to detection and monitoring of ocean waste disposal in the New York Bight is discussed. Attention is focused on the two major pollutants in this area--sewage sludge and iron-acid waste--and on detecting and identifying these pollutants. The emphasis is on the use of LANDSAT multispectral data in identifying these pollutants and distinguishing them from other substances. The analysis technique applied to the LANDSAT data is the eigenvector. This approach proved to be quite successful in detecting iron-acid waste of the coast of Delaware and is applied here with relatively minor modifications. The results of the New York Bight work are compared to the Delaware results. Finally, other remote sensing systems (Nimbus G, aircraft photography and multispectral scanner systems) are discussed as possible complements of or replacements for the Landsat observations.

  7. Wrecks as artificial lobster habitats in the German Bight

    NASA Astrophysics Data System (ADS)

    Krone, Roland; Schröder, Alexander

    2011-03-01

    Once, the European lobster could be found in high abundances on rocky substrate around the island of Helgoland. Since the 1960s, the stock has been decreasing dramatically. Until now, it has been assumed that the lobster stock of Helgoland is the only one in the German Bight. Here, we provide first information about lobster distribution inside the German Bight off Helgoland. Diving in situ observations revealed that lobsters inhabit at least 15.6% of all 64 investigated wrecks. Considering the difficulties of detecting lobsters at wrecks, the true percentage is most likely much higher. Their locations are spatially homogenously distributed throughout the inspected area. The study indicates a broad distribution of the European lobster over the German Bight. The habitats provided by a considerable fraction of the more than one thousand wrecks outside the Wadden Sea are potential lobster refuges within the mud and sand dominated sea floor. Besides providing additional habitats, they represent stepping stones enhancing the connectivity of the North Sea lobster population.

  8. Coastal ocean transport patterns in the central Southern California Bight

    USGS Publications Warehouse

    Noble, M.A.; Rosenberger, K.J.; Hamilton, P.; Xu, J. P.

    2009-01-01

    In the past decade, several large programs that monitor currents and transport patterns for periods from a few months to a few years were conducted by a consortium of university, federal, state, and municipal agencies in the central Southern California Bight, a heavily urbanized section of the coastal ocean off the west coast of the United States encompassing Santa Monica Bay, San Pedro Bay, and the Palos Verdes shelf. These programs were designed in part to determine how alongshelf and cross-shelf currents move sediments, pollutants, and suspended material through the region. Analysis of the data sets showed that the current patterns in this portion of the Bight have distinct changes in frequency and amplitude with location, in part because the topography of the shelf and upper slope varies rapidly over small spatial scales. However, because the mean, subtidal, and tidal-current patterns in any particular location were reasonably stable with time, one could determine a regional pattern for these current fields in the central Southern California Bight even though measurements at the various locations were obtained at different times. In particular, because the mean near-surface flows over the San Pedro and Palos Verdes shelves are divergent, near-surface waters from the upper slope tend to carry suspended material onto the shelf in the northwestern portion of San Pedro Bay. Water and suspended material are also carried off the shelf by the mean and subtidal flow fields in places where the orientation of the shelf break changes abruptly. The barotropic tidal currents in the central Southern California Bight flow primarily alongshore, but they have pronounced amplitude variations over relatively small changes in alongshelf location that are not totally predicted by numerical tidal models. Nonlinear internal tides and internal bores at tidal frequencies are oriented more across the shelf. They do not have a uniform transport direction, since they move fine sediment

  9. Southern California Bight 2003 Regional Monitoring Program: V. water quality

    USGS Publications Warehouse

    Nezlin, Nikolay P.; DiGiacomo, Paul M.; Weisberg, Stephen B.; Diehl, Dario W.; Warrick, Jonathan A.; Mengel, Michael J.; Jones, Burton H.; Reifel, Kristen M.; Johnson, Scott C.; Ohlmann, J. Carter; Washburn, Libe; Terrill, Eric J.

    2007-01-01

    More than $30 million is expended annually on environmental monitoring in the Southern California Bight (SCB), yet only 5% of the Bight is monitored on an ongoing basis. Therefore, environmental managers in the SCB decided to expand their monitoring program and, starting in 1994, decided to conduct periodic regional assessments of ecosystem condition and assess the overall health of the SCB. Sixty-five different organizations collaborated in 2003 to create the third SCB Regional Monitoring Program (Bight '03). Bight '03 was designed to be integrated regional monitoring program that encompasses regulatory, academic, and non-governmental agencies. Bight '03 had three components: Coastal Ecology, Shoreline Microbiology, and Water Quality. This report addresses the purpose, approach, findings, and recommendations from the Water Quality component, which focused on contamination-laden stormwater runoff, in particularly its variability in time and space as well as its short-term ecological impacts. Specifically, the Bight '03 Water Quality component had three primary goals, the first of which was to described the temporal evolution of stormwater plumes produced by the major southern California rivers. Specifically, the study was intended to determine how far offshore the plumes extended, how rapidly they advected, how long before the plumes dispersed and how these properties differed among storms and river systems. The second goal was to describe how the physical properties (e.g., turbidity, temperature, salinity) of the plume related to biogeochemical and ecological properties that are of more direct concern to the water quality management community. Accomplished primarily through ship-based sampling of water quality parameters, this second goal was to describe how far offshore, and for how ;long after the storm, elevated bacterial concentrations, toxicity, and nutrients could be detected. Similar to the fist goal, the study also addressed how these answers differed

  10. Sewage contamination in the new york bight. Coprostanol as an indicator

    USGS Publications Warehouse

    Hatcher, P.G.; McGillivary, P.A.

    1979-01-01

    Sediments of the New York Bight are analyzed for coprostanol, a fecal steroid, to determine the degree of sewage contamination. Coprostanol, when reported as a percentage of total steroids (% coprostanol), can be quantitatively related to the amount of sewage-derived organic matter. Furthermore, coprostanol is quite persistent in anoxic silts of the Bight and, thus, can be used to delineate historical contamination in these silts. Based on the sediments analyzed, the New York Bight is shown to be highly contaminated with sewage (most likely ocean-dumped sewage sludge), especially in the topographically low areas near the dump site, where black silts have been known to accumulate.

  11. Changes in source waters to the Southern California Bight

    NASA Astrophysics Data System (ADS)

    Bograd, Steven J.; Buil, Mercedes Pozo; Lorenzo, Emanuele Di; Castro, Carmen G.; Schroeder, Isaac D.; Goericke, Ralf; Anderson, Clarissa R.; Benitez-Nelson, Claudia; Whitney, Frank A.

    2015-02-01

    Historical hydrographic data (1984-2012) from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program and global reanalysis products were used to quantify recent water mass variability off the coast of Southern California. Dissolved oxygen concentrations continued to decline within the lower pycnocline, concurrent with strong increases in nitrate and phosphate that have spatial patterns matching those of dissolved oxygen. Silicic acid also shows an increasing trend in the offshore portion of the region, but has strong and opposing trends in the upper (increasing) and lower-pycnocline (decreasing) within the Southern California Bight. The varying rates of change in the inorganic nutrients yield a more complex pattern of variability in the nutrient ratios, resulting in large decreases in the N:P and Si:N ratios within the Southern California Bight at depths that provide source waters for upwelling. Basin-scale reanalysis products are consistent with low-frequency water mass changes observed off Southern California and suggest that advection of modified source waters is the cause of the variability. The biogeochemical changes described here may have important impacts on the regional ecosystem, including a reduction of viable pelagic habitat and community reorganization.

  12. Ecological stress and the New York Bight: science and management

    SciTech Connect

    Mayer, G.F.

    1982-01-01

    An often-voiced criticism of the environmental regulatory process is the failure to maintain adequate lines of communication among legislators and managers charged with developing and implementing environmental policy and scientists engaged in environmental research. The former two groups have a need for definitive information and unequivocal pronouncements on the environmental effects or ecological implications of specific actions. Members of the latter group, on the other hand, often are unable to respond precisely. They are trained to report on observations, to avoid speculation, and to enumerate the strengths and weaknesses of conclusions. Such opposing approaches have estranged these groups and have limited their interactions. The organization of the volume reflects that of the symposium. In all, nine panels were convened: five on science and four on management. Three science panels reviewed organismic effects of pollutants on fishes, bottom-dwelling organisms, and plankton/neuston (i.e., effects on cells, tissues, and individual plants and animals). The remaining two science panels explored implications of toxicant additions and nutrient and carbon loadings to communities and ecosystems of the New York Bight. Reports of the science panels are presented in the first section of the volume. By adopting a two-part format, the Editorial Board sought to produce a volume on the New York Bight of use to a range of readers from technical specialists to governmental leaders, decision-makers, members of the public, and students who may lack extensive technical backgrounds.

  13. Variability of surface pigment concentrations in the South Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Mcclain, Charles R.; Yoder, James A.; Blanton, J. O.; Atkinson, L. P.; Lee, T. N.

    1988-01-01

    A time sequence of surface pigment images of the South Atlantic Bight (SAB), derived from the Nimbus 7 CZCS for the period between November 1978 and October 1979, was correlated with in situ observations of hydrographic parameters, fresh-water discharge, sea level, coastal winds, and currents in order to couple physical processes and the spatial and temporal variability of the surface pigment fields. A definite seasonal modulation of the surface pigment fields was found, with the concentrations in the Georgia Bight being highest in summer, and those north of Cape Romain highest in winter. This phase difference was found to be the result of variations in wind fields, Gulf Stream-shelf interactions, and fresh-water discharge patterns. At some locations (e.g., near Charleston) the alongshore band of high pigment concentrations increased in width throughout the year; at other locations (near Jacksonville), the alongsore band exhibited a minimum width in the summer and a maximum width in the fall of 1979.

  14. Biological processes in the water column of the South Atlantic bight

    SciTech Connect

    Paffenhoefer, G.A.; Yoder, J.A.

    1980-01-31

    Progress is reported on research conducted during 1979 on the biological oceanography of the South Atlantic Bight. The presentation consists of a number of published articles and abstracts of oral presentations. (ACR)

  15. Sources and Fates of Dissolved Organic Matter in the Mid-Atlantic Bight

    SciTech Connect

    Hopkinson, C. S.

    2000-08-16

    The objectives of the research program were to identify and determine the relative importance of various sources of dissolved organic matter to the continental shelf, and to estimate the net carbon balance for the Middle Atlantic Bight.

  16. 3D Propagation and Geoacoustic Inversion Studies in the Mid-Atlantic Bight

    DTIC Science & Technology

    2016-06-07

    3D Propagation and Geoacoustic Inversion Studies in the Mid-Atlantic Bight Kevin B. Smith Code PH/Sk, Department of Physics Naval Postgraduate...properties and measured transmission loss. Results from this analysis will be considered in the context of geoacoustic inversions . OBJECTIVES To...bathymetric features and ocean fronts near the shelf break of the mid-Atlantic Bight, and use of various data for geoacoutic inversion studies. The results

  17. The Geyser Bight geothermal area, Umnak Island, Alaska

    SciTech Connect

    Motyka, R.J. ); Nye, C.J. Univ. of Alaska, Fairbanks, AK . Geophysical Inst.); Turner, D.L. . Geophysical Inst.); Liss, S.A. )

    1993-08-01

    The Geyser Bight geothermal area contains one of the hottest and most extensive areas of thermal springs in Alaska, and is the only site in the state with geysers. Heat for the geothermal system is derived from crustal magma associated with Mt. Recheshnoi volcano. Successive injections of magma have probably heated the crust to near its minimum melting point and produced the only high-SiO[sub 2] rhyolites in the oceanic part of the Aleutian arc. At least two hydrothermal reservoirs are postulated to underlie the geothermal area and have temperatures of 165 and 200 C, respectively, as estimated by geothermometry. Sulfate-water isotope geothermometers suggest a deeper reservoir with a temperature of 265 C. The thermal spring waters have relatively low concentrations of Cl (600 ppm) but are rich in B (60 ppm) and As (6 ppm). The As/Cl ratio is among the highest reported for geothermal waters. 41 refs., 12 figs., 8 tabs.

  18. Middle Atlantic Bight Marine Ecosystem: A Regional Forecast Model Study

    NASA Astrophysics Data System (ADS)

    Kim, H.; Coles, V. J.; Garraffo, Z. D.

    2011-12-01

    Changes in basin scale climate patterns can drive changes in mesoscale physical oceanographic processes and subsequent alterations of ecosystem states. Climatic variability can be induced in the northeastern shelfbreak large marine ecosystem by climate oscillations, such as North Atlantic Oscillation, Atlantic Multidecadal Oscillation; and long-term trends, such as a warming pattern. Short term variability can be induced by changes in the water masses in the northern and southern boundaries, by Gulf Stream path and transport variations, and by local mesoscale and submesoscale features. A coupled bio-physical model (HYbrid Coordinate Ocean Model) is being used to forecast the evolution of the frontal and current systems of the shelf and Gulf Stream, and subsequent changes in thermal conditions and ecosystem structure over the Middle Atlantic Bight (MAB). This study aims to forecast the ocean state and nutrients in the MAB, and to investigate how cross-shelf exchanges of different water masses could affect nutrient budgets, primary and secondary production, and fish populations in coastal and shelf marine ecosystems. Preliminary results are shown for a regional MAB model nested to the global 1/12o HYCOM run at NOAA/NCEP/EMC using Naval Oceanographic Office (NAVO) daily initialization. Elements of this simulation are nutrient influx condition at the northern and southern boundaries through regression to ocean thermodynamic variables, and nutrient input at the river mouths.

  19. Circulation on the continental shelf within the Mississippi Bight

    NASA Astrophysics Data System (ADS)

    Howden, Stephan D.; Kern, Amy

    2013-06-01

    The University of Southern Mississippi's Central Gulf of Mexico Ocean Observing System (CenGOOS) operates three long-range (~200 km) 5 MHz CODAR high frequency radar (HFR) stations at Singing River Island in Pascagoula, Mississippi, Gulf State Park in Orange Beach, Alabama, and Henderson Beach State Park in Destin, Florida. Each station broadcasts electromagnetic (EM) waves that follow the conducting sea surface and are Bragg-scattered preferentially by surface gravity waves with a wavelength of one half the wavelength of the EM waves moving towards or away from the antenna. The back-scattered waves are Doppler shifted by the sum of the speed of the waves through the water and the component of the surface velocity in the radial direction to the receive antenna. If the water depth is sufficient for the deep-water approximation to hold (in this case deeper than 20 m), the wave speed is a function of only the wavelength, so it is known from the Bragg-scattering condition. Thus, the component of the surface velocity radial to the receive antenna can be computed from the amount of Doppler shift, and these components are known as "radials". Where there is overlapping coverage of radials, the total surface current vectors are estimated. The HFR stations cover much of the Mississippi Bight (MSB) seaward of the 20 m isobath. The surface current fields have been analyzed for annual and seasonal climatology.

  20. Nearshore surface currents in the Chesapeake Bight during summer

    NASA Astrophysics Data System (ADS)

    Johnson, Donald R.

    1987-04-01

    In this study, several different approaches are used to study coastal surface currents in an application to the dispersion of blue crab larvae from Chesapeake Bay onto the Middle Atlantic Bight. Observations from the deployment of a newly developed surface current meter (RBCM—Rapid Boundary Current Meter) are presented and compared to calculated surface currents from a simple model. In addition, using currents calculated with actual winds in this model, traces are constructed from point of encounter of larvae on the shelf back to the bay entrance. This has provided a unique Lagrangian tag for evaluating model parameters and forcing terms. Comparisons to Lagrangian traces and to RBCM measurements led to the inclusion of "wall" layer boundary conditions in the model. Without this layer, modeled currents seriously underestimated measured currents. Vector correlations between wind stress and measured currents were high with average veering suggestive of Ekman dynamics at a site offshore of the entrance to Chesapeake Bay. At a shallower site, correlations were relatively high, but topography or coastline guidance was strong.

  1. Remote sensing operations (multispectral scanner and photographic) in the New York Bight, 22 September 1975

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.; Hall, J. B., Jr.

    1977-01-01

    Ocean dumping of waste materials is a significant environmental concern in the New York Bight. One of these waste materials, sewage sludge, was monitored in an experiment conducted in the New York Bight on September 22, 1975. Remote sensing over controlled sewage sludge dumping included an 11-band multispectral scanner, fiver multispectral cameras and one mapping camera. Concurrent in situ water samples were taken and acoustical measurements were made of the sewage sludge plumes. Data were obtained for sewage sludge plumes resulting from line (moving barge) and spot (stationary barge) dumps. Multiple aircraft overpasses were made to evaluate temporal effects on the plume signature.

  2. River plume patterns and dynamics within the Southern California Bight

    USGS Publications Warehouse

    Warrick, J.A.; DiGiacomo, P.M.; Weisberg, S.B.; Nezlin, N.P.; Mengel, M.; Jones, B.H.; Ohlmann, J.C.; Washburn, L.; Terrill, E.J.; Farnsworth, K.L.

    2007-01-01

    Stormwater river plumes are important vectors of marine contaminants and pathogens in the Southern California Bight. Here we report the results of a multi-institution investigation of the river plumes across eight major river systems of southern California. We use in situ water samples from multi-day cruises in combination with MODIS satellite remote sensing, buoy meteorological observations, drifters, and HF radar current measurements to evaluate the dispersal patterns and dynamics of the freshwater plumes. River discharge was exceptionally episodic, and the majority of storm discharge occurred in a few hours. The combined plume observing techniques revealed that plumes commonly detach from the coast and turn to the left, which is the opposite direction of Coriolis influence. Although initial offshore velocity of the buoyant plumes was ∼50 cm/s and was influenced by river discharge inertia (i.e., the direct momentum of the river flux) and buoyancy, subsequent advection of the plumes was largely observed in an alongshore direction and dominated by local winds. Due to the multiple day upwelling wind conditions that commonly follow discharge events, plumes were observed to flow from their respective river mouths to down-coast waters at rates of 20–40 km/d. Lastly, we note that suspended-sediment concentration and beam-attenuation were poorly correlated with plume salinity across and within the sampled plumes (mean r2=0.12 and 0.25, respectively), while colored dissolved organic matter (CDOM) fluorescence was well correlated (mean r2=0.56), suggesting that CDOM may serve as a good tracer of the discharged freshwater in subsequent remote sensing and monitoring efforts of plumes.

  3. Chlorinated hydrocarbons in flatfishes from the Southern California, USA, Bight

    SciTech Connect

    Schiff, K.; Allen, M.J.

    2000-06-01

    Although inputs of chlorinated hydrocarbon compounds to the Southern California Bight (SCB) are presently low, historical deposits represent a source of bioaccumulation potential to sediment-associated fauna. To assess this bioaccumulation potential, 14 chlorinated hydrocarbon classes were measured in livers of three species of flatfish collected from 63 randomly selected sites on the coastal shelf between Point Conception and the United States-Mexico international border. Tissue contamination was widespread throughout the SCB, but was limited to just two chlorinated hydrocarbon classes. Virtually 100% of Pacific sanddab (Citharichthys sordidus) and longfin sanddab (Citharichthys xanthostigma) populations were estimated to be contaminated with dichlorodiphenyltrichloroethane (total DDT = sum of o.p{prime} and p,p{prime} isomers of DDT + dichlorodiphenyldichloroethylene [DDE] + dichlorodiphenyldichloroethane [DDD]) and/or polychlorinated biphenyls (total PCBs). Total DDT also contaminated the majority (64%) of the Dover sole (Microstomus pacificus) population in the SCB. Total PCB measurements in tissues of SCB flatfish were dominated by 12 congeners (52, 66, 87, 101, 105, 118, 128, 138, 153, 170, 180, and 187), which averaged 95% of the combined mass of the 27 congeners analyzed. Sediment concentrations accounted for most of the variability observed in tissue concentrations for 8 of these 12 congeners and total PCBs. Normalized sediment concentrations were also significantly correlated to normalized tissue concentrations for total DDT and p,p{prime}-DDE. Tissue concentrations measured in this study from reference areas of the SCB were compared to tissue concentrations measured form reference areas in studies conducted in 1977 and 1985. Total DDT and total PCB liver concentrations were found to have decreased one to two orders of magnitude in pacific and longfin sanddabs between 1985 and 1994. Total DDT and total PCB liver concentrations decreased 5- to 35-fold in

  4. Phytoplankton Assemblage Patterns in the Southern Mid-Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Makinen, Carla; Moisan, Tiffany A. (Editor)

    2012-01-01

    As part of the Wallops Coastal Oceans Observing Laboratory (Wa-COOL) Project, we sampled a time-series transect in the southern Mid-Atlantic Bight (MAB) biweekly. Our 2-year time-series data included physical parameters, nutrient concentrations, and chlorophyll a concentrations. A detailed phytoplankton assemblage structure was examined in the second year. During the 2-year study, chlorophyll a concentration (and ocean color satellite imagery) indicated that phytoplankton blooms occurred in January/February during mixing conditions and in early autumn under stratified conditions. The chlorophyll a concentrations ranged from 0.25 microgram 1(exp -1) to 15.49 microgram 1(exp -1) during the 2-year period. We were able to discriminate approximately 116 different species under phase contrast microscopy. Dominant phytoplankton included Skeletonema costatum, Rhizosolenia spp., and Pseudo-nitzschia pungens. In an attempt to determine phytoplankton species competition/succession within the assemblage, we calculated a Shannon Weaver diversity index for our diatom microscopy data. Diatom diversity was greatest during the winter and minimal during the spring. Diatom diversity was also greater at nearshore stations than at offshore stations. Individual genera appeared patchy, with surface and subsurface patches appearing abruptly and persisting for only 1-2 months at a time. The distribution of individual species differed significantly from bulk variables of the assemblage (chlorophyll a ) and total phytoplankton assemblage (cells), which indicates that phytoplankton species may be limited in growth in ways that differ from those of the total assemblage. Our study demonstrated a highly diverse phytoplankton assemblage throughout the year, with opportunistic species dominating during spring and fall in response to seasonal changes in temperature and nutrients in the southern MAB.

  5. Ecological Condition of Coastal Ocean Waters Along the U.S. Mid-Atlantic Bight: 2006

    EPA Science Inventory

    This report presents the results of an assessment of ecological condition in coastal-ocean waters of the U.S. mid-Atlantic Bight (MAB), along the U.S. continental shelf from Cape Cod, MA and Nantucket Shoals to the northeast to Cape Hatteras to the south, based on sampling conduc...

  6. Dispersal of river sediment in the Southern California Bight

    USGS Publications Warehouse

    Warrick, J.A.; Farnsworth, K.L.

    2009-01-01

    (??10 cm/s) and only with adequate wave-generated shear stress and sediment loading. Calleguas Creek is unique in that it discharges directly into a steepsloped canyon (greater than 0.1) that should allow for violent auto-suspending gravity currents. In light of this, only one shelf setting-the Santa Clara and Ventura-has considerable Holocene sediment accumulation (exceeding 60 m), and here we show that the morphology of this shelf is very similar to an equilibrium shape predicted by gravity-current sediment transport. Thus, we conclude that a wide distribution of river-shelf settings occur in the Southern California Bight, which will directly influence sediment dispersal processes-both dilute suspended and gravity-current transport-and sediment-accumulation patterns. ?? 2009 The Geological Society of America.

  7. Shelf-Slope Exchange in the Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Goodman, P. J.; Wilkin, J.

    2004-12-01

    A high resolution model (ROMS, the Regional Ocean Modeling System) of U.S. East Coast circulation from Newfoundland to Cuba is used to explore features of alongshelf freshwater transport, residence time, and shelf-sea/deep-ocean exchange. The focus of the analysis is the Mid-Atlantic Bight (MAB) shelf-slope system which, like continental shelves throughout the world, contributes to the oceanic budgets of heat, salt, and fresh water. In addition, the "continental shelf pump" transfers carbon from the atmosphere to the deep ocean through fluxes of dissolved organic carbon and particulate organic carbon off the shelves. Solar radiation, evaporation, rainfall, riverine input, gas exchange with the atmosphere, and biological production all modify the character of shelf waters. In the MAB, the shelf-slope front separates shallow coastal waters from slope waters and the Gulf Stream, extending residence times on the shelf and maintaining coastal salinities at significantly lower levels than those offshore. The southwestward coastal mean flow exchanges weakly with slope waters along most of the MAB, with the strongest offshore flow occurring at Cape Hatteras where much of the flow is entrained into the Gulf Stream front. The shelf circulation is influenced by input from the Hudson and Delaware Rivers and Chesapeake Bay. Along the shelf break, exchange is modulated by warm-core rings from the Gulf Stream and variability of the shelf-break front. Key features of the seasonal circulation such as the MAB "Cold Pool" are captured by the simulation. Measurements suggest that DOC in shelf and shallow slope waters of the MAB include both old marine carbon and a young terrestrial-riverine-estuarine component, and these carbon cycling processes are being studied with a companion primary production, nitogen and carbon cycle model directly coupled to ROMS. Results showing salinity, idealized dye and Lagrangian float tracking results from a ROMS simulation of the MAB shelf circulation

  8. The recirculation of the intermediate western boundary current at the Tubarão Bight - Brazil

    NASA Astrophysics Data System (ADS)

    Costa, Vladimir S.; Mill, Guilherme N.; Gabioux, Mariela; Grossmann-Matheson, Guisela S.; Paiva, Afonso M.

    2017-02-01

    Lagrangian floats and current meter measurements from two moored arrays are analyzed, in combination with altimetry data, in order to investigate the recirculation of Antarctic Intermediate Waters (AAIW), and of the Intermediate Western Boundary Current (IWBC) at the Tubarão Bight, in the vicinity of the Vitória-Trindade Ridge (VTR), Brazil. Results from a high-resolution numerical simulation provide a complementary view of the flow at intermediate and surface levels. The data depict a topographically-induced cyclonic recirculation at intermediate levels, and five Argo floats are successively trapped inside the bight for two-and-a-half years, performing a total of 10 closed clockwise gyres during this period of time. In situ measurements at the western side of the bight show an intense alongshore flow at intermediate levels, with averaged velocities at 800 m of 30 cm/s, and peak velocities exceeding 50 cm/s, magnitudes comparable to the Brazil Current (BC) flow at surface levels. The recirculation extends from at least 1000 m deep up to 370 m, reaching sometimes depths as shallow as 150 m, but is mostly uncoupled from the surface flow during the one-and-a-half year long current meter record. Three different flow patterns are observed, and simulated, at surface levels inside the bight during the time the recirculation is well established at intermediate levels: a shallow cyclonic circulation, somewhat akin to the Vitória Eddy; a recurrent anticyclonic flow that encompasses the entire bight; and a southwestward-oriented circulation, associated with the BC being reorganized in a coherent flow after negotiating its way through the VTR channels. A significant portion (about 50% according to the model) of the inflow of intermediate waters recirculates, enhancing the flow of the IWBC within the bight, and increasing the age of AAIW that will eventually cross the VTR on its way to lower latitudes. Although the data are not conclusive about a preferential pathway of the

  9. Towards an integrated view of benthic and pelagic processes in the southern North Sea (German Bight)

    NASA Astrophysics Data System (ADS)

    Friedrich, Jana; van Beusekom, Justus; Neumann, Andreas; Naderipour, Celine

    2015-04-01

    The North Sea can be classified as a semi-enclosed shelf on the western-European continent. Atlantic influences are mainly through the Fair Isle current Channel in the North, and through the Strait of Dover in the South. An anti-clockwise circulation prevails, driven by mainly semi-diurnal tides and winds. The German Bight is located in the south-eastern part of the North Sea, and is strongly influenced by continental rivers. The outflow from the rivers Scheldt, Maas and Rhine is carried towards the German Bight with the residual currents. The German rivers Ems, Weser and Elbe directly debouche into the German Bight. On the shallow shelf, the water column is completely mixed by tidal forces and wind, largely preventing downward flux of particles and instead fostering temporary deposition and resuspension, which influences benthic mineralization. Hence, complex interactions between pelagic and benthic processes occur. Previous budget calculations indicate that the nutrient inventory has to be processed several times to support observed primary production, and, depending on water depth; only 10-20% remineralisation occurs in sediments of the German Bight whereas about 50% of organic matter is remineralised in the sediments of the shallow Wadden Sea. In this presentation, we use in-situ and ex-situ field data on pelagic and benthic oxygen respiration and benthic nutrient fluxes to assess the intense mineralization activity in the German Bight, the partitioning of benthic and pelagic processes and the factors influencing organic matter mineralization. Measurements of pelagic oxygen respiration based on Winkler titration, in-situ benthic oxygen uptake measurements based on flux-chamber landers and ex-situ incubations of intact sediment cores revealed that benthic remineralisation rates are about an order of magnitude smaller than pelagic rates, in agreement with previous budget estimates. Both benthic and pelagic oxygen respiration show a strong seasonality; with higher

  10. The ecology of rubble structures of the South Atlantic Bight: A community profile. [Jetties

    SciTech Connect

    Hay, M.E.; Sutherland, J.P.

    1988-09-01

    This community profile provides an introduction to the ecology of the communities living on and around rubble structures in the South Atlantic Bight (Cape Hatteras to Cape Canaveral). The most prominent rubble structures in the bight are jetties built at the entrances to major harbors. After an initial discussion of the various kinds of rubble structures and physical factors that affect the organisms associated with them, the major portion of the text is devoted to the ecology of rubble structure habitats. Community composition, distribution, seasonality, and the recruitment patterns of the major groups of organisms are described. The major physical and biological factors affecting the organization of intertidal, sunlit subtidal, and shaded subtidal communities are presented and the potential effects of complex interactions in structuring these communities are evaluated. The profile concludes with a general review of the effects of rubble structures on nearshore sediment dynamics and shoreline evolution. 295 refs., 33 figs., 4 tabs.

  11. MOCHA: A three dimensional climatology of salinity and temperature of the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Fleming, N. E.; Wilkin, J. L.

    2012-12-01

    A 3-D climatology of the salinity and temperature of the Middle Atlantic Bight (MAB) is developed to provide a synthesis of observations and a tool for understanding the heat and freshwater budgets, and dynamics, of this area. 150 years of historical data are quality controlled and combined by weighted least squares to a 3-D grid encompassing the Middle Atlantic Bight and the Gulf of Maine, including Chesapeake Bay, Delaware Bay, and the Hudson River Estuary. Half degree grid spacing, along with weighted fitting in horizontal distance, vertical distance, time and bathymetry provide highly resolved maps for each month of the year that compare well to independent data sets. Features such as the MAB "Cold Pool", and the seasonal cycle of heating and cooling are clearly visible throughout the months.

  12. MOCHA: A three dimensional climatology of salinity and temperature of the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Fleming, N. E.; Wilkin, J. L.

    2013-05-01

    A 3-D climatology of the salinity and temperature of the Middle Atlantic Bight (MAB) is developed to provide a synthesis of observations and a tool for understanding the heat and freshwater budgets, and dynamics, of this area. 150 years of historical data are quality controlled and combined by weighted least squares to a 3-D grid encompassing the Middle Atlantic Bight and the Gulf of Maine, including Chesapeake Bay, Delaware Bay, and the Hudson River Estuary. Half degree grid spacing, along with weighted fitting in horizontal distance, vertical distance, time and bathymetry provide highly resolved maps for each month of the year that compare well to independent data sets. Features such as the MAB "Cold Pool", and the seasonal cycle of heating and cooling are clearly visible throughout the months.

  13. Ship and satellite bio-optical research in the California Bight

    NASA Technical Reports Server (NTRS)

    Smith, R. C.; Baker, K. S.

    1982-01-01

    Mesoscale biological patterns and processes in productive coastal waters were studied. The physical and biological processes leading to chlorophyll variability were investigated. The ecological and evolutionary significance of this variability, and its relation to the prediction of fish recruitment and marine mammal distributions was studied. Seasonal primary productivity (using chlorophyll as an indication of phytoplankton biomass) for the entire Southern California Bight region was assessed. Complementary and contemporaneous ship and satellite (Nimbus 7-CZCS) bio-optical data from the Southern California Bight and surrounding waters were obtained and analyzed. These data were also utilized for the development of multi-platform sampling strategies and the optimization of algorithms for the estimation of phytoplankton biomass and primary production from satellite imagery.

  14. Synoptic thermal and oceanographic parameter distributions in the New York Bight Apex

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.; Bahn, G. S.; Thomas, J. P.

    1981-01-01

    Concurrent surface water measurements made from a moving oceanographic research vessel were used to calibrate and interpret remotely sensed data collected over a plume in the New York Bight Apex on 23 June 1977. Multiple regression techniques were used to develop equations to map synoptic distributions of chlorophyll a and total suspended matter in the remotely sensed scene. Thermal (which did not have surface calibration values) and water quality parameter distributions indicated a cold mass of water in the Bight Apex with an overflowing nutrient-rich warm water plume that originated in the Sandy Hook Bay and flowed south near the New Jersey shoreline. Data analysis indicates that remotely sensed data may be particularly useful for studying physical and biological processes in the top several metres of surface water at plume boundaries.

  15. Quantitative mapping of suspended solids in wastewater sludge plumes in the New York Bight apex

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.; Duedall, I. W.; Glasgow, R. M.; Proni, J. R.; Nelsen, T. A.

    1977-01-01

    The purpose of this investigation was to apply the previously reported methodology to remotely sensed data that were collected over wastewater sludge plumes in the New York Bight apex on September 22, 1975. Spectral signatures were also determined during this study. These signatures may be useful in the specific identification of sludge plumes, as opposed to other plumes such as those created by the disposal of industrial acid wastes.

  16. Biological processes in the water column of the south Atlantic bight: Zooplankton responses: Progress report

    SciTech Connect

    Paffenhoefer, G.A.

    1987-12-16

    The studies on which we report in the following segments represent interdisciplinary efforts to understand interactions of physical, chemical and biological processes on the southeastern continental shelf of the USA. The Georgia Bight Experiment was designed to determine the physical forces responsible for upwelling on the northeastern Florida and Georgia shelf during summer, trajectories and fate of those upwellings, and major chemical and biological processes therein. 5 refs.

  17. Modeling of Habitat and Foraging Behavior of Beaked Whales in the Southern California Bight

    DTIC Science & Technology

    2012-09-30

    such as coastal, canyons, basins, islands, shelf break, seamounts and open ocean, covering a broad range of habitats. Acoustic signal processing for...Cross Seamount , Pearl and Hermes Reef, and a site in the Southern California Bight near the shelf break had the highest overall beaked whale...species producing signals first described at Cross Seamount (BWC), detected broadly throughout the Pacific Islands region, consistently showed a strong

  18. On the occurrence of the thumbnail crab Thia scutellata in the inner German Bight

    NASA Astrophysics Data System (ADS)

    Türkay, Michael

    2011-06-01

    The thumbnail crab Thia scutellata occurs in the German Bight in at least two stable populations: at Borkum Riff and Loreley Bank. The western (Borkum Riff) population is larger than the eastern (Loreley Bank) one, probably because of the more frequent ingression of south-western warmer water along the Dutch coast. The sediments of these two localities are well-sorted middle sands with a very low amount of finer fractions.

  19. A numerical model of the time-dependent wintertime circulation of the New York Bight

    NASA Astrophysics Data System (ADS)

    Hsueh, Y.; Chen, K. C.; Marmorino, G. O.

    1984-01-01

    The time-dependent flow in the New York Bight from March 7 to April 30, 1975, is calculated from approximations to the barotropic vorticity equation subject to forcing by winds observed at the John F. Kennedy airport and by an upstream flow across the Long Island shelf. Comparisons of major axis velocities to observations throughout the bight show reasonable agreement. There is also considerable model skill in the prediction of alongshore variations in the major axis velocity with relatively low absolute errors. In general, associated with northeastward winds are northeastward shelf flows and upvalley currents in the Hudson Shelf Valley (HSV). Downvalley flows in the HSV occur when the northeastward wind abates and the flow on the shelf turns southwestward. The mechanism responsible for the behavior of the valley flow appears to be topographic steering with moderation due to bottom friction. The time rate of change of relative vorticity does not appear to have large net effect over the duration of an event Consequently, steady state models represent well the dynamics for an event-averaged flow. Discrepancies between model results and observation suggest that there is indeed a southwestward pressure gradient force operating in the New York Bight, and an adiabatic pressure condition offshore may be an over simplification that need be removed.

  20. Long-term marine litter monitoring in the remote Great Australian Bight, South Australia.

    PubMed

    Edyvane, K S; Dalgetty, A; Hone, P W; Higham, J S; Wace, N M

    2004-06-01

    The Anxious Bay beach litter clearance is the longest running annual survey of ocean-based litter in Australia. It's remoteness from centres of human population and location (with respect to prevailing winds and currents) make it an ideal place for monitoring ocean or ship-based litter in Australia's southern oceans and particularly, the Great Australian Bight. Over the 1991-1999 period, a large but gradual decline in the amount of beach washed litter was recorded (with minor peaks recorded during the 1992 and 1994 surveys). Beach washed litter decreased by approximately 86%, from 344 kg recorded in 1991 (13.2 kg/km) to 49 kg in 1999 (i.e. 1.9 kg/km), reaching a maximum of 390 kg in 1992 (or 15 kg/km of beach). However, a sharp increase in litter was recorded in 2000 (i.e. 252 kg or 9.7 kg/km). This increase in litter yield in 2000 is probably due to stronger than average onshore surface flow (or Ekman Transport) in the western Eyre Peninsula and Bight region. Prior to the survey in 2000, the results appeared to indicate that ocean litter on Anxious Bay beach was beginning to level out at around 50-70 kg/year (i.e. 2-3 kg/km). As the beach surveys involve the assumption that the beach is completely cleared of litter, this may represent a baseline level for ocean-based litter in the region. The yields and type of litter collected from the annual survey indicates that the majority of litter washed ashore originates from commercial fishing activities within the Great Australian Bight. Most of the fishing-related litter was directly sourced to the Southern Rock Lobster Fishery (i.e. bait buckets, baskets, pots), the Great Australian Bight Trawl Fishery (i.e. codends, trawl nets) and the Southern Shark Fishery (i.e. monofilament gillnets and longlines). Between 1994 and 1999, large reductions were observed in the amount of bait straps (77% reduction), lobster bait baskets/buckets (86% reduction), nets/ropes (62% reduction) and floats/buoys (83% reduction). Significantly

  1. Water mass analysis and alongshore variation in upwelling intensity in the eastern Great Australian Bight

    NASA Astrophysics Data System (ADS)

    McClatchie, Sam; Middleton, John F.; Ward, Tim M.

    2006-08-01

    A study of climatological and conductivity-temperature-depth (CTD) data for 2004 is made to provide a conceptual model of upwelling for the eastern region of the Great Australian Bight. In particular, the data and other studies provide strong evidence that shelf break upwelling is confined to the southwest Kangaroo Island region and does not occur farther to the west off the Eyre Peninsula. Rather, the upwelled water is likely to remain in a Kangaroo Island "pool" until subsequent upwelling events draw the water to the shallower and surface coastal regions of the eastern Bight. In this manner the surface upwelling apparent off the Bonney Coast, Kangaroo Island, and the eastern Great Australian Bight (GAB) can appear to be simultaneous. Moreover, it appears likely that the water within the Kangaroo Island pool remains nutrient rich. Support for this model comes from CTD sections collected in 2004 that show that the upwelled signal (cool, <17°C fresher, <35.6 dense, σt > 26 kg m-3) diminishes in width and intensity with increasing distance from Kangaroo Island. The pattern of fluorescence is similar to that for temperature in the upwelled plume and indicates that the Kangaroo Island pool remains nutrient rich. Relatively low oxygen concentrations may indicate a previous bloom. The warmest water is found near the shelf break along with very low values of fluorescence and relatively higher levels of oxygen suggesting nutrient-limited growth of phytoplankton. These data also support the notion that the upwelled nutrient-rich water is supplied from the Kangaroo Island pool and not by shelf break upwelling in the eastern GAB. Anomalously salty and fresh water is identified as resulting from evaporation in coastal bays and groundwater aquifer discharge.

  2. Using species-specific paleotemperature equations with foraminifera: A case study in the Southern California Bight

    USGS Publications Warehouse

    Bemis, B.E.; Spero, H.J.; Thunell, R.C.

    2002-01-01

    Species-specific paleotemperature equations were used to reconstruct a record of temperature from foraminiferal ??18O values over the last 25 kyr in the Southern California Bight. The equations yield similar temperatures for the ??18O values of Globigerina bulloides and Neogloboquadrina pachyderma. In contrast, applying a single paleotemperature equation to G. bulloides and N. pachyderma ??18O yields different temperatures, which has been used to suggest that these species record the surface-to-thermocline temperature gradient. In Santa Barbara Basin, an isotopically distinct morphotype of G. bulloides dominates during glacial intervals and yields temperatures that appear too cold when using a paleotemperature equation calibrated for the morphotype common today. When a more appropriate paleotemperature equation is used for glacial G. bulloides, we obtain more realistic glacial temperatures. Glacial-interglacial temperature differences (G-I ??T) calculated in the present study indicate significant cooling (??? 8-10??C) throughout the Southern California Bight during the last glacial maximum (LGM). The magnitude of glacial cooling varies from ???8??C near the middle of the Southern California Bight (Tanner Basin and San Nicolas Basin) to ???9??C in the north (Santa Barbara Basin) and ???9.5-10??C in the south (Velero Basin and No Name Basin). Our temperature calculations agree well with previous estimates based on the modern analog technique. In contrast, studies using N. pachyderma coiling ratios, U37k??? indices, and transfer functions esfimate considerably warmer LGM temperatures and smaller G-I ??T. ?? 2002 Elsevier Science B.V. All rights reserved.

  3. A population study of the shrimp Crangon allmanni in the German Bight

    NASA Astrophysics Data System (ADS)

    Blahudka, Sabine; Türkay, Michael

    2002-09-01

    The only reproducing population of Crangon allmanni within the German Bight is in the Helgoland Trench (HTR), a depression of more than 50 m depth south of Helgoland. In coastal and shallower offshore waters the shrimp is much rarer and is recorded in higher numbers only in early spring when the water is still cold. The life cycle of the HTR population lasts for about 1.5 years maximum. Recruitment takes place in summer, and these recruits form the reproducing population of the next year. The shrimps are sensitive to environmental stress and are therefore good indicators of environmental changes.

  4. Contaminant trends in the Southern California Bight: Inventory and assessment. Technical memo

    SciTech Connect

    Mearns, A.J.; Matta, M.; Shigenaka, G.; MacDonald, D.; Buchman, M.

    1991-10-01

    The document is one of a series of regional reports summarizing existing information on contaminants measured by NOAA's National Status and Trends (NS and T) Program. It describes existing data for documenting the geographic distribution and long-term trends of 17 groups of contaminants in sediments, mussels, fish, and other species of the Southern California Bight. It also provides a guide to contaminant monitoring data sets covering samples collected over the past 50 years. Also reviewed were 10 trace elements, organotin compounds, PAHs, PCBs, and several pesticides.

  5. Natural feeding rates of Centropages typicus females in the New York Bight

    SciTech Connect

    Dagg, M.J.; Grill, D.W.

    1980-01-01

    Based on measurements of the removal rate of small particles from natural seawater,the ingestion rate of adult females of the copepod Centropages typicus is almost always less than maximal. A survey of particle concentrations in the New York Bight indicated that the concentrations used in our feeding experiments were representative of concentrations encountered by this species. In addition to the particle removal method, a gut fluorescence method was used to calculate natural ingestion rates of phytoplankton particles. Comparable rates resulted from both methods. We believe that for this organism, ingestion rates are closely related to food quality because the range of natural food concentrations is rather narrow.

  6. Remote Versus Local Forcing of Chlorophyll Variability in the South Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Signorini, Sergio R.; McClain, Charles R.

    2006-01-01

    This TM documents results of analyses addressing the local versus remote forcing of chlorophyll variability on the shelf and slope regions of the South Atlantic Bight (SAB) based on satellite-derived products and a limited amount of in situ data. This study is part of a larger multi-disciplinary, multi-institutional effort to study the Eastern U.S. Continental Shelf carbon budget (U.S. Eastern Continental Shelf Carbon Budget: Modeling, Data Assimilation, and Analysis, U.S. ECoS), a project funded by the NASA Earth System Enterprise Interdisciplinary Science Program that started in the summer of 2004.

  7. Tidal inlet processes and deposits along a low energy coastline: easter Barataria Bight, Louisiana

    SciTech Connect

    Moslow, T.F.; Levin, D.R.

    1985-01-01

    Historical, seismic and vibracore data were used to determine the geologic framework of sand deposits along the predominantly muddy coastline of eastern Barataria Bight, Louisiana. Three inlet types with distinct sand body geometries and morphologies were identified and are found 1) at flanking barrier island systems spread laterally across the front of interdistributary bays; 2) in old distributary channels; 3) at overwash breaches; or 4) combination of these. Barataria Bight, a sheltered barrier island shoreline embayment with limited sand supply, minimal tidal range (36 cm) and low wave energies (30 cm) can be used to show examples of each inlet type. Barataria Pass and Quatre Bayou Pass are inlets located in old distributary channels. However, Barataria Pass has also been affected by construction between barrier islands. Pass Ronquille is located where the coastline has transgressed a low area in the delta plain. This breach is situated in a hydraulically efficient avenue between the Gulf and Bay Long behind it. Pass Abel is a combination of a low-profile barrier breach and the reoccupation of an old distributary channel. Shelf and shoreline sands are reworked from abandoned deltaic distributaries and headlands. Inner shelf sands are concentrated in thick (10 m) shore-normal relict distributary channels with fine grained cross-bedded and ripple laminated sand overlain by burrowed shelf muds. Shoreface sand deposits occur as 2-3 m thick, fine-grained, coarsening upward and burrowed ebb-tidal delta sequences and shore-parallel relict tidal inlet channels filled through lateral accretion.

  8. Heavy-Metal and Antibiotic Resistance in the Bacterial Flora of Sediments of New York Bight

    PubMed Central

    Timoney, J. F.; Port, Jennifer; Giles, Janis; Spanier, J.

    1978-01-01

    The New York Bight extends seaward some 80 to 100 miles (ca. 129 to 161 km) from the Long Island and New Jersey shorelines to the edge of the continental shelf. Over 14 × 106 m3 of sewage sludge, dredge spoils, acid wastes, and cellar dirt are discharged into this area each year. Large populations of Bacillus sp. resistant to 20 μg of mercury per ml were observed in Bight sediments contaminated by these wastes. Resistant Bacillus populations were much greater in sediments containing high concentrations of Hg and other heavy metals than in sediments from areas further offshore where dumping has never been practiced and where heavy-metal concentrations were found to be low. Ampicillin resistance due mainly to β-lactamase production was significantly (P < 0.001) more frequent in Bacillus strains from sediments near the sewage sludge dump site than in similar Bacillus populations from control sediments. Bacillus strains with combined ampicillin and Hg resistances were almost six times as frequent at the sludge dump site as in control sediments. This observation suggests that genes for Hg resistance and β-lactamase production are simultaneously selected for in Bacillus and that heavy-metal contamination of an ecosystem can result in a selection pressure for antibiotic resistance in bacteria in that system. Also, Hg resistance was frequently linked with other heavy-metal resistances and, in a substantial proportion of Bacillus strains, involved reduction to volatile metallic Hg (Hg°). PMID:727779

  9. Geology and geochemistry of the Geyser Bight Geothermal Area, Umnak Island, Aleutian Islands, Alaska

    SciTech Connect

    Nye, C.J. . Geophysical Inst. Alaska Dept. of Natural Resources, Fairbanks, AK . Div. of Geological and Geophysical Surveys); Motyka, R.J. . Div. of Geological and Geophysical Surveys); Turner, D.L. . Geophysical Inst.); Liss, S.A. (Alaska Dept. of Natural Resources, Fairba

    1990-10-01

    The Geyser Bight geothermal area is located on Umnak Island in the central Aleutian Islands. It contains one of the hottest and most extensive areas of thermal springs and fumaroles in Alaska, and is only documented site in Alaska with geysers. The zone of hot springs and fumaroles lies at the head of Geyser Creek, 5 km up a broad, flat, alluvial valley from Geyser Bight. At present central Umnak is remote and undeveloped. This report describes results of a combined program of geologic mapping, K-Ar dating, detailed description of hot springs, petrology and geochemistry of volcanic and plutonic rock units, and chemistry of geothermal fluids. Our mapping documents the presence of plutonic rock much closer to the area of hotsprings and fumaroles than previously known, thus increasing the probability that plutonic rock may host the geothermal system. K-Ar dating of 23 samples provides a time framework for the eruptive history of volcanic rocks as well as a plutonic cooling age.

  10. Wind-forced dispersion of blue crab larvae in the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Johnson, Donald R.

    Blue crab larvae are advected out of Middle Atlantic Bight estuaries immediately after spawning occurs in the estuary entrance. For the next 30 to 50 days the larvae are found offshore and mainly at the surface where they are influenced by wind-driven currents. Using a previously derived circulation model and winds from Norfolk (VA) airport, a backward trace is made from where relatively dense concentrations of megalopae were found in the Chesapeake Bight during 1983 to a point of origin (spawning). During 1983, the megalopae encountered on the shelf had their origin in Chesapeake Bay and took, at minimum, 31 to 36 days to grow to the megalopae stage. Wind forcing dominated the inner shelf region in the summer of 1983 and the resulting dispersion of Chesapeake Bay megalopae occurred briefly in the southern sector early in the season, but toward the northern sector over most of the season. Although no firm conclusions could be drawn regarding the mechanism for return, it did not seem likely that wind advection back to the point of origin would be effective.

  11. Blue and Fin Whale Habitat Modeling from Long-Term Year-Round Passive Acoustic Data from the Southern California Bight

    DTIC Science & Technology

    2014-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Blue and Fin Whale Habitat Modeling from Long-Term Year...predictive, year-round habitat models of the presence of calling blue and fin whales in the Southern California Bight, to facilitate Navy’s operational...calling blue and fin whales in the Southern California Bight (SCB). We will also investigate the scales over which blue and fin whales respond to their

  12. Validating a hydrodynamic framework for long-term modelling of the German Bight

    NASA Astrophysics Data System (ADS)

    Koesters, Frank; Pluess, Andreas; Heyer, Harro; Kastens, Marko; Sehili, Aissa

    2010-05-01

    The intention of the "AufMod" project is to set up a modelling framework for questions concerning the large-scale, long-term morphodynamic evolution of the German Bight. First a hydrodynamic model has been set up which includes the entire North Sea and a sophisticated representation of the German Bight. In a second step, simulations of sediment transport and morphodynamic changes will be processed. This paper deals with the calibration and validation process for the hydrodynamic model in detail. The starting point for "AufMod" was the aim to better understand the morphodynamic processes in the German Bight. Changes in bottom topography need to be predicted to ensure a safe and easy transport through the German waterways leading to ports at the German coast such as Hamburg and Bremerhaven. Within "AufMod" this question is addressed through a combined effort of gaining a comprehensive sedimentological and bathymetric data set as well as running different numerical models. The model is based on the numerical method UnTRIM (Casulli and Zanolli, 2002). The model uses an unstructured grid in the horizontal to provide a good representation of the complex topography. The spatial resolution increases from about 20 km in the North Sea to 20 m within the estuaries. The model forcing represents conditions for the year 2006 and consists of wind stress at the surface, water level elevation and salinity at the open boundaries as well as freshwater inflows. Temperature is not taken into account. For the model validation, there exists a large number of over 40 hydrodynamic monitoring stations which are used to compare modelled and measured data. The calibration process consists of adapting the tidal components at the open boundaries following the approach of Pluess (2003). The validation process includes the analysis of tidal components of water level elevation and current values as well as an analysis of tidal characteristic values, e.g. tidal low and high water. Based on these

  13. Remote sensing and spectral analysis of plumes from ocean dumping in the New York Bight Apex

    SciTech Connect

    Johnson, R.W.

    1980-05-01

    The application of the remote sensing techniques of aerial photography and multispectral scanning in the qualitative and quantitative analysis of plumes from ocean dumping of waste materials is investigated in the New York Bight Apex. Plumes resulting from the dumping of acid waste and sewage sludge were observed by Ocean Color Scanner at an altitude of 19.7 km and by Modular Multispectral Scanner and mapping camera at an altitude of 3.0 km. Results of the qualitative analysis of multispectral and photographic data for the mapping, location, and identification of pollution features without concurrent sea truth measurements are presented which demonstrate the usefulness of in-scene calibration. Quantitative distributions of the suspended solids in sewage sludge released in spot and line dumps are also determined by a multiple regression analysis of multispectral and sea truth data.

  14. Remote sensing and spectral analysis of plumes from ocean dumping in the New York Bight Apex

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.

    1980-01-01

    The application of the remote sensing techniques of aerial photography and multispectral scanning in the qualitative and quantitative analysis of plumes from ocean dumping of waste materials is investigated in the New York Bight Apex. Plumes resulting from the dumping of acid waste and sewage sludge were observed by Ocean Color Scanner at an altitude of 19.7 km and by Modular Multispectral Scanner and mapping camera at an altitude of 3.0 km. Results of the qualitative analysis of multispectral and photographic data for the mapping, location, and identification of pollution features without concurrent sea truth measurements are presented which demonstrate the usefulness of in-scene calibration. Quantitative distributions of the suspended solids in sewage sludge released in spot and line dumps are also determined by a multiple regression analysis of multispectral and sea truth data.

  15. Large-scale forcing impact on biomass variability in the South Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Signorini, Sergio R.; McClain, Charles R.

    2007-11-01

    The Gulf Stream western front (GSF) follows the shelf slope topography for a great extent of the South Atlantic Bight (SAB). Sub-surface intrusions of the Gulf Stream are known to provide nutrient-rich waters to the outer shelf regions of the SAB and, consequently, promote phytoplankton growth. These intrusions are much more frequent during summer and are responsible for a significant portion of the annual SAB shelf carbon production. Based on the analysis of satellite ocean color data, sea surface temperature (SST), sea surface height (SSH), and climatologic data sets, we present evidence for a connection between these Gulf Stream intrusions and the seasonal variability of the size and strength of the North Atlantic Subtropical Gyre (NASG). The intensity and frequency of intrusions depend on the proximity of the GSF to the shelf, which is modulated by the seasonal expansion and contraction of the NASG.

  16. Cephalopods and cetaceans as indicators of offshore bioavailability of cadmium off Central South Brazil Bight.

    PubMed

    Dorneles, Paulo Renato; Lailson-Brito, José; Dos Santos, Roberta Aguiar; Silva da Costa, Paulo Alberto; Malm, Olaf; Azevedo, Alexandre Freitas; Machado Torres, João Paulo

    2007-07-01

    Regarding Brazilian coast, industrial and urban developments are concentrated along Central South Brazil Bight. Samples from inshore and offshore species from the concerned area were analyzed, comprising 24 cetaceans (9 species) and 32 squids (2 species). Cadmium was determined by GFAAS and our results were in agreement with certified values (DOLT-2, NRCC). Mean cadmium concentration (in microg/g, wet weight) observed in the digestive gland of sexually mature Argentine short-finned squids (Illex argentinus) was 1002.9. To our knowledge this is the highest cadmium level ever reported for a cephalopod. Concerning cetaceans, our results include one of the highest renal cadmium concentrations described for striped dolphins (71.29 microg/g, wet weight). Anthropogenic action, upwelling and cannibalism of Argentine short-finned squid on the studied area are possible reasons for such remarkable cadmium concentrations.

  17. Stormwater runoff plumes in the Southern California Bight: A comparison study with SAR and MODIS imagery.

    PubMed

    Holt, Benjamin; Trinh, Rebecca; Gierach, Michelle M

    2017-02-23

    Stormwater runoff is the largest source of pollution in the Southern California Bight (SCB), resulting from untreated runoff and pollutants from urban watersheds entering the coastal waters after rainstorms. We make use of both satellite SAR and MODIS-Aqua ocean color imagery to examine two different components of runoff plumes, the surface slick and the sediment discharge. We expand on earlier satellite SAR studies by examining an extensive collection of multi-platform SAR imagery, spanning from 1992 to 2014, that provides a more comprehensive view of the plume surface slick characteristics, illustrated with distribution maps of the extent and flow direction of the plumes. The SAR-detected surface plumes are compared with coincident rain and runoff measurements, and with available measured shoreline fecal bacteria loads. We illustrate differences in the detection of SAR surface plumes with the sediment-related discharge plumes derived from MODIS imagery. A conceptual satellite stormwater runoff monitoring approach is presented.

  18. The fate of an immigrant: Ensis directus in the eastern German Bight

    NASA Astrophysics Data System (ADS)

    Dannheim, Jennifer; Rumohr, Heye

    2012-09-01

    We studied Ensis directus in the subtidal (7-16 m depth) of the eastern German Bight. The jack-knife clam that invaded in the German Bight in 1978 has all characteristics of a successful immigrant: Ensis directus has a high reproductive capacity (juveniles, July 2001: Amrumbank 1,914 m-2, Eiderstedt/Vogelsand: 11,638 m-2), short generation times and growths rapidly: maximum growth rates were higher than in former studies (mean: 3 mm month-1, 2nd year: up to 14 mm month-1). Ensis directus uses natural mechanisms for rapid dispersal, occurs gregariously and exhibits a wide environmental tolerance. However, optimal growth and population-structure annual gaps might be influenced by reduced salinity: at Vogelsand (transition area of Elbe river), maximum growth was lower (164 mm) than at the Eiderstedt site (outer range of Elbe river, L ∞ = 174 mm). Mass mortalities of the clams are probably caused by washout (video inspections), low winter temperature and strong storms. Ensis directus immigrated into the community finding its own habitat on mobile sands with strong tidal currents. Recent studies on E. directus found that the species neither suppresses native species nor takes over the position of an established one which backs up our study findings over rather short time scales. On the contrary, E. directus seems to favour the settlement of some deposit feeders. Dense clam mats might stabilise the sediment and function as a sediment-trap for organic matter. Ensis directus has neither become a nuisance to other species nor developed according to the `boom-and-bust' theory. The fate of the immigrant E. directus rather is a story of a successful trans-ocean invasion which still holds on 23 years after the first findings in the outer elbe estuary off Vogelsand.

  19. Modelling the seasonal occurrence and distribution of humanpathogenic bacteria within the German Bight, southern North Sea

    NASA Astrophysics Data System (ADS)

    Schakau, Vanessa; Lettmann, Karsten A.; Wolff, Jörg-Olaf

    2015-04-01

    In recent years, the occurrence of human-pathogenic bacteria of the genus Vibrio in the North Sea and the Baltic Sea has come into the focus of many marine research activities, as different Vibrio strains caused harmful infections, especially in summers 2003, 2006, 2010 and 2014. Furthermore, it is anticipated that under global warming conditions, the risk of the occurrence of human-pathogenic in summer season will increase very likely. To present knowledge temperature and salinity are the most powerful predictors of the occurrence of Vibrio spp. in coastal waters. However, studies support the interaction of human-pathogenic Vibrio spp. with different host and vector organisms like chitinous zooplankton or with predator organisms such as Vibrio-specific bacteriophages. A modeling system has been developed to understand and predict the occurrence and distribution of harmful Vibrio spp. within the North Sea with a special focus on the German Bight including the shallower Wadden Sea areas and the estuaries of Ems, Weser and Elbe. On the one hand, this modeling system is based on the unstructured-mesh hydrodynamic model FVCOM, which can predict the oceanic circulation and distributions of temperature and salinity within the German Bight for appropriate present and future climate conditions. On the other hand, a biological module has been attached, which can simulate the distribution and abundances of Vibrio spp.. In detail, apart from specific Vibrio strains, this biological module incorporates functional groups of phyto- and zooplankton and bacteriophages as potential host- and predator-organisms. In a first study, this modeling system has been applied to a hot summer season in 2006. It has been demonstrated that this system can reproduce the valid hydrodynamic conditions within the North Sea region of interest including temperature and salinity distribution patterns. In addition, reasonable temporal and spatial patterns of Vibrio abundances have been obtained.

  20. Sources of sediment to the coastal waters of the Southern California Bight

    USGS Publications Warehouse

    Warrick, J.A.; Farnsworth, K.L.

    2009-01-01

    The sources of sediment to the Southern California Bight were investigated with new calculations and published records of sediment fluxes, both natural and anthropogenic. We find that rivers are by far the largest source of sediment, producing over 10 ?? 106 t/yr on average, or over 80% of the sediment input to the Bight. This river flux is variable, however, over both space and time. The rivers draining the Transverse Ranges produce sediment at rates approximately an order of magnitude greater than the Peninsular Ranges (600-1500 t/km2/yr versus <90 t/km2/yr, respectively). Although the Transverse Range rivers represent only 23% of the total Southern California watershed drainage area, they are responsible for over 75% of the total sediment flux. River sediment flux is ephemeral and highly pulsed due to the semiarid climate and the influence of infrequent large storms. For more than 90% of the time, negligible amounts of sediment are discharged from the region's rivers, and over half of the post-1900 sediment load has been discharged during events with recurrence intervals greater than 10 yr. These rare, yet important, events are related to the El Ni??o-Southern Oscillation (ENSO), and the majority of sediment flux occurs during ENSO periods. Temporal trends in sediment discharge due to land-use changes and river damming are also observed. We estimate that there has been a 45% reduction in suspended-sediment flux due to the construction of dams. However, pre-dam sediment loads were likely artificially high due to the massive land-use changes of coastal California to rangeland during the nineteenth century. This increase in sediment production is observed in estuarine deposits throughout coastal California, which reveal that sedimentation rates were two to ten times higher during the nineteenth and twentieth centuries than during pre-European colonization. ?? 2009 The Geological Society of America.

  1. Analysis of High Spatial, Temporal, and Directional Resolution Recordings of Biological Sounds in the Southern California Bight

    DTIC Science & Technology

    2012-09-30

    insight into population- level structure and dynamics and trophic interactions of important food sources for certain marine mammal species The approach...understanding of the ecosystem of the Southern California Bight, a region containing both a high density of marine mammals and a high level of U.S...assessment in biologically sensitive areas and improved ecosystem modeling, and c) the application of the physics of excitable media to numerical

  2. Common trends in German Bight benthic macrofaunal communities: Assessing temporal variability and the relative importance of environmental variables

    NASA Astrophysics Data System (ADS)

    Ghodrati Shojaei, Mehdi; Gutow, Lars; Dannheim, Jennifer; Rachor, Eike; Schröder, Alexander; Brey, Thomas

    2016-01-01

    We examined long-term variability in the abundance of German Bight soft bottom macro-zoobenthos together with major environmental factors (sea surface temperature, winter NAO index, salinity, phosphate, nitrate and silicate) using one of the most comprehensive ecological long-term data sets in the North Sea (1981-2011). Two techniques, Min/Max Autocorrelation Factor Analysis (MAFA) and Dynamic Factor Analysis (DFA) were used to identify underlying common trends in the macrofaunal time series and the relationships between this series and environmental variables. These methods are particularly suitable for relatively short (> 15-25 years), non-stationary multivariate data series. Both MAFA and DFA identify a common trend in German Bight macrofaunal abundance i.e. a slight decrease (1981-mid-1990s) followed by a sharp trough in the late 1990s. Subsequently, scores increased again towards 2011. Our analysis indicates that winter temperature and North Atlantic Oscillation were the predominant environmental drivers of temporal variation in German Bight macrofaunal abundance. The techniques applied here are suitable tools to describe temporal fluctuations in complex and noisy multiple time series data and can detect distinct shifts and trends within such time series.

  3. A model of p, p'-DDE and total PCB bioaccumulation in birds from the Southern California Bight

    NASA Astrophysics Data System (ADS)

    Glaser, David; Connolly, John P.

    2002-05-01

    Pathways of p, p'-DDE and PCB transfer to three species of birds were characterized as part of the Southern California Bight Natural Resource Damage Assessment. Based upon analysis of the results of extensive field studies conducted by other investigators to characterize the dietary composition, foraging behavior, and contaminant levels in the predators and in their prey, 70-80 percent of the contaminant dose received by the peregrine falcon and 90-95 percent of the dose to the bald eagle originated within the Bight. Dynamic, mechanistic, bioenergetics-based bioaccumulation models for p, p'-DDE and PCBs were developed for both species. Measured contaminant levels in predator eggs were found to be quantitatively consistent with measured levels in their prey, providing support for the estimates of dietary composition and foraging behavior, and therefore for the characterization of contaminant sources. Based on the model, most of the contaminant dose to the bald eagles on Santa Catalina Island is accumulated from sea lion carrion, and, based on a model of female sea lion bioaccumulation described in a companion publication, much of the dose to the sea lion originates in the more highly contaminated regions of the Bight which include the Palos Verdes Shelf and Santa Monica Bay. The importance of non-local contaminant sources to the eagle was surprising, since the eagles are non-migratory and forage locally on Santa Catalina, and consume 90 percent fish, most of which are nearshore species. A third model constructed for the double-crested cormorant indicated that cormorants from Anacapa Island are likely to feed to some degree in the more highly contaminated regions of the Bight near the Palos Verdes Shelf. In contrast, the cormorants from Santa Barbara Island probably feed less intensively in the more contaminated regions of the Bight than previously thought. The model framework developed here is generally applicable. It can aid in predicting the course of natural

  4. Determination of shell deposition rates of Arctica islandica from the New York Bight using natural /sup 228/Ra and /sup 228/Th and bomb-produced /sup 14/C

    SciTech Connect

    Turekian, K.K.; Cochran, J.K.; Nozaki, Y.; Thompson, I.; Jones, D.S.

    1982-01-01

    Shell deposition rates of specimens of Arctica islandica (Mollusca: Bivalvia) from the New York Bight were determined using natural /sup 228/Ra and /sup 228/Th and bomb /sup 14/C. The specimens from deep (>55 m) offshore waters show annual growth banding. A shell obtained from the inner bight at <30-m depth seems to be younger than indicated by band counting.

  5. Impacts of stormwater runoff in the Southern California Bight: Relationships among plume constituents

    USGS Publications Warehouse

    Reifel, K.M.; Johnson, S.C.; DiGiacomo, P.M.; Mengel, M.J.; Nezlin, N.P.; Warrick, J.A.; Jones, B.H.

    2009-01-01

    The effects from two winter rain storms on the coastal ocean of the Southern California Bight were examined as part of the Bight '03 program during February 2004 and February-March 2005. The impacts of stormwater from fecal indicator bacteria, water column toxicity, and nutrients were evaluated for five major river discharges: the Santa Clara River, Ballona Creek, the San Pedro Shelf (including the Los Angeles, San Gabriel, and Santa Ana Rivers), the San Diego River, and the Tijuana River. Exceedances of bacterial standards were observed in most of the systems. However, the areas of impact were generally spatially limited, and contaminant concentrations decreased below California Ocean Plan standards typically within 2-3 days. The largest bacterial concentrations occurred in the Tijuana River system where exceedances of fecal indicator bacteria were noted well away from the river mouth. Maximum nitrate concentrations (~40 ??M) occurred in the San Pedro Shelf region near the mouth of the Los Angeles River. Based on the results of general linear models, individual sources of stormwater differ in both nutrient concentrations and the concentration and composition of fecal indicator bacteria. While nutrients appeared to decrease in plume waters due to simple mixing and dilution, the concentration of fecal indicator bacteria in plumes depends on more than loading and dilution rates. The relationships between contaminants (nutrients and fecal indicator bacteria) and plume indicators (salinity and total suspended solids) were not strong indicating the presence of other potentially important sources and/or sinks of both nutrients and fecal indicator bacteria. California Ocean Plan standards were often exceeded in waters containing greater than 10% stormwater (<28-30 salinity range). The median concentration dropped below the standard in the 32-33 salinity range (1-4% stormwater) for total coliforms and Enterococcus spp. and in the 28-30 salinity range (10-16% stormwater

  6. Spatial and temporal patterns in oxygen and nutrient fluxes in sediment of German Bight (North Sea)

    NASA Astrophysics Data System (ADS)

    Neumann, Andreas; Friedrich, Jana; van Beusekom, Justus; Naderipour, Céline

    2016-04-01

    The German Bight in the southern North Sea is affected by intensive anthropogenic exploitation. Over a century of intensive use by shipping, fishery, and input by polluted rivers has pushed the coastal ecosystem far from its pristine state. The nutrient load reached a maximum in the early 1990s (Amann et al. 2012), and implementation of environmental protection policies substantially decreased the riverine nutrient load. While the riverine input of pollutants has constantly reduced since then, new forms of sea exploitation emerge. The most noticeable example is the installation of more than 600 wind turbines over the past few years in the German EEZ, and additionally 1,200 are already planned. The impact of these installations on hydrology and biogeochemical cycles is largely unclear. In a series of monitoring cruises we repeatedly sampled the sediment at a set of monitoring stations, which represent all typical habitats of the German Bight. We deployed benthic landers for in-situ chamber incubations and performed ex-situ whole-core incubations to investigate the benthic fluxes of oxygen and nutrients, and their spatial and temporal variability. Our first results indicate that benthic nutrient recycling is more intense during summer than during winter, which suggests that biological processes contribute substantially to the recycling of nutrients. The fluxes of reactive nitrogen appear lower than observations from 1992 (Lohse et al. 1993), when riverine N loads were at their maximum (Amann et al. 2012). The comparison of our recent measurements with observations from the past decades will enable us to assess the effect of decreasing nutrient discharge into the coastal North Sea. Our results will further set a baseline for elucidating the impact of the massive installation of wind turbines in the near future. This study contributes to the NOAH project (North Sea; Observation and Assessment of Habitats). References Amann T., A. Weiss, and J. Hartmann (2012): Carbon

  7. Impacts of stormwater runoff in the Southern California Bight: Relationships among plume constituents

    NASA Astrophysics Data System (ADS)

    Reifel, Kristen M.; Johnson, Scott C.; DiGiacomo, Paul M.; Mengel, Michael J.; Nezlin, Nikolay P.; Warrick, Jonathan A.; Jones, Burton H.

    2009-08-01

    The effects from two winter rain storms on the coastal ocean of the Southern California Bight were examined as part of the Bight '03 program during February 2004 and February-March 2005. The impacts of stormwater from fecal indicator bacteria, water column toxicity, and nutrients were evaluated for five major river discharges: the Santa Clara River, Ballona Creek, the San Pedro Shelf (including the Los Angeles, San Gabriel, and Santa Ana Rivers), the San Diego River, and the Tijuana River. Exceedances of bacterial standards were observed in most of the systems. However, the areas of impact were generally spatially limited, and contaminant concentrations decreased below California Ocean Plan standards typically within 2-3 days. The largest bacterial concentrations occurred in the Tijuana River system where exceedances of fecal indicator bacteria were noted well away from the river mouth. Maximum nitrate concentrations (~40 μM) occurred in the San Pedro Shelf region near the mouth of the Los Angeles River. Based on the results of general linear models, individual sources of stormwater differ in both nutrient concentrations and the concentration and composition of fecal indicator bacteria. While nutrients appeared to decrease in plume waters due to simple mixing and dilution, the concentration of fecal indicator bacteria in plumes depends on more than loading and dilution rates. The relationships between contaminants (nutrients and fecal indicator bacteria) and plume indicators (salinity and total suspended solids) were not strong indicating the presence of other potentially important sources and/or sinks of both nutrients and fecal indicator bacteria. California Ocean Plan standards were often exceeded in waters containing greater than 10% stormwater (<28-30 salinity range). The median concentration dropped below the standard in the 32-33 salinity range (1-4% stormwater) for total coliforms and Enterococcus spp. and in the 28-30 salinity range (10-16% stormwater

  8. Exploring German Bight coastal morphodynamics based on modelled bed shear stress

    NASA Astrophysics Data System (ADS)

    Kösters, Frank; Winter, Christian

    2014-02-01

    The prediction of large-scale coastal and estuarine morphodynamics requires a sound understanding of the relevant driving processes and forcing factors. Data- and process-based methods and models suffer from limitations when applied individually to investigate these systems and, therefore, a combined approach is needed. The morphodynamics of coastal environments can be assessed in terms of a mean bed elevation range (BER), which is the difference of the lowest to highest seabed elevation occurring within a defined time interval. In this study of the coastal sector of the German Bight, North Sea, the highly variable distribution of observed BER for the period 1984-2006 is correlated to local bed shear stresses based on hindcast simulations with a well-validated high-resolution (typically 1,000 m in coastal settings) process-based numerical model of the North Sea. A significant correlation of the 95th percentile of bed shear stress and BER was found, explaining between 49 % and 60 % of the observed variance of the BER under realistic forcing conditions. The model then was applied to differentiate the effects of three main hydrodynamic drivers, i.e. tides, wind-induced currents, and waves. Large-scale mapping of these model results quantify previous qualitative suggestions: tides act as main drivers of the East Frisian coast, whereas waves are more relevant for the morphodynamics of the German west coast. Tidal currents are the main driver of the very high morphological activity of the tidal channels of the Ems, Weser and Elbe estuaries, the Jade Bay, and tidal inlets between the islands. This also holds for the backbarrier tidal flats of the North Frisian Wadden Sea. The morphodynamics of the foreshore areas of the barrier island systems are mainly wave-driven; in the deeper areas tides, waves and wind-driven currents have a combined effect. The open tidal flats (outer Ems, Neuwerker Watt, Dithmarschen Bight) are affected by a combination of tides, wind

  9. High Resolution Quaternary Seismic Stratigraphy of the New York Bight Continental Shelf

    USGS Publications Warehouse

    Schwab, William C.; Denny, J.F.; Foster, D.S.; Lotto, L.L.; Allison, M.A.; Uchupi, E.; Swift, B.A.; Danforth, W.W.; Thieler, E.R.; Butman, Bradford

    2003-01-01

    A principal focus for the U.S. Geological Survey (USGS) Coastal and Marine Geology Program (marine.usgs.gov) is regional reconnaissance mapping of inner-continental shelf areas, with initial emphasis on heavily used areas of the sea floor near major population centers. The objectives are to develop a detailed regional synthesis of the sea-floor geology in order to provide information for a wide range of management decisions and to form a basis for further investigations of marine geological processes. In 1995, the USGS, in cooperation with the U.S. Army Corps of Engineers (USACOE), New York District, began to generate reconnaissance maps of the continental shelf seaward of the New York - New Jersey metropolitan area. This mapping encompassed the New York Bight inner-continental shelf, one of the most heavily trafficked and exploited coastal regions in the United States. Contiguous areas of the Hudson Shelf Valley, the largest physiographic feature on this segment of the continental shelf, also were mapped as part of a USGS study of contaminated sediments (Buchholtz ten Brink and others, 1994; 1996). The goal of the reconnaissance mapping was to provide a regional synthesis of the sea-floor geology in the New York Bight area, including: (a) a description of sea-floor morphology; (b) a map of sea-floor sedimentary lithotypes; (c) the geometry and structure of the Cretaceous strata and Quaternary deposits; and (d) the geologic history of the region. Pursuing the course of this mapping effort, we obtained sidescan-sonar images of 100 % of the sea floor in the study area. Initial interpretations of these sidescan data were presented by Schwab and others, (1997a, 1997b, 2000a). High-resolution seismic-reflection profiles collected along each sidescan-sonar line used multiple acoustic sources (e.g., watergun, CHIRP, Geopulse). Multibeam swath-bathymetry data also were obtained for a portion of the study area (Butman and others, 1998;). In this report, we present a series

  10. Development and validation of hydroacoustic monitoring concepts for the coastal German Bight (SE North Sea)

    NASA Astrophysics Data System (ADS)

    Mielck, Finn; Hass, H. Christian; Holler, Peter; Bartholomä, Alexander; Neumann, Andreas; Kröncke, Ingrid; Reimers, Hans-Christian; Capperucci, Ruggero

    2016-04-01

    The joint research project WIMO (Wissenschaftliche Monitoringkonzepte für die Deutsche Bucht/Scientific Monitoring Concepts for the German Bight, NE North Sea) aims at providing methods for detection and analysis of seabed habitats using modern remote sensing techniques. Our subproject focuses on hydroacoustic techniques in order to gain information about seafloor environments and sediment dynamics. In a timeframe of four years, several key areas in the German Bight were repeatedly observed using different hydroacoustic gear (i. e. sidescan sonars, single/multibeam echo sounders and sub-bottom profilers). In order to ground-truth the acoustic data, hundreds of grab samples and underwater videos were taken. With these techniques it is possible to distinguish between different seafloor habitats, which range from muddy to sandy seafloors (esp. near the barrier islands) to rugged or vegetated/populated reefs around Helgoland. The conducted monitoring program revealed seasonal changes regarding the abundance of the sand mason worm (Lanice conchilega) and the brittle star (Amphiora filiformis) as well as ongoing sedimentary processes driven by tidal currents and wind/storms. It was also possible to determine relationships between sediment characteristics and benthos in some key areas. An essential part of our project included a comparison between the datasets obtained with different hydroacoustic devices, configurations, and evaluation methods in the same study areas. The investigation reveals that there could be distinct differences in interpreting the data and hence in the determination of prevailing seafloor habitats, especially in very heterogeneous areas and at transition zones between the habitats. Therefore, it is recommended to employ more than one hydroacoustic system (preferably a singlebeam device combined with a wide-swath sonar system) synchronously during a survey in order to gain more reliable and detailed information about the seafloor environments. The

  11. Distribution of Xantus' Murrelet Synthliboramphus hypoleucus at sea in the Southern California Bight, 1995-97

    USGS Publications Warehouse

    Whitworth, Darrell L.; Takekawa, John Y.; Carter, Harry R.; Newman, Scott H.; Keeney, Thomas W.; Kelly, Paul R.

