Woods Hole Coastal and Marine Science Center
Publications by year, USGS Woods Hole Coastal and Marine Science Center
All Publications by WHCMSC Authors for the year 2011
Andrews, Brian D., Ackerman, Seth D., Baldwin, Wayne E., and Barnhardt, Walter A., 2010, Geophysical and sampling data from the inner continental shelf; northern Cape Cod Bay, Massachusetts:
U.S. Geological Survey Open-File Report 2010-1006
. Online at http://pubs.usgs.gov/of/2010/1006/
The U.S. Geological Survey (USGS) and the Massachusetts Office of Coastal Zone Management (CZM) have cooperated to map approximately 480 km2 of the inner continental shelf in northern Cape Cod Bay, MA. This report contains geophysical and sampling data collected by the USGS during five research cruises between 2006 and 2008. The geophysical data include (1) swath bathymetry from interferometric sonar, (2) acoustic backscatter from interferometric and sidescan sonars, and (3) subsurface stratigraphy and structure from seismic-reflection profilers. The seafloor sampling data include sediment samples, photographs, and video tracklines.
These spatial data support research on the influence that sea-level change and sediment supply have on coastal evolution and help identify the type, distribution, and quality of subtidal marine habitats within the coastal zone of Massachusetts.
Coleman, Felicia C., Scanlon, Kathryn M., and Koenig, Christopher C., 2011, Groupers on the edge; shelf-edge spawning habitat in and around marine reserves of the northeastern Gulf of Mexico:
, v. 63
, no. 4
, pp. 456-474
. Online at 10.1080/00330124.2011.585076
The northeastern Gulf of Mexico contains some of the most diverse and productive marine habitat in the United States. Much of this habitat, located on the shelf edge in depths of 50 to 120 m, supports spawning for many economically important species, including groupers. Here, we couple acoustic surveys with georeferenced videography to describe the primary spatial and geologic features of spawning aggregation sites for four economically important species: gag (Mycteroperca microlepis), scamp (M. phenax), red grouper (Epinephelus morio), and red snapper (Lutjanus campechanus), with notes on fish distribution and abundance and spawning activities. We provide information on movement patterns of reef fish determined using acoustic telemetry. Finally, we discuss the possible coupling of geomorphology with hydrographic features to influence the overall productivity of the region and the importance of spatial fishery management in sustaining that productivity.
Denny, J.F., Foster, D.S., Worley, C.R., and Irwin, B.J., 2011, Geophysical data collected in the St. Clair River between Michigan and Ontario, Canada (2008):
U.S. Geological Survey Open-File Report 2010-1035, online with pdf
. Online at http://pubs.usgs.gov/of/2010/1035/
In 2008, the U.S. Geological Survey (USGS), Woods Hole Coastal and Marine Science Center (WHCMSC), in cooperation with the U.S. Army Corps of Engineers conducted a geophysical and sampling survey of the riverbed of the Upper St. Clair River between Port Huron, MI, and Sarnia, Ontario, Canada. The objectives were to define the Quaternary geologic framework of the St. Clair River to evaluate the relationship between morphologic change of the riverbed and underlying stratigraphy. This report presents the geophysical and sample data collected from the St. Clair River, May 29June 6, 2008 as part of the International Upper Great Lakes Study, a 5-year project funded by the International Joint Commission of the United States and Canada to examine whether physical changes in the St. Clair River are affecting water levels within the upper Great Lakes, to assess regulation plans for outflows from Lake Superior, and to examine the potential effect of climate change on the Great Lakes water levels ( http://www.iugls.org). This document makes available the data that were used in a separate report, U.S. Geological Survey Open-File Report 20091137, which detailed the interpretations of the Quaternary geologic framework of the region. This report includes a description of the suite of high-resolution acoustic and sediment-sampling systems that were used to map the morphology, surficial sediment distribution, and underlying geology of the Upper St. Clair River during USGS field activity 2008-016-FA . Video and photographs of the riverbed were also collected and are included in this data release. Future analyses will be focused on substrate erosion and its effects on river-channel morphology and geometry. Ultimately, the International Upper Great Lakes Study will attempt to determine where physical changes in the St. Clair River affect water flow and, subsequently, water levels in the Upper Great Lakes.