    2000-01-01

    We radiomarked 153 Xantus' Murrelets Synthliboramphus hypoleucus captured at sea near Santa Barbara Island (SBI), the largest murrelet colony in the California Channel Islands, USA. We tracked these radiomarked murrelets in the Southern California Bight (SCB) off coastal southern California during the 1995-97 breeding seasons. In 1995 during mild El Nino conditions, the murrelets were distributed in non-upwelling areas. In 1996-97, they were distributed in dense patches, aggregating in cool upwelled waters near the northern Channel Islands or south of San Nicolas Island. Murrelets flew longer distances from SBI to foraging areas in 1997 (x?? = 111 ?? 44 km) than in 1996 (x?? = 62 ?? 25 km), but the distances they travelled did not differ between months (Apr and May) within years. Mean foraging distances from SBI were similar for 'incubating' murrelets (determined on the basis of repeated visits to SBI) and 'non-incubating' murrelets during the colony attendance period. We attributed the low return rate of radiomarked murrelets to SBI to the capture and marking of a large proportion of birds that were not actively incubating rather than to any adverse effects of radio attachment. We believe changes in murrelet foraging patterns between the 1970s and 1990s are associated with changes in prey resources in the SCB. Flexibility in the foraging strategies of these murrelets may be related to the highly variable marine environment at the southern end of the California Current Upwelling System.

  12. Food and feeding ecology of purple sandpipers Calidris maritima on rocky intertidal habitats (Helgoland, German Bight)

    NASA Astrophysics Data System (ADS)

    Dierschke, Volker

    On the island of Helgoland (German Bight) Purple Sandpipers Calidris maritima feed mainly in the intertidal of piers and rocky shores. The main prey species are Littorina saxatilis and Mytilus edulis, complemented by crustaceans, polychaetes, other molluscs and green algae. Beach habitats are used as alternative feeding sites during storms. Feeding sites seem to be selected according to rates of assimilated energy intake. The most profitable habitat (wrack beds on the high-tide line with kelp-fly larvae, 16.8 W) is used after arrival in October but is not available during winter. Because of high intake rates in rocky habitats (13.1 W on piers, 5.5 W on mussel beds), which allow short daily feeding times, and available alternative feeding sites during storms, Purple Sandpipers do not need to carry fat reserves in winter like other waders wintering in central and Western Europe. This, and the ever accessible food supply of epibenthic macrofauna on rocky shores, may enable Purple Sandpipers to winter further north than other wader species.

  13. Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Revised

    NASA Technical Reports Server (NTRS)

    Cottrell, Matthew T.; Mannino, Antonio; Kirchman, David L.

    2005-01-01

    The abundance of aerobic anoxygenic phototrophic (AM) bacteria, cyanobacteria and heterotrophs was examined in the Mid-Atlantic Bight and the central North Pacific gyre using infrared fluorescence microscopy coupled with image analysis and flow cytometry. AAP bacteria comprised 5% to 16% of total prokaryotes in the Atlantic but only 5% or less in the Pacific. In the Atlantic, AAP bacterial abundance was as much as 2-fold higher than Prochlorococcus and 10-folder higher than Synechococcus. In contrast, Prochlorococcus outnumbered AAP bacteria 5- to 50-fold in the Pacific. In both oceans, subsurface abundance maxima occurred within the photic zone, and AAP bacteria were least abundant below the 1% light depth. Concentrations of bacteriochlorophyll a (BChl a) were low (approx.1%) compared to chlorophyll a. Although the BChl a content of AAP bacteria per cell was typically 20- to 250-fold lower than the divinyl-chlorophyll a content of Prochlorococcus, in shelf break water the pigment content of AAP bacteria approached that of Prochlorococcus. The abundance of AAP bacteria rivaled some groups of strictly heterotrophic bacteria and was often higher than the abundance of known AAP genera (Erythrobacter and Roseobacter spp.). The distribution of AAP bacteria in the water column, which was similar in the Atlantic and the Pacific, was consistent with phototrophy.

  14. Passive microwave detection of river-plume fronts in the German Bight

    NASA Technical Reports Server (NTRS)

    Blume, H.-J. C.

    1982-01-01

    The NASA P-3 aircraft with the L- and S-band radiometer system on board participated in the MARSEN experiments carried out between August 30 and September 23, 1979. Measurements of surface temperature and salinity were concentrated on freshwater outflows of the Rivers Weser and Elbe in the German Bight. Three missions were carried out, on September 19, 22, and 23. The values of salinity are plotted as a function of geographic position, and contour maps of the salinity distribution are generated from the value plots. It is noted that on September 22, during a noon flood-tide, two river-plume salinity fronts were detected when a body of water with higher salinity existed in front of the Weser delta near Bremerhaven generating with the river outflow of lower saline waters a front of delta-S equals 5 per thousand. Another pocket of lower saline waters was found in front of the Elbe delta at Cuxhaven, which in turn set up a strong front of delta-S equals 6 per thousand. The morning low tide of September 23 did not exhibit this extreme condition.

  15. Toxicity of sediments and interstitial waters form the Southern California Bight

    SciTech Connect

    Bay, S.; Greenstein, D.; Brown, J.; Jirik, A.

    1995-12-31

    The toxicity of 72 sediment samples collected during the EMAP Southern California Bight Pilot Project (SCBPP) was measured. Sediments from the mainland shelf between Point Conception and the Mexican border were collected from various depths and tested for toxicity using two methods. The toxicity of bulk sediment was measured using a 10-day amphipod (Ampelisca abdita) survival test. Interstitial water was also extracted from the samples and tested for toxicity using a 72-hour sea urchin (Strongylocentrotus purpuratus) embryo development test. Amphipod survival was high (> 80%) at all stations tested, although several sites near large sewage outfalls had statistically significant reductions in survival. No interference related to grain size variation was observed with the amphipod test. Most of the interstitial water samples produced abnormal sea urchin embryo development. Effects were not related to the presumed level of sediment contamination, but rather to ammonia concentration in virtually all cases. The impacts of sample handling procedures and ammonia on sediment toxicity data interpretation will be discussed.

  16. A simulation analysis of the fate of phytoplankton within the mid-Atlantic bight

    NASA Technical Reports Server (NTRS)

    Walsh, J. J.; Dieterle, D. A.; Meyers, M. B.

    1986-01-01

    A time-dependent, three-dimensional simulation model of wind-induced changes of the circulation field, of light and nutrient regulation of photosynthesis, of vertical mixing as well as algal sinking, and of herbivore grazing stress, is used to analyze the seasonal production, consumption, and transport of the spring bloom within the mid-Atlantic Bight. The particular case (c) of a 58-day period in February-April 1979, simulated primary production, based on both nitrate and recycled nitrogen, with a mean of 0.62 g C sq m/day over the whole model domain, and an export at the shelf-break off Long Island of 2.60 g ch1 sq m/day within the lower third of the water column. About 57% of the carbon fixation was removed by herbivores, with 21% lost as export, either downshelf or offshore to slope waters, after the first 58 days of the spring bloom. Extension of the model for another 22 days of case (c) increased the mean export to 27%, while variation of the model's parameters in 8 other cases led to a range in export from 8% to 38% of the average primary production. Spatial and temporal variations of the simulated albal biomass, left behind in the shelf water column, reproduced chlorophyll fields sensed by satellite, shipboard, and in situ instruments.

  17. Spatial and temporal patterns of Risso's dolphin echolocation in the Southern California Bight.

    PubMed

    Soldevilla, Melissa S; Wiggins, Sean M; Hildebrand, John A

    2010-01-01

    Geographical and temporal trends in echolocation clicking activity can lead to insights into the foraging and migratory behaviors of pelagic dolphins. Using autonomous acoustic recording packages, the geographical, diel, and seasonal patterns of Risso's dolphin (Grampus griseus) echolocation click activity are described for six locations in the Southern California Bight between 2005 and 2007. Risso's dolphin echolocation click bouts are identified based on their unique spectral characteristics. Click bouts were identified on 739 of 1959 recording days at all 6 sites, with the majority occurring at nearshore sites. A significant diel pattern is evident in which both hourly occurrences of click bouts and click rates are higher at night than during the day. At all nearshore sites, Risso's dolphin clicks were identified year-round, with the highest daily occurrence at the southern end of Santa Catalina Island. Seasonal and interannual variabilities in occurrence were high across sites with peak occurrence in autumn of most years at most sites. These results suggest that Risso's dolphins forage at night and that the southern end of Santa Catalina Island represents an important habitat for Risso's dolphins throughout the year.

  18. Radiocarbon geochronology of the sediments of the São Paulo Bight (southern Brazilian upper margin).

    PubMed

    Mahiques, Michel M; Sousa, Silvia H M; Burone, Leticia; Nagai, Renata H; Silveira, Ilson C A; Figueira, Rubens C L; Soutelino, Rafael G; Ponsoni, Leandro; Klein, Daniel A

    2011-09-01

    The aim of this work was to generate an inventory of the data on radiocarbon datings obtained from sediments of the São Paulo Bight (southern Brazilian upper margin) and to analyze the data in terms of Late Quaternary sedimentary processes and sedimentation rates. A total of 238 radiocarbon datings from materials collected using differents ampling procedures was considered for this work. The sedimentation rates varied from less than 2 to 68 cm.kyr(-1). The highest sedimentation rate values were found in a low-energy (ría type) coastal system as well as in the upwelling zones of Santa Catarina and Cabo Frio. The lowest rates were found on the outer shelf and upper slopes. Our results confirm the strong dependency of the shelf currents, with an emphasis to the terrigenous input from the Río de La Plata outflow which is transported via the Brazilian Coastal Current, as well as of the coupled Brazil Current - Intermediate Western Boundary Current (BC-IWBC) dynamics on the sedimentary processes. At least three indicators of the paleo sea level were found at 12200 yr BP (conventional radiocarbon age) (103 meters below sea level - mbsl), 8300-8800 cal yr BP (13 mbsl) and 7700-8100 cal yr BP (6 mbsl).

  19. Bacterial communities associated with four ctenophore genera from the German Bight (North Sea).

    PubMed

    Hao, Wenjin; Gerdts, Gunnar; Peplies, Jörg; Wichels, Antje

    2015-01-01

    Intense research has been conducted on jellyfish and ctenophores in recent years. They are increasingly recognized as key elements in the marine ecosystem that serve as critical indicators and drivers of ecosystem performance and change. However, the bacterial community associated with ctenophores is still poorly investigated. Based on automated ribosomal intergenic spacer analysis (ARISA) and 16S ribosomal RNA gene amplicon pyrosequencing, we investigated bacterial communities associated with the frequently occurring ctenophore species Mnemiopsis leidyi, Beroe sp., Bolinopsis infundibulum and Pleurobrachia pileus at Helgoland Roads in the German Bight (North Sea). We observed significant differences between the associated bacterial communities of the different ctenophore species based on ARISA patterns. With respect to bacterial taxa, all ctenophore species were dominated by Proteobacteria as revealed by pyrosequencing. Mnemiopsis leidyi and P. pileus mainly harboured Gammaproteobacteria, with Marinomonas as the dominant phylotype of M. leidyi. By contrast, Pseudoalteromonas and Psychrobacter were the most abundant Gammaproteobacteria in P. pileus. Beroe sp. was mainly dominated by Alphaproteobacteria, particularly by the genus Thalassospira. For B. infundibulum, the bacterial community was composed of Alphaproteobacteria and Gammaproteobacteria in equal parts, which consisted of the genera Thalassospira and Marinomonas. In addition, the bacterial communities associated with M. leidyi display a clear variation over time that needs further investigation. Our results indicate that the bacterial communities associated with ctenophores are highly species- specific.

  20. Classification of echolocation clicks from odontocetes in the Southern California Bight.

    PubMed

    Roch, Marie A; Klinck, Holger; Baumann-Pickering, Simone; Mellinger, David K; Qui, Simon; Soldevilla, Melissa S; Hildebrand, John A

    2011-01-01

    This study presents a system for classifying echolocation clicks of six species of odontocetes in the Southern California Bight: Visually confirmed bottlenose dolphins, short- and long-beaked common dolphins, Pacific white-sided dolphins, Risso's dolphins, and presumed Cuvier's beaked whales. Echolocation clicks are represented by cepstral feature vectors that are classified by Gaussian mixture models. A randomized cross-validation experiment is designed to provide conditions similar to those found in a field-deployed system. To prevent matched conditions from inappropriately lowering the error rate, echolocation clicks associated with a single sighting are never split across the training and test data. Sightings are randomly permuted before assignment to folds in the experiment. This allows different combinations of the training and test data to be used while keeping data from each sighting entirely in the training or test set. The system achieves a mean error rate of 22% across 100 randomized three-fold cross-validation experiments. Four of the six species had mean error rates lower than the overall mean, with the presumed Cuvier's beaked whale clicks showing the best performance (<2% error rate). Long-beaked common and bottlenose dolphins proved the most difficult to classify, with mean error rates of 53% and 68%, respectively.

  1. Invertebrate communities associated with hard bottom habitats in the South Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Wenner, E. L.; Knott, D. M.; Van Dolah, R. F.; Burrell, V. G.

    1983-08-01

    Epibenthic invertebrates associated with nine hard bottom areas in the South Atlantic Bight between South Carolina and northern Florida were collected with dredge, trawl, suction and grab samplers to evaluate species composition, biomass, abundance, diversity, spatial distributions, and seasonality (winter and summer). Species composition changed noticeably with depth and season. Inner and outer shelf stations were least similar in species composition. Middle shelf areas were transitional and contained taxa characteristic of both inner and outer sites. Bryozoa (88 taxa), Cnidaria (85 taxa), Porifera (67 taxa), Annelida (261 taxa) and Mollusca (203 taxa) represented the richest taxonomic groups of the 1175 taxa collected. Both diversity (1175 total taxa) and biomass (1995 kg total) of invertebrates from hard bottom areas exceeded those reported in the literature for sand bottom communities. Sponges accounted for >60% of the total invertebrate biomass collected by dredge and trawl during both seasons. High diversity values were attributed primarily to habitat complexity and did not exhibit any discernible pattern with depth or latitude.

  2. Development of a Shelf-Wide Ocean Observatory in the Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Schofield, O.; Glenn, S.; Haidvogel, D.; Moline, M.; Bissett, P. W.

    2001-12-01

    Currently a shelf-wide ocean observatory is being constructed to characterize the physical forcing of continental shelf primary productivity in the New York Bight (NYB). This proposal will expand the existing 30 x 30 km research space of the existing Lon-term Ecosystem Observatory (LEO) coastal ocean observatory to 300 x 300 km in order to characterize relevant spatial and temporal biogeochemical scales. The shelf observatory will consist of (1) long-range CODAR surface currents, (2) the international constellation of ocean color satellites, (3) physical/bio-optical cabled observatories, and (4) subsurface autonomonous underwater vehicles. Operation of the observatory will be through a centralized computer network dedicated to receiving, processing and visualizing the real-time data and disseminating results to both field scientists and ocean forecasters over the World Wide Web. The observation data-stream is assimilated into the new generation ocean forecast models providing a means to adaptively sample episodic events on the shlef. All components of the observatory were tested during the ONR-Sponsored HyCODE/COMOP Coastal Predictive Skill Experiments during the summer of 2000 and 2001. The shelf-wide system will be a central component of the NorthEast Observatory System (NEOS), which is a consortium of the major academic oceanographic institutions from Virginia to Maine.

  3. Near-bottom currents over the continental slope in the Mid-Atlantic Bight

    USGS Publications Warehouse

    Csanady, G.T.; Churchill, J.H.; Butman, B.

    1988-01-01

    From a set of 28 current meter records we have found that near-bottom currents faster than 0.2 m s-1 occur frequently over the outer continental shelf of the Mid-Atlantic Bight (bottom depth <210 m) but very rarely (<1% of the time) between bottom depths of 500 m and 2 km over the slope. The rarity of strong near-bottom flow over the middle and lower slope allows the accumulation of fine-grained sediment and organic carbon in this region. Fast near-bottom currents which do occur over the slope are invariably associated with topographic waves, although it is often superimposed inertial oscillations which increase current speed above the level of 0.2 m s-1. Episodes of intense inertial oscillations occur randomly and last typically for 10-20 days. Their energy source is unknown. Topographic wave energy exhibits a slight, but statistically significant, minimum over the mid-slope. These waves appear irregularly and vary both along isobaths and in time. The irregularity is presumably a consequence of random topographic wave generation by Gulf Stream instability. The current regime within sea-floor depressions in the slope (canyons and gullies) is distinctly different from that of the open slope; most notable is the near absence of topographic wave motion within depressions. ?? 1988.

  4. Satellite detection of phytoplankton export from the mid-Atlantic Bight during the 1979 spring bloom

    NASA Technical Reports Server (NTRS)

    Walsh, J. J.; Dieterle, D. A.; Esaias, W. E.

    1986-01-01

    Analysis of Coastal Zone Color Scanner (CZCS) imagery confirms shipboard and in situ moored fluorometer observations of resuspension of near-bottom chlorophyll within surface waters (1 to 10 m) by northwesterly wind events in the mid-Atlantic Bight. As much as 8 to 16 micrograms chl/l are found during these wind events from March to May, with a seasonal increase of algal biomass until onset of stratification of the water column. Rapid sinking or downwelling apparently occurs after subsequent wind events, however, such that the predominant surface chlorophyll pattern is approx. 0.5 to 1.5 micrograms/l over the continental shelf during most of the spring bloom. Perhaps half of the chlorophyll increase observed by satellite during a wind resuspension event represents in-situ production during the 4 to 5 day interval, with the remainder attributed to accumulation of algal biomass previously produced and temporarily stored within near-bottom water. Present calculations suggest that about 10% of the primary production of the spring bloom may be exported as ungrazed phytoplankton carbon from mid-Atlantic shelf waters to those of the continental slope.

  5. Variability in along-shelf and cross-shelf circulation in the South Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Yuan, Yeping; Castelao, Renato M.; He, Ruoying

    2017-02-01

    Variability in along-shelf and cross-shelf circulation in the South Atlantic Bight (SAB) is investigated using altimetry observations. Satellite-derived along-shelf velocity anomalies are in good agreement with independent near-surface current measurements from moored acoustic Doppler current profilers and surface velocities from high frequency radar at adjacent locations. This is especially true if wind-driven Ekman velocities are added to the geostrophic velocities, suggesting that the influence of Ekman dynamics to surface along-shelf flow in the SAB is unusually large. The decade-long time series reveals substantial seasonal variability in surface velocities, with peak poleward anomalies during late spring and summer and strong equatorward flow during autumn. Convergences and divergences in the along-shelf transport between two cross-sections are compared with three-dimensional numerical model results and used to estimate cross-shelf transport across the 50 m isobath in the SAB. The calculation suggests a pattern of weak offshore flow during spring followed by prolonged and relatively stronger offshore flow during summer and early autumn, while cross-shelf velocity anomalies during winter are weak and slightly onshore. Prolonged offshore flow following the peak in river discharge that generally occurs in spring indicates the potential for the establishment of a conduit for offshore export of riverine material. The long-term time series also reveals several large events of interannual variability, including the 2003 cold event observed in the SAB.

  6. Biological processes in the water column of the South Atlantic Bight: Phytoplankton response. Final progress report

    SciTech Connect

    Verity, P.G.; Yoder, J.A.

    1992-03-10

    This study addressed shelf-wide processes and nearshore (coastal boundary zone) processes occurring in the southeastern. Coastal boundary zone (CBZ) US continental shelf dynamics involve studies of circulation and of biological and chemical transformations. Continental shelf processes affect the removal of material from the coastal boundary zone into areas where the material no longer interacts with or influences concentrations in the CBZ. The two arbitrarily separate components are, in fact, unified. The CBZ typically extends about 300 km along-shore and about 20 km offshore from its center off Savannah, Georgia, where most runoff occurs. The rates of biological and chemical transformations are controlled by proximity to the bottom and the amounts of fine suspended organic matter originating from rivers and salt marshes. Once material is removed from this zone, either by a long-shelf or cross-shelf advection to regions where the materials are no longer in contact with the bottom, the suite of factors governing the rates of chemical and biological transformations changes. The determination of contrasting rates in these two environments was one of the central focuses of the South Atlantic Bight program.

  7. Kinematics and planktonic ecosystem dynamics of a coastal cyclonic eddy in the Southern California Bight

    NASA Astrophysics Data System (ADS)

    Chenillat, F.; Franks, P. J. S.; Riviere, P.; Capet, X.; Blanke, B.

    2014-12-01

    The highly productive Californian eastern boundary upwelling system exhibits high mesoscale eddy activity. Eddies that are formed at the coast move offshore, entraining and redistributing nearshore nutrients and planktonic organisms. High planktonic biomass can be found in these eddies months after detaching from the coast. The mechanisms driving these patterns, and their ecological impacts are still poorly understood. To characterize and understand the influence of mesoscale eddies on planktonic ecosystems in the California Current System (CCS) we use a numerical approach coupling the Regional Ocean Modeling system (ROMS), at 5 km horizontal resolution, with a multiple size class planktonic ecosystem model (NEMURO). Combining Eulerian and Lagrangian analyses, we were able to follow one specific cyclonic eddy formed in the Southern California Bight as it detached from the coast and migrated offshore. Lagrangian particle tracking allowed us to identify the eddy core where high concentrations of coastal nutrients are found. The Eulerian calculations allowed us to quantify ecosystem properties and dynamics along the particle tracks. We highlight the role of this eddy in altering local planktonic ecosystem dynamics, and contrast those dynamics with the coastal upwelling source waters, and the waters encircling the eddy.

  8. Parasite transfer from crustacean to fish hosts in the Lübeck Bight, SW Baltic Sea

    NASA Astrophysics Data System (ADS)

    Zander, C. D.; Groenewold, S.; Strohbach, U.

    1994-03-01

    Four helminth parasites out of 19 species found in the Lübeck Bight, Baltic Sea, were chosen for investigations on the transfer from invertebrate to small-sized fish hosts: larvae of the tapeworms Schistocephalus sp. and Bothriocephalus sp. (Cestoda) living in planktonic copepods as primary hosts; Podocotyle atomon (Digenea) and Hysterothylacium sp. (Nematoda) were found in benthic crustaceans, especially Gammarus spp. These hosts were the prey of 3 gobiid fishes, Gobiusculus flavescens (feeding mainly on plankton), Pomatoschistus minutus (preferring benthos), and P. pictus (feeding more on plankton than benthos). Because the fishes selected smaller sizes of crustaceans, they ingested all stages of the copepods but only the smaller-sized groups of gammarids which were often less infested by parasites. In order to evaluate the probability for a fish to be parasitized by a helminth, an infestation potential index (IP) was calculated. Podocotyle atomon and Hysterothylacium sp. revealed an IP which was far lower in gobies than expected when the prevalences of the previous hosts were taken into consideration. The IP of tapeworm larvae was mainly influenced by the feeding pressure of the gobiid predators, which might change with developmental stage and season. It is concluded that parasite transfer to the next host decreases when sizes of prey and predator differ only moderately. This mechanism can reduce the numbers of parasites transferred to less suitable or wrong hosts.

  9. Resolution of fine biological structure including small narcomedusae across a front in the Southern California Bight

    NASA Astrophysics Data System (ADS)

    McClatchie, Sam; Cowen, Robert; Nieto, Karen; Greer, Adam; Luo, Jessica Y.; Guigand, Cedric; Demer, David; Griffith, David; Rudnick, Daniel

    2012-04-01

    We sampled a front detected by SST gradient, ocean color imagery, and a Spray glider south of San Nicolas Island in the Southern California Bight between 14 and 18 October 2010. We sampled the front with an unusually extensive array of instrumentation, including the Continuous Underway Fish Egg Sampler (CUFES), the undulating In Situ Ichthyoplankton Imaging System (ISIIS) (fitted with temperature, salinity, oxygen, and fluorescence sensors), multifrequency acoustics, a surface pelagic trawl, a bongo net, and a neuston net. We found higher fluorescence and greater cladoceran, decapod, and euphausiid densities in the front, indicating increased primary and secondary production. Mesopelagic fish were most abundant in oceanic waters to the west of the front, market squid were abundant in the front associated with higher krill and decapod densities, and jack mackerel were most common in the front and on the shoreward side of the front. Egg densities peaked to either side of the front, consistent with both offshore (for oceanic squid and mesopelagic fish) and shelf origins (for white croaker and California halibut). We discovered unusually high concentrations of predatory narcomedusae in the surface layer of the frontal zone. Potential ichthyoplankton predators were more abundant either in the front (decapods, euphausiids, and squid) or shoreward of the front (medusae, chaetognaths, and jack mackerel). For pelagic fish like sardine, which can thrive in less productive waters, the safest place to spawn would be offshore because there are fewer potential predators.

  10. Studies of a wind mechanism influencing the recruitment of blue crabs in the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Johnson, Donald R.; Hester, Betty S.; McConaugha, John R.

    This report forms part of an on-going effort to understand the large yearly variations in blue crab harvest of Chesapeake Bay. Recent sampling programs have indicated that the larvae are transported out of the bay immediately after being spawned, and spend their first month offshore at the sea surface. Although it is well established that a mid and outer shelf southward flow occurs during all seasons in the Middle Atlantic Bight, very little is known of the nearshore currents. This study constitutes an effort to determine if the characteristically light, but northward, wind stress during the critical summer months is sufficient to drive northward counter flow at the surface and, hence, to reduce the chances that the larvae are being advected south and lost from the area of Chesapeake Bay. We investigate a local model of wind-driven currents on the continental shelf with vertical decoupling at the pycnocline. Additional driving forces include an alongshore sea surface slope and horizontal pressure gradients. With characteristic forcing values, it is found that the wind stress is indeed sufficient to drive a light northward flow within 25 to 50 km of the shoreline. We expect, then, that blue crab larval recruitment back to Chesapeake Bay may be partially dependent on summer wind stress. A comparison between a wind index time series and harvest several years later is strongly suggestive of such a dependency.

  11. Seafloor habitat mapping of the New York Bight incorporating sidescan sonar data

    USGS Publications Warehouse

    Lathrop, R.G.; Cole, M.; Senyk, N.; Butman, B.

    2006-01-01

    The efficacy of using sidescan sonar imagery, image classification algorithms and geographic information system (GIS) techniques to characterize the seafloor bottom of the New York Bight were assessed. The resulting seafloor bottom type map was compared with fish trawl survey data to determine whether there were any discernable habitat associations. An unsupervised classification with 20 spectral classes was produced using the sidescan sonar imagery, bathymetry and secondarily derived spatial heterogeneity to characterize homogenous regions within the study area. The spectral classes, geologic interpretations of the study region, bathymetry and a bottom landform index were used to produce a seafloor bottom type map of 9 different bottom types. Examination of sediment sample data by bottom type indicated that each bottom type class had a distinct composition of sediments. Analysis of adult summer flounder, Paralichthys dentatus, and adult silver hake, Merluccius bilinearis, presence/absence data from trawl surveys did not show evidence of strong associations between the species distributions and seafloor bottom type. However, the absence of strong habitat associations may be more attributable to the coarse scale and geographic uncertainty of the trawl sampling data than conclusive evidence that no habitat associations exist for these two species. ?? 2006 Elsevier Ltd. All rights reserved.

  12. Simulation of the 1979 spring bloom in the Mid-Atlantic Bight - A coupled physical/biological/optical model

    NASA Technical Reports Server (NTRS)

    Gregg, Watson W.; Walsh, John J.

    1992-01-01

    A coupled physical/biological/optical model is developed for studies of phytoplankton variability in the spring 1979 Mid-Atlantic Bight, as observed by CZCS imagery. The model incorporates advection, mixing, sinking, growth as a function of light, temperature, nutrient availability, and death as a function of ingestion. It produced chlorophyll concentrations within the first attenuated depth within 1 standard deviation of CZCS imagery on large scale. The primary production estimates obtained using this model were within reasonable agreement with those measured in situ.

  13. Analysis of the upscaling problem - A case study for the barotropic dynamics in the North Sea and the German Bight

    NASA Astrophysics Data System (ADS)

    Schulz-Stellenfleth, J.; Stanev, E. V.

    2016-04-01

    The upscaling problem is investigated using the barotropic dynamics of the North Sea and the German Bight as an example. The impact of small scale perturbations of bathymetry, bottom roughness, wind forcing, and boundary forcing is quantified using a two-dimensional linear barotropic model for the entire North Sea with 5 km resolution. The model is solved in the spectral domain for the dominant M2 tide. Comparisons with results from a fully nonlinear 3D circulation model show that the main circulation features are well captured by the spectral model. The impact of different types of perturbations is estimated by inversion of the model using the perturbation covariance matrix as input. Case studies with white noise and fully correlated noise are presented. It is shown that the German Bight area stands out in its sensitivity with respect to small scale uncertainties of bathymetry. Small scale changes of bottom roughness have a particularly strong effect in the English Channel. Small scale wind perturbations have a significant local effect only in very shallow near coastal areas. It is shown that uncorrelated noise introduced along an open boundary around the German Bight only has a very local effect. Perturbations with long correlation length are shown to lead to significant far field effects along the east coast of England. It is demonstrated that this effect is related to the boundary conditions used for the North Sea model. In a next step a German Bight grid with 1 km resolution is nested into the North Sea grid and the spectral model is solved in a two way nested configuration. It is shown that there are some significant local and far field effects caused by the change of resolution in this coastal area. Finally, the potential impact of observations taken in coastal areas is investigated by evaluating the Kalman a posteriori distribution of analysis vectors based on different assumptions about model errors. The area of influence of a single tide gauge is

  14. National Aeronautics and Space Administration operations: Remote sensing experiments in the New York Bight, 7-17 April 1975

    NASA Technical Reports Server (NTRS)

    Usry, J. W.; Hall, J. B., Jr.

    1975-01-01

    Results are given of remote sensing experiments conducted in the New York Bight between April 7-17, 1975, to evaluate the role of remote sensing technology to aid in monitoring ocean dumping. Remote sensors were flown on the C-54, U-2, and C-130 aircraft while the National Oceanic and Atmospheric Administration obtained concurrent in situ sea truth data using helicopters and surface platforms. The test site, aircraft platforms, experiments, and supporting sensors are described. The operation of each aircraft are discussed and aircraft flight lines, flight parameters, and data identification parameters are presented in figures and tables.

  15. Pico and nanoplankton abundance and carbon stocks along the Brazilian Bight.

    PubMed

    Gérikas Ribeiro, Catherine; Lopes Dos Santos, Adriana; Marie, Dominique; Helena Pellizari, Vivian; Pereira Brandini, Frederico; Vaulot, Daniel

    2016-01-01

    Pico and nanoplankton communities from the Southwest Atlantic Ocean along the Brazilian Bight are poorly described. The hydrography in this region is dominated by a complex system of layered water masses, which includes the warm and oligotrophic Tropical Water (TW), the cold and nutrient rich South Atlantic Central Water (SACW) and the Coastal Water (CW), which have highly variable properties. In order to assess how pico- and nanoplankton communities are distributed in these different water masses, we determined by flow cytometry the abundance of heterotrophic bacteria, Prochlorococcus, Synechococcus and autotrophic pico and nanoeukaryotes along three transects, extending from 23°S to 31°S and 39°W to 49°W. Heterotrophic bacteria (including archaea, maximum of 1.5 × 10(6) cells mL(-1)) were most abundant in Coastal and Tropical Water whereas Prochlorococcus was most abundant in open-ocean oligotrophic waters (maximum of 300 × 10(3) cells mL(-1)). Synechococcus(up to 81 × 10(3) cells mL(-1)), as well as autotrophic pico and nanoeukaryotes seemed to benefit from the influx of nutrient-rich waters near the continental slope. Autotrophic pico and nanoeukaryotes were also abundant in deep chlorophyll maximum (DCM) layers from offshore waters, and their highest abundances were 20 × 10(3) cells mL(-1) and 5 × 10(3) cells mL(-1), respectively. These data are consistent with previous observations in other marine areas where Synechococcus and autotrophic eukaryotes dominate mesotrophic waters, whereas Prochlorococcus dominate in more oligotrophic areas. Regardless of the microbial community structure near the surface, the carbon stock dominance by autotrophic picoeukaryotes near the DCM is possibly linked to vertical mixing of oligotrophic surface waters with the nutrient-rich SACW and their tolerance to lower light levels.

  16. Pico and nanoplankton abundance and carbon stocks along the Brazilian Bight

    PubMed Central

    Lopes dos Santos, Adriana; Marie, Dominique; Helena Pellizari, Vivian; Pereira Brandini, Frederico; Vaulot, Daniel

    2016-01-01

    Pico and nanoplankton communities from the Southwest Atlantic Ocean along the Brazilian Bight are poorly described. The hydrography in this region is dominated by a complex system of layered water masses, which includes the warm and oligotrophic Tropical Water (TW), the cold and nutrient rich South Atlantic Central Water (SACW) and the Coastal Water (CW), which have highly variable properties. In order to assess how pico- and nanoplankton communities are distributed in these different water masses, we determined by flow cytometry the abundance of heterotrophic bacteria, Prochlorococcus, Synechococcus and autotrophic pico and nanoeukaryotes along three transects, extending from 23°S to 31°S and 39°W to 49°W. Heterotrophic bacteria (including archaea, maximum of 1.5 × 106 cells mL−1) were most abundant in Coastal and Tropical Water whereas Prochlorococcus was most abundant in open-ocean oligotrophic waters (maximum of 300 × 103 cells mL−1). Synechococcus(up to 81 × 103 cells mL−1), as well as autotrophic pico and nanoeukaryotes seemed to benefit from the influx of nutrient-rich waters near the continental slope. Autotrophic pico and nanoeukaryotes were also abundant in deep chlorophyll maximum (DCM) layers from offshore waters, and their highest abundances were 20 × 103 cells mL−1 and 5 × 103 cells mL−1, respectively. These data are consistent with previous observations in other marine areas where Synechococcus and autotrophic eukaryotes dominate mesotrophic waters, whereas Prochlorococcus dominate in more oligotrophic areas. Regardless of the microbial community structure near the surface, the carbon stock dominance by autotrophic picoeukaryotes near the DCM is possibly linked to vertical mixing of oligotrophic surface waters with the nutrient-rich SACW and their tolerance to lower light levels. PMID:27867760

  17. Internal-tide interactions with the Gulf Stream and Middle Atlantic Bight shelfbreak front

    NASA Astrophysics Data System (ADS)

    Kelly, Samuel M.; Lermusiaux, Pierre F. J.

    2016-08-01

    Internal tides in the Middle Atlantic Bight region are found to be noticeably influenced by the presence of the shelfbreak front and the Gulf Stream, using a combination of observations, equations, and data-driven model simulations. To identify the dominant interactions of these waves with subtidal flows, vertical-mode momentum and energy partial differential equations are derived for small-amplitude waves in a horizontally and vertically sheared mean flow and in a horizontally and vertically variable density field. First, the energy balances are examined in idealized simulations with mode-1 internal tides propagating across and along the Gulf Stream. Next, the fully nonlinear dynamics of regional tide-mean-flow interactions are simulated with a primitive-equation model, which incorporates realistic summer-mesoscale features and atmospheric forcing. The shelfbreak front, which has horizontally variable stratification, decreases topographic internal-tide generation by about 10% and alters the wavelengths and arrival times of locally generated mode-1 internal tides on the shelf and in the abyss. The (sub)mesoscale variability at the front and on the shelf, as well as the summer stratification itself, also alter internal-tide propagation. The Gulf Stream produces anomalous regions of O(20 mW m-2) mode-1 internal-tide energy-flux divergence, which are explained by tide-mean-flow terms in the mode-1 energy balance. Advection explains most tide-mean-flow interaction, suggesting that geometric wave theory explains mode-1 reflection and refraction at the Gulf Stream. Geometric theory predicts that offshore-propagating mode-1 internal tides that strike the Gulf Stream at oblique angles (more than thirty degrees from normal) are reflected back to the coastal ocean, preventing their radiation into the central North Atlantic.

  18. Diet composition and resource partitioning in two small flatfish species in the German Bight

    NASA Astrophysics Data System (ADS)

    Schückel, S.; Sell, A.; Kröncke, I.; Reiss, H.

    2011-10-01

    Since the late 1980s, the small-sized non-commercial flatfish species solenette ( Buglossidium luteum) and scaldfish ( Arnoglossus laterna) have increased in abundance in the southern North Sea. Because these species are considered as possible competitors for prey of commercial flatfish, this study aimed at advancing knowledge of their feeding ecology. Between January 2009 and January 2010 stomach contents of solenette and scaldfish and benthic infauna were sampled seasonally in a study area in the German Bight. The objectives were to investigate the seasonal variability of feeding activity and diet composition of both flatfish species related to benthic prey availability. For both flatfish, the highest feeding activity was found in summer, at the same time that the highest prey densities occurred in the study area. A reduced feeding activity was observed during the winter of 2010, but not in the winter of 2009, probably related to higher 2009 water temperatures. In all seasons, diet composition of solenette was dominated by meiofauna, mainly harpacticoid copepods. Macrofauna prey species, namely juveniles of bivalves and echinoderms became important in spring. An increase in amphipods and cumaceans was found in the stomach contents during summer and autumn, simultaneously with their increased abundance in the benthic infauna. In contrast, polychaetes were rarely found in the diet, but dominated the infauna during all seasons. Diet composition of scaldfish was dominated by larger and mobile prey, and, during all seasons, was mainly comprised of crustaceans. Amphipods characterised the diet in both winters, while decapods such as Crangon spp. and Liocarcinus spp. were the dominant prey from spring to autumn. Additionally, juveniles of flatfish (Pleuronectids) and bivalves were found in the scaldfish diet in spring, replaced by cumaceans in summer. No dietary overlap between both flatfish species was found across seasons, indicating partitioning of prey resources

  19. Simulation of Water Age and Residence Time in the New York Bight

    NASA Astrophysics Data System (ADS)

    Zhang, W. G.; Wilkin, J. L.; Schofield, O. M.

    2008-12-01

    Aiming at investigating the time scale of transporting biogeochemical tracers in the New York Bight (NYB), this work looks into the time scale associated with freshwater propagation in NYB. The Constituent-oriented Age and Residence-time Theory is applied in Regional Ocean Modeling System and then verified. Three-year mean age and two-year mean residence time simulations are carried out. Comparison between snapshots of modeled surface freshwater mean age and satellite measured channel ratio, an empirical proxy of age, shows agreement on the general patterns. Least square fit gives the first order estimation of the relationship between channel ratio and mean age. Time series show temporal and spatial variation in mean age, and seasonal averages demonstrate seasonality of surface mean age consistent with surface circulation. Correlation between surface mean age and wind shows major effects wind in different directions has on mean age. Time series of the mean residence time exhibits strong temporal fluctuation in the scale of days, and seasonal averages show seasonality in surface mean residence time, too. The surprising high value of mean residence time along the Long Island coast in spring and summer is caused by the reentry of previously exited water from the eastern boundary after wind changes direction. Correlation between mean residence time and wind shows major effects wind has on the time freshwater and tracers spend in the New York apex area. Results obtained here are very useful for coastal management and studies of local biogeochemical processes and larval dispersal given the ecological and economical importance of the New York Bay.

  20. Environmental factors affecting methane distribution and bacterial methane oxidation in the German Bight (North Sea)

    NASA Astrophysics Data System (ADS)

    Osudar, Roman; Matoušů, Anna; Alawi, Mashal; Wagner, Dirk; Bussmann, Ingeborg

    2015-07-01

    River estuaries are responsible for high rates of methane emissions to the atmosphere. The complexity and diversity of estuaries require detailed investigation of methane sources and sinks, as well as of their spatial and seasonal variations. The Elbe river estuary and the adjacent North Sea were chosen as the study site for this survey, which was conducted from October 2010 to June 2012. Using gas chromatography and radiotracer techniques, we measured methane concentrations and methane oxidation (MOX) rates along a 60 km long transect from Cuxhaven to Helgoland. Methane distribution was influenced by input from the methane-rich mouth of the Elbe and gradual dilution by methane-depleted sea water. Methane concentrations near the coast were on average 30 ± 13 nmol L-1, while in the open sea, they were 14 ± 6 nmol L-1. Interestingly, the highest methane concentrations were repeatedly detected near Cuxhaven, not in the Elbe River freshwater end-member as previously reported. Though, we did not find clear seasonality we observed temporal methane variations, which depended on temperature and presumably on water discharge from the Elbe River. The highest MOX rates generally coincided with the highest methane concentrations, and varied from 2.6 ± 2.7 near the coast to 0.417 ± 0.529 nmol L-1 d-1 in the open sea. Turnover times varied from 3 to >1000 days. MOX rates were strongly affected by methane concentration, temperature and salinity. We ruled out the supposition that MOX is not an important methane sink in most of the Elbe estuary and adjacent German Bight.

  1. The epizoic diatom community on four bryozoan species from Helgoland (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Wuchter, Cornelia; Marquardt, Jürgen; Krumbein, Wolfgang

    2002-09-01

    The composition of the diatom community on the bryozoans Electra pilosa, Membranipora membranacea, Flustra foliacea, and Alcyonidium gelatinosum from the German Bight was studied by light and scanning electron microscopy. In total, members of 26 diatom genera were found, with Cocconeis, Tabularia, Licmophora, Amphora, and Navicula being the most abundant. The amount and the composition of the diatom covering seem to be typical for single bryozoan species. Electra pilosa and Membranipora membranacea showed a rather dense covering with 71-547 cells/mm2 and 77-110 cells/mm2, respectively. The most prominent genus on Electra pilosa was Cocconeis, reaching up to 58% of all diatoms in one sample, followed by Navicula, Tabularia and Amphora. The most abundant genera on Membranipora membranacea were Tabularia and Licmophora, making up almost 70% of all diatoms in one sample, followed by Navicula, Cocconeis and Amphora. The diatom composition was very stable on all Electra samples, but varied on Membranipora samples. With <1-27 cells/mm2, diatoms were much less abundant on Alcyonidium gelatinosum. Members of the genera Tabularia and Navicula were the most frequently found benthic diatoms, whereas the planktonic forms Coscinodiscus, Cyclotella, and Thalassiosira made up 35% of the diatoms. On Flustra foliacea, diatoms were virtually absent, with fewer than 5 cells/mm2. The low diatom numbers are probably due to toxic metabolites produced by the host. The same may be true for Alcyonidium gelatinosum, but here they might also be a consequence of the surface properties of the bryozoan.

  2. The epizoic diatom community on four bryozoan species from Helgoland (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Wuchter, Cornelia; Marquardt, Jürgen; Krumbein, Wolfgang E.

    2003-03-01

    The composition of the diatom community on the bryozoans Electra pilosa, Membranipora membranacea, Flustra foliacea, and Alcyonidium gelatinosum from the German Bight was studied by light and scanning electron microscopy. In total, members of 26 diatom genera were found, with Cocconeis, Tabularia, Licmophora, Amphora, and Navicula being the most abundant. The amount and the composition of the diatom covering seem to be typical for single bryozoan species. Electra pilosa and Membranipora membranacea showed a rather dense covering with 71-547 cells/mm2 and 77-110 cells/mm2, respectively. The most prominent genus on Electra pilosa was Cocconeis, reaching up to 58% of all diatoms in one sample, followed by Navicula, Tabularia and Amphora. The most abundant genera on Membranipora membranacea were Tabularia and Licmophora, making up almost 70% of all diatoms in one sample, followed by Navicula, Cocconeis and Amphora. The diatom composition was very stable on all Electra samples, but varied on Membranipora samples. With <1-27 cells/mm2, diatoms were much less abundant on Alcyonidium gelatinosum. Members of the genera Tabularia and Navicula were the most frequently found benthic diatoms, whereas the planktonic forms Coscinodiscus, Cyclotella, and Thalassiosira made up 35% of the diatoms. On Flustra foliacea, diatoms were virtually absent, with fewer than 5 cells/mm2. The low diatom numbers are probably due to toxic metabolites produced by the host . The same may be true for Alcyonidium gelatinosum, but here they might also be a consequence of the surface properties of the bryozoan.

  3. Improving current forecasts for the German Bight using HF radar measurements

    NASA Astrophysics Data System (ADS)

    Schulz-Stellenfleth, Johannes; Stanev, Emil; Staneva, Joanna

    2015-04-01

    Three HF radar stations located at the islands of Wangerooge and Sylt as well as on the mainland in Büsum are operated in the German Bight as part of COSYNA system. The WERA system operates at 12.4 MHz and provides surface current measurements every 20 min. The observations are merged with numerical model data to optimise state estimates on a pre-operational basis. The presentation introduces the spatio temporal interpolation (STOI) method, which is a statistical approach to correct data from a free model run using an analysis window of typically one tidal cycle. The technique is thus able to resolve intra-tidal time scales. The scheme is based on an EOF analysis to estimate the model error background statistics and is capable of providing improved short term forecasts. Statistics of the free model run, the HF radar data and the STOI analysis are shown for several month. Both the three dimensional primitive equation model GETM and the operational BSH model are used to provide free model run data. GETM setups with boundary forcing from the MYOCEAN North West Shelf model are used. Maps of innovation and residuals are presented. Furthermore forecast errors for different forecast horizons are discussed. Results are also compared to independent measurements taken at the FINO-1 and FINO-2 platforms. The impact of the analysis is, e.g., illustrated by drifter trajectory simulations. First results are also shown regarding an extension of the STOI method, which includes a model restart to further improve the dynamical consistency of the results. Issues related to the treatment of the boundary forcing and the meteo forcing used during the forecast period are discussed. The impact of the HF radar data on water level estimates are analysed. Furthermore, some results concerning the potential impact of existing and hypothetical HF radar systems are presented, which were obtained making use of the STOI method as well as statistical OSE and OSSE techniques.

  4. Ocean forecasting for the German Bight: from regional to coastal scales

    NASA Astrophysics Data System (ADS)

    Stanev, Emil V.; Schulz-Stellenfleth, Johannes; Staneva, Joanna; Grayek, Sebastian; Grashorn, Sebastian; Behrens, Arno; Koch, Wolfgang; Pein, Johannes

    2016-10-01

    This paper describes recent developments based on advances in coastal ocean forecasting in the fields of numerical modeling, data assimilation, and observational array design, exemplified by the Coastal Observing System for the North and Arctic Seas (COSYNA). The region of interest is the North and Baltic seas, and most of the coastal examples are for the German Bight. Several pre-operational applications are presented to demonstrate the outcome of using the best available science in coastal ocean predictions. The applications address the nonlinear behavior of the coastal ocean, which for the studied region is manifested by the tidal distortion and generation of shallow-water tides. Led by the motivation to maximize the benefits of the observations, this study focuses on the integration of observations and modeling using advanced statistical methods. Coastal and regional ocean forecasting systems do not operate in isolation but are linked, either weakly by using forcing data or interactively using two-way nesting or unstructured-grid models. Therefore, the problems of downscaling and upscaling are addressed, along with a discussion of the potential influence of the information from coastal observatories or coastal forecasting systems on the regional models. One example of coupling coarse-resolution regional models with a fine-resolution model interface in the area of straits connecting the North and Baltic seas using a two-way nesting method is presented. Illustrations from the assimilation of remote sensing, in situ and high-frequency (HF) radar data, the prediction of wind waves and storm surges, and possible applications to search and rescue operations are also presented. Concepts for seamless approaches to link coastal and regional forecasting systems are exemplified by the application of an unstructured-grid model for the Ems Estuary.

  5. Dissolved methane concentration and flux in the coastal zone of the Southern California Bight-Mexican sector: Possible influence of wastewater

    EPA Science Inventory

    We measured dissolved methane concentrations ([CH4]) in the coastal zone of the Southern California Bight-Mexican sector (SCBMex) during two cruises: S1 in the USA–Mexico Border Area (BA) during a short rainstorm and S2 in the entire SCBMex during a drier period a few days later....

  6. A study of sediment motion and bottom boundary layer dynamics over the Middle Atlantic Bight shelf and upper slope. Final report

    SciTech Connect

    Churchill, James H.; Williams, Albert J.

    2001-02-14

    This report summarizes research on circulation and particle dynamics over the Middle Atlantic Bight shelf and upper slope. It includes an overview of the field experiments conducted in the waters off North Carolina, and gives the principal results from these experiments.

  7. Remineralization of particulate authigenic trace metals in the middle Atlantic Bight: Implications for proxies of export production

    NASA Astrophysics Data System (ADS)

    Kumar, N.; Anderson, R. F.; Biscaye, P. E.

    1996-09-01

    Samples collected by time-series sediment traps deployed in the Middle Atlantic Bight were studied to better understand the formation, and preservation, of particulate authigenic forms of trace metals (Cu, Ni, Ba) That hold potential to serve as proxies in the sedimentary record of past changes in the flux of biogenic detritus sinking from the surface ocean into the deep sea (export production). Particulate biogenic and authigenic phases are extremely labile, as evidenced by the observation that as much as 70% of the particulate fluxes of organic carbon and of certain metals (Cu, Ni, and Mn), and up to 25% of the particulate fluxes of authigenic Ba and of opal collected by sediment traps are released rapidly into solution during the time period between particle collection and trap retrieval. Further remineralization on the seabed reduces concentrations of authigenic Cu and Ni in surface sediments below the limit of detection. Approximately 80% of authigenic Ba is remineralized during early diagenesis on the seabed, much more than is expected for conditions of high sediment mass accumulation rate that exist in the study area. Extensive remineralization during early diagenesis, combined with large corrections required to remove the aluminosilicate contribution to the concentrations of Cu, Ni, and Ba in sediments, preclude the successful use of down-core profiles of these trace metals to reconstruct past changes in export production of the Middle Atlantic Bight. Similar problems are likely to plague paleoproductivity reconstructions in other ocean-margin regions, or wherever high fluxes of aluminosilicate phases occur.

  8. German Bight residual current variability on a daily basis: principal components of multi-decadal barotropic simulations

    NASA Astrophysics Data System (ADS)

    Callies, Ulrich; Gaslikova, Lidia; Kapitza, Hartmut; Scharfe, Mirco

    2016-08-01

    Time variability of Eulerian residual currents in the German Bight (North Sea) is studied drawing on existing multi-decadal 2D barotropic simulations (1.6 km resolution) for the period Jan. 1958-Aug. 2015. Residual currents are calculated as 25 h means of velocity fields stored every hour. Principal component analysis (PCA) reveals that daily variations of these residual currents can be reasonably well represented in terms of only 2-3 degrees of freedom, partly linked to wind directions. The daily data refine monthly data already used in the past. Unlike existing classifications based on subjective assessment, numerical principal components (PCs) provide measures of strength and can directly be incorporated into more comprehensive statistical data analyses. Daily resolution in particular fits the time schedule of data sampled at the German Bight long-term monitoring station at Helgoland Roads. An example demonstrates the use of PCs and corresponding empirical orthogonal functions (EOFs) for the interpretation of short-term variations of these local observations. On the other hand, monthly averaging of the daily PCs enables to link up with previous studies on longer timescales.

  9. German Bight residual current variability on a daily basis: principal components of multi-decadal barotropic simulations

    NASA Astrophysics Data System (ADS)

    Callies, Ulrich; Gaslikova, Lidia; Kapitza, Hartmut; Scharfe, Mirco

    2017-04-01

    Time variability of Eulerian residual currents in the German Bight (North Sea) is studied drawing on existing multi-decadal 2D barotropic simulations (1.6 km resolution) for the period Jan. 1958-Aug. 2015. Residual currents are calculated as 25 h means of velocity fields stored every hour. Principal component analysis (PCA) reveals that daily variations of these residual currents can be reasonably well represented in terms of only 2-3 degrees of freedom, partly linked to wind directions. The daily data refine monthly data already used in the past. Unlike existing classifications based on subjective assessment, numerical principal components (PCs) provide measures of strength and can directly be incorporated into more comprehensive statistical data analyses. Daily resolution in particular fits the time schedule of data sampled at the German Bight long-term monitoring station at Helgoland Roads. An example demonstrates the use of PCs and corresponding empirical orthogonal functions (EOFs) for the interpretation of short-term variations of these local observations. On the other hand, monthly averaging of the daily PCs enables to link up with previous studies on longer timescales.

  10. Characterizing Wave- and Current-Induced Bottom Shear Stress: U.S. Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Dalyander, S.; Butman, B.

    2011-12-01

    The combined action of waves and currents at the seabed creates bottom shear stress, impacting local geology, habitat, and anthropogenic use. In this study, a methodology is developed to characterize the magnitude of benthic disturbance based on spatially and seasonally-resolved statistics (mean, standard deviation, 95th percentile) of wave-current bottom shear stress. The frequency of stress forcing is used to distinguish regions dominated by storms (return interval longer than 33 hours) from those dominated by the tides (periods shorter than 33 hours). In addition, the relative magnitude of the contribution to stress from waves, tides, and storm-driven currents is investigated by comparing wave stress, tidal current stress, and stress from the residual current (currents with tides removed), as well as through cross-correlation of wave and current stress. The methodology is applied to numerical model time-series data for the Middle Atlantic Bight (MAB) off the U.S. East Coast for April 2010 to April 2011; currents are provided from the Integrated Ocean Observing System (IOOS) operational hydrodynamic forecast Experimental System for Predicting Shelf and Slope Optics (ESPreSSO) and waves are provided from a Simulating WAves Nearshore (SWAN) hindcast developed for this project. Spatial resolution of the model is about 5 km and time-series wave and current data are at 1 and 2-hours respectively. Regions of the MAB delineated by stress characteristics include a tidally-dominated shallow region with relative high stress southeast of Massachusetts over Nantucket Shoals; a coastal band extending offshore to about 30 m water depth dominated by waves; a region dominated by waves and wind-driven currents offshore of the Outer Banks of North Carolina; and a low stress region southeast of Long Island, approximately coincident with an area of fine-grained sediments called the "Mud Patch". Comparison of the stress distribution with surface sediment texture data shows that

  11. Population ecology of nitrifying archaea and bacteria in the Southern California Bight.

    PubMed

    Beman, J Michael; Sachdeva, Rohan; Fuhrman, Jed A

    2010-05-01

    Marine Crenarchaeota are among the most abundant microbial groups in the ocean, and although relatively little is currently known about their biogeochemical roles in marine ecosystems, recognition that Crenarchaeota posses ammonia monooxygenase (amoA) genes and may act as ammonia-oxidizing archaea (AOA) offers another means of probing the ecology of these microorganisms. Here we use a time series approach combining quantification of archaeal and bacterial ammonia oxidizers with bacterial community fingerprints and biogeochemistry, to explore the population and community ecology of nitrification. At multiple depths (150, 500 and 890 m) in the Southern California Bight sampled monthly from 2003 to 2006, AOA were enumerated via quantitative PCR of archaeal amoA and marine group 1 Crenarchaeota 16S rRNA genes. Based on amoA genes, AOA were highly variable in time - a consistent feature of marine Crenarchaeota- however, average values were similar at different depths and ranged from 2.20 to 2.76 x 10(4) amoA copies ml(-1). Archaeal amoA genes were correlated with Crenarchaeota 16S rRNA genes (r(2) = 0.79) and the slope of this relationship was 1.02, demonstrating that the majority of marine group 1 Crenarchaeota present over the dates and depths sampled possessed amoA. Two AOA clades were specifically quantified and compared with betaproteobacterial ammonia-oxidizing bacteria (beta-AOB) amoA genes at 150 m; these AOA groups were found to strongly co-vary in time (r(2) = 0.70, P < 0.001) whereas AOA : beta-AOB ratios ranged from 13 to 5630. Increases in the AOA : beta-AOB ratio correlated with the accumulation of nitrite (r(2) = 0.87, P < 0.001), and may be indicative of differences in substrate affinities and activities leading to periodic decoupling between ammonia and nitrite oxidation. These data capture a dynamic nitrogen cycle in which multiple microbial groups appear to be active participants.

  12. Atlantic surfclam connectivity within the Middle Atlantic Bight: Mechanisms underlying variation in larval transport and settlement

    NASA Astrophysics Data System (ADS)

    Zhang, Xinzhong; Munroe, Daphne; Haidvogel, Dale; Powell, Eric N.

    2016-05-01

    Larval transport and settlement have been shown in various studies to be essential in determining population abundance and connectivity for benthic invertebrates. This transport is influenced by both the physical environment and biological behavior. The Atlantic surfclam, Spisula solidissima, is a commercially important benthic invertebrate fishery species along the U.S northeastern coast. In this study, a physical circulation model is coupled to a surfclam larval model to investigate the dynamics of larval transport and settlement within the Middle Atlantic Bight (MAB) shelf in 2006. The main physical mechanisms causing variability in larval transport and settlement are also examined. Model results show that surfclam larvae released from July to early October experience relatively larger settlement rates, due to higher average temperatures experienced by larvae. Larval along-shore transport exhibits a mean down-coast pattern following the coastal current from the northeast to the southwest, with most high-frequency (period of 2-10 days) variations caused by fluctuations in the along-shore surface wind stress, and with seasonal variations speculated to be driven mainly by changes in the across-shelf density gradient. Larval across-shelf movement is highly correlated with the along-shore surface wind stress mediated by coastal upwelling and downwelling episodes, but the correlation is further dependent on the vertical distribution of the larvae, particularly their position relative to the thermocline. Most surfclam larvae released from the Middle Atlantic shelf stay below the thermocline and experience a net onshore transport during the summer-stratified season when upwelling-favorable wind forcing dominates. A proposed critical value of water temperature at the thermocline successfully regulates the observed patterns of vertical distribution of surfclam larvae and their across-shelf movement off the New Jersey and South Virginia shelves; that is, when the water

  13. Cold anticyclonic eddies formed from cold pool water in the southern Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Flagg, Charles N.; Wallace, Douglas; Kolber, Zbigniew

    1997-12-01

    AVHRR satellite imagery of the southern Mid-Atlantic Bight during May 1993 revealed a large area of cold water over the shelf break and slope that appeared to spin up into a series of southward propagating anticyclonic eddies. The eddies had diameters of 35-45 km at the surface and moved southward at about 20 cm/sec. A radial TOYO CTD (to 50m) and ADCP velocity (to 400m) transect was conducted across the southern-most of these eddies. The upper 50 meters had minimum temperatures of less than 7°C and salinities of about 33 pss, characteristics similar to cold pool waters usually found over the continental shelf. ADCP velocity data from one of the eddies revealed anticyclonic flow extending to a depth of about 250m. The transport of cold pool water by the eddies was estimated to be 0.1 to 0.2 Sv which is of the same order as the annual mean alongshore transport of shelf water in this region. The origin of the deeper water within the eddy is unlikely to be the continental shelf because the shelf break is less than 100 m. The depth and velocity profiles along the TOYO transect were consistent with the constant potential vorticity eddy model of Flierl (1979) although the source of the eddy kinetic energy is uncertain. The cause for the exodus of cold pool water from the shelf, which extended northward to at least 38°N, is unclear but must involve the establishment of an alongshore baroclinic pressure gradient against the usual southwestward shelf flow. It is possible that the intrusion of Gulf Stream waters onto the shelf near Cape Hatteras was a precursor of this off shelf transport. The southern-most eddy was marked by high biological productivity and very high oxygen supersaturation. The phytoplankton bloom detected within the exported cold pool water, located over the continental slope, suggests a mechanism whereby production fueled by nutrients derived from the shelf can be locally exported into deep water.

  14. Improving Significant Wave Height detection for Coastal Satellite Altimetry: validation in the German Bight.

    NASA Astrophysics Data System (ADS)

    Passaro, Marcello; Benveniste, Jérôme; Cipollini, Paolo; Fenoglio-Marc, Luciana

    For more than two decades, it has been possible to map the Significant Wave Height (SWH) globally through Satellite Altimetry. SWH estimation is possible because the shape of an altimetric waveform, which usually presents a sharp leading edge and a slowly decaying trailing edge, depends on the sea state: in particular, the higher the sea state, the longer the rising time of the leading edge. The algorithm for SWH also depends on the width of the point target response (PTR) function, which is usually approximated by a constant value that contributes to the rising time. Particularly challenging for SWH detection are coastal data and low sea states. The first are usually flagged as unreliable due to land and calm water interference in the altimeter footprint; the second are characterized by an extremely sharp leading edge that is consequently poorly sampled in the digitalized waveform. ALES, a new algorithm for reprocessing altimetric waveforms, has recently been validated for sea surface height estimation (Passaro et al. 2014). The aim of this work is to check its validity also for SWH estimation in a particularly challenging area. The German Bight region presents both low sea state and coastal issues and is particularly suitable for validation, thanks to the extended network of buoys of the Bundesamt für Seeschifffahrt und Hydrographie (BSH). In-situ data include open sea, off-shore and coastal sea conditions, respectively at the Helgoland, lighthouse Alte Weser and Westerland locations. Reprocessed data from Envisat, Jason-1 and Jason-2 tracks are validated against those three buoys. The in-situ validation is applied both at the nearest point and at points along-track. The skill metrics is based on bias, standard deviation, slope of regression line, scatter index, number of cycles with correlation larger than 90%. The same metrics is applied to the altimeter data obtained by standard processing and the validation results are compared. Data are evaluated at high

  15. The role of zooplankton in the cycling and remineralization of chemical materials in the Southern California Bight

    SciTech Connect

    Small, L.F.; Huh, Chih-An.

    1988-01-01

    The overall objective of our research is to understand the transport pathways and mass balances of selected metabolically active and inactive chemical species in the Santa Monica/San Pedro Basins. One focus of our study is to examine the role of zooplankton and micronekton in the cycling and remineralization of chemical materials in the Southern California Bight, with particular reference to C, N and certain radionuclides and trace metals. A second focus is to examine these same radionuclides and trace metals in other important reservoirs. Knowledge of the rates and routes of transfer of these nuclides and metals through these reservoirs should lead to a cogent model for these elements in SM/SP Basins. Our zooplankton C and N data, should lead ultimately to a model of C and N cycling in the upper water column. Our sediment core data will lead to the construction of mass balances and budgets in the SM/SP Basins. 4 refs.

  16. Ecological evaluation of proposed reference sites in the New York Bight, Great South Bay, and Ambrose Light, New York

    SciTech Connect

    Gardiner, W.W.; Barrows, E.S.; Word, J.Q.

    1996-10-01

    The current reference site used in evaluations of dredged material proposed for open water disposal in the New York Bight is the Mud Dump Reference Site. The sediment at this reference site is predominantly sand. The US Army Corps of Engineers New York District is considering designation of a new reference site that (1) includes a fine-grained component, believed to be necessary for adequate amphipod survival in laboratory tests, (2) better reflects the physical characteristics of the fine-grained sediment dredged from the New York/New Jersey Harbor and (3) is further removed from the Mud Dump Site than the current Mud Dump Reference Site. The Battelle Marine Science Laboratory was requested to characterize sediment collected from seven candidate reference sites during two study phases. This report presents the results of physical, chemical, and toxicological characterizations of sediment from these sites in comparisons with those of the original Mud Dump Reference Site.

  17. Sulphur diagenesis in the sediments of the Kiel Bight, SW Baltic Sea, as reflected by multiple stable sulphur isotopes.

    PubMed

    Strauss, Harald; Bast, Rebecca; Cording, Anja; Diekrup, David; Fugmann, Artur; Garbe-Schönberg, Dieter; Lutter, Andreas; Oeser, Martin; Rabe, Katharina; Reinke, Debora; Teichert, Barbara M A; Westernströer, Ulrike

    2012-01-01

    In this work, the biogeochemistry of marine sediments from the Kiel Bight, coastal SW Baltic Sea, is studied based on the abundance and isotopic composition of organic carbon and different forms of sedimentary sulphur. Active bacterial sulphate reduction, partly under sulphate-limiting conditions, is evident from paired δ(34)S and δ(18)O values of pore water sulphate. The resulting pore water sulphide is partly precipitated as acid-volatile iron sulphide and subsequently forms sedimentary pyrite, partly serves in later diagenetic sulphurisation of organic matter, or remains dissolved in the pore water, all evident from the respective δ(34)S values. Microbial sulphate turnover is associated with an apparent isotopic fractionation between dissolved sulphate and dissolved sulphide (Δ(34)S) that varies between 46 and 66‰.

  18. Reinterpretation of the Franklin "Shore" in the Mid-Atlantic bight as a paleo-shelf edge

    NASA Astrophysics Data System (ADS)

    Goff, John A.; Austin, James A.; Fulthorpe, Craig S.

    2013-06-01

    The presence of a scarp sub-parallel to, but landward of, the modern continental shelf edge is commonly used to infer a fossil shoreline preserved during the course of a sea level rise and shoreline transgression. Advances in geophysical imaging, including bathymetric data compilations and high-resolution acoustic reflection, merit a review of these scarps and their origins. We focus on the Mid-Atlantic Bight, east coast of the United States, where four siliciclastic fossil shorelines have previously been identified and are still cited as such in the literature. Two of the scarps are not in evidence in the newest compilation of bathymetry. A third, the Mid-Shelf Scarp, is of limited extent and, as established in previous studies, represents a seaward edge of delta lobes rather than a fossil shoreline. The fourth, the Franklin Scarp, is a major topographic feature that extends from Cape Hatteras to Cape Cod. However, morphologic and stratigraphic evidence leads us to conclude that, instead of a fossil shore, this scarp represents a paleo-shelf edge, likely formed during the MIS 4 lowstand (~65 ka). Both the modern shelf edge and the Franklin Scarp deepen to the north by ~50 m, while systematically maintaining a depth offset of ~40 m. This observation, which cannot be attributed to glacial isostatic processes, is enigmatic but suggests fundamental environmental controls on the depth of the clinoform rollover. Furthermore, all the major shelf-indenting canyons in the Mid-Atlantic Bight are bounded landward by the Franklin Scarp, which suggests that interfluve progradation may be a more significant mechanism for growth of these canyons than headward erosion.

  19. Coastal flooding: impact of waves on storm surge during extremes - a case study for the German Bight

    NASA Astrophysics Data System (ADS)

    Staneva, Joanna; Wahle, Kathrin; Koch, Wolfgang; Behrens, Arno; Fenoglio-Marc, Luciana; Stanev, Emil V.

    2016-11-01

    This study addresses the impact of wind, waves, tidal forcing and baroclinicity on the sea level of the German Bight during extreme storm events. The role of wave-induced processes, tides and baroclinicity is quantified, and the results are compared with in situ measurements and satellite data. A coupled high-resolution modelling system is used to simulate wind waves, the water level and the three-dimensional hydrodynamics. The models used are the wave model WAM and the circulation model GETM. The two-way coupling is performed via the OASIS3-MCT coupler. The effects of wind waves on sea level variability are studied, accounting for wave-dependent stress, wave-breaking parameterization and wave-induced effects on vertical mixing. The analyses of the coupled model results reveal a closer match with observations than for the stand-alone circulation model, especially during the extreme storm Xaver in December 2013. The predicted surge of the coupled model is significantly enhanced during extreme storm events when considering wave-current interaction processes. This wave-dependent approach yields a contribution of more than 30 % in some coastal areas during extreme storm events. The contribution of a fully three-dimensional model compared with a two-dimensional barotropic model showed up to 20 % differences in the water level of the coastal areas of the German Bight during Xaver. The improved skill resulting from the new developments justifies further use of the coupled-wave and three-dimensional circulation models in coastal flooding predictions.

  20. Stable isotope signatures and element stoichiometry of Fucus vesiculosus as indicators for environmental conditions in the Kiel Bight, Baltic Sea

    NASA Astrophysics Data System (ADS)

    Winde, Vera; Mahler, Annika; Voss, Maren; Böttcher, Michael E.

    2014-05-01

    In the frame of the BMBF project BIOACID II we aim for an understanding of the natural distribution and variation of isotopic composition and C-N-S stoichiometry in Fucus vesiculosus growing around the coast line of the Kiel fjord (part of the Kiel bight). Environmental conditions (aquatic chemistry, temperature, salinity) were monitored, too. Some changes in aquatic chemistry are related to stress factors like human activity (e.g., waste input) and further factors leading to specific changes in the composition of Fucus vesiculosus. Sampling was carried out at different stations at the west and east coast of the Kiel Fjord. For each sampling station the aquatic chemistry (TA, pH, salinity, d13C(DIC), main and trace elements and nutrients) as well as the composition of the Fucus organic tissues (stoichiometry and stable isotope composition of carbon, nitrogen) are analysed. The Fucus tissue was sampled in three size classes (small, medium, large). It is shown, that Fucus vesiculosus indicates clear differences in the N contents and stable isotopes between the west and the east site of the Kiel Fjord. Stable nitrogen isotope signatures in Fucus vesiculosus, are useful proxies to identify the influence factors in the Fucus habitat. From the data it is obtained that the influence of human activity (wastewater treatment plant, harbour), small stream and drainage channels, which flow from the near coastal area into the bight, leads to different Fucus vesiculosus compositions. In future work, it is intended to extend the investigation to trace element signatures to further estimate environmental impacts.

  1. Sediment accumulation on the Southern California Bight continental margin during the twentieth century

    USGS Publications Warehouse

    Alexander, C.R.; Lee, H.J.

    2009-01-01

    Sediment discharged into the portion of the Southern California Bight extending from Santa Barbara to Dana Point enters a complex system of semi-isolated coastal cells, narrow continental shelves, submarine canyons, and offshore basins. On both the Santa Monica and San Pedro margins, 210Pb accumulation rates decrease in an offshore direction (from ??0.5 g cm-2yr-1 to 0.02 g cm-2yr -1), in concert with a fining in sediment grain size (from 4.5?? to 8.5??), suggesting that offshore transport of wave-resuspended material occurs as relatively dilute nepheloid layers and that hemiplegic sedimentation dominates the supply of sediment to the outer shelf, slope, and basins. Together, these areas are effectively sequestering up to 100% of the annual fluvial input. In contrast to the Santa Monica margin, which does not display evidence of mass wasting as an important process of sediment delivery and redistribution, the San Pedro margin does provide numerous examples of failures and mass wasting, suggesting that intraslope sediment redistribution may play a more important role there. Basin deposits in both areas exhibit evidence of turbidites tentatively associated with both major floods and earthquakes, sourced from either the Redondo Canyon (San Pedro Basin) or Dume Canyon (Santa Monica Basin). On the Palos Verdes shelf, sediment-accumulation rates decrease along and across the shelf away from the White's Point outfall, which has been a major source of contaminants to the shelf deposits. Accumulation rates prior to the construction of the outfall were ??0.2 g cm-2yr-1 and increased 1.5-3.7 times during peak discharges from the outfall in 1971. The distal rate of accumulation has decreased by ??50%, from 0.63 g cm -2yr-1 during the period 1971-1992 to 0.29 g cm -2yr-1 during the period 1992-2003. The proximal rate of accumulation, however, has only decreased ??10%, from 0.83 g cm -2yr-1 during the period 1971-1992 to 0.73 g cm -2yr-1 during the period 1992-2003. Effluent

  2. Delineation of estuarine fronts in the German Bight using airborne laser-induced water Raman backscatter and fluorescence of water column constituents

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1982-01-01

    The acquisition and application of airborne laser induced emission spectra from German Bight water during the 1979 MARSEN experiment is detailed for the synoptic location of estuarine fronts. The NASA Airborne Oceanographic Lidar (AOL) was operated in the fluorosensing mode. A nitrogen laser transmitter at 337.1 nm was used to stimulate the water column to obtain Gelbstoff or organic material fluorescence spectra together with water Raman backscatter. Maps showing the location and relative strength of estuarine fronts are presented. The distribution of the fronts indicates that mixing within the German Bight takes place across a relatively large area. Reasonable agreement between the patterns observed by the AOL and published results are obtained. The limitations and constraints of this technique are indicated and improvements to the AOL fluorosensor are discussed with respect to future ocean mapping applications.

  3. Results from the National Aeronautics and Space Administration remote sensing experiments in the New York Bight, 7-17 April 1975

    NASA Technical Reports Server (NTRS)

    Hall, J. B., Jr. (Compiler); Pearson, A. O. (Compiler)

    1977-01-01

    A cooperative operation was conducted in the New York Bight to evaluate the role of remote sensing technology to monitor ocean dumping. Six NASA remote sensing experiments were flown on the C-54, U-2, and C-130 NASA aircraft, while NOAA obtained concurrent sea truth information using helicopters and surface platforms. The experiments included: (1) a Radiometer/Scatterometer (RADSCAT), (2) an Ocean Color Scanner (OCS), (3) a Multichannel Ocean Color Sensor (MOCS), (4) four Hasselblad cameras, (5) an Ebert spectrometer; and (6) a Reconafax IV infrared scanner and a Precision Radiation Thermometer (PRT-5). The results of these experiments relative to the use of remote sensors to detect, quantify, and determine the dispersion of pollutants dumped into the New York Bight are presented.

  4. Wind effects on coastal zone color scanner chlorophyll patterns in the U.S. Mid-Atlantic Bight during spring 1979

    NASA Technical Reports Server (NTRS)

    Eslinger, David L.; Iverson, Richard L.

    1986-01-01

    Coastal zone color scanner (CZCS) chlorophyll concentration increases in the Mid-Atlantic Bight were associated with high wind speeds in continental shelf waters during March and May 1979. Maximum spring CZCS chlorophyll concentrations occurred during April when the water column was not thermally stratified and were spatially and temporally associated with reductions in wind speed both in onshelf and in offshelf regions. Increased chlorophyll concentrations in offshelf waters were associated with high wind speeds during May when a deep chlorophyll maximum was present. Chlorophyll patchiness was observed on length scales typical of those controlled by biological processes during the April low-wind period but not during March or May when wind speeds were greater. The spring CZCS chlorophyll maximum in the southern portion of the Mid-Atlantic Bight occurred in response to a reduction in mixed layer depth caused by decreased wind speeds and not by increased water column stratification.

  5. Bio-optical profile data report: Southern California Bight Study (SCB2-29) R/V Robert G. Sproul, 20-25 August 1988

    NASA Technical Reports Server (NTRS)

    Collins, Donald J.; Tran, An Van

    1990-01-01

    Time series measurements of the incident surface downwelling irradiance and vertical profiles of the bio-optical properties of the ocean were studied during the 29th cruise of the Southern California Bight Study (SCBS) during the period of August 20-25, 1988. A summary of these data is presented to permit investigators an overview of the data collected. The data are available in digital form for scientific investigators.

  6. Blue and Fin Whale Habitat Modeling from Long-Term Year-Round Passive Acoustic Data from the Southern California Bight

    DTIC Science & Technology

    2013-09-30

    collected using High-frequency Acoustic Recording Packages ( HARPs ) deployed at sixteen locations in the Southern California Bight (Figure 1). We have been...National Data Buoy Center for the parts of the SCB region with HARP deployments. Figure 1. Sixteen HARP deployment locations (black squares...Mountain), we developed propagation models for areas around each of the HARP deployment locations to investigate the characteristics of propagation

  7. Blue and Fin Whale Habitat Modeling from Long-Term Year-Round Passive Acoustic Data from the Southern California Bight

    DTIC Science & Technology

    2015-09-30

    Round Passive Acoustic Data from the Southern California Bight Ana Širović and John A. Hildebrand Scripps Institution of Oceanography UCSD 9500...passive acoustic and remotely sensed data available for the SCB. APPROACH Passive acoustic data have been collected using High-frequency Acoustic ...whale calls in the area of the SCB between 32° and 34° 20’ N from passive acoustic recordings collected year-round between 2006 and 2012 (Širović et

  8. Assessment of observed and perceived changes in ecosystems over time, with special reference to the Sylt-Rømø Bight, German Wadden Sea

    NASA Astrophysics Data System (ADS)

    Baird, Dan

    2012-08-01

    Examples of state changes in three aquatic ecosystems (the Neuse River estuary, NC, USA, the Kromme River estuary (St. Francis Bay, South Africa), the St. Marks National Wildlife Refuge, FL, USA) over time have been quantitatively assessed using ecological network analysis (ENA). A suite of ENA indices were compared among the multiple states of these ecosystems to illustrate the usefulness of ENA for describing differences among system states. Quantitative network models were constructed for the Sylt-Rømø Bight ecosystem and for the mussel bed subsystem of the Bight, depicting standing stocks of the living and non-living components and flow of carbon [a surrogate for energy] between them. These models consist of 59 compartments, and were assessed by means of ENA protocols. The impact of invasive species, such as the Pacific oyster, Crassostrea gigas, on existing mussel beds [of Mytilus edulis], and on predators [mainly birds] dependent on mussels for energy were assessed using AUTOMOD, a routine that predict the impact of species on each other within the ecosystem model. Predictive modelling clearly shows variability in bird biomass due to change in abundance of their important prey species at lower trophic levels. The simulations illustrated that the numbers of eider duck and oystercatcher in the Bight could be reduced to 50% of their current abundance within about 10 years at a 20%-40% reduction in prey biomass. Ecosystem properties calculated using ENA for the initial and alternate state of the Bight and the mussel beds after a simulated reduction of 40% in prey biomass show a decline in virtually all metrics (Total System Throughput, Development Capacity, Ascendency, Redundancy), system trophic efficiency, cycling, and system ratios (e.g. Average Mutual Information, Flow Diversity, Food Web Connectance).

  9. Meteorological forcing of the annual MSL cycle and its impacts on flood risk in the German Bight

    NASA Astrophysics Data System (ADS)

    Dangendorf, S.; Mudersbach, C.; Wahl, T.; Jensen, J.

    2012-04-01

    Dangendorf et al. (under review) recently analyzed the annual mean sea level (MSL) cycle for 13 tide gauges located in the German Bight. Using an empirical method they did not find any significant long-term changes in the amplitude of the annual cycle, but a large inter-annual variability. Furthermore, it has been recognized that in the last two decades the occurrence time of the annual peak has been shifted from the late autumn into the months from January and February. This is important, since changes in the annual MSL cycle may affect the heights of storm surges and thereby the flood risk in coastal areas. The shift has been triggered by large trends during the winter (January to March) months, which have been considerably higher compared to the remaining months. The authors explained this shift with changing pressure conditions over the North Atlantic, which lead to anomalous large trends in the North Atlantic Oscillation index (NAO) in the period from 1951 to 2008. However, as mentioned by Suursaar and Soosäär (2007), the NAO is not a single forcing factor affecting sea level. The NAO rather influences sea level over Northern Europe through different related meteorological parameters, such as wind, sea level pressure (SLP), or precipitation. In this study we use time series of local wind (u and v-components), SLP and precipitation from the 20th century reanalysis data sets (Compo et al. 2011) to assess the contribution of the different parameters on the annual MSL cycle in the German Bight. A multiple regression analysis is used to describe the influences on seasonal MSL variability and trends for the period from 1951 to 2008. The influence of the different parameters varies throughout the different seasons. The u-wind is the dominating factor in every season (r > 0.7). SLP is used as a second predictor in winter, spring and autumn, while precipitation has considerably additional influences during spring and summer. The v-wind is only important during the

  10. Distribution of planktonic cnidarians in response to South Atlantic Central Water intrusion in the South Brazilian Bight

    NASA Astrophysics Data System (ADS)

    Nogueira Júnior, Miodeli; Brandini, Frederico P.; Codina, Juan C. U.

    2014-10-01

    Five oceanographic cruises were made between November 2005 and June 2006, sampling a cross-shelf transect off the South Brazilian Bight (SBB; 26°46‧S) to follow the seasonal development of the South Atlantic Central Water (SACW) intrusion over the shelf and its influence on the assemblage of planktonic cnidarians. An onshore wind-driven bottom intrusion of the SACW was clearly perceptible, reaching the coast in January. From March onward, the SACW influence was gradually displaced seaward due to wind and tidal mixing. By late June the SACW influence was offshore and the inshore was dominated by low-salinity waters (<34.5). The abundance, distribution, and general taxonomic composition of both medusae and siphonophores were strongly influenced by the onshore intrusion of the SACW. An inshore-offshore gradient was clear. The Canonical Correspondence Analysis suggested that coastal species - dominated by Liriope tetraphylla, actinula larvae and Muggiaea kochi - were mostly related to food availability and a vertically mixed environment inshore, and their abundance and extent were reduced during intrusion periods. In contrast, species with offshore affinities tended to increase their abundance and distribution during intrusion periods, and were mostly related to the presence of thermal stratification and a deep chlorophyll maximum layer. Most of these offshore species, such as Aglaura hemistoma, Rhopalonema velatum and many calycophorans, are associated with the warm upper layer. However, high concentrations of large (>20 mm in diameter) Solmaris corona were observed exclusively in cold waters, suggesting this medusa is a SACW indicator.

  11. Seasonal and spatial patterns of Penilia avirostris and three tunicate species in the southern Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Ambler, Julie W.; Kumar, Ajoy; Moisan, Tiffany A.; Aulenbach, Donielle L.; Day, Melissa C.; Dix, Stephanie A.; Winsor, Michele A.

    2013-10-01

    The cladoceran Penilia avirostris and three tunicate species, Oikopleura dioica, Dolioletta gegenbauri and Thalia democratica, form a mesozooplankton group which ingests a wide range of particles from pico- to micro- plankton, grows rapidly due to asexual reproduction, and thus can have major impacts on phytoplankton populations. These four zooplankton species were the most abundant tunicate and cladoceran species in a study where zooplankton were sampled biweekly at five stations across the inner continental shelf in the Mid-Atlantic Bight in 2005, 2006 and 2007. Vertical tows were taken at shallow stations and depth stratified vertical tows at stations >10 m. P. avirostris and O. dioica had highly predictable seasonal cycles with peak abundances in July and August. D. gegenbauri also was present during this time period if upwelling favorable winds were present, which implies cross shelf transport from source populations in slope waters and the Gulf Stream. T. democratica only appeared in pulses when southerly winds were increasing in strength. The co-occurrence P. avirostris and the tunicate species with abundant Synechococcus and heterotrophic nanoflagellates during highly stratified summer conditions provide potential connections to microbial food webs as well as grazing opportunities on event scale blooms of dinoflagellate and diatoms species present in the area.

  12. Nontargeted Biomonitoring of Halogenated Organic Compounds in Two Ecotypes of Bottlenose Dolphins (Tursiops truncatus) from the Southern California Bight

    PubMed Central

    2015-01-01

    Targeted environmental monitoring reveals contamination by known chemicals, but may exclude potentially pervasive but unknown compounds. Marine mammals are sentinels of persistent and bioaccumulative contaminants due to their longevity and high trophic position. Using nontargeted analysis, we constructed a mass spectral library of 327 persistent and bioaccumulative compounds identified in blubber from two ecotypes of common bottlenose dolphins (Tursiops truncatus) sampled in the Southern California Bight. This library of halogenated organic compounds (HOCs) consisted of 180 anthropogenic contaminants, 41 natural products, 4 with mixed sources, 8 with unknown sources, and 94 with partial structural characterization and unknown sources. The abundance of compounds whose structures could not be fully elucidated highlights the prevalence of undiscovered HOCs accumulating in marine food webs. Eighty-six percent of the identified compounds are not currently monitored, including 133 known anthropogenic chemicals. Compounds related to dichlorodiphenyltrichloroethane (DDT) were the most abundant. Natural products were, in some cases, detected at abundances similar to anthropogenic compounds. The profile of naturally occurring HOCs differed between ecotypes, suggesting more abundant offshore sources of these compounds. This nontargeted analytical framework provided a comprehensive list of HOCs that may be characteristic of the region, and its application within monitoring surveys may suggest new chemicals for evaluation. PMID:25526519

  13. Coastal ocean climatology of temperature and salinity off the Southern California Bight: Seasonal variability, climate index correlation, and linear trend

    NASA Astrophysics Data System (ADS)

    Kim, Sung Yong; Cornuelle, Bruce D.

    2015-11-01

    A coastal ocean climatology of temperature and salinity in the Southern California Bight is estimated from conductivity-temperature-depth (CTD) and bottle sample profiles collected by historical California Cooperative Oceanic Fisheries Investigation (CalCOFI) cruises (1950-2009; quarterly after 1984) off southern California and quarterly/monthly nearshore CTD surveys (within 30 km from the coast except for the surfzone; 1999-2009) off San Diego and Los Angeles. As these fields are sampled regularly in space, but not in time, conventional Fourier analysis may not be possible. The time dependent temperature and salinity fields are modeled as linear combinations of an annual cycle and its five harmonics, as well as three standard climate indices (El Niňo-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), North Pacific Gyre Oscillation (NPGO)), the Scripps Pier temperature time series, and a mean and linear trend without time lags. Since several of the predictor indices are correlated, the indices are successively orthogonalized to eliminate ambiguity in the identification of the contributed variance of each component. Regression coefficients are displayed in both vertical transects and horizontal maps to evaluate (1) whether the temporal and spatial scales of the two data sets of nearshore and offshore observations are consistent and (2) how oceanic variability at a regional scale is related to variability in the nearshore waters. The data-derived climatology can be used to identify anomalous events and atypical behaviors in regional-scale oceanic variability and to provide background ocean estimates for mapping or modeling.

  14. Seafloor monitoring west of Helgoland (German Bight, North Sea) using the acoustic ground discrimination system RoxAnn

    NASA Astrophysics Data System (ADS)

    Hass, H. Christian; Mielck, Finn; Fiorentino, Dario; Papenmeier, Svenja; Holler, Peter; Bartholomä, Alexander

    2016-11-01

    Marine habitats of shelf seas are in constant dynamic change and therefore need regular assessment particularly in areas of special interest. In this study, the single-beam acoustic ground discrimination system RoxAnn served to assess seafloor hardness and roughness, and combine these parameters into one variable expressed as RGB (red green blue) color code followed by k-means fuzzy cluster analysis (FCA). The data were collected at a monitoring site west of the island of Helgoland (German Bight, SE North Sea) in the course of four surveys between September 2011 and November 2014. The study area has complex characteristics varying from outcropping bedrock to sandy and muddy sectors with mostly gradual transitions. RoxAnn data enabled to discriminate all seafloor types that were suggested by ground-truth information (seafloor samples, video). The area appears to be quite stable overall; sediment import (including fluid mud) was detected only from the NW. Although hard substrates (boulders, bedrock) are clearly identified, the signal can be modified by inclination and biocover. Manually, six RoxAnn zones were identified; for the FCA, only three classes are suggested. The latter classification based on `hard' boundaries would suffice for stakeholder issues, but the former classification based on `soft' boundaries is preferred to meet state-of-the-art scientific objectives.

  15. Simulation analysis of moored fluorometer time series from the Mid-Atlantic Bight during 1987--1990

    SciTech Connect

    Walsh, J.J.

    1990-01-01

    The goal of the previous research during 1987-1990 within the DOE (Department of Energy) Shelf Edge Exchange Processes (SEEP) program in the Mid-Atlantic Bight was to understand the physical and biogeochemical processes effecting the diffusive exchange of the proxies of energy-related, by-products associated with particulate matter between estuarine, shelf, and slope waters on this continental margin. As originally envisioned in the SEEP program plan, SEEP-III would take place at Cape Hatteras to study the advective exchange of materials by a major boundary current. One problem of continuing interest is the determination of the local assimilative capacity of slope waters and sediments off the eastern seaboard of the US to lengthen the pathway between potentially harmful energy by-products and man. At basin scales, realistic specification of the lateral transport by western boundary currents of particulate matter is a necessary input to global models of carbon/nitrogen cycling. Finally, at these global scales, the generic role of continental margins in cycling greenhouse gases, e.g. CO{sub 2}, CH{sub 4}, and N{sub 2}O, is now of equal interest. This continuing research of model construction and evaluation within the SEEP program focuses on all three questions at local, regional, and basin scales. Results from SEEP-I and II are discussed as well as plans for SEEP-III. 14 figs., 3 tabs.

  16. Long-term impact of bottom trawling on pelagic-benthic coupling in the southern North Sea (German Bight)

    NASA Astrophysics Data System (ADS)

    Friedrich, Jana; van Beusekom, Justus E. E.; Neumann, Andreas; Naderipour, Celine; Janssen, Felix; Ahmerkamp, Soeren; Holtappels, Moritz; Schueckel, Ulrike

    2016-04-01

    The southern North Sea, and the German Bight, has been systematically bottom-trawled at least since the late 19th century (Christiansen, 2009; Reiss et al., 2009; Kröncke 2011; Emeis et al., 2015, Neumann et al., 2016). As a result, benthic habitats and benthic biogenic structures created by bivalves, polychaetes and hydroids where destroyed or reduced. The parallel removal of hard substrate (gravel and boulders) avoids the resettlement of hard-substrate depended species. For example, the Oyster ground, a huge oyster bank a hundred years ago (Olsen, 1883), turned into a muddy depression today. In addition, shallow depth of max 40 m, strong tidal currents and frequent storms result in a high-energy environment with low sedimentation rates and recurrent sediment resuspension. The decrease in benthic filtering capacity by disturbance in epifauna and bottom roughness (Callaway et al., 2007) apparently influence pelagic-benthic coupling of biogeochemical fluxes. Heip et al. (1995) indicate that benthic respiration at depths prevailing in the German Bight accounts for 10-40% of total respiration, whereas pelagic respiration accounts for 60-90%. Previous estimates are in the middle of this range (Heip et al., 1995). To test these hypotheses and to assess the partitioning of benthic and pelagic processes, and the factors influencing organic matter mineralization, we measured pelagic production and respiration based on Winkler titration, in-situ benthic fluxes using chamber landers, we did ex-situ incubations of intact sediment cores and analysed still images from a towed benthic video sled. In addition, O2 fluxes in permeable sediments were estimated by integrating the volumetric rate measurements of the upper sediment layer over in-situ microsensor-measured O2 penetration depth. Our current results show significant seasonality in benthic respiration, with highest rates in summer and lowest rates in winter. No significant differences in total benthic respiration rates

  17. Temporal and spatial variation of hyperiid amphipod assemblages in response to hydrographic processes in the Panama Bight, eastern tropical Pacific

    NASA Astrophysics Data System (ADS)

    Valencia, Bellineth; Lavaniegos, Bertha; Giraldo, Alan; Rodríguez-Rubio, Efraín

    2013-03-01

    The variability of hyperiid amphipod assemblages was analyzed based on seasonal (dry vs. wet) and spatial differences (neritic vs. oceanic) in the Panama Bight. Four oceanographic cruises were carried out during 2007-2008, two during the dry season (Feb. 2007 and Mar. 2008) and two during the wet season (Sep. 2007 and Sep. 2008). Cooler (<20 °C) and saltier waters (>34 psu) at 30 m were observed during the dry season, while the opposite pattern occurred during the wet season (>25 °C,<33 psu). Seventy hyperiids species were found, with Hyperioides sibaginis and Lestrigonus bengalensis being the most abundant (76%). The structure of the hyperiids assemblages was similar between seasons; this may be due to the interannual variability associated with two ENSO processes (El Niño: Feb. 2007; La Niña: Sep. 2007 and Mar. 2008). Spatially, the structure of the hyperiids assemblages changed during the wet season, as a consequence of the strong neritic-oceanic contrast in salinity, while it was spatially similar during the dry season, as a consequence of species penetration toward the coast promoted by colder and saltier waters. The abundance of hyperiids was significantly correlated with the abundance of gelatinous zooplankton (siphonophores, ctenophores, doliolids and salps), which are commonly used as hosts by this group.

  18. Circulation and exchange processes on the South Atlantic Bight Continental Shelf: Progress report, July 1, 1988 to June 30, 1989

    SciTech Connect

    Lee, T.N.

    1989-03-01

    The work reported here is part of the Department of Energy sponsored Southeast US Continental Shelf Program. The DOE Program is a coordinated, multi-university, interdisciplinary investigation aimed at understanding the physical, chemical and biological processes in the South Atlantic Bight (SAB: east coast continental shelf region from Cape Hatteras to Cape Canaveral). The program is coordinated by Dr. David Menzel of Skidaway Oceanographic Institute. The activities of the other Program Investigators will be discussed briefly under Program Overview. The University of Miami component of the program involves an investigation of the physical processes regulating the transport and exchange of materials in the shelf waters. The guiding scientific objective of this work is to improve the capability for prediction of the physical environment. The principal scientific task is to determine the relative importance of the forces driving shelf circulation and exchange and to measure the shelf waters' response over variable time and space scales. The influence of physical processes on chemical and biological distributions and their interactions is studied through interdisciplinary investigations, joint analysis and interpretation of data and joint publications. 103 refs., 14 figs.

  19. Statistical and dynamical analysis of internal waves on the continental shelf of the Middle Atlantic Bight from Space Shuttle photographs

    NASA Technical Reports Server (NTRS)

    Zheng, Quanan; Yan, Xiao-Hai; Klemas, Vic

    1993-01-01

    The internal waves on the continental shelf on the Middle Atlantic Bight seen on Space Shuttle photographs taken during the STS-40 mission in June 1991 are measured and analyzed. The internal wave field in the sample area has a three-level structure which consists of packet groups, packets, and solitons. An average packet group wavelength of 17.5 km and an average soliton wavelength of 0.6 km are measured. Finite-depth theory is used to derive the dynamic parameters of the internal solitons: the maximum amplitude of 5.6 m, the characteristic phase speed of 0.42 m/s, the characteristic period of 23.8 min, the velocity amplitude of the water particles in the upper and lower layers of 0.13 m/s and 0.030 m/s respectively, and the theoretical energy per unit crest line of 6.8 x 10 exp 4 J/m. The frequency distribution of solitons is triple-peaked rather than continuous. The major generation source is at 160 m water depth, and a second is at 1800 m depth, corresponding to the upper and lower edges of the shelf break.

  20. The modulation of the seasonal cross-shelf sea level variation by the cold pool in the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Sha, Jin; Jo, Young-Heon; Yan, Xiao-Hai; Liu, W. T.

    2015-11-01

    This study explores the influence of the cold pool in the Middle Atlantic Bight (MAB) to cross-shelf sea surface slope by fitting an annual harmonic to temperature and salinity profiles from 1993 to 2012 and compares to the 20 year averaged altimetry sea level anomaly (SLA). The consistency within the bottom temperature, thermal steric height, total steric height, and altimetry observation validates that the cold pool induces a depressed sea level in the middle shelf overlapping with the dominant surface seasonal cycles. Temporally, the cold pool pattern is most apparent in July and August as a result of magnitude competition between the thermal and haline steric height. In addition, Ensemble Empirical Mode Decomposition (EEMD) is employed to reconstruct the altimetry SLA and reveals the middle-shelf depression pattern from single year's SLA data. The locations of the SLA depression from 1993 to 2012 agree with the cold pool locations identified from in situ measurements, suggesting a promising application of altimetry SLA in the cold pool study. Conclusively, this study reveals the modulation of the cross-shelf sea level variation by the cold pool, and contributes to the understanding of the sea level response to water masses on the continental shelf.

  1. Distinct Benthic Community Trends Driven by Particle Transport and Deposition in Mid-Atlantic Bight Canyons, NW Atlantic

    NASA Astrophysics Data System (ADS)

    Demopoulos, A. W.; Robertson, C. M.; Bourque, J. R.; Mienis, F.; Duineveld, G.; Ross, S.; Brooke, S.; Davies, A. J.

    2014-12-01

    The Mid-Atlantic Bight (MAB) is a well-studied region of the U.S. East coast continental margin, rich in submarine canyons. Baltimore and Norfolk canyons were studied during the multidisciplinary Atlantic Deepwater Canyons project through funding from BOEM, NOAA, and USGS. Sediment and water column properties were assessed in the context of canyon physical dynamics and ecosystem ecology. Sediment samples were collected by NIOZ box corer in 2012 and 2013 along canyon axes and comparative adjacent slopes at standardized depths. Sediments were analyzed for grain size, organic content, stable carbon and nitrogen isotopes, chlorophyll a, and benthic infauna. Water column properties were sampled using CTD transects, and benthic landers and moorings positioned along canyon axes. Significant differences in sediment transport regimes were found for each canyon where observed nepheloid layers corresponded to shifts in infaunal community structure. Significant community shifts were observed in stations at depths > 900m in Baltimore Canyon, coinciding with higher organic matter concentrations at depths below the nepheloid layer. In contrast, adjacent slope communities exhibited a more uniform infaunal assemblage where distinct zonation patterns by depth were observed. Preliminary data for Norfolk Canyon suggest very different sediment deposition rates in the canyon and also show clear differences between canyon and slope benthic communities. Geological processes and canyon topography coupled with organic inputs and disturbance events are clear factors in determining benthic infaunal diversity and standing stock dynamics in and around these canyons.

  2. Impact of Lanice conchilega on seafloor microtopography off the island of Sylt (German Bight, SE North Sea)

    NASA Astrophysics Data System (ADS)

    Schönke, M.; Feldens, P.; Wilken, D.; Papenmeier, S.; Heinrich, C.; von Deimling, J. Schneider; Held, P.; Krastel, S.

    2016-12-01

    This study presents a new in situ method to explore the impact of macrofauna on seafloor microtopography and corresponding microroughness based on underwater laser line scanning. The local microtopography was determined with mm-level accuracy at three stations colonised by the tubeworm Lanice conchilega offshore of the island of Sylt in the German Bight (south-eastern North Sea), covering approximately 0.5 m2 each. Ground truthing was done using underwater video data. Two stations were populated by tubeworm colonies of different population densities, and one station had a hydrodynamically rippled seafloor. Tubeworms caused an increased skewness of the microtopography height distribution and an increased root mean square roughness at short spatial wavelengths compared with hydrodynamic bedforms. Spectral analysis of the 2D Fourier transformed microtopography showed that the roughness magnitude increased at spatial wavelengths between 0.020 and 0.003 m independently of the tubeworm density. This effect was not detected by commonly used 1D roughness profiles but required consideration of the complete spectrum. Overall, the results reveal that new indicator variables for benthic organisms may be developed based on microtopographic data. An example demonstrates the use of local slope and skewness to detect tubeworms in the measured digital elevation model.

  3. Phytoplankton pigment concentrations in the Middle Atlantic Bight - Comparison of ship determinations and CZCS estimates. [Coastal Zone Color Scanner

    NASA Technical Reports Server (NTRS)

    Gordon, H. R.; Brown, J. W.; Clark, D. K.; Brown, O. B.; Evans, R. H.; Broenkow, W. W.

    1983-01-01

    The processing algorithms used for relating the apparent color of the ocean observed with the Coastal-Zone Color Scanner on Nimbus-7 to the concentration of phytoplankton pigments (principally the pigment responsible for photosynthesis, chlorophyll-a) are developed and discussed in detail. These algorithms are applied to the shelf and slope waters of the Middle Atlantic Bight and also to Sargasso Sea waters. In all, four images are examined, and the resulting pigment concentrations are compared to continuous measurements made along ship tracks. The results suggest that over the 0.08-1.5 mg/cu m range, the error in the retrieved pigment concentration is of the order of 30-40% for a variety of atmospheric turbidities. In three direct comparisons between ship-measured and satellite-retrieved values of the water-leaving radiance, the atmospheric correction algorithm retrieved the water-leaving radiance with an average error of about 10%. This atmospheric correction algorithm does not require any surface measurements for its application.

  4. Coupling of wave and circulation models in coastal-ocean predicting systems: a case study for the German Bight

    NASA Astrophysics Data System (ADS)

    Staneva, Joanna; Wahle, Kathrin; Günther, Heinz; Stanev, Emil

    2016-06-01

    This study addresses the impact of coupling between wave and circulation models on the quality of coastal ocean predicting systems. This is exemplified for the German Bight and its coastal area known as the Wadden Sea. The latter is the area between the barrier islands and the coast. This topic reflects the increased interest in operational oceanography to reduce prediction errors of state estimates at coastal scales, which in many cases are due to unresolved non-linear feedback between strong currents and wind waves. In this study we present analysis of wave and hydrographic observations, as well as results of numerical simulations. A nested-grid modelling system is used to produce reliable nowcasts and short-term forecasts of ocean state variables, including waves and hydrodynamics. The database includes ADCP observations and continuous measurements from data stations. The individual and combined effects of wind, waves and tidal forcing are quantified. The performance of the forecast system is illustrated for the cases of several extreme events. The combined role of wave effects on coastal circulation and sea level are investigated by considering the wave-dependent stress and wave breaking parameterization. Also the response, which the circulation exerts on the waves, is tested for the coastal areas. The improved skill of the coupled forecasts compared to the non-coupled ones, in particular during extreme events, justifies the further enhancements of coastal operational systems by including wave effects in circulation models.

  5. Seafloor monitoring west of Helgoland (German Bight, North Sea) using the acoustic ground discrimination system RoxAnn

    NASA Astrophysics Data System (ADS)

    Hass, H. Christian; Mielck, Finn; Fiorentino, Dario; Papenmeier, Svenja; Holler, Peter; Bartholomä, Alexander

    2017-04-01

    Marine habitats of shelf seas are in constant dynamic change and therefore need regular assessment particularly in areas of special interest. In this study, the single-beam acoustic ground discrimination system RoxAnn served to assess seafloor hardness and roughness, and combine these parameters into one variable expressed as RGB (red green blue) color code followed by k-means fuzzy cluster analysis (FCA). The data were collected at a monitoring site west of the island of Helgoland (German Bight, SE North Sea) in the course of four surveys between September 2011 and November 2014. The study area has complex characteristics varying from outcropping bedrock to sandy and muddy sectors with mostly gradual transitions. RoxAnn data enabled to discriminate all seafloor types that were suggested by ground-truth information (seafloor samples, video). The area appears to be quite stable overall; sediment import (including fluid mud) was detected only from the NW. Although hard substrates (boulders, bedrock) are clearly identified, the signal can be modified by inclination and biocover. Manually, six RoxAnn zones were identified; for the FCA, only three classes are suggested. The latter classification based on `hard' boundaries would suffice for stakeholder issues, but the former classification based on `soft' boundaries is preferred to meet state-of-the-art scientific objectives.

  6. Coupling of wave and circulation models in coastal-ocean predicting systems: a case study for the German Bight

    NASA Astrophysics Data System (ADS)

    Staneva, J.; Wahle, K.; Günther, H.; Stanev, E.

    2015-12-01

    This study addresses the impact of coupling between wind wave and circulation models on the quality of coastal ocean predicting systems. This is exemplified for the German Bight and its coastal area known as the Wadden Sea. The latter is the area between the barrier islands and the coast. This topic reflects the increased interest in operational oceanography to reduce prediction errors of state estimates at coastal scales, which in many cases are due to unresolved nonlinear feedback between strong tidal currents and wind-waves. In this study we present analysis of wave and hydrographic observations, as well as results of numerical simulations. A nested-grid modelling system is used to producing reliable nowcasts and short-term forecasts of ocean state variables, including wind waves and hydrodynamics. The data base includes ADCP observations and continuous measurements from data stations. The individual and collective role of wind, waves and tidal forcing are quantified. The performance of the forecast system is illustrated for the cases of several extreme events. Effects of ocean waves on coastal circulation and sea level are investigated by considering the wave-dependent stress and wave breaking parameterization. Also the effects which the circulation exerts on the wind waves are tested for the coastal areas using different parameterizations. The improved skill of the coupled forecasts compared to the non-coupled ones, in particular during extreme events, justifies the further enhancements of coastal operational systems by including wind wave models.

  7. Plan for study: response of the habitat and biota of the inner New York Bight to abatement of sewage sludge dumping. Technical memo

    SciTech Connect

    Not Available

    1988-06-01

    The purpose of this study was to document changes in living marine resources and their habitats during and following the period in which sewage sludge dumping is phased out at the 12-mile site. Choice of monitoring variables was based on two considerations: (1) relevance to fisheries of the inner Bight, both directly, in terms of abundance, distribution, and contamination of resource species and indirectly, as indicated by quality of their habitats, and (2) predictive value in detecting changes with abatement. Biological, chemical, and physical oceanographic approaches were integrated to provide comprehensive and statistically valid work plans.

  8. A study of sediment motions and bottom layer dynamics over the Middle Atlantic Bight shelf and upper slope. Final technical report, 1 June 1992--31 May 1995

    SciTech Connect

    Pietrafesa, L.J.

    1995-12-31

    A study of sediment dynamics over the Middle Atlantic Bight (MAB) in the vicinity of the Cape Hatteras Confluence (CHC), including the mouths of estuaries, the shelf and the slope, was carried out by investigators at North Carolina State University as part of the Department of Energy Ocean Margins Program. Studied were processes effecting sediment motion. In particular, the processes which determine rates of vertical transport of dissolved carbon dioxide and organic matter and particulates to and from the bottom by turbulent mixing resuspension and particulate sinking and vertical motions induced by BBL convergences; especially during periods of storm activity when both surface waves and currents are maxima.

  9. Seasonal advection of Pacific Equatorial Water alters oxygen and pH in the Southern California Bight

    NASA Astrophysics Data System (ADS)

    Takeshita, Y.; Frieder, C.; Nam, S.; Martz, T. R.

    2015-12-01

    Chemical properties of the California Undercurrent (CU) have been changing over the past several decades, yet the mechanisms responsible for the trend are still not fully understood. We present a survey of temperature, salinity, O2, pH, and currents at intermediate depths (defined here as 50-500 m) in the summer (June 30 to July 10) and winter (December 8 to 15) of 2012 in the southern region of the Southern California Bight. Observations of temperature, salinity, and currents reveal that local bathymetry and small gyres play an important role in the flow path of the California Undercurrent (CU). Using spiciness (π) as a tracer, we observe a 10% increase of Pacific Equatorial Water (PEW) in the core of the CU during the summer versus the winter. This is associated with an increase in π of 0.2, and a decrease in O2 and pH of 30 µmol kg-1 and 0.022, respectively; the change in pH is driven by increased CO2, while total alkalinity remains unchanged. The high-π, low-O2, low-pH waters during the summer are not distributed uniformly in the study region. Moreover, mooring observations at the edge of the continental shelf reveal intermittent intrusions of PEW onto the shelf with concomitant decreases in O2 and pH. We estimate that increased advection of PEW in the CU could account for approximately 50% of the observed decrease in O2, and between 49 and 73% of the decrease in pH, over the past three decades.

  10. On the mass and salt budgets for a region of the continental shelf in the southern Mid-Atlantic Bight

    SciTech Connect

    Kim, Yoo Yin; Weatherly, Georges L.; Pietrafesa, Leonard J.

    2001-12-01

    Two field studies were conducted across and along the continental shelf, one from February to May 1996 (deployment 1) and the other from July to October 1996 (deployment 2), in part to determine the mass and salt budgets of shelf water from south of Cape Henry to north of Cape Hatteras, the southernmost portion of the Mid-Atlantic Bight. The temporal means of current meter records indicated that most of the water enters the region across its northern boundary near the shelf break as part of a southward, alongshore current and exits the southeast corner as a southeastward flowing current. Estimates of the volume transports indicated that not all the transport across the northern boundary was accounted for by transport across the southern boundary, and that the remainder occurred as a broad, diffusive flow across the eastern boundary at the shelf break. Time series of volume transport across northern and southern boundaries were very similar and associated with variations in the alongshore wind stress and sea level, indicative of a geostrophic balance. Examination of the individual current meter records indicated these fluctuations were very barotropic even during deployment 2, which included the stratified summer season. Time series of the volume transport across the eastern boundary at the shelf break strongly mirrored the volume transport across the northern boundary minus that across the southern boundary, suggesting that the inferred eastern boundary transport was real and accommodated whatever the southern boundary could not. The turbulent salt flux across each boundary contributes very little to the net respective mass fluxes because the salt fluxes are almost governed by current velocity fields. The instantaneous and mean salt fluxes across each boundary were very well approximated by the instantaneous and mean volume transports across the boundary times the deployment average salinity across that boundary, respectively. The Ocean Margins Program (OMP) moored

  11. Mapping and Monitoring of Dynamic Seafloor Features with Hydroacoustic Devices in Sandy Coastal Areas (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Papenmeier, S.; Mielck, F.; Hass, H. C.

    2014-12-01

    In order to understand marine ecosystems and to provide basic data for a sustainable management in these vulnerable areas, seafloor mapping has become increasingly important. Since the knowledge regarding the seabed environments and their dynamics are still sparse, new mapping techniques have evolved in the last years and hydroacoustic devices became an important tool for quick and reliable mapping. In 2007 we started a monitoring program in the German Bight (North Sea) using sidescan sonar (Imagenex YellowFin, 330 kHz) in a study site comprising approximately 1,500 km2. In subsequent years, the area was mapped repeatedly with a resolution of ~25 cm. For ground truthing, several hundred sediment samples were taken. The investigations reveal that the area is mainly characterized by fine to coarse sand which is arranged in different seafloor features such as subaquatic dunes or relicts of Pleistocene moraines. While the alignment and position of the moraines was stable throughout the years, the dunes can be highly dynamic. Their migration indicates the amount of sediment transport in these areas. Some seafloor features could be identified as so-called sorted bedforms, which are spatially-grain-size-sorted patterns on the seafloor consisting of small rippled medium sand surrounded by smooth fine sand. These flow-transverse features are morphological linked to ridges and depressions and are further maintained by ebb and flood currents of almost equal strengths. The medium sand is separated from the fine sand by sharp boundaries in all directions which were generated by the bidirectional flow field. The extend and alignment of the sorted bedforms seem to be relatively stable in a time frame of 6 years, however small-scale variabilities up to serveral meters could be detected. We suppose that these processes mainly occur during storm surges while the fine-sand layers are winnowed away and hence the shapes of the bedforms changes.

  12. Assessing the effect of nutrient mitigation measures in the watersheds of the Southern Bight of the North Sea.

    PubMed

    Thieu, Vincent; Garnier, Josette; Billen, Gilles

    2010-02-15

    The Seine, Somme, and Scheldt Rivers (France, Belgium, and Netherlands) are the major delivering rivers flowing into the continental coastal zone of the Southern Bight of the North Sea, an area regularly affected by eutrophication problems. In the present work, the Seneque-Riverstrahler model was implemented in a multi-regional case study in order to test several planned mitigation measures aimed at limiting stream nutrient contamination and restoring balanced nutrient ratios at the coastal zone. This modeling approach, which is spatially distributed at the basin scale, allows assessing the impact of any change in human activities, which widely differ over the three basins. Here, we define realistic scenarios based on currently proposed measures to reduce point and non-point sources, such as the upgrading of wastewater treatment, the introduction of catch crops, and the development of extensive farming. An analysis of the current situation showed that a 47-72% reduction in P point-source emissions within the three basins could be reached if the intended P treatment was generalized to the largest treatment plants. However, only an overall 14-23% reduction in N could be achieved at the outlet of the three basins, by combining improved wastewater treatment and land use with management measures aimed at regulating agricultural practices. Nonetheless, in spite of these efforts, N will still be exported in large excess with respect to the equilibrium defined by the Redfield ratios, even in the most optimistic hypothesis describing the long-term response of groundwater nitrate concentrations. A comprehensive assessment of these mitigation measures supports the need for additional reductions of nutrient losses from agriculture to control harmful algae development. It also stresses the relevance of this mechanistic approach, in which nutrient transfers from land to sea can be calculated, as an integrated strategy to test policy recommendations.

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

    USGS Publications Warehouse

    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.

  14. Diel Vertical Dynamics of Gelatinous Zooplankton (Cnidaria, Ctenophora and Thaliacea) in a Subtropical Stratified Ecosystem (South Brazilian Bight)

    PubMed Central

    Nogueira Júnior, Miodeli; Brandini, Frederico Pereira; Codina, Juan Carlos Ugaz

    2015-01-01

    The diel vertical dynamics of gelatinous zooplankton in physically stratified conditions over the 100-m isobath (~110 km offshore) in the South Brazilian Bight (26°45’S; 47°33’W) and the relationship to hydrography and food availability were analyzed by sampling every six hours over two consecutive days. Zooplankton samples were taken in three depth strata, following the vertical structure of the water column, with cold waters between 17 and 13.1°C, influenced by the South Atlantic Central Water (SACW) in the lower layer (>70 m); warm (>20°C) Tropical Water in the upper 40 m; and an intermediate thermocline with a deep chlorophyll-a maximum layer (0.3–0.6 mg m-3). Two distinct general patterns were observed, emphasizing the role of (i) physical and (ii) biological processes: (i) a strong influence of the vertical stratification, with most zooplankton absent or little abundant in the lower layer. The influence of the cold SACW on the bottom layer apparently restricted the vertical occupation of most species, which typically inhabit epipelagic warm waters. Even among migratory species, only a few (Aglaura hemistoma, Abylopsis tetragona eudoxids, Beroe sp., Thalia democratica, Salpa fusiformis) crossed the thermocline and reached the bottom layer. (ii) A general tendency of partial migrations, with variable intensity depending on the different species and developmental stages; populations tended to be more widely distributed through the water column during daylight, and to become more aggregated in the upper layer during the night, which can be explained based on the idea of the “hunger-satiation hypothesis”, maximizing feeding and minimizing the chances of being predated. PMID:26637179

  15. Modeling larval connectivity of the Atlantic surfclams within the Middle Atlantic Bight: Model development, larval dispersal and metapopulation connectivity

    NASA Astrophysics Data System (ADS)

    Zhang, Xinzhong; Haidvogel, Dale; Munroe, Daphne; Powell, Eric N.; Klinck, John; Mann, Roger; Castruccio, Frederic S.

    2015-02-01

    To study the primary larval transport pathways and inter-population connectivity patterns of the Atlantic surfclam, Spisula solidissima, a coupled modeling system combining a physical circulation model of the Middle Atlantic Bight (MAB), Georges Bank (GBK) and the Gulf of Maine (GoM), and an individual-based surfclam larval model was implemented, validated and applied. Model validation shows that the model can reproduce the observed physical circulation patterns and surface and bottom water temperature, and recreates the observed distributions of surfclam larvae during upwelling and downwelling events. The model results show a typical along-shore connectivity pattern from the northeast to the southwest among the surfclam populations distributed from Georges Bank west and south along the MAB shelf. Continuous surfclam larval input into regions off Delmarva (DMV) and New Jersey (NJ) suggests that insufficient larval supply is unlikely to be the factor causing the failure of the population to recover after the observed decline of the surfclam populations in DMV and NJ from 1997 to 2005. The GBK surfclam population is relatively more isolated than populations to the west and south in the MAB; model results suggest substantial inter-population connectivity from southern New England to the Delmarva region. Simulated surfclam larvae generally drift for over one hundred kilometers along the shelf, but the distance traveled is highly variable in space and over time. Surfclam larval growth and transport are strongly impacted by the physical environment. This suggests the need to further examine how the interaction between environment, behavior, and physiology affects inter-population connectivity. Larval vertical swimming and sinking behaviors have a significant net effect of increasing larval drifting distances when compared with a purely passive model, confirming the need to include larval behavior.

  16. Diel Vertical Dynamics of Gelatinous Zooplankton (Cnidaria, Ctenophora and Thaliacea) in a Subtropical Stratified Ecosystem (South Brazilian Bight).

    PubMed

    Nogueira Júnior, Miodeli; Brandini, Frederico Pereira; Codina, Juan Carlos Ugaz

    2015-01-01

    The diel vertical dynamics of gelatinous zooplankton in physically stratified conditions over the 100-m isobath (~110 km offshore) in the South Brazilian Bight (26°45'S; 47°33'W) and the relationship to hydrography and food availability were analyzed by sampling every six hours over two consecutive days. Zooplankton samples were taken in three depth strata, following the vertical structure of the water column, with cold waters between 17 and 13.1°C, influenced by the South Atlantic Central Water (SACW) in the lower layer (>70 m); warm (>20°C) Tropical Water in the upper 40 m; and an intermediate thermocline with a deep chlorophyll-a maximum layer (0.3-0.6 mg m-3). Two distinct general patterns were observed, emphasizing the role of (i) physical and (ii) biological processes: (i) a strong influence of the vertical stratification, with most zooplankton absent or little abundant in the lower layer. The influence of the cold SACW on the bottom layer apparently restricted the vertical occupation of most species, which typically inhabit epipelagic warm waters. Even among migratory species, only a few (Aglaura hemistoma, Abylopsis tetragona eudoxids, Beroe sp., Thalia democratica, Salpa fusiformis) crossed the thermocline and reached the bottom layer. (ii) A general tendency of partial migrations, with variable intensity depending on the different species and developmental stages; populations tended to be more widely distributed through the water column during daylight, and to become more aggregated in the upper layer during the night, which can be explained based on the idea of the "hunger-satiation hypothesis", maximizing feeding and minimizing the chances of being predated.

  17. Analysis of phytoplankton distribution and community structure in the German Bight with respect to the different size classes

    NASA Astrophysics Data System (ADS)

    Wollschläger, Jochen; Wiltshire, Karen Helen; Petersen, Wilhelm; Metfies, Katja

    2015-05-01

    Investigation of phytoplankton biodiversity, ecology, and biogeography is crucial for understanding marine ecosystems. Research is often carried out on the basis of microscopic observations, but due to the limitations of this approach regarding detection and identification of picophytoplankton (0.2-2 μm) and nanophytoplankton (2-20 μm), these investigations are mainly focused on the microphytoplankton (20-200 μm). In the last decades, various methods based on optical and molecular biological approaches have evolved which enable a more rapid and convenient analysis of phytoplankton samples and a more detailed assessment of small phytoplankton. In this study, a selection of these methods (in situ fluorescence, flow cytometry, genetic fingerprinting, and DNA microarray) was placed in complement to light microscopy and HPLC-based pigment analysis to investigate both biomass distribution and community structure of phytoplankton. As far as possible, the size classes were analyzed separately. Investigations were carried out on six cruises in the German Bight in 2010 and 2011 to analyze both spatial and seasonal variability. Microphytoplankton was identified as the major contributor to biomass in all seasons, followed by the nanophytoplankton. Generally, biomass distribution was patchy, but the overall contribution of small phytoplankton was higher in offshore areas and also in areas exhibiting higher turbidity. Regarding temporal development of the community, differences between the small phytoplankton community and the microphytoplankton were found. The latter exhibited a seasonal pattern regarding number of taxa present, alpha- and beta-diversity, and community structure, while for the nano- and especially the picophytoplankton, a general shift in the community between both years was observable without seasonality. Although the reason for this shift remains unclear, the results imply a different response of large and small phytoplankton to environmental influences.

  18. Persistence and transport of fauna on drifting kelp (Macrocystis pyrifera (L.) C. Agardh) rafts in the Southern California Bight.

    PubMed

    Hobday

    2000-10-05

    Drifting rafts of Macrocystis pyrifera may connect isolated kelp forests in the Southern California Bight. To determine which species might utilize this dispersal mechanism, faunal samples from natural drifting rafts and attached M. pyrifera plants were collected during five cruises between March 1995 and December 1997. These rafts, which can be considered as floating islands, were aged and the macroinvertebrate assemblage enumerated. There was no significant relationship between raft age and species richness, or between species richness and distance offshore, which contrasts with predictions based on island biogeography. Species richness, however, was related to raft weight. Patterns of species presence and density were investigated relative to raft age for the species most frequently associated with rafts. Only one species, the isopod Idotea resecata, was found on all sampled rafts. Some species increased in frequency with raft age and others decreased, but only one relationship, a decline in the frequency of the anemone Epiactis prolifera with raft age was significant. When species density was examined over all cruises, only I. resecata had a significant change in density (an increase) with raft age, but additional significant relationships were found when species density patterns were considered by cruise. The results of all the tests were combined to provide a measure of "raft success". Nine of the most frequent 19 species had a positive score, indicating a favorable response to rafting, seven were unaffected, and two species had negative responses to rafting. Extinction times were calculated using species abundance and raft age relationships. Two species (E. prolifera and Paracerceis cordata), were predicted to persist on rafts for only about 100 days, which is the maximum estimated raft lifetime. All other species were predicted to persist for longer periods if the rafts floated longer. Kelp fauna that begin rafting appear to be largely unaffected by rafting

  19. USE OF δ13C, δ15N AND CARBON TO NITROGEN RATIOS TO EVALUATE THE IMPACT OF SEWAGE DERIVED PARTICULATE ORGANIC MATTER ON THE BENTHIC COMMUNITIES OF THE SOUTHERN CALIFORNIA BIGHT

    EPA Science Inventory

    We present stable isotope (δ13C and δ15N) measurements of particulate organic matter (POM) sources and benthic organic matter (OM) compartments, and sediment C/N ratios from the coastal area of the southern end of the Southern California Bight (SCB). We use ...

  20. Continental shelf processes affecting the oceanography of the South Atlantic Bight: Progress report, June 1, 1987 to May 31, 1988. [FLEX

    SciTech Connect

    Atkinson, L.P.

    1988-01-01

    This study of continental shelf processes affecting the oceanography of the South Atlantic Bight (SAB) is part of the interdisciplinary DOE-sponsored South Atlantic Bight Program. Our part of the program involves hydrographic and nutrient characteristics of the region. Current research efforts in the SAB Program are being focused on the inner shelf region where effects of bottom friction, local wind forcing, river and estuarine discharge, and tides, which are all small scale processes, are important. Our major accomplishment during the past year was the completion of the FLEX (Fall Experiment) field study. Since most of our data collection is computerized, preliminary hydrographic data analysis was done on board ship during the cruise and preliminary results are available. These results will be presented in this report. We are just beginning our standard data processing and data analysis procedures. We continued the processing and analysis of SPREX data collected during April 1985. Work has also continued on the older GABEX I and II data sets. 8 refs., 19 figs., 2 tabs.

  1. The barred grunt Conodon nobilis (Perciformes: Haemulidae) in shallow areas of a tropical bight: spatial and temporal distribution, body growth and diet

    NASA Astrophysics Data System (ADS)

    Pombo, Maíra; Denadai, Márcia Regina; Bessa, Eduardo; Santos, Flávia Borges; de Faria, Vanessa Hermann; Turra, Alexander

    2014-06-01

    This study aimed to comprehensively investigate the population biology of Conodon nobilis (Perciformes, Haemulidae) in Caraguatatuba Bight, southeastern Brazil. Monthly trawls were performed from October 2003 through October 2004 in two areas of the bight that are similar to but distant from each other, South and North. For all specimens, the size was measured and the sex and reproductive stage identified. Abundance and size were compared over areas and months. Body growth parameters were parameterized according to the Von Bertalanffy growth function. The stomach contents were identified and quantified. C. nobilis occurred mainly in the North area and showed an erratic pattern of abundance over time. Several cohorts entered in different periods, but very few large and mature individuals were observed. The results indicate a preference for shallow, ocean-influenced habitats and some degree of segregation between young and older individuals. The species showed a distribution consistent with an r-strategist species, with high abundance and a high growth constant ( K = 0.68 year-1 and L max = 34.2 cm). Both the relative length of the digestive tube and the prey items indicated a carnivorous feeding habit; mysids were the main item of the diet throughout the study period, indicating that this grunt is a specialist feeder. Other frequently observed items were amphipods and fish fragments. Ingestion of scales is possibly intentional.

  2. Comparison of antibodies in marine fish from clean and polluted waters of the New York Bight: relative levels against 36 bacteria.

    PubMed Central

    Robohm, R A; Brown, C; Murchelano, R A

    1979-01-01

    Fish from polluted waters are subject to increased prevalence of disease. Because they respond to bacterial pathogens by producing serum antibodies, it was possible to construct a seasonal serological record in three fish species from clean and polluted waters of the New York Bight. Antibody levels were determined by testing sera for agglutinating activity against 36 strains of bacteria. Evaluation of 5,100 antibody titrations showed the following. During warm months, summer flounder (Paralichthys dentatus) from the polluted area had significantly higher antibody levels and antibody to a greater diversity of bacteria than fish from the unpolluted area. Weakfish (Cynoscion regalis) from the same polluted area shared with summer flounder raised titers to many bacteria. The greatest proportion of raised titers was against Vibrio species, although prominent titers were also seen against Aeromonas salmonicida and Haemophilus piscium, bacteria usually associated with diseases in freshwater but not marine fish. Differences between polluted and clean waters were not as evident in winter flounder (Pseudopleuronectes americanus) during cold months. This could be due, in part, to reduced antibody production at colder temperatures. The data illustrate the usefulness of the serum antibody record in identifying environmental exposure to bacteria in marine fish and indicate that the polluted New York Bight apex has increased levels and diversity of bacteria during warm months. PMID:518084

  3. The winter distribution of nutrients in the Southern Bight of the North Sea (1961-1978) and in the estuaries of the scheldt and the rhine/meuse

    NASA Astrophysics Data System (ADS)

    van Bennekom, A. J.; Wetsteijn, F. J.

    In many years the winter distribution of nutrients in the eastern part of the Southern Bight is influenced by phytoplankton growth, always in February, sometimes in January but not in January 1961 and 1978, months with a relatively low insolation and high wind strength. The Scheldt river has higher nutrient concentrations than the rivers Rhine and Seine. The waters of the Scheldt river plume are distinguished from those of the Seine and the Rhine/Meuse with dissolved silica as a tracer. The extension of the Scheldt river plume is related to wind direction. The increase of inorganic nutrients from January 1961 to January 1978 in the northern part of the Southern Bight is related to the increase in the river Rhine. The increase in the Strait of Dover is related to discharges from the river Seine and the English coast. Only data outside the Scheldt river plume were selected for the comparison. An increase of nutrient concentrations is measurable over the entire salinity range and is largest for phosphate (up to 3 times at low salinities), less for nitrate (about 1.5 times for all salinities) and hardly noticeable for silicic acid. Nitrate extrapolation to low salinity agrees with upstream river values, but phosphate extrapolation gives higher concentrations, probably due to discharges of phosphogypsum in estuaries.

  4. Organic storage of CO 2 on the continental slope off the mid-Atlantic bight, the southeastern Bering Sea, and the Peru coast

    NASA Astrophysics Data System (ADS)

    Walsh, John J.; Premuzic, Eugene T.; Gaffney, Jeffrey S.; Rowe, Gilbert T.; Harbottle, Garman; Stoenner, Raymond W.; Balsam, William L.; Betzer, Peter R.; Macko, Steven A.

    1985-07-01

    A comparison is made of organic content, sedimentation rates derived from 14C and 210Pb analyses, 13C and 15N isotope ratios, amorphous silica, particle size, and calcium carbonate within sediments from slopes off the mid-Atlantic bight, the southeastern Bering Sea, and the Peru coast. These sediments are mainly marine, diatom-rich, and about one-third of the organic carbon is recent, reflecting a possible transient of shelf export in response to man's increased activities since the industrial revolution. Using a combination of sedimentation and mixing rates of carbon, the C:N ratio of sediments within the upper 50 cm, and the amount of nitrogen thought to be released from the coastal zone, independent estimates suggest a carbon loading to world slopes of ˜0.3 to 0.5 × 10 9 tons C y -1. The Bering slope exhibits no anthropogenic transients, however, while increased carbon loading may have occurred off Peru in response to overfishing and off the mid-Atlantic bight in response to eutrophication. The generality of our results depends on which of the three systems is most representative of world slopes.

  5. Joint Geophysical and Hydrologic Constraints on Shallow Groundwater Flow Systems in Clastic Salt Marshes of the South Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Ruppel, C.; Fulton, P.; Schultz, G. M.; Castillo, L.; Bartlett, J.; Sibley, S.

    2005-12-01

    Salt marsh systems play a critical role in buffering upland coastal areas from the influence of open saltwater bodies and in filtering contaminants that originate offshore or are flushed from uplands. For these reasons, it is important to understand the salt marsh hydrologic cycle, especially the interaction of groundwater and surface water across low-lying coastal fringes and the changes in physical, chemical, and ecological parameters across salinity gradients extending from upland to tidal creek to open water. For the past 5 years, we have conducted hydrogeophysical surveys (inductive EM and DC resistivity) and collected limited, coincident groundwater hydrologic data in clastic salt marshes throughout the South Atlantic Bight (SAB), stretching from South Carolina on the north to the Georgia-Florida border on the south. All of the marshes are dominated by Spartina and Juncus grasses and are cut by tidally-influenced creeks, but both the lithology and age of the marshes vary widely. For example, one highly homogeneous marsh study site has formed only within the past century, while most sites have existed for thousands of years and have laterally and vertically heterogeneous lithology. Geophysical images of the marsh subsurface and coincident monitoring of groundwater temperature, water level, and/or chemistry consistently show that marshes in the mixed energy environment of the middle part of the SAB (GCE LTER) tend to be dominated by submarsh discharge of freshwater to adjacent tidal creeks. In the South Carolina part of the SAB, we have greater evidence for seepage, particularly through biologically-created macropore networks and permeable sediment bodies that intersect tidal creeks. It is possible though that the South Carolina results are not so much 'universal' as reflective of local lithology. In a very young marsh near the Florida border, geophysical imaging implies a mixture of seepage and submarsh flow, and hydrologic data provide unequivocal proof that

  6. Ecomorphodynamic feedbacks and barrier island response to disturbance: Insights from the Virginia Barrier Islands, Mid-Atlantic Bight, USA

    NASA Astrophysics Data System (ADS)

    Wolner, Catherine W. V.; Moore, Laura J.; Young, Donald R.; Brantley, Steven T.; Bissett, Spencer N.; McBride, Randolph A.

    2013-10-01

    Ecomorphodynamic feedbacks play an important role in the susceptibility and response of barrier islands to disturbance by overwash. Dune-building grasses, like Ammophila breviligulata, can help to restore areas of high relief after overwash events (i.e., resist disturbance). If overwash recurs before dunes have reestablished, however, overwash-adapted "maintainer" species, like Spartina patens (upright variety), may preferentially survive. Maintainer species help to preserve low, flat topography, thereby increasing the likelihood of future overwash (i.e., reinforcing disturbance). Under frequent disturbance conditions, this positive feedback may lead to overwash persistence. We explore the potential influence of the maintainer feedback on two morphologically distinct barrier islands in the Virginia Coast Reserve (VCR), located in the Mid-Atlantic Bight of the U.S. East Coast. Combined topographic and vegetation surveys show that on Hog Island (high-relief, rotating), where dunes dominated by A. breviligulata are ubiquitous, overwash zones are currently limited in extent and related to beach width rather than dominance by S. patens. Historical aerial photos and stratigraphic evidence (ground-penetrating radar, cores) indicate that gradual recovery has taken place following overwash events on Hog Island, except where the beach is narrow and eroding. Conversely, on Metompkin Island (low-relief, transgressing), overwash is widespread and dominated by S. patens, particularly along the rapidly migrating northern half of the island, where shell armoring is also common. Overwash has generally been more prevalent and persistent here than on Hog Island. We present a new conceptual model of the response of barrier islands to disturbance incorporating ecological and physical processes. Our findings suggest that in barrier systems where both dune-building grasses and overwash-adapted maintainer species are common (like the VCR), the maintainer feedback is likely to be a more

  7. Seasonal patterns of winter flounder Pseudopleuronectes americanus abundance and reproductive condition on the New York Bight continental shelf.

    PubMed

    Wuenschel, M J; Able, K W; Byrne, D

    2009-05-01

    To resolve varied and sometimes conflicting accounts of spawning and habitat characteristics for winter flounder Pseudopleuronectes americanus, seasonal patterns in abundance and reproductive condition were investigated in the New York Bight, near the southern edge of their current reproductive range. Fish were collected from trawl surveys on the inner continental shelf from October 2006 to October 2007. Pseudopleuronectes americanus were most abundant during January and April surveys, were rarely collected in August, with intermediate abundances in June and October. Measurements of fish condition [hepato-somatic index (I(H)), condition factor (K) and the per cent dry mass of muscle tissue (%M(D))] and reproductive condition [gonado-somatic index (I(G))] were determined to evaluate seasonal changes in energy accumulation and depletion and reproduction. Males and females had similar patterns in body and reproductive condition, although the magnitude of change was greater for females. I(H) values were highest during spring and early summer, suggesting increased feeding following spawning. K and %M(D) increased through spring and summer then declined in the autumn and winter concurrent with gonadal development. Gonads began developing in the autumn, and in January, I(G) values approached spawning levels, with many spent individuals collected in spring. Within these general patterns, however, there was a large degree of variability among individuals, and a few mature non-reproductive ('skipped spawning') females were observed. In the period after spawning, increased energy intake, indicated by increased I(H), may influence reproductive output since this energy is gradually transferred to the muscle and used for gonadal development in the forthcoming year. The occurrence of ripening individuals on the inner continental shelf in January suggests that these fish either rapidly move into estuaries to spawn by February-March or they remain on the inner shelf to spawn, or

  8. Temporal and spatial patterns in wind stress and wind stress curl over the central Southern California Bight

    USGS Publications Warehouse

    Noble, Marlene A.; Rosenberger, Kurt J.; Rosenfeld, Leslie K.; Robertson, George L.

    2012-01-01

    In 2001, the U.S. Geological Survey, together with several other federal and municipal agencies, began a series of field programs to determine along and cross-shelf transport patterns over the continental shelves in the central Southern California Bight. As a part of these programs, moorings that monitor winds were deployed off the Palos Verdes peninsula and within San Pedro Bay for six 3–4 month summer and winter periods between 2001 and 2008. In addition, nearly continuous records of winds for this 7-year period were obtained from a terrestrial site at the coast and from a basin site offshore of the long-term coastal site. The mean annual winds are downcoast at all sites. The alongshelf components of wind stress, which are the largest part of the low-frequency wind stress fields, are well correlated between basin, shelf and coastal sites. On average, the amplitude of alongshelf fluctuations in wind stress are 3–4 times larger over the offshore basin, compared to the coastal site, irrespective of whether the fluctuations represent the total, or just the correlated portion of the wind stress field. The curl in the large-scale wind stress tends to be positive, especially in the winter season when the mean wind stress is downcoast and larger at the offshore basin site than at the beach. However, since the fluctuation in wind stress amplitudes are usually larger than the mean, periods of weak negative curl do occur, especially in the summer season when the largest normalized differences in the amplitude of wind stress fluctuations are found in the nearshore region of the coastal ocean. Even though the low-frequency wind stress field is well-correlated over the continental shelf and offshore basins, out to distances of 35 km or more from the coast, winds even 10 km inshore of the beach do not represent the coastal wind field, at least in the summer months. The seasonal changes in the spatial structures in wind stress amplitudes suggest that an assessment of the

  9. The Paternal Landscape along the Bight of Benin – Testing Regional Representativeness of West-African Population Samples Using Y-Chromosomal Markers

    PubMed Central

    Larmuseau, Maarten H. D.; Vessi, Andrea; Jobling, Mark A.; Van Geystelen, Anneleen; Primativo, Giuseppina; Biondi, Gianfranco; Martínez-Labarga, Cristina; Ottoni, Claudio; Decorte, Ronny; Rickards, Olga

    2015-01-01

    Patterns of genetic variation in human populations across the African continent are still not well studied in comparison with Eurasia and America, despite the high genetic and cultural diversity among African populations. In population and forensic genetic studies a single sample is often used to represent a complete African region. In such a scenario, inappropriate sampling strategies and/or the use of local, isolated populations may bias interpretations and pose questions of representativeness at a macrogeographic-scale. The non-recombining region of the Y-chromosome (NRY) has great potential to reveal the regional representation of a sample due to its powerful phylogeographic information content. An area poorly characterized for Y-chromosomal data is the West-African region along the Bight of Benin, despite its important history in the trans-Atlantic slave trade and its large number of ethnic groups, languages and lifestyles. In this study, Y-chromosomal haplotypes from four Beninese populations were determined and a global meta-analysis with available Y-SNP and Y-STR data from populations along the Bight of Benin and surrounding areas was performed. A thorough methodology was developed allowing comparison of population samples using Y-chromosomal lineage data based on different Y-SNP panels and phylogenies. Geographic proximity turned out to be the best predictor of genetic affinity between populations along the Bight of Benin. Nevertheless, based on Y-chromosomal data from the literature two population samples differed strongly from others from the same or neighbouring areas and are not regionally representative within large-scale studies. Furthermore, the analysis of the HapMap sample YRI of a Yoruban population from South-western Nigeria based on Y-SNPs and Y-STR data showed for the first time its regional representativeness, a result which is important for standard population and forensic genetic applications using the YRI sample. Therefore, the uniquely

  10. Ethoxyresorufin O-deethylase (EROD) activity in the liver of dab (Limanda limanda L.) and flounder (Platichthys flesus L.) from the German Bight. EROD expression and tissue contamination

    NASA Astrophysics Data System (ADS)

    Westernhagen, H. v.; Krüner, G.; Broeg, K.

    1999-12-01

    Ethoxyresorufin O-deethylase (EROD) activity was measured in the liver of dab (Limanda limanda) and flounder (Platichthys flesus) from the German Bight (southern North Sea) and compared with muscle and liver polychlorinated biphenyl (PCB) concentrations in an attempt to relate EROD activity to PCB body burden. In none of the different datasets (species-, tissue- or matrix-dependent) was a significant (P<0.05) correlation between PCB tissue contamination and EROD activity found. Yet EROD activity was significantly correlated with polycyclic aromatic hydrocarbons (PAH) levels (phenanthrene, fluoranthene, pyrene) in muscle tissue, indicating a possible dependence of EROD expression on other ubiquitous organic contaminants, thus making it a suitable biomarker for general pollution.

  11. Sea floor cycling of organic matter in the continental margin of the mid-Atlantic Bight. Final report, May 1, 1995--April 30, 1998

    SciTech Connect

    Jahnke, R.A.

    1998-12-31

    The objective of this project was to examine quantitatively the cycling of organic matter at the sea floor of the mid-Atlantic Bight continental margin. This information would be used to better understand sedimentary geochemical processes and, when used in conjunction with other measurements made within the DOE Ocean Margins Program, would be used to constrain the offshore and surface-to-deep water transport of organic carbon in this region. The latter information is critical in assessing the role of continental margins in the sequestration of anthropogenic carbon dioxide, the dominant greenhouse gas, in the deep ocean. Because the build-up of greenhouse gases in the atmosphere may cause significant changes in climate, this project had major societal importance.

  12. Biogeochemical and Optical Analysis of Coastal DOM for Satellite Retrieval of Terrigenous DOM in the U.S. Middle Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Mannino, A.; Dyda, R. Y.; Hernes, P. J.; Hooker, Stan; Hyde, Kim; Novak, Mike

    2012-01-01

    Estuaries and coastal ocean waters experience a high degree of variability in the composition and concentration of particulate and dissolved organic matter (DOM) as a consequence of riverine/estuarine fluxes of terrigenous DOM, sediments, detritus and nutrients into coastal waters and associated phytoplankton blooms. Our approach integrates biogeochemical measurements (elemental content, molecular analyses), optical properties (absorption) and remote sensing to examine terrestrial DOM contributions into the U.S. Middle Atlantic Bight (MAB). We measured lignin phenol composition, DOC and CDOM absorption within the Chesapeake and Delaware Bay mouths, plumes and adjacent coastal ocean waters to derive empirical relationships between CDOM and biogeochemical measurements for satellite remote sensing application. Lignin ranged from 0.03 to 6.6 ug/L between estuarine and outer shelf waters. Our results demonstrate that satellite-derived CDOM is useful as a tracer of terrigenous DOM in the coastal ocean

  13. Defining habitats suitable for larval fish in the German Bight (southern North Sea): An IBM approach using spatially- and temporally-resolved, size-structured prey fields

    NASA Astrophysics Data System (ADS)

    Kühn, Wilfried; Peck, Myron A.; Hinrichsen, Hans-Harald; Daewel, Ute; Moll, Andreas; Pohlmann, Thomas; Stegert, Christoph; Tamm, Susanne

    2008-11-01

    We employed a coupled biological-physical, individual-based model (IBM) to estimate spatial and temporal changes in larval fish habitat suitability (the potential for areas to support survival and high rates of growth) of the German Bight, southern North Sea. In this Lagrangian approach, larvae were released into a size-structured prey field that was constructed from in situ measurements of the abundance and prosome lengths of stages of three copepods ( Acartia spp., Temora longicornis, Pseudocalanus elongatus) collected on a station grid repeatedly sampled from February to October 2004. The choice of prey species and the model parameterisations for larval fish foraging and growth were based on field data collected for sprat ( Sprattus sprattus) and other clupeid larvae. A series of 10-day simulations were conducted using 20 release locations to quantify spatial-temporal differences in projected larval sprat growth rates (mm d - 1) for mid-April, mid-May and mid-June 2004. Based upon an optimal foraging approach, modeled sprat growth rates agreed well with those measured in situ using larval fish ototliths. On the German GLOBEC station grid, our model predicted areas that were mostly unsuitable habitats (areas of low growth potential), e.g. north of the Frisian Islands, and others that were consistently suitable habitats (areas that had high growth potential), e.g. in the inner German Bight. In some instances, modelled larvae responded rapidly (~ 5 days) to changing environmental characteristics experienced along their drift trajectory, a result that appears reasonable given the dynamic nature of frontal regions such as our study area in the southern North Sea.

  14. Exchange of matter and energy between the Wadden Sea and the coastal waters of the German Bight-Estimations based on numerical simulations and field measurements

    NASA Astrophysics Data System (ADS)

    Dick, S.; Brockmann, U. H.; van Beusekom, J. E. E.; Fabiszisky, B.; George, M.; Hentschke, U.; Hesse, K.-J.; Mayer, B.; Nitz, Th.; Pohlmann, Th.; Poremba, K.; Schaumann, K.; Schönfeld, W.; Starke, A.; Tillmann, U.; Weide, G.

    1999-09-01

    Based on numerical simulations and high resolution measurements, budgets have been computed for transports of water and heat as well as dissolved and particulate matter between the coastal waters of the German Bight and the North Frisian Wadden Sea. p]During 3 measuring campaigns in summer, spring and winter, current conditions and water transports differed only slightly. In spite of different meteorological situations, inflow and outflow of North Sea water to and from the Wadden Sea were largely balanced. A net heat export from the North Frisian Wadden Sea was determined both in summer 1994 and spring 1995, i. e. the Wadden Sea represented a heat source for the adjacent North Sea waters. To compute transports of dissolved nutrients between the Wadden Sea and adjacent North Sea waters, in situ measurements were linked in different ways with the results of hydrodynamic-numerical models. The results of two independent methods show very good correspondence and definite seasonal differences for nitrate and phosphate. In spring and summer, nitrate input from the adjacent North Sea coastal waters into the Wadden Sea and phosphate export from the Wadden Sea into the German Bight was calculated. The exchange of silicate during spring and summer was within the scatter of silicate transports. In winter, an export of silicate from the Wadden Sea was observed. To compute suspended matter transports, the seston concentrations measured at anchor stations were multiplied by modelled water transports. During summer, input tendencies of particulate organic matter were computed. As a result of their horizontal gradients, some planktonic components (parts of phyto-, zoo-, myco and bacterioplankton) showed transport tendencies counter to the transport directions of total particulate organic matter.

  15. Mobile demersal megafauna at common offshore wind turbine foundations in the German Bight (North Sea) two years after deployment - increased production rate of Cancer pagurus.

    PubMed

    Krone, R; Dederer, G; Kanstinger, P; Krämer, P; Schneider, C; Schmalenbach, I

    2017-02-01

    Within the next decades the construction of thousands of different types of large wind turbine foundations in the North Sea will substantially increase the amount of habitat available to reef fauna. To gain first insights which effect these substantial changes in habitat structure and diversity might have on faunal stocks settling on hard substrata, we compared the mobile demersal megafauna associated with the common types of wind turbine foundations ('jacket', 'tripod' and 'monopile with scour protections of natural rock') in the southern German Bight, North Sea. Monopiles with scour protection were mostly colonized by typical reef fauna. They were inhabited by an average of about 5000 edible crabs Cancer pagurus (per foundation), which is more than twice as much as found at the foundation types without scour protection. Strong evidence was found that all three foundation types not only function as aggregation sites, but also as nursery grounds for C. pagurus. Assuming equal shares of the three foundation types in future wind farms, we project that about 27% of the local stock of C. pagurus might be produced on site. When, for example, comparing the existing fauna at 1000 ship wrecks and on the autochthonous soft substrate with those which probably will establish at the foundations of 5000 hypothetically realized wind turbines, it becomes clear that the German Bight in the future will provide new artificial reef habitats for another 320% crabs (C. pagurus) and 50% wrasse (Ctenolabrus rupestris) representing substrata-limited mobile demersal hard bottom species. Further research is urgently required in order to evaluate this overspill as it would be an important ecological effect of the recent offshore wind power development.

  16. Priceless prices and marine food webs: Long-term patterns of change and fishing impacts in the South Brazil Bight as reflected by the seafood market

    NASA Astrophysics Data System (ADS)

    Pincinato, R. B. M.; Gasalla, M. A.

    2010-10-01

    The lack of market variables in fishery systems (i.e., prices and quantities) has often been cited as one reason for the particular difficulty of understanding whole marine ecosystem change and its management under a broader ecosystem perspective. This paper shows the results of efforts to tackle this problem in the South Brazil Bight by compiling and analyzing in-depth an unprecedented 40-year database from the region’s largest wholesale seafood market, based in the megacity of São Paulo. Fishery landings and market values for the period 1968-2007 were analyzed primarily by updated trophic level classes and multispecies indicators including the (1) marine trophic index (MTI), (2) weighted price, and (3) log relative price index (LRPI) which relates prices and trophic levels. Moreover, an inferential analysis of major seafood category statistical trends in market prices and quantities and their positive and negative correlations was undertaken. In general, these market trends contributed substantially to identifying and clarifying the changes that occurred. Considerations of the behavior of demand, supply and markets are included. In particular, while the MTI did not support a “fishing down the marine food web” hypothesis, other indicators did show the continued scarcity of major high trophic level categories and fisheries target species. Overall, the results indicate that the analysis of fishery landings, or of certain other indicators alone, can mask real changes. Rather, a joint ecological-econometric analysis provides better evidence of the direction of ecosystem pressures and stock health. This method for detecting market changes across the food web may be particularly helpful for systems considered data-poor but where fish market data have been archived. This study further elucidates historical changes and fishing impacts in the South Brazil Bight ecosystem.

  17. Biological interactions and their role in community structure in the rocky intertidal of Helgoland (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Janke, Klaus

    1990-06-01

    Over 3 successive seasonal cycles (April 1986 to October 1988), field experiments were established within 3 intertidal levels in the sheltered rocky intertidal of Helgoland (North Sea, German Bight). Competitors for space ( Mytilus edulis, macroalgae), herbivores ( Littorina spp.) and predators ( Carcinus maenas) were either excluded from areas (0.25 m2) covered by undisturbed communities or enclosed at natural densities on areas that were cleared before of animals and plants. All the experimental fields (each 0.25 m2) were covered by cages with 4 mm gauze at the sides and a plexiglas top. The results of the experiments in the upper intertidal (occupied by Littorina spp. and Enteromorpha) showed that a natural density of herbivores could not prevent algal settlement and had only little influence on algal growth. Instead abiotic factors (storms, algae washed ashore) decreased the stock of the green algae. Experiments in the mid intertidal, dominated by Mytilus (50% cover), Fucus spp. (20%) and grazing L. littorea (100 ind. m-2) showed that community structure was directly changed both by grazing periwinkles and by competition for space between mussels and macroalgae. Whenever Littorina was excluded, the canopy of Fucus spp. increased continuously and reached total cover within two years. In addition to the increase of Fucus spp., the rock surface and the mussel shells were overgrown by Ulva pseudocurvata, which covered the experimental fields during parts of the summer in the absence of herbivores. As soon as perennial species (fucoids) covered most of the experimental areas, the seasonal growth of Ulva decreased drastically. Presence and growth of macroalgae were also controlled by serious competition for space with mussels. Established Mytilus prevented the growth of all perennial and ephemeral algae on the rocks. However, the shells of the mussels provided free space for a new settlement of Fucus and Ulva. In the lower intertidal (dominated by total algal cover

  18. Seismo-acoustic imaging of marine hard substrate habitats: a case study from the German Bight (SE North Sea)

    NASA Astrophysics Data System (ADS)

    Papenmeier, Svenja; Hass, H. Christian

    2016-04-01

    comparably small foot print which results in high spatial resolution (decimeter in the xyz directions) and hence allows a more precise demarcation of hard substrate areas. Data for this study were recorded in the "Sylt Outer Reef" (German Bight, North Sea) in May 2013 and March 2015. The investigated area is characterized by heterogeneously distributed moraine deposits and rippled coarse sediments partly draped with Holocene fine sands. The relict sediments and the rippled coarse sediments indicate both high backscatter intensities but can be distinguished by means of the hyperbola locations. The northeast of the study area is dominated by rippled coarse sediments (without hyperbolas) and the southwestern part by relict sediments with a high amount of stones represented by hyperbolas which is also proven by extensive ground-truthing (grab sampling and high quality underwater videos). An automated procedure to identify and export the hyperbola positions makes the demarcation of hard substrate grounds (here: relict sediments) reproducible, faster and less complex in comparison to the visual-manual identification on the basis of sidescan sonar data.

  19. Impact of internal and external Alkalinity fluxes on the carbonate system in the German Bight / SE North Sea - A model study for the years 2001 - 2009

    NASA Astrophysics Data System (ADS)

    Schwichtenberg, Fabian; Pätsch, Johannes; Amann, Thorben; Schartau, Markus; Thomas, Helmuth; Winde, Vera; Dellwig, Olaf; van Beusekom, Justus; Böttcher, Michael; Grashorn, Sebastian; Salt, Lesley

    2013-04-01

    Rising atmospheric CO2 concentrations may cause enhanced oceanic CO2 concentrations and thus ongoing acidification of the marine environment. Effects of acidification on the coastal ocean exhibit large variabilities due to shallow water column, tight benthic-pelagic coupling, nutrient cycling, and discharge from land. As a result of enhanced biogeochemical processes, seasonal pH variations in coastal and shelf regions can be up to an order of magnitude higher than in the open ocean and may potentially mask the decadal trend of decreasing pH. Total Alkalinity (TA) is an essential part of the carbonate system as it regulates the oceanic CO2 buffer capacity. Variations in TA are vital to understand observed pH variations. In the coastal zone variations in TA are particularly pronounced because of diverse external sources like river discharge, anaerobic degradation of organic material or methane fluxes in tidal flats in association with pore water exchange across the sediment-water interface. Beside these external fluxes TA also changes due to physical, chemical and biological processes. To better understand and quantify the effect of acidification in the southern North Sea as part of the northwest European Shelf we applied the ecosystem model ECOHAM with a prognostic treatment of TA. For the first step we included monthly varying TA and DIC concentrations of the main continental rivers draining to the North Sea. For the Dutch rivers we calculated these data from other parameters of the carbonate system (bicarbonate and pH) that have been measured in the respective estuaries. For the river Elbe we used data of TA and DIC concentrations that have been measured in the estuary. Simulation results reveal that the river contribution to TA flux is insufficient to explain the seasonal variations observed in the German Bight. As high summer concentrations remain unresolved in this model setup, elevated TA concentrations during summer in that area must originate from sources

  20. A Lagrangian Physical-Biological Model to Study Water Parcels Associated with Algal Blooms from Southern California Bight to Todos Santos Bay.

    NASA Astrophysics Data System (ADS)

    Vivas Téllez, I. E.; Rivas, D.

    2015-12-01

    Lagrangian ocean circulation and biological dynamics are numerically studied in Todos Santos Bay during the spring of 2007. This period is particularly interesting after an intense toxic algal bloom occurred in April 2007 in this area, which was associated with the wind-driven upwelling in the region. High resolution, numerical model simulations were carried out to study dynamical features along of the Southern California Bight (SCB), the coast of the northern Baja California (BC), and the interior of Todos Santos Bay (TSB). These simulations are used in a three-dimensional Lagrangian (particle tracking) analysis which provides information about the origin and distribution of the waters present in the Bay during the occurrence of the toxic bloom. After the selection of trajectories of particles showing coherent patterns, a Nitrate-Phytoplankton-Zooplankton-Detritus (NPZD) lower trophic model is implemented to study the influence of the environmental conditions that occur during the particle advection, solving the NPZD equations at every time-varying position of the advected particles. The model is also modified for phytoplankton growth as a function of the environmental temperature to somehow emulate the life cycle of Pseudo-nitzschia. The analysis of the trajectories shows that particles mainly come from two regions: from the north, in the southern portion of SCB and from regions west of the TSB. Knowing the regional circulation patterns and their phytoplankton dynamics can help to understand and even predict the origin and destination of the harmful algal blooms that occur in TSB and its surroundings.