Gaetani, G.A., Cohen, A.L., Wang, Z, Crusius, J., 2011, A Rayleigh-based, multi-element approach to coral thermometry:
Geochimica et Cosmochimica Acta
, v. 75
, no. 7
, pp. 1920-1932
This study presents a new approach to coral thermometry that deconvolves the influence of water temperature on skeleton composition from that of vital effects, and has the potential to provide estimates of growth temperatures that are accurate to within a few tenths of a degree Celsius from both tropical and cold-water corals. Our results provide support for a physico-chemical model of coral biomineralization, and imply that Mg2+ substitutes directly for Ca2+ in biogenic aragonite. Recent studies have identified Rayleigh fractionation as an important influence on the elemental composition of coral skeletons. Daily, seasonal and interannual variations in the amount of aragonite precipitated by corals from each batch of calcifying fluid can explain why the temperature dependencies of elemental ratios in coral skeleton differ from those of abiogenic aragonites, and are highly variable among individual corals. On the basis of this new insight into the origin of vital effects in coral skeleton, we developed a Rayleigh-based, multi-element approach to coral thermometry. Temperature is resolved from the Rayleigh fractionation signal by combining information from multiple element ratios (e.g., Mg/Ca, Sr/Ca, Ba/Ca) to produce a mathematically over-constrained system of Rayleigh equations. Unlike conventional coral thermometers, this approach does not rely on an initial calibration of coral skeletal composition to an instrumental temperature record. Rather, considering coral skeletogenesis as a biologically mediated, physico-chemical process provides a means to extract temperature information from the skeleton composition using the Rayleigh equation and a set of experimentally determined partition coefficients. Because this approach is based on a quantitative understanding of the mechanism that produces the vital effect it should be possible to apply it both across scleractinian species and to corals growing in vastly different environments. Where instrumental temperature records are available, a Rayleigh-based framework allows the effects of stress on coral calcification to be identified on the basis of anomalies in the skeletal composition.
Ganju, N.K., Dickhudt, P.J., Thomas, J.A., Borden, J., Sherwood, C.R., Montgomery, E., Twomey, E., and Martini, M., 2011, Summary of oceanographic and water-quality measurements in West Falmouth Harbor and Buzzards Bay, Massachusetts, 2009-2010:
U.S. Geological Survey Open-File Report 2011-1113
. Online at http://pubs.usgs.gov/of/2011/1113/
This data report presents oceanographic and water-quality observations made at six locations in West Falmouth Harbor and Buzzards Bay, Massachusetts, from August 2009 to September 2010. Both Buzzards Bay and West Falmouth Harbor are estuarine embayments; the input of freshwater on the eastern margin of Buzzards Bay adjacent to Cape Cod and West Falmouth Harbor is largely due to groundwater. In West Falmouth Harbor, the groundwater that seeps into the harbor is characterized by relatively high levels of nitrate. This high nitrate load has modified the ecology of the harbor (Howes and others, 2006) and may be a significant source of nitrate to Buzzards Bay during seasons with low biological nitrate uptake. The U.S. Geological Survey undertook these measurements to improve understanding of circulation, residence time, and water quality in the harbor and bay. We set up and monitored multiple sites in both Buzzards Bay and West Falmouth Harbor, measuring depth, water velocity,salinity, pH, dissolved oxygen, chlorophyll-a, and nitrate concentration. In this report we present the processed time-series data at these locations and provide access to the data and metadata. The results will be used to understand circulation mechanisms and verify numerical models of hydrodynamics and biogeochemistry.
Gutierrez, B.T., Plant, N.G., and Thieler, E.R, 2011, A Bayesian Network to predict vulnerability to sea-level rise: data report:
U.S. Geological Survey Digital Data Series-601
. Online at http://pubs.usgs.gov/ds/601
During the 21st century, sea-level rise is projected to have a wide range of effects on coastal environments, development, and infrastructure. Consequently, there has been an increased focus on developing modeling or other analytical approaches to evaluate potential impacts to inform coastal management. This report provides the data that were used to develop and evaluate the performance of a Bayesian network designed to predict long-term shoreline change due to sea-level rise. The data include local rates of relative sea-level rise, wave height, tide range, geomorphic classification, coastal slope, and shoreline-change rate compiled as part of the U.S. Geological Survey Coastal Vulnerability Index for the U.S. Atlantic coast. In this project, the Bayesian network is used to define relationships among driving forces, geologic constraints, and coastal responses. Using this information, the Bayesian network is used to make probabilistic predictions of shoreline change in response to different future sea-level-rise scenarios.