  1. Parasites of flounder Platichthys flesus (L.) from the German Bight, North Sea, and their potential use in ecosystem monitoring. B. Community structure and fish parasite biodiversity

    NASA Astrophysics Data System (ADS)

    Schmidt, V.; Zander, S.; Körting, W.; Steinhagen, D.

    2003-10-01

    The analysis of fish-parasite community structure and the use of ecological richness and diversity measurements are commonly used for the evaluation of environmental stress in aquatic ecosystems. As part of an integrated biological-effect monitoring, the parasite community of flounder Platichthys flesus (L.) was investigated for various locations in the German Bight during spring and autumn of 1995-2000, using established ecological methods. Although the parasite-community composition was very similar at the component-community level, the number of component species as well as the species accumulation curves showed clear differences among the sites. On the infra-community level, all of the ecological measurements showed significantly lower values in flounder from the Elbe estuary, the most polluted site, than in flounder from Helgoland. This was seen during a single season or during both seasons. When the data were pooled over the years, gradual differences between the sites, which were seldom detected at individual sampling periods, became evident for different measurements of species richness and species diversity and corresponded to a contamination gradient established between Elbe > Inner Eider, Outer Eider > Helgoland. Despite seasonal variations, which were observed in almost all measurements, these gradual differences were found in both seasons.

  2. Spatial variability in SeaWiFS imagery of the South Atlantic bight as evidenced by gradients (fronts) in chlorophyll a and water-leaving radiance

    NASA Astrophysics Data System (ADS)

    Bontempi, Paula S.; Yoder, James A.

    2004-05-01

    Ocean margin waters contain a host of dissolved and particulate materials of terrestrial and marine origin. The presence of these materials can confound the chlorophyll a (chl a) estimates retrieved by ocean-color satellites' empirical algorithms. We apply edge detection software to chlorophyll a and water-leaving radiance ( Lwn) data from 1998 sea-viewing wide field-of-view sensor (SeaWiFS) imagery to examine this problem within ocean margin waters off the southeastern continental United States (SEC) and South Atlantic bight (SAB). We identify the location of boundaries differentiating waters containing different backscattering components. Identifying those areas where apparent chl a gradients may be caused by differential backscattering helps to determine the location of those gradients caused by real changes in chl a concentrations. An onshore/offshore phytoplankton gradient and seasonal signal not previously detected in SEC waters was revealed from examination of cross-shelf transect data for the months of the study. Phytoplankton concentrations and associated gradients or fronts were connected with the inner, middle or outer shelf based on the biological response to local physical and atmospheric forcings. River flow and wind stress affect inner shelf chl a distributions, while offshore chl a distributions are controlled by Gulf Stream meanders. Carolina Capes' oceanography influenced chl a frontal variability in that local region. We also explore the possibility of utilizing the edge detection algorithm to delineate boundaries between waters dominated by different algal classes.

  3. Organic contaminants of emerging concern in sediments and flatfish collected near outfalls discharging treated wastewater effluent to the Southern California Bight.

    PubMed

    Maruya, Keith A; Vidal-Dorsch, Doris E; Bay, Steven M; Kwon, Jeong W; Xia, Kang; Armbrust, Kevin L

    2012-12-01

    To investigate the occurrence and bioaccumulation of organic contaminants of emerging concern (CECs) near four major wastewater ocean outfalls in the Southern California Bight, more than 75 pharmaceutical and personal care products, current-use pesticides, and industrial/commercial chemicals were analyzed in sediment and liver tissues of hornyhead turbot (Pleuronichthys verticalis) using gas and liquid chromatography-mass spectrometry. Although most CECs targeted were infrequently detected or not detectable, triclosan, 4-nonylphenol (4-NP) and bis(2-ethylhexylphthalate) were detected in all sediments at median (maximum) concentrations of 5.1 (8.6), 30 (380), and 121 (470) µg/kg, respectively. In the liver, 4-NP and polybrominated diphenyl ether (PBDE) congeners 47 and 99 were detected in >90% of samples at median (maximum) concentrations of 85 (290) and 210 (480) µg/kg, respectively. The sedative diazepam was detected in all liver samples, but was infrequently detected in sediments. Sediment and liver concentrations across outfall locations ranged over several orders of magnitude and were elevated relative to a reference site. Relative to sediment, accumulation in liver of PBDEs 47 and 99 was comparable to that for legacy organochlorines, confirming their high bioaccumulation potential and suggesting their inclusion in future tissue monitoring studies. Mean tissue PBDE and diazepam concentrations were higher in livers from male versus female P. verticalis, suggesting that gender differences also be considered in designing such studies.

  4. Bight of Benin: a Maternal Perspective of Four Beninese Populations and their Genetic Implications on the American Populations of African Ancestry.

    PubMed

    Primativo, Giuseppina; Ottoni, Claudio; Biondi, Gianfranco; Serafino, Sara; Martínez-Labarga, Cristina; Larmuseau, Maarten H D; Scardi, Michele; Decorte, Ronny; Rickards, Olga

    2017-03-01

    The understanding of the first movements of the ancestral populations within the African continent is still unclear, particularly in West Africa, due to several factors that have shaped the African genetic pool across time. To improve the genetic representativeness of the Beninese population and to better understand the patterns of human settlement inside West Africa and the dynamics of peopling of the Democratic Republic of Benin, we analyzed the maternal genetic variation of 193 Beninese individuals belonging to Bariba, Berba, Dendi, and Fon populations. Results support the oral traditions indicating that the western neighbouring populations have been the ancestors of the first Beninese populations, and the extant genetic structure of the Beninese populations is most likely the result of admixture between populations from neighbouring countries and native people. The present findings highlight how the Beninese populations contributed to the gene pool of the extant populations of some American populations of African ancestry. This strengthens the hypothesis that the Bight of Benin was not only an assembly point for the slave trade during the Trans-Atlantic Slave Trade but also an important slave trapping area.

  5. Cenozoic biogenic mounds and buried Miocene(?) barrier reef on a predominantly cool-water carbonate continental margin—Eucla basin, western Great Australian Bight

    NASA Astrophysics Data System (ADS)

    Feary, David A.; James, Noel P.

    1995-05-01

    The southern continental margin of Australia is the largest area of cool-water carbonate shelf deposition on the globe. Interpretation of 5495 km of airgun seismic-reflection data in the western part of the Great Australian Bight indicates that the 700-m-thick Cenozoic section of the offshore Eucla basin was deposited largely as a prograding cool-water, middle- to high-latitude carbonate ramp, characterized by widespread development of broad, low-relief, biogenic (bryozoan[?]-sponge), shelf and upper-slope mounds. The succession also contains a spectacular and extensive (>475 km long) buried middle Miocene barrier reef (the Miocene Little Barrier Reef) parallel to the modern shelf edge. This rimmed carbonate platform margin represents an episode of warm-water sedimentation during a global climatic optimum, probably coupled with strong eastward flow of a proto-Leeuwin Current. The late Miocene eustatic sea-level fall produced an areally restricted debris-apron sequence at the foot of the reef escarpment. The carbonate platform is capped by a Neogene cool-water carbonate ramp succession typified by aggradational to sigmoidal sequences, punctuated by periods of cold(?)-water, sea-floor erosion. Interpretation of this succession in the light of global and local tectonic and oceanographic events illustrates the dominant influence of water temperature on carbonate platform and reef growth throughout the Cenozoic.

  6. Absorption and Attenuation Coefficients Using the WET Labs ac-s in the Mid-Atlantic Bight: Field Measurements and Data Analysis

    NASA Technical Reports Server (NTRS)

    Ohi, Nobuaki; Makinen, Carla P.; Mitchell, Richard; Moisan, Tiffany A.

    2008-01-01

    Ocean color algorithms are based on the parameterization of apparent optical properties as a function of inherent optical properties. WET Labs underwater absorption and attenuation meters (ac-9 and ac-s) measure both the spectral beam attenuation [c (lambda)] and absorption coefficient [a (lambda)]. The ac-s reports in a continuous range of 390-750 nm with a band pass of 4 nm, totaling approximately 83 distinct wavelengths, while the ac-9 reports at 9 wavelengths. We performed the ac-s field measurements at nine stations in the Mid-Atlantic Bight from water calibrations to data analysis. Onboard the ship, the ac-s was calibrated daily using Milli Q-water. Corrections for the in situ temperature and salinity effects on optical properties of water were applied. Corrections for incomplete recovery of the scattered light in the ac-s absorption tube were performed. The fine scale of spectral and vertical distributions of c (lambda) and a (lambda) were described from the ac-s. The significant relationships between a (674) and that of spectrophotometric analysis and chlorophyll a concentration of discrete water samples were observed.

  7. Population Dynamics and Diet of the Madamango Sea Catfish Cathorops spixii (Agassiz, 1829) (Siluriformes: Ariidae) in a Tropical Bight in Southeastern Brazil

    PubMed Central

    Denadai, Márcia; Pombo, Maíra; Santos, Flávia Borges; Bessa, Eduardo; Ferreira, Adriana; Turra, Alexander

    2013-01-01

    The madamango sea catfish, Cathorops spixii (Siluriformes: Ariidae), is often among the most abundant fishes on the South American Atlantic coast. In the present study, conducted in shallow, non-estuarine coastal areas of Caraguatatuba Bight in southeastern Brazil, collections of this species, the most abundant member of the ichthyofauna, included primarily medium-sized individuals, indicating that the area may play a specific role in their development. Although studies of the local ichthyofauna have been much neglected, the area is economically important and its ecological significance is undervalued. This study primarily treats habitat use by C. spixii, assessing certain population parameters and the dietary composition. Monthly samples were taken from August 2003 through October 2004, with three trawls in two areas, corresponding to depths of about 1 to 4 m. The catfish showed two main peaks of abundance in the area, in April/May and July 2004. A mode around 9 cm SL persisted through time, and the entrance of younger recruits peaked from January to April. The low estimate for body-growth parameters (K = 0.16) corroborates some K-strategist characteristics of the species. The asymptotic length was 27.3 cm SL and total mortality (Z) was 1.01 yr−1. Cathorops spixii showed an omnivorous feeding habit, preying mainly upon polychaetes, copepods and bivalves, with considerable seasonality in its diet. PMID:24282575

  8. Contaminants still high in top-level carnivores in the Southern California Bight: levels of DDT and PCBs in resident and transient pinnipeds.

    PubMed

    Blasius, Mary Ellen; Goodmanlowe, Gwen D

    2008-12-01

    Highly industrialized areas, such as the Southern California Bight, often have high levels of contaminants in marine sediments, which can cause chronic exposure to organisms long after their use has ceased. tDDT and tPCB were analyzed in the blubber of 145 stranded pinnipeds that died at local marine mammal centers between 1994 and 2006. Resident species (California sea lion and Pacific harbor seal) had significantly higher concentrations of tDDT and tPCB than the transient species (northern elephant seal). Adult female California sea lions had significantly lower concentrations of tDDT and tPCB than pups, yearlings, and adult males. Concentrations of both tDDT and tPCB in California sea lions significantly declined over time, but did not change in northern elephant seals. Current concentrations of tDDT and tPCB in California sea lions and harbor seals are among the highest values reported worldwide for marine mammals and exceed those reported to cause adverse health effects.

  9. A numerical investigation of the interannual-to-interpentadal variability of the along-shelf transport in the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Zhang, Shuwen; Luo, Yiyong; Rothstein, Lewis M.; Gao, Kun

    2016-07-01

    A numerical simulation using the Regional Ocean Modeling System (ROMS) indicates that there was significant interannual-to-interpentadal variability of along-shelf transport and water properties over the Middle Atlantic Bight (MAB) from 2004 to 2013. To examine the relative contribution from local atmospheric forcing versus remote oceanic open boundary forcing to such low-frequency variability, we implement a suite of process oriented numerical experiments. Results show that the interannual variability is dominated by remote forcing from the open boundaries of the region rather than by local atmospheric forcing. The penetration of the Labrador Current into the region contributes to a significant increase of along-shelf transport in the winters of 2009 and 2010. By contrast, the anti-cyclonic mesoscale eddies associated with the Gulf Stream decrease the background along-shelf jet and, in certain cases, even reverse the along-shelf transport. In addition, the along-shelf transport appears to possess an interpentadal variation, i.e., weaker during 2004-2008 but stronger during 2009-2013, which is found caused by the migration of the Gulf Stream.

  10. High-resolution stratigraphy of a Mississippi subdelta-lobe progradation in the Barataria Bight, north-central Gulf of Mexico

    USGS Publications Warehouse

    Flocks, J.G.; Ferina, N.F.; Dreher, C.; Kindinger, J.L.; FitzGerald, D.M.; Kulp, M.A.

    2006-01-01

    The coastal zone of southeastern Louisiana is the product of numerous cycles of progradation, abandonment, and marine transgression of the Mississippi River delta. Currently, the shoreline in the Barataria Bight is undergoing significant erosion and retreat, and understanding its evolution is crucial in stabilization efforts. This study uses an extensive collection of geophysical and sediment core data from Barataria Bay and offshore to develop a geologic model of the shallow (< 10 m) subsurface. The purpose of the model is twofold: (1) establish the stratigraphic architecture of a subdelta lobe of the Bayou des Families delta, deposited by the Mississippi River approximately 4000 years before present; and (2) provide a high-resolution description of the geologic framework in a context that can be applied to coastal management issues in similar fluvially dominated coastal environments worldwide. The results of the study demonstrate how high-quality geologic data from the coastal environment can be used not only to further our understanding of shoreline evolution but also to provide pertinent information for coastal management needs.

  11. Variability in pigment concentration in warm-core rings as determined by coastal zone color scanner satellite imagery from the Mid-Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Garcia-Moliner, Graciela; Yoder, James A.

    1994-01-01

    A time series of coastal zone color scanner (CZCS) derived chlorophyll (CZCS-chl) and sea surface temperature (SST) satellite imagery was developed for the Mid-Atlantic Bight (MAB). Warm-core rings (WCR) were identified by both the warmer SST signal as well as the low pigment concentrations of their cores. The variation in pigment concentrations and SST observed in satellite imagery over the geographic range and life span of four WCRs is investigated. The hypotheses are that pigment concentration increase during the lifetime of the WCR is a response to processes such as convective overturn, upwelling, edge enhancement due to increased vertical mixing, active convergence, or lateral exchange. Empirical orthogonal function analysis (EOF) is used to investigate the relationship between SST and pigment patterns observed in the presence of a WCR. The first two EOF modes explain more than 80% of the variability observed in all four WCRs and in both (SST and pigment) data sets. The results of this study show that, at the synoptic scales of staellite data, the variability observed in the WCRs is greater at the periphery of the rings. These results show that advective entrainment, rather than processes at ring center (e.g., shoaling of the pycnocline/nutricline in response to frictional decay) or at the periphery due to other processes such as vertical mixing, is the mechanism responsible for the observed variability.

  12. Material exchange and food web of seagrass beds in the Sylt-Rømø Bight: how significant are community changes at the ecosystem level?

    NASA Astrophysics Data System (ADS)

    Asmus, H.; Asmus, R.

    2000-07-01

    Material exchange, biodiversity and trophic transfer within the food web were investigated in two different types of intertidal seagrass beds: a sheltered, dense Zostera marina bed and a more exposed, sparse Z. noltii bed, in the Northern Wadden Sea. Both types of Zostera beds show a seasonal development of above-ground biomass, and therefore measurements were carried out during the vegetation period in summer. The exchange of particles and nutrients between seagrass beds and the overlying water was measured directly using an in situ flume. Particle sedimentation [carbon (C), nitrogen (N) and phosphorus (P) constituents] from the water column prevailed in dense seagrass beds. In the sheltered, dense seagrass bed, a net particle uptake was found even on windy days (7-8 Beaufort). Dissolved inorganic N and orthophosphate were mainly taken up by the dense seagrass bed. At times of strong winds, nutrients were released from the benthic community to tidal waters. In a budget calculation of total N and total P, the dense seagrass beds were characterised as a material sink. The seagrass beds with sparse Z. noltii were a source of particles even during calm weather. The uptake of dissolved inorganic N in the sparse seagrass bed was low but significant, while the uptake of inorganic phosphate and silicate by seagrasses and their epiphytes was exceeded by release processes from the sediment into the overlying water. Estimates at the ecosystem level showed that material fluxes of seagrass beds in the Sylt-Rømø Bight are dominated by the dense type of Zostera beds. Therefore, seagrass beds act as a sink for particles and for dissolved inorganic nutrients. During storms, seagrass beds are distinct sources for inorganic nutrients. The total intertidal area of the Sylt-Rømø Bight could be described as a sink for particles and a source for dissolved nutrients. This balance of the material budget was estimated by either including or excluding seagrass beds. Including the

  13. On the dynamics of compound bedforms in high-energy tidal channels: field observations in the German Bight and the Danish Wadden Sea

    NASA Astrophysics Data System (ADS)

    Ernstsen, Verner B.; Winter, Christian; Becker, Marius; Bartholdy, Jesper

    2010-05-01

    Tidal inlets are a common feature along much of the world's coastlines. They interrupt the alongshore continuity of shoreline processes, and by being exposed to both wave and current forcing, tidal inlets belong to the morphologically most dynamic and complex coastal systems on Earth. The tidal channels in these inlets are characterized by high flow velocities and, accordingly, the channel beds are typically sandy and covered with bedforms. The bedform fields in nature are often complex systems with larger primary-bedforms superimposed by smaller secondary-bedforms (cf. Bartholdy et al., 2002). There is a considerable amount of detailed field investigations on the dynamics of primary-bedforms at various temporal scales, ranging from short- to long-term tide-related cycles to flood hydrographs to seasonality. However, Julien et al. (2002) stated that a composite analysis of primary- and secondary-bedforms is recommended for future studies on resistance to flow. Such knowledge on the behaviour of compound bedforms is still deficient. In this study, we combine the findings on the dynamics of primary- and secondary-bedform height from detailed field investigations carried out in two high-energy tidal channels during 2007 and 2008: the Knudedyb tidal inlet channel in the Danish Wadden Sea and the Innenjade tidal channel in the Jade Bay, German Bight (both survey areas being ebb-dominated). We provide process-based explanations of the bedform behaviour and present a conceptual model of compound bedform dynamics. The conducted field investigations comprised repetitive, simultaneous measurements of high-resolution swath bathymetry (using a multibeam echosounder system) and flow velocity (using an acoustic Doppler current profiler) in combination with detailed spatial mapping of bed material characteristics (from grab sampling of bed material). For an objective and discrete analysis of primary- and secondary-bedforms a modified version of the bedform tracking tool

  14. Tools to evaluate seafloor integrity: comparison of multi-device acoustic seafloor classifications for benthic macrofauna-driven patterns in the German Bight, southern North Sea

    NASA Astrophysics Data System (ADS)

    Holler, Peter; Markert, Edith; Bartholomä, Alexander; Capperucci, Ruggero; Hass, H. Christian; Kröncke, Ingrid; Mielck, Finn; Reimers, H. Christian

    2016-12-01

    To determine the spatial resolution of sediment properties and benthic macrofauna communities in acoustic backscatter, the suitability of four acoustic seafloor classification devices (single-beam echosounder with RoxAnn and QTC 5.5 seafloor classification system, sidescan sonar with QTC Swathview seafloor classification, and multi-beam echosounder with QTC Swathview seafloor classification) was compared in a study area of approx. 6 km2 northwest of the island of Helgoland in the German Bight, southern North Sea. This was based on a simple similarity index between simultaneous sidescan sonar, single-beam echosounder and multi-beam echosounder profiling spanning the period 2011-2014. The results show a high similarity between seafloor classifications based on sidescan sonar and RoxAnn single-beam systems, in turn associated with a lower similarity for the multi-beam echosounder system. Analyses of surface sediment samples at 39 locations along four transects (0.1 m2 Van Veen grab) revealed the presence of sandy mud (southern and western parts), coarse sand, gravel and cobbles. Rock outcrops were identified in the north-eastern and eastern parts. A typical Nucula nitidosa-Abra alba community was found in sandy muds to muddy sands in the northern part, whereas the southern part is characterised by widespread occurrence of the ophiuroid brittle star Amphiura filiformis. A transitional N. nitidosa-A. filiformis community was detected in the central part. Moreover, the southern part is characterised by a high abundance of A. filiformis and its commensal bivalve Kurtiella bidentata. The high number of A. filiformis feeding arms (up to ca. 6,800 per m2) can largely explain the gentle change of backscatter intensity along the tracks, because sediment composition and/or seafloor structures showed no significant variability.

  15. Highly dynamic biological seabed alterations revealed by side scan sonar tracking of Lanice conchilega beds offshore the island of Sylt (German Bight)

    NASA Astrophysics Data System (ADS)

    Heinrich, C.; Feldens, P.; Schwarzer, K.

    2016-10-01

    Hydroacoustic surveys are common tools for habitat investigation and monitoring that aid in the realisation of the aims of the EU Marine Directives. However, the creation of habitat maps is difficult, especially when benthic organisms densely populate the seafloor. This study assesses the sensitivity of entropy and homogeneity image texture parameters derived from backscatter strength data to benthic habitats dominated by the tubeworm Lanice conchilega. Side scan sonar backscatter surveys were carried out in 2010 and 2011 in the German Bight (southern North Sea) at two sites approx. 20 km offshore of the island of Sylt. Abiotic and biotic seabed facies, such as sorted bedforms, areas of fine to medium sand and L. conchilega beds with different tube densities, were identified and characterised based on manual expert analysis and image texture analysis. Ground truthing was performed by grab sampling and underwater video observations. Compared to the manual expert analysis, the k-means classification of image textures proves to be a semi-automated method to investigate small-scale differences in a biologically altered seabed from backscatter data. The texture parameters entropy and homogeneity appear linearly interrelated with tube density, the former positively and the latter negatively. Reinvestigation of one site after 1 year showed an extensive change in the distribution of the L. conchilega-altered seabed. Such marked annual fluctuations in L. conchilega tube cover demonstrate the need for dense time series and high spatial coverage to meaningfully monitor ecological patterns on the seafloor with acoustic backscatter methods in the study region and similar settings worldwide, particularly because the sand mason plays a pivotal role in promoting biodiversity. In this context, image texture analysis provides a cost-effective and reproducible method to track biologically altered seabeds from side scan sonar backscatter signatures.

  16. Body growth and reproduction of individuals of the sciaenid fish Stellifer rastrifer in a shallow tropical bight: A cautionary tale for assumptions regarding population parameters

    NASA Astrophysics Data System (ADS)

    Pombo, Maíra; Denadai, Márcia Regina; Turra, Alexander

    2013-05-01

    Knowledge of population parameters and the ability to predict their responses to environmental changes are useful tools to aid in the appropriate management and conservation of natural resources. Samples of the sciaenid fish Stellifer rastrifer were taken from August 2003 through October 2004 in shallow areas of Caraguatatuba Bight, southeastern Brazil. The results showed a consistent presence of length-frequency classes throughout the year and low values of the gonadosomatic index of this species, indicating that the area is not used for spawning or residence of adults, but rather shelters individuals in late stages of development. The results may serve as a caveat for assessments of transitional areas such as the present one, the nursery function of which is neglected compared to estuaries and mangroves. The danger of mismanaging these areas by not considering their peculiarities is emphasized by using these data as a study case for the development of some broadly used population-parameter analyses. The individuals' body growth parameters from the von Bertalanffy model were estimated based on the most common approaches, and the best values obtained from traditional quantification methods of selection were very prone to bias. The low gonadosomatic index (GSI) estimated during the period was an important factor in stimulating us to select more reliable parameters of body growth (L∞ = 20.9, K = 0.37 and Z = 2.81), which were estimated based on assuming the existence of spatial segregation by size. The data obtained suggest that the estimated mortality rate included a high rate of migration of older individuals to deeper areas, where we assume that they completed their development.

  17. The tectonic evolution of the Mid-Atlantic Ridge between 55°55'N and the Bight Transform Fault during the past 6 Ma

    NASA Astrophysics Data System (ADS)

    Benediktsdottir, A.; Hey, R. N.; Martinez, F.; Hoskuldsson, A.

    2014-12-01

    We present a new propagating rift model of the Mid-Atlantic Ridge between 55°55'N and the Bight Transform Fault (BTF) explaining the tectonic history of the area during the past 6 Ma, using marine magnetic anomalies collected in the fall of 2013. The data consist of thirteen flowline parallel lines across the ridge and they show that the accretion across the ridge has not been symmetric. Using Magellan, a new tool to model magnetic anomalies, we obtain a tectonic evolution of the area for the past 6 Ma. The area just south of the BTF (at 0-20 km distance) is characterized by a very large asymmetry in the magnetic data. This asymmetry is most clearly seen within the Brunhes anomaly, which has a big divide in it. Our model suggests that the ridge has shifted twice some 8-12 km to the east within the past 2 Ma resulting from two very rapid rift propagations. We could not determine whether the propagations were to the south or north because of very rapid propagation rates. The tectonic evolution of the area 20-90 km south of the BTF is simpler and the model is more readily understood. The model suggests that a few short lived propagators cause asymmetry in the area. They all, but one, propagate north toward the BTF and all, but one, transfer lithosphere from the Eurasian plate to the North-American plate. Unlike the prominent far reaching (> 100km) propagators just south of Iceland these propagators are short. They play an important role in the tectonic evolution of the ridge and our results suggest that the Mid-Atlantic Ridge in this area is very dynamic.

  18. Dissolved methane concentration and flux in the coastal zone of the Southern California Bight-Mexican sector: Possible influence of wastewater

    NASA Astrophysics Data System (ADS)

    Castro-Morales, Karel; Macías-Zamora, J. Vinicio; Canino-Herrera, S. Raúl; Burke, Roger A.

    2014-05-01

    We measured dissolved methane concentrations ([CH4]) in the coastal zone of the Southern California Bight-Mexican sector (SCBMex) during two cruises: S1 in the USA-Mexico Border Area (BA) during a short rainstorm and S2 in the entire SCBMex during a drier period a few days later. High spatial variability in surface mixed layer (ML) [CH4] was observed, ranging from 2.2 nmol L-1 to 17.8 nmol L-1. ML-[CH4] was supersaturated at all BA stations during both cruises. The highest [CH4] was 72.4 nmol L-1 (2819 % supersaturated) measured at 10 m depth during S2, about 3 km southwest of the discharge point of the South Bay Ocean Outfall (SBOO). Our results show an apparent connection between wastewater treatment discharges and [CH4]. Application of a sewer CH4 production model suggests that the SBOO may be a large source of CH4 to the BA and points to the need to consider point sources in developing coastal marine CH4 budgets for highly populated areas. Based on our data, the SCBMex appears to be a relatively strong source of CH4 to the atmosphere compared to other Pacific Basin areas. The average BA sea-to-air CH4 flux (F) during S1 was (15.5 ± 8.6) × 10-2 nmol m-2 s-1, about 1.5 times higher than F during S2, which had a flux of (9.5 ± 6.9) × 10-2 nmol m-2 s-1 mainly due to the higher wind speed during S1.

  19. A numerical analysis of shipboard and coastal zone color scanner time series of new production within Gulf Stream cyclonic eddies in the South Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Pribble, J. Raymond; Walsh, John J.; Dieterle, Dwight A.; Mueller-Karger, Frank E.

    1994-01-01

    Eddy-induced upwelling occurs along the western edge of the Gulf Stream between Cape Canaveral, Florida, and Cape Hatteras, North Carolina, in the South Atlantic Bight (SAB). Coastal zone color scanner images of 1-km resolution spanning the period April 13-21, 1979, were processed to examine these eddy features in relation to concurrent shipboard and current/temperature measurements at moored arrays. A quasi-one-dimensional (z), time dependent biological model, using only nitrate as a nutrient source, has been combined with a three-dimensional physical model in an attempt to replicate the observed phytoplankton field at the northward edge of an eddy. The model is applicable only to the SAB south of the Charleston Bump, at approximately 31.5 deg N, since no feature analogous to the bump exists in the model bathymetry. The modeled chlorophyll, nitrate, and primary production fields of the euphotic zone are very similar to those obtained from the satellite and shipboard data at the leading edges of the observed eddies south of the Charleston Bump. The horizontal and vertical simulated fluxes of nitrate and chlorophyll show that only approximately 10% of the upwelled nitrate is utilized by the phytoplankton of the modeled grid box on the northern edge of the cyclone, while approximately 75% is lost horizontally, with the remainder still in the euphotic zone after the 10-day period of the model. Loss of chlorophyll due to sinking is very small in this strong upwelling region of the cyclone. The model is relatively insensitive to variations in the sinking parameterization and the external nitrate and chlorophyll fields but is very sensitive to a reduction of the maximum potential growth rate to half that measured. Given the success of this model in simulating the new production of the selcted upwelling region, other upwelling regions for which measurements or successful models of physical and biological quantities and rates exist could be modeled similarly.

  20. Remote Sensing of the Absorption Coefficients and Chlorophyll a Concentration in the U.S. Southern Middle Atlantic Bight from SeaWiFS and MODIS-Aqua

    NASA Technical Reports Server (NTRS)

    Pan, Xiaoju; Mannino, Antonio; Russ, Mary E.; Hooker, Stanford B.

    2008-01-01

    At present, satellite remote sensing of coastal water quality and constituent concentration is subject to large errors as compared to the capability of satellite sensors in oceanic waters. In this study, field measurements collected on a series of cruises within U.S. southern Middle Atlantic Bight (SMAB) were applied to improve retrievals of satellite ocean color products in order to examine the factors that regulate the bio-optical properties within the continental shelf waters of the SMAB. The first objective was to develop improvements in satellite retrievals of absorption coefficients of phytoplankton (a(sub ph)), colored dissolved organic matter (CDOM) (a(sub g)), non-pigmented particles (a(sub d)), and non-pigmented particles plus CDOM (a(sub dg)), and chlorophyll a concentration ([Chl_a]). Several algorithms were compared to derive constituent absorption coefficients from remote sensing reflectance (R(sub rs)) ratios. The validation match-ups showed that the mean absolute percent differences (MAPD) were typically less than 35%, although higher errors were found for a(sub d) retrievals. Seasonal and spatial variability of satellite-derived absorption coefficients and [Chl_a] was apparent and consistent with field data. CDOM is a major contributor to the bio-optical properties of the SMAB, accounting for 35-70% of total light absorption by particles plus CDOM at 443 nm, as compared to 30-45% for phytoplankton and 0-20% for non-pigmented particles. The overestimation of [Chl_a] from the operational satellite algorithms may be attributed to the strong CDOM absorption in this region. River discharge is important in controlling the bio-optical environment, but cannot explain all of the regional and seasonal variability of biogeochemical constituents in the SMAB.

  1. Tools to evaluate seafloor integrity: comparison of multi-device acoustic seafloor classifications for benthic macrofauna-driven patterns in the German Bight, southern North Sea

    NASA Astrophysics Data System (ADS)

    Holler, Peter; Markert, Edith; Bartholomä, Alexander; Capperucci, Ruggero; Hass, H. Christian; Kröncke, Ingrid; Mielck, Finn; Reimers, H. Christian

    2017-04-01

    To determine the spatial resolution of sediment properties and benthic macrofauna communities in acoustic backscatter, the suitability of four acoustic seafloor classification devices (single-beam echosounder with RoxAnn and QTC 5.5 seafloor classification system, sidescan sonar with QTC Swathview seafloor classification, and multi-beam echosounder with QTC Swathview seafloor classification) was compared in a study area of approx. 6 km2 northwest of the island of Helgoland in the German Bight, southern North Sea. This was based on a simple similarity index between simultaneous sidescan sonar, single-beam echosounder and multi-beam echosounder profiling spanning the period 2011-2014. The results show a high similarity between seafloor classifications based on sidescan sonar and RoxAnn single-beam systems, in turn associated with a lower similarity for the multi-beam echosounder system. Analyses of surface sediment samples at 39 locations along four transects (0.1 m2 Van Veen grab) revealed the presence of sandy mud (southern and western parts), coarse sand, gravel and cobbles. Rock outcrops were identified in the north-eastern and eastern parts. A typical Nucula nitidosa- Abra alba community was found in sandy muds to muddy sands in the northern part, whereas the southern part is characterised by widespread occurrence of the ophiuroid brittle star Amphiura filiformis. A transitional N. nitidosa- A. filiformis community was detected in the central part. Moreover, the southern part is characterised by a high abundance of A. filiformis and its commensal bivalve Kurtiella bidentata. The high number of A. filiformis feeding arms (up to ca. 6,800 per m2) can largely explain the gentle change of backscatter intensity along the tracks, because sediment composition and/or seafloor structures showed no significant variability.

  2. Coupled physical, chemical, and microbiological measurements suggest a connection between internal waves and surf zone water quality in the Southern California Bight

    NASA Astrophysics Data System (ADS)

    Wong, Simon H. C.; Santoro, Alyson E.; Nidzieko, Nicholas J.; Hench, James L.; Boehm, Alexandria B.

    2012-02-01

    with phosphate concentration in both years, silicate in 2005, and fecal indicator bacteria measurements in 2006. The results suggest internal waves are an important transport mechanism of nutrient-rich subthermocline water to the very nearshore in the Southern California Bight, and may facilitate the transport of FIB into the surf zone or enhance persistence of land-derived FIB.

  3. Parasites of the flounder Platichthys flesus (L.) from the German Bight, North Sea, and their potential use in ecosystem monitoring. A. Infection characteristics of potential indicator species

    NASA Astrophysics Data System (ADS)

    Schmidt, V.; Zander, S.; Körting, W.; Steinhagen, D.

    2003-10-01

    As part of integrated biological-effect monitoring, the parasite fauna of the flounder Platichthys flesus (L.) was investigated at five locations in the German Bight, with a view to using parasite species as bio-indicators. Over a period of 6 years, parasites from 30 different taxa were identified, but only 7 taxa of the parasite community occurred regularly at all locations and in sufficient abundance that they could be considered as potential indicator species. These species were the ciliophoran Trichodina spp., the copepods Acanthochondria cornuta, Lepeophtheirus pectoralis and Lernaeocera branchialis, the helminths Zoogonoides viviparus and Cucullanus heterochrous and metacercaria of an unidentified digenean species. Infection characteristics of these parasites are presented, with a comparison of the results from individual sampling periods and those of the long-term data set. Natural influences on the infection levels, such as temporal variations, habitat conditions and host-related factors, were evaluated. All of these parasite species showed significant differences in their infection levels between the Elbe estuary, as the most polluted site, and the less polluted coastal and marine locations: Helgoland, Outer Eider estuary and Spiekeroog, especially in the long-term data set. Gradual differences between the Elbe, the Outer Eider and Helgoland, which were not detected in individual sampling periods, also became evident in the pooled-data set. These were found in the prevalence of Trichodina spp., A. cornuta, Z. viviparus and C. heterochrous. Although salinity is considered as the most important natural factor, influencing the distribution pattern of the majority of the potential indicator species, infection levels of most of these species differed between locations with similar salinity conditions. Infection levels corresponded to a contamination gradient (Elbe > Inner Eider, Outer Eider > Helgoland) established across the locations. Seasonal variation in

  4. Fine-scale spatial and temporal plankton distributions in the Southern California Bight: lessons from in situ microscopes and broadband echosounders

    NASA Astrophysics Data System (ADS)

    Briseno-Avena, Christian

    Phytoplankton and zooplankton are important components of marine ecosystems, and play a major role in the biological pump, affecting carbon transport in the global oceans. Their dynamic heterogeneous spatial and temporal distributions require special tools for observing them at the ecological scales relevant to the individual organisms. In this work, I used optic and acoustic methods to study plankton organisms at spatial scales of meters and temporal scales ranging from minutes to months. Using two in situ microscopes I described the fine-scale vertical distribution of phytoplankton and several zooplankton taxa in a coastal location in the Southern California Bight. Highly resolved spatial observations revealed cryptic maxima of fluorescent particles not observed with traditional fluorometers. Furthermore, this high sampling resolution revealed that water density, and not depth, regulated the vertical position, and interactions between observed phytoplankton and zooplankton distributions. Underwater acoustic echosounders can be powerful tools to observe in situ plankton distributions. Interpreting the acoustic echoes, however, requires highly calibrated instruments and ground-truthing experiments to identify the source of acoustic signals. This work presents the description of a novel combination of a broadband, high-frequency (1.5-2.5 MHz) echosounder and a stereoscopic camera --combined, these systems can localize the echo produced by an individual target while simultaneously providing visual identification of the target. This work has provided one of the first comparisons of in situ measured broadband target strength (BTS) and the expected signal using a physical model. The results of this experiment revealed unexpected, important differences between measured and modeled BTS. This system was also used to make in situ observations of individual fragile gelatinous organisms, marine snow particles and phytoplankton, providing evidence of their significant acoustic

  5. Assessing the fidelity of surface currents from a coastal ocean model and HF radar using drifting buoys in the Middle Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Kuang, Liang; Blumberg, Alan F.; Georgas, Nickitas

    2012-08-01

    The rapid expansion of urbanization along the world's coastal areas requires a more comprehensive and accurate understanding of the coastal ocean. Over the past several decades, numerical ocean circulation models have tried to provide such insight, based on our developing understanding of physical ocean processes. The systematic establishment of coastal ocean observation systems adopting cutting-edge technology, such as high frequency (HF) radar, satellite sensing, and gliders, has put such ocean model predictions to the test, by providing comprehensive observational datasets for the validation of numerical model forecasts. The New York Harbor Observing and Prediction System (NYHOPS) is a comprehensive system for understanding coastal ocean processes on the continental shelf waters of New York and New Jersey. To increase confidence in the system's ocean circulation predictions in that area, a detailed validation exercise was carried out using HF radar and Lagrangian drifter-derived surface currents from three drifters obtained between March and October 2010. During that period, the root mean square (RMS) differences of both the east-west and north-south currents between NYHOPS and HF radar were approximately 15 cm s-1. Harmonic analysis of NYHOPS and HF radar surface currents shows similar tidal ellipse parameters for the dominant M2 tide, with a mean difference of 2.4 cm s-1 in the semi-major axis and 1.4 cm s-1 in the semi-minor axis and 3° in orientation and 10° in phase. Surface currents derived independently from drifters along their trajectories showed that NYHOPS and HF radar yielded similarly accurate results. RMS errors when compared to currents derived along the trajectory of the three drifters were approximately 10 cm s-1. Overall, the analysis suggests that NYHOPS and HF radar had similar skill in estimating the currents over the continental shelf waters of the Middle Atlantic Bight during this time period. An ensemble-based set of particle tracking

  6. Response of the Bight of Benin (Gulf of Guinea, West Africa) coastline to anthropogenic and natural forcing, Part1: Wave climate variability and impacts on the longshore sediment transport

    NASA Astrophysics Data System (ADS)

    Almar, R.; Kestenare, E.; Reyns, J.; Jouanno, J.; Anthony, E. J.; Laibi, R.; Hemer, M.; Du Penhoat, Y.; Ranasinghe, R.

    2015-11-01

    The short, medium and long-term evolution of the sandy coastline of the Bight of Benin in the Gulf of Guinea, West Africa, has become a major regional focal point due to the rapid socio-economic development that is occurring in the region, including rapid urbanization and a sharp increase in harbor-based trade. Harbors have a significant impact on the present evolution of this coast, notably by affecting longshore sediment transport. However, little is known of the environmental drivers, notably the wave climate, that governs longshore sediment transport and the ensuing pattern of shoreline evolution of this coastal zone. This article aims to address this important knowledge gap by providing a general overview of coastal evolution in the Bight of Benin and the physical processes that control this evolution. Here, the 1979-2012 ERA-Interim hindcast is used to understand the temporal dynamics of longshore sediment transport. Oblique waves (annual average Hs=1.36 m, Tp=9.6 s, S-SW incidence) drive an eastward drift of approximately 500,000 m3/yr. The waves driving this large longshore transport can be separated into two components with distinct origins and behavior: wind waves generated locally in the Gulf of Guinea and swell waves generated in the southern hemisphere sub- (30-35°S), and extra-tropics (45-60°S). The analysis undertaken here shows that the contribution to the gross annual longshore transport from swell wave-driven longshore currents is an order of magnitude larger than the local wind wave-driven longshore currents. Swell waves are dominantly generated by westerlies in the 40-60°S zone and to a lesser extent by trade winds at 30-35°S. The longshore sediment drift decay (-5% over 1979-2012) is found to be linked with a decrease in the intensity of westerly winds associated with their southward shift, in addition to a strengthening of the trade winds, which reduces the eastward sediment transport potential. The equatorial fluctuation of the Inter

  7. (The role of zooplankton in the cycling and remineralization of chemical materials in the Southern California Bight): California Basin Study: DOE west coast basin program: Progress report 4, (June 1987--June 1988)

    SciTech Connect

    Small, L.F.; Huh, Chih-An

    1988-06-01

    The overall objective of our research, within the structure of the DOE CaBS (California Basin Study) program, is to understand the transport pathways and mass balances of selected metabolically active and inactive chemical species in the Santa Monica/San Pedro Basins. One focus of our study is to examine the role of zooplankton and micronekton in the cycling and remineralization of chemical materials in the Southern California Bight, with particular reference to C, N and certain radionuclides and trace metals. A second focus is to examine these same radionuclides and trace metals in other reservoirs besides the zooplankton (i.e., in seawater, sediment trap material and bottom sediments). Knowledge of the rates, routes and reservoirs of these nuclides and metals should lead to a cogent model for these elements in Santa Monica/San Pedro Basins. Our zooplankton C and N data, in conjunction with primary production, microbiological and sediment flux data from colleagues in the program, should also lead ultimately to a model of C and N cycling in the basins. 33 refs., 13 figs., 7 tabs.

  8. Use of delta(13)C and delta(15)N, and carbon to nitrogen ratios to evaluate the impact of sewage-derived particulate organic matter on the benthic communities of the Southern California Bight.

    PubMed

    Ramírez-Alvarez, Nancy; Macías-Zamora, José Vinicio; Burke, Roger A; Rodríguez-Villanueva, Lúz Verónica

    2007-11-01

    We measured stable isotope ratios (delta(13)C and delta(15)N) of particulate organic matter (POM) sources and benthic organic matter compartments as well as sediment C to N ratios from the coastal area of the southern end of the Southern California Bight (SCB). We used the isotopic values to evaluate the relative importance of the major POM sources to the sediment and two benthic macroinvertebrates. Application of a simple model to sediment delta(13)C values suggested that sewage-derived POM (SDPOM) supplies an average of 48% of the organic C to study area sediments. Application of a similar model to Spiophanes duplex delta(13)C values suggested that SDPOM from wastewater treatment plants discharging into the SCB could supply up to 57% of the C assimilated by this important benthic macroinvertebrate in areas as far away as 26 km from SDPOM inputs. The stable isotope data for Amphiodia urtica were more difficult to interpret because of the complex feeding habits of this organism.

  9. The complex influences of back-barrier deposition, substrate slope and underlying stratigraphy in barrier island response to sea-level rise: Insights from the Virginia Barrier Islands, Mid-Atlantic Bight, U.S.A.

    NASA Astrophysics Data System (ADS)

    Brenner, Owen T.; Moore, Laura J.; Murray, A. Brad

    2015-10-01

    To understand the relative importance of back barrier environment, substrate slope and underlying stratigraphy in determining barrier island response to RSLR (relative sea-level rise), we use a morphological-behavior model (GEOMBEST) to conduct a series of sensitivity experiments, based on late-Holocene hindcast simulations of an island in the U.S. mid-Atlantic Bight (Metompkin Island, VA) having both salt marsh and lagoonal back-barrier environments, and we draw comparisons between these results and future simulations (2000-2100 AD) of island response to RSLR. Sensitivity analyses indicate that, as a whole, the island is highly sensitive to factors that reduce overall sand availability (i.e., high sand-loss rates and substrates containing little sand). Results also indicate that for all predicted future RSLR scenarios tested, islands having high substrate sand proportions (if allowed to migrate freely) will likely remain subaerial for centuries because of sufficient substrate sand supply and elevation to assist in keeping islands above sea level. Simulation results also lead to basic insights regarding the interactions among substrate slope, back-barrier deposition and island migration rates. In contrast to previous studies, which suggest that changes in substrate slope directly affect the island migration trajectory, we find that-in the presence of back-barrier deposition-the connection between substrate slope and island behavior is modulated (i.e., variability in migration rates is dampened) by changes in back-barrier width. These interactions-which tend to produce changes in shoreface sand content-lead to a negative feedback when the back-barrier deposit contains less sand than the underlying layer, resulting in a stable back-barrier width. Alternatively, a positive feedback arises when the back-barrier deposit contains more sand than the underlying layer, resulting in either back-barrier disappearance or perpetual widening.

  10. Parasites of flounder (Platichthys flesus L.) from the German Bight, North Sea, and their potential use in biological effects monitoring. C. Pollution effects on the parasite community and a comparison to biomarker responses

    NASA Astrophysics Data System (ADS)

    Schmidt, V.; Zander, S.; Körting, W.; Broeg, K.; von Westernhagen, H.; Dizer, H.; Hansen, P. D.; Skouras, A.; Steinhagen, D.

    2003-10-01

    In the frame of an integrated biological effect monitoring programme, the parasite community of flounder (Platichthys flesus) was investigated at different locations in the German Bight from 1995 to 2000. In order to assess the impact of environmental contamination caused by anthropogenic activities on the parasite community, selected parasitological parameters that displayed significant differences between the sampling sites were subjected to correlation analyses with site-specific contamination and individual pollution loads of their fish hosts. In addition, correlation analyses were conducted with the responses of selected genetic, biochemical, histopathological, physiological and immunological parameters of fish, used as potential biomarkers. In total, 802 flounder were analysed for these parameters. Information on the chemical background at the sampling sites was derived from sediment samples and from 120 samples of blue mussel (Mytilus edulis) tissue, collected at each of the sampling sites. Based on chemical data available from the sediment and blue mussel samples, a pollution gradient could be established between the sampling sites for individual contaminants. The relative abundance of Acanthochondria cornuta, Cucullanus heterochrous and Zoogonoides viviparus, and the community measures species richness and number of heteroxenous species decreased with increasing concentrations of individual heavy metals or hydrocarbons in sediment and blue mussel samples. Most of the parasitological parameters significantly reflected the established site-specific contamination gradient, when data were pooled over all sampling campaigns. Significant correlations were also found with the contamination level of individual flounder. The parasitological parameters included the parasite species Lepeophtheirus pectoralis and Lernaeocera branchialis, which were not correlated to site-specific contamination. Several biomarkers were significantly correlated to the abundance of

  11. A new 0.9 Ma oxygen isotope stratigraphy for a shallow-water sedimentary transect across three IODP 317 sites in the Canterbury Bight of southwest Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Ding, Xuan; Wu, YingYing

    2016-04-01

    Sedimentary records in shallow-water environment provide unique opportunity to further our understanding on the regional relative sea level changes in relation to global climate change. Here we present a new 0.9 Ma oxygen isotope stratigraphy for a shallow-water sedimentary transect across three IODP 317 sites in the Canterbury Bight of southwest Pacific Ocean. The three sites are located on the eastern margin of the South Island of New Zealand, including a continental slope site, IODP317-U1352 and two continental shelf sites, IODP317-U1354 and IODP317-U1351. We first generated high resolution benthic foraminifers (Nonionella flemingi) δ18O records for the three sites and a planktonic (Globigerina bulloides) record for the U1352B. An initial chronological framework for the benthic δ18O record of the U1352B was constructed using 8 accelerator mass spectrometry (AMS) radiocarbon dates and 4 biostratigraphic events. Then a refined age model was established by correlating the U1352B benthic δ18O record with the EDC δD record on the AICC2012 time-scale, and the LR04 benthic δ18O stack. Although the U1354B and U1351B have lower sedimentation rates, their benthic δ18O records correlate well with that of U1352B. In order to ensure the accuracy of the chronostratigraphic framework established, we also analyzed the characteristics of sedimentary grain size and the planktonic and benthic δ18O values. In accord with the adjacent sites, the results show that the melt of Southern Alps glaciers due to the warming climate during MIS 11 and 5.5 led to the increased fresh water delivery, with massive terrigenous deposit; and the warm SST during the MIS7 is related with the STF migration, which led to strong current activity, with coarser grain size. Meanwhile, records of benthic δ18O, sedimentation rate and content of >63μm coarse fraction of site U1352 all indicate the MIS 20 was indeed a colder interval compared to subsequent glacial times.

  12. Isotopic evidence for dead fish maintenance of Florida red tides, with implications for coastal fisheries over both source regions of the West Florida shelf and within downstream waters of the South Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Walsh, J. J.; Weisberg, R. H.; Lenes, J. M.; Chen, F. R.; Dieterle, D. A.; Zheng, L.; Carder, K. L.; Vargo, G. A.; Havens, J. A.; Peebles, E.; Hollander, D. J.; He, R.; Heil, C. A.; Mahmoudi, B.; Landsberg, J. H.

    2009-01-01

    Toxic Florida red tides of the dinoflagellate Kareniabrevis have downstream consequences of 500-1000 km spatial extent. Fish stocks, shellfish beds, and harmful algal blooms of similar species occupy the same continental shelf waters of the southeastern United States, amounting to economic losses of more than 25 million dollars in some years. Under the aegis of the Center for Prediction of Red tides, we are now developing coupled biophysical models of the conditions that lead to red tides and impacted coastal fisheries, from the Florida Panhandle to Cape Hatteras. Here, a nitrogen isotope budget of the coastal food web of the West Florida shelf (WFS) and the downstream South Atlantic Bight (SAB) reaffirms that diazotrophs are the initial nutrient source for onset of red tides and now identifies clupeid fish as the major recycled nutrient source for their maintenance. The recent isotope budget of WFS and SAB coastal waters during 1998-2001 indicates that since prehistoric times of Timacua Indian settlements along the Georgia coast during 1075, ∼50% of the nutrients required for large red tides of >1 μg chl l -1 of K.brevis have been derived from nitrogen-fixers, with the other half from decomposing dead sardines and herrings. During 2001, >90% of the harvest of WFS clupeids was by large ichthyotoxic red tides of >10 μg chl l -1 of K.brevis, rather than by fishermen. After onset of the usual red tides in summer of 2006 and 2007, the simulated subsequent fall exports of Florida red tides in September 2007 to North Carolina shelf waters replicate observations of just ∼1 μg chl l -1 on the WFS that year. In contrast, the earlier red tides of >10 μg chl l -1 left behind off West Florida during 2006, with less physical export, are instead 10-fold larger than those of 2007. Earlier, 55 fish kills were associated with these coastal red tides during September 2006, between Tampa and Naples. Yet, only six fish kills were reported there in September 2007. With little

  13. Task 1: Whole-body concentrations of elements in kelp bass (Paralabrax clathratus), kelp rockfish (Sebastes atrovirens), and Pacific sanddab (Citharichthys sordidus) from offshore oil platforms and natural areas in the Southern California Bight

    USGS Publications Warehouse

    Love, Milton S.

    2009-01-01

    Resource managers are concerned that offshore oil platforms in the Southern California Bight may be contributing to environmental contaminants accumulated by marine fishes. To examine this possibility, 18 kelp bass (Paralabrax clathratus), 80 kelp rockfish (Sebastes atrovirens), and 98 Pacific sanddab (Citharichthys sordidus) were collected from five offshore oil platforms and 10 natural areas during 2005-2006 for whole-body analysis of 63 elements. The natural areas, which served as reference sites, were assumed to be relatively uninfluenced by contaminants originating from platforms. Forty-two elements were excluded from statistical comparisons for one of three reasons: they consisted of major cations that were unlikely to accumulate to potentially toxic concentrations under ambient exposure conditions; they were not detected by the analytical procedures; or they were detected at concentrations too low to yield reliable quantitative measurements. The remaining 21 elements consisted of aluminum, arsenic, barium, cadmium, chromium, cobalt, copper, gallium, iron, lead, lithium, manganese, mercury, nickel, rubidium, selenium, strontium, tin, titanium, vanadium, and zinc. Statistical comparisons of these 21 elements indicated that none consistently exhibited higher concentrations at oil platforms than at natural areas. Eight comparisons yielded significant interaction effects between total length (TL) of the fish and the two habitat types (oil platforms and natural areas). This indicated that relations between certain elemental concentrations (i.e., copper, rubidium, selenium, tin, titanium, and vanadium) and habitat type varied by TL of affected fish species. To better understand these interactions, we examined elemental concentrations in very small and very large individuals of affected species. Although significant interactions were detected for rubidium, tin, and selenium in kelp rockfish, the concentrations of these elements did not differ significantly between

  14. Hypoxia Hotspots in the Mississippi Bight

    DTIC Science & Technology

    2006-04-01

    graded gray tones. Bathymetry is from Northern Gulf of Mexico Littoral Initiative (N. Vinogradova. unpublished data, 2004). census was made of benthic ...PARKER, F., 1954, Distribution of the Foraminifera in the northeastern foraminifera from sediment cores: Estuaries, v. 23, p. 488-508. Gulf of Mexico ... benthic boundary layer and seabed processes: indicators of nutrient enrichment in the Gulf of Mexico : Continental Shelf Research, v. 24, p. 899-926

  15. New York Bight Study: Report 5, NY Bight Biological Review Program

    DTIC Science & Technology

    1994-05-01

    of dredged cuts versus undredged flats," Environmental Impact Assessment of Shell Dredging in San Antonio Bay, Texas, Vol V, Appendix C2, report to U.S...Federal Water Pollution Control Act [PL 92-50001, and Endangered Species Act [PL 93-205]), regulations (most notably the Council on Environmental ...se and can be used to examine environmental impacts efficiently. For example, catch-per-unit-effort (CPUE) has long been used as a proxy for abundance

  16. The legacy of sewage sludge disposal in New York bight

    SciTech Connect

    Buchholtz ten Brink, M.; Casso, M.A.; Allison, M.A.; Schleel, J.S.

    1995-12-31

    From 1924 until 1987, New York City disposed of sewage sludge by dumping at the 12-mile dumpsite in 20 m of water off the New York-New Jersey coast. Approximately 125 {times} 10{sup 6} m{sup 3} was deposited, peaking in the early 1980`s. The dumpsite is at the head of the Hudson Shelf Valley, a submerged river channel crossing the continental shelf, in a region of sandy sediments that are regularly reworked by wave action. The introduction of the chemically and texturally distinct `sludge` sediment provides a tracer to study how accumulated anthropogenic deposits are dispersed throughout the region or transferred off the shelf. This work, begun in 1992, focuses on the fate of the material in the valley, ``downstream`` from the dumpsite. Geophysical, chemical, and radiological tools were used to delineate the sedimentary processes, the extent of contaminant dispersal, and the longterm fate of the dump spoils. Sediment derived from the sewage sludge has preferentially deposited on the valley floor relative to the surrounding shelf, resulting in unnaturally high accumulation rates in the upper valley. Dark, sludge-derived sediment is being covered by cleaner deposits from 0 to 26 km downvalley from the dumpsite, but ongoing resuspension and transport of the sediment results in a sewage signal in the uppermost sediments up to 80 km from the dumpsite. Both buried and surface ``sludge`` is subject to biological mixing. The patchy occurrence of the black sediment and interbedded sand layers observed downvalley suggest that resuspension and transport occur episodically, probably during major storm events.

  17. A high resolution water level forecast for the German Bight

    NASA Astrophysics Data System (ADS)

    Niehüser, Sebastian; Dangendorf, Sönke; Arns, Arne; Jensen, Jürgen

    2016-04-01

    Many coastal regions worldwide are potentially endangered by storm surges which can cause disastrous damages and loss of life. Due to climate change induced sea level rise, an accumulation of such events is expected by the end of the 21th century. Therefore, advanced storm surge warnings are needed to be prepared when another storm surge hits the coast. In the shallow southeastern North Sea these storm surge warnings are nowadays routinely provided for selected tide gauge locations along a coastline through state-of-the-art forecast systems, which are based on a coupled system of empirical tidal predictions and numerical storm surge forecasts. Along the German North Sea coastline, the Federal Maritime and Hydrographic Agency in cooperation with the German Weather Service is responsible for the storm surge warnings. They provide accurate, high frequency and real-time water level forecasts for up to six days ahead at selected tide gauge sites via internet, telephone and broadcast. Since water levels along the German North Sea coastline are dominated by shallow water effects and a very complex bathymetric structure of the seabed, the pointwise forecast is not necessarily transferable to un-gauged areas between the tide gauges. Here we aim to close this existing gap and develop water level forecasts with a high spatial (continuously with a resolution of at least 1 kilometer) as well as a high temporal (at least 15-minute values) resolution along the entire German North Sea coastline. We introduce a new methodology for water level forecasts which combines empirical or statistical and numerical models. While the tidal forecast is performed by non-parametric interpolation techniques between un-gauged and gauged sites, storm surges are estimated on the basis of statistical/empirical storm surge formulas taken from a numerical model hindcast. The procedure will be implemented in the operational mode forced with numerical weather forecasts.

  18. New York Bight Study. Report 1. Hydrodynamic Modeling

    DTIC Science & Technology

    1994-08-01

    Study. Report 1, Hydrodynamic mdeling / by Norman W. Scheff ner... Cet alo ] ; prepared for U.S. Army Engineer District, New York. 228 p. iV. ; 28 cm. -H...specify the river boundary condi- tion in this manner, because the head of tide is generally tens of miles up- stream of the river mouth and therefore...including the time for 0MB Nintrcto.s 0704-0188t.r] at .¢rc• .= IR buideriorlh te to verae I our r repons.ewingd instructions, searching existing data

  19. DELFT3D-Modelling of Hydrodynamic and Water Quality Processes in San Diego Bight

    DTIC Science & Technology

    2009-01-01

    Terrill (SIO Scripps), Dr. Lyle Hibler ( PNL ) and Mark Moline (CalPoly) who are funded separately. LONG-TERM GOALS The long-term goal of this...cooperation with Dr. Eric Terrill (SIO Scripps), Dr. Lyle Hibler ( PNL ) and Mark Moline (CalPoly) who are funded separately.

  20. Delft3D-Modelling of Hydrodynamic and Water Quality Processes in San Diego Bight

    DTIC Science & Technology

    2010-09-30

    Terrill (SIO Scripps), Dr. Lyle Hibler ( PNL ) and Mark Moline (CalPoly) who are funded separately. LONG-TERM GOALS The long-term goal of this effort is...October 3, 2002. RELATED PROJECTS This work is a cooperation with Dr. Eric Terrill (SIO Scripps), Dr. Lyle Hibler ( PNL ) and Mark Moline (CalPoly) who are funded separately. 5

  1. Community composition of the rocky intertidal at Helgoland (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Reichert, Katharina; Buchholz, Friedrich; Giménez, Luis

    2008-12-01

    At the rocky island of Helgoland (North Sea), the distribution and abundances of intertidal communities were assessed and the effects of wave exposure and tidal height on the spatial distribution patterns of the communities were evaluated. Macroalgae and invertebrates were sampled quantitatively along line transects in three intertidal locations, a semi-exposed, an exposed and a sheltered one. The semi-exposed location was characterised by (1) Ulva spp. at the high intertidal ( Ulva-community), (2) mussels and periwinkles at the mid intertidal ( Mytilus-community) and (3) Corallina officinalis and mainly the large brown alga Fucus serratus at the low intertidal ( Fucus-community). The exposed location encompassed the mid and low intertidal; at both zones the Fucus-community occurred. The sheltered location was characterised by (1) barnacles ( Balanus-community) and (2) bryozoans, hydrozoans and mainly the large brown alga Ascophyllum nodosum ( Ascophyllum-community). At the semi-exposed, but not at the exposed location the communities changed with the intertidal position. A relationship between wave exposure and the occurrence of specific communities was shown for the sheltered location; in contrast, communities of the semi-exposed and the exposed location appear to be little influenced by wave exposure directly. The community concept and the potential causes of distribution patterns of the defined communities are discussed and suggestions for a future monitoring are given. Variations in the communities at different spatial scales speak in favour of a multiple scale sampling design to monitor changes in the intertidal communities at Helgoland.

  2. On preconditioning of coastal upwelling in the eastern Great Australian Bight

    NASA Astrophysics Data System (ADS)

    KäMpf, Jochen

    2010-12-01

    Using a high-resolution hydrodynamic model, this work explores the formation of a subsurface pool of cold and nutrient-rich water on the continental shelf southwest of Kangaroo Island, South Australia. Findings reveal that localized upwelling in shelf break canyons south of Kangaroo Island play an important role in the pool's formation. Supported by observational evidence, this study suggests a direct link between canyon upwelling, pool formation, and the appearance of coastal upwelling centers in austral summer. The shelf and slope circulation establishing during this season creates a particularly deep canyon upwelling from an average depth of ˜310 m, which is much deeper than previously suggested. Results indicate that model applications, not resolving the shelf break canyons, underestimate upwelling-related volume fluxes across the shelf break by a factor of 3.5 and nitrate fluxes by a factor of 5.

  3. Modeling of Habitat and Foraging Behavior of Beaked Whales in the Southern California Bight

    DTIC Science & Technology

    2013-09-30

    their vocal behavior. APPROACH High-Frequency Acoustic Recording Packages ( HARPs , Wiggins & Hildebrand 2007) have been collecting acoustic data at...for HARP data is performed using the MATLAB (Mathworks, Natick, MA) based custom program Triton (Wiggins & Hildebrand 2007) and other MATLAB custom...abundance of foraging events throughout the SCB will be quantified. The manual and automatic detection time stamps of both HARP data and acoustic line

  4. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses

    SciTech Connect

    Paffenhofer, G.A.

    1992-09-25

    This study sought to determine and understand the major processes governing the abundance, distribution, composition and eventual fate of zooplankton on the southeastern shelf of the US in relation to water circulation. Over much of the shelf circulation is dominated by the Gulf Stream and/or atmospheric forcing. Most of our studies concentrated on processes on the middle and outer shelf. On the latter, pronounced biological production occurs year-round at frequent intervals and is due to Gulf Stream eddies which move by at an average frequency of one every week. These eddies are rich in nutrients which, when upwelled into the euphoric zone, lead to pronounced primary production which then triggers zooplankton production.

  5. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses. Final report

    SciTech Connect

    Paffenhofer, G.A.

    1992-09-25

    This study sought to determine and understand the major processes governing the abundance, distribution, composition and eventual fate of zooplankton on the southeastern shelf of the US in relation to water circulation. Over much of the shelf circulation is dominated by the Gulf Stream and/or atmospheric forcing. Most of our studies concentrated on processes on the middle and outer shelf. On the latter, pronounced biological production occurs year-round at frequent intervals and is due to Gulf Stream eddies which move by at an average frequency of one every week. These eddies are rich in nutrients which, when upwelled into the euphoric zone, lead to pronounced primary production which then triggers zooplankton production.

  6. Turbulence Observations in the Northern Bight of Monterey Bay from a Small AUV

    NASA Astrophysics Data System (ADS)

    Goodman, Louis; Wang, Zhankun

    2009-06-01

    In this manuscript we show that in shallow water an autonomous underwater vehicle (AUV) can be used to quantify the horizontal and vertical structure of turbulence. We present data obtained during the Layered Organization in the Coastal Ocean (LOCO) experiment, which took place in a very shallow region of Monterey Bay at nighttime in the summer of 2006. The AUV employed was the T-REMUS vehicle, which contains a variety of the microscale and finescale sensors as well as supporting "hotel" sensors which monitor its position and performance. The vehicle was run in a 5-degree yoyo mode and, using the Rockland Microstructure Measurement System (RMMS), was able to obtain direct estimates of the turbulent dissipation rate on a vertical scale of 0.5 m. The yoyo sampling scheme allowed the finestructure and microstructure data to be obtained with an average horizontal sampling distance of 150 m. We examine the spatial structure of turbulence over a horizontal range of 2.5 km and throughout most of the water column, from 1 m from the surface to 4 m above the bottom. Eight hours of such data were collected. The experiment took place during a time period of very light wind forcing, little air sea exchange, and weak tidal flow. Nonetheless, strong turbulence, characterized by a turbulent kinetic energy dissipation rate of ɛ > 10 - 7 W/kg and buoyancy Reynolds number of Reb > 10 3, was observed throughout the experimental region. The turbulence, for the most part, was patchy and typically confined to the surface and bottom boundary layer regions. However, towards the end of the experiment a spatially continuous region of turbulence of at least 2.5 km extent was observed in the upper part of the thermocline. This occurred during the time period when an internal wave train appeared in the experimental area. Evidence is presented which suggests that the internal wave induced vertical strain gradient was responsible for producing this turbulent field.

  7. Annual cyclicity in export efficiency in the inner Southern California Bight

    NASA Astrophysics Data System (ADS)

    Haskell, William Z.; Prokopenko, Maria G.; Hammond, Douglas E.; Stanley, Rachel H. R.; Sandwith, Zoe O.

    2017-02-01

    The balance of marine autotrophy and heterotrophy regulates the ocean's ability to serve as a CO2 sink, as organic material produced by autotrophs sinks into the ocean interior to drive the biological pump. Marine ecosystems over the continental margins, especially coastal upwelling regions, account for a disproportionate amount of carbon export; thus, even small fluctuations in export in these regions can have a large impact on the global carbon cycle. In this study, we estimated the rate of gross oxygen production (GOP), stoichiometrically related to gross primary production, by combining measurements of the triple isotope composition of dissolved oxygen with estimates of vertical advection, eddy diffusion, and air-sea gas exchange in a one-dimensional two-box nonsteady state model of the euphotic zone. Net oxygen production (NOP) estimates based on O2/Ar were then combined with GOP to estimate the NOP/GOP ratio, or potential export efficiency, out of the euphotic zone at the San Pedro Ocean Time-series during an 18 month period between January 2013 and June 2014. GOP estimates ranged from 161 ± 44 to 477 ± 155 mmol m-2 d-1 during this period, peaking in May each year, and NOP/GOP ratios ranged from 0.05 ± 0.10 to 0.65 ± 0.28. The highest export efficiency occurred in late February/early March, following the onset of spring upwelling, declining as the upwelling season continued. This study demonstrates that export efficiency changes through time in this temperate coastal upwelling region on a repeated annual cycle, and the magnitude of export efficiency suggests efficient photosynthetic energy conversion by phytoplankton in spring.

  8. Littoral Transport Modeling for Ocean Beach and San Francisco Bight, California

    DTIC Science & Technology

    2012-07-01

    nourishment for shore and beach protection. The model result can support and improve decision making for regional and local sediment management...Development Center (ERDC) Regional Sediment Management Program (RSM) and Coastal Inlets Research Program (CIRP), and the US Geological Survey (USGS...useful for improving decision making for regional and local sediment management, enhancing cross-mission benefits, and ultimately reducing project life

  9. Seabird use of discards from a nearshore shrimp fishery in the South Atlantic Bight, USA

    USGS Publications Warehouse

    Jodice, Patrick G.; Wickliffe, Lisa C.; Sachs, Elena B.

    2011-01-01

    Shrimp trawling is common throughout the southeastern and Gulf of Mexico coasts of the USA and is the primary contributor to fisheries discards in these regions. Tens of thousands of nearshore seabirds nest near shrimp trawling grounds in the USA, but to date, there has been no assessment of the relationship between seabirds and shrimp trawlers. We examined the taxonomic composition of bycatch, rate at which seabirds scavenged bycatch, and energy density of discarded bycatch in a nearshore commercial shrimp fishery. Bycatch was primarily comprised of demersal fish that are not typically accessible to the plunge-diving and surface-feeding seabirds that occur in the area. Hence, seabird diets in the region appear to be broadened taxonomically by the availability of discards. Results from discard experiments indicated that 70% of the nearly 5,500 items discarded by hand were scavenged by seabirds and that the fate of a discarded item was most strongly predicted by its taxonomic order. Laughing gulls scavenged the greatest proportion of discards, although brown pelicans were the only species to scavenge more discards than predicted based upon their abundance. Because this is the first such study in the region, it is difficult to ascertain the extent or intensity of the impact that discards have on nearshore seabirds. Nonetheless, our results suggest that it will be difficult for managers to clearly understand fluctuations in local seabird population dynamics without first understanding the extent to which these species rely upon discards. This may be especially problematic in situations where seabird populations are recovering following natural or anthropogenic stressors.

  10. Continental shelf processes affecting the oceanography of the South Atlantic Bight

    SciTech Connect

    Atkinson, L.P.

    1990-02-01

    During the past year research activities have focused on analysis and synthesis of existing data from the GALE, FLEX and SPREX experiments and preparation for the WINTER-90 field experiment. The author has also spent some time assisting DOE in planning for the restructuring of the marine program. 8 refs.

  11. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses

    SciTech Connect

    Not Available

    1990-02-07

    The goal of the Fall Removal Experiment 1987 was to determine the processes affecting the dependent and fate of low salinity coastal water and of biological material therein during fall when winds are mainly south-to westward. Five zooplankton taxa, Acartia tonsa, (A. tonsa) Paracalanus species (sp), Temora turbinata (T. turbinata), Oncaea sp, and Sagitta enflata were examined. Data on the distribution of all five taxa were presented, and distribution over time was also studied. The abundance of A. tonsa decreased tenfold over the 13 day sampling period, Paracalanus varied twofold and T. Turbinata showed little variability. The A. tonsa decrease was postulated to result from food abundance or predation, although the possible role of size distribution, water displacement and chlorophyll distribution will be examined in the future. A possible role of turbulence in zooplankton abundance is being examined. 8 refs., 5 figs.

  12. Glider Observations of Sediment Resuspension in a Middle Atlantic Bight Fall Transition Storm

    DTIC Science & Technology

    2008-06-14

    blue lines), Long-term Ecosystem Observatory (LEO) (red circle), the Tuckerton Meteorological Tower (green circle), and the NOAA Delaware Bay weather...summer pycnocline (Beardsley and Boicourt 1981; Biscayne et al. 1994; Castelao et al. 2008). Summertime temperature differences of up to 15uC over depths...the National Oceanic and Atmospheric Association (NOAA) National Data Buoy Center, in particular, Sta. 44009, located offshore of Delaware Bay . Slocum

  13. CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) SOURCE CHARACTERIZATION IN THE LOUISIANA BIGHT

    EPA Science Inventory

    Chromophoric dissolved organic matter (CDOM) in the Mississippi plume region may have several distinct sources: riverine (terrestrial soils), wetland (terrestrial plants), biological production (phytoplankton, zooplankton, microbial), and sediments. Complex mixing, photodegradati...

  14. Hydrologic and Geophysical Constraints on Submarsh Groundwater Flow to an Estuary in the Georgia Bight

    NASA Astrophysics Data System (ADS)

    Fulton, P.; Schultz, G.; Ruppel, C.

    2001-12-01

    Previous research in the Georgia coastal zone suggests that low-permeability muds clog the sediment matrix at the edges of uplands, thereby impeding freshwater flow to the estuary across seepage faces. A significant portion of fresh groundwater flux from upland to estuary may instead occur along intricate submarsh flow pathways. In this study, we combine hydrologic and geophysical measurements to directly constrain submarsh flow pathways and various scales of aquifer heterogeneity beneath a 100-200 m wide Spartina marsh that separates forested upland from a tidal creek at a Long Term Ecological Research (LTER) site on North Sapelo Island. Our data provide both qualitative and quantitative constraints on hydraulic conductivity variations in the marsh sediments. Continuous vibracores (to depths of ~5 m) at the site of our monitoring well network reveal a complex distribution of sediments both vertically and horizontally. In general, the thin, near-surface layer of fine muds gives way to relatively clean sands and then a deeper layer of clay with sand stringers. Where these stringers are laterally continuous, they may serve as critical high permeability conduits for groundwater flow in submarsh sediments. Grain size analyses constrain hydraulic conductivity of the distinct lithologies within the cores, while time and spectral domain analyses of tidal pumping data bracket field-scale hydraulic conductivity near each marsh monitoring well. Our data also allow us to infer information about possible pathways for submarsh groundwater flow. Geophysical surveys (inductive EM and DC resistivity) and borehole conductivity logs suggest a complicated distribution of fresher and more saline pore waters in the submarsh. Preliminary analysis of the geophysical data implies the presence of fresher pore waters at depths of several meters beneath the marsh. A marsh monitoring well within ~10 m of the upland intersects this relatively fresh submarsh flow system. To first order, the density stratification of saline pore waters at shallow levels over fresher water deeper in the marsh should be unstable. We postulate that the persistence of saline over fresher pore waters at this site may imply active flow of the fresher waters along high permeability pathways beneath the marsh.

  15. Age of drifting Macrocystis pyrifera (L.) C. Agardh rafts in the Southern California Bight.

    PubMed

    Hobday

    2000-10-05

    Macrocystis pyrifera plants that detach from the substratum float to the surface and, if they do not become entangled or wash immediately to the shore, may drift at the surface for an unknown period of time. These rafts provide habitat for a variety of coastal and pelagic fauna. The distances dispersed and the period available for species to utilize these habitats, however, depend on the longevity of the raft and methods for determining the age of rafts are unknown. A method to age drifting M. pyrifera rafts based on a change in length of blades (BL) following detachment is validated here. This technique determines the period of time since detachment and not the actual age of the plant. In general, average BL decreases from initial attached values of 50-60 to about 0 cm, when rafts sink. The rate of aging, or deterioration of BL, is related to water temperature, and sets the period a raft stays afloat. Maximal estimates of ages of rafts were between 63 and 109 days, depending on the exact method used. Their lifetime will limit the distances dispersed by kelp rafts in Southern California, and this methodology will be useful for determining the temporal patterns of abundance of fauna associated with rafts.

  16. A Note on Coastally Trapped Waves Generated by the Wind at the Northern Bight of Panama

    DTIC Science & Technology

    2008-01-01

    Stennis Space Center, Mississippi, USA Received June 1, 2007; accepted December 4, 2007 RESUMEN Con el prop6sito de estudiar la formaci6n de una onda ...modelo Navy Layered Ocean Model. Los resultados indican que despu6s de su generaci6n la onda se propaga mAs de 1200 km a lo largo de la costa...incrementando el nivel del mar en mis de 10 cm y generando, a su paso, corrientes costeras superficiales de mAs de 50 cm/s. La ocurrencia de la onda atrapada a

  17. Long-term change in the copepod community in the southern German Bight

    NASA Astrophysics Data System (ADS)

    Boersma, Maarten; Wiltshire, Karen H.; Kong, Sopha-Mith; Greve, Wulf; Renz, Jasmin

    2015-07-01

    The North Sea has undergone considerable change in recent years, with several reported regime shifts in the last decades, the most recent of which is thought to have occurred in the final years of the last century. As biological evidence corroborating this most recent regime shift is still rare, we investigated the reaction of the copepod community of the Helgoland Roads sampling site to this perceived shift. We observed that the densities of calanoid copepods have declined to values which are roughly 25% of the peak densities in the mid 1980s and link the decrease to the decreasing nutrient inputs into the North Sea. The initial increase in the densities of non-calanoid copepods seems to have reversed, and currently most of the copepods of the community in the southern North Sea are below their long-term average. These strong declines in densities could have major consequences for recruitment of higher trophic levels. We expect a stronger dependence of copepod densities to the larger oceanographic phenomena such as inflows of Atlantic water into the North Sea, as now that the large anthropogenic riverine inputs of nitrogen and phosphorus have decreased and these inflows were the main source of nutrients into the North Sea.

  18. Modelling physical-biological interactions in the Southeast Brazil Bight: transport patterns of Brazilian Sardine larvae

    NASA Astrophysics Data System (ADS)

    Faggiani Dias, D.; Gherardi, D. F.; Pezzi, L. P.