Hapke, C.J., and Thieler, E.R., 2011, USGS Science for the Nation's Changing Coasts: Shoreline Change Research:
U.S. Geological Survey Fact Sheet 2011-3073
. Online at http://pubs.usgs.gov/fs/2011/3073
The demands of increasing human population in the coastal zone create competition with coastal habitat preservation and with recreational and commercial uses of the coast and nearshore waters. As climate changes over the coming century, these problems facing coastal communities will likely worsen. Good management and policy decision-making require baseline information on the rates, trends, and scientific understanding of the processes of coastal change on a regional to national scale. To address this need, the U.S. Geological Survey (USGS) is engaged in a research project of national scope to measure, report, and interpret historical shoreline change along open-ocean coasts of the United States. One of the primary goals of this project is to understand shoreline change hazards using methods that are comparable from one area of the country to another and that will allow for future, repeatable analyses of shoreline movement, coastal erosion, and land loss.
Hapke, Cheryl J., Himmelstoss, Emily A., Kratzmann, Meredith G., List, Jeffrey, and Thieler, E. Robert, 2011, National Assessment of Shoreline Change: Historical Shoreline Change along the New England and Mid-Atlantic Coasts:
U.S. Geological Survey Open-File Report 2010-1118
. Online at http://pubs.usgs.gov/of/2010/1118/
Beach erosion is a chronic problem along many open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information regarding past and present trends and rates of shoreline movement. There is also a need for a comprehensive analysis of shoreline movement that is consistent from one coastal region to another. To meet these national needs, the U.S. Geological Survey (USGS) is conducting an analysis of historical shoreline changes along open-ocean sandy shores of the conterminous United States and parts of Hawaii, Alaska, and the Great Lakes. One purpose of this work is to develop standard, repeatable methods for mapping and analyzing shoreline movement so that periodic, systematic, internally consistent updates regarding coastal erosion and land loss can be made nationally. In the case of this study, the shoreline is the interpreted boundary between the ocean water surface and the sandy beach. This report on the New England and Mid-Atlantic coasts is the fifth in a series of reports on historical shoreline change. Previous investigations include analyses and descriptive reports of the Gulf of Mexico, the Southeast Atlantic, and, for California, the sandy shoreline and the coastal cliffs. The rates of change presented in this report represent conditions up to the date of the most recent shoreline data and therefore are not intended for predicting future shoreline positions or rates of change. Because of the geomorphology of the New England and Mid-Atlantic (rocky coastlines, large embayments and beaches) as well as data gaps in some areas, this report presents beach erosion rates for 78 percent of the 1,360 kilometers of the New England and Mid-Atlantic coasts. The New England and Mid-Atlantic shores were subdivided into a total of 10 analysis regions for the purpose of reporting regional trends in shoreline change rates. The average rate of long-term shoreline change for the New England and Mid-Atlantic coasts was -0.5 meters per year with an uncertainty in the long-term trend of plus or minus 0.09 meters per year. The rate is based on shoreline change rates averaged from 21,184 individual transects, of which 68 percent were eroding. In both the long and short term, the average rates of shoreline change for New England and the Mid-Atlantic were erosional. Long-term erosion rates were generally lower in New England than in the Mid-Atlantic. This is a function of the dominant coastal geomorphology; New England has a greater percentage of shore types that tend to erode more slowly (rocky coasts, pocket beaches, and mainland beaches), whereas the Mid-Atlantic is dominated by more vulnerable barrier islands and dynamic spit/inlet environments. However, the percentage of coastline eroding was higher in New England than in the Mid-Atlantic, highlighting that although rates of shoreline erosion may not be extreme, coastal erosion is still widespread along this region of the U.S. coastline. The average rate of short-term shoreline change for the New England and Mid-Atlantic coasts was also erosional but the rate of erosion decreased in comparison to long-term rates. The net short-term rate as averaged along 17,045 transects was -0.3 meters per year. Uncertainties for these rates range from 0.06 to 0.1 meters per year depending on the data sources used in the rate calculations. Of transects used to measure short-term change, 60 percent were erosional, as compared to 65 percent of coast eroding in the long term. The slight decrease (5 percent) in the amount of coastline eroding may be related to an increase in the frequency and extent of nourishment programs and (or) the effects of hardened structures during the more recent time period. The most stable (lower rates of erosion) beaches were more commonly found in New England. Despite an overall lowering of the average rates of erosion from long-term to short-term, the amount
Himmelstoss, Emily, Kratzmann, Meredith, Hapke, Cheryl, Thieler, E. Robert, and List, Jeffery, 2011, The National Assessment of Shoreline Change; a GIS compilation of vector shorelines and associated shoreline change data for the New England and mid-Atlantic coasts:
U.S. Geological Survey Open-File Report 2010-1119, online
. Online at http://pubs.usgs.gov/of/2010/1119/
Sandy ocean beaches are a popular recreational destination, often surrounded by communities containing valuable real estate. Development is on the rise despite the fact that coastal infrastructure is subjected to flooding and erosion. As a result, there is an increased demand for accurate information regarding past and present shoreline changes. The U.S. Geological Survey's National Assessment of Shoreline Change Project has compiled a comprehensive database of digital vector shorelines and shoreline-change rates for the New England and Mid-Atlantic Coasts. There is currently no widely accepted standard for analyzing shoreline change. Existing measurement and rate-calculation methods vary from study to study and preclude combining results into statewide or regional assessments. The impetus behind the National Assessment project was to develop a standardized method that is consistent from coast to coast for measuring changes in shoreline position. The goal was to facilitate the process of periodically and systematically updating the results in an internally consistent manner.