    2013-05-01

    The advection of Brazilian Sardine (Sardinella brasiliensis) eggs and larvae in the SBB was modeled using an individual-based model (Ichthyop) and a hydrodynamic model (Regional Ocean Modeling System, ROMS) to test for differences in larval retention for five spawning areas with high probability of egg occurrence: i) two areas north of the domain - Cape Frio and Rio de Janeiro, ii) one in the middle in Sao Sebastiao, and iii) two in the South in Paranagua. According to previous studies, this encompasses the known spawning habitat. Advective processes and physical characteristics, such as water temperature and salinity, were considered to determine larvae transport and survival. The hydrodynamic model grid has a horizontal resolution of 1/12o. Results of monthly mean Sea Surface Temperature (MSST) and Sea Surface Height (MSSH) indicate there isn't warming or cooling trend over the years, and the seasonal cycle well represented. These results were compared with satellite-derived data from the AVHRR sensor and AVISO project. Model results accurately represent the position and shape of the main surface structures observed in the satellite data. Monthly MSST maps for the experiment period indicate that the model tends to underestimate temperatures in upwelling areas and overestimate in the Brazil Current region, with differences mostly around ±1oC. For MSSH, although the model represents well the main surface ocean structures, it tends to underestimate along the domain. Temperature-salinity diagrams plotted in a coastal area for December of four years (1985, 1986, 1987 and 1988), near Ubatuba region, are consistent with field collected data, suggesting that the main water masses in SBB are reliably represented. The IBM experiments were carried out during the summer of six years (1980, 1981, 1988, 1991, 1992 and 1993). For each year, 20000 eggs were released, distributed in the five areas, and tracked for 45 days. At the end of simulation, the mortality due to temperature and advection, the coastal retention and the larvae survival were calculated. These variables were tested with a non-parametric variance (Kruskall-Wallis) analysis (95%) for differences among the five spawning areas. For the advection variable, the offshore area was the only one considered that significantly segregated the different areas, with 99% of the larvae advected out of domain. On the other hand, the other four areas weren't considered significantly different for the tested variables. Nevertheless, the largest survival rate was found in Cape Frio, where typical summer upwelling can contribute to larvae survival. The intrusion of the South Atlantic Coastal Water in the shelf generates a stable thermocline and supplies nutrients input, providing a more suitable area for larvae development. Besides, in this area, the Brazil Current is closer to the coast with the occurrence of a subsurface density front. These physical processes can also contribute to larvae survival as they increase larval retention near the coast, avoiding unfavorable environments. This is a pioneering study using physical-biological models in SBB and it helps understand the Brazilian Sardine spawning dynamics in a more realistic way.

  19. Coastal SAR and PLRM Altimetry in German Bight and West Baltic Sea

    NASA Astrophysics Data System (ADS)

    Dinardo, Salvatore; Fenoglio-Marc, Luciana; Buchhaupt, Christopher; Scharroo, Remko; Fernandes, M. Joana; Benveniste, Jerome; Becker, Matthias

    2016-08-01

    The CryoSat-2 altimeter (SIRAL) features a novel Synthetic Aperture Radar (SAR) mode that allows higher resolution and more accurate altimeter-derived parameters in the coastal zone, thanks to the reduced along-track footprint.This study is a regional analysis and validation of CryoSat-2 SAR altimeter products along the German coasts at distance to shore smaller than 10 km. The validation in performed against regional models and an in-situ network of tide gauges and Global Navigation Satellite Systems (GNSS) stations. The goal is an assessment of the geophysical altimeter parameters sea surface height above the ellipsoid (SSH), significant sea wave height (SWH) and wind speed (U10), all estimated at 20 Hz over the time interval from October 2010 to July 2015.We have carried out from FBR (L1a) data a Delay- Doppler processing and waveform retracking tailored to coastal zone by a dedicated SAMOSA-based coastal retracker (SAMOSA+). SAMOSA+ accepts mean square slope as free parameter and the epoch's first guess fitting value is decided according to the peak in correlation between 20 consecutive waveforms to reduce land off-ranging effects.Since the remaining uncertainty in the altimeter products for coastal shallow waters arises mainly from residual errors in the applied corrections, we use the regional model TPXO8 for tides, EGM 2008 for geoid and DTU13 for mean sea surface and the regionally improved wet tropospheric correction GNSS-based Path Delay Plus (GPD+) computed at University of Porto.To quantify the improvement with respect to pulse- limited altimetry, we build 20 Hz PLRM (pseudo-LRM) data from FBR as a proxy for real pulse-limited products (LRM). They are retracked with a numerical Brown-based retracker. The L2 SAR ocean data products are generated and extracted from ESA-ESRIN GPOD service (named SARvatore) while the PLRM data are built and retracked by Technical University of Darmstadt (TUDa).The validation shows that the accuracy of sea level in coastal zone is higher in SAR than in PLRM and that is comparable to the accuracy of SAR in open sea until 3km from coast. The standard deviations of sea level difference with in-situ data in open ocean and coastal zone are 4.1 cm and 5.1 cm respectively.

  20. Enigmatic sediment ridges in the German Bight - glacial vs post-glacial morphologies?

    NASA Astrophysics Data System (ADS)

    Unnithan, Vikram; Pio Rossi, Angelo; Praeg, Daniel

    2014-05-01

    The German Wadden Sea extends over 1000 km from the Dutch coast to that of Sweden and consists of a long chain of barrier islands and ephemeral sand banks punctuated by estuaries and rivers. The sedimentary environment is currently shaped and characterised by storm surges, high tidal and wave energy levels. However, this part of the North Sea has been repeatedly covered by continental ice sheets, and it remains unclear how glacial to interglacial sedimentary processes may have influenced seabed morphology in the region. The study area is situated approximately 70 km north of Cuxhaven, and 5 km due east of the islands of Helgoland and Dune. It covers an approximate area of 5 km square with water depths ranging from 50 m in the south to about 20 m in the north. High resolution multibeam (Simrad EM710) and parametric echosounder (Innomar SES2000) data were acquired during graduate and undergraduate teaching excursions on the RV Heincke in Spring 2010 (HE-324) and 2011 (HE-349). The seabed swath bathymetric data reveal distinctive linear seabed ridges. The ridges trend NNW-SSE, are 1-5 m in height, have wavelengths on the order of 100 m and crest lengths ranging from 100-2500 m. The ridge crests are broadly anastomosing. They bifurcate towards the north to form more subdued structures, while they converge and disappear to the south. Profiles across the ridges show an asymmetric structure, with steeper slopes trending west in the western part of the study area but trending east in the eastern part. These enigmatic sedimentary structures have not been previously mapped in the Wadden Sea, and their origin remains uncertain. Possible interpretations to be tested include sub-crop structural control on seabed morphology, relict glacial or glaciofluvial landforms and post-glacial marine bedforms linked to processes of sediment redistribution.

  1. Ecological and political issues surrounding decommissioning of offshore oil facilities in the Southern California Bight

    USGS Publications Warehouse

    Schroeder, Donna M.; Love, Milton S.

    2004-01-01

    To aid legislators, resource managers, and the general public, this paper summarizes and clarifies some of the issues and options that the federal government and the state of California face in decommissioning offshore oil and gas production platforms, particularly as these relate to platform ecology. Both local marine ecology and political climate play a role in decommissioning offshore oil production platforms. Compared to the relatively supportive political climate in the Gulf of Mexico for “rigs-to-reefs” programs, conflicting social values among stakeholders in Southern California increases the need for understanding ecological impacts of various decommissioning alternatives (which range from total removal to allowing some or all of platform structure to remain in the ocean). Additional scientific needs in the decommissioning process include further assessment of platform habitat quality, estimation of regional impacts of decommissioning alternatives to marine populations, and determination of biological effects of any residual contaminants. The principal management need is a ranking of environmental priorities (e.g. species-of-interest and marine habitats). Because considerable numbers of economically important species reside near oil platforms, National Oceanic and Atmospheric Administration Fisheries should consider the consequences of decommissioning alternatives in their overall management plans. Management strategies could include designating reefed platforms as marine protected areas. The overarching conclusion from both ecological and political perspectives is that decommissioning decisions should be made on a case-by-case basis.

  2. Interannual variability of sorted bedforms in the coastal German Bight (SE North Sea)

    NASA Astrophysics Data System (ADS)

    Mielck, F.; Holler, P.; Bürk, D.; Hass, H. C.

    2015-12-01

    Sorted bedforms are ubiquitous on the inner continental shelves worldwide. They are described as spatially-grain-size-sorted features consisting of small rippled medium-to-coarse sand and can remain stable for decades. However, the knowledge about their genesis and development is still fragmentary. For this study, a representative investigation area (water depth<15 m) located on the shelf west of the island of Sylt (SE North Sea, Germany) was periodically surveyed with hydroacoustic means (i.e. sidescan sonar, multibeam echo sounder, and sub-bottom profiler) during 2010-2014. Since this area is influenced by tidal and wind-driven currents, the aim was to detect and examine interannual variabilities in the characteristics of the prevailing sorted bedforms. Our measurements reveal sinuous stripes of rippled medium sand which are embedded in shallow symmetrical depressions. These domains are surrounded by relatively smooth fine-sand areas. These sorted bedforms were identified as flow-transverse features that are maintained by ebb and flood currents of almost equal strengths that flow in opposite directions. This bidirectional flow field generates sharp boundaries between the medium- and fine-sand domains in both current directions. Further to the north, where flood currents are dominant, asymmetric sorted bedforms were detected which show sharp boundaries only in flood-current direction. Comparisons between the measurements of the different years show no significant variations in morphology and distribution of the sorted bedforms. However, variations of the boundaries between the medium and the fine-sand domains were observed. Additionally, new minor sorted bedforms and rippled excavation marks as well as new fine-sand areas developed and disappeared occasionally. It can be supposed that such sediment winnowing and focusing processes take place during periodically recurring storm surges, which change the shapes of the features. Moreover, variations in alignments and sizes of the small ripple formations were detected. They seem to indicate the directions and intensities of previous storm events.

  3. Occurrence of Vibrio parahaemolyticus and Vibrio alginolyticus in the German Bight over a seasonal cycle.

    PubMed

    Oberbeckmann, Sonja; Wichels, Antje; Wiltshire, Karen H; Gerdts, Gunnar

    2011-08-01

    Bacteria of the genus Vibrio are an important component of marine ecosystems worldwide. The genus harbors several human pathogens, for instance the species Vibrio parahaemolyticus, a main cause for foodborne gastroenteritis in Asia and the USA. Pathogenic V. parahaemolyticus strains emerged also in Europe, but little is known about the abundance, pathogenicity and ecology of V. parahaemolyticus especially in Northern European waters. This study focuses on V. parahaemolyticus and its close relative Vibrio alginolyticus in the North Sea (Helgoland Roads, Germany). Free-living, plankton-attached and shellfish-associated Vibrio spp. were quantified between May 2008 and January 2010. CFUs up to 4.3 × 10(3) N l(-1) and MPNs up to 240 N g(-1) were determined. Phylogenetic classification based on rpoB gene sequencing revealed V. alginolyticus as the dominant Vibrio species at Helgoland Roads, followed by V. parahaemolyticus. We investigated the intraspecific diversity of V. parahaemolyticus and V. alginolyticus using ERIC-PCR. The fingerprinting disclosed three distinct groups at Helgoland Roads, representing V. parahaemolyticus, V. alginolyticus and one group in between. The species V. parahaemolyticus occurred mainly in summer months. None of the strains carried the virulence-associated genes tdh or trh. We further analyzed the influence of nutrients, secchi depth, temperature, salinity, chlorophyll a and phytoplankton on the abundance of Vibrio spp. and the population structure of V. parahaemolyticus. Spearman Rank analysis revealed that particularly temperature correlated significantly with Vibrio spp. numbers. Based on multivariate statistical analyses we report that the V. parahaemolyticus population was structured by a complex combination of environmental parameters. To further investigate these influences is the key to understanding the dynamics of Vibrio spp. in temperate European waters, where this microbial group and especially the pathogenic species, are likely to gain in importance.

  4. Modeling of Habitat and Foraging Behavior of Beaked Whales in the Southern California Bight

    DTIC Science & Technology

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. FINAL REPORT Modeling of Habitat and Foraging Behavior of...whale distribution and foraging behavior and to describe inter-specific differences. We investigated spatio-temporal patterns for Cuvier’s beaked whale...distribution and foraging behavior and to describe inter-specific differences. Knowledge about foraging behavior and habitat preference and

  5. Canyon and channel networks of Peru-Chile fore arc at Arica Bight

    SciTech Connect

    Coulbourn, W.T. )

    1990-05-01

    Canyons and channels of the Peru-Chile fore arc between 17{degree}30'S to 19{degree}30'S form a complex, integrated network revealed in SeaMARC II side-scan mosaics. The largest canyon, incised 200-600 m, is bordered by a series of sidewall slumps, producing a sinuosity that mimics subaerial meanders. The canyon courses across the Arequipa fore-arc basin floor, across a structural high and onto the middle trench slope to about 4,000 m where it disappears into a background of complex small-scale structures, From 500-2,500 m depth the canyon strikes north-south oblique to the regional slope. At 2,500 m, it abruptly turns to the southwest toward the trench axis. At this elbow, a second canyon heads on the midslope and also trends north-south until 3,500 m, where it too abruptly changes to a southwest course. A history of stream piracy analogous to subaerial systems is implied in this geometry. Tributaries join this main canyon from the landward side, forming a dendritic pattern. These channels have levees which are linked by submarine crevasse splays to sediment waves on the Arequipa basin floor. The orientation of the waves is reminiscent of bow waves from a passing ship, oblique to channel and pointing downslope, and may provide an indication of the vertical extent of passing turbidity currents. Sediments are dominantly olive gray, hemipelagic silts with sands present only immediately adjacent to the canyons. Boulders of mudstone line portions of the canyon floor. Sands are absent from the lowermost slope and trench axis, as are any indications of submarine fans. Sands may be rare in this system, with those that are present kneaded into the active margin system along the lower trench slope.

  6. Modeling of Habitat and Foraging Behavior of Beaked Whales in the Southern California Bight

    DTIC Science & Technology

    2014-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Modeling of Habitat and Foraging Behavior of Beaked Whales ...N00014-12-1-0273 http://baumann.ucsd.edu LONG-TERM GOALS The overall goal of this project is to improve our understanding of beaked whale ...distribution and foraging behavior and to describe inter-specific differences. We are developing habitat models for multiple beaked whale species in the

  7. Biological processes in the water column of the South Atlantic Bight: Phytoplankton response: A three-year progress report

    SciTech Connect

    Verity, P.G.; Yoder, J.A.

    1987-12-01

    This project report consists of published and unpublished manuscripts which describe research studies initiated and completed during the past three years. Results of these and additional efforts, presently being prepared for submission to refereed journals, were presented at various scientific meetings. SPREX was an interdisciplinary study of the spring removal period when low salinity nearshore waters advect offshore in the region between Savannah and Cape Fear. Our objectives were to determine the fate of the relatively high concentrations of phytoplankton biomass within low salinity nearshore waters and to determine the effect of wind events on phytoplankton dynamics within the nearshore zone. All field studies are complete, and a workshop was held in March 1986 to provide a forum for all investigators to discuss and interpret the results. Several related studies on plankton dynamics in coastal and shelf waters are in progress. A new component, research on the abundance, distribution, and impact of protozoan grazers, was added to this project in 1986 to 1987. Data collection in the nearshore program (BIOTRANS) is nearing completion. Synthesis and analysis of data are in progress. Research on shelf processes includes two components: interdisciplinary shipboard efforts (FLEX) and studies of CZCS satellite imagery of chlorophyll distributions. 6 figs., 1 tab.

  8. Airborne synthetic aperture radar observations of “spiral eddy” slick patterns in the Southern California Bight

    NASA Astrophysics Data System (ADS)

    Marmorino, George O.; Holt, Benjamin; Molemaker, M. Jeroen; Digiacomo, Paul M.; Sletten, Mark A.

    2010-05-01

    Repeat sampling on hourly time scales using an airborne synthetic aperture radar (SAR) is used to investigate the occurrence and evolving characteristics of spiral-shaped slick patterns, commonly presumed to be indicators of submesoscale ocean eddies, in the area around Santa Catalina Island, California (˜33.4°N, 118.4°W). Simultaneous SAR imagery and boat survey data are examined over two ˜5 h long periods spaced 3 days apart in April 2003. The SAR imagery reveals several spiral-like patterns, roughly 5 km in diameter, occurring downstream of the western end of Catalina. We believe that the most likely formation mechanism for these patterns is current-wake instability related to the flow of the Southern California Countercurrent along the north shore of Catalina. In one case, there is an observed cold-core eddy and vortex sheet attached to the tip of the island, similar to island-wake simulations done by Dong and McWilliams (2007). In another case, the SAR imagery shows a series of slick patterns that, at least initially, resemble spiral eddies, but the data show no clear evidence of actual ocean eddies being present either at depth or through a rotating surface expression. A speculation is that such features signify island-wake eddies that are relatively weak and dissipate quickly. An unexpected finding was how quickly a spiral slick pattern could deteriorate, suggesting a time scale for the surface feature of the order of only several hours. An implication of this result is that care is needed when interpreting a single satellite SAR imagery for evidence of active submesoscale eddies. Recommendations are made for future field studies.

  9. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses: Progress report, June 1988--June 1989

    SciTech Connect

    Paffenhoefer, G.A.

    1989-02-07

    It is our objective to determine the major processes governing the abundance, composition and disruption of zooplankton as part of the interdisciplinary southeastern US continental shelf program of the Department of Energy. We will study the effects of physical processes such as along- and cross shelf advection and frontogenesis, on the development and fate of zooplankton populations during winter. Our proposed research consists of shipboard sampling, laboratory experiments and in situ determination of zooplankton abundance over time. The last objective represents a novel approach because the observations are (a) non-destructive with great spatial resolution, and (b) occur on current meter arrays at similar scales as measurements of current velocity and direction. Results to date show prolonged residence times of upwelled water masses on the middle and inner shelf during summer which results in the development of massive copepod and tunicate populations. During spring, the extent of displacement of nearshore zooplankton was a function of wind stress. Our results can be used to predict the impact of energy-related technology on the ecosystem of the southeastern continental shelf. 8 refs., 6 figs.

  10. Cool-water carbonate sedimentology and eustasy; Pleistocene upper slope environments, Great Australian Bight (Site 1127, ODP LEG 182)

    NASA Astrophysics Data System (ADS)

    Betzler, C.; Saxena, S.; Swart, P. K.; Isern, A.; James, N. P.

    2005-04-01

    The southern Australian shelf is the largest area of the globe composed of cool-water carbonates and provides the basis for the development of actualistic models of such sediments. Ocean Drilling Program Leg 182 drilling of the sedimentary succession provides essential information to also decipher the dynamics of this depositional system. Sediment samples and geophysical logs from a core drilled on the Eucla Plateau off the coast of southern Australia (Site 1127) have been used to study sedimentary cyclicity in an 800-m-thick cool-water carbonate Pleistocene wedge. This periplatform succession is dominated by bioclastic packstone and wackestone with minor intercalations of bioclastic grainstone. Fluctuations of stable oxygen-isotope values in bulk carbonate samples parallel global climatic and related sea-level fluctuations as predicted in the SPECMAP-curve. The sea-level-controlled sedimentary cycles of the slope succession are several tens of meters thick. Lowstand deposits are relatively fine grained and include abundant sponge spicules, whereas highstand deposits are coarser grained and contain abundant high-Mg calcite bioclasts. Aragonite content makes up to 36% of the cool-water carbonates. Aragonite originates from tunicate spicules. Primary, sea-level-controlled carbonate mineralogical and textural changes are likely to promote facies-dependent differential diagenesis during later burial stages of such successions.

  11. Utilizing geological and geotechnical parameters to constrain optimal siting of Mid-Atlantic Bight offshore wind projects

    NASA Astrophysics Data System (ADS)

    Ponte, Alia

    As the offshore wind energy sector expands due to government mandates, a thorough understanding of the geologic setting of potential project sites becomes an essential component in the design process. Geophysical and geotechnical parameters yield vital information on the sediments and/or rocks that are present. The variable distribution of sediments, with concomitant variations in geotechnical properties, has significant implications for the selection (e.g., monopile, suction caisson, gravity base, jacket), design, location, installation, and subsequent scouring in the vicinity of wind turbine foundations. Identifying suitable sites based on sediment types allow for optimized engineering design solutions. Because foundations represent approximately 25% of total offshore wind project expenditures, reducing foundation costs with geologic suitability in mind could significantly decrease required initial investments, thereby expediting project and industry advancement. To illustrate how geological and geotechnical data can be used to inform site selection for foundations, geophysical data were analyzed and interpreted (chirp sub-bottom profiling, side-scan sonar, and multibeam bathymetry) from the Maryland Wind Energy Area (WEA). Side-scan sonar data from the WEA show three distinct acoustic intensities; each is correlated to a general bottom sediment grain size classification (muds, muddy and/or shelly sand, and sand with some gravel). Chirp sub-bottom profiles reveal the continuity and thicknesses of various depositional layers including paleochannel systems. Paleochannels consist of heterogeneous infill; creating undesirable conditions for foundation placement. This "desktop" study provides a suitability model for how the interpretation of geophysical and geotechnical data can be used to provide constraints on, and reduce uncertainties associated with, foundation location and type selection. Results from this study revealed 5 distinct subsurface units. The oldest (Unit 5) originated from Middle Pleistocene during Marine Isotope Stages (MIS) 5 & 6. The youngest (Unit 1) consists of the modern surficial sand sheet sediments which have been eroded and reworked during recent Holocene transgression. Several distinct paleochannel systems incise the study area. Though data beyond the boundaries of the study area are scarce a southeasterly channel direction along with results from previous studies suggest these systems originated from Maryland coastal bays. An integrated marine spatial planning approach identified the southernmost portions of the study area as the most unsuitable for wind energy development. Conversely, the same analysis determined that the central-eastern section of the WEA is most suitable. Correlating these data with parameters governing foundation selection revealed that piled-type foundations (either lattice or monopile) are most appropriate for the study area, although suction bucket caisson foundations cannot be definitely ruled out as a possible design solution.

  12. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic Bight): Atlantic and shortnosed sturgeons

    SciTech Connect

    Gilbert, C.R. )

    1989-12-01

    Species profiles are literature summaries of the taxonomy, morphology, range, life history, and environmental requirements of coastal species. The Atlantic and shortnose sturgeons (especially the former) were commercially important fishes between 1880 and 1900, but stocks have since decreased markedly and the shortnose sturgeon is now classified as federally endangered. Although the two species are anadromous, the shortnose sturgeon tends to spawn farther upstream, and spawning in both species usually occurs over a clean, hard substrate washed by a moderate to strong current. The shortnose sturgeon usually spawn earlier at the same latitude, with spawning of this species in the St. John River, New Brunswick, being completed by mid-May, as opposed to late June or even July for the Atlantic sturgeon. During non-spawning periods, the shortnose is largely confined to estuaries and apparently does not undergo the extensive coastal migrations that are characteristic of the Atlantic sturgeon. Atlantic sturgeon mature more slowly than shortnose sturgeon at comparable latitudes, with male and female Atlantic sturgeon from the Hudson River, New York, requiring at least 11 and 18 years, respectively, to reach maturity, compared with less than half that time for the shortnose sturgeon. Spawning in both sexes may occur thereafter only once every several years. Both species are usually indiscriminate feeders and feed by sucking materials off the bottom with their protrusible mouths. Feeding apparently occurs mostly at night in the shortnose sturgeon. 71 refs., 14 figs., 1 tab.

  13. Biological processes in the water column of the South Atlantic Bight. Progress report, June 1982-June 1984

    SciTech Connect

    Paffenhofer, G.A.; Yoder, J.A.

    1983-12-01

    Research has been directed toward understanding phytoplankton dynamics and related processes in nearshore waters. This report summarizes work on the limitation of phytoplankton growth by nutrients in nearshore waters, the inhibition of the rate of phytoplankton production by wind and tide-induced vertical mixing within the turbid nearshore waters, the influence of the coastal frontal zone on the spatial distributions of phytoplankton biomass, primary production and plant nutrients, and zooplankton abundance, distribution and production in relation to hydrographic variables. (ACR)

  14. Biological processes in the water column of the South Atlantic Bight: zooplankton responses. Progress report, June 1985-June 1986

    SciTech Connect

    Paffenhoefer, G.A.

    1985-12-20

    The effects of wind forcing on water displacement from the near- to the offshore environment of the southeastern continental shelf are discussed. This report presents information on zooplankton abundance and distribution in relation to hydrographic variables. 7 figs. (ACR)

  15. Nematode assemblages from subtidal sandbanks in the Southern Bight of the North Sea: effect of small sedimentological differences

    NASA Astrophysics Data System (ADS)

    Vanaverbeke, Jan; Gheskiere, Tom; Steyaert, Maaike; Vincx, Magda

    2002-11-01

    Nematode assemblages from four subtidal sandbanks belonging to different sandbank systems on the Belgian Continental Shelf were investigated both in spring and fall. The assemblages were characterised by different species composition patterns on the different sandbanks. This is in contrast to results of earlier studies which showed that neither meiobenthic nor macrobenthic taxa differed among these sandbanks. Although the sediments on these sandbanks could all be classified as medium sands, the use of Multiple Discriminant Analysis (MDA) suggested that median grain size and the proportions of median sand and very fine sand were the variables explaining the difference in nematode community composition. These findings emphasise the strong relationship between the relative abundance of nematode species and sediment composition. The influence of sand extraction on these sandbanks resulted in coarsening of the sediment, which had a direct effect on the nematode species composition. Diversity was not affected, indicating that nematodes inhabiting highly dynamic environments are well adapted to physical disturbance. The diversity at sandbanks is not necessarily very different from the surrounding areas, since in more offshore parts of the Belgian Continental Shelf, clean and rather coarse sands prevail and the differences in sediment composition are not sufficient to induce large differences in diversity.

  16. The sedimentary architecture of a Holocene barrier spit (Sylt, German Bight): Swash-bar accretion and storm erosion

    NASA Astrophysics Data System (ADS)

    Lindhorst, Sebastian; Betzler, Christian; Hass, H. Christian

    2008-04-01

    The southern German North Sea coast was shaped by the last post-glacial sea-level rise that caused a significant retreat of the coastline. Approximately 5 ka BP, the rate of sea-level rise decreased, providing space for the formation of the Frisian Islands which line the coast. This study is focused on the island of Sylt, located at the German North Sea coast close to the Danish border. Here, two sandy spit systems developed during the Holocene. Combining ground-penetrating radar studies and sedimentological investigations based on shallow cores, new aspects on the sedimentary history of this Holocene spit system have been revealed. The data indicate that strong erosional events alternated with phases of progradation and growth. The welding of swash bars is shown to be the predominant process during progradational phases of the spit system. During these periods, progradation was not restricted to linear growth along the spit axis, but also included a seaward-directed component. Major erosion surfaces, which delimit progradational sediment packages, are interpreted to reflect exceptionally severe storms. The fossilization potential of this sedimentary record was controlled by a positive net long-term sediment balance and the position of the ground-water table which controlled eolian deflation. Only with a stable or rising sea level and associated ground-water table position are sediments protected from deflation. The proposed sedimentary model may serve as a template for interpretation of comparable settings in the geological record.

  17. The macrofauna and macroflora associated with Laminaria digitata and L. hyperborea at the island of Helgoland (German Bight, North Sea)

    NASA Astrophysics Data System (ADS)

    Schultze, Kirstin; Janke, Klaus; Krüß, Andreas; Weidemann, Wolfgang

    1990-03-01

    This paper describes the macroflora and macrofauna associated with two bull kelp species, Laminaria hyperborea and L. digitata, at the island of Helgoland, North Sea. During a study period of seven months (March September 1987), 29 macroflora species and 125 macrofauna species were found. The dominant taxonomic groups were Polychaeta (25 species), Bryozoa (17), Amphipoda (14), Hydrozoa (10) and Ascidiae (8). The species maximum was in July. In general, L. hyperborea was preferred as a substrate for settlement to L. digitata. Composition of the communities associated with kelp changed during the season according to exposure to wave action, and according to location on the kelp thallus. The rhizoid community of both kelps bore more species at exposed locations. Wave-exposed L. digitata lacked obvious faunal settlement on both phylloid and cauloid. Phylloid and cauloid of L. hyperborea were chosen as an attractive substrate at both sheltered and wave-exposed locations, showing an association of encrusting bryozoan and hydrozoan colonies.

  18. Karyological and gonadal sex of eels (Anguilla anguilla) from the German Bight and the lower River Elbe

    NASA Astrophysics Data System (ADS)

    Passakas, T.; Tesch, F.-W.

    1980-06-01

    Yellow eels (Anguilla anguilla) taken during summer from random commercial trapnet samples in the littoral area of Helgoland (n=116) and from a freshwater area of the River Elbe near Hamburg (n=109) were examined with regard to their karyological (i.e. existence of female sex chromosomes) and gonadal sex. In 47 % and 21 % of the two samples, respectively, chromosomes were unidentifiable because of insufficient numbers of mitotic plates. All eels from Helgoland, except one phenotypically undetermined fish, exhibited female gonads: 48 had female sex chromosomes and 13 were karyologically males. As found previously in the River Elbe, eels with male gonads predominated (n=55); 25 were undifferentiated. Of the gonadal males 26 were karyological males and 16 karyological females; the rest could not be identified by chromosome patterns. In contrast, all but one of the Elbe eels with female gonads (n=28) had female sex chromosomes. Some aspects of the sex reversal documented in the eel are considered.

  19. Analysis of High Spatial, Temporal, and Directional Resolution Recordings of Biological Sounds in the Southern California Bight

    DTIC Science & Technology

    2014-09-30

    Ocean Science curricular group at SIO this past year. She initially was interested in the underwater sounds created by fish and invertebrates , with...specific fish and invertebrate species 3 (e.g., the species of fish creating the chorus discussed in D’Spain et al., 2013 has not yet been identified

  20. Biomarkers of peat-forming plants and their signal in tidal flat sediments of the german bight

    NASA Astrophysics Data System (ADS)

    Wöstmann, R.; Köller, C.; Rullkötter, J.

    2003-04-01

    Induced by the Holocene sea level rise a number of different peat layers developed in the surface of today´s Wadden Sea of NW Germany. Furthermore, lipid analysis of Wadden Sea sediments showed a significant component of terrestrial organic matter derived from erosion of peat layers in this highly dynamic area. In order to characterise these peats and their remnants in tidal flat sediments in a paleochemotaxonomical way, recent plant material as well as different types of peats were selected for biomarker investigation. Recent plant material was linked paleochemotaxonomically to deposited peats and Wadden Sea sediments by means of selected biomarkers. A significant variation of the n-alkane distribution pattern between raised bog plants and fen plants was detected. The raised bog plants showed an n-alkane maximum at n-C31, the fen plants at n-C27 and n-C29. This is in agreement with results of the botanical and geochemical analysis of different types of Holocene peat layers in this area. In the selected Wadden Sea sediment core the n-alkane distribution showed an odd over even carbon number predominance with maxima at n-C27, n-C29 or n-C31, indicating an origin from different peat types. In addition, pentacyclic triterpenoids are characteristic biomarkers for bog and fen plant communities. Their distribution patterns and total amounts allow a clear distinction between raised-bog-forming plants and fen-peat-forming plants. Whereas all analysed fen-peat-forming plants were barren of triterpenoids, raised-bog-forming plants like Erica tetralix contain triterpenoids at a level of more than 10% of the total lipid extract. All other bog-forming plants also contain high amounts of triterpenoids like a-amyrin, ß-amyrin, friedelin, lupeol, multiflorenon and taraxerol. However, individual triterpenoids are not plant-specific biomarkers because of possible diagenetic effects. When triterpenoids are found in fen peats they are due to the influence of non-peat-forming plant material like birch trees (betula sp.) which supply, e.g., betulin. Most of the investigated sediment core samples showed a high concentration of betulin and lupeol, which demonstrates the significance of organic matter from trees of the Betulaceae family. The distributions of characteristic biomarkers shows that the molecular composition of peat-forming plants corresponds to that of the lipid extracts from Wadden Sea sediments. These data attest to the importance of recycled ancient organic material in the carbon cycle of this coastal environment. The results are complementary to the microscopic paleobotanical analysis and highly specific.

  1. Evaluation of two algorithms for a network of coastal HF radars in the Mid-Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Kohut, Josh; Roarty, Hugh; Randall-Goodwin, Evan; Glenn, Scott; Lichtenwalner, C. Sage

    2012-06-01

    The National High Frequency (HF) Surface Current Mapping Radar Network is being developed as a backbone system within the U.S. Integrated Ocean Observing System. This paper focuses on the application of HF radar-derived surface current maps to U.S. Coast Guard Search and Rescue operations along the Mid-Atlantic coast of the USA. In that context, we evaluated two algorithms used to combine maps of radial currents into a single map of total vector currents. In situ data provided by seven drifter deployments and four bottom-mounted current meters were used to (1) evaluate the well-established unweighted least squares (UWLS) and the more recently adapted optimal interpolation (OI) algorithms and (2) quantify the sensitivity of the OI algorithm to varying decorrelation scales and error thresholds. Results with both algorithms were shown to depend on the location within the HF radar data footprint. The comparisons near the center of the HF radar coverage showed no significant difference between the two algorithms. The most significant distinction between the two was seen in the drifter trajectories. With these simulations, the weighting of radial velocities by distance in the OI implementation was very effective at reducing both the distance between the actual drifter and the cluster of simulated particles as well as the scale of the search area that encompasses them. In this study, the OI further reduced the already improved UWLS-based search areas by an additional factor of 2. The results also indicated that the OI output was relatively insensitive to the varying decorrelation scales and error thresholds tested.

  2. Multiple Stressors at the Land-Sea Interface: Cyanotoxins at the Land-Sea Interface in the Southern California Bight

    PubMed Central

    Tatters, Avery O.; Howard, Meredith D.A.; Nagoda, Carey; Busse, Lilian; Gellene, Alyssa G.; Caron, David A.

    2017-01-01

    Blooms of toxic cyanobacteria in freshwater ecosystems have received considerable attention in recent years, but their occurrence and potential importance at the land-sea interface has not been widely recognized. Here we present the results of a survey of discrete samples conducted in more than fifty brackish water sites along the coastline of southern California. Our objectives were to characterize cyanobacterial community composition and determine if specific groups of cyanotoxins (anatoxins, cylindrospermopsins, microcystins, nodularins, and saxitoxins) were present. We report the identification of numerous potentially harmful taxa and the co-occurrence of multiple toxins, previously undocumented, at several locations. Our findings reveal a potential health concern based on the range of organisms present and the widespread prevalence of recognized toxic compounds. Our results raise concerns for recreation, harvesting of finfish and shellfish, and wildlife and desalination operations, highlighting the need for assessments and implementation of monitoring programs. Such programs appear to be particularly necessary in regions susceptible to urban influence. PMID:28282935

  3. Small scale patches of suspended matter and phytoplankton in the Elbe River estuary, German Bight and tidal flats

    NASA Technical Reports Server (NTRS)

    Doerffer, R.; Fischer, J.; Stoessel, M.; Brockmann, C.; Grassl, H.

    1989-01-01

    Landsat 5 TM measurements are found suitable for study of small scale features in coastal waters; three independent factors, namely suspended matter concentration, atmospheric scattering, and sea-surface temperature, were extracted from all seven TM channels on the basis of factor analysis. The distribution of suspended matter in near-surface water layer and sea surface temperature is observable with a spatial resolution of at least 120 x 120 sq m. The high correlation between water depth and suspended matter distribution established by ship-gathered data supports the presently hypothesized control by bottom topography and wind-modified tidal currents of eddy and front formation.

  4. Analysis of High Spatial, Temporal, and Directional Resolution Recordings of Biological Sounds in the Southern California Bight

    DTIC Science & Technology

    2013-09-30

    set continued, requiring minimal effort since the processing software was developed in the first year . Copies of the remaining unclassified data were...Ancillary and oceanographic data for the temporal and spatial attributes of the data set were gathered in the first year of this program and...program was on the biological sounds at low to mid frequencies recorded during a large experiment off the southern California coast in 1999. The efforts

  5. Numerical Investigation of the Middle Atlantic Bight Shelfbreak Frontal Circulation Using a High-Resolution Ocean Hindcast Model

    DTIC Science & Technology

    2010-05-01

    N. Flagg, 1976: The water structure, mean currents, and shelf/slope water front on the New England continental shelf. Mem Soc. Roy. Sci. Liege , 6...C06003, doi:10.1029/ 2005JC003116. Flather, R. A., 1976: A tidal model of the northwest European continental shelf. Mem. Soc. Roy. Sci. Liege , 6

  6. 210Pb balance and implications for particle transport on the continental shelf, U.S. Middle Atlantic Bight

    USGS Publications Warehouse

    Bacon, M.P.; Belastock, Rebecca A.; Bothner, Michael H.

    1994-01-01

    Supply of 210Pb to the continental shelf off the northeastern United States is dominated by the deposition from the atmosphere, the rate of which is reliably known from previously published work. Excess 210Pb inventories in the shelf sediments show accumulations that are nearly in balance with the supply, even in areas of relict sands where it is believed that no net accumulation of sediment presently occurs. The 210Pb distributions in shelf and slope water indicate that the two-way fluid exchange at the shelf-slope front and the net transport in the alongshore flow make comparatively small contributions to the shelf 210Pb budget. The near balance between supply and decay of 210Pb on the shelf implies a limit to the particle export flux. It is concluded that the export of particulate organic carbon does not exceed 60 g m−2 y−1 (∼25% of primary production) and is probably lower. The hypothesis is advanced that fine particulate matter introduced to the continental shelf is detained in its transit of the shelf because of bioturbational trapping in the sediment due to benthic animals. Distributions of 210Pb in suspended particulate matter and in the fine fraction of shelf sediments suggest that the average fine particle must undergo several cycles of deposition-bioturbation-resuspension-redeposition and requires a number of decades for its transit and ultimate export from the shelf. Thus, only the most refractory organic matter is likely to be exported.

  7. 210Pb balance and implications for particle transport on the continental shelf, U.S. Middle Atlantic Bight

    USGS Publications Warehouse

    Bacon, M.P.; Belastock, Rebecca A.; Bothner, Michael H.

    1994-01-01

    Supply of 210Pb to the continental shelf off the northeastern United States is dominated by the deposition from the atmosphere, the rate of which is reliably known from previously published work. Excess 210Pb inventories in the shelf sediments show accumulations that are nearly in balance with the supply, even in areas of relict sands where it is believed that no net accumulation of sediment presently occurs. The 210Pb distributions in shelf and slope water indicate that the two-way fluid exchange at the shelf-slope front and the net transport in the alongshore flow make comparatively small contributions to the shelf 210Pb budget. The near balance between supply and decay of 210Pb on the shelf implies a limit to the particle export flux. It is concluded that the export of particulate organic carbon does not exceed 60 g m-2 y-1 (???25% of primary production) and is probably lower. The hypothesis is advanced that fine particulate matter introduced to the continental shelf is detained in its transit of the shelf because of bioturbational trapping in the sediment due to benthic animals. Distributions of 210Pb in suspended particulate matter and in the fine fraction of shelf sediments suggest that the average fine particle must undergo several cycles of deposition-bioturbation-resuspension-redeposition and requires a number of decades for its transit and ultimate export from the shelf. Thus, only the most refractory organic matter is likely to be exported. ?? 1994.

  8. Changes in the macrozoobenthos of the intertidal zone at Helgoland (German Bight, North Sea): a survey of 1984 repeated in 2002

    NASA Astrophysics Data System (ADS)

    Reichert, Katharina; Buchholz, Friedrich

    2006-09-01

    Changes in the presence and absence of invertebrates as well as in species conspicuousness were documented in a rocky intertidal community based on surveys in 1984 and 2002. In 2002 six vertically and/or morphologically different stations of an intertidal platform were sampled. Five of these six habitats had already been surveyed in 1984. Replicating precisely the method of the first assessment, presence/absence changes as well as changes in species conspicuousness of 83 invertebrate species were documented, indicating that this intertidal community changed considerably during the 18-year interval. Compared with the study in 1984, 27 species newly appeared, whereas 32 species disappeared. Furthermore, 16 species increased in conspicuousness, whereas eight invertebrates decreased. The total number of species in 2002 was 154 versus 158 in 1984. Although algal species were not recorded as thoroughly as invertebrates, a massive decline in cover of Halidrys siliquosa was noted. Conversely, two invasive algal species became established after 1984, Sargassum muticum (since 1988), a cosmopolitan fucoid alga that prefers shallow subtidal areas for colonization, and Mastocarpus stellatus (introduction in the 1980s) that particularly colonized areas in the mid intertidal. In 1984 the mid intertidal zone was dominated by the brown alga Fucus serratus, whereas in 2002 the blue mussel Mytilus edulis and the periwinkle Littorina littorea were the most conspicuous organisms. Annual mean sea surface temperature (BAH measurements) warmed by 1.1°C over the past four decades. Range-related community shifts, introductions of non-indigenous species and the input of pollutants, are considered to explain long-term ecological changes in the invertebrate community at Helgoland.

  9. California Basin Study (CaBS): Circulation and particle fluxes in the California bight: Six month progress report, May 15, 1989--November 14, 1989

    SciTech Connect

    Hickey, B.

    1989-01-01

    The following gives a brief summary of grant activities during the first six months of the new grant. During this period we have continued to edit and process data collected from the ten CTD/transmission/oxygen surveys. In addition, we continue to process George Jackson's cruise samples (at no cost to Jackson). The first three cruises have been completed. The next three should be completed within the six-month period. We have been experiencing computer difficulties: the PRIME computer is no longer supported by the School of Oceanography and we will ultimately be required to change processing systems. The Department of Energy, California Basin Study Program continued with the CaBS-10, Leg 2 cruise onboard the R/V New Horizon which departed from San Pedro, California on October 1, 1988 and returned to San Diego, California on October 7, 1988. The cruise was multi-disciplinary in nature involving physical, chemical, and biological measurements. The weather and seas were good, so that no time was lost due to weather or sea state. Captain Muench and the crew of the New Horizon were all very cooperative and helpful. Restrictions imposed by the Pacific Missile Range, and by the positioning of all the current meter moorings on the eastern side of the basins altered the scheduling and limited the number of our CTD stations in the western basins somewhat. However, we met all of our projected goals of sampling and of mooring recovery and deployment, and occupied 102 CTD stations, more than on any previous CaBS cruise.

  10. DISTRIBUTION OF SQUID PARALARVAE, LOLIGO OPALESCENS (CEPHALOPODA: MYOPSIDA), IN THE SOUTHERN CALIFORNIA BIGHT IN THE THREE YEARS FOLLOWING THE 1997 EL NINO. (R825381)

    EPA Science Inventory

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

  11. Experimental trials on the feasibility of offshore seed production of the mussel Mytilus edulis in the German Bight: installation, technical requirements and environmental conditions

    NASA Astrophysics Data System (ADS)

    Buck, Bela Hieronymus

    2007-06-01

    This study summarizes the activities and findings during a 2 year investigation on the grow-out of blue mussels ( Mytilus edulis) and the technical requirements to withstand harsh weather conditions at an offshore location. The experimental sites were two different test areas, each 5 ha in size, 12-15 m in depth, in the vicinity of the offshore lighthouse “Roter Sand” located 15-17 nautical miles northwest of the city of Bremerhaven (Germany). Two versions of submerged longline systems were deployed: a conventional polypropylene longline in 2002 as well as a steel hawser longline in 2003, both featuring different versions of buoyancy modes. The spat collectors and grow-out ropes were suspended perpendicular from the horizontal longline for several months beginning in March of each respective year. The test sites were visited and sampled on a monthly basis using research vessels. Larval abundances in the surrounding water column reached numbers of up to 1,467 individuals m-3. Post-larval settlement success varied through the entire experimental period, ranging from 29 to 796 individuals of spat per meter of collector. Settled mussels reached a shell length of up to 28 mm 6 months after settlement. Based on the growth rates observed for the seed, it is projected that mussels would reach market size (50 mm) in 12-15 months post settlement, and at the observed densities, each meter of collector rope could yield 10.9 kg of harvestable mussels. The polypropylene line resisted storm conditions with wind waves of up to 6.4 m and current velocities of 1.52 m s-1 and was retrieved in autumn of 2002. In contrast, the steel hawser-based line did not withstand the harsh weather conditions. The steel-based line consisted of six twisted strands that were untwisted by the strong currents and turbulences and consequently the individual strands were torn. Additionally, the line was accidentally cut by a yacht in July 2003. The biological study revealed that the tested location near “Roter Sand” has the potential to become an offshore seed production site as well as being exploitable as a grow-out site for mussel production to market size. In light of the technical results, recommendations for mussel culture strategies using a polypropylene longline system are given.

  12. Biological processes in the water column of the South Atlantic Bight: Zooplankton responses: A progress report, June 1986 to June 1987

    SciTech Connect

    Paffenhoefer, G.A.

    1986-12-19

    During April of 1984 and 1985 we studied the effects of wind forcing on water flow on the inner and middle shelf off Georgia and South Carolina. We present in this Progress Report selected data from our SPREX cruise (Spring Runoff Experiment) in April 1985 and compare the date with results from our Pre-SPREX cruise in April 1984. River runoff in April 1985 was about 50% lower than the previous average. The overall water flow at midshelf off Charleston was alongshore at the surface and onshore near bottom. The water column was well mixed and started to show signs of stratification by the end of April 1985. The water flow data indicate that nearshore zooplankton would hardly be displaced towards offshore, whereas offshore zooplankton would be transported towards shore. A comparison of results from April 1984 with those from April 1985 shows major differences: Fairly high runoff and pronounced displacement of nearshore water towards offshore with northeastward wind stress resulted in strong offshore displacement of estuarine zooplankton in surface waters (April 1984). Low runoff and weak alongshore displacement of surface water with weak windstress resulted in no offshore displacement of estuarine zooplankton which were at abnormally low concentrations in their habitat (April 1985).

  13. High frequency sampling of the 1984 spring bloom within the mid-Atlantic Bight: Synoptic shipboard, aircraft, and in situ perspectives of the SEEP-I experiment

    NASA Technical Reports Server (NTRS)

    Walsh, J. J.; Wirick, C. D.; Pietrafesa, L. J.; Whitledge, T. E.; Hoge, F. E.; Swift, R. N.

    1986-01-01

    Moorings of current meters, thermistors, transmissometers, and fluorometers on the mid-Atlantic shelf, south of Long Island, suggest a cumulative seaward export of perhaps 0.35 g C/sq m/day between the 80 and 120 m isobaths during February-April 1984. Such a horizontal loss of algal carbon over the lower third of the water column would be 23 to 78% of the March-April 1984 primary production. This physical carbon loss is similar to daily grazing losses from zooplankton of 32-40% of the algal fixation of carbon. Metabolic demands of the benthos could be met by just the estimated fecal pellet flux, without direct consumption of algal carbon, while bacterioplankton needs could be served by excretory release of dissolved organic matter during photosynthesis. Sediment traps tethered 10 m off the bottom at the 120 m isobath and 50 m above the 500 m isobath caught as much as 0.16 to 0.26 g C /sq m/day during March-April 1984, in reasonable agreement with the flux estimated from the other moored instruments.

  14. High-frequency sampling of the 1984 spring bloom within the Mid-Atlantic Bight: Synoptic shipboard, aircraft, and in situ perspectives of the SEEP—I experiment

    NASA Astrophysics Data System (ADS)

    Walsh, John J.; Wirick, Creighton D.; Pietrafesa, Leonard J.; Whitledge, Terry E.; Hoge, Frank E.; Swift, Robert N.

    1988-05-01

    Moorings of current meters, thermistors, transmissometers, and fluorometers on the Mid-Atlantic shelf, south of Long Island, suggest a seaward export of perhaps 0.20 mg Chl m -3 day -1 at depths of 75-81 m, between the 80- and 120-m isobaths during February-April 1984. Using a C/Chl ratio of 45/1, such a horizontal loss of algal carbon over the lower third of the water column would be 19-67% of the March-April 1984 primary production within the overlying euphotic zone. This possible physical carbon loss is similar to daily grazing losses to zooplankton of 32-40% of the algal fixation of carbon. Metabolic demands of the benthos could be met by just the estimated fecal pellet flux, without direct consumption of the remaining algal carbon. Similarly bacterioplankton metabolism could be fueled by excretory release of dissolved organic matter during photosynthesis, rather than by consumption of particulate carbon. Sediment traps tethered 10 and 70 m off the bottom at the 120-m isobath caught as much as 0.10-0.16 g C m -2 during March-April 1984. This presumed vertical flux is about one-third to one-half of the horizontal flux of 0.30 g C m -2 day -1 estimated over the lower 33 m of the water column at the 100-m isobath. These estimates suggest that ˜50% of the carbon export at the shelf-break might be derived from the adjacent overlying water column, with the remainder from lateral injections of near-bottom particles originating on the inner shelf.

  15. Dredging Operations Technical Support Program. Evaluation of the 1980 Capping Operations at the Experimental Mud Dump Site, New York Bight Apex.

    DTIC Science & Technology

    1983-10-01

    the complex interactions of these and other acts (NACe4, 1981; Figure 2) while describing the jurisdiction in Congress for their administration. Toe... interactions between sediment-associated contaminants and the marine biota, therefore, is essential. 22. Chemical studits at the Mud Dump have been...but was seen to be less than that occur- 4-. ring within the Lover Bay complex (Gravesend Bay, Brooklyn). Both the O’Brien and Gere (1979) study and

  16. Arsenic and mercury contamination of sediments of geothermal springs, mangrove lagoon and the Santispac bight, Bahía Concepción, Baja California peninsula.

    PubMed

    Leal-Acosta, María Luisa; Shumilin, Evgueni; Mirlean, Nicolai; Sapozhnikov, Dmitry; Gordeev, Vyacheslav

    2010-12-01

    In order to find out the environmental impact on the coastal zone, the composition of sediments of the intertidal geothermal hot spring zone and adjacent area of Playa Santispac in the pristine Bahía Concepción (Baja California peninsula) was studied. High concentrations of As (13-111 mg kg⁻¹) and Hg (0.55-25.2 mg kg⁻¹) were found in the sediments of the geothermal sources. Arsenic and Hg concentrations decrease rapidly in the adjacent small mangrove lagoon sediments and reach background levels (0.7-2.6 mg kg⁻¹ and 6-60 μg kg⁻¹ respectively) in the marine sediments collected in front of Playa Santispac.

  17. Thematic mapper research in the earth sciences: Small scale patches of suspended matter and phytoplankton in the Elbe River Estuary, German Bight and Tidal Flats

    NASA Technical Reports Server (NTRS)

    Grassl, H.; Doerffer, R.; Fischer, J.; Brockmann, C.; Stoessel, M.

    1987-01-01

    A Thematic Mapper (TM) field experiment was followed by a data analysis to determine TM capabilities for analysis of suspended matter and phytoplankton. Factor analysis showed that suspended matter concentration, atmospheric scattering, and sea surface temperature can be retrieved as independent factors which determine the variation in the TM data over water areas. Spectral channels in the near infrared open the possibility of determining the Angstrom exponent better than for the coastal zone color scanner. The suspended matter distribution may then be calculated by the absolute radiance of channel 2 or 3 or the ratio of both. There is no indication of whether separation of chlorophyll is possible. The distribution of suspended matter and sea surface temperature can be observed with the expected fine structure. A good correlation between water depth and suspended matter distribution as found from ship data can now be analyzed for an entire area by the synoptic view of the TM scenes.

  18. Whole-body concentrations of elements in three fish species from offshore oil platforms and natural areas in the Southern California Bight, USA

    USGS Publications Warehouse

    Love, Milton S.; Saiki, Michael K.; May, Thomas W.; Yee, Julie L.

    2013-01-01

    elements. Forty-two elements were excluded from statistical comparisons as they (1) consisted of major cations that were unlikely to accumulate to potentially toxic concentrations; (2) were not detected by the analytical procedures; or (3) were detected at concentrations too low to yield reliable quantitative measurements. The remaining 21 elements consisted of aluminum, arsenic, barium, cadmium, chromium, cobalt, copper, gallium, iron, lead, lithium, manganese, mercury, nickel, rubidium, selenium, strontium, tin, titanium, vanadium, and zinc. Statistical comparisons of these elements indicated that none consistently exhibited higher concentrations at oil platforms than at natural areas. However, the concentrations of copper, selenium, titanium, and vanadium in Pacific sanddab were unusual because small individuals exhibited either no differences between oil platforms and natural areas or significantly lower concentrations at oil platforms than at natural areas, whereas large individuals exhibited significantly higher concentrations at oil platforms than at natural areas.

  19. Biological processes in the water column of the South Atlantic Bight. Volume 1. Published manuscripts. Progress report, June 1982-June 1985

    SciTech Connect

    Paffenhofer, G.A.; Yoder, J.A.

    1984-12-14

    Effects of the Gulf Stream on the outer southeastern US continental shelf were determined. The relationships of phytoplankton productivity and related processes to the oceanography of the inner shelf were investigated. Upwelling studies on the northeastern Florida shelf are described, and feeding and excretory rates of juvenile and adult zooplankton characteristic of advanced and matured upwellings on the southeastern continental shelf are reported. 6 figures. (ACR)

  20. The effects of preservation methods, dyes and acidification on the isotopic values (δ15N and δ13C) of two zooplankton species from the KwaZulu-Natal Bight, South Africa.

    PubMed

    de Lecea, Ander M; Cooper, Rachel; Omarjee, Aadila; Smit, Albertus J

    2011-07-15

    Stable isotope measurements are an important tool for ecosystem trophic linkage studies. Ideally, fresh samples should be used for isotopic analysis, but in many cases organisms must be preserved and analysed later. In some cases dyes must be used to help distinguish organisms from detritus. Since preservatives and dyes are carbon-based, their addition could influence isotopic readings. This study aims to improve understanding of the effects of sample storage method, dye addition and acidification on the δ(15)N and δ(13)C values of zooplankton (Euphasia frigida and Undinula vulgaris). Zooplankton was collected and preserved by freezing, or by the addition of 5% formalin, 70% ethanol, or 5% formalin with added Phloxine B or Rose Bengal, and stored for 1 month before processing. Samples in 5% formalin and 70% ethanol were also kept and processed after 3 and 9 months to study changes over time. Formalin caused the largest enrichment for δ(13)C and a slight enrichment for δ(15)N, while ethanol produced a slight depletion for δ(13)C, and different effects on δ(15)N depending on the species. In formalin, dyes depleted the δ(13)C values, but had variable effects on δ(15)N, relative to formalin alone. Acidification had no significant effect on δ(15)N or δ(13)C for either species. Long-term storage showed that the effects of the preservatives were species-dependent. Although the effects on δ(15)N varied, a relative enrichment in (13)C of samples occurred with time. This can have important consequences for the understanding of the organic flow within a food web and for trophic studies. .

  1. The Roles of Advection and In Situ Growth in Determining the Dynamics of Continental Shelf Zooplankton: High Frequency Measurements of Zooplankton Biomass Coupled with Measurements of Secondary Productivity in the Middle Atlantic Bight

    SciTech Connect

    Smith, Sharon L.

    1999-03-26

    Evaluation of the role of continental margins in planetary carbon cycles can be approached in various ways, with the extremes being knowledge generated either by large-scale studies of a few basic characteristics of the carbon cycle of shelves worldwide (comparative approach) or by temporally intensive studies of a few sites selected to typify contrasting processes. Mechanisms of cross-shelf transfer, for example, are presently of great interest and within the US there are at least four differing continental shelf environments in which cross-shelf processes are driven by storms (southern Bering Sea, northeastern US), by jets and eddies (northern California coast), by freshwater runoff (Bering Sea, Gulf of Mexico), and by frontal meanders and filaments of the Gulf Stream (southeastern US). Because the type and magnitude of the physical forcing, and its variability on an annual scale, are fundamental to the response of the carbon cycle, investigation of each of these shelves would offer insight useful to predictive global understanding of the carbon cycle on continental shelves.

  2. Global Ocean Tides. Part II. The Semidiurnal Principal Lunar Tide (M2), Atlas of Tidal Charts and Maps.

    DTIC Science & Technology

    1979-12-01

    tide data from Gill and Porter (1978, from deep-sea stations in the New York Bight), Wyrtki (1978, from island stations in the Pacific Ocean), Zetler...Bight by Gill and Porter (1979) verified the globally modeled, incredibly sharp tide decay (Figures a and b) across the continental shelf of less than...Part I (Schwiderski, 1978a) and the new slightly improved Tables 8M or 8N in Appendix A, which include the Gill and Porter (1978) data in interpolated

  3. Collected Reprints-1975. Volume I.

    DTIC Science & Technology

    1977-02-01

    Stubblefield. Morphologic Evolution and Sand Transport in the Mew York Bight. Mid-Atlantic Shel f/New York Bight ASLO Symposium , 65 -66. 950 SEA -A I...abundance and the b iolo~’i ~‘al requirements of the f ishand wild l ife resources . 16 U . S.C. 742 1(a) (4) authorizes NOAA to take such steps as may b...l ~~~~~ -~~~~~~~~ creep, resulting in an apparent instrumental dr ift in ..~. .-~~ . - pressure of about 430 nib. This (Irift , rapid at t irst

  4. Radon as a tracer of biogenic gas equilibration and transport from methane-saturated sediments

    NASA Technical Reports Server (NTRS)

    Martens, Christopher S.; Chanton, Jeffrey P.

    1989-01-01

    Data on Rn-222 activity in methane-rich gas bubbles from anoxic coastal sediments of Cape Lookout Bight, North Carolina, were used to determine gas equilibration with pore waters and the rates of ebullitive stripping and transport of gases to overlying waters and the atmosphere. Results showed that, during summer months, the bubble ebullition process strips and transports 1.9-4.8 percent/day of the standing crop of radon (and, by inference, other gases equilibrated with gas bubbles) in surface sediments of Cape Lookout Bight to the troposphere. Thus, the ebullitive mode of gas transport represents an effective mechanism for delivering reduced biogenic gases directly to the atmosphere.

  5. An interdisciplinary study of the estuarine and coastal oceanography of Block Island Sound and adjacent New York coastal waters

    NASA Technical Reports Server (NTRS)

    Yost, E. F. (Principal Investigator); Hollman, R.; Alexander, J.; Nuzzi, R.

    1974-01-01

    The author has identified the following significant results. Photo-optical additive color quantitative measurements were made of ERTS-1 reprocessed positives of New York Bight and Block Island Sound. Regression of these data on almost simultaneous ship sample data of water's physical, chemical, biological, and optical properties showed that ERTS bands 5 and 6 can be used to predict the absolute value of the total number of particles and bands 4 and 5 to predict the relative extinction coefficient in New York Bight. Water masses and mixing patterns in Block Island Sound heretofore considered transient were found to be persistent phenomena requiring revision of existing mathematical and hydraulic models.

  6. Wave Processes in Arctic Seas, Observed from TerraSAR-X

    DTIC Science & Technology

    2015-09-30

    of high resolution sea state forecast models in the German Bight, The International Archives of the Photogrammetry , Remote Sensing and Spatial...classification based on Terrasar-X imagery, The International Archives of the Photogrammetry , Remote Sensing and Spatial Information Sciences, Volume XL-7/W3

  7. RELATIONSHIPS BETWEEN SUMMER CONCENTRATIONS OF TOTAL NITROGEN AND CHLOROPHYLL A IN TEN COASTAL SYSTEMS IN THE EASTERN UNITED STATES

    EPA Science Inventory

    We have examined relationships between summer (JuneAugust) average concentrations of total nitrogen (TN) and chlorophyll a (chl a) concentrations in the near-shore Mid-Atlantic Bight and nine bays and estuaries in the eastern United States: Boston Harbor/Massachusetts Bay, Long I...

  8. Ecological Condition of Coastal Ocean Waters along the U.S. Western Continental Shelf: 2003

    EPA Science Inventory

    The western National Coastal Assessment program of EPA, in conjunction with the NOAA National Ocean Service, west coast states (WA, OR, and CA), and the Southern California Coastal Water Research Project Bight ’03 program, assessed the ecological condition of soft sediment habita...

  9. 40 CFR 125.57 - Law governing issuance of a section 301(h) modified permit.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... of a pollutant into the New York Bight Apex consisting of the ocean waters of the Atlantic Ocean... December 31, 1982, had a contractual arrangement to use a portion of the capacity of an ocean outfall... permit pursuant to subsection (h) of section 301 of the Federal Water Pollution Control Act...

  10. 50 CFR 635.2 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... western north Atlantic Ocean, including the Gulf of Mexico and the Caribbean Sea. Mid-Atlantic Bight means...)(4) or (c)(5). Atlantic HMS means Atlantic tunas, billfish, sharks, and swordfish. Atlantic Ocean, as used in this part, includes the North and South Atlantic Oceans, the Gulf of Mexico, and the...

  11. IDENTIFICATION OF SPECIES-ENVIRONMENT RELATIONSHIPS IN THE HUDSON-RARITAN ESTUARY AND RELATED SUB-BASINS

    EPA Science Inventory

    The US EP A's Regional Environmental Monitoring and Assessment Program (REMAP) conducted a study in 1993/94 to assess the effects of sediment contamination in the Hudson- Raritan area (Upper New York, Raritan Bay, Jamaica Bay, western Long Island Sound and the Bight Apex). This s...

  12. Extreme flood impact on estuarine and coastal biogeochemistry: the 2013 Elbe flood

    NASA Astrophysics Data System (ADS)

    Voynova, Yoana G.; Brix, Holger; Petersen, Wilhelm; Weigelt-Krenz, Sieglinde; Scharfe, Mirco

    2017-02-01

    Within the context of the predicted and observed increase in droughts and floods with climate change, large summer floods are likely to become more frequent. These extreme events can alter typical biogeochemical patterns in coastal systems. The extreme Elbe River flood in June 2013 not only caused major damages in several European countries but also generated large-scale biogeochemical changes in the Elbe estuary and the adjacent German Bight. The high-frequency monitoring network within the Coastal Observing System for Northern and Arctic Seas (COSYNA) captured the flood influence on the German Bight. Data from a FerryBox station in the Elbe estuary (Cuxhaven) and from a FerryBox platform aboard the M/V Funny Girl ferry (traveling between Büsum and Helgoland) documented the salinity changes in the German Bight, which persisted for about 2 months after the peak discharge. The Elbe flood generated a large influx of nutrients and dissolved and particulate organic carbon on the coast. These conditions subsequently led to the onset of a phytoplankton bloom, observed by dissolved oxygen supersaturation, and higher than usual pH in surface coastal waters. The prolonged stratification also led to widespread bottom water dissolved oxygen depletion, unusual for the southeastern German Bight in the summer.

  13. 77 FR 5879 - Endangered and Threatened Wildlife and Plants; Threatened and Endangered Status for Distinct...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-06

    ...We, NMFS, are issuing a final determination to list the Gulf of Maine (GOM) Distinct Population Segment (DPS) of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) as a threatened species under the Endangered Species Act (ESA), and the New York Bight (NYB) and Chesapeake Bay (CB) DPSs of Atlantic sturgeon as endangered species under the ESA. We have proposed protective regulations for the GOM......

  14. Marine Bioluminescence: Mechanisms and Evaluation

    DTIC Science & Technology

    1998-09-30

    study of bioluminescence in the S. California Bight using moored detectors, (3) continue study of luminescence in gelatinous zooplankton and marine snow...preparation were the principal efforts in the work on gelatinous zooplankton and marine snow. (4) Cytoskeletal investigations of Pyrocystis...potential adaptive significance of the wavelengths of light produced by gelatinous zooplankton . Bioluminescence spectra were measured from 100

  15. 49 CFR 571.225 - Standard No. 225; Child restraint anchorage systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... van-type vehicles, vehicles manufactured to be sold exclusively to the U.S. Postal Service, shuttle... (as that term is defined at § 571.3) that is rearward of the front seats(s). Seat bight means the area... Static Force Application Device 2 shown in Figures 17 and 18 of this standard. Shuttle bus means a...

  16. 49 CFR 571.225 - Standard No. 225; Child restraint anchorage systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... van-type vehicles, vehicles manufactured to be sold exclusively to the U.S. Postal Service, shuttle... (as that term is defined at § 571.3) that is rearward of the front seats(s). Seat bight means the area... Static Force Application Device 2 shown in Figures 17 and 18 of this standard. Shuttle bus means a...

  17. 49 CFR 571.225 - Standard No. 225; Child restraint anchorage systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... van-type vehicles, vehicles manufactured to be sold exclusively to the U.S. Postal Service, shuttle... (as that term is defined at § 571.3) that is rearward of the front seats(s). Seat bight means the area... Static Force Application Device 2 shown in Figures 17 and 18 of this standard. Shuttle bus means a...

  18. 49 CFR 571.225 - Standard No. 225; Child restraint anchorage systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... van-type vehicles, vehicles manufactured to be sold exclusively to the U.S. Postal Service, shuttle... (as that term is defined at § 571.3) that is rearward of the front seats(s). Seat bight means the area... Static Force Application Device 2 shown in Figures 17 and 18 of this standard. Shuttle bus means a...

  19. Monitoring ocean dumping with ERTS-1 data

    NASA Technical Reports Server (NTRS)

    Wezernak, C. T.; Roller, N.

    1973-01-01

    The results of an analysis of ERTS-1 data for the New York Bight collected on 16 August 1972 are described. Results are presented which show acid-iron wastes, sewage sludge, suspended solids, and major water mass boundary features in the study area. The potential of satellite remote sensing for monitoring large scale events such as ocean dumping is discussed.

  20. A GIS approach to model sediment reduction susceptibility of mixed sand and gravel beaches.

    PubMed

    Eikaas, Hans S; Hemmingsen, Maree A

    2006-06-01

    The morphological form of mixed sand and gravel beaches is distinct, and the process/response system and complex dynamics of these beaches are not well understood. Process response models developed for pure sand or gravel beaches cannot be directly applied to these beaches. The Canterbury Bight coastline is apparently abundantly supplied with sediments from large rivers and coastal alluvial cliffs, but a large part of this coastline is experiencing long-term erosion. Sediment budget models provide little evidence to suggest sediments are stored within this system. Current sediment budget models inadequately quantify and account for the processes responsible for the patterns of erosion and accretion of this coastline. We outline a new method to extrapolate from laboratory experiments to the field using a geographical information system approach to model sediment reduction susceptibility for the Canterbury Bight. Sediment samples from ten representative sites were tumbled in a concrete mixer for an equivalent distance of 40 km. From the textural mixture and weight loss over 40 km tumbling, we applied regression techniques to generate a predictive equation for Sediment Reduction Susceptibility (SRS). We used Inverse Distance Weighting (IDW) to extrapolate the results from fifty-five sites with data on textural sediment composition to field locations with no data along the Canterbury Bight, creating a continuous sediment reductions susceptibility surface. Isolines of regular SRS intervals were then derived from the continuous surface to create a contour map of sediment reductions susceptibility for the Canterbury Bight. Results highlighted the variability in SRS along this coastline.

  1. MIZEX, A Program for Mesoscale Air-Ice-Ocean Interaction Experiments in Arctic Marginal Ice Zones. VI. MIZEX-WEST,

    DTIC Science & Technology

    1985-05-01

    tamed. SUMMARY The winter 1983 temperature and salinity data S % gmO -t 25 .... 26 from the Bering Sea MIZ provided the most de- Toc -2 .. tailed...are defined as fol- lows: our data: o. Okubo’s data: *-North Sea; A-Cape Kennedy; + - Banana River; x -Manokin River; *-New York Bight; [-South- ern

  2. Observation-Based Dissipation and Input Terms for Spectral Wave Models, with End-User Testing

    DTIC Science & Technology

    2014-09-30

    scale influence of the Great barrier reef matrix on wave attenuation, Coral Reefs [published, refereed] Ghantous, M., and A.V. Babanin, 2014: One...quantitative calibration was done by means of altimeter observations of swell in the Great Australian Bight (Young et al., 2013) and validated through the

  3. Temporal and spatial variation in habitat characteristics of Tilefish (Lopholatilus Chamaeleonticeps) off the east coast of Florida

    USGS Publications Warehouse

    Able, Kenneth W.; Grimes, Churchill B.; Jones, Robert; Twichell, David C.

    1993-01-01

    The tilefish, Lopholatilus chamaeleonticeps, constructs burrows in carbonate sediments off the central east coast of Florida at similar temperatures (8.6-15.4°C) and in similar sediment textures (high proportion of silts and clays) to conspecifics in the Mid-Atlantic Bight. The depths at which we observed tile fish off Florida (150-290 m), based on submersible observations and sidescan sonar operations during 1983 and 1984, were similar to those recorded in 1975-1977 (137-266 m) before the inception of the directed fishery. Both are similar to the range observed in the Mid-Atlantic Bight although tilefish there can be found at shallower and slightly deeper depths (80-305 m). The largest burrows off Florida (1.5-m diameter) were smaller than those observed in the Mid-Atlantic Bight (up to 5 m). The behavior of tile fish around the burrow and the invertebrates and fishes co-inhabiting the burrows off Florida are nearly identical to those in the Mid-Atlantic Bight. Despite the relatively narrow annual temperature range observed off Florida, abrupt changes in temperatures (+6°C) occurred over a 48-h period based on thermograph records. Our observations, and those of others from several areas along the U.S. east coast, suggest that this species probably constructs burrows throughout its geographic range, and that temperature and sediment composition largely determine its distribution. Exclusion experiments off Florida, along with prior removal experiments in the Mid-Atlantic Bight, indicate that tilefish construct and maintain the burrows.

  4. Variability of the Southern California wave climate and implications for sediment transport

    USGS Publications Warehouse

    Xu, J. P.; Noble, M.A.

    2009-01-01

    We analyzed wave and wind data from 18 buoys in the Southern California Bight to characterize the spatial and temporal variability of the regional wave climate. Point Conception shelters most of the Bight from being directly impacted by North Pacific weather. The wave height inside the sheltered zone and to the east of the Channel Islands is less than half the wave height in the open ocean to the west. Within the sheltered Bight, storm waves (by proxy of being greater than the 95th percentile wave height for more than 6 hours) are mainly from the west, but long period swells (Tp >15 seconds) are mainly from the south-southwest. There are on average two to four storms during each winter month (November-March) and fewer than two storms per month for the rest of the year. The Channel Islands selectively block the westerly swells and make the wave climate in the Santa Barbara Channel different from the rest of the sheltered Bight. A statistically significant wave-height minimum exists in the area offshore Dana Point and Oceanside. The multiyear (2-23 years) wave-data records from all 18 buoys show negligible temporal trend, positive or negative. Like the wave climate, the long-term probability of sediment transport on the continental shelves of the Bight displays large difference between the sheltered and open-ocean (near Point Conception) sites. The return period of incipient sediment motion on the sheltered shelf breaks (one to five months) is at least two orders of magnitude longer than that on the Point Conception shelf break (0.6 day). Similar to the spatial distribution of wave heights, there is a systematic return-period maximum on the shelf off Dana Point and Oceanside. ?? 2009 The Geological Society of America.

  5. Occurrence of contaminants of emerging concern along the California coast (2009-10) using passive sampling devices

    USGS Publications Warehouse

    Alvarez, David A.; Maruya, Keith A.; Dodder, Nathan G.; Lao, Wenjian; Furlong, Edward T.; Smalling, Kelly L.

    2014-01-01

    Three passive sampling devices (PSDs), polar organic chemical integrative samplers (POCIS), polyethylene devices (PEDs), and solid-phase microextraction (SPME) samplers were used to sample a diverse set of chemicals in the coastal waters of San Francisco Bay and the Southern California Bight. Seventy one chemicals (including fragrances, phosphate flame retardants, pharmaceuticals, PAHs, PCBs, PBDEs, and pesticides) were measured in at least 50% of the sites. The chemical profile from the San Francisco Bay sites was distinct from profiles from the sites in the Southern California Bight. This distinction was not due to a single compound or class, but by the relative abundances/concentrations of the chemicals. Comparing the PSDs to mussel (Mytilus spp.) tissues, a positive correlation exists for the 25 and 26 chemicals in common for the PEDs and SPME, respectively. Diphenhydramine was the only common chemical out of 40 analyzed in both POCIS and tissues detected at a common site.

  6. Impact of Mid-Atlantic sewage sludge probed

    NASA Astrophysics Data System (ADS)

    Blue, Charles

    1992-01-01

    Every year since 1986, 8 million tons of raw sewage has been dumped into the ocean at the Mid-Atlantic Bight, an area 100 miles off the coast of New York and New Jersey. Originally, this location was thought to be a safe dump site because of its considerable depth and strong ocean currents, which would prevent sewage from accumulating on the ocean floor. Recently, several scientists tested that assumption and found evidence for significant amounts of sewage accumulation at the dump site.Scientific studies of the dump site, coordinated by NOAA's National Undersea Research Program, will be presented at the 1992 AGU Ocean Science Meeting in New Orleans, January 27-31. The studies reveal the extent of sewage sludge accumulation at the Mid-Atlantic Bight and determine the environmental impact that significant accumulations of this material has on the ocean environment.

  7. Surficial bioturbation and rapid benthic remineralization in the Cape Hatteras shelf/slope region. Final report

    SciTech Connect

    Robert C. Aller; Josephine Y. Aller; C. Lee; J. Kirk Cochran

    1999-03-17

    This is a final report for the DOE of grant DE-FG02-92ER61464 ''Surficial bioturbation and rapid benthic remineralization in the Cape Hatteras shelf slope region''. Over the past 6 years we have participated in a multidisciplinary field study called the Ocean margins Program (OMP) to examine the importance of continental margins in the global carbon cycle. Specifically, we have focused on the southern portion of the Mid-Atlantic Bight between Cape Hatteras and Chesapeake Bay where a large flux of freshwater and organic carbon enters the North Atlantic Ocean. Additionally, during the first stage of this project, we developed the use of CM-a distributions in sediments as a quantitative indicator of benthic C flux and remineralization rates. The primary objective of our research group has been to understand mechanisms and quantify biogeochemical processes in the seabed that affect cycling, flux, and storage of carbon on the ocean margin of the Mid-Atlantic Bight.

  8. Atlantic Coastal Experiment III: R/V KNORR cruise 68, 4-30 August 1977; FRV ALBATROSS IV cruise 77-07, 1-4, 16-31 August 1977. Data report, volume 1

    SciTech Connect

    Judkins, D.C.; von Bock, K.

    1983-03-01

    Data are reported from KNORR cruise 68, the major investigation of the third Atlantic Coastal Experiment (ACE), conducted during a period of pro-nounced water-column stratification. One hundred fifty-five stations, including 6 time-series sitings, were occupied within the shelf and shelf- break regimes of New York Bight. Measurements were made to assess water-mass characterization, nutrient cycling, carbon/nitrogen assimilation, bio-mass distribution and diel dynamics and benthic/water-column interfacial exchange. Data are also included from the cruise of ALBATROSS IV carried out contemporaneously with the KNORR investigations, in an area ranging from Nantucket Shoals to the upper reaches of the Gulf of Maine. 20 hydrographic stations were used to augment underway mapping in order to elucidate surface-layer chlorophyll and nutrient distributions occurring at an impor-tant boundary of the New York Bight.

  9. Ocean internal waves off the North American and African coasts from ERTS-1

    NASA Technical Reports Server (NTRS)

    Apel, J. R.; Charnell, R. L.

    1974-01-01

    Periodic features observed in the ocean portions of certain ERTS-1 images have been identified with reasonable certainty as surface manifestations of oceanic internal gravity waves. A series of images taken over the New York Bight, commencing with the 16 July 1972 overpass and continuing on into autumn of 1973, has shown the internal waves to be present when summer solar heating stratifies the water sufficiently well to support such oscillations. When fall and winter wind action mixes the shelf water down to the bottom, the waves no longer appear. In the Bight, the wavelengths range from approximately 400 to 1000 m, with the wave field being most sharply delineated near the edges of the continental shelf, at the mouth of the Hudson Canyon. They appear in packets consisting of several waves separated by 10-15 km, which propagate up on the shelf and disappear.

  10. Acoustic tracking of woodhead seabed drifters

    NASA Technical Reports Server (NTRS)

    Mayhue, R. J.; Lovelady, R. W.

    1977-01-01

    An investigation was conducted to determine the feasibility of tracking Woodhead seabed drifters that were instrumented with miniature acoustic transmitters having a range in water in excess of 1.0 n.mi. A trial cruise at the entrance of Delaware Bay, with the R.V. Annandale as the sonar-tracking vessel, verified acoustic communications and positioning of the bottom drifters. A demonstration cruise with the R.V. Annandale was also performed in the New York Bight to attempt to collect information on bottom water movement near the sewage-sluge dump site. Results from the tracking mission in the New York Bight suggested that bottom water currents were negligible near the dump site during the time interval from November 7-12, 1975, and that shipboard sonar tracking of acoustic Woodhead seabed drifters could provide useful Lagragian information on bottom water movement caused by tidal and other nonstorm effects.