Kneafsey, T.J., Lu, H., Winters, W.J., Boswell, R.M., Hunter, R.B., and Collett, T.S., 2011, Examination of core samples from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Effects of retrieval and preservation:
Journal of Marine and Petroleum Geology
, v. 28
, no. 2
, pp. 381-393
Collecting and preserving undamaged core samples containing gas hydrates from depth is difficult because of the pressure and temperature changes encountered upon retrieval. Hydrate-bearing core samples were collected at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well in February 2007. Coring was performed while using a custom oil-based drilling mud, and the cores were retrieved by a wireline. The samples were characterized and subsampled at the surface under ambient winter arctic conditions. Samples thought to be hydrate bearing were preserved either by immersion in liquid nitrogen (LN), or by storage under methane pressure at ambient arctic conditions, and later depressurized and immersed in LN. Eleven core samples from hydrate-bearing zones were scanned using x-ray computed tomography to examine core structure and homogeneity. Features observed include radial fractures, spalling-type fractures, and reduced density near the periphery. These features were induced during sample collection, handling, and preservation. Isotopic analysis of the methane from hydrate in an initially LN-preserved core and a pressure-preserved core indicate that secondary hydrate formation occurred throughout the pressurized core, whereas none occurred in the LN-preserved core, however no hydrate was found near the periphery of the LN-preserved core. To replicate some aspects of the preservation methods, natural and laboratory-made saturated porous media samples were frozen in a variety of ways, with radial fractures observed in some LN-frozen sands, and needle-like ice crystals forming in slowly frozen clay-rich sediments. Suggestions for hydrate-bearing core preservation are presented.
Lentz, Erika E., and Hapke, Cheryl J., 2011, The Development of a Probabilistic Approach to Forecast Coastal Change:
Coastal Sediments Conference
, pp. 1853 - 1866
. Online at 10.1142/9789814355537_0140
This study demonstrates the applicability of a Bayesian probabilistic model as an effective tool in predicting post-storm beach changes along sandy coastlines. Volume change and net shoreline movement are modeled for two study sites at Fire Island, New York in response to two extratropical storms in 2007 and 2009. Both study areas include modified areas adjacent to unmodified areas in morphologically different segments of coast. Predicted outcomes are evaluated against observed changes to test model accuracy and uncertainty along 163 cross-shore transects. Results show strong agreement in the cross validation of predictions vs. observations, with 70-82% accuracies reported. Although no consistent spatial pattern in inaccurate predictions could be determined, the highest prediction uncertainties appeared in locations that had been recently replenished. Further testing and model refinement are needed; however, these initial results show that Bayesian networks have the potential to serve as important decision-support tools in forecasting coastal change.
McMullen, K.Y., Poppe, L.J., Ackerman, S.D., Blackwood, D.S., Schaer, J.D., Nadeau ,M.A., and Wood, D.A., 2011, Surficial geology of the sea floor in central Rhode Island Sound, southeast of Point Judith, Rhode Island:
U.S. Geological Survey Open-File Report 2011-1005
. Online at http://pubs.usgs.gov/of/2011/1005/
The U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) are working together to study sea-floor environments off the northeast coast of the United States. During 2008, NOAA survey H11996 collected multibeam echosounder data in a 65-square kilometer area in central Rhode Island Sound, southeast of Point Judith, Rhode Island. During 2010, the USGS collected bottom photographs and sediment samples from 25 stations in this study area. The bathymetry, photography, and sediment data are used to interpret sea-floor features including scour depressions, sand waves, trawl marks, and dredge spoils. Scour depressions cover the bathymetric highs in much of the study area. Sand waves are located mostly in the southwest, and trawl marks tend to be in the northern regions. Dredge spoils are located at a disposal site in a bathymetric low in the western end of the study area. Most stations have a sea-floor surface of sand or silty sand, but eight of the stations have boulders to pea-sized gravel or gravelly sediment on the surface. Photographs show sandy areas typically have scattered burrows, shells, amphipod communities, and worm tubes. Boulders and cobbles are commonly overgrown with hydrozoans and anemones.