  11. Engineers of the Southwest Pacific 1941-1945. Volume 8. Critique

    DTIC Science & Technology

    1950-01-01

    dock hard- as relay teams in conjunction with small craft or ware, and welding supplies were all too often not aerial cableways to quickly transfer...3,000 feet. These guns had to be disassembled and land offensive to victory was cut. The and hauled over sheer precipices by ropes . CHRONICILE Operation...bights at each end, were fastened to each pile. retreated to the north corner of the island. (Manila rope , 2 inches or 1Y2 inches, was sug- However

  12. Analysis of Observations from the Coastal Mixing and Optics Moored Array

    DTIC Science & Technology

    2016-06-07

    water column and meteorological measurements to estimate surface fluxes. Additionally we plan to do some simple modeling to aid in interpreting the...Intrusions of anomalously salty (and typically warm) water from the slope are often found over the continental shelf of the Middle Atlantic Bight and were...generation mechanism. The water temperature during CMO exhibited a large seasonal variation. Depth-averaged temperatures reached a maximum (14ºC) in mid

  13. West Coast Naval Training Range Demonstration of Glider-Based Passive Acoustic Monitoring

    DTIC Science & Technology

    2013-09-30

    frequency Acoustic Recording Package ( HARP ) described by Wiggins and Hildebrand (2007). Figure 1. The ZRay flying wing autonomous underwater...towed array from SPAWAR SSC Pacific. The Wave Glider included a HARP data logger connected to a wide-band hydrophone towed from the submerged wing...Both the ZRay and the Wave Glider were operated near an array of three bottom-mounted HARPs deployed in the southern California Bight as part of the

  14. Spatial Variability and Robust Interpolation of Seafloor Sediment Properties Using the SEABED Databases

    DTIC Science & Technology

    2007-01-01

    for spatial analysis by their location within sample regions: polygonal areas defined in ArcGIS chosen by geography , water depth, and data sufficiency... fractal dimension. 2 Figure 2. Location of usSEABED records within the mid-Atlantic Bight, color coded by mean grain size, and...best-fit von Kármán model with noise spike is overlain (dashed), with parameter values as indicated. The fractal dimension of the model is 1.5

  15. Interactions Among Behavioral Responses of Baleen Whales to Acoustic Stimuli, Oceanographic Features, and Prey Availability

    DTIC Science & Technology

    2014-09-30

    observed are feeding, traveling, resting, and socializing. Blue whales visit the southern California Bight in the summer months primarily to forage, and...ecological decisions made by individual whales when foraging, and how the broader oceanographic environment affects blue whales in southern California...including blue whales and thus is considered the most accurate way of determining feeding events in baleen whales from tag-derived records. Data from the

  16. Antarctic Atmospheric Infrasound.

    DTIC Science & Technology

    1986-11-01

    system. These are microbaroms, aurural infrasonic waves, mountain associated infrasound, Mount Erebus eruptive events, and signals related to large...array. Mount Erebus is an active volcano located only fifteen miles from the Windless Bight array. Frequent mini-eruptions from the lava lake at the...MAX, Velocity MIN & MAX, and Start & Stop. To produce a listing of all events that were caused by Mount Erebus on the tape: Choose the T array, and

  17. Use of the Ocean for Man’s Wastes. Proceedings of Symposium Held at Lewes, Delaware on 23-24 June 1981.

    DTIC Science & Technology

    1981-01-01

    organic matter. This has not been documented yet. There may also be a dissolution of calcium carbonate in the coastal zone as a consequence of this...the Southern California Bight from about 11 million people. Let me just cite another example. This is the case of the radioactive cesium ingestion by...origin may be distinguished by very small differ- ences in temperature, salinity, oxygen, silicate content, or in the concentration of other dissolved

  18. Marine ecoregion and Deepwater Horizon oil spill affect recruitment and population structure of a salt marsh snail

    USGS Publications Warehouse

    Pennings, Steven C.; Zengel, Scott; Oehrig, Jacob; Alber, Merryl; Bishop, T. Dale; Deis, Donald R.; Devlin, Donna; Hughes, A. Randall; Hutchens, John J.; Kiehn, Whitney M.; McFarlin, Caroline R.; Montague, Clay L.; Powers, Sean P.; Proffitt, C. Edward; Rutherford, Nicolle; Stagg, Camille L.; Walters, Keith

    2016-01-01

    Marine species with planktonic larvae often have high spatial and temporal variation in recruitment that leads to subsequent variation in the ecology of benthic adults. Using a combination of published and unpublished data, we compared the population structure of the salt marsh snail, Littoraria irrorata, between the South Atlantic Bight and the Gulf Coast of the United States to infer geographic differences in recruitment and to test the hypothesis that the Deepwater Horizon oil spill led to widespread recruitment failure of L. irrorata in Louisiana in 2010. Size-frequency distributions in both ecoregions were bimodal, with troughs in the distributions consistent with a transition from sub-adults to adults at ~13 mm in shell length as reported in the literature; however, adult snails reached larger sizes in the Gulf Coast. The ratio of sub-adults to adults was 1.5–2 times greater in the South Atlantic Bight than the Gulf Coast, consistent with higher recruitment rates in the South Atlantic Bight. Higher recruitment rates in the South Atlantic Bight could contribute to higher snail densities and reduced adult growth in this region. The ratio of sub-adults to adults in Louisiana was lower in 2011 than in previous years, and began to recover in 2012–2014, consistent with widespread recruitment failure in 2010, when large expanses of spilled oil were present in coastal waters. Our results reveal an important difference in the ecology of a key salt marsh invertebrate between the two ecoregions, and also suggest that the Deepwater Horizon oil spill may have caused widespread recruitment failure in this species and perhaps others with similar planktonic larval stages.

  19. Characterization and Modeling of the Philippine Archipelago Dynamics Using the ROMS 4DVAR Data Assimilation System

    DTIC Science & Technology

    2010-09-30

    2010a,b,c; Powell et al. 2008; Muccino et al., 2008; Di Lorenzo et al., 2007), ensemble prediction, adaptive sampling, circulation stability (Moore... Lorenzo (Southern California predictability) at Georgia 6 Institute of Oceanography, and J. Wilkin (Mid-Atlantic Bight variational data...grant number N00014­ 10-1-0322, http://www.myroms.org. REFERENCES Di Lorenzo , E., A.M. Moore, H. G. Arango, B. D. Cornuelle, A. J. Miller, B

  20. A Community Terrain-Following Ocean Modeling System (ROMS/TOMS)

    DTIC Science & Technology

    2009-01-01

    representer-based weak constraint 4DVar (Di Lorenzo et al., 2007; Muccino et al., 2008) driver (R4D-Var) and a weak constraint Physical Space Analysis...Institute of Oceanography, E. Di Lorenzo (Southern California predictability) at Georgia Institute of Oceanography, and J. Wilkin (Mid-Atlantic Bight...j.dynatmoce.2009.03.001. Courtier, P., 1997: Dual formulation of four-dimensional variational assimilation, Q.J.R. Meteorol. Soc., 123, 2449-2461. Di Lorenzo

  1. Bibliography on Tidal Hydraulics. Supplementary Material Compiled from June 1983 to June 1986. Tidal Flows in Rivers and Harbors. Supplement Number 10.

    DTIC Science & Technology

    1987-06-01

    the German Bight which look rather sim- entering the sheltered waters on the South ila r. The reference values of the corre- East Queensland coast...points in the investigated sea region, ment of Geology , University of South so as to examine the circulation mechanism Florida, Tampa. of the bay water...compilation of " Geology and Geotechnical Characteristics beach profiles (showing both the maximum of Sediments in East Bay Area, Mississippi and minimum

  2. Dredging Operations Technical Support Program. Effectiveness of Capping in Isolating Dutch Kills Sediment from Biota and the Overlying Water.

    DTIC Science & Technology

    1986-06-01

    Identify by block num ber) Marine pollution --Experiments (LC) Environmental engineering (LC) Contamination (Technology) (LC) Dredged material (WES...Harbor Sediments and Dredging Spoil," Marine Pollution Bulletin, Vol 12, No. 10 pp 351-353. Babinchak, J. A., Graikoski, J. T., Dudley, S., and...Vol 34, No. 1, pp 38-41. ___-___ 1977b. "Distribution of Fecal Coliforms in Bottom Sediments fromEl the New York Bight," Marine Pollution Bulletin, Vol

  3. The Secretary of the Navy/Chief of Naval Operations Chair in Oceanographic Sciences

    DTIC Science & Technology

    2014-09-30

    dynamics, turbulence, internal gravity waves, sediment transport, and harmful algal blooms , and 3) the physical, bio-optical, and biogeochemical...features and eddies; ship-based bio-optical data collected by the Plumes and Blooms Program (Dave Siegel, lead-PI; http://www.icess.ucsb.edu/PnB/PnB.html...analysis in the Southern California Bight from a numerical product, submitted to Journal of Geophysical Research. bloom west of the Island of Hawaii

  4. Atlantic Coastal Experiment VI: R/V KNORR cruise, 23 August--11 September 1980, data report

    SciTech Connect

    Behrens, W.; von Bock, K.

    1983-01-01

    An investigation of the influence of estuaries on the ecosystem of the Mid-Atlantic Bight was undertaken. Data were collected from excursions into the Hudson, Delaware and Chesapeake estuaries, three across-shelf and one along-shelf transects, and two time series stations. In all, 139 stations were occupied and 164 XBT soundings were taken. In addition to standard hydrographic measurements, nutrient , chlorophyll, particulate carbon and nitrogen, 14C, 15N, DNA, particle size, FTD, phytoplankton and zooplankton analyses were made.

  5. Diseases in North Sea fishes

    NASA Astrophysics Data System (ADS)

    Dethlefsen, V.

    1984-03-01

    Prior to the studies reviewed here, only lymphocystis and skeletal deformities of a variety of fish species and certain diseases of eel were known to occur in the German Bight (North Sea). From 1977 until now, 9 externally visible lesions on North Sea fishes were observed; in addition to those mentioned before, they comprise: fin rot, ulcerations, epidermal papilloma, hyperplasia, pseudobranchial tumour, eye diseases and gill swellings. With the exception of information on changes in frequencies of vertebral deformities of herring from the 1950's to the 1970's, there are no long-term data characterizing changes in frequencies of the diseases under study. For pseudobranchial tumours of cod and epidermal papilloma of dab, information is provided on occurrence and abundance. The distribution pattern of cod afflicted with pseudobranchial tumours is strongly influenced by the migratory behaviour of the fish. Epidermal papillomas of dab were more frequently found at stations within the inner German Bight than in neighbouring areas. The Bight is used for dumping of wastes from titaniumdioxide production. Further disease hot spots are areas off the Humber estuary and the British coast. Analysis of chromium in dab from the German Bight revealed elevated concentrations in epidermal tissues of specimens from the dumping area compared with that found in dab from neighbouring localities. Particulate iron was demonstrated to occur in mucous cells of dab from the dumping area. From increased levels of heavy metals with cancerogenic potential in sensitive target tissues and from increased prevalences of diseased fish in the dumping area it is concluded that these phenomena are possibly causally linked. In the vicinity of the Humber estuary high disease rates were encountered and areas with high prevalences of dab afflicted with epidermal papilloma extended over regions shown to be transport routes for persistent pollutants such as radioactive materials. It is therefore suggested

  6. A comparison of two finite element models of tidal hydrodynamics using a North Sea data set

    USGS Publications Warehouse

    Walters, R.A.; Werner, F.E.

    1989-01-01

    Using the region of the English Channel and the southern bight of the North Sea, we systematically compare the results of two independent finite element models of tidal hydrodynamics. The model intercomparison provides a means for increasing our understanding of the relevant physical processes in the region in question as well as a means for the evaluation of certain algorithmic procedures of the two models. ?? 1989.

  7. Wave-Current Interaction in Coastal Inlets and River Mouths

    DTIC Science & Technology

    2012-09-30

    from R/V Questuary over the sill in Raccoon Strait (San Francisco Bay) opposing a developing flood tide. Right panel: drifter deployment in San...Francisco Bight (camera is looking north-westward from under the Golden Gate). We conducted several experiments in Raccoon Strait located inside San...currents (bottom) as recorded by the WRD cluster indicated in red (left panel). RESULTS We conducted several short experiments in Raccoon

  8. Hydrodynamics of internal solitons and a comparison of SIR-A and SIR-B data with ocean measurements

    NASA Technical Reports Server (NTRS)

    Apel, J. R.; Gasparovic, R. F.; Thompson, D. R.

    1986-01-01

    Large internal solitary waves have been observed by Shuttle SIR-A and SIR-B at locations in the Andaman Sea and the New York Bight. Satellite imagery and oceanographic measurements are used in conjunction with hydrodynamic interaction and electromagnetic scattering models to estimate the expected SAR image intensity modulations associated with the internal waves. There is reasonable agreement between the predicted and observed internal wave signatures.

  9. Corrigendum to ;Stirring by deep cyclones and the evolution of Denmark strait overflow water observed at Line W; [Deep-Sea Res. I 109, 10-26

    NASA Astrophysics Data System (ADS)

    Andres, M.; Toole, J. M.; Torres, D. J.; Smethie, W. M.; Joyce, T. M.; Curry, R. G.

    2017-03-01

    The Line W program was a 10-year study (2004-2014) to investigate variability in the Deep Western Boundary Current (DWBC) and the nearby ocean interior south of New England. Line W stretches from the Middle Atlantic Bight continental slope southeastward towards Bermuda along a satellite altimeter track and is roughly orthogonal to the 2500-3500 m isobaths along the continental slope here (Fig. 1a).

  10. Infrared view of Bangkok, Thailand

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Bight of Bangkok and the city of Bangkok, Thailand are visible in this west looking view. The city, of almost four million people, long famous as a jewelry, silver and bronze ware trading center is also a major rice grower. Situated in a vast lowland ideal for rice agriculture, it is now a major export commodity. The vast network of canals are used for irrigation and drainage and the deforested hills of the Bilauktaung Range are seen nearby.

  11. Application of ERTS-1 data to the protection and management of New Jersey's coastal environment

    NASA Technical Reports Server (NTRS)

    Yunghans, R. S.; Feinberg, E. B.; Wobber, F. J. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Photomaps, using MSS bands 5 and 7, have been prepared delineating the coastal zone as described in the Coastal Area Facility Review Act before the State Legislature. An upper wetlands boundary overlay has been prepared at 1:500,000 scale. The movement and dispersion of wastes in the New York Bight area are being plotted with each orbit. The possible impact of these wastes on the New Jersey shoreline is being quantified.

  12. Airborne, In Situ and Laboratory Measurements of the Optical and Photochemical Properties of Surface Marine Waters

    DTIC Science & Technology

    2016-06-07

    Airborne, In Situ And Laboratory Measurements Of The Optical And Photochemical Properties Of Surface Marine Waters Neil V. Blough Department of...matter (CDOM) in marine and estuarine waters , 2) to determine the impact of CDOM on the aquatic light field and remotely-sensed optical signals, 3) to...October 1999 was performed to examine the optical and photochemical properties of waters in the Middle Atlantic Bight and in the Delaware and Chesapeake

  13. Behavioral Context of Blue and Fin Whale Calling for Density Estimation

    DTIC Science & Technology

    2014-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Behavioral context of blue and fin whale calling for...in which we will determine the context-appropriate call production rates for blue and fin whales in the Southern California Bight, with the end goal...of facilitating density estimation from passive acoustic data. OBJECTIVES Before a reliable estimate of blue and fin whale call production rates

  14. Sediment contamination and associates laboratory-measured bioaccumulation in New York/New Jersey waterways

    SciTech Connect

    Rosman, L.B.; Barrows, E.S.

    1995-12-31

    Sediments from 10 New York/New Jersey waterways within the Hudson-Raritan Estuary and Long Island Sound were collected to depths representative of dredging activity. Composited core sediments representing each waterway were analyzed for metals, PAHs, PCBs, and pesticides. To assess bioaccumulation, sand worms (Nereis virens) and blunt-nose clams (Macoma nasuta) were exposed for 28 days to sediment composites and to New York Bight sediment. Tissues were analyzed for the same constituents as the sediment samples. The results highlight the range and magnitude of sediment contamination in NY/NJ waterways. Concentrations of some metals in sediments, compared with NY Bight sediment, were at least 10 times higher. Total PAHs reached 30,000 {micro}g/kg (dry weight). The sum of DDT, DDD, and DDE, the dominant pesticides, exceeded 3,000{micro}g/kg (dry weight). Total PCBs approached 3,000 {micro}g/kg (dry weight). Tissues exposed to sediments from several waterways bioaccumulated organic compounds at concentrations 10 times greater than those exposed to New York Bight sediments. Metals were bioaccumulated to a lesser degree. The presence and extent of bioaccumulated contaminants, along with sediment chemistry and benthic toxicity, create a profile characterizing each waterway.

  15. Natural variability in hard-bottom communities and possible drivers assessed by a time-series study in the SW Baltic Sea: know the noise to detect the change

    NASA Astrophysics Data System (ADS)

    Wahl, M.; Hinrichsen, H.-H.; Lehmann, A.; Lenz, M.

    2013-07-01

    In order to detect shifts in community structure and function associated with global change, the natural background fluctuation in these traits must be known. In a 6 yr study we characterized the composition of young benthic communities at 7 sites along the 300 km coast of the Kiel and Lübeck bights in the German Baltic Sea and we quantified their interannual variability of taxonomic and functional composition. Along the salinity gradient from NW to SE, the relative abundance of primary producers decreased while that of heterotrophs increased. Along the same gradient, annual productivity tended to increase. Taxonomic and functional richness were higher in Kiel Bight as compared to Lübeck Bight. With increasing species richness functional group richness showed saturation indicating an increasing functional redundancy in species rich communities. While taxonomic fluctuations between years were substantial, functionality of the communities seem preserved in most cases. Environmental conditions potentially driving these fluctuations are winter temperatures and current regimes. We tentatively define a confidence range of natural variability in taxonomic and functional composition a departure from which might help identifying an ongoing regime shift driven by global change. In addition, we propose to use RELATE, a statistical procedure in the PRIMER (Plymouth Routines in Multivariate Ecological Research) package to distinguish directional shifts in time ("signal") from natural temporal fluctuations ("noise").

  16. Surface Sediment Geochemistry in and around the Hudson Shelf Valley Offshore of New York

    NASA Astrophysics Data System (ADS)

    Mecray, E. L.; ten Brink, M. B.; Butman, B.; Denny, J.; Murray, R. W.

    2001-05-01

    The Hudson Shelf Valley, an ancient submerged portion of the Hudson River, extends across the continental shelf offshore of New York and New Jersey. Between 1959 and 1987, the area near the head of the valley was used for disposal of approximately 1.20 x 108 m3 of dredged material and sewage sludge. The distribution of metal concentrations and sediment characteristics were used to investigate the transport and fate of the sediments and their associated contaminants. Surface (0-2cm) sediments collected at 440 stations throughout the New York Bight between 1993 and 1998 were used to establish the regional distribution of pollutant metals, grain size, organic carbon, and Clostridium perfringens spores. Sediments in the New York Bight are generally sandy, however fine-grained sediments are found in the axis of the Valley. Statistical methods identified common sources and chemical mobility within groups of anthropogenic and naturally-occurring elements. High metal concentrations, fine-grained sediments, and higher organic carbon concentrations co-occur in depo-centers within the Valley. Normalization of the metal concentrations to these factors shows higher metal concentrations on the fine-grained particles in sandy areas of the Bight, particularly along the southern shore of Long Island. These distributions have implications for evaluating the impact of the mass distribution for contaminated metals in different habitats and areas. Decreasing concentrations of pollutants with time are observed, reflecting reduced contaminant loading in the upper region of the Valley; however, concentrations are still above natural background levels.

  17. Seasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability

    PubMed Central

    de la Vega, Camille; Lebreton, Benoit; Siebert, Ursula; Guillou, Gael; Das, Krishna; Asmus, Ragnhild; Asmus, Harald

    2016-01-01

    The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight. PMID:27176227

  18. Burial, remineralization and utilization of organic matter at the seafloor under a strong western boundary current. Annual progress report, 1 May 1993--30 April 1994

    SciTech Connect

    Jahnke, R.A.

    1993-12-30

    The overall objectives of this project are to quantify the rates of organic carbon export from the southern mid-Atlantic Bight and to quantify the rates at which carbon is exchanged between the inorganic and organic pools within the bottom sediments. The strategy for achieving these goals is to quantify the rates of benthic exchange and burial of bioactive elements including oxidants (such as oxygen, nitrate, sulfate), micronutrient, and carbon system parameters on the continental shelf, slope and rise regions within and adjacent to the south portion of the mid-Atlantic Bight. This information, in conjunction with burial rates provided by others in this program, will be used to determine the locations and rates of export and oxidative loss of organic matter from the shelf. During this past funding period, three expeditions were completed to the study region, successfully conducting 6 in situ benthic flux chamber experiments. The results provide an initial assessment of the magnitude and location of organic matter export from the southern Middle Atlantic Bight shelf and of the importance of this region as a supplier of organic carbon to the North Atlantic Ocean Basin.

  19. Spatial distribution of PAHs and associated laboratory-measured bioaccumulation in New York/New Jersey waterways

    SciTech Connect

    Rosman, L.B.; Barrows, E.S.

    1995-12-31

    Sediment core samples from New York/New Jersey waterways within the Hudson-Raritan Estuary and Long Island Sound were collected to depths representative of dredging activity. Sediment was also collected from a reference site in the New York Bight as a comparison. Composited core sediments representing each waterway were analyzed for PAHs, sediment grain size, and total organic carbon. To assess bioaccumulation, sand worms (Nereis virens) and blunt-nose clams (Macoma nasuta) were exposed for 28 days to sediment composites and to New York Bight sediment. Tissues were analyzed for the same constituents as the sediment samples, as well as for lipid content. The results highlight the range and magnitude of PAH concentrations in sediments of NY/NJ waterways. Concentrations of total PAHs ranged from undetected to 30,000 {micro}g/kg (dry weight). Tissues exposed to sediments from several waterways bioaccumulated organic compounds at concentrations as much as 10 times greater than those exposed to New York Bight sediments. The presence and extent of bioaccumulated compounds, along with benthic toxicity data, create a profile characterizing each waterway.

  20. Seasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability.

    PubMed

    de la Vega, Camille; Lebreton, Benoit; Siebert, Ursula; Guillou, Gael; Das, Krishna; Asmus, Ragnhild; Asmus, Harald

    2016-01-01

    The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight.

  1. A review of the shelf-slope circulation along Australia’s southern shelves: Cape Leeuwin to Portland

    NASA Astrophysics Data System (ADS)

    Middleton, John F.; Bye, John A. T.

    2007-10-01

    A review is presented of the ocean circulation along Australia’s southern shelves and slope. Uniquely, the long, zonal shelf is subject to an equatorward Sverdrup transport that gives rise to the Flinders Current - a small sister to the world’s major Western Boundary Currents. The Flinders Current is strongest near the 600 m isobath where the current speeds can reach 20 cm/s and the bottom boundary layer is upwelling favourable. It is larger in the west but likely intermittent in both space and time due to possibly opposing winds, thermohaline circulation and mesoscale eddies. The Flinders Current may be important to deep upwelling within the ubiquitous canyons of the region. During winter, the Leeuwin Current and local winds act to drive eastward currents that average up to 20-30 cm/s. The currents associated with the intense coastal-trapped wave-field (6-12 day band) are of order 25-30 cm/s and can peak at 80-90 cm/s. Wintertime winds and cooling also lead to downwelling to depths of 200 m or more and the formation of dense coastal water within the Great Australian Bight and the South Australian Sea. Within the Great Australian Bight, the thermohaline circulation associated with this dense water is unknown, but may enhance the eastward shelf-edge, South Australian Current. The dense salty water formed within Spencer Gulf is known to cascade as a gravity current to depths of 200 m off Kangaroo Island. This dense water outflow and meanders in the shelf circulation also fix the locations of a sequence of quasi-permanent mesoscale eddies between the Eyre Peninsula and Portland. During summer, the average coastal winds reverse and surface heating leads to the formation of warm water in the western Great Australian Bight and the South Australian Sea. No significant exchange of shelf water and gulf water appears to occur due to the presence of a dense, nutrient-rich (sub-surface) pool that is upwelled off Kangaroo Island. The winds lead to weak average coastal

  2. Emerging pollutants in the North Sea in comparison to Lake Ontario, Canada, data.

    PubMed

    Andresen, Jens Arne; Muir, Derek; Ueno, Daisuke; Darling, Colin; Theobald, Norbert; Bester, Kai

    2007-06-01

    In the present study, the concentrations and fate of contaminants such as organophosphate flame retardants and plasticizers, musk compounds such as galaxolide (HHCB), tonalide (AHTN), musk ketone and musk xylene, the bactericide triclosan, as well as the metabolites HHCB-lactone and triclosan-methyl were compared in the aqueous phase of the German Bight (North Sea). The concentrations of these compounds were around 1 to 10 ng/L in nearshore areas, and the concentrations were lower in the more pristine areas. The highest concentrations were determined for tris-(2-chloro-isopropyl) phosphate in the North Sea with concentration exceeding 10 ng/L even for the offshore samples. The samples contained 1 to 20 ng/L chlorinated organophosphates, approximately 1 ng/L nonchlorinated organophosphates, and 0.3 to 3 ng/L fragrance compounds. Some samples from Lake Ontario (Canada) were analyzed in comparison. Per capita emissions were calculated for both regions. These emissions were compared and turned out to be very similar for the Canadian and German locations. For the North Sea, some observations concerning stability, dilution, and degradation, as well as sources of the respective substances, were performed. These data indicate that the chlorinated organophosphates and some musk fragrances exhibit half lives exceeding the residence times and thus can be considered to be persistent in this ecosystem. In the German Bight, the river Elbe is the dominating source for the more hydrophilic compounds, such as chlorinated organophosphate flame retardants, which are diluted only into the North Sea. However, for the more lipophilic compounds such as the musk fragrances, different input patterns as well as distribution patterns are relevant, though the river Elbe is still a major source of pollution to the German Bight of the North Sea. The data seem to indicate either relevant inputs further west of the sampling area or mobilization from the sediments.

  3. Invasion of Asian tiger shrimp, Penaeus monodon Fabricius, 1798, in the western north Atlantic and Gulf of Mexico

    USGS Publications Warehouse

    Fuller, Pam L.; Knott, David M.; Kingsley-Smith, Peter R.; Morris, James A.; Buckel, Christine A.; Hunter, Margaret E.; Hartman, Leslie D.

    2014-01-01

    After going unreported in the northwestern Atlantic Ocean for 18 years (1988 to 2006), the Asian tiger shrimp, Penaeus monodon, has recently reappeared in the South Atlantic Bight and, for the first time ever, in the Gulf of Mexico. Potential vectors and sources of this recent invader include: 1) discharged ballast water from its native range in Asia or other areas where it has become established; 2) transport of larvae from established non-native populations in the Caribbean or South America via ocean currents; or 3) escape and subsequent migration from active aquaculture facilities in the western Atlantic. This paper documents recent collections of P. monodon from the South Atlantic Bight and the Gulf of Mexico, reporting demographic and preliminary phylogenetic information for specimens collected between North Carolina and Texas from 2006 through 2012. The increased number of reports in 2011 and 2012, ranging from 102 mm to 298 mm total length, indicates that an adult population is present in densities sufficient for breeding, which is indicative of incipient establishment. Based on these reports of P. monodon, its successful invasion elsewhere, and its life history, we believe that this species will become common in the South Atlantic Bight and Gulf of Mexico in less than 10 years. Penaeus monodon is an aggressive predator in its native range and, if established, may prey on native shrimps, crabs, and bivalves. The impacts of an established P. monodon population are potentially widespread (e.g., alterations in local commercial fisheries, direct and indirect pressures on native shrimp, crab and bivalve populations, and subsequent impacts on the populations of other predators of those organisms) and should be considered by resource managers. The impacts of P. monodon on native fauna and the source(s) or vector(s) of the invasion, however, remain unknown at this time.

  4. Calculation of UV attenuation and colored dissolved organic matter absorption spectra from measurements of ocean color

    NASA Astrophysics Data System (ADS)

    Johannessen, S. C.; Miller, W. L.; Cullen, J. J.

    2003-09-01

    The absorption of ultraviolet and visible radiation by colored or chromophoric dissolved organic matter (CDOM) drives much of marine photochemistry. It also affects the penetration of ultraviolet radiation (UV) into the water column and can confound remote estimates of chlorophyll concentration. Measurements of ocean color from satellites can be used to predict UV attenuation and CDOM absorption spectra from relationships between visible reflectance, UV attenuation, and absorption by CDOM. Samples were taken from the Bering Sea and from the Mid-Atlantic Bight, and water types ranged from turbid, inshore waters to the Gulf Stream. We determined the following relationships between in situ visible radiance reflectance, Lu/Ed (λ) (sr-1), and diffuse attenuation of UV, Kd(λ) (m-1): Kd(323nm) = 0.781[Lu/Ed(412)/Lu/Ed(555)]-1.07; Kd(338nm) = 0.604[Lu/Ed(412)/Lu/Ed(555)]-1.12; Kd(380 nm) = 0.302[Lu/Ed(412)/Lu/Ed(555)]-1.24. Consistent with published observations, these empirical relationships predict that the spectral slope coefficient of CDOM absorption increases as diffuse attenuation of UV decreases. Excluding samples from turbid bays, the ratio of the CDOM absorption coefficient to Kd is 0.90 at 323 nm, 0.86 at 338 nm, and 0.97 at 380 nm. We applied these relationships to SeaWiFS images of normalized water-leaving radiance to calculate the CDOM absorption and UV attenuation in the Mid-Atlantic Bight in May, July, and August 1998. The images showed a decrease in UV attenuation from May to August of approximately 50%. We also produced images of the areal distribution of the spectral slope coefficient of CDOM absorption in the Georgia Bight. The spectral slope coefficient increased offshore and changed with season.

  5. A numerical simulation of the Catalina Eddy

    SciTech Connect

    Ueyoshi, Kyozo; Roads, J.O.; Alpert, J.

    1991-12-31

    A shallow cyclonic eddy termed the Catalina Eddy has occasionally been observed during summer in the bight of southern California. The Catalina Eddy occurs within {approximately}100 km from the coastal mountains with a depth typically extending up to the marine inversion level of several hundred meters above sea level and a diameter on the order of 100--200 km. The Catalina Eddy is produced by the interaction between the synoptic-scale northerly flow and the formidable topography along the southern California coast. A favorable synoptic situation that enhances the increased low-level climatological northerly flow along the central California coastline is the presence of the prominent east-west pressure gradient between the subtropical East Pacific high and the inland thermal low over California. Increased northerlies impinging on the San Rafael mountains north of Santa Barbara result in enhanced mesoscale lee troughing in the bight and establishment of a narrow ridge alongshore, leading to establishment of cyclonic vorticity in the bight. This paper describes numerical simulations and predictions of a Catalina Eddy event with a high-resolution multi-level limited area model. The model is initialized and forced at the lateral boundaries by the National Meteorological Center`s (NMC) 2.5{degree} {times} 2.5{degree} global objective analysis and also by NMC`s medium range forecast model (MRF) 1--10 day forecasts. In the authors previous effort to simulate mesoscale disturbances such as the Catalina Eddy the integrations were performed up to 1 model-day utilizing the NMC analysis as fixed lateral boundary conditions. In this paper they describe the results of continuous 5- to 7-day simulations of the Catalina Eddy event of 26--30 June 1988 by utilizing time-dependent lateral boundary conditions obtained from NMC`s global objective analysis as well as NMC`s MRF forecasts.

  6. Mollusk-isotope records of Plio-Pleistocene marine paleoclimate, U. S. Middle Atlantic Coastal Plain

    SciTech Connect

    Krantz, D.E. )

    1990-08-01

    Stable oxygen and carbon isotope profiles from fossil scallop shells provide detailed paleoenvironmental information for the Pliocene and early Pleistocene of the Middle Atlantic Coastal Plain. Scallop specimens were collected from strata which represent at least five major marine transgressions. Minimum and maximum paleotemperatures were calculated from the {delta}{sup 18}O ranges recorded in each shell profile, after adjusting for changes in seawater {delta}{sup 18}O related to changes in global ice volume. Paleotemperature ranges from each stratigraphic unit were compared with modern conditions on the shelves of the Middle and South Atlantic Bight, and with paleotemperatures estimated by Hazel (1971b, 1988) from the ostracode faunas. The mollusk-isotope records indicate that the marine climate of the Atlantic Shelf was mild temperate during the deposition of the Sunken Meadow Member of the Yorktown Formation in the early Pliocene. The climate became warm temperate during the middle and late Pliocene transgressions which deposited the Rushmere, Morgarts Beach and Moore House Members of the Yorktown Formation and the Chowan River Formation. During the deposition of the James City Formation in the early Pleistocene, temperatures returned to a mild temperate climate similar to that of the modern Virginia Bight shelf. The character of the isotope profiles indicates that hydrographic conditions were generally stable and similar to those of the modern Middle Atlantic Bight. The {delta}{sup 13}C profiles of most of the shells show trends suggestive of spring phytoplankton blooms and summer water-column stratification. Anomalies in several profiles are interpreted as reduced salinity events, probably related to river discharge, which most commonly occur in the spring. There is no convincing evidence in the shell profiles for upwelling.

  7. Risk, mercury levels, and birds: relating adverse laboratory effects to field biomonitoring.

    PubMed

    Burger, J; Gochfeld, M

    1997-11-01

    There is an abundance of field data on levels of mercury in a variety of organisms and there are a number of studies that demonstrate the adverse effects of mercury on laboratory animals, but few studies examine the relationship between the two. Thus it is often difficult to determine the ecological relevance of mercury concentrations found in nature, or to predict the ecosystem consequences of current levels. In this paper we review the levels in tissues that are associated with adverse effects in birds from laboratory studies and compare these with levels found in wild bird populations in the New York Bight to provide a basis for interpreting values in avian populations. We use feathers from fledgling birds which would have been fed on locally obtained food to eliminate the problem of where toxic burdens were acquired by more mobile adult birds. Laboratory studies indicate that in some species mercury levels of 1.5 ppm in eggs and/or 5 to 40 ppm in the feathers of birds are associated with adverse effects, including impaired reproduction. We report egg levels in birds that range as high as 3.8 ppm and feather levels that range as high as 10.3 ppm, although means are much lower. The levels in eggs of some wild birds in the New York Bight are within the range known to lower hatchability, embryo and chick survival, and chick weight, all variables that reduce reproductive success. Species with high egg levels include Forster's tern (Sterna forsteri) and black skimmer (Rynchops niger). Levels in feathers of some young wild birds from the New York Bight are within the range associated with reduced hatchability of eggs, behavioral abnormalities of adults, and infertility. Species with dangerously elevated mercury levels in feathers include great egret (Ardea [=Egretta] alba), snowy egret [Egretta thula), and black skimmers.

  8. The imprint of the Slave Trade in an African American population: mitochondrial DNA, Y chromosome and HTLV-1 analysis in the Noir Marron of French Guiana

    PubMed Central

    2010-01-01

    Background Retracing the genetic histories of the descendant populations of the Slave Trade (16th-19th centuries) is particularly challenging due to the diversity of African ethnic groups involved and the different hybridisation processes with Europeans and Amerindians, which have blurred their original genetic inheritances. The Noir Marron in French Guiana are the direct descendants of maroons who escaped from Dutch plantations in the current day Surinam. They represent an original ethnic group with a highly blended culture. Uniparental markers (mtDNA and NRY) coupled with HTLV-1 sequences (env and LTR) were studied to establish the genetic relationships linking them to African American and African populations. Results All genetic systems presented a high conservation of the African gene pool (African ancestry: mtDNA = 99.3%; NRY = 97.6%; HTLV-1 env = 20/23; HTLV-1 LTR = 6/8). Neither founder effect nor genetic drift was detected and the genetic diversity is within a range commonly observed in Africa. Higher genetic similarities were observed with the populations inhabiting the Bight of Benin (from Ivory Coast to Benin). Other ancestries were identified but they presented an interesting sex-bias. Whilst male origins spread throughout the north of the bight (from Benin to Senegal), female origins were spread throughout the south (from the Ivory Coast to Angola). Conclusions The Noir Marron are unique in having conserved their African genetic ancestry, despite major cultural exchanges with Amerindians and Europeans through inhabiting the same region for four centuries. Their maroon identity and the important number of slaves deported in this region have maintained the original African diversity. All these characteristics permit to identify a major origin located in the former region of the Gold Coast and the Bight of Benin; regions highly impacted by slavery, from which goes a sex-biased longitudinal gradient of ancestry. PMID:20958967

  9. New Thought on the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Meyer, A. A.; Lutjeharms, J. R.; Whittle, C.; Weeks, S.; Roy, C.

    2002-12-01

    A more complete understanding of the fundamental dynamics of the Agulhas Current Proper is evolving rapidly because of new discoveries. The discovery of the Agulhas Undercurrent (Beal and Bryden, 1997) had a profound effect on the overall estimate of the Agulhas Current transport. Also, the discovery of Schouten et al. (2002) that Mozambique Channel Eddies are responsible for the formation of Natal Pulses, which in turn is significantly related to the Indian-Atlantic Interocean leakage of water masses, had a profound effect on how the Agulhas Current System is now perceived. These new insights, historical hydrographic data, and satellite remote sensed data contributed to the formulation of 3 hypotheses on the fundamental dynamics of the Agulhas Current Proper. Hypothesis one: Directly north of the Delagoa Bight the Mozambique Channel Eddies encounter the most northern extend of the shallow Agulhas Current and interact with the seaward side of this Western Boundary Current to form the Delagoa Pulse, obtaining its required cyclonicity from the Delagoa Bight Lee Eddy. Hypothesis two: Water masses of the Agulhas Undercurrent and Red Sea Water are upwelled within the Delagoa Bight Lee eddy which forms the southward propagating Delagoa Pulse. Hence, parts of the Agulhas Undercurrent are transported back into the Atlantic Ocean via a fast-track (10 to 20 km/day) mechanism, the Delagoa Pulse. Hypothesis three: Delagoa Pulses act as mechanisms for the injection of upwelled Agulhas Undercurrent water masses and Red Sea Water onto the eastern Agulhas Bank, supplying a semi-continuous density flow along the 100 m isobath. This density current originates from the Indian Ocean sector of the Agulhas Bank at the Port Alfred Upwelling Cell, feeds the cold bottom ridge, rounds the Alphard Banks, and enters the Atlantic Ocean sector of the Agulhas Bank. The physical and chemical properties of the density flow coined the Lutjeharms (Indian-Atlantic Interocean secondary leakage) Return

  10. Modelling the fate of the Tijuana River discharge plume

    NASA Astrophysics Data System (ADS)

    van Ormondt, M.; Terrill, E.; Hibler, L. F.; van Dongeren, A. R.

    2010-12-01

    After rainfall events, the Tijuana River discharges excess runoff into the ocean in a highly turbid plume. The runoff waters contain large suspended solids concentrations, as well as high levels of toxic contaminants, bacteria, and hepatitis and enteroviruses. Public health hazards posed by the effluent often result in beach closures for several kilometers northward along the U.S. shoreline. A Delft3D model has been set up to predict the fate of the Tijuana River plume. The model takes into account the effects of tides, wind, waves, salinity, and temperature stratification. Heat exchange with the atmosphere is also included. The model consists of a relatively coarse outer domain and a high-resolution surf zone domain that are coupled with Domain Decomposition. The offshore boundary conditions are obtained from the larger NCOM SoCal model (operated by the US Navy) that spans the entire Southern California Bight. A number of discharge events are investigated, in which model results are validated against a wide range of field measurements in the San Diego Bight. These include HF Radar surface currents, REMUS tracks, drifter deployments, satellite imagery, as well as current and temperature profile measurements at a number of locations. The model is able to reproduce the observed current and temperature patterns reasonably well. Under calm conditions, the model results suggest that the hydrodynamics in the San Diego Bight are largely governed by internal waves. During rainfall events, which are typically accompanied by strong winds and high waves, wind and wave driven currents become dominant. An analysis will be made of what conditions determine the trapping and mixing of the plume inside the surfzone and/or the propagation of the plume through the breakers and onto the coastal shelf. The model is now also running in operational mode. Three day forecasts are made every 24 hours. This study was funded by the Office of Naval Research.

  11. ROMS and SUNTANS Continued Development and Support of AESOP And NLIWI

    DTIC Science & Technology

    2007-09-30

    International Conference on the Humboldt Current System, Lima/Peru, Dec. 2006. Deutsch, C. N. Gruber, H. Frenzel , T. Nagai, G.-K. Plattner, J.C. McWilliams, A...Stolzenbach, 2007: Circulation in the Southern California Bight. Eastern Pacific Ocean Conference, Leavenworth, WA, Sept. 2007. Frenzel , H., C. Dong, N. Gruber...Sept. 2006. Gruber, N., H. Frenzel , P. Marchesiello, J.C. McWilliams, T. Nagai, and G.-K. Plattner, 2007: On the Role of Eddies for Coastal Productivity

  12. Quantitative mapping of chlorophyll a distributions in coastal zones by remote sensing

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.

    1977-01-01

    Results of experiments conducted in the James River, Virginia and the New York Bight indicate that concurrently collected sea-truth measurements may be used to calibrate remotely sensed multispectral scanner data collected over each of these environmentally different scenes. Statistical stepwise regression analysis was used in both experiments to incorporate significant bands of MSS data into regression equations that quantitatively relate remotely sensed data to water quality parameters, such as chlorophyll a and suspended sediment. These regression equations are used to map synoptic distributions of chlorophyll a in the remotely sensed scenes.

  13. Improving the Navy’s Passive Underwater Acoustic Monitoring of Marine Mammal Populations

    DTIC Science & Technology

    2014-09-30

    call propagation (as in Helble et al., 2013a) is being conducted at a number of “High-frequency Acoustic Recording Package” ( HARP ) monitoring sites...propagation can occur (e.g., at Hoke Seamount). Humpback calls are detected in the HARP data collected at these sites using the Generalized Power Law (GPL...Numerical modeling out to 100 km range in 1-deg azimuthal steps and 10-m steps in depth is being conducted for 6 HARP sites in the Southern California Bight

  14. A Numerical Study of the Plata River Plume Along the Southeastern South American Continental Shelf

    DTIC Science & Technology

    2005-01-01

    Form Approved 0 JOMB No. 0704-0188 A1e public reporting burden for this collection of information is estimated to average 1 hour per response...Ocean Model 1 .SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON ". REPORT b. ABSTRACT c. THIS PAGE ABSTRACT OF...middle of the bight, at approximately nearly 20% of South America. The influence of its 23󈧢’S (Fig. 1 ). The absence of major river systems plume

  15. Hookworm enteritis with bacteremia in California sea lion pups on San Miguel Island.

    PubMed

    Spraker, Terry R; DeLong, Robert L; Lyons, Eugene T; Melin, Sharon R

    2007-04-01

    Large breeding populations of California sea lions (Zalophus californianus) are located on San Miguel and San Nicolas Islands in the Southern California Bight. In 2001, there was a substantial increase in pup mortality in late summer and fall. From June 2002 to January 2003, 208 freshly dead pups were examined on San Miguel Island, the most western of the Channel Islands off the coast of southern California. Tissues from 186 of these pups were examined histologically. The primary lesions in 133 (72%) of the pups were an enteritis associated with hookworms and infections in major organs. Emaciation/starvation in 43 pups (26%) was the second most important cause of death.

  16. Multispectral analysis of ocean dumped materials

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.

    1977-01-01

    Remotely sensed data were collected in conjunction with sea-truth measurements in three experiments in the New York Bight. Pollution features of primary interest were ocean dumped materials, such as sewage sludge and acid waste. Sewage-sludge and acid-waste plumes, including plumes from sewage sludge dumped by the 'line-dump' and 'spot-dump' methods, were located, identified, and mapped. Previously developed quantitative analysis techniques for determining quantitative distributions of materials in sewage sludge dumps were evaluated, along with multispectral analysis techniques developed to identify ocean dumped materials. Results of these experiments and the associated data analysis investigations are presented and discussed.

  17. Nutrients in waters on the inner shelf between Cape Charles and Cape Hatteras

    NASA Technical Reports Server (NTRS)

    Wong, G. T. F.; Todd, J. F.

    1981-01-01

    The distribution of nutrients in the shelf waters of the southern tip of the Middle Atlantic Bight was investigated. It is concluded that the outflow of freshwater from the Chesapeake Bay is a potential source of nutrients to the adjacent shelf waters. However, a quantitative estimation of its importance cannot yet be made because (1) there are other sources of nutrients to the study area and these sources cannot yet be quantified and (2) the concentrations of nutrients in the outflow from Chesapeake Bay exhibit significant short-term and long-term temporal variabilities.

  18. Current-wave interaction in the Mississippi-Atchafalaya river plume on the Texas-Louisiana shelf

    NASA Astrophysics Data System (ADS)

    Rong, Zengrui; Hetland, Robert D.; Zhang, Wenxia; Zhang, Xiaoqian

    2014-12-01

    Wave-current interaction over the Texas-Louisiana shelf, and its effects on the dispersal and mixing of the Mississippi-Atchafalaya river plume, have been investigated using the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System. The modeling system is driven by realistic wave and current conditions at the open boundaries and high frequency1-D wind measured from a nearby meteorological station. Skill analysis demonstrates that the model reproduces the wave and salinity fields reasonably well. Waves over the Texas-Louisiana shelf are dominated by locally forced wind seas, and generally propagate in the same direction as the winds. Investigation into the spatial differences in the effect of waves reveals two distinct dynamical regions: the Chenier shelf, the shelf region extending roughly offshore from Sabine Lake to Vermilion Bay, and the Louisiana Bight, the region between the Mississippi Delta and Terrebonne Bay. A variety of model runs are performed, where specific wave processes are either included or excluded, in order to isolate the processes acting in different regions. The Chenier shelf is mainly affected by wave enhanced bottom stress, whereas the Louisiana Bight is mostly affected by the surface wave induced mixing and 3-D wave forces. The wave enhanced bottom stress suppresses cross-shore exchange, and acts to trap more freshwater in the nearshore regions shallower than 50 m over the Chenier shelf. Wave enhanced bottom stress plays only a minor role in the Louisiana Bight, where the surface-trapped Mississippi plume rarely feels the bottom. The surface intensified wave mixing and 3-D wave forces reduce the surface salinity and weaken the stratification in the region associated with the thin recirculating Mississippi plume in the Louisiana Bight. Model results indicate that the surface wave mixing, the 3-D wave forces, and the wave bottom stress exhibit little interaction over the Texas-Louisiana shelf. Finally, we have demonstrated

  19. Energy-related perturbations of the northeast coastal zone: five years (1974-1979) of oceanographic research at Brookhaven National Laboratory

    SciTech Connect

    Walsh, J.J.

    1980-03-01

    Since inception of oceanographic research at Brookhaven National Laboratory in 1974, over 75 cruises and 150 papers and reports have been completed. In comparison of shelf ecosystems at high, mid, and low latitudes, an understanding of the natural variability of US coastal waters has been derived. Annual carbon and nitrogen budgets suggest that the energy flow is diverted to a pelagic food web in summer-fall and a demersal food web in winter-spring within the Mid-Atlantic Bight. The impact of energy-related perturbations can now be assessed within the context of natural oscillation of the coastal food web.

  20. A Community Terrain-Following Ocean Modeling System (ROMS/TOMS)

    DTIC Science & Technology

    2010-09-30

    Di Lorenzo (Southern California predictability) at Georgia Institute of Oceanography, and J. Wilkin (Mid-Atlantic Bight variational data assimilation...10.1029/2005GB002456. Fiechter, J., A.M. Moore, C.A. Edwards, K.W. Bruland, E. Di Lorenzo , C.V.W Lewis, T.M. Powell, E. Curchitser, and K. Hedstrom...D.B., H. Arango, W.P. Budgell, B.D. Cornuelle, E. Curchitser, E. Di Lorenzo , K. Fennel, W.R. Geyer, A.J. Hermann, L. Lanerolle, J. Levin, J.C

  1. A Community Terrain-Following Ocean Modeling System (ROMS/TOMS)

    DTIC Science & Technology

    2012-09-30

    Lorenzo (Southern California predictability) at Georgia Institute of Oceanography, and J. Wilkin (Mid-Atlantic Bight variational data assimilation...Fiechter, J., A.M. Moore, C.A. Edwards, K.W. Bruland, E. Di Lorenzo , C.V.W Lewis, T.M. Powell, E. Curchitser, and K. Hedstrom, 2009: Modeling iron...Budgell, B.D. Cornuelle, E. Curchitser, E. Di Lorenzo , K. Fennel, W.R. Geyer, A.J. Hermann, L. Lanerolle, J. Levin, J.C. McWilliams, A.J. Miller, A.M

  2. DRI internal Wave Simulations

    DTIC Science & Technology

    2005-01-01

    Acoust. Soc. Am., 93, 1736–1742 (1993). Ericksen, C. C., T. J. Osse, R. D. Light, T. Wen, T. W. Lehman, P. L. Sabin, J. W. Ballard, and A. M . Chiodi ...profiles were then low-pass filtered to remove high wave number variability. Typically, below the mixed layer, length scales smaller than 20–30 m were...Atlantic Bight location (39.25°N, 72.4°W) was 200 m with a sandy bottom. For the acoustic geometry a point source at 50 m with 20 km range was assumed

  3. Circulation and exchange at the continental shelf and slope, SEEP-II

    SciTech Connect

    Houghton, R.W.; Ou, Hsien-Wang.

    1990-01-01

    This project is a component of the SEEP-2 program to study shelf-slope exchange in the southern Middle Atlantic bight (MBA). It represents the physical oceanographic portion of the SEEP-2 research at Lamont-Doherty Geological Observatory (L-DGO). Since the work consists of two parts: data analysis and theoretical modeling, this report will be divided into two parts to describe the progress of each activity. It covers work performed during the time interval March to December 1990 and is a sequel to the report submitted in February 1990. 25 figs.

  4. Current Laminar Flow Control Experiments at NASA Dryden

    NASA Technical Reports Server (NTRS)

    Bowers, Al

    2010-01-01

    An experiment to demonstrate laminar flow over the swept wing of a subsonic transport is being developed. Discrete Roughness Elements are being used to maintain laminar flow over a substantial portion of a wing glove. This passive laminar flow technology has only come to be recognized as a significant player in airliner drag reduction in the last few years. NASA is implementing this experiment and is planning to demonstrate this technology at full-scale Bight cruise conditions of a small-to-medium airliner.

  5. Ocean color spectral variability studies using solar-induced chlorophyll fluorescence

    NASA Technical Reports Server (NTRS)

    Hoge, Frank E.; Swift, Robert N.

    1987-01-01

    It is suggested that chlorophyll-induced ocean color spectral variability can be studied using only a passive airborne spectroradiometer instrument, with solar-induced chlorophyll fluorescence used as the standard against which all correlations are performed. The intraspectral correlation (ISC) method is demonstrated with results obtained during an airborne mapping mission in the New York Bight. The curvature algorithm is applied to the solar-induced chlorophyll fluorescence at about 690 nm, and good agreement is found with results obtained using active-passive correlation spectroscopy. The ISC method has application to spectral variability and resulting chlorophyll concentration measurement in different environmental conditions and in different water types.

  6. Large-scale genotoxicity assessments in the marine environment.

    PubMed Central

    Hose, J E

    1994-01-01

    There are a number of techniques for detecting genotoxicity in the marine environment, and many are applicable to large-scale field assessments. Certain tests can be used to evaluate responses in target organisms in situ while others utilize surrogate organisms exposed to field samples in short-term laboratory bioassays. Genotoxicity endpoints appear distinct from traditional toxicity endpoints, but some have chemical or ecotoxicologic correlates. One versatile end point, the frequency of anaphase aberrations, has been used in several large marine assessments to evaluate genotoxicity in the New York Bight, in sediment from San Francisco Bay, and following the Exxon Valdez oil spill. PMID:7713029

  7. Atlantic Coastal experiment III, FRV Delaware II cruise, 17-27 May 1977 and R/V ONRUST cruise, 28-30, June 1977. Data report

    SciTech Connect

    Malloy, S.; Stoddard, A.; von Bock, K.

    1980-09-01

    The DELAWARE II and ONRUST cruises, continuations of Atlantic Coastal Experiment III, were made during May and late June, 1977, to compare seasonal changes in chlorophyll a, nitrogen nutrient, dissolved oxygen and phytoplankton composition within the mid-Atlantic and New York Bights. Data from 106 stations and 3300 km of surface mapping are reported as classical hydrographic listings, areal and/or vertical contours of chlorophyll a, inorganic nitrogen and salinity, and listings of phytoplankton species abun- dance. Temperature profiles from 100 stations are included, as well as res- piration experiments [ETS assay] for the dinoflagellate, Ceratium tripos.

  8. Large-scale genotoxicity assessments in the marine environment

    SciTech Connect

    Hose, J.E.

    1994-12-01

    There are a number of techniques for detecting genotoxicity in the marine environment, and many are applicable to large-scale field assessments. Certain tests can be used to evaluate responses in target organisms in situ while others utilize surrogate organisms exposed to field samples in short-term laboratory bioassays. Genotoxicity endpoints appear distinct from traditional toxicity endpoints, but some have chemical or ecotoxicologic correlates. One versatile end point, the frequency of anaphase aberrations, has been used in several large marine assessments to evaluate genotoxicity in the New York Bight, in sediment from San Francisco Bay, and following the Exxon Valdez oil spill. 31 refs., 2 tabs.

  9. Shelf edge exchange processes-II SEEP2-06, R/V Endeavor cruise 186

    SciTech Connect

    Wilson, C.; Behrens, W.J.; Flagg, C.N.; Wallace, D.W.R.; Wilke, R.J.; Wyman, K.D.

    1989-12-01

    The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. Phase I of SEEP consisted of a series of nine cruises and a mooring array across the outer continental shelf of New England during 1983--1984. Phase II focused specifically on the shelf/slope frontal region of the mid-Atlantic bight off the Delmarva Peninsula. Hydrographic data were collected on eight of the six cruises.

  10. Ocean Pollution Research Center

    SciTech Connect

    Not Available

    1994-10-01

    The Ocean Pollution Research Center (OPRC) is a University of Miami center based at the Rosenstiel School of Marine and Atmospheric Science (RSMAS) and with significant involvement by the College of Engineering. It was formed in 1992 out of concerns for potential oil spills placing at risk the fragile ecosystems of the Florida Keys. OPRC's scope also includes the Caribbean Sea, Gulf of Mexico, and the South Atlantic Bight. Focus is on the physical transport of oil spills and information management for response operations. Studies of the fates and effects of oil spills are also undertaken.

  11. Relationships between chlorophyll density and ocean radiance as measured by U2/OCS: Algorithms, examples and comparison

    NASA Technical Reports Server (NTRS)

    Kim, H. H.; Hart, W. D.

    1983-01-01

    An ocean atmosphere radiative transfer process computation method which is suitable for determining lower boundary ocean albedo and other radiation components from spectral measurements of upwelling radiance taken from a high altitude platform is described. The method was applied to a set of color scanner data taken from slope water of the South Atlantic Bight to determine the influence of cholorophyll-a pigments in the sea on the ratio of upwelling radiance to down welling irradiance as a function of wavelength. The resulting chlorophyll concentrations are compared with measurements made by ships stationed along the flight path.

  12. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic). Spot

    DTIC Science & Technology

    1989-02-01

    1978. Development of the northwestern Gulf of Mexico (May fishes in the Mid-Atlantic Bight. 1985). M.S. Thesis. Texas A&M Vol. IV. Carangidae through... Laguna Madre , a hypersaline estuary. Pages 383-389 Joseph, E.B. 1972. The status of in G. H. Lauff, ed. Estuaries, the sciaenid stocks of the Middle...Fisheries, other commercial sciaenids of the Morehead City, N.C. 80 pp. Texas Gulf. Bull. U.S. Bur. Fish . 44:129-214. Stickney, R.R., and M.L. Cuenco

  13. Shelf edge exchange processes-II SEEP2-06, R/V Endeavor cruise 186. Hydrographic data report

    SciTech Connect

    Wilson, C.; Behrens, W.J.; Flagg, C.N.; Wallace, D.W.R.; Wilke, R.J.; Wyman, K.D.

    1989-12-01

    The Shelf Edge Exchange Processes (SEEP) program sponsored by the United States Department of Energy is a multi-institutional effort designed to investigate the flux of suspended material from the continental shelf to the waters of the upper slope, and then possibly into the slope sediments. Phase I of SEEP consisted of a series of nine cruises and a mooring array across the outer continental shelf of New England during 1983--1984. Phase II focused specifically on the shelf/slope frontal region of the mid-Atlantic bight off the Delmarva Peninsula. Hydrographic data were collected on eight of the six cruises.

  14. Gulf stream separation dynamics

    NASA Astrophysics Data System (ADS)

    Schoonover, Joseph

    Climate models currently struggle with the more traditional, coarse ( O(100 km) ) representation of the ocean. In these coarse ocean simulations, western boundary currents are notoriously difficult to model accurately. The modeled Gulf Stream is typically seen exhibiting a mean pathway that is north of observations, and is linked to a warm sea-surface temperature bias in the Mid-Atlantic Bight. Although increased resolution ( O(10 km) ) improves the modeled Gulf Stream position, there is no clean recipe for obtaining the proper pathway. The 70 year history of literature on the Gulf Stream separation suggests that we have not reached a resolution on the dynamics that control the current's pathway just south of the Mid-Atlantic Bight. Without a concrete knowledge on the separation dynamics, we cannot provide a clean recipe for accurately modeling the Gulf Stream at increased resolutions. Further, any reliable parameterization that yields a realistic Gulf Stream path must express the proper physics of separation. The goal of this dissertation is to determine what controls the Gulf Stream separation. To do so, we examine the results of a model intercomparison study and a set of numerical regional terraforming experiments. It is argued that the separation is governed by local dynamics that are most sensitive to the steepening of the continental shelf, consistent with the topographic wave arrest hypothesis of Stern (1998). A linear extension of Stern's theory is provided, which illustrates that wave arrest is possible for a continuously stratified fluid.

  15. Genetic differentiation of brackish water populations of cod Gadus morhua in the southern Baltic, inferred from genotyping using SNP-arrays.

    PubMed

    Poćwierz-Kotus, A; Kijewska, A; Petereit, C; Bernaś, R; Więcaszek, B; Arnyasi, M; Lien, S; Kent, M P; Wenne, R

    2015-02-01

    The Baltic is a semi-enclosed sea characterised by decreasing salinity in the eastern and northern direction with only the deeper parts of the southern Baltic suitable as spawning grounds for marine species like cod. Baltic cod exhibits various adaptations to brackish water conditions, yet the inflow of salty North Sea water near the bottom remains an influence on the spawning success of the Baltic cod. The eastern Baltic population has been very weakly studied in comparison with the western population. The aim of this study is to demonstrate for the first time genetic differentiation by the use of a large number of SNPs between eastern and western Baltic populations existing in differentiated salinity conditions. Two cod samples were collected from the Bay of Gdańsk, Poland and one from the Kiel Bight, Germany. Samples were genotyped using a cod derived SNP-array (Illumina) with 10 913 SNPs. A selection of diagnostic SNPs was performed. A set of 7944 validated SNPs were analysed to assess the differentiation of three samples of cod. Results indicated a clear distinctness of the Kiel Bight from the populations of the eastern Baltic. FST comparison between both eastern samples was non-significant. Clustering analysis, principal coordinates analysis and assignment test clearly indicated that the eastern samples should be considered as one subpopulation, well differentiated from the western subpopulation. With the SNP approach, no differentiation between groups containing 'healthy' and 'non-healthy' cod individuals was observed.

  16. Assessment of some innate immune responses in dab (Limanda limanda L.) from the North Sea as part of an integrated biological effects monitoring

    NASA Astrophysics Data System (ADS)

    Skouras, Andreas; Lang, Thomas; Vobach, Michael; Danischewski, Dirk; Wosniok, Werner; Scharsack, Jörn Peter; Steinhagen, Dieter

    2003-10-01

    The marine flatfish dab (Limanda limanda), which lives in direct contact with contaminated sediments, is frequently used as a sentinel species in international monitoring programmes on the biological effects of contaminants. In this study, immune responses were recorded as indicators of sublethal chronic effects of contaminants, in addition to measurement of the induction of mono-oxygenase ethoxyresorufin O-deethylase (EROD) in liver cells, the inhibition of acetylcholin esterase (AChE) in muscle and a quantification of grossly visible diseases and parasites. In total, 336 dab were analysed from five sampling areas in the North Sea, including the German Bight, the Dogger Bank, the Firth of Forth, and two locations close to oil and gas platforms (Ekofisk and Danfield). When considering plasma lysozyme levels, pinocytosis and respiratory burst activity of head kidney leucocytes, a clear gradient could be observed with decreased levels in individuals collected from the Firth of Forth and locations near the oil or gas platforms compared with dab from the Dogger Bank or the German Bight. Individuals with induced EROD activity displayed reduced lysozyme and respiratory burst activities. Lysozyme levels were also reduced in dab with lymphocystis or with nematodes. The data obtained indicate that the assessment of innate immune parameters in a monitoring programme provides supplementary information about immunomodulatory effects associated with the exposure of fish to contaminants. In particular, concentrations of plasma lysozyme, which can be analysed in an easy and inexpensive assay, are considered to be an appropriate parameter for use in a battery of other bioindicators.

  17. Detecting small-scale horizontal gradients in the upper ocean using wavelet analysis

    NASA Astrophysics Data System (ADS)

    North, Ryan P.; Riethmüller, Rolf; Baschek, Burkard

    2016-10-01

    Mesoscale and submesoscale eddies and fronts in the upper ocean are often closely coupled with biogeochemical processes. Improved instrumentation provides high-resolution data in both the horizontal and vertical capturing this large range of scales (1-100 km), but novel analysis methods are still needed to take full advantage of this advancement. A new method using wavelet analysis is therefore proposed to identify the horizontal scales at which biophysical interactions occur, defined by concurrent fluctuations in temperature and phytoplankton patchiness. The method is applied to temperature and chlorophyll-a fluorescence data measured in the North Sea's German Bight during early spring using a towed undulating vehicle. The wavelet analysis identified the scale and location of individual features characterized by horizontal gradients of temperature and chlorophyll-a fluorescence. Applied to multiple transects, the method can also retrieve the statistics of relevant biophysical scales in a particular region. The combined analysis of seven transects suggests that physical and biogeochemical tracers tend to align at scales of 3-15 km in the German Bight, highlighting the likely relevance of submesoscale processes in this region. In general, the proposed wavelet analysis method is shown to be a robust tool for the analysis of biophysical interactions across a range of scales.

  18. Satellite Remote Sensing Studies of Biological and Biogeochemical Processing in the Ocean

    NASA Technical Reports Server (NTRS)

    Vernet, Maria

    2001-01-01

    The remote sensing of phycoerythrin-containing phytoplankton by ocean color was evaluated. Phycoerythrin (PE) can be remotely sensed by three methods: surface reflectance (Sathyendranath et al. 1994), by laser-activated fluorescence (Hoge and Swift 1986) and by passive fluorescence (Letelier et al. 1996). In collaboration with Dr. Frank Hoge and Robert Swift during Dr. Maria Vernet's tenure as Senior Visiting Scientist at Wallops Island, the active and passive methods were studied, in particular the detection of PE fluorescence and spectral reflectance from airborne LIDAR (AOL). Airborne instrumentation allows for more detailed and flexible sampling of the ocean surface than satellites thus providing the ideal platform to test model and develop algorithms than can later be applied to ocean color by satellites such as TERRA and AQUA. Dr. Vernet's contribution to the Wallops team included determination of PE in the water column, in conjunction with AOL flights in the North Atlantic Bight. In addition, a new flow-through fluorometer for PE determination by fluorescence was tested and calibrated. Results: several goals were achieved during this period. Cruises to the California Current, North Atlantic Bight, Gulf of Maine and Chesapeake Bay provided sampling under different oceanographic and optical conditions. The ships carried the flow-through fluorometer and samples for the determination of PE were obtained from the flow-through flow. The AOL was flown over the ship's track, usually several flights during the cruise, weather permitting.

  19. A novel adaptive biogeochemical model, and its 3-D application for a decadal hindcast simulation of the biogeochemistry of the southern North Sea

    NASA Astrophysics Data System (ADS)

    Kerimoglu, Onur; Hofmeister, Richard; Wirtz, Kai

    2016-04-01

    Adaptation and acclimation processes are often ignored in ecosystem-scale model implementations, despite the long-standing recognition of their importance. Here we present a novel adaptive phytoplankton growth model where acclimation of the community to the changes in external resource ratios is accounted for, using optimality principles and dynamic physiological traits. We show that the model can reproduce the internal stoichiometries obtained at marginal supply ratios in chemostat experiments. The model is applied in a decadal hindcast simulation of the southern North Sea, where it is coupled to a 2-D benthic model and a 3-D hydrodynamic model in an approximately 1.5km horizontal resolution at the German Bight coast. The model is shown to have good skill in capturing the steep, coastal gradients in the German Bight, suggested by the match between the estimated and observed dissolved nutrient and chlorophyll concentrations. We then analyze the differential sensitivity of the coastal and off-shore zones to major drivers of the system, such as riverine nutrient loads. We demonstrate that the relevance of phytoplankton acclimation varies across coastal gradients and can become particularly significant in terms of summer nutrient depletion.

  20. Nocturnal Fish Use of New Jersey Marsh Creek and Adjacent Bay Shoal Habitats

    NASA Astrophysics Data System (ADS)

    Rountree, R. A.; Able, K. W.

    1997-06-01

    Night-time sampling with gill nets in the Little Egg Harbor estuary revealed a component of the estuarine fish fauna, hitherto poorly documented, which is comprised of relatively large size classes of juvenile and adult life history stages. The fishesMustelus canis, Pomatomus saltatrix, Paralichthys dentatus, Brevoortia tyrannus, Prionotus evolansandAlosa mediocriswere the most abundant fishes captured. These observations suggest that Mid-Atlantic Bight estuaries are important nurseries for juvenile stages beyond the first year, as well as for the young of the year (YOY). Although many other studies emphasise the importance of estuaries as nurseries for YOY stages, the importance of estuaries to later juvenile life stages has been largely overlooked. This component of estuarine fish fauna has been poorly represented in previous North American studies because of probable gear avoidance, and because most studies are conducted primarily during the day. The authors hypothesise that these later juvenile stages are likely to be important estuarine faunal components in other geographic regions, as well as in the Mid-Atlantic Bight. A descriptive comparison of catches between ebb and flood tide stages, and between bay shoal and tidal marsh creek habitats, suggests that later juvenile and adult stages of several species make tidal migrations into shallow estuarine habitats, such as shoals and marsh creeks, during the night hours.

  1. Comparative ecology of H2 cycling in sedimentary and phototrophic ecosystems

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; Albert, Daniel B.; Alperin, Marc J.; Bebout, Brad M.; Martens, Christopher S.; Des Marais, David J.

    2002-01-01

    The simple biochemistry of H2 is critical to a large number of microbial processes, affecting the interaction of organisms with each other and with the environment. The sensitivity of each of these processes to H2 can be described collectively, through the quantitative language of thermodynamics. A necessary prerequisite is to understand the factors that, in turn, control H2 partial pressures. These factors are assessed for two distinctly different ecosystems. In anoxic sediments from Cape Lookout Bight (North Carolina, USA), H2 partial pressures are strictly maintained at low, steady-state levels by H2-consuming organisms, in a fashion that can be quantitatively predicted by simple thermodynamic calculations. In phototrophic microbial mats from Baja California (Mexico), H2 partial pressures are controlled by the activity of light-sensitive H2-producing organisms, and consequently fluctuate over orders of magnitude on a daily basis. The differences in H2 cycling can subsequently impact any of the H2-sensitive microbial processes in these systems. In one example, methanogenesis in Cape Lookout Bight sediments is completely suppressed through the efficient consumption of H2 by sulfate-reducing bacteria; in contrast, elevated levels of H2 prevail in the producer-controlled phototrophic system, and methanogenesis occurs readily in the presence of 40 mM sulfate.

  2. Interdisciplinary approach to the demography of Jamaica

    PubMed Central

    2012-01-01

    Background The trans-Atlantic slave trade dramatically changed the demographic makeup of the New World, with varying regions of the African coast exploited differently over roughly a 400 year period. When compared to the discrete mitochondrial haplotype distribution of historically appropriate source populations, the unique distribution within a specific source population can prove insightful in estimating the contribution of each population. Here, we analyzed the first hypervariable region of mitochondrial DNA in a sample from the Caribbean island of Jamaica and compared it to aggregated populations in Africa divided according to historiographically defined segments of the continent's coastline. The results from these admixture procedures were then compared to the wealth of historic knowledge surrounding the disembarkation of Africans on the island. Results In line with previous findings, the matriline of Jamaica is almost entirely of West African descent. Results from the admixture analyses suggest modern Jamaicans share a closer affinity with groups from the Gold Coast and Bight of Benin despite high mortality, low fecundity, and waning regional importation. The slaves from the Bight of Biafra and West-central Africa were imported in great numbers; however, the results suggest a deficit in expected maternal contribution from those regions. Conclusions When considering the demographic pressures imposed by chattel slavery on Jamaica during the slave era, the results seem incongruous. Ethnolinguistic and ethnographic evidence, however, may explain the apparent non-random levels of genetic perseverance. The application of genetics may prove useful in answering difficult demographic questions left by historically voiceless groups. PMID:22360861

  3. Fluorescence of dissolved organic matter: A comparison of north Pacific and north Atlantic Oceans during April 1991

    NASA Technical Reports Server (NTRS)

    Hoge, Frank E.; Swift, Robert N.; Yungel, James K.; Vodacek, Anthony

    1993-01-01

    Profiles of airborne-laser-induced fluorescence emission from dissolved organic matter in the upper ocean have been produced and compared for the Southern California Bight (SCB) and the Mid-Atlantic Bight (MAB). Findings were as follows. (1) The fluorescent components of dissolved organic matter (FDOM) are present in easily measurable quantities from near shore to well over 300 km offshore in the SCB and are likewise easily measurable in the coastal, shelf, slope, and Gulf Stream waters of the MAB. (2) The reange of FDOM in the MAB is considerably greater than that in the SCB. (3) The lowest FDOM levels observed in the SCB were higher than those found in the Gulf Stream. (4) The onshore-to-offshore spatial gradient of the FDOM was found to be considerably lower in the SCB than in the MAB, with the highest levels of FDOM being found immediately adjacent to the coast in the MAB. This suggests that the water adjacent to the SCB shoreline is not as strongly influenced by terrestrial and estuarine sources of FDOM as the MAB is. (5) The spatial distribution of the FDOM within both the SCB and the MAB is frequently coherent with the spatial distribution of chlorophyll determined form the concurrent airborne- laser- induced phytoplankton pigment fluorescence measurements. However, distinct noncoherency is sometimes observed, especially at water mass boundaries.

  4. Freshly Emitted, Unexpectedly High SO2, SO4=, NOx, CH4, and i-C4H10 Offshore of Los Angeles Attributed to Several Source Sectors

    NASA Astrophysics Data System (ADS)

    Chatfield, R. B.; Blake, D. R.; Crounse, J.; Diskin, G. S.; Esswein, R.; Nenes, A.; Singh, H. B.; Weinheimer, A. J.; Wisthaler, A.

    2013-12-01

    The NASA DC-8 made repeated flights over Los Angeles and the Southern California Bight, revealing very intermittent spikes of sulfur dioxide, sulfate, reactive nitrogen oxides, toluene, i-butane methane and black carbon. There was some coherence between spikes of these compounds, but often they were distinct. These samples were taken in the California portion of the ARCTAS sampling intensive (Cal-ARCTAS); the large compliment of simultaneous measurements on the DC-8 allow us to highlight or downplay source sectors. We will help confirm attributions using with local trajectory calculations. The NASA flights in 2008 went much further west than NOAA's CalNEX flights in 2010, and measurements reflecting these sources seem to be only occasionally apparent in published analyses of CalNEX. These analyses suggested that Los Angeles source inventories and observations were in good agreement. From the location of sampling and correlations, we surmise important sources included natural hydrocarbon seeps, petroleum production as well as shipping and perhaps aircraft emissions. These sources, often upwind of the South Coast cities, may be variable and may add to known emission databases. (Left) Influence of petroleum-associated emissions in the Southern California Bight. iso-Butane i excess over the traffic-associated butanes, indicating natural petroleum origin. (Right) SO2 (Georgia Tech) in a similar plot. Largest concentrations in South Coast area are offshore.

  5. Dynamics of the Cold Water Event off the Southeast Coast of the United States in the Summer of 2003: An Application of NASA's Remote Sensing Data to Coastal Studies

    NASA Technical Reports Server (NTRS)

    Yuan, Dongliang; Savtchenko, Andrey; Li, Chunyan,

    2004-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard of Terra and Aqua satellites provide, for the first time, concurrent measurements of sea surface temperature (SST) and ocean color, which are suitable for coastal upwelling studies. The accuracy, the 1-km spatial resolution, and the almost complete daily coverage of the MODIS data compared with historical measurements make it advantageous for resolving important coastal fronts of chlorophyll concentration and temperature. The cold SST anomaly during summer 2003 off the coast of the South Atlantic Bight is an event that is comprehensively covered by NASA's MODIS and SeaWinds satellite observations. These data combined with in situ tide gauge, mooring, and ship measurements can be used to identify important dynamics responsible for the anomalous cold water event. The analysis of the data suggests that coastal upwelling occurs in the climatological summer forced by the climatological southerlies over the South Atlantic Bight area in summer. However, the strong buoyancy barrier in summer prevents the cold water below the thermocline from reaching the ocean surface. In summer 2003, the southwesterlies in July through August were extraordinarily strong and persistent, which generated the upwelling currents strong enough to overcome the buoyancy resistance. The results of this analysis demonstrate the possibility of monitoring and forecasting the event using combination of the satellite and in situ observations. The MODIS data are archived and distributed by the NASA's Goddard Earth Science (GES) Distributed Active Archive Center (DAAC). The data can be accessed via the URL http://wwv.daac.gsfc.nasa.gov/MODIS.

  6. Chromophoric dissolved organic matter export from U.S. rivers

    USGS Publications Warehouse

    Spencer, Robert G. M.; Aiken, George R.; Dornblaser, Mark M.; Butler, Kenna D.; Holmes, R. Max; Fiske, Greg; Mann, Paul J.; Stubbins, Aron

    2013-01-01

    Chromophoric dissolved organic matter (CDOM) fluxes and yields from 15 major U.S. rivers draining an assortment of terrestrial biomes are presented. A robust relationship between CDOM and dissolved organic carbon (DOC) loads is established (e.g., a350 versus DOC; r2 = 0.96, p < 0.001). Calculated CDOM yields are also correlated to watershed percent wetland (e.g. a350; r2 = 0.81, p < 0.001) providing a method for the estimation of CDOM export from ungauged watersheds. A large variation in CDOM yields was found across the rivers. The two rivers in the north-eastern U.S. (Androscoggin and Penobscot), the Edisto draining into the South Atlantic Bight, and some rivers draining into the Gulf of Mexico (Atchafalaya and Mobile) exhibit the highest CDOM yields, linked to extensive wetlands in these watersheds. If the Edisto CDOM yield is representative of other rivers draining into the South Atlantic Bight, this would result in a CDOM load equivalent to that of the Mississippi from a region of approximately 10% of the Mississippi watershed, indicating the importance of certain regions with respect to the role of terrigenous CDOM in ocean color budgets.

  7. Distinct zooplankton regime shift patterns across ecoregions of the U.S. Northeast continental shelf Large Marine Ecosystem

    NASA Astrophysics Data System (ADS)

    Morse, R. E.; Friedland, K. D.; Tommasi, D.; Stock, C.; Nye, J.

    2017-01-01

    We investigated regime shifts in seasonal zooplankton communities of the Northeast continental shelf Large Marine Ecosystem (NES) and its subcomponent ecoregions over a multi-decadal period (1977-2013). Our cross ecoregion analysis shows that regime shifts in different ecoregions often exhibited very distinct characteristics, emphasizing more granular fluctuations in NES plankton communities relative to previous work. Shifts early in the time series generally reflected an increase in abundance levels. The response of zooplankton abundance within fall communities was more similar among ecoregions than for spring communities. The Gulf of Maine exhibited highly distinct patterns from other ecoregions, with regime shifts identified in the early 1980s, early 2000s, and mid-2000s for spring communities. Regime shifts were identified in the early to mid-1990s for the NES, Georges Bank, and the Mid-Atlantic Bight ecoregions, while the fall communities experienced shifts in the early 1990s and late 1980s for the NES and Georges Bank, but in the late 1990s in the Mid-Atlantic Bight. A constrained correspondence analysis of zooplankton community against local and basin-scale climatological indices suggests that water temperature, stratification, and the Atlantic multidecadal oscillation (AMO) were the predominant factors in driving the zooplankton community composition.

  8. Decadal Declines of Mercury in Adult Bluefish (1972-2011) from the Mid-Atlantic Coast of the U.S.A.

    PubMed

    Cross, Ford A; Evans, David W; Barber, Richard T

    2015-08-04

    Concentrations of total mercury were measured in muscle of adult bluefish (Pomatomus saltatrix) collected in 2011 off North Carolina and compared with similar measurements made in 1972. Concentrations of mercury decreased by 43% in the fish between the two time periods, with an average rate of decline of about 10% per decade. This reduction is similar to estimated reductions of mercury observed in atmospheric deposition, riverine input, seawater, freshwater lakes, and freshwater fish across northern North America. Eight other studies between 1973 and 2007 confirm the decrease in mercury levels in bluefish captured in the Mid-Atlantic Bight. These findings imply that (1) reductions in the release of mercury across northern North America were reflected rather quickly (decades) in the decline of mercury in adult bluefish; (2) marine predatory fish may have been contaminated by anthropogenic sources of mercury for over 100 years; and (3) if bluefish are surrogates for other predators in the Mid-Atlantic Bight, then a reduction in the intake of mercury by the fish-consuming public has occurred. Finally, with global emissions of mercury continuing to increase, especially from Asia, it is important that long-term monitoring programs be conducted for mercury in marine fish of economic importance.

  9. Investigation of Climate Change Impacts to the Coastal Aquifer of North Germany: A 3D Modelling Study

    NASA Astrophysics Data System (ADS)

    Ptak, T.; Yang, J.; Graf, T.

    2014-12-01

    Climate change is expected to induce sea level rise in the German Bight, which is part of the North Sea, Germany. Climate change may also modify discharge of the river Weser flowing into the German Bight, which will alter both water levels and salinity distributions along the coast. To study the long-term effects of sea level rise and discharge variations to the salinity distribution, a 3D seawater intrusion model was designed using the fully coupled surface-subsurface numerical model HydroGeoSphere. The model simulates the coastal aquifer as an integral system considering complexities such as variable-density groundwater flow, surface-subsurface interaction, irregular land topography and anthropogenic structures (e.g. dykes, drainage canals, water gates). Using PEST, steady state groundwater flow of year 2009 is calibrated. In addition, 3 climate change scenarios are simulated based on the calibrated model: (i) sea level rise of 1 m, (ii) the salinity of the seaside boundary increased by 25 %, and (iii) the salinity of the seaside boundary decreased by 70 %. Results demonstrate the changes of fresh groundwater resources, surface water depths and salinity distribution. The obtained results are useful for coastal engineering practices, drinking water resources management and for the development of climate change adaptation strategies.

  10. Fish embryos: Practical indicators of environmental quality of significance to fisheries

    SciTech Connect

    Longwell, A.C. )

    1988-10-01

    Cyto-embryological analyses of fish eggs collected in nature can be a more sensitive indicator of environmental pollution than more typical assays conducted on artificially-spawned eggs. This is because uncertainties associated with artificial spawning and rearing are dispensed with, as well as because of the sensitivity of some cellular and subcellular analyses. At the same time, such measures can provide information on interannual differences in egg viability of importance in elucidating great, unexplained variability in fisheries recruitment. Extensive experience with fish embryos from ocean plankton has led to the choice of a particularly useful, practical suite of observations for different developmental stages. This includes measures of embryo mortality, mutagenicity, teratogenicity, abnormal cell differentiation, and development rate. Atlantic mackerel egg mortality has been determined to be greater in the surface waters of the New York Bight apex and along the New Jersey coast than in less polluted portions of the Bight. Chromosome abnormality of mid-stage embryos was also greater in more impacted areas of the same water mass, as well as in the somatic cells of adult mackerel and winter flounder, and in juvenile and adult windowpane flounder caught in more impacted areas. Mortality and abnormality of the mackerel embryos showed statistical associations with toxic hydrocarbons as measured in plankton, and with heavy metals as measured in sea surface waters. The sensitivity, practicality, and relevance of the cytoembryological studies to population dynamics of resource species make this an important means of monitoring environmental quality.

  11. Trace metal fluxes to ferromanganese nodules from the western Baltic Sea as a record for long-term environmental changes

    SciTech Connect

    Hlawatsch, S.; Garbe-Schonberg, C.D.; Lechtenberg, F.; Manceau, A.; Tamura, N.; Kulik, D.A.; Suess, E.; Kersten, M.

    2002-03-12

    Trace element profiles in ferromanganese nodules from the western Baltic Sea were analyzed with laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) and synchrotron-based micro-X-ray radiation techniques (fluorescence: mSXRF, and diffraction: mXRD) at high spatial resolution in growth direction. Of the trace elements studied (Zn, Cu, Cd, Ni, Co, Mo, Ba), Zn showed the most significant enrichment, with values in the outermost surface layers of up to six-fold higher than those found in older core parts. The high-resolution Zn profiles provide the necessary temporal resolution for a dating method analogous to dendrochronology. Profiles in various samples collected during two decades were matched and the overlapping sections used for estimation of the accretion rates. Assuming a continuous accretion of these relatively fast growing nodules (on average 20 mm a-1) over the last century, the Zn enrichment was thus assessed to have commenced around 1860/70 in nodules from the Kiel Bight and in 1880/90 from Mecklenburg Bight, reflecting the enhanced heavy metal emissions with rising industrialization in Europe. Apart from the obvious success with Zn, only As and Co show significant but only 1.5-fold enrichments in the most recent growth layers of the nodules. Other anthropogenic trace metals like Cu and Cd are not at all enriched, which, together with the distinct early-diagenetic Fe/Mn banding, weakens the potential of the nodules for retrospective monitoring.

  12. Meteo-marine parameters for highly variable environment in coastal regions from satellite radar images

    NASA Astrophysics Data System (ADS)

    Pleskachevsky, A. L.; Rosenthal, W.; Lehner, S.

    2016-09-01

    The German Bight of the North Sea is the area with highly variable sea state conditions, intensive ship traffic and with a high density of offshore installations, e.g. wind farms in use and under construction. Ship navigation and the docking on offshore constructions is impeded by significant wave heights HS > 1.3 m. For these reasons, improvements are required in recognition and forecasting of sea state HS in the range 0-3 m. Thus, this necessitates the development of new methods to determine the distribution of meteo-marine parameters from remote sensing data with an accuracy of decimetres for HS. The operationalization of these methods then allows the robust automatic processing in near real time (NRT) to support forecast agencies by providing validations for model results. A new empirical algorithm XWAVE_C (C = coastal) for estimation of significant wave height from X-band satellite-borne Synthetic Aperture Radar (SAR) data has been developed, adopted for coastal applications using TerraSAR-X (TS-X) and Tandem-X (TD-X) satellites in the German Bight and implemented into the Sea Sate Processor (SSP) for fully automatic processing for NRT services. The algorithm is based on the spectral analysis of subscenes and the model function uses integrated image spectra parameters as well as local wind information from the analyzed subscene. The algorithm is able to recognize and remove the influence of non-sea state produced signals in the Wadden Sea areas such as dry sandbars as well as nonlinear SAR image distortions produced by e.g. short wind waves and breaking waves. Also parameters of very short waves, which are not visible in SAR images and produce only unsystematic clutter, can be accurately estimated. The SSP includes XWAVE_C, a pre-filtering procedure for removing artefacts such as ships, seamarks, buoys, offshore constructions and slicks, and an additional procedure performing a check of results based on the statistics of the whole scene. The SSP allows an

  13. The Colombia Current: An Eastern Tropical Pacific Coastal Current, Early Oceanographic Characteristics

    NASA Astrophysics Data System (ADS)

    Rodriguez-Rubio, E.

    2007-05-01

    Newly gathered hydrographic data from the Colombia Pacific Ocean is combined with remote sensing data to reassess the properties of the costal current named Colombian Current by Wooster (1959). The Colombian Pacific Ocean is located between 84°-76°W and 1°30'-5°N (oceanic zone), 1°30'- 7°N (coastal zone): This area is well-known also like Panama Bight. New hydrographic data were occupied along the Colombian Pacific coast during March of 2006, making 41 stations with measurements of CTD until a maximum depth of 1200 m, depending on the depth of the marine bottom. On the other hand, sea surface temperatures (SST) were obtained from the MODIS-AQUA satellite and sea surface wind speed and wind direction stem from QuickScat, both averaged for March 2006. Hydrographic grid layers necessary to obtain dynamic topography variable were made with objective mapping calculating is not total dynamic height, but the dynamic height between consecutive levels or "thickness". The purpose of this methodology is that in very coastal campaigns it can have a substantial number of stations that do not arrive at the reference level. Finally geostrophic velocity was computed for the Colombian Current area at several layers. The coast was characterized by low salinities due to river runoff in the North zone. The sea surface temperature during the month of March of 2006 was especially low in the oceanic zone, reaching temperatures between 19°C and 24°C.The dynamic topography indicated the presence of a surface coastal current flowing towards the north and a crosscurrent to 400 m of depth never before described. The wind corresponded to the pattern of the wind jet of Panama. During March the ITCZ moves south, drawing the Panama jet across the Isthmus and over the Pacific. Upwelling curl associated with the left (southeast) flank of this jet generates a cyclonic eddy in the Panama Bight and SST cooling in its center. In the Panama Bight, the curl dipole produces a cyclonic circulation

  14. Photographs of the Sea floor Offshore of New York and New Jersey

    USGS Publications Warehouse

    Butman, Bradford; Gutierrez, Benjamin T.; ten Brink, Marilyn Buchholtz; Schwab, William S.; Blackwood, Dann S.; Mecray, Ellen L.; Middleton, Tammie J.

    2003-01-01

    This DVD-ROM contains photographs of the sea floor and sediment texture data collected as part of studies carried out by the U.S. Geological Survey (USGS) in the New York Bight (Figure 1a (PDF format)). The studies were designed to map the sea floor (Butman, 1998, URL: http://pubs.usgs.gov/fs/fs133-98/) and to develop an understanding of the transport and long-term fate of sediments and associated contaminants in the region (Mecray and others, 1999, URL: http://pubs.usgs.gov/fs/fs114-99/). The data were collected on four research cruises carried out between 1996 and 2000 (Appendix I). The images and texture data were collected to provide direct observations of the sea floor geology and to aid in the interpretation of backscatter intensity data obtained from sidescan sonar and multibeam surveys of the sea floor. Preliminary descriptions of the sea floor geology in this region may be found in Schwab and others (2000, URL: http://pubs.usgs.gov/of/of00-295/; 2003), Butman and others (1998, URL: http://pubs.usgs.gov/of/of98-616/.), and Butman and others (2002, URL: http://pubs.usgs.gov/of/of00-503/). Schwab and others (2000 URL: http://pubs.usgs.gov/of/of00-295/; 2003) have identified 11 geologic units in New York Bight (Figure 2 (PDF format)). These units identify areas of active sediment transport, extensive anthropogenic influence on the sea floor, and various geologic units. Butman and others (2003) and Harris and others (in press) present the results of a moored array experiment carried out in the Hudson Shelf Valley to investigate the transport of sediments during winter. Summaries of these and other studies may be found at USGS studies in the New York Bight (URL: http://woodshole.er.usgs.gov/project-pages/newyork/). This DVD-ROM contains digital images of bottom still photographs, images digitized from videos, sediment grain-size analysis results, and short QuickTime movies from video transects. The data are presented in tabular form and in an ESRI (Environmental

  15. Polyfluorinated compounds in ambient air from ship- and land-based measurements in northern Germany

    NASA Astrophysics Data System (ADS)

    Dreyer, Annekatrin; Ebinghaus, Ralf

    Neutral volatile and semi-volatile polyfluorinated organic compounds (PFC) and ionic perfluorinated compounds were determined in air samples collected at two sites in the vicinity of Hamburg, Germany, and onboard the German research vessel Atair during a cruise in the German Bight, North Sea, in early November 2007. PUF/XAD-2/PUF cartridges and glass fiber filters as sampling media were applied to collect several fluorotelomer alcohols (FTOH), fluorotelomer acrylates (FTA), perfluoroalkyl sulfonamides (FASA), and perfluoroalkyl sulfonamido ethanols (FASE) in the gas- and particle-phase as well as a set of perfluorinated carboxylates (PFCA) and sulfonates (PFSA) in the particle-phase. This study presents the distribution of PFC in ambient air of the German North Sea and in the vicinity of Hamburg for the first time. Average total PFC concentrations in and around Hamburg (180 pg m -3) were higher than those observed in the German Bight (80 pg m -3). In the German Bight, minimum-maximum gas-phase concentrations of 17-82 pg m -3 for ΣFTOH, 2.6-10 pg m -3 for ΣFTA, 10-15 pg m -3 for ΣFASA, and 2-4.4 pg m -3 for ΣFASE were determined. In the vicinity of Hamburg, minimum-maximum gas-phase concentrations of 32-204 pg m -3 for ΣFTOH, 3-26 pg m -3 for ΣFTA, 3-18 pg m -3 for ΣFASA, and 2-15 pg m -3 for ΣFASE were detected. Concentrations of perfluorinated acids were in the range of 1-11 pg m -3. FTOH clearly dominated the substance spectrum; 8:2 FTOH occurred in maximum proportions. Air mass back trajectories, cluster, and correlation analyses revealed that the air mass origin and thus medium to long range atmospheric transport was the governing parameter for the amount of PFC in ambient air. Southwesterly located source regions seemed to be responsible for elevated PFC concentrations, local sources appeared to be of minor importance.

  16. Increased winds in California's Channel Islands; Evaluation of trends in reanalysis model back-casts over the last half century with implications for human impacts

    NASA Astrophysics Data System (ADS)

    Katz, S. L.

    2011-12-01

    As elsewhere, in the Southern California Bight (SCB) the role of coastal winds in driving local ocean circulation has lead to extensive research on the character of the atmospheric boundary layer, and the recognition that wind stress and curl have increased in the recent past. However, around Northern Channel Islands in the SCB, local mariners have claimed that recently conditions have gotten perceptibly windier. The general pattern of winds in this area include strong equartorward flow along the central California coast outside the SCB and discretely weaker flow in the inner SCB with a pronounced transition south and east of Point Conception. Increased surface winds have numerous implications for local commerce and maritime safety, including limitations on days at sea by fishermen, tourists and commercial traffic. However, human perception of environmental conditions are often biased by perceptions of extreme events as representative of larger scale or longer term conditions. To evaluate if recent perceptions are accurate, we evaluated trends in surface winds generated by NCAR/NCEP and European Center for Medium Range Weather Forecasts (ECMWF) reanalysis models. Reanalysis back-casts revealed that indeed surface winds in the areas of the outer Southern California Bight are increasingly windy on average, and that averages are increasing due to increasing frequency of wind events, rather than the entire distribution of winds shifting to higher speeds. In some localized areas the number of days within a year that exceed 20knots (10.31 m/s) on average are increasing at a rate of one additional day per year in the NCAR/NCEP data. The utility of 20knots is this is wind speed that can trigger a small craft warning from the US Coast Guard, and which will in turn affect human activity on the sea. The spatial distribution of the increasing trends indicates that there is a focus of increasing winds to the South of Point Conception and North West of San Nicolas Island within

  17. Detecting toxic diatom blooms from ocean color and a regional ocean model

    NASA Astrophysics Data System (ADS)

    Anderson, Clarissa R.; Kudela, Raphael M.; Benitez-Nelson, Claudia; Sekula-Wood, Emily; Burrell, Christopher T.; Chao, Yi; Langlois, Gregg; Goodman, Jo; Siegel, David A.

    2011-02-01

    An apparent link between upwelling-related physical signatures, macronutrients, and toxic diatom blooms in the various “hotspots” throughout California has motivated attempts to forecast harmful algal blooms (HABs) as a function of select environmental variables. Empirical models for predicting toxic Pseudo-nitzschia blooms in one such region, the Santa Barbara Channel (SBC), are tested in a nowcast mode using predictions based on merging data from MODIS ocean color geophysical products and the Regional Ocean Modeling System (ROMS) applied to the Southern California Bight. Thresholds for each model generate event forecasts. Spatially-explicit, monthly HAB maps are compared to shipboard observations and California monitoring data, demonstrating that the models predict offshore events otherwise undetected by nearshore monitoring. The use of mechanistic hydrodynamic models in concert with empirical, biological models facilitates future process studies on the effects of coastal eutrophication and climate change on regional HAB dynamics.

  18. Shelf export of particulates/transport in continental margin waters. Final report

    SciTech Connect

    Pietrafesa, L.J.

    1995-07-01

    During the present funding period, research activities at NCSU have been directed towards: publishing the results of SEEP-I; publishing further results from NCSU`s South Atlantic Bight studies; designing and constructing four cages which house the 3 NCSU and 1 BNL RD-Acoustic Doppler Current Profilers used successfully in SEEP-II, calibrating all current meters, transmissometers, thermister chains and conductivity pressure and temperature sensors for SEEP-II phases 2 and 3; determining the temporal and spatial scales of physical processes observed during phase 1 of SEEP-II in preparation for finalizing the mooring positions and sampling intervals for SEEP-II; shipping all NCSU gear to the URI and ODU; and successful deployment of NCSU SEEP-II, phases 1 and 2 moorings.

  19. Where the offshore search for oil and gas is headed

    SciTech Connect

    King, R.E.

    1980-10-01

    This overview of the world's potential offshore oil and gas frontiers points out that although solutions to technical and political problems have opened up some promising areas for exploration, many key frontier basins have yet to be explored by modern technology. Long-standing disputes between bordering countries over offshore rights have deterred exploration activities in the Malvinas basin off Argentina and in the Gulf of Venezuela. Political problems have also slowed activity in the US Atlantic offshore, where Mesozoic reef trends may be related to Mexico's large oil fields. In Canada's Labrador Sea and Grand Banks, the problems are largely operational because of the inclement weather and threatening icebergs. The thick sediments off northern Norway remain untapped due to the deep water, Arctic conditions, and boundary disputes with the USSR. The main areas of active exploration are the Gulf of Thailand-Penyu-Natuna basin in Southeast Asia and Ireland's Porcupine Bight basin.

  20. Differential recruitment of bivalve species in the northern Wadden Sea after the severe winter of 1995/96 and of subsequent milder winters

    NASA Astrophysics Data System (ADS)

    Strasser, Matthias; Hertlein, Andrea; Reise, Karsten

    2001-08-01

    High recruitment of the bivalves Cerastoderma edule, Mytilus edulis, Macoma balthica and Mya arenaria in summer after severe winters is an often reported phenomenon in the Wadden Sea. After the severe winter of 1995/96 however, only Cerastoderma and Mytilus followed this pattern in the Sylt-Rømø Bight. Repeated sampling of Cerastoderma, Macoma and Mya following a severe (1995/96), a moderate (1996/97), and a mild winter (1997/98) revealed that early recruitment was highest after the mild winter. In Cerastoderma the eventual high recruitment at the end of summer 1996 was caused by reduced benthic mortality. Low recruitment of Macoma and Mya after the severe winter may have been caused by a higher susceptibility to epibenthic predation and/or a higher susceptibility to passive re-suspension than in Cerastoderma and Mytilus. In all cases, post-settlement processes were decisive for reproductive success.

  1. Confidence rating for eutrophication assessments.

    PubMed

    Brockmann, Uwe H; Topcu, Dilek H

    2014-05-15

    Confidence of monitoring data is dependent on their variability and representativeness of sampling in space and time. Whereas variability can be assessed as statistical confidence limits, representative sampling is related to equidistant sampling, considering gradients or changing rates at sampling gaps. By the proposed method both aspects are combined, resulting in balanced results for examples of total nitrogen concentrations in the German Bight/North Sea. For assessing sampling representativeness surface areas, vertical profiles and time periods are divided into regular sections for which individually the representativeness is calculated. The sums correspond to the overall representativeness of sampling in the defined area/time period. Effects of not sampled sections are estimated along parallel rows by reducing their confidence, considering their distances to next sampled sections and the interrupted gradients/changing rates. Confidence rating of time sections is based on maximum differences of sampling rates at regular time steps and related means of concentrations.

  2. On the recent destabilization of the Gulf Stream path downstream of Cape Hatteras

    NASA Astrophysics Data System (ADS)

    Andres, M.

    2016-09-01

    Mapped satellite altimetry reveals interannual variability in the position of initiation of Gulf Stream meanders downstream of Cape Hatteras. The longitude where the Gulf Stream begins meandering varies by 1500 km. There has been a general trend for the destabilization point to shift west, and 5 of the last 6 years had a Gulf Stream destabilization point upstream of the New England Seamounts. Independent in situ data suggest that this shift has increased both upper-ocean/deep-ocean interaction events at Line W and open-ocean/shelf interactions across the Middle Atlantic Bight (MAB) shelf break. Mooring data and along-track altimetry indicate a recent increase in the number of deep cyclones that stir Deep Western Boundary Current waters from the MAB slope into the deep interior. Temperature profiles from the Oleander Program suggest that recent enhanced warming of the MAB shelf may be related to shifts in the Gulf Stream's destabilization point.

  3. Long-term changes in Prosobranchia (Gastropoda) abundances on the German North Sea coast: the role of the anti-fouling biocide tributyltin

    NASA Astrophysics Data System (ADS)

    Nehring, S.

    2000-05-01

    Tributyltin (TBT) has been used as a biocide in marine anti-fouling paints since the early 1970s. Due to its strong ecotoxicity and the relatively high levels in the water column as well as in port sediments on the German North Sea coast, it probably has negative ecological effects on organisms other than those targeted. An analysis of the long-term development of prosobranch stocks in the inner German Bight reveals a decrease in abundance of many species. For most species the decline cannot be attributed to TBT, but in four prosobranch species ( Buccinum undatum, Hydrobia ulvae, Littorina littorea and Nucella lapillus) significant ecological effects by TBT pollution are very probable. Although research for alternative non-TBT anti-fouling paints (e.g. biocide-free types on the basis of silicone) has been intensified, the potential threats to ecosystems and the ecotoxicological profiles of these alternatives have to be carefully evaluated.

  4. Southeastern U.S.A. Continental Shelf Respiratory Rates Revisited

    NASA Technical Reports Server (NTRS)

    Sheldon, Joan E.; Griffith, Peter C.; Peters Francesc; Sheldon, Wade M., Jr.; Blanton, Jackson O.; Amft, Julie; Pomeroy, Lawrence R.

    2010-01-01

    Respiratory rates on the U. S. southeastern continental shelf have been estimated several times by different investigators, most recently by Jiang et al. (Biogeochemistry 98:101-113, 2010) who report lower mean rates thanwere found in earlier work and attribute the differences to analytical error in all methods used in earlier studies. The differences are, instead, attributable to the differences in the geographical scope of the studies. The lower estimates of regional organic carbon flux of Jiang et al. (Biogeochemistry 98:101-113, 2010) are a consequence of their extrapolation of data from a small portion of the shelf to the entire South Atlantic Bight. This comment examines the methodologies used as well as the variability of respiratory rates in this region over space and time.

  5. Mussel Watch update: long-term trends in selected contaminants from coastal California, 1977-2010.

    PubMed

    Melwani, Aroon R; Gregorio, Dominic; Jin, Yujie; Stephenson, Mark; Ichikawa, Gary; Siegel, Emily; Crane, Dave; Lauenstein, Gunnar; Davis, Jay A

    2014-04-30

    This study examined trends in contaminants measured during three decades of "Mussel Watch" monitoring on the California coast. Chlorinated organic contaminants and butyltins declined the most rapidly, with tissue concentrations in 2010 that were up to 75% lower than during the 1980s. Silver and lead declined at about half of the stations statewide, but generally exhibited slower rates of decline relative to the organic compounds. In contrast, copper increased at many stations, and PAHs showed little evidence for declines. Mussels from San Francisco Bay and the Southern California Bight were historically the most contaminated and have had the steepest declines. Overall, these data show that the "Mussel Watch" approach to monitoring contaminants in California has provided some of the best evidence of the effectiveness of actions to improve water quality over the past 30 years. These datasets also highlight challenges that remain in managing PAHs and copper.

  6. Oceanography of the Southeastern Continental Shelf

    NASA Astrophysics Data System (ADS)

    This volume, the second in the Coastal and Estuarine Sciences series, provides a synthesis of the physical, chemical, and biological oceanography of the South Atlantic Bight (SAB). The results presented derive from a decade-long multidisciplinary investigation of the SAB continental shelf regime.The SAB extends from West Palm Beach, Fla., where the narrow south Florida shelf begins to broaden, to Cape Hatteras, N.C., where the shelf again narrows. This broad and shallow area is distinguished by the proximity of the Gulf Stream to the shelf break. Large contrasts in the distribution of properties, the strength of oceanic and atmospheric forces, and the high frequency (4-12 days) at which these forces vary have created a unique natural laboratory in which a variety of oceanic processes may be studied.

  7. Coastal pollution hazards in southern California observed by SAR imagery: stormwater plumes, wastewater plumes, and natural hydrocarbon seeps

    NASA Technical Reports Server (NTRS)

    Digiacomo, Paul M.; Washburn, Libe; Holt, Benjamin; Jones, Burton H.

    2004-01-01

    Stormwater runoff plumes, municipal wastewater plumes, and natural hydrocarbon seeps are important pollution hazards for the heavily populated Southern California Bight (SCB). Due to their small size, dynamic and episodic nature, these hazards are difficult to sample adequately using traditional in situ oceanographic methods. Complex coastal circulation and persistent cloud cover can further complicate detection and monitoring of these hazards. We use imagery from space-borne synthetic aperture radar (SAR), complemented by field measurements, to examine these hazards in the SCB. The hazards are detectable in SAR imagery because they deposit surfactants on the sea surface, smoothing capillary and small gravity waves to produce areas of reduced backscatter compared with the surrounding ocean. We suggest that high-resolution SAR, which obtains useful data regardless of darkness or cloud cover, could be an important observational tool for assessment and monitoring of coastal marine pollution hazards in the SCB and other urbanized coastal regions.

  8. Effects of chemical dispersants on oil spill drift paths in the German Bight—probabilistic assessment based on numerical ensemble simulations

    NASA Astrophysics Data System (ADS)

    Schwichtenberg, Fabian; Callies, Ulrich; Groll, Nikolaus; Maßmann, Silvia

    2016-06-01

    Oil dispersed in the water column remains sheltered from wind forcing, so that an altered drift path is a key consequence of using chemical dispersants. In this study, ensemble simulations were conducted based on 7 years of simulated atmospheric and marine conditions, evaluating 2,190 hypothetical spills from each of 636 cells of a regular grid covering the inner German Bight (SE North Sea). Each simulation compares two idealized setups assuming either undispersed or fully dispersed oil. Differences are summarized in a spatial map of probabilities that chemical dispersant applications would help prevent oil pollution from entering intertidal coastal areas of the Wadden Sea. High probabilities of success overlap strongly with coastal regions between 10 m and 20 m water depth, where the use of chemical dispersants for oil spill response is a particularly contentious topic. The present study prepares the ground for a more detailed net environmental benefit analysis (NEBA) accounting also for toxic effects.

  9. Potential on-shore and off-shore reservoirs for CO2 sequestration in Central Atlantic magmatic province basalts

    PubMed Central

    Goldberg, David S.; Kent, Dennis V.; Olsen, Paul E.

    2010-01-01

    Identifying locations for secure sequestration of CO2 in geological formations is one of our most pressing global scientific problems. Injection into basalt formations provides unique and significant advantages over other potential geological storage options, including large potential storage volumes and permanent fixation of carbon by mineralization. The Central Atlantic Magmatic Province basalt flows along the eastern seaboard of the United States may provide large and secure storage reservoirs both onshore and offshore. Sites in the South Georgia basin, the New York Bight basin, and the Sandy Hook basin offer promising basalt-hosted reservoirs with considerable potential for CO2 sequestration due to their proximity to major metropolitan centers, and thus to large industrial sources for CO2. Onshore sites are suggested for cost-effective characterization studies of these reservoirs, although offshore sites may offer larger potential capacity and additional long-term advantages for safe and secure CO2 sequestration. PMID:20080705

  10. Mathematical model investigation of long-term transport of ocean-dumped sewage sludge related to remote sensing

    NASA Technical Reports Server (NTRS)

    Kuo, C. Y.; Modena, T. D.

    1979-01-01

    An existing, three-dimensional, Eulerian-Lagrangian finite-difference model was modified and used to examine the transport processes of dumped sewage sludge in the New York Bight. Both in situ and laboratory data were utilized in an attempt to approximate model inputs such as mean current speed, horizontal diffusion coefficients, particle size distributions, and specific gravities. The results presented are a quantitative description of the fate of a negatively buoyant sewage sludge plume resulting from continuous and instantaneous barge releases. Concentrations of the sludge near the surface were compared qualitatively with those remotely sensed. Laboratory study was performed to investigate the behavior of sewage sludge dumping in various ambient density conditions.

  11. Coastal pollution limits pelagic larval dispersal.

    PubMed

    Puritz, Jonathan B; Toonen, Robert J

    2011-01-01

    The ecological impact of large coastal human populations on marine ecosystems remains relatively unknown. Here, we examine the population structure of Patiria miniata, the bat star, and correlate genetic distances with a model based on flow rates and proximity to P. miniata populations for the four major stormwater runoff and wastewater effluent sources of the Southern California Bight. We show that overall genetic connectivity is high (F(ST)~0.005); however, multivariate analyses show that genetic structure is highly correlated with anthropogenic inputs. The best models included both stormwater and wastewater variables and explained between 26.55 and 93.69% of the observed structure. Additionally, regressions between allelic richness and distance to sources show that populations near anthropogenic pollution have reduced genetic diversity. Our results indicate that anthropogenic runoff and effluent are acting as barriers to larval dispersal, effectively isolating a high gene flow species that is virtually free of direct human impact.

  12. Die Biomasse mariner Makrobenthos-Gesellschaften im Einflußbereich der Klärschlammverklappung vor der Elbemündung

    NASA Astrophysics Data System (ADS)

    Mühlenhardt-Siegel, U.

    1981-12-01

    The macrofauna of a dumping area in the eastern part of the German Bight (North Sea) was investigated in July, August and November, 1978 at five stations situated on a transect including central and peripheral areas of the dumping region. Abundance and biomass (ash free dry weight) of the macrofauna and its variation from July to November were analysed as well as the biomass of different taxa. Molluscs dominated over polychaetes, crustaceans and echinoderms. A positive correlation seemed to exist between mud content and biomass at the peripherally situated stations. In the central sewage sludge area, however, the biomass values were reduced. In late autumn the biomass decreased in the entire area due to the death of Diastylis rathkei, Abra alba and Pectinaria koreni. These species were replaced by the mollusc Nucula turgida and polychaete Nephtys hombergii. In autumn the biomass values also showed a distinct minimum at the central stations.

  13. ERTS computer compatible tape data processing and analysis. Appendix 1: The utility of imaging radars for the study of lake ice

    NASA Technical Reports Server (NTRS)

    Polcyn, F. C.; Thomson, F. J.; Porcello, L. J.; Sattinger, I. J.; Malila, W. A.; Wezernak, C. T.; Horvath, R.; Vincent, R. K. (Principal Investigator); Bryan, M. L.

    1972-01-01

    There are no author-identified significant results in this report. Remotely sensed multispectral scanner and return beam vidicon imagery from ERTS-1 is being used for: (1) water depth measurements in the Virgin Islands and Upper Lake Michigan areas; (2) mapping of the Yellowstone National Park; (3) assessment of atmospheric effects in Colorado; (4) lake ice surveillance in Canada and Great Lakes areas; (5) recreational land use in Southeast Michigan; (6) International Field Year on the Great Lakes investigations of Lake Ontario; (7) image enhancement of multispectral scanner data using existing techniques; (8) water quality monitoring of the New York Bight, Tampa Bay, Lake Michigan, Santa Barbara Channel, and Lake Erie; (9) oil pollution detection in the Chesapeake Bay, Gulf of Mexico southwest of New Orleans, and Santa Barbara Channel; and (10) mapping iron compounds in the Wind River Mountains.

  14. Methane production from bicarbonate and acetate in an anoxic marine sediment

    NASA Technical Reports Server (NTRS)

    Crill, P. M.; Martens, C. S.

    1986-01-01

    Methane production from C-14 labeled bicarbonate and acetate was measured over the top 28 cm of anoxic Cape Lookout Bight sediments during the summer of 1983. The depth distribution and magnitude of summed radioisotopically determined rates compare well with previous measurements of total methane production and the sediment-water methane flux. Methane production from CO2 reduction and acetate fermentation accounts for greater than 80 percent of the total production rate and sediment-water flux. Methane production from bicarbonate was found to occur in all depth intervals sampled except those in the top 2 cm, whereas significant methane production from acetate only occurred at depths below 10 cm where sulfate was exhausted. Acetate provided 20 to 29 percent of the measured methane production integrated over the top 30 cm of the sediments.

  15. DOE West Coast Basin program, California Basin Study: Progress report 4, (July 1986-June 1987)

    SciTech Connect

    Small, L.F.; Huh, Chih-An

    1987-06-01

    The overall objective of our research is to understand the transport pathways and mass balances of selected metabolically active and inactive chemical species in the Santa Monica/San Pedro Basins. One focus is to examine the role of zooplankton and micronekton in the cycling and remineralization of chemical materials in the Southern California Bight, with particular reference to C, N and certain radionuclides and trace metals. A second focus is to examine these same radionuclides and trace metals in other reservoirs besides the zooplankton (i.e., in seawater, sediment trap material and bottom sediments). Knowledge of the rates, routes and reservoirs of these nuclides and metals should lead to a cogent model for these elements in Santa Monica/San Pedro Basins. 28 refs., 13 figs., 7 tabs.

  16. Spatial, seasonal and vertical distributions of currently-used pesticides in the marine boundary layer of the North Sea

    NASA Astrophysics Data System (ADS)

    Mai, Carolin; Theobald, Norbert; Lammel, Gerhard; Hühnerfuss, Heinrich

    2013-08-01

    Pesticides are transported beyond source regions and reach coastal waters and shelf seas. 23 representatives of six chemical classes of currently-used pesticides (CUPs) were simultaneously quantified in the marine boundary layer and the surface seawater of the German Bight and the central North Sea in 2009 and 2010.Terbuthylazine, metolachlor, metazachlor, pendimethalin and trifluralin exhibited the highest concentrations, seasonally highly variable. Advection of contaminated air from land and subsequent atmospheric deposition was shown to contribute to surface seawater contamination significantly, in particular in regions beyond riverine input and during the main seasons of application in agriculture. Deposition was most significant for the seasonal and spatial distributions of pendimethalin and trifluralin. Atrazine and simazine levels in the air are lower than 1-2 decades ago.

  17. Utilization, cycling and vertical transport of particulate organic matter in the coastal marine environment

    SciTech Connect

    Landry, M.R.

    1992-01-01

    This project was funded as part of the California Basin Study (CaBS), a DOE-funded regional program investigating production, cycling, transport, and fate of organic matter, chemical tracers, and pollutants in the Southern California Bight. The study area, adjacent to Los Angeles, was of programmatic interest due to its heavy concentration of energy-related activities, including offshore oil drilling and natural seeps, shipping, nuclear power facilities, and industrial and municipal ocean waste disposal. It was also of scientific interest because the wide continental margin in the region, pot-marked with natural sediment traps in the form of deep basins with restricted inputs and outputs, was ideal for integrating water-column and benthic studies and tracing the fates of in situ production and introduced pollutants. Our role in the CABS Program was to investigate the flux of particulate matter through the water column, emphasizing the relationship between macrozooplankton feeding and particle flux.

  18. Utilization, cycling and vertical transport of particulate organic matter in the coastal marine environment. Final project report, November 15, 1987--May 14, 1992

    SciTech Connect

    Landry, M.R.

    1992-10-01

    This project was funded as part of the California Basin Study (CaBS), a DOE-funded regional program investigating production, cycling, transport, and fate of organic matter, chemical tracers, and pollutants in the Southern California Bight. The study area, adjacent to Los Angeles, was of programmatic interest due to its heavy concentration of energy-related activities, including offshore oil drilling and natural seeps, shipping, nuclear power facilities, and industrial and municipal ocean waste disposal. It was also of scientific interest because the wide continental margin in the region, pot-marked with natural sediment traps in the form of deep basins with restricted inputs and outputs, was ideal for integrating water-column and benthic studies and tracing the fates of in situ production and introduced pollutants. Our role in the CABS Program was to investigate the flux of particulate matter through the water column, emphasizing the relationship between macrozooplankton feeding and particle flux.

  19. Natural abundances of carbon isotopes in acetate from a coastal marine sediment

    NASA Technical Reports Server (NTRS)

    Blair, N. E.; Martens, C. S.; Des Marais, D. J.

    1987-01-01

    Measurements of the natural abundances of carbon isotopes were made in acetate samples isolated from the anoxic marine sediment of Cape Lookout Bight, North Carolina. The typical value of the total acetate carbon isotope ratio (delta 13C) was -16.1 +/- 0.2 per mil. The methyl and carboxyl groups were determined to be -26.4 +/- 0.3 and -6.0 +/- 0.3 per mil, respectively, for one sample. The isotopic composition of the acetate is thought to have resulted from isotopic discriminations that occurred during the cycling of that molecule. Measurements of this type, which have not been made previously in the natural environment, may provide information about the dominant microbial pathways in anoxic sediments as well as the processes that influence the carbon isotopic composition of biogenic methane from many sources.

  20. Predation on barnacles of intertidal and subtidal mussel beds in the Wadden Sea

    NASA Astrophysics Data System (ADS)

    Buschbaum, Christian

    2002-04-01

    Balanids are the numerically dominant epibionts on mussel beds in the Wadden Sea. Near the island of Sylt (German Bight, North Sea), Semibalanus balanoides dominated intertidally and Balanus crenatus subtidally. Field experiments were conducted to test the effects of predation on the density of barnacle recruits. Subtidally, predator exclusion resulted in significantly increased abundances of B. crenatus, while predator exclusion had no significant effects on the density of S. balanoides intertidally. It is suggested that recruitment of B. crenatus to subtidal mussel beds is strongly affected by adult shore crabs ( Carcinus maenas) and juvenile starfish ( Asterias rubens), whereas recruits of S. balanoides in the intertidal zone are mainly influenced by grazing and bulldozing of the very abundant periwinkle Littorina littorea, which is rare subtidally. Thus, not only do the barnacle species differ between intertidal and subtidal mussel beds, but the biotic control factors do so as well.

  1. Tracking contaminants down the Mississippi

    USGS Publications Warehouse

    Swarzenski, P.; Campbell, P.

    2004-01-01

    The Mississippi River and its last major downstream distributary, the Atchafalaya River, provide approximately 90 percent of the freshwater input to the Gulf of Mexico. Analyses of sediment cores using organic and inorganic tracers as well as bethic foraminifera appear to provide a reliable record of the historic variability of hypoxia in the northern Gulf of Mexico over the past few centuries. Natural variability in hypoxic events may be driven largely by flooding cycles of El Nin??o/La Nin??a prior to recent increases in nutrient loading. Specifically, large floods in 1979, 1983, 1993 and 1998, compounded with the widespread use of fertilizers, also appear at least partially responsible for the recent (post-1980) dramatic increase of hypoxic events in the Mississippi Bight.

  2. Carbon Isotope Biogeochemistry of Methane from Anoxic Sediments

    NASA Technical Reports Server (NTRS)

    Blair, Neal E.

    1993-01-01

    The isotopic composition of naturally occurring methane was used to constrain the tropospheric budget of that radiatively active gas. Numerous studies have shown that the isotopic composition is not constant, even for a specific source, and may vary temporally and spatially. The objective was to develop a process-level model that reproduced the seasonal variations in the C-13/C-12 composition of methane observed at the coastal site, Cape Lookout Bight, NC. Details of the mass balance are provided. Experiments and models designed to determine what factors incluence C-13/C-12 ratio of dissolved CO2 are reported. All the factors described were combined in a model that faithfully reproduces the seasonal C-13/C-12 variations observed at Cape Lookout. The model is described.

  3. A numerical model investigation of the formation and persistence of an erosion hotspot

    USGS Publications Warehouse

    Hansen, Jeff E.; Elias, Edwin; List, Jeffrey H.; Barnard, Patrick L.

    2011-01-01

    A Delft3D-SWAN coupled flow and wave model was constructed for the San Francisco Bight with high-resolution at 7 km-long Ocean Beach, a high-energy beach located immediately south of the Golden Gate, the sole entrance to San Francisco Bay. The model was used to investigate tidal and wave-induced flows, basic forcing terms, and potential sediment transport in an area in the southern portion of Ocean Beach that has eroded significantly over the last several decades. The model predicted flow patterns that were favorable for sediment removal from the area and net erosion from the surf-zone. Analysis of the forcing terms driving surf-zone flows revealed that wave refraction over an exposed wastewater outfall pipe between the 12 and 15 m isobaths introduces a perturbation in the wave field that results in erosion-causing flows. Modeled erosion agreed well with five years of topographic survey data from the area.

  4. Toroidal magnet system

    DOEpatents

    Ohkawa, Tihiro; Baker, Charles C.

    1981-01-01

    In a plasma device having a toroidal plasma containment vessel, a toroidal field-generating coil system includes fixed linking coils each formed of first and second sections with the first section passing through a central opening through the containment vessel and the second section completing the linking coil to link the containment vessel. A plurality of removable unlinked coils are each formed of first and second C-shaped sections joined to each other at their open ends with their bights spaced apart. The second C-shaped section of each movable coil is removably mounted adjacent the second section of a linking coil, with the containment vessel disposed between the open ends of the first and second C-shaped sections. Electric current is passed through the linking and removable coils in opposite sense in the respective adjacent second sections to produce a net toroidal field.

  5. Absolute tracer dye concentration using airborne laser-induced water Raman backscatter

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1981-01-01

    The use of simultaneous airborne-laser-induced dye fluorescence and water Raman backscatter to measure the absolute concentration of an ocean-dispersed tracer dye is discussed. Theoretical considerations of the calculation of dye concentration by the numerical comparison of airborne laser-induced fluorescence spectra with laboratory spectra for known dye concentrations using the 3400/cm OH-stretch water Raman scatter as a calibration signal are presented which show that minimum errors are obtained and no data concerning water mass transmission properties are required when the laser wavelength is chosen to yield a Raman signal near the dye emission band. Results of field experiments conducted with an airborne conical scan lidar over a site in New York Bight into which rhodamine dye had been injected in a study of oil spill dispersion are then indicated which resulted in a contour map of dye concentrations, with a minimum detectable dye concentration of approximately 2 ppb by weight.

  6. A study on the interactions of the MSL and the movement of amphydromic points and their impact on the mean tidal range in the North Sea

    NASA Astrophysics Data System (ADS)

    Jensen, Juergen; Arns, Arne

    2010-05-01

    According to IPCC (2007), the global average sea level rise projections are significant to the end of the century. Even the current time series analyses of the North Sea show, that there have been significant changes in the tidal regime starting from 1955 to 1960. While one can observe an appreciable increase in the mean tidal high water (MHW) from then on, the mean tidal low water (MLW) behaves contrary; as difference between the MHW and the MLW, the mean tidal range (MTR) in the German Bight rises (JENSEN and MUDERSBACH 2007). The reason for this behaviour is not as yet clarified entirely, but there have been many theoretical approaches ascribing the changes in the MTR either to anthropogenic or natural processes. The changes in the MTR can not only be observed in the German Bight, but also along the British east coast. However the MTR along the British coast shows a small decrease being the largest in the area of Aberdeen and reduces in northern and southern direction respectively reverses in the most southern part of England. According to JEVREJEVA et al. (2006) there is a significant change in the sea level of the north-eastern Atlantic starting at the same time as mentioned above, which is characterized by an uncommon increase. A tidal wave is influenced by the coriolis force which causes a deflection in the currents towards the right side of the direction of the motion in the northern hemisphere. In wide and at the end closed channels - what the North Sea may be considered as - the reflection of the tidal wave away from the boundary results in two waves travelling in the opposite directions. The resulting waves are oscillating around a time dependent position which is called an amphidromic point; in this position, the waves amplitude respectively the tidal range is zero. In the North Sea there are two amphidromic systems and a third incomplete amphidromic system. In the North Sea the average tidal range is between 0 to 8 metres. With an increasing distance

  7. Do East Australian Current anticyclonic eddies leave the Tasman Sea?

    NASA Astrophysics Data System (ADS)

    Pilo, Gabriela S.; Oke, Peter R.; Rykova, Tatiana; Coleman, Richard; Ridgway, Ken

    2015-12-01

    Using satellite altimetry and high-resolution model output we analyze the pathway of large, long-lived anticyclonic eddies that originate near the East Australian Current (EAC) separation point. We show that 25-30% of these eddies propagate southward, around Tasmania, leave the Tasman Sea, and decay in the Great Australian Bight. This pathway has not been previously documented owing to poor satellite sampling off eastern Tasmania. As eddies propagate southward, they often "stall" for several months at near-constant latitude. Along the pathway eddies become increasingly barotropic. Eddy intensity is primarily influenced by merging with other eddies and a gradual decay otherwise. Surface temperature anomaly associated with anticyclonic eddies changes as they propagate, while surface salinity anomaly tends to remain relatively unchanged as they propagate.

  8. Active-passive airborne ocean color measurement. II - Applications

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.; Yungel, J. K.

    1986-01-01

    Reported here for the first time is the use of a single airborne instrument to make concurrent measurements of oceanic chlorophyll concentration by (1) laser-induced fluorescence, (2) passive upwelling radiance, and (3) solar-induced chlorophyll fluorescence. Results from field experiments conducted with the NASA airborne oceanographic lidar (AOL) in the New York Bight demonstrate the capability of a single active-passive instrument to perform new and potentially important ocean color studies related to (1) active lidar validation of passive ocean color in-water algorithms, (2) chlorophyll a in vivo fluorescence yield variability, (3) calibration of active multichannel lidar systems, (4) effect of sea state on passive and active ocean color measurements, (5) laser/solar-induced chlorophyll fluorescence investigations, and (6) subsequent improvement of satellite-borne ocean color scanners. For validation and comparison purposes a separate passive ocean color sensor was also flown along with the new active-passive sensor during these initial field trials.

  9. Large CO2 reductions via offshore wind power matched to inherent storage in energy end-uses

    NASA Astrophysics Data System (ADS)

    Kempton, Willett; Archer, Cristina L.; Dhanju, Amardeep; Garvine, Richard W.; Jacobson, Mark Z.

    2007-01-01

    We develop methods for assessing offshore wind resources, using a model of the vertical structure of the planetary boundary layer (PBL) over water and a wind-electric technology analysis linking turbine and tower limitations to bathymetry and continental shelf geology. These methods are tested by matching the winds of the Middle-Atlantic Bight (MAB) to energy demand in the adjacent states (Massachusetts through North Carolina, U.S.A.). We find that the MAB wind resource can produce 330 GW average electrical power, a resource exceeding the region's current summed demand for 73 GW of electricity, 29 GW of light vehicle fuels (now gasoline), and 83 GW of building fuels (now distillate fuel oil and natural gas). Supplying these end-uses with MAB wind power would reduce by 68% the region's CO2 emissions, and reduce by 57% its greenhouse gas forcing. These percentages are in the range of the global reductions needed to stabilize climate.

  10. Seasonal variations in the stable carbon isotopic signature of biogenic methane in a coastal sediment

    NASA Technical Reports Server (NTRS)

    Martens, C. S.; Green, C. D.; Blair, N. E.; Des Marais, D. J.

    1986-01-01

    Systematic seasonal variations in the stable carbon isotopic signature of methane gas occur in the anoxic sediments of Cape Lookout Bight, a lagoonal basin on North Carolina's Outer Banks. Values for the carbon isotope ratio of methane range from -57.3 per mil during summer to -68.5 per mil during winter in gas bubbles with an average methane content of 95 percent. The variations are hypothesized to result from changes in the pathways of microbial methane production and cycling of key substrates including acetate and hydrogen. The use of stable isotopic signatures to investigate the global methane cycle through mass balance calculations, involving various sediment and soil biogenic sources, appears to require seasonally averaged data from individual sites.

  11. On the "hidden" phytoplankton blooms on Australia's southern shelves

    NASA Astrophysics Data System (ADS)

    Kämpf, Jochen; Kavi, Ankit

    2017-02-01

    Phytoplankton blooms on Australia's southern shelves are revisited using satellite-derived monthly data of chlorophyll a concentrations for the period 2003-2015. It is known that the region hosts a seasonal coastal upwelling system that develops in austral summer (January-March) with chlorophyll a concentrations of >2 mg/m3. While this summer upwelling is spatially limited to a few hot spots, here we show that widespread phytoplankton blooms of moderate ( 1 mg/m3) chlorophyll a concentrations develop during autumn and early winter on most of Australia's extensive southern shelves—from the vast shelves of the Great Australian Bight (GAB) in the west to Bass Strait in the east. This surprising finding disproves the widespread belief that shelf waters of the GAB are generally oligotrophic and may explain the relatively high abundance of both forage fish (sardines) and upper trophic-level predators (e.g., tuna and whales) in the region.

  12. Carbonate shelf edge off southern Australia: A prograding open-platform margin

    NASA Astrophysics Data System (ADS)

    James, Noel P.; von der Borch, Christopher C.

    1991-10-01

    The southern continental margin of Australia is an extensive shelf that has been a site of cool-water carbonate deposition since Eocene time. The platform has no rim and is swept by high-energy waves and swells throughout the year. The shelf is deep (40 to 100 m) and typified by bryozoan-rich sediments. The shelf margin is a gentle incline that becomes progressively steeper seaward, except where it laps down onto offshore terraces. The edge of the Eucla Platform in the Great Australian Bight is used to illustrate that the margin is a series of extensive prograding clinoforms. Progradation is interpreted to be the result of off-shelf sediment transport and in-place carbonate production by actively growing deep-water bryozoa and sponges. This area is a potential model for ancient high-energy platform margins during geologic periods when large skeletal reef-building metazoans were scarce.

  13. Late Cenozoic tectonic evolution of southwestern California

    NASA Technical Reports Server (NTRS)

    Sedlock, Richard L.; Hamilton, Douglas H.

    1991-01-01

    Geologic and geophysical data from southern California and adjoining areas are used to reconstruct the tectonic evolution of the southern Coast Ranges, western Transverse Ranges, and borderland regions since 30 Myr ago. Premises include specified relative plate motions for times prior to 10.5 Myr ago and after 3 Myr ago, a mid-Tertiary bight in the continental margin, midcrustal detachment faults, rotation of the western Transverse Ranges about an eastern pivot, and specified fault displacement histories. Prior to 18 Myr ago, about 90 percent of the tangential component of Pacific-North America relative motion was accommodated on an offshore dextral fault system near the toe of the continental slope. From 18 to 5.5 Myr ago, dextral slip was accommodated predominantly on the offshore system but also on a second, inboard system that included the San Andreas fault.

  14. Material transport from the near shore to the basinal environment in the southern Baltic Sea. II: Synthesis of data on origin and properties of material

    NASA Astrophysics Data System (ADS)

    Emeis, K.; Christiansen, C.; Edelvang, K.; Jähmlich, S.; Kozuch, J.; Laima, M.; Leipe, T.; Löffler, A.; Lund-Hansen, L. C.; Miltner, A.; Pazdro, K.; Pempkowiak, J.; Pollehne, F.; Shimmield, T.; Voss, M.; Witt, G.

    2002-07-01

    The Pomeranian Bight (southern Baltic Sea) is a mixing zone between waters of the Baltic Proper and the river Oder, which drains a densely populated and highly industrialised catchment of central Europe. The bight is a nondepositional area, and all material produced in its water column, from erosion of strata at the seafloor and cliffs, and delivered by rivers, is transported near the seafloor to the depositional areas of the Arkona, Bornholm and Gdansk basins. In this contribution, we assess the origin, transformation and mass fluxes of material through the bight based on an integrated field study conducted in the period 1996-1998. The transport mechanism is by wave- and current-induced resuspension and settling cycles, which effectively enrich organic-rich material and associated substances (organic pollutants, heavy metals) in deeper water; the estimated transport time is less than 6 months. The phases in which the material is transported are suspended matter in the water column, a particle- and aggregate-rich benthic boundary layer of <1 m above the seafloor and a layer of fluffy material fed from the two other sources that covers the sandy near-shore sediments as a discrete phase; it collects up to 130 g m -2 of particulate material after quiescent periods lasting several days. It is easily resuspended at shear velocities around 5 cm s -1 and is recycled into the suspended matter and benthic boundary layer pools of material. In deeper waters (>20 m water depth), the fluffy layer is not readily distinguished from the underlying soft, organic-rich sediment and the change in physical and chemical properties is gradual. The organic matter passing through the coastal zone in the southern Baltic is unaffected by biological or chemical modifications in composition. We find no evidence for a preferential removal of nitrogen or phosphorus, even if the speciation of phosphorus changes from biological compounds to minerals. The compositional changes which we see, i

  15. Sulfur and carbon cycling in organic-rich marine sediments

    NASA Technical Reports Server (NTRS)

    Martens, C. S.

    1985-01-01

    Nearshore, continental shelf, and slope sediments are important sites of microbially mediated carbon and sulfur cycling. Marine geochemists investigated the rates and mechanisms of cycling processes in these environments by chemical distribution studies, in situ rate measurements, and steady state kinetic modeling. Pore water chemical distributions, sulfate reduction rates, and sediment water chemical fluxes were used to describe cycling on a ten year time scale in a small, rapidly depositing coastal basin, Cape Lookout Bight, and at general sites on the upper continental slope off North Carolina, U.S.A. In combination with 210 Pb sediment accumulation rates, these data were used to establish quantitative carbon and sulfur budgets as well as the relative importance of sulfate reduction and methanogeneis as the last steps in the degradation of organic matter.

  16. Sub-kilometer length scales in coastal waters

    NASA Astrophysics Data System (ADS)

    Blackwell, Shelley M.; Moline, Mark A.; Schaffner, Andrew; Garrison, Thomas; Chang, Grace

    2008-02-01

    Patchiness or spatial variability is ubiquitous in marine systems. With increasing anthropogenic impacts to coastal resources and coastal systems being disproportionately large contributors to ocean productivity, identifying the spatial scales of this patchiness, particularly in coastal waters, is of critical importance to understand coastal ecosystem dynamics. The current work focuses on fine scale structure in three coastal regions. More specifically, we utilize variogram analyses to identify sub-kilometer scales of variability in biological and physical parameters measured by an autonomous underwater vehicle (AUV) in the Mid-Atlantic Bight, Monterey Bay, and in San Luis Obispo Bay between 2001 and 2004. Critical scales of variability in density, turbidity, fluorescence, and bioluminescence are examined as a function of depth and distance offshore. Furthermore, the effects of undersampling are assessed using predictive error analysis. Results indicate the presence of scales of variability ranging from 10s to 100s of meters and provide valuable insight for sampling design and resource allocation for future studies.

  17. The carbon isotope biogeochemistry of methane production in anoxic sediments. 1: Field observations

    NASA Technical Reports Server (NTRS)

    Blair, Neal E.; Boehme, Susan E.; Carter, W. Dale, Jr.

    1993-01-01

    The natural abundance C-13/C-12 ratio of methane from anoxic marine and freshwater sediments in temperate climates varies seasonally. Carbon isotopic measurements of the methanogenic precursors, acetate and dissolved inorganic carbon, from the marine sediments of Cape Lookout Bight, North Carolina were used to determine the sources of the seasonal variations at that site. Movement of the methanogenic zone over an isotopic gradient within the dissolved CO2 pool appears to be the dominant control of the methane C-13/C-12 ratio from February to June. The onset of acetoclastic methane-production is a second important controlling process during mid-summer. An apparent temperature dependence on the fractionation factor for CO2-reduction may have a significant influence on the isotopic composition of methane throughout the year.

  18. Seasonal variations in the stable carbon isotopic signature of biogenic methane in a coastal sediment

    SciTech Connect

    Martens, C.S.; Blair, N.E.; Green, C.D.; Des Marais, D.J.

    1986-09-19

    Systematic seasonal variations in the stable carbon isotopic signature of methane gas occur in the anoxic sediments of Cape Lookout Bight, a lagoonal basin on North Carolina's Outer Banks. Values for the carbon isotope ratio (delta /sup 13/C) of methane range from -57.3 per mil during summer to -68.5 per mil during winter in gas bubbles with an average methane content of 95%. The variations are hypothesized to result from changes in the pathways of microbial methane production and cycling of key substrates including acetate and hydrogen. The use of stable isotopic signatures to investigate the global methane cycle through mass balance calculations, involving various sediment and soil biogenic sources, appears to require seasonally averaged data from individual sites. 17 references, 2 figures, 2 tables.

  19. Nutrient transfer in three contrasting NW European watersheds: the Seine, Somme, and Scheldt Rivers. A comparative application of the Seneque/Riverstrahler model.

    PubMed

    Thieu, Vincent; Billen, Gilles; Garnier, Josette

    2009-04-01

    An understanding of the ecological functioning of an aquatic continuum on a multi-regional scale relies on the ability to collect suitable descriptive information. Here, the deterministic Seneque/Riverstrahler model, linking biogeochemistry with the constraints set by geomorphology and anthropogenic activities, was fully implemented to study the Seine, Somme, and Scheldt Rivers. Reasonable agreement was found between calculated and observed nutrient fluxes for both seasonal and inter-annual variations along the networks. Nutrient budgets underline: i) a clear partition of diffuse and point sources with respect to the specific activities of the watersheds, ii) the importance of riparian retention, responsible for 25-50% of nitrogen retention, iii) the role played by benthic processes, resulting in the retention of up to 45% of the phosphorus and 35% of the silica entering the river systems. Nutrient ratios confirmed that fluxes to the Eastern Southern Bight of the North Sea are imbalanced, supporting the potential for undesirable algal blooms.

  20. Recurring patterns in bacterioplankton dynamics during coastal spring algae blooms

    PubMed Central

    Teeling, Hanno; Fuchs, Bernhard M; Bennke, Christin M; Krüger, Karen; Chafee, Meghan; Kappelmann, Lennart; Reintjes, Greta; Waldmann, Jost; Quast, Christian; Glöckner, Frank Oliver; Lucas, Judith; Wichels, Antje; Gerdts, Gunnar; Wiltshire, Karen H; Amann, Rudolf I

    2016-01-01

    A process of global importance in carbon cycling is the remineralization of algae biomass by heterotrophic bacteria, most notably during massive marine algae blooms. Such blooms can trigger secondary blooms of planktonic bacteria that consist of swift successions of distinct bacterial clades, most prominently members of the Flavobacteriia, Gammaproteobacteria and the alphaproteobacterial Roseobacter clade. We investigated such successions during spring phytoplankton blooms in the southern North Sea (German Bight) for four consecutive years. Dense sampling and high-resolution taxonomic analyses allowed the detection of recurring patterns down to the genus level. Metagenome analyses also revealed recurrent patterns at the functional level, in particular with respect to algal polysaccharide degradation genes. We, therefore, hypothesize that even though there is substantial inter-annual variation between spring phytoplankton blooms, the accompanying succession of bacterial clades is largely governed by deterministic principles such as substrate-induced forcing. DOI: http://dx.doi.org/10.7554/eLife.11888.001 PMID:27054497

  1. Highlights of the First 15 Months of Aquarius Salinity Measurements

    NASA Technical Reports Server (NTRS)

    Lagerloef, Gary S. E.; Kao, Hsun-Ying; Wentz, Frank; LeVine, David M.; Yueh, Simon H.; Feldman, Gene C.

    2012-01-01

    Aquarius satellite salinity measurements are resolving the major global and regional spatial patterns, and temporal variations, since the start of routine data collection on 25 August 2011. This description includes the principal seasonal variations over the first annual cycle as observed by the mission. In particular, we identify the evolution of low salinity anomalies associated with the Atlantic and Pacific intertropical convergence zones (ITCZ), major river outflows such as the Amazon, a seasonal low salinity anomaly in the Panama bight, and other features. We also explore the links that the salinity variations have with precipitation and surface currents. We then will describe the variations related to the presently evolving 2012 El Nino, now evident, as it progresses through the summer and fall 2012. We conclude with a brief summary of the Aquarius data products and validation

  2. Biochemical characteristics and virulence of environmental group F bacteria isolated in the United States.

    PubMed Central

    Seidler, R J; Allen, D A; Colwell, R R; Joseph, S W; Daily, O P

    1980-01-01

    Bacteria phenotypically resembling Aeromonas hydrophila, but requiring NaCl for growth, have been isolated form the New York Bight. The bacteria proved to be identical to group F organisms isolated from cases of human diarrhea in Indonesia and Bangladesh. Anaerogenic strains initiated responses in Y-1 tissue culture and rabbit ileal loop, consistent with those associated with cytotoxin- and enterotoxin-producing Aeromonas spp. strains. Separation on the basis of production of gas from glucose by group F strains was correlated with differences in mean guanine-plus-cytosine deoxyribonucleic acid base composition and in deoxyribonucleic acid relative reassociation. Both aerogenic and anaerogenic strains reassociated to a significantly greater extent with Vibrio spp. than with Aeromonas spp. and indeed should be considered a new species of the genus Vibrio. PMID:7425623

  3. Effects of chemical dispersants on oil spill drift paths in the German Bight—probabilistic assessment based on numerical ensemble simulations

    NASA Astrophysics Data System (ADS)

    Schwichtenberg, Fabian; Callies, Ulrich; Groll, Nikolaus; Maßmann, Silvia

    2017-04-01

    Oil dispersed in the water column remains sheltered from wind forcing, so that an altered drift path is a key consequence of using chemical dispersants. In this study, ensemble simulations were conducted based on 7 years of simulated atmospheric and marine conditions, evaluating 2,190 hypothetical spills from each of 636 cells of a regular grid covering the inner German Bight (SE North Sea). Each simulation compares two idealized setups assuming either undispersed or fully dispersed oil. Differences are summarized in a spatial map of probabilities that chemical dispersant applications would help prevent oil pollution from entering intertidal coastal areas of the Wadden Sea. High probabilities of success overlap strongly with coastal regions between 10 m and 20 m water depth, where the use of chemical dispersants for oil spill response is a particularly contentious topic. The present study prepares the ground for a more detailed net environmental benefit analysis (NEBA) accounting also for toxic effects.

  4. Pollutant transport among California regions

    NASA Astrophysics Data System (ADS)

    Angevine, Wayne M.; Brioude, Jerome; McKeen, Stuart; Holloway, John S.; Lerner, Brian M.; Goldstein, Allen H.; Guha, Abhinav; Andrews, Arlyn; Nowak, John B.; Evan, Stephanie; Fischer, Marc L.; Gilman, Jessica B.; Bon, Daniel

    2013-06-01

    Several regions within California have significant air quality issues. Transport of pollutants emitted in one region to another region may add to the impact of local emissions. In this work, Lagrangian particle dispersion model simulations show the amounts of tracers that are transported within and among four regions, Southern California, the San Francisco Bay Area, the Central Valley, and the rest of the state. The simulations cover May and June of 2010, the California Research at the Nexus of Air Quality and Climate Change experiment period. Tracers of automobile emissions and one type of agricultural emission are used. Tracer mixing ratios are compared to airborne and ground-based measurements. The age of tracers in each location is also presented. Vertical profiles and diurnal cycles help to clarify the transport process. As is well known, Southern California emissions are transported to the east and affect the desert areas, and Bay Area automobile emissions are an important source of pollutants in the San Joaquin Valley. A novel result is that the Southern California Bight is filled with a mixture of well-aged carbon monoxide tracer from Southern California and the Bay Area. Air over the Bight is also affected by the agricultural emissions represented by the agricultural tracer, dominantly from the Central Valley where its sources are largest. There is no indication of transport from Southern California to the Central Valley. Emissions from the Central Valley do make their way to Southern California, as shown by the agricultural tracer, but automobile emissions from the Valley are insignificant in Southern California.

  5. Gene Expression and Physiological Changes of Different Populations of the Long-Lived Bivalve Arctica islandica under Low Oxygen Conditions

    PubMed Central

    Philipp, Eva E. R.; Wessels, Wiebke; Gruber, Heike; Strahl, Julia; Wagner, Anika E.; Ernst, Insa M. A.; Rimbach, Gerald; Kraemer, Lars; Schreiber, Stefan; Abele, Doris; Rosenstiel, Philip

    2012-01-01

    The bivalve Arctica islandica is extremely long lived (>400 years) and can tolerate long periods of hypoxia and anoxia. European populations differ in maximum life spans (MLSP) from 40 years in the Baltic to >400 years around Iceland. Characteristic behavior of A. islandica involves phases of metabolic rate depression (MRD) during which the animals burry into the sediment for several days. During these phases the shell water oxygen concentrations reaches hypoxic to anoxic levels, which possibly support the long life span of some populations. We investigated gene regulation in A. islandica from a long-lived (MLSP 150 years) German Bight population and the short-lived Baltic Sea population, experimentally exposed to different oxygen levels. A new A. islandica transcriptome enabled the identification of genes important during hypoxia/anoxia events and, more generally, gene mining for putative stress response and (anti-) aging genes. Expression changes of a) antioxidant defense: Catalase, Glutathione peroxidase, manganese and copper-zinc Superoxide dismutase; b) oxygen sensing and general stress response: Hypoxia inducible factor alpha, Prolyl hydroxylase and Heat-shock protein 70; and c) anaerobic capacity: Malate dehydrogenase and Octopine dehydrogenase, related transcripts were investigated. Exposed to low oxygen, German Bight individuals suppressed transcription of all investigated genes, whereas Baltic Sea bivalves enhanced gene transcription under anoxic incubation (0 kPa) and, further, decreased these transcription levels again during 6 h of re-oxygenation. Hypoxic and anoxic exposure and subsequent re-oxygenation in Baltic Sea animals did not lead to increased protein oxidation or induction of apoptosis, emphasizing considerable hypoxia/re-oxygenation tolerance in this species. The data suggest that the energy saving effect of MRD may not be an attribute of Baltic Sea A. islandica chronically exposed to high environmental variability (oxygenation, temperature

  6. Spatial impact of the Oder river plume on water quality along the south-western Baltic coast.

    PubMed

    Schernewski, G; Neumann, T; Podsetchine, V; Siegel, H

    2001-11-01

    The Oder (Odra) river is the most important nutrient source and pollutant for the south-western Baltic Sea. Adjacent German-Polish coastal waters, the Oder (Szczecin) Lagoon and the Oder (Pomeranian) Bight therefore suffer from severe eutrophication and water quality problems. At the same time, summer (bathing) tourism is the most important economical factor in this coastal zone, especially on the islands of Usedom and Wolin. On the basis of model simulations and remote sensing data we analysed the spatial extent and variability of the Oder river plume in the lagoon and the Balic Sea in common summer situations and during the extreme Oder flood in August 1997. Water quality shows pronounced gradients between coastal waters and open Baltic Sea. In the lagoon, it usually takes more than 6 weeks until Oder water enters the large western bay, the Kleines Haff. During transport, degradation, transformation and sedimentation processes alter the water quality and prevent the inner coast of Usedom from direct impact of polluted Oder water. Ongoing nutrient supply promotes intensive algal proliferation in all parts of the lagoon and contributes to the low water transparency. Oder water passing the lagoon and entering the Baltic Sea is transported over long distances in narrow bands along the shore. Under easterly winds the water quality near well-known spas on Usedom is reduced due to Oder river plume impact. Upwelling effects can have negative impact on water quality, too. Intensive blooms of potentially toxic blue-green algae species, are the rule in the lagoon and frequent in the Oder Bight in summer. They are a hazard and limit the acceptance of swimming beaches at the inner coast of Usedom. Practical consequences of variable water quality gradients e.g. on hygienic water sampling are discussed.

  7. Genetic by environmental variation but no local adaptation in oysters (Crassostrea virginica).

    PubMed

    Hughes, A Randall; Hanley, Torrance C; Byers, James E; Grabowski, Jonathan H; Malek, Jennafer C; Piehler, Michael F; Kimbro, David L

    2017-01-01

    Functional trait variation within and across populations can strongly influence population, community, and ecosystem processes, but the relative contributions of genetic vs. environmental factors to this variation are often not clear, potentially complicating conservation and restoration efforts. For example, local adaptation, a particular type of genetic by environmental (G*E) interaction in which the fitness of a population in its own habitat is greater than in other habitats, is often invoked in management practices, even in the absence of supporting evidence. Despite increasing attention to the potential for G*E interactions, few studies have tested multiple populations and environments simultaneously, limiting our understanding of the spatial consistency in patterns of adaptive genetic variation. In addition, few studies explicitly differentiate adaptation in response to predation from other biological and environmental factors. We conducted a reciprocal transplant experiment of first-generation eastern oyster (Crassostrea virginica) juveniles from six populations across three field sites spanning 1000 km in the southeastern Atlantic Bight in both the presence and absence of predation to test for G*E variation in this economically valuable and ecologically important species. We documented significant G*E variation in survival and growth, yet there was no evidence for local adaptation. Condition varied across oyster cohorts: Offspring of northern populations had better condition than offspring from the center of our region. Oyster populations in the southeastern Atlantic Bight differ in juvenile survival, growth, and condition, yet offspring from local broodstock do not have higher survival or growth than those from farther away. In the absence of population-specific performance information, oyster restoration and aquaculture may benefit from incorporating multiple populations into their practices.

  8. Spatially-Resolved Influence of Temperature and Salinity on Stock and Recruitment Variability of Commercially Important Fishes in the North Sea

    PubMed Central

    Akimova, Anna; Núñez-Riboni, Ismael; Kempf, Alexander; Taylor, Marc H.

    2016-01-01

    Understanding of the processes affecting recruitment of commercially important fish species is one of the major challenges in fisheries science. Towards this aim, we investigated the relation between North Sea hydrography (temperature and salinity) and fish stock variables (recruitment, spawning stock biomass and pre-recruitment survival index) for 9 commercially important fishes using spatially-resolved cross-correlation analysis. We used high-resolution (0.2° × 0.2°) hydrographic data fields matching the maximal temporal extent of the fish population assessments (1948–2013). Our approach allowed for the identification of regions in the North Sea where environmental variables seem to be more influential on the fish stocks, as well as the regions of a lesser or nil influence. Our results confirmed previously demonstrated negative correlations between temperature and recruitment of cod and plaice and identified regions of the strongest correlations (German Bight for plaice and north-western North Sea for cod). We also revealed a positive correlation between herring spawning stock biomass and temperature in the Orkney-Shetland area, as well as a negative correlation between sole pre-recruitment survival index and temperature in the German Bight. A strong positive correlation between sprat stock variables and salinity in the central North Sea was also found. To our knowledge the results concerning correlations between North Sea hydrography and stocks’ dynamics of herring, sole and sprat are novel. The new information about spatial distribution of the correlation provides an additional help to identify mechanisms underlying these correlations. As an illustration of the utility of these results for fishery management, an example is provided that incorporates the identified environmental covariates in stock-recruitment models. PMID:27584155

  9. Erosion of fine-grained sediment in the Hudson Shelf Valley, offshore of New York

    NASA Astrophysics Data System (ADS)

    Traykovski, P.; Harris, C. K.; Butman, B.; ten Brink, M. R.

    2001-05-01

    The Hudson Shelf Valley, the submerged ancestral drainage channel of the Hudson River, is a major topographic feature on the continental shelf of the New York Bight. The area near the head of the valley has been used for disposal of a wide variety of material, including dredged material (since the late 1800's) and sewage sludge (between 1972 and 1987). While the shelf is covered by primarily sandy sediments, finer sediments are found in the valley; these fine sediments have elevated concentrations of heavy metals and other contaminants. In order to understand the fate of these contaminated sediments in the winter of 1999-2000 an array of six tripods (four along the valley axis and 2 on the adjacent shelf) was deployed in the Valley and in the New York Bight to measure the regional pattern of sediment transport. At two sites (one at the head of the valley and one in the axis of the upper valley) where the surficial sediments are silty sand or sandy silt, erosion of up to 15 cm of sediment was observed under the tripods using an acoustic altimeter. The erosion took place over the first two months of the deployment in steps of 1 to 3 cm during 2 to 5 day periods of high wave energy and/or strong mean currents. The critical stress for resuspension/erosion increased as the bed eroded, thus ultimately limiting the amount of erosion. Since this large erosion rate is unlikely to be sustainable over large areas and over longer time scales, the observed erosion suggests that there may be mobile pools of fine sediment over more consolidated sediments that are easily erodable and transported during high energy events.

  10. Gulf Stream Power Characteristics near Cape Hatteras; Regional Model vs. Direct Current Observations

    NASA Astrophysics Data System (ADS)

    Lowcher, C.; Bane, J.; Gong, Y.; He, R.; Muglia, M.

    2014-12-01

    The Gulf Stream has current velocities reaching approximately 2 meters per second, which distinguish it as a potential source of marine hydrokinetic (MHK) energy. The upper continental slope off Cape Hatteras is a desirable area for development of offshore renewable energy because of the closeness of the Gulf Stream to the shelf edge and its minimal meanderings there. Using data from a moored 150-kHz ADCP and from the Mid-Atlantic Bight and South Atlantic Bight (MABSAB) ocean circulation model, MHK power characteristics have been computed for this area. These calculations quantify the Gulf Stream power resource and its temporal and spatial variations. During August 2013 - April 2014 at the moored ADCP site 30 meters below the surface and within the Stream's cyclonic shear zone, a comparison of the ADCP and MABSAB model reveals that the average current speeds from the two sources are nearly identical and have a magnitude of 1.15 m/s. A comparison for the same time period was made for Betz power, which yielded an observed average of 0.8 kW/m2 and a model average of 0.7 kW/m2, a difference of about 13%. The model has shown to be more conservative than the ADCP in its computation of current speed and Betz power, and it shows somewhat less variability than the ADCP in directionality of the Stream. Additionally, model data have been used to calculate annual average vector velocities and yearly Betz power averages for a number of years, and at various locations over the NC continental slope. These results depict the variation of the Stream's position along the NC coastline over the most recent years, and show that yearly averaged Betz power at a given location has significant inter-annual variations, with average power during one year being nearly four times greater than in another year.

  11. Persistent organochlorine pesticides and polychlorinated biphenyls in air of the North Sea region and air-sea exchange.

    PubMed

    Mai, Carolin; Theobald, Norbert; Hühnerfuss, Heinrich; Lammel, Gerhard

    2016-12-01

    Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were studied to determine occurrence, levels and spatial distribution in the marine atmosphere and surface seawater during cruises in the German Bight and the wider North Sea in spring and summer 2009-2010. In general, the concentrations found in air are similar to, or below, the levels at coastal or near-coastal sites in Europe. Hexachlorobenzene and α-hexachlorocyclohexane (α-HCH) were close to phase equilibrium, whereas net atmospheric deposition was observed for γ-HCH. The results suggest that declining trends of HCH in seawater have been continuing for γ-HCH but have somewhat levelled off for α-HCH. Dieldrin displayed a close to phase equilibrium in nearly all the sampling sites, except in the central southwestern part of the North Sea. Here atmospheric deposition dominates the air-sea exchange. This region, close to the English coast, showed remarkably increased surface seawater concentrations. This observation depended neither on riverine input nor on the elevated abundances of dieldrin in the air masses of central England. A net depositional flux of p,p'-DDE into the North Sea was indicated by both its abundance in the marine atmosphere and the changes in metabolite pattern observed in the surface water from the coast towards the open sea. The long-term trends show that the atmospheric concentrations of DDT and its metabolites are not declining. Riverine input is a major source of PCBs in the German Bight and the wider North Sea. Atmospheric deposition of the lower molecular weight PCBs (PCB28 and PCB52) was indicated as a major source for surface seawater pollution.

  12. The role of atmospheric forcing versus ocean advection during the extreme warming of the Northeast U.S. continental shelf in 2012

    NASA Astrophysics Data System (ADS)

    Chen, Ke; Gawarkiewicz, Glen; Kwon, Young-Oh; Zhang, Weifeng G.

    2015-06-01

    In the coastal ocean off the Northeast U.S., the sea surface temperature (SST) in the first half of 2012 was the highest on the record for the past roughly 150 years of recorded observations. The underlying dynamical processes responsible for this extreme event are examined using a numerical model, and the relative contributions of air-sea heat flux versus lateral ocean advective heat flux are quantified. The model accurately reproduces the observed vertical structure and the spatiotemporal characteristics of the thermohaline condition of the Gulf of Maine and the Middle Atlantic Bight waters during the anomalous warming period. Analysis of the model results show that the warming event was primarily driven by the anomalous air-sea heat flux, while the smaller contribution by the ocean advection worked against this flux by acting to cool the shelf. The anomalous air-sea heat flux exhibited a shelf-wide coherence, consistent with the shelf-wide warming pattern, while the ocean advective heat flux was dominated by localized, relatively smaller-scale processes. The anomalous cooling due to advection primarily resulted from the along-shelf heat flux divergence in the Gulf of Maine, while in the Middle Atlantic Bight the advective contribution from the along-shelf and cross-shelf heat flux divergences was comparable. The modeling results confirm the conclusion of the recent analysis of in situ data by Chen et al. (2014a) that the changes in the large-scale atmospheric circulation in the winter of 2011-2012 primarily caused the extreme warm anomaly in the spring of 2012. The effect of along-shelf or cross-shelf ocean advection on the warm anomalies from either the Scotian Shelf or adjacent continental slope was secondary.

  13. Characteristics of storms driving wave-induced seafloor mobility on the U.S. East Coast continental shelf

    USGS Publications Warehouse

    Dalyander, P. Soupy; Butman, Bradford

    2015-01-01

    This study investigates the relationship between spatial and temporal patterns of wave-driven sediment mobility events on the U.S. East Coast continental shelf and the characteristics of the storms responsible for them. Mobility events, defined as seafloor wave stress exceedance of the critical stress of 0.35 mm diameter sand (0.2160 Pa) for 12 or more hours, were identified from surface wave observations at National Data Buoy Center buoys in the Middle Atlantic Bight (MAB) and South Atlantic Bight (SAB) over the period of 1997-2007. In water depths ranging from 36-48 m, there were 4-9 mobility events/year of 1-2 days duration. Integrated wave stress during events (IWAVES) was used as a combined metric of wave-driven mobility intensity and duration. In the MAB, over 67% of IWAVES was caused by extratropical storms, while in the SAB, greater than 66% of IWAVES was caused by tropical storms. On average, mobility events were caused by waves generated by storms located 800+ km away. Far-field hurricanes generated swell 2-4 days before the waves caused mobility on the shelf. Throughout most of the SAB, mobility events were driven by storms to the south, east, and west. In the MAB and near Cape Hatteras, winds from more northerly storms and low-pressure extratropical systems in the mid-western U.S. also drove mobility events. Waves generated by storms off the SAB generated mobility events along the entire U.S. East Coast shelf north to Cape Cod, while Cape Hatteras shielded the SAB area from swell originating to the north offshore of the MAB.

  14. Structure, transport, and vertical coherence of the Gulf Stream from the Straits of Florida to the Southeast Newfoundland Ridge

    NASA Astrophysics Data System (ADS)

    Meinen, Christopher S.; Luther, Douglas S.

    2016-05-01

    Data from three independent and extensive field programs in the Straits of Florida, the Mid-Atlantic Bight, and near the Southeast Newfoundland Ridge are reanalyzed and compared with results from other historical studies to highlight the downstream evolution of several characteristics of the Gulf Stream's mean flow and variability. The three locations represent distinct dynamical regimes: a tightly confined jet in a channel; a freely meandering jet; and a topographically controlled jet on a boundary. Despite these differing dynamical regimes, the Gulf Stream in these areas exhibits many similarities. There are also anticipated and important differences, such as the loss of the warm core of the current by 42°N and the decrease in the cross-frontal gradient of potential vorticity as the current flows northward. As the Gulf Stream evolves it undergoes major changes in transport, both in magnitude and structure. The rate of inflow up to 60°W and outflow thereafter are generally uniform, but do exhibit some remarkable short-scale variations. As the Gulf Stream flows northward the vertical coherence of the flow changes, with the Florida Current and North Atlantic Current segments of the Gulf Stream exhibiting distinct upper and deep flows that are incoherent, while in the Mid-Atlantic Bight the Gulf Stream exhibits flows in three layers each of which tends to be incoherent with the other layers at most periods. These coherence characteristics are exhibited in both Eulerian and stream coordinates. The observed lack of vertical coherence indicates that great caution must be exercised in interpreting proxies for Gulf Stream structure and flow from vertically-limited or remote observations.

  15. Structure, transport, and vertical coherence of the Gulf Stream from the Straits of Florida to the Southeast Newfoundland Ridge

    NASA Astrophysics Data System (ADS)

    Meinen, Christopher S.; Luther, Douglas S.

    2016-06-01

    Data from three independent and extensive field programs in the Straits of Florida, the Mid-Atlantic Bight, and near the Southeast Newfoundland Ridge are reanalyzed and compared with results from other historical studies to highlight the downstream evolution of several characteristics of the Gulf Stream's mean flow and variability. The three locations represent distinct dynamical regimes: a tightly confined jet in a channel; a freely meandering jet; and a topographically controlled jet on a boundary. Despite these differing dynamical regimes, the Gulf Stream in these areas exhibits many similarities. There are also anticipated and important differences, such as the loss of the warm core of the current by 42°N and the decrease in the cross-frontal gradient of potential vorticity as the current flows northward. As the Gulf Stream evolves it undergoes major changes in transport, both in magnitude and structure. The rate of inflow up to 60°W and outflow thereafter are generally uniform, but do exhibit some remarkable short-scale variations. As the Gulf Stream flows northward the vertical coherence of the flow changes, with the Florida Current and North Atlantic Current segments of the Gulf Stream exhibiting distinct upper and deep flows that are incoherent, while in the Mid-Atlantic Bight the Gulf Stream exhibits flows in three layers each of which tends to be incoherent with the other layers at most periods. These coherence characteristics are exhibited in both Eulerian and stream coordinates. The observed lack of vertical coherence indicates that great caution must be exercised in interpreting proxies for Gulf Stream structure and flow from vertically-limited or remote observations.

  16. Final Technical Report: DOE-Biological Ocean Margins Program. Microbial Ecology of Denitrifying Bacteria in the Coastal Ocean.

    SciTech Connect

    Lee Kerkhof

    2013-01-01

    The focus of our research was to provide a comprehensive study of the bacterioplankton populations off the coast of New Jersey near the Rutgers University marine field station using terminal restriction fragment polymorphism analysis (TRFLP) coupled to 16S rRNA genes for large data set studies. Our three revised objectives to this study became: (1) to describe bacterioplankton population dynamics in the Mid Atlantic Bight using TRFLP analysis of 16S rRNA genes. (2) to determine whether spatial and temporal factors are driving bacterioplankton community dynamics in the MAB using monthly samping along our transect line over a 2-year period. (3) to identify dominant members of a coastal bacterioplankton population by clonal library analysis of 16S rDNA genes and sequencing of PCR product corresponding to specific TRFLP peaks in the data set. Although open ocean time-series sites have been areas of microbial research for years, relatively little was known about the population dynamics of bacterioplankton communities in the coastal ocean on kilometer spatial and seasonal temporal scales. To gain a better understanding of microbial community variability, monthly samples of bacterial biomass were collected in 1995-1996 along a 34-km transect near the Long-Term Ecosystem Observatory (LEO-15) off the New Jersey coast. Surface and bottom sampling was performed at seven stations along a transect line with depths ranging from 1 to 35m (n=178). The data revealed distinct temporal patterns among the bacterioplankton communities in the Mid-Atlantic Bight rather than grouping by sample location or depth (figure 2-next page). Principal components analysis models supported the temporal patterns. In addition, partial least squares regression modeling could not discern a significant correlation from traditional oceanographic physical and phytoplankton nutrient parameters on overall bacterial community variability patterns at LEO-15. These results suggest factors not traditionally

  17. Hydrocarbon potential of basins along Australia's southern margin

    SciTech Connect

    Willink, R.J. )

    1991-03-01

    Seven discrete sedimentary basins are recognized along the southern margin of the Australian continent; namely, from east to west, the Gippsland, Bass, Sorell, Otway, Duntroon, Bight, and Bremer. All formed since the Late Jurassic in response to the separation of Australia and Antarctica, and to the opening of the Tasman Sea. Only the Gippsland basin, which has proved initial oil reserves exceeding 3.6 billion barrels, is a prolific oil province. The search for oil in the other basins has been virtually fruitless despite many similarities between these basins and the Gippsland in terms of stratigraphy and structural geology. Rift and drift components are discernible in the sedimentary successions of all basins but the precise tectonic controls on respective basin formation remain conjectural. The lack of drilling success in the Bremer, Bight, Duntroon, Otway, and Sorell basins has been attributed mainly to the paucity of mature, oil-prone source rocks. The common occurrence of stranded bitumens along the entire coastline, however, indicates oil generation. The Bass and Gippsland basins are both characterized by excellent oil-prone source rocks developed in Late Cretaceous to Early Tertiary sediments. Limited exploration success in the Bass basin is due to poorer reservoir development. The Gippsland basin is at a mature stage of exploration whereas the other basins are moderately to very sparsely explored. Consequently, there is a comparable potential for undiscovered hydrocarbons in all basins. Success in the under-explored basins will come only to those prepared to challenge the perception of low prospectivity. Many play types remain to be tested by the drill.

  18. The distribution, diversity, and importance of cephalopods in top predator diets from offshore habitats of the Northwest Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Staudinger, M. D.; Juanes, F.; Salmon, B.; Teffer, A. K.

    2013-10-01

    Large pelagic predators were used as biological samplers to gain information on cephalopod diversity, abundance, distribution, and their role as prey in the Northwest Atlantic Ocean. Fish predators were caught by recreational anglers in offshore waters of New England (NE; 2007-2010), the Mid-Atlantic Bight (MAB; 2009-2010) and the South Atlantic Bight (SAB; 2010-2011). In total, 2362 cephalopods, including 22 species of squid and 4 octopods, were identified in the diets of 13 species of predatory fishes. Cephalopod body sizes were obtained for 1973 specimens through direct measurement of mantle lengths (ML) or estimated using lower rostral/hood lengths of lower beaks. Cephalopod diversity (number of species) was highest in predator diets from the SAB (N=19), intermediate in NE (N=18), and lowest in the MAB (N=9); however, differences may reflect unequal sampling effort among regions. The most important cephalopods across predator diets by number and frequency of occurrence were from the families Ommastrephidae, Argonautidae, Loliginidae, and Histioteuthidae. Shortfin squid (Illex illecebrosus) and paper nautilus (Argonauta sp.) were the most recurrent species identified across spatiotemporal scales; size distributions of these two species varied significantly among regions, and the largest individuals on average were found in the MAB. Results demonstrate that although pelagic predators consumed a broad range of cephalopod species, octopods and squids from the families Argonautidae and Ommastrephidae dominated the collective diets of numerous pelagic teleosts and elasmobranchs, and play a key role in offshore food-webs of the Northwest Atlantic Ocean. This study emphasizes the value of using predators as biological samplers to gain information on cephalopod biogeography, and as a potential approach to track ecosystem changes in this region due to environmental and anthropogenic stressors.

  19. Impact of climate change on freshwater resources in a heterogeneous coastal aquifer of Bremerhaven, Germany: A three-dimensional modeling study.

    PubMed

    Yang, Jie; Graf, Thomas; Ptak, Thomas

    2015-01-01

    Climate change is expected to induce sea level rise in the German Bight, which is part of the North Sea, Germany. Climate change may also modify river discharge of the river Weser flowing into the German Bight, which will alter both pressure and salinity distributions in the river Weser estuary. To study the long-term interaction between sea level rise, discharge variations, a storm surge and coastal aquifer flow dynamics, a 3D seawater intrusion model was designed using the fully coupled surface-subsurface numerical model HydroGeoSphere. The model simulates the coastal aquifer as an integral system considering complexities such as variable-density flow, variably saturated flow, irregular boundary conditions, irregular land surface and anthropogenic structures (e.g., dyke, drainage canals, water gates). The simulated steady-state groundwater flow of the year 2009 is calibrated using PEST. In addition, four climate change scenarios are simulated based on the calibrated model: (i) sea level rise of 1m, (ii) the salinity of the seaside boundary increases by 4 PSU (Practical Salinity Units), (iii) the salinity of the seaside boundary decreases by 12 PSU, and (iv) a storm surge with partial dyke failure. Under scenarios (i) and (iv), the salinized area expands several kilometers further inland during several years. Natural remediation can take up to 20 years. However, sudden short-term salinity changes in the river Weser estuary do not influence the salinized area in the coastal aquifer. The obtained results are useful for coastal engineering practices and drinking water resource management.

  20. Surface Ocean pCO2 Seasonality and Sea-Air CO2 Flux Estimates for the North American East Coast

    NASA Technical Reports Server (NTRS)

    Signorini, Sergio; Mannino, Antonio; Najjar, Raymond G., Jr.; Friedrichs, Marjorie A. M.; Cai, Wei-Jun; Salisbury, Joe; Wang, Zhaohui Aleck; Thomas, Helmuth; Shadwick, Elizabeth

    2013-01-01

    Underway and in situ observations of surface ocean pCO2, combined with satellite data, were used to develop pCO2 regional algorithms to analyze the seasonal and interannual variability of surface ocean pCO2 and sea-air CO2 flux for five physically and biologically distinct regions of the eastern North American continental shelf: the South Atlantic Bight (SAB), the Mid-Atlantic Bight (MAB), the Gulf of Maine (GoM), Nantucket Shoals and Georges Bank (NS+GB), and the Scotian Shelf (SS). Temperature and dissolved inorganic carbon variability are the most influential factors driving the seasonality of pCO2. Estimates of the sea-air CO2 flux were derived from the available pCO2 data, as well as from the pCO2 reconstructed by the algorithm. Two different gas exchange parameterizations were used. The SS, GB+NS, MAB, and SAB regions are net sinks of atmospheric CO2 while the GoM is a weak source. The estimates vary depending on the use of surface ocean pCO2 from the data or algorithm, as well as with the use of the two different gas exchange parameterizations. Most of the regional estimates are in general agreement with previous studies when the range of uncertainty and interannual variability are taken into account. According to the algorithm, the average annual uptake of atmospheric CO2 by eastern North American continental shelf waters is found to be between 3.4 and 5.4 Tg C/yr (areal average of 0.7 to 1.0 mol CO2 /sq m/yr) over the period 2003-2010.

  1. Impact of climate change on freshwater resources in a heterogeneous coastal aquifer of Bremerhaven, Germany: A three-dimensional modeling study

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Graf, Thomas; Ptak, Thomas

    2015-06-01

    Climate change is expected to induce sea level rise in the German Bight, which is part of the North Sea, Germany. Climate change may also modify river discharge of the river Weser flowing into the German Bight, which will alter both pressure and salinity distributions in the river Weser estuary. To study the long-term interaction between sea level rise, discharge variations, a storm surge and coastal aquifer flow dynamics, a 3D seawater intrusion model was designed using the fully coupled surface-subsurface numerical model HydroGeoSphere. The model simulates the coastal aquifer as an integral system considering complexities such as variable-density flow, variably saturated flow, irregular boundary conditions, irregular land surface and anthropogenic structures (e.g., dyke, drainage canals, water gates). The simulated steady-state groundwater flow of the year 2009 is calibrated using PEST. In addition, four climate change scenarios are simulated based on the calibrated model: (i) sea level rise of 1 m, (ii) the salinity of the seaside boundary increases by 4 PSU (Practical Salinity Units), (iii) the salinity of the seaside boundary decreases by 12 PSU, and (iv) a storm surge with partial dyke failure. Under scenarios (i) and (iv), the salinized area expands several kilometers further inland during several years. Natural remediation can take up to 20 years. However, sudden short-term salinity changes in the river Weser estuary do not influence the salinized area in the coastal aquifer. The obtained results are useful for coastal engineering practices and drinking water resource management.

  2. Long-term trends and variability in the larvae of Pacific sardine and associated fish species of the California Current region

    NASA Astrophysics Data System (ADS)

    Smith, Paul E.; Moser, H. Geoffrey

    2003-08-01

    Fifty-year ichthyoplankton and oceanographic time series of the California Cooperative Oceanic Fisheries Investigations were used to describe changes in larval fish abundance and associated habitat features in the Southern California Bight region, extending seaward to the limits of the California Current. The ichthyoplankton data set for this analysis was based on single tows taken at all CalCOFI survey stations occupied within the current sampling pattern from 1951 to 2000 and consisted of a total of 11,917 samples from which 1,365,988 fish larvae were identified. The analysis included data on habitat temperature, macrozooplankton volumes, and 14 taxa of larval fishes, some of commercial interest (Pacific sardine, Pacific hake, Pacific and jack mackerel, and rockfishes), and a group of important mesopelagic species that represent specific habitats in the California Current region. Data are presented in a series of graphs showing changes in average abundance, triennial abundance ratios, and normalized quarterly abundance (1988-2000 only). Larval data clearly track the decline and recovery of the Pacific sardine population. Mesopelagic larvae of southern offshore species had the greatest response to the regime shift of 1976-77, increasing markedly in the Southern California Bight region after 1977. Likewise, this group of species showed the greatest response to the 1957-59 El Niño. There was no consistent response in larval abundance of Subarctic-Transitional mesopelagic species and nearshore taxa to the 1976-77 regime shift. Most of the species showed a negative shift in triennial larval abundance ratios in relation to hypothesized 1989-90 and 1998-99 regime shifts. These changes are discussed in relation to changes in temperature and macrozooplankton volumes.

  3. Retention of crab larvae in a coastal null zone

    NASA Astrophysics Data System (ADS)

    Tilburg, Charles E.; Dittel, Ana I.; Epifanio, Charles E.

    2007-05-01

    Alongshelf transport in the southern Middle Atlantic Bight is forced by buoyancy-driven currents originating in three large estuaries along the bight. These currents are strongest in the coastal ocean near the southern terminus of each estuary, while the analogous region on the northern side is characterized by weak subtidal flow. We used a combination of field observations and numerical modeling to test the hypothesis that these regions of weak subtidal flow are coastal null zones that serve as retention areas for larvae. The field study consisted of a four-day, shipboard investigation of the distribution of blue crab larvae ( Callinectes sapidus) near the mouth of Delaware Bay (˜39°N, 75°W) in late summer, 2004. Hydrographic surveys of the study site were conducted with a hull-mounted, surface-measuring system. Results showed a sharp boundary between the null zone and the buoyancy-driven current to the south. Blue crab larvae were collected in surface plankton tows along a 30-km transect that encompassed these two areas. Stations with higher densities of larvae were clustered in the null zone during both ebb and flood tides. A numerical model was used to examine the physical mechanisms responsible for the observed distribution. Model results agreed with the field survey and showed that simulated larvae are aggregated in the null zone. The simulations also demonstrated that larvae spawned within the null zone have a much greater probability of settling in juvenile nursery habitat within the bay. The close agreement between field and model results provides consistent support for the hypothesis that coastal null zones associated with the buoyancy-driven circulation of large estuaries may allow retention of larvae in the vicinity of the natal spawning population.

  4. The Carbon Budget of Coastal Waters of Eastern North America

    NASA Astrophysics Data System (ADS)

    Najjar, R.; Boyer, E. W.; Burdige, D.; Butman, D. E.; Cai, W. J.; Canuel, E. A.; Chen, R. F.; Friedrichs, M. A.; Griffith, P. C.; Herrmann, M.; Kemp, W. M.; Kroeger, K. D.; Mannino, A.; McCallister, S. L.; McGillis, W. R.; Mulholland, M. R.; Salisbury, J.; Signorini, S. R.; Tian, H.; Tzortziou, M.; Vlahos, P.; Wang, A. Z.; Zimmerman, R. C.; Pilskaln, C. H.

    2015-12-01

    Observations and the output of numerical and statistical models are synthesized to construct a carbon budget of the coastal waters of eastern North America. The domain extends from the head of tide to (roughly) the continental shelf break and from southern Florida to southern Nova Scotia. The domain area is 2% tidal wetlands, 19% estuarine open water, and 78% shelf water. Separate budgets are constructed for inorganic and organic carbon; for tidal wetlands, estuaries, and shelf waters; and for three main subregions: the Gulf of Maine, the Mid-Atlantic Bight, and the South Atlantic Bight. Net primary production for the study region is about 150 Tg C yr-1, with 12% occurring in tidal wetlands and 7% in estuaries. Though respiration and photosynthesis are nearly balanced in most systems and regions, tidal wetlands and shelf waters are each found to be net autotrophic whereas estuaries are net heterotrophic. The domain as a whole is a sink of 5 Tg C yr-1 of atmospheric CO2, with tidal wetlands and shelf waters taking up 10 Tg C yr-1 (split roughly equally) and estuaries releasing 5 Tg C yr-1 to the atmosphere. Carbon burial is about 3 Tg C yr-1, split roughly equally among tidal wetlands, estuaries, and shelf waters. Rivers supply 6-7 Tg C yr-1 to estuaries, about 2/3 of which is organic. Tidal wetlands supply an additional 4 Tg C yr-1 to estuaries, about half of which is organic. Carbon in organic and inorganic forms is exported from estuaries to shelf waters and from shelf waters to the open ocean. In summary, tidal wetlands and estuaries, though small in area, contribute substantially to the overall carbon budget of the region.

  5. Initiation and intensification of east Pacific easterly waves

    NASA Astrophysics Data System (ADS)

    Rydbeck, Adam V.

    are, at times, associated with very weak EW convection anomalies due to weaker moisture and diluted CAPE variations. The in-situ generation of EWs in the EPAC is then investigated using the Weather Research and Forecasting Model (WRF). Sensitivity tests are performed to examine the atmospheric response to the removal of external and internal EW forcing in the EPAC warm pool. External forcing of EPAC EWs is removed by filtering EWs in wavenumber frequency space from the model's boundary forcing. Internal forcing of EWs is removed by reducing the terrain height in portions of Central and South America to suppress the strong source of diurnal convective variability in the Panama Bight. These regions of high terrain are associated with mesoscale convective systems that routinely initiate in the early morning and propagate westward into the EPAC warm pool. In both sensitivity tests, EW variance is significantly reduced in the EPAC, suggesting that both EWs propagating into the EPAC from the east and EWs generated locally in association with higher frequency convective disturbances are critical to EPAC EW variability. A new mechanism is proposed to explain the in-situ generation of EPAC EWs. Serial mid-level diurnal vorticity and divergence anomalies generated in association with deep convection originating in the Panama Bight underpin the local generation, intensification, and spatial scale selection of EW vorticity by vertical vorticity stretching. Diurnal vorticity anomalies in the Panama Bight are able to initiate disturbances capable of growing into robust EWs through a tendency to organize vorticity upscale.

  6. Comparison of aliphatic hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polybrominated diphenylethers, and organochlorine pesticides in Pacific sanddab (Citharichthys sordidus) from offshore oil platforms and natural reefs along the California coast

    USGS Publications Warehouse

    Gale, Robert W.; Tanner, Michael J.; Love, Milton S.; Nishimoto, Mary M.; Schroeder, Donna M.

    2013-01-01

    Recently, the relative exposure of Pacific sanddab (Citharichthys sordidus) to polycyclic aromatic hydrocarbons (PAHs) at oil-production platforms was reported, indicating negligible exposure to PAHs and no discernible differences between exposures at platforms and nearby natural areas sites. In this report, the potential for chronic PAH exposure in fish is reported, by measurement of recalcitrant, higher molecular weight PAHs in tissues of fish previously investigated for PAH metabolites in bile. A total of 34 PAHs (20 PAHs, 11 alkylated PAHs, and 3 polycyclic aromatic thiophenes) were targeted. In addition, legacy contaminants—polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs),—and current contaminants, polybrominated diphenylethers (PBDEs) linked to endocrine disruption, were measured by gas chromatography with electron-capture or mass spectrometric detection, to form a more complete picture of the contaminant-related status of fishes at oil production platforms in the Southern California Bight. No hydrocarbon profiles or unresolved complex hydrocarbon background were found in fish from platforms and from natural areas, and concentrations of aliphatics were low less than 100 nanograms per gram (ng/g) per component]. Total-PAH concentrations in fish ranged from 15 to 37 ng/g at natural areas and from 8.7 to 22 ng/g at platforms. Profiles of PAHs were similar at all natural and platform sites, consisting mainly of naphthalene and methylnaphthalenes, phenanthrene, fluoranthene, and pyrene. Total-PCB concentrations (excluding non-ortho-chloro-substituted congeners) in fish were low, ranging from 7 to 22 ng/g at natural areas and from 10 to 35 ng/g at platforms. About 50 percent of the total-PCBs at all sites consisted of 11 congeners: 153 > 138/163/164 > 110 > 118 > 15 > 99 > 187 > 149 > 180. Most OCPs, except dichlorodiphenyltrichloroethane (DDT)-related compounds, were not detectable or were at concentrations of less than 1 ng/g in fish. p

  7. Salinity variability along the eastern continental shelf of Canada and the United States, 1973-2013

    NASA Astrophysics Data System (ADS)

    Bisagni, James J.

    2016-09-01

    Continental shelf waters located off the east coast of Canada and the United States are part of a long shelf current system that is partly comprised of colder, less-saline waters originating from high latitudes, including waters from the North Atlantic sub-polar gyre, along with ice-melt and freshwater input from local rivers. A 41-year analysis (1973-2013) of near-surface salinity (NSS) using three hydrographic datasets (Bedford Institute of Oceanography "Climate", NOAA/ESDIM, and Canadian Marine Environmental Data Service (MEDS)) allowed an examination of NSS variability within 11 continental shelf sub-regions, extending from the southern Newfoundland Shelf of eastern Canada to the DelMarVa/Hatteras Shelf of the United States. Although the periods of record containing sufficient data vary between sub-regions, regional mean NSS values are lowest within the Gulf of St. Lawrence and highest on the DelMarVa/Hatteras shelf, with largest annual variability within the Gulf of St. Lawrence. After removal of outliers, long-term linear trends computed from annual mean NSS were detected along the Newfoundland Shelf (+0.011 y-1), Western Scotian Shelf (-0.007 y-1), Gulf of Maine (-0.014 y-1), Georges Bank (-0.011 y-1), and DelMarVa/Hatteras Shelf (+0.024 y-1). A long-term quadratic fit to annual mean NSS from the Eastern Scotian Shelf displays a salinity increase through 1992 of +0.026 y-1, decreasing thereafter until 2013 by -0.028 y-1. A quadratic fit for the Western Grand Banks displays a NSS increase through 2007 of +0.022 y-1, decreasing thereafter through 2013 by -0.006 y-1. Annual mean NSS from the Eastern Grand Banks, Tail of the Grand Banks, Gulf of St. Lawrence, and Middle Atlantic Bight display no long-term trends. Inter-annual variability (IAV) of NSS residuals shows similar small mean squared error (mse) of 0.02-0.04 for the four northern-most sub-regions (Newfoundland Shelf, Eastern, Tail and Western Grand Banks) and are correlated at 0-year lag. IAV of NSS

  8. Marine habitat mapping, classification and monitoring in the coastal North Sea: Scientific vs. stakeholder interests

    NASA Astrophysics Data System (ADS)

    Hass, H. Christian; Mielck, Finn; Papenmeier, Svenja; Fiorentino, Dario

    2016-04-01

    Producing detailed maps of the seafloor that include both, water depth and simple textural characteristics has always been a challenge to scientists. In this context, marine habitat maps are an essential tool to comprehend the complexity, the spatial distribution and the ecological status of different seafloor types. The increasing need for more detail demands additional information on the texture of the sediment, bedforms and information on benthic sessile life. For long time, taking samples and videos/photographs followed by interpolation over larger distances was the only feasible way to gain information about sedimentary features such as grain-size distribution and bedforms. While ground truthing is still necessary, swath systems such as multibeam echo sounders (MBES) and sidescan sonars (SSS), as well as single beam acoustic ground discrimination systems (AGDS) became available to map the seafloor area-wide (MBES, SSS), fast and in great detail. Where area-wide measurements are impossible or unavailable point measurements are interpolated, classified and modeled. To keep pace with environmental change in the highly dynamic coastal areas of the North Sea (here: German Bight) monitoring that utilizes all of the mentioned techniques is a necessity. Since monitoring of larger areas is quite expensive, concepts for monitoring strategies were developed in scientific projects such as "WIMO" ("Scientific monitoring concepts for the German Bight, SE North Sea"). While instrumentation becomes better and better and interdisciplinary methods are being developed, the gap between basic scientific interests and stakeholder needs often seem to move in opposite directions. There are two main tendencies: the need to better understand nature systems (for theoretical purposes) and the one to simplify nature (for applied purposes). Science trends to resolve the most detail in highest precision employing soft gradients and/or fuzzy borders instead of crisp demarcations and

  9. Observed Response of the Hudson River Plume to Wind Forcing

    NASA Astrophysics Data System (ADS)

    Glenn, S.; Schofield, O.; Chant, R.; Kohut, J.

    2004-12-01

    One objective of the May 2004 pilot study for the Lagrangian Transport and Transformation Experiment (LaTTE) was to determine the relative advantages of studying the Hudson River plume within the spatial and temporal context provided by a research-friendly coastal ocean observatory. Towards this end, a shelf-wide observational backbone was locally enhanced with high-resolution relocatable systems in the New York Bight apex. The permanent backbone includes local acquisition of international satellite ocean color imagery, a network of long-range High Frequency radars, and a cross-shelf Endurance line occupied by an autonomous underwater glider. The higher resolution HF Radar, glider and mooring network was originally deployed in the vicinity of the Long-term Ecosystem Observatory, where it attracted a large number of scientists to coastal upwelling experiments conducted offshore Tuckerton, NJ from 1998-2001. With scientific interest in the series of coastal upwelling experiments having peaked and run its course through the publication phase, the high resolution systems were moved to the New York Bight Apex to hopefully repeat the cycle of attracting a variety of scientists to a specific interdisciplinary process study site. During the LaTTE pilot study, datasets from the nested observation network were assembled in real-time at a shore-based acquisition center, and high-resolution atmospheric forecasts were performed. Specific emphasis was placed on communicating the real time observatory data and forecasts to scientists on a pair of research vessels conducting a dye release with the associated physical, biological and chemical sampling. Observational results from the observatory will be reviewed, with specific emphasis placed on the observed response of the Hudson River plume to a windshift from upwelling to downwelling favorable winds in the middle of the pilot experiment. This includes a shift from a relatively weak plume flowing eastward along the south shore of

  10. Inner-shelf ocean dynamics and seafloor morphologic changes during Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Warner, John C.; Schwab, William C.; List, Jeffrey H.; Safak, Ilgar; Liste, Maria; Baldwin, Wayne

    2017-04-01

    Hurricane Sandy was one of the most destructive hurricanes in US history, making landfall on the New Jersey coast on October 30, 2012. Storm impacts included several barrier island breaches, massive coastal erosion, and flooding. While changes to the subaerial landscape are relatively easily observed, storm-induced changes to the adjacent shoreface and inner continental shelf are more difficult to evaluate. These regions provide a framework for the coastal zone, are important for navigation, aggregate resources, marine ecosystems, and coastal evolution. Here we provide unprecedented perspective regarding regional inner continental shelf sediment dynamics based on both observations and numerical modeling over time scales associated with these types of large storm events. Oceanographic conditions and seafloor morphologic changes are evaluated using both a coupled atmospheric-ocean-wave-sediment numerical modeling system that covered spatial scales ranging from the entire US east coast (1000 s of km) to local domains (10 s of km). Additionally, the modeled response for the region offshore of Fire Island, NY was compared to observational analysis from a series of geologic surveys from that location. The geologic investigations conducted in 2011 and 2014 revealed lateral movement of sedimentary structures of distances up to 450 m and in water depths up to 30 m, and vertical changes in sediment thickness greater than 1 m in some locations. The modeling investigations utilize a system with grid refinement designed to simulate oceanographic conditions with progressively increasing resolutions for the entire US East Coast (5-km grid), the New York Bight (700-m grid), and offshore of Fire Island, NY (100-m grid), allowing larger scale dynamics to drive smaller scale coastal changes. Model results in the New York Bight identify maximum storm surge of up to 3 m, surface currents on the order of 2 ms-1 along the New Jersey coast, waves up to 8 m in height, and bottom stresses

  11. Meteo-Marine Parameters from High-Resolution Satellite-Based Radar Measurements and Impact of Wind Gusts on local Sea State Variability

    NASA Astrophysics Data System (ADS)

    Pleskachevsky, Andrey; Lehner, Susanne; Rosenthal, Wolfgang

    2016-04-01

    To investigate local geophysical processes, sea surface wind speed and the sea state field simultaneously estimated from X-band satellite-borne Synthetic Aperture Radar (SAR) images acquired over North Sea were compared and analysed. The data were retrieved from TerraSAR-X (TS-X) satellite scenes with overflight covering ~300km×30km with resolution of 3m. The inhomogeneity of wind fields and the impact of wind gust systems on the local sea state are studied based on space-covered remote sensing data and in-situ buoy measurements in the German Bight of the North Sea. The sea state parameters and wind speed were estimated using newly developed Sea State Processor (SSP)for meteo-marine parameter estimation. The SSP is designed for supporting forecast services and providing validation in coastal areas with robust automatic space-covering processing in near real time (NRT). SSP includes a pre-filtering procedure for removing artefacts like ships, seamarks, buoys, offshore constructions and slicks from analysed images, the empirical XWAVEC (C=Coastal) algorithm developed for coastal seas for estimation significant wave height, XMOD-2 wind algorithm and an additional procedure performing a control of results based on the statistics of the whole scene. The collected, processed and analysed data base for the German Bight consists of more than 60 TS-X StripMap scenes/overflights with more than 200 images acquired since 2013. The acquired conditions vary in range 0-7m for significant wave height and in range 0-25m/s of the surface wind speed. The spatial comparison of sea state and wind field estimated form remote sensing data to the results of the wave prediction models show local variations due to distinctions in bathymetry and in wind front propagation. At the first time it was observed and registered: the local wave height increase of 1-2m is connected to wind gusts in kilometre-scale clusters. The statistical analysis allows to connect the typical weather conditions

  12. Using Darwin's theory of atoll formation to improve tsunami hazard mitigation in the Pacific

    NASA Astrophysics Data System (ADS)

    Goff, J. R.; Terry, J. P.

    2012-12-01

    It is 130 years since Charles Darwin's death and 176 years since he his penned his subsidence theory of atoll formation on 12th April 1836 during the voyage of the Beagle through the Pacific. This theory, founded on the premise of a subsiding volcano and the corresponding upward growth of coral reef, was astonishing for the time considering the absence of an underpinning awareness of plate tectonics. Furthermore, with the exception of the occasional permutation and opposing idea his theory has endured and has an enviable longevity amongst paradigms in geomorphology. In his theory, Darwin emphasised the generally circular morphology of the atoll shape and surprisingly, the validity of this simple morphological premise has never been questioned. There are however, few atolls in the Pacific Ocean that attain such a simple morphology with most manifesting one or more arcuate 'bight-like' structures (ABLSs). These departures from the circular form complicate his simplistic model and are indicative of geomorphological processes in the Pacific Ocean which cannot be ignored. ABLSs represent the surface morphological expression of major submarine failures of atoll volcanic foundations. Such failures can occur during any stage of atoll formation and are a valuable addition to Darwin's theory because they indicate the instability of the volcanic foundations. It is widely recognized in the research community that sector/flank collapses of island edifices are invariably tsunamigenic and yet we have no clear understanding of how significant such events are in the tsunami hazard arena. The recognition of ABLSs however, now offers scientists the opportunity to establish a first order database of potential local and regional tsunamigenic sources associated with the sector/flank collapses of island edifices. We illustrate the talk with examples of arcuate 'bight-like' structures and associated tsunamis in atoll and atoll-like environments. The implications for our understanding of

  13. Relative impact of seasonal and oceanographic drivers on surface chlorophyll a along a Western Boundary Current

    NASA Astrophysics Data System (ADS)

    Everett, Jason D.; Baird, Mark E.; Roughan, Moninya; Suthers, Iain M.; Doblin, Martina A.

    2014-01-01

    Strengthening Western Boundary Currents (WBCs) advect warm, low nutrient waters into temperate latitudes, displacing more productive waters. WBCs also influence phytoplankton distribution and growth through current-induced upwelling, mesoscale eddy intrusion and seasonal changes in strength and poleward penetration. Here we examine dynamics of chlorophyll a (Chl. a) in the western Pacific Ocean, a region strongly influenced by the East Australian Current (EAC). We interpreted a spatial and temporal analysis of satellite-derived surface Chl. a, using a hydrodynamic model, a wind-reanalysis product and an altimetry-derived eddy-census. Our analysis revealed regions of persistently elevated surface Chl. a along the continental shelf and showed that different processes have a dominant effect in different locations. In the northern and central zones, upwelling events tend to regulate surface Chl. a patterns, with peaks in phytoplankton biomass corresponding to two known upwelling locations south of Cape Byron (28.5°S) and Smoky Cape (31°S). Within the central EAC separation zone, positive surface Chl. a anomalies occurred 65% of the time when both wind-stress (τw) and bottom-stress (τB) were upwelling-favourable, and only 17% of the time when both were downwelling-favourable. The interaction of wind and the EAC was a critical driver of surface Chl. a dynamics, with upwelling-favourable τW resulting in a 70% increase in surface Chl. a at some locations, when compared to downwelling-favourable τW . In the southern zone, surface Chl. a was driven by a strong seasonal cycle, with phytoplankton biomass increasing up to 152% annually each spring. The Stockton Bight region (32.25-33.25°S) contained ⩾20% of the total shelf Chl. a on 27% of occasions due to its location downstream of upwelling locations, wide shelf area and reduced surface velocities. This region is analogous to productive fisheries regions in the Aghulus Current (Natal Bight) and Kuroshio Current

  14. Hydrogen Biogeochemistry in Anaerobic and Photosynthetic Ecosystems

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The simple biochemistry of molecular hydrogen is central to a large number of microbial processes, affecting the interaction of organisms with each other and with the environment. In anoxic sediments, a great majority of microbial redox processes involve hydrogen as a reactant, product or potential by-product. Accordingly, the energetics (thermodynamics) of each of these processes is affected by variations in local H2 concentrations. It has long been established that this effect is important in governing microbe-microbe interactions and there are multiple demonstrations that "interspecies hydrogen transfer" can alter the products of, inhibit/stimulate, or even reverse microbial metabolic reactions. In anoxic sediments, H2 concentrations themselves are thought to be controlled by the thermodynamics of the predominant H2-consuming microbial process. In sediments from Cape Lookout Bight, this relationship quantitatively describes the co-variation of H2 concentrations with temperature (for methanogens and sulfate reducers) and with sulfate concentration (for sulfate reducers). The quantitative aspect is import= for two reasons: 1) it permits the modeling of H2-sensitive biogeochemistry, such as anaerobic methane oxidation or pathways of organic matter remineralization, as a function of environmental controls; 2) for such a relationship to be observed requires that intracellular biochemistry and bioenergetics are being directly expressed in a component of the extracellular medium. H2 could therefore be utilized a non-invasive probe of cellular energetic function in intact microbial ecosystems. Based on the latter principle we have measured down-core profiles of H2 and other relevant physico-chemical parameters in order to calculate the metabolic energy yields (DG) that support microbial metabolism in Cape Lookout Bight sediments. Methanogens in this system apparently function with energy yields significantly smaller than the minimum requirements suggested by pure

  15. Mercury species in dab (Limanda limanda) from the North Sea, Baltic Sea and Icelandic waters in relation to host-specific variables.

    PubMed

    Lang, Thomas; Kruse, Reinhard; Haarich, Michael; Wosniok, Werner

    2017-03-01

    In the framework of the ICON project (Integrated Assessment of Contaminant Impacts on the North Sea), muscle tissue from a total of 135 common dab (Limanda limanda) (20-28 cm total length) was collected in seven offshore sampling areas in the North Sea, at Iceland and in the Baltic Sea during Aug/Sept and December 2008 for a chemical mercury speciation analysis by means of gas chromatography and detection by cold vapour atomic fluorescence spectroscopy (GC-CVAFS). There was a highly significant correlation between concentrations of methylmercury (MeHg(+)) and inorganic mercury (Hg(2+)) in individual fish, and the mean ratio of MeHg(+) compared to Σ Hg (MeHg(+) + Hg(2+)) was 94.0%. The results revealed statistically significant differences in concentrations of MeHg(+) and Hg(2+), respectively, between sampling areas. Mean concentrations in the German Bight (North Sea), in Icelandic waters and in Mecklenburg Bight (Baltic Sea) were low (MeHg(+): 0.023-0.036; Hg(2+): 0.001-0.002 mg/kg wet weight), while concentrations in dab from the Dogger Bank, Firth of Forth and the vicinity of the Ekofisk oil field (all North Sea) were significantly higher (MeHg(+): 0.059-0.101; Hg(2+): 0.003-0.004 mg/kg wet weight). Statistical correlation analysis on effects of host-specific factors revealed that neither length, weight, age, sex nor condition factor showed a significant relationship with Hg concentrations. However, Hg concentrations were significantly correlated with the Fish Disease Index (FDI), indicating a relationship between Hg concentrations and the health status of dab. Multiple linear regression analysis aiming to find factors affecting Hg concentrations revealed that only the sampling area had a highly significant main effect on Hg concentrations, and in some cases, additionally the condition factor contributed significantly to the final model. From the results, it cannot be excluded that elevated Hg concentration recorded in dab were linked to discharges from

  16. Hydrodynamic and Sediment Transport Processes in Long Bay of the Carolinas

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Xu, K.; He, R.; Wren, P. A.; Gong, Y.; Quigley, B.; Tarpley, D.

    2010-12-01

    The coastline along Long Bay of the Carolinas is a fast-growing and heavily-developed area supporting local populations, infrastructure, and a large tourism industry. Myrtle Beach and its adjacent sandy beaches are popular tourist destinations that attract millions of visitors each year, representing one of the state’s most essential natural resources. The economy of this region is closely related to the stability of the sandy beaches, which are vulnerable to coastal erosion during severe storm events. Quantifying the sediment transport processes in the nearshore and inner continental shelf regions is thus critical for both understanding the regional sediment budget and implementing effective coastal management. As a first step toward investigating the sediment transport processes, a three-dimensional coupled hydrodynamic-sediment transport model for Long Bay in the Carolinas has been developed. The model, based on the Regional Ocean Modeling System (ROMS), spans from Cape Fear estuary in NC to Winyah Bay estuary in SC. It considers the delivery of fluvial sediment from the Cape Fear and Pee Dee Rivers, resuspension from seabed, and transport of suspended sediment by ambient currents and waves calculated using Simulating WAve Nearshore model (SWAN). Our model simulations are driven by observed wind fields, which were collected at nearby meteorological stations maintained by National Data Buoy Center as well as at six buoys by the Palmetto Wind Research Project at Coastal Carolina University. Spatially varying sea bed conditions consisting of both hard bottoms and sandy bodies are applied in the calculation. The model is one-way nested inside a large-scale coastal circulation model that covers both the Middle Atlantic Bight and the South Atlantic Bight and provides dynamically consistent and numerically accurate circulation open boundary conditions. Modeling results indicate both wind-driven currents and storm-induced waves are capable of resuspending sandy

  17. The importance of gobies (Gobiidae, Teleostei) as hosts and transmitters of parasites in the SW Baltic

    NASA Astrophysics Data System (ADS)

    Zander, C. D.; Strohbach, U.; Groenewold, S.

    1993-02-01

    The parasite fauna of five goby species (Gobiidae, Teleostei) was investigated in the Baltic Sea during the period 1987 to 1990. 13 parasite species were found in samples from the Lübeck Bight: Bothriocephalus scorpii, Schistocephalus sp. (Cestoda); Cryptocotyle concavum, Cryptocotyle lingua, Podocotyle atomon, Derogenes varicus (Digenea); Hysterothylacium sp. (cf. auctum), Contracaecum sp., Anisakis simplex (Nematoda); Corynosoma sp., Echinorhynchus gadi, Neoechinorhynchus rutili, Pomphorhynchus laevis (Acanthocephala). The number of parasite species were: 10 in the sand goby Pomatoschistus minutus, 8 in the black goby Gobius niger, 7 in the two-spotted goby Gobiusculus flavescens, 6 in the common goby Pomatoschistus microps, and 5 in the painted goby Pomatoschistus pictus. Neoechinorhynchus rutili occurred only in P. minutus, and Corynosoma sp. only in G. niger. The extent to which the gobies were parasitized clearly depended on the respective ways of life and, moreover, on the kind of prey ingested by the hosts. Additionally, the age of the hosts might be important. The highest rate of parasitism, more than 60%, was reached by Hysterothylacium sp. in G. niger and by Cryptocotyle concavum in P. microps. Infestation incidence lay mostly below 40% which means a satellite species status (Holmes, 1991). The number of parasite species was highest in summer; the highest intensities of single parasites occurred in spring ( Podocotyle atomon) or autumn ( Crytocotyle concavum). Bothriocephalus scorpii, Hysterothylacium sp. and Podocotyle infested their juvenile hosts very early, but only Hysterothylacium was accumulated by G. niger during its whole life span, whereas Bothriocephalus persisted also in older gobies in low intensities. The cercariae of Cryptocotyle spp. penetrate actively into their hosts; all the other parasites named were transmitted in larval form by prey organisms which consisted mainly of planktonic and benthic crustaceans. The gobies were final hosts

  18. Epifauna dynamics at an offshore foundation--implications of future wind power farming in the North Sea.

    PubMed

    Krone, Roland; Gutow, Lars; Joschko, Tanja J; Schröder, Alexander

    2013-04-01

    In the light of the introduction of thousands of large offshore wind power foundations into the North Sea within the next decades, this manuscript focuses on the biofouling processes and likely reef effects. The study explores the macrozoobenthos (biofouling) colonization at an offshore platform which is comparable to offshore wind turbine foundations. A total of 183 single samples were taken and the parameters water depth and time were considered comparing biofouling masses and communities. The blue mussel Mytilus edulis, Anthozoa and the Amphipoda Jassa spp. were the dominant species. The community from the 1 m zone and those from the 5 and 20-28 m zones can clearly be differentiated. The 10 m zone community represents the transition between the M. edulis dominated 1 m and 5 m zones and the Anthozoa dominated 20-28 m zone. In the future offshore wind farms, thousands of wind turbine foundations will provide habitat for a hard bottom fauna which is otherwise restricted to the sparse rocky habitats scattered within extensive sedimentary soft bottoms of the German Bight. However, offshore wind power foundations cannot be considered natural rock equivalents as they selectively increase certain natural hard bottom species. The surface of the construction (1280 m²) was covered by an average of 4300 kg biomass. This foundation concentrates on its footprint area (1024 m²) 35 times more macrozoobenthos biomass than the same area of soft bottom in the German exclusive economic zone (0.12 kg m(-2)), functioning as a biomass hotspot. Concerning the temporal biomass variation, we assume that at least 2700 kg biomass was exported on a yearly basis. 345 × 10(4) single mussel shells of different sizes were produced during the study period. It is anticipated that the M. edulis abundance will increase in the North Sea due to the expansion of the offshore wind farm development. This will result in the enhanced production of secondary hard substrate (mussel shells

  19. Gulf Stream marine hydrokinetic energy resource characterization off Cape Hatteras, North Carolina

    NASA Astrophysics Data System (ADS)

    Muglia, M.; He, R.; Lowcher, C.; Bane, J.; Gong, Y.; Taylor, P.

    2015-12-01

    The Gulf Stream off North Carolina has current velocities that approach 3 m/s and an average volume transport of 90 Sv (1 Sv= 106 m3/s) off of Cape Hatteras, making it the most abundant MHK (Marine Hydrokinetic Energy) resource for the state. Resource availability at a specific location depends primarily on the variability in Gulf Stream position, which is least offshore of Cape Hatteras after the stream exits the Florida Straits. Proximity to land and high current velocities in relatively shallow waters on the shelf slope make this an optimal location to quantify the MHK energy resource for NC. 3.5 years of current measurements beginning in August of 2013 from a moored 150 kHz ADCP (Acoustic Doppler Current Profiler) at an optimal location for energy extraction quantify the available energy resource and its variability, and establish the skill of a Mid-Atlantic Bight and South Atlantic Bight Regional Ocean Model in predicting the MHK energy resource. The model agrees well with long-term observed current averages and with weekly to monthly fluctuations in the current speeds. Model and observations over the first 9 months of the ADCP deployment period both averaged 1.15 m/s thirty meters below the surface. The model under estimates observed current speeds for the higher frequency current fluctuations of days to weeks. Comparisons between the model and ADCP observed currents, and velocity derived power density over the entire 3.5 years of observations demonstrate the significant inter-annual variability in power density. Shipboard 300 kHz ADCP cross-stream transects and hourly surface currents measurements off Cape Hatteras from a network of land based HF (high frequency) radars further quantify available MHK energy and assess model skill. Cross-stream transects were made with a vessel-mounted 300 kHz ADCP on a line from the 100-1000m isobaths, and measured currents in the top 100m. These measurements demonstrate the variability in the resource with water depth, and

  20. Inner-shelf ocean dynamics and seafloor morphologic changes during Hurricane Sandy

    USGS Publications Warehouse

    Warner, John C.; Schwab, William C.; List, Jeffrey; Safak, Ilgar; Liste, Maria; Baldwin, Wayne E.

    2017-01-01

    Hurricane Sandy was one of the most destructive hurricanes in US history, making landfall on the New Jersey coast on Oct 30, 2012. Storm impacts included several barrier island breaches, massive coastal erosion, and flooding. While changes to the subaerial landscape are relatively easily observed, storm-induced changes to the adjacent shoreface and inner continental shelf are more difficult to evaluate. These regions provide a framework for the coastal zone, are important for navigation, aggregate resources, marine ecosystems, and coastal evolution. Here we provide unprecedented perspective regarding regional inner continental shelf sediment dynamics based on both observations and numerical modeling over time scales associated with these types of large storm events. Oceanographic conditions and seafloor morphologic changes are evaluated using both a coupled atmospheric-ocean-wave-sediment numerical modeling system and observation analysis from a series of geologic surveys and oceanographic instrument deployments focused on a region offshore of Fire Island, NY. The geologic investigations conducted in 2011 and 2014 revealed lateral movement of sedimentary structures of distances up to 450 m and in water depths up to 30 m, and vertical changes in sediment thickness greater than 1 m in some locations. The modeling investigations utilize a system with grid refinement designed to simulate oceanographic conditions with progressively increasing resolutions for the entire US East Coast (5-km grid), the New York Bight (700-m grid), and offshore of Fire Island, NY (100-m grid), allowing larger scale dynamics to drive smaller scale coastal changes. Model results in the New York Bight identify maximum storm surge of up to 3 m, surface currents on the order of 2 ms-1 along the New Jersey coast, waves up to 8 m in height, and bottom stresses exceeding 10 Pa. Flow down the Hudson Shelf Valley is shown to result in convergent sediment transport and deposition along its axis

  1. Sea-level rise impacts on the tides of the European Shelf

    NASA Astrophysics Data System (ADS)

    Idier, Déborah; Paris, François; Cozannet, Gonéri Le; Boulahya, Faiza; Dumas, Franck

    2017-04-01

    Sea-level rise (SLR) can modify not only total water levels, but also tidal dynamics. Several studies have investigated the effects of SLR on the tides of the western European continental shelf (mainly the M2 component). We further investigate this issue using a modelling-based approach, considering uniform SLR scenarios from -0.25 m to +10 m above present-day sea level. Assuming that coastal defenses are constructed along present-day shorelines, the patterns of change in high tide levels (annual maximum water level) are spatially similar, regardless of the magnitude of sea-level rise (i.e., the sign of the change remains the same, regardless of the SLR scenario) over most of the area (70%). Notable increases in high tide levels occur especially in the northern Irish Sea, the southern part of the North Sea and the German Bight, and decreases occur mainly in the western English Channel. These changes are generally proportional to SLR, as long as SLR remains smaller than 2 m. Depending on the location, they can account for +/-15% of regional SLR. High tide levels and the M2 component exhibit slightly different patterns. Analysis of the 12 largest tidal components highlights the need to take into account at least the M2, S2, N2, M4, MS4 and MN4 components when investigating the effects of SLR on tides. Changes in high tide levels are much less proportional to SLR when flooding is allowed, in particular in the German Bight. However, some areas (e.g., the English Channel) are not very sensitive to this option, meaning that the effects of SLR would be predictable in these areas, even if future coastal defense strategies are ignored. Physically, SLR-induced tidal changes result from the competition between reductions in bed friction damping, changes in resonance properties and increased reflection at the coast, i.e., local and non-local processes. A preliminary estimate of tidal changes by 2100 under a plausible non-uniform SLR scenario (using the RCP4.5 scenario) is

  2. Macrobenthos of the subtidal Wadden Sea: revisited after 55 years

    NASA Astrophysics Data System (ADS)

    Riesen, W.; Reise, K.

    1982-12-01

    During the years 1923 1926 Hagmeier & Kändler (1927) sampled the macrofauna of subtidal shallows and channels of the Wadden Sea close to the Island of Sylt (German Bight, North Sea). Reinvestigating this study area in 1980, a substantially altered faunal composition was recorded. An approach is made to quantify the comparison in terms of abundance, species richness and diversity of invertebrate taxa. Human interference is assumed to be responsible for the major changes. Natural oyster beds have been overexploited and the local population of Ostrea edulis has been driven to extinction. Subsequently, mussels (Mytilus edulis) spread in the entire region, promoted by shell fishery. Particularly barnacles and many polychaetes took advantage of the expansion of mussel banks which is substantiated by correlation analysis. Reefs of the colonial polychaete Sabellaria spinulosa stood in the way of shrimp trawling and became destroyed together with the associated fauna. A subtidal Zostera marina bed was wiped out in 1934 by a natural epidemic disease but never succeeded in reestablishing itself. The associated fauna disappeared. Large epibenthic predators and scavengers (crabs, snails and starfish) survived all these changes. The total number of species remained approximately at the same level but molluscs experienced losses and polychaetes diversified. Overall abundance increased with a disproportionately large share of a few species (Mytilus edulis, Balanus crenatus, Cerastoderma edule, Scoloplos armiger). The subtidal fauna of the Wadden Sea proved to be vulnerable to human disturbance; thus, the present community can no longer be viewed as the outcome of entirely natural processes.

  3. Optical properties of humic substances and CDOM: effects of borohydride reduction.

    PubMed

    Ma, Jiahai; Del Vecchio, Rossana; Golanoski, Kelli S; Boyle, Erin S; Blough, Neil V

    2010-07-15

    Treatment of Suwanee River humic (SRHA) and fulvic (SRFA) acids, a commercial lignin (LAC), and a series of solid phase extracts (C18) from the Middle Atlantic Bight (MAB extracts) with sodium borohydride (NaBH(4)), a selective reductant of carbonyl-containing compounds including quinones and aromatic ketones, produces a preferential loss of visible absorption (> or = 50% for SRFA) and substantially enhanced, blue-shifted fluorescence emission (2- to 3-fold increase). Comparison of the results with those obtained from a series of model quinones and hydroquinones demonstrates that these spectral changes cannot be assigned directly to the absorption and emission of visible light by quinones/hydroquinones. Instead, these results are consistent with a charge transfer model in which the visible absorption is due primarily to charge transfer transitions arising among hydroxy- (methoxy-) aromatic donors and carbonyl-containing acceptors. Unlike most of the model hydroquinones, the changes in optical properties of the natural samples following NaBH(4) reduction were largely irreversible in the presence of air and following addition of a Cu(2+) catalyst, providing tentative evidence that aromatic ketones (or other similar carbonyl-containing structures) may play a more important role than quinones in the optical properties of these materials.

  4. Analytical models for the groundwater tidal prism and associated benthic water flux

    USGS Publications Warehouse

    King, Jeffrey N.; Mehta, Ashish J.; Dean, Robert G.

    2010-01-01

    The groundwater tidal prism is defined as the volume of water that inundates a porous medium, forced by one tidal oscillation in surface water. The pressure gradient that generates the prism acts on the subterranean estuary. Analytical models for the groundwater tidal prism and associated benthic flux are presented. The prism and flux are shown to be directly proportional to porosity, tidal amplitude, and the length of the groundwater wave; flux is inversely proportional to tidal period. The duration of discharge flux exceeds the duration of recharge flux over one tidal period; and discharge flux continues for some time following low tide. Models compare favorably with laboratory observations and are applied to a South Atlantic Bight study area, where tide generates an 11-m3 groundwater tidal prism per m of shoreline, and drives 81 m3 s −1 to the study area, which describes 23% of an observational estimate. In a marine water body, the discharge component of any oscillatory benthic water flux is submarine groundwater discharge. Benthic flux transports constituents between groundwater and surface water, and is a process by which pollutant loading and saltwater intrusion may occur in coastal areas.

  5. Bio-Optical and Remote Sensing Observations in Chesapeake Bay. Chapter 7

    NASA Technical Reports Server (NTRS)

    Harding, Lawrence W., Jr.; Magnuson, Andrea

    2003-01-01

    The high temporal and spatial resolution of satellite ocean color observations will prove invaluable for monitoring the health of coastal ecosystems where physical and biological variability demands sampling scales beyond that possible by ship. However, ocean color remote sensing of Case 2 waters is a challenging undertaking due to the optical complexity of the water. The focus of this SIMBIOS support has been to provide in situ optical measurements from Chesapeake Bay (CB) and adjacent mid-Atlantic bight (MAB) waters for use in algorithm development and validation efforts to improve the satellite retrieval of chlorophyll (chl a) in Case 2 waters. CB provides a valuable site for validation of data from ocean color sensors for a number of reasons. First, the physical dimensions of the Bay (> 6,500 km2) make retrievals from satellites with a spatial resolution of approx. 1 km (i.e., SeaWiFS) or less (i.e., MODIS) reasonable for most of the ecosystem. Second, CB is highly influenced by freshwater flow from major rivers, making it a classic Case 2 water body with significant concentrations of chlorophyll, particulates and chromophoric dissolved organic matter (CDOM) that highly impact the shape of reflectance spectra.

  6. Seasonal, annual, and spatial variation in the development of hard bottom communities

    NASA Astrophysics Data System (ADS)

    Harms, J.; Anger, K.

    1983-06-01

    The development of hard bottom communities has been studied on test panels in Helgoland Harbour (German Bight) since 1977. Settlement and growth of epibenthic species was examined monthly. Natural variation in different seasons, years, and at three stations (the latter, only in 1981 and 1982) was investigated. At Station A (Binnenhafen), barnacles (Balanus crenatus) and polychaetes (Polydora ciliata) were always among the first settlers in spring. They were followed by other barnacles (Elminius modestus, Balanus improvisus) and by colonial ascidians (Botryllus schlosseri). The latter species often dominated from August to October, and tended to overgrow the barnacle populations. E. modestus showed strong annual variation, probably due to extremely low winter temperatures: after the cold winter of 1978/79, its populations were less dense than in previous years. In 1981 they recovered, and settlement increased again, but the cold winter 1981/82 damaged the population again. At Station B (Nordosthafen), mussels (Mytilus edulis) soon covered barnacles and empty space. By October they had monopolized the fouling community. At Station C (Südhafen), barnacle settlement in spring was followed by an overgrowth of hydrozoans ( Laomedea spec.). In summer, ascidians ( Ciona intestinalis and Ascidiella aspersa) settled and began to dominate. Barnacles were weaker in the competition for space as opposed to later colonizers at all three stations.

  7. Regional monitoring programs in the United States: Synthesis of four case studies from Pacific, Atlantic, and Gulf Coasts

    USGS Publications Warehouse

    Tango, Peter J.; Schiff, K.; Trowbridge, P.R.; Sherwood, E.T.; Batiuk, R.A.

    2016-01-01

    Water quality monitoring is a cornerstone of environmental protection and ambient monitoring provides managers with the critical data they need to take informed action. Unlike site-specific monitoring that is at the heart of regulatory permit compliance, regional monitoring can provide an integrated, holistic view of the environment, allowing managers to obtain a more complete picture of natural variability and cumulative impacts, and more effectively prioritize management actions. By reviewing four long-standing regional monitoring programs that cover portions of all three coasts in the United States – Chesapeake Bay, Tampa Bay, Southern California Bight, and San Francisco Bay – important insights can be gleaned about the benefits that regional monitoring provides to managers. These insights include the underlying reasons that make regional monitoring programs successful, the challenges to maintain relevance and viability in the face of ever-changing technology, competing demands and shifting management priorities. The lessons learned can help other managers achieve similar successes as they seek to establish and reinvigorate their own monitoring programs.

  8. Impact of the Extreme Warming of 2012 on Shelfbreak Frontal Structure North of Cape Hatteras

    NASA Astrophysics Data System (ADS)

    Gawarkiewickz, G.

    2014-12-01

    Continental shelf circulation north of Cape Hatteras is complex, with southward flowing Middle Atlantic Bight shelf water intersecting the Gulf Stream and subducting offshore into the Gulf Stream. In May, 2012, a cruise was conducted in order to study the shelf circulation and acoustic propagation through fish schools in the area. An important aspect of the study was to use Autonomous Underwater Vehicles to map fish schools with a sidescan sonar. High-resolution hydrographic surveys to map the continental shelf water masses and shelfbreak frontal structure were sampled to relate oceanographic conditions to the fish school distributions. The cold pool water mass over the continental shelf in May 2012 was extremely warm, with temperature anomalies of up to 5 Degrees C relative to observations from the same area in May, 1996. The normal cross-shelf temperature gradients within the shelfbreak front were not present because of the warming. As a result, the shelf density field was much more buoyant than usual, which led to an accelerated shelfbreak jet. Moored velocity measurements at the 60 m isobath recorded alongshelf flow of as much as 0.6 m/s. The anticipated fish species were not observed over the continental shelf. Some comments on the forcing leading to the large scale warming will be presented, along with a brief discussion of the impact of the warming on the marine ecosystem in the northeast U.S.

  9. Early diagenesis of trace metals used as an indicator of past productivity changes in coastal sediments

    SciTech Connect

    Lapp, B. ); Balzer, W. )

    1993-10-01

    In sediments of Kiel Bight, which differ significantly in their redox-states and the rates of C[sub org] degradation, depth profiles of both dissolved and solid-phase Fe, Mn, Cd, Cu, Ni, and Co were measured. Porewater fluxes of Cd, Cu and Ni were significantly higher at shallower (more oxic) stations as compared to highly reducing deeper subthermocline sediments, while Mn fluxes behaved the opposite way. When normalized to Fe for grain size correction the measured solid-phase metal contents revealed that the high porewater flux has led to near surface depletion of Mn from more anoxic sediments and to a reduced rate of accumulation of anthropogenic Cd in more oxic sediments. This difference in early diagenetic behaviour suggests the use of these metals as a proxy for the redox state and the intensity of carbon recycling. Contrary to the recent sediment layers the normalized metal contents of preindustrially deposited sediment layers were similar for both metals at all stations. Thus, at stations having highly anoxic sediments today, the preindustrial benthic flux must have been lower for Mn and higher for Cd, reflecting a shift from more oxic to more reducing conditions in subthermocline sediments during the last 100 years. This change of the redox state in subthermocline sediments reflects an increase of primary production and of subsequent C[sub org] input to the sediment due to eutrophication which accompanied industrialization.

  10. What shall we do with the drunken sailor? Effects of alcohol on the performance of ship operators.

    PubMed

    Ritz-Timme, Stefanie; Thome, Mark; Grütters, Geertje; Grütters, Martin; Reichelt, Jan A; Bilzer, Norbert; Kaatsch, Hans-Jürgen

    2006-01-06

    The purpose of this study was to specify the effects of alcohol on the performance of ship operators as a contribution to the development of new strategies against the risks of alcohol in water traffic. The nautical performance of 21 captains before and after alcohol consumption was assessed on a ship piloting simulator. The simulated scenarios represented passages of a container vessel through the German Bight. Performance was examined by nautical instructors according to standardised protocols. Mean (S.D.) blood alcohol concentrations (BACs) of 0.100 (0.024) g/dl before and 0.100 (0.017) g/dl after the performance trial resulted in striking effects on the nautical performance. The categories most severely affected were foresight and analysis of situation (impairment in 18 of 21 cases), concentration (impairment in 16 of 21 cases), accurateness, risk disposition and navigation (impairment in 15 of 21 cases). Chart work, preparation and communication were impaired in 12, 11 and 10 of 21 cases, respectively. None of the participants were capable to operate the simulated ship with an adequate safety after ingestion of alcohol. From these findings, and in consideration of the well-established impairment of a multitude of mental and physical functions by alcohol, it can be concluded that even low BACs bear high risks in water traffic, a concentration above 0.1 g/dl will hinder a sufficiently safe performance of ship operators. This should be considered in alcohol education and legislation.

  11. Drivers of spring and summer variability in the coastal ocean offshore of Cape Cod, MA

    NASA Astrophysics Data System (ADS)

    Kirincich, Anthony R.; Gawarkiewicz, Glen G.

    2016-03-01

    The drivers of spring and summer variability within the coastal ocean east of Cape Cod, Massachusetts, a critical link between the Gulf of Maine and Mid-Atlantic Bight, are investigated using 2 years of shipboard and moored hydrographic and velocity observations from 2010 and 2011. The observations reveal sharp differences in the spring transition and along-shelf circulation due to variable freshwater and meteorological forcing, along with along-shelf pressure gradients. The role of the along-shelf pressure gradient is inferred using in situ observations of turbulent momentum flux, or Reynolds stresses, estimated from the ADCP-based velocities using recently developed methods and an inversion of the along-shelf momentum balance. During spring, the locally relevant along-shelf pressure gradient contains a sizable component that is not coupled to the along-shelf winds and often opposes the regional sea level gradient. Together with the winds, local pressure gradients dominate along-shelf transport variability during spring, while density-driven geostrophic flows appear to match the contribution of the local winds during summer. These results suggest that local effects along the Outer Cape have the potential to cause significant changes in exchange between the basins.

  12. Trace metals in sediments and Zostera marina of San Ignacio and Ojo de Liebre lagoons in the central pacific coast of Baja California, Mexico.

    PubMed

    Macías-Zamora, J V; Sánchez-Osorio, J L; Ríos-Mendoza, L M; Ramírez-Alvarez, N; Huerta-Díaz, M A; López-Sánchez, D

    2008-08-01

    San Ignacio and Ojo de Liebre lagoons in central Baja California, Mexico are nursery and grazing grounds for whales and turtles. Ojo de Liebre Lagoon also supports a salt mine operation. By concentrating trace metals via evaporation, this activity might harm biota. Consequently, salt mining might be incompatible with the lagoon's ecological role. Eelgrass can incorporate these elements and reroute them to other organisms. Trace metals in sediments (Cd, Co, Cu, Mn, Ni, Pb, Zn, and Fe) were measured at both lagoons. Some (Cu, Mn, Pb, and Zn) were also measured in Zostera marina patches at both lagoons. The results did not show elevated metal concentration at any lagoon, either for sediments or eelgrass. No statistically significant differences between lagoons were found. However, eelgrass at both lagoons showed larger concentration ranges than in sediments. Also, a correlation exists between sediment metal concentration and its concentration in eelgrass. Surprisingly, several sediment metal concentrations are higher than those considered as elevated for the Southern California Bight.

  13. Validation of genetic algorithm-based optimal sampling for ocean data assimilation

    NASA Astrophysics Data System (ADS)

    Heaney, Kevin D.; Lermusiaux, Pierre F. J.; Duda, Timothy F.; Haley, Patrick J.

    2016-10-01

    Regional ocean models are capable of forecasting conditions for usefully long intervals of time (days) provided that initial and ongoing conditions can be measured. In resource-limited circumstances, the placement of sensors in optimal locations is essential. Here, a nonlinear optimization approach to determine optimal adaptive sampling that uses the genetic algorithm (GA) method is presented. The method determines sampling strategies that minimize a user-defined physics-based cost function. The method is evaluated using identical twin experiments, comparing hindcasts from an ensemble of simulations that assimilate data selected using the GA adaptive sampling and other methods. For skill metrics, we employ the reduction of the ensemble root mean square error (RMSE) between the "true" data-assimilative ocean simulation and the different ensembles of data-assimilative hindcasts. A five-glider optimal sampling study is set up for a 400 km × 400 km domain in the Middle Atlantic Bight region, along the New Jersey shelf-break. Results are compared for several ocean and atmospheric forcing conditions.

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

    USGS Publications Warehouse

    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.

  15. Airborne infrared remote sensing characterization of submesoscale eddies

    NASA Astrophysics Data System (ADS)

    Smith, Geoffrey; Marmorino, George; Miller, W. David; North, Ryan; Angel-Benavides, Ingrid; Baschek, Burckard

    2016-11-01

    Airborne remote sensing surveys off Santa Catalina Island, CA (33°30' N118°31' W) were conducted as part of a larger study of the occurrence and behavior of submesoscale phenomena. This builds upon previous work by DiGiacomo and Holt, who utilized SAR imagery to characterize the size and distribution of predominately cyclonic 'spiral eddies' in the Southern California Bight. In the present work the thermal surface expression of a single cyclonic eddy captured in February 2013 will be investigated. Advances made in methods to estimate eddy circulation and vorticity directly from the thermal imagery will be discussed and compared with in situ measurements. Inferences about localized mixing and flow instabilities can also be drawn from the imagery, and these too will be discussed in the context of in situ data. A simple model will be offered describing the three dimensional flow in the core of the eddy and how that can be used to explain the surface imagery. Connections between the signatures surrounding the eddy and the core itself will also be discussed in the context of the model.

  16. Delphinid behavioral responses to incidental mid-frequency active sonar.

    PubMed

    Henderson, E Elizabeth; Smith, Michael H; Gassmann, Martin; Wiggins, Sean M; Douglas, Annie B; Hildebrand, John A

    2014-10-01

    Opportunistic observations of behavioral responses by delphinids to incidental mid-frequency active (MFA) sonar were recorded in the Southern California Bight from 2004 through 2008 using visual focal follows, static hydrophones, and autonomous recorders. Sound pressure levels were calculated between 2 and 8 kHz. Surface behavioral responses were observed in 26 groups from at least three species of 46 groups out of five species encountered during MFA sonar incidents. Responses included changes in behavioral state or direction of travel, changes in vocalization rates and call intensity, or a lack of vocalizations while MFA sonar occurred. However, 46% of focal groups not exposed to sonar also changed their behavior, and 43% of focal groups exposed to sonar did not change their behavior. Mean peak sound pressure levels when a behavioral response occurred were around 122 dB re: 1 μPa. Acoustic localizations of dolphin groups exhibiting a response gave insight into nighttime movement patterns and provided evidence that impacts of sonar may be mediated by behavioral state. The lack of response in some cases may indicate a tolerance of or habituation to MFA sonar by local populations; however, the responses that occur at lower received levels may point to some sensitization as well.

  17. Trophic look at soft-bottom communities - Short-term effects of trawling cessation on benthos

    NASA Astrophysics Data System (ADS)

    Dannheim, Jennifer; Brey, Thomas; Schröder, Alexander; Mintenbeck, Katja; Knust, Rainer; Arntz, Wolf E.

    2014-01-01

    The trophic structure of the German Bight soft-bottom benthic community was evaluated for potential changes after cessation of bottom trawling. Species were collected with van-Veen grabs and beam trawls. Trophic position (i.e. nitrogen stable isotope ratios, δ15N) and energy flow (i.e. species metabolism approximated by body mass scaled abundance) of dominant species were compared in trawled areas and an area protected from fisheries for 14 months in order to detect trawling cessation effects by trophic characteristics. At the community level, energy flow was lower in the protected area, but we were unable to detect significant changes in trophic position. At the species level energy flow in the protected area was lower for predating/scavenging species but higher for interface feeders. Species trophic positions of small predators/scavengers were lower and of deposit feeders higher in the protected area. Major reasons for trophic changes after trawling cessation may be the absence of artificial and additional food sources from trawling likely to attract predators and scavengers, and the absence of physical sediment disturbance impacting settlement/survival of less mobile species and causing a gradual shift in food availability and quality. Our results provide evidence that species or community energy flow is a good indicator to detect trawling induced energy-flow alterations in the benthic system, and that in particular species trophic properties are suitable to capture subtle and short-term changes in the benthos following trawling cessation.

  18. Physical processes around a cuspate foreland:. implications to the evolution and long-term maintenance of a cape-associated shoal

    NASA Astrophysics Data System (ADS)

    McNinch, Jesse E.; Luettich, Richard A.

    2000-12-01

    Understanding across-margin transport has long been recognized as crucial for wise management of our coastline and shelf waters. Issues related to sewage outfalls, nutrient and pollutant dispersal, carbon export, and shoreline sediment budgets all require an understanding of these processes. Across-margin transport of water and sediment at cuspate foreland headlands has been largely unrecognized, and the processes responsible for this export unappreciated. We examined physical process on Cape Lookout Shoal, a cape-associated shoal on the North Carolina continental shelf, through numerical modeling and field observations of near-bottom currents. The cuspate foreland setting of the northern South Atlantic Bight has been previously characterized as wave-dominated with a principal alongshore directed sediment transport and physical circulation forced by wave and wind-driven currents along the inner and mid-shelf. Our findings instead suggest that a seaward-directed, tidal-driven headland flow many play a significant role in the direction of net sediment transport on the shoal and ultimately its location and long-term maintenance. The shoal's location relative to the promontory-induced residual eddies and the region of active deposition differs from traditionally held ideas on sedimentary processes at headland-related sand banks. In addition, the headland flows may also serve as a first-order mechanism for rapidly exporting nearshore and estuarine waters to the outer-shelf.

  19. Analytical characterization of selective benthic flux components in estuarine and coastal waters

    USGS Publications Warehouse

    King, Jeffrey N.

    2011-01-01

    Benthic flux is the rate of flow across the bed of a water body, per unit area of bed. It is forced by component mechanisms, which interact. For example, pressure gradients across the bed, forced by tide, surface gravity waves, density gradients, bed–current interaction, turbulence, and terrestrial hydraulic gradients, drive an advective benthic flux of water and constituents between estuarine and coastal waters, and surficial aquifers. Other mechanisms also force benthic flux, such as chemical gradients, bioturbation, and dispersion. A suite of component mechanisms force a total benthic flux at any given location, where each member of the suite contributes a component benthic flux. Currently, the types and characteristics of component interactions are not fully understood. For example, components may interact linearly or nonlinearly, and the interaction may be constructive or destructive. Benthic flux is a surface water–groundwater interaction process. Its discharge component to a marine water body is referred to, in some literature, as submarine groundwater discharge. Benthic flux is important in characterizing water and constituent budgets of estuarine and coastal systems. Analytical models to characterize selective benthic flux components are reviewed. Specifically, these mechanisms are for the component associated with the groundwater tidal prism, and forced by surface gravity wave setup, surface gravity waves on a plane bed, and the terrestrial hydraulic gradient. Analytical models are applied to the Indian River Lagoon, Florida; Great South Bay, New York; and the South Atlantic Bight in South Carolina and portions of North Carolina.

  20. Small-scale slump deposits, Middle Atlantic Continental Slope, off eastern United States

    USGS Publications Warehouse

    Knebes, H.J.; Carson, Bobb

    1979-01-01

    Analyses of 24 high-resolution seismic-reflection profiles that were collected during local and regional surveys show that small-scale slump deposite are ubiquitous whthin the intercanyon areas of the Continental Slope of the Middle Atlantic Bight. The deposits involve the upper 10-90 m of sediments, extend downslops for 1.8-7.2 km, and are present at water depths ranging from 545 to 1500 m. The characteristics of the deposits vary from thin, homogeneous or fairly regularly bedded lenses of sediment, to masses of intermediate thickness with contorted bedding, to relatively large slump blocks. A detailed survey of one slump mass just south of Hudson Canyon (by means of close-spaced Minisparker profiles and sediment cores) showed that it had a thickness of about 30 m and a volume of at least 0.4 km3 and consisted of homogeneous clay which accumulated rapidly during the late Pleistocene or Holocene. Although some of the slump deposits undoubtedly are relict, stemming from sediment instability porduced by rapid deposition during Pleistocene sea-level regressions, others were formed relatively recently. Possible causes of modern slumps include gas generation in the sediments, bottom-water turbulence on the upper slope, and shallow faulting. This study indicates that small-scale slumping in the intercanyon areas may be an important process in transporting sediments to the deep sea and suggests that recent mass movements may constitute a geologic hazard to future economic development of this part of the Continental Slope. ?? 1979.