Moore, Laura, List, Jeffrey H., Williams, Jeffress, and Patsch, Kiki, 2011, Barriers on the brink? The complex intertwined roles of geologic framework, sediment availability and sea-level rise in island evolution:
Coastal Sediments 2011
, pp. 272-285
. Online at 10.1142/9789814355537_0021
Sensitivity experiments in the North Carolina Outer Banks (OBX) have previously revealed that substrate sand proportion, followed by substrate slope, sea-level rise rate and sediment-loss rate are the most important factors in determining how barrier islands respond to sea-level rise. High sediment-loss rates and low substrate sand proportions cause barriers to be smaller and more deeply incised. Thus, as sea level rise rates increase, more deeply incised barriers do not need to migrate as far landward as larger, less-incised barriers to liberate sand from the shoreface. However, if the combination of sand losses and substrate sand proportions requires a barrier to migrate landward faster than the shoreface can erode to replenish losses, a barrier will change state and begin to disintegrate. Because the substrate of the OBXis sand-rich, these barriers are likely to persist in the near-term. In contrast, model simulations for the Chandeleur Islands, Louisiana suggest sediment loss rates are too high and/or substrate sand proportions are too low to be matched by liberation of shorefacesand. These simulations further suggest that a state change, from a landward-migrating barrier system to a subaqueous shoal complex, is either already underway or imminent.
Mosher, D., Shimeld, J., Hutchinson, D., Lebedeva-Ivanova, N., and Chapman, B, 2011, Submarine Landslides in Arctic Sedimentation: Canadian Basin:
Submarine Landslides Volume
, v. 31
, pp. 147-157
. Online at 10.1007/978-94-007-2162-3_13
Canada Basin of the Arctic Ocean is the least studied ocean basin in the World. Marine seismic field
programs were conducted over the past 6 years using Canadian and American icebreakers. These expeditions
acquired more than 14,000 line-km of multibeam bathymetric and multi-channel seismic reflection data
over abyssal plain, continental rise and slope regions of Canada Basin; areas where little or no
seismic reflection data existed previously. Canada Basin is a turbidite-filled basin with flat-lying
reflections correlateable over 100s of km. For the upper half of the sedimentary succession, evidence
of sedimentary processes other than turbidity current deposition is rare. The Canadian Archipelago
and Beaufort Sea margins host stacked mass transport deposits from which many of these turbidites
appear to derive. The stratigraphic succession of the MacKenzie River fan is dominated by mass
transport deposits; one such complex is in excess of 132,000 km2 in area and underlies much of
the southern abyssal plain. The modern seafloor is also scarred with escarpments and mass failure
deposits; evidence that submarine landsliding is an ongoing process. In its latest phase of
development, Canada Basin is geomorphologically confined with stable oceanographic structure,
resulting in restricted depositional/reworking processes. The sedimentary record, therefore,
underscores the significance of mass-transport processes in providing sediments to oceanic abyssal
plains as few other basins are able to do.
Olabarrieta, M, Warner, J.C., and Armstrong, B, 2012, Ocean-Atmosphere dynamics during Hurricane Ida and Nor'Ida: an application of the Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST) modeling system:
, v. 43-44
, pp. 112-137
. Online at 10.1016/j.ocemod.2011.12.008
The coupled oceanatmospherewavesediment transport (COAWST) modeling system was used to
investigate atmosphereoceanwave interactions in November 2009 during Hurricane Ida and its subsequent
evolution to NorIda, which was one of the most costly storm systems of the past two decades. One
interesting aspect of this event is that it included two unique atmospheric extreme conditions, a hurricane
and a noreaster storm, which developed in regions with different oceanographic characteristics.
Our modeled results were compared with several data sources, including GOES satellite infrared data,
JASON-1 and JASON-2 altimeter data, CODAR measurements, and wave and tidal information from the
National Data Buoy Center (NDBC) and the National Tidal Database. By performing a series of numerical
runs, we were able to isolate the effect of the interaction terms between the atmosphere (modeled with
Weather Research and Forecasting, the WRF model), the ocean (modeled with Regional Ocean Modeling
System (ROMS)), and the wave propagation and generation model (modeled with Simulating Waves
Nearshore (SWAN)). Special attention was given to the role of the ocean surface roughness. Three different
ocean roughness closure models were analyzed: DGHQ (which is based on wave age), TY2001 (which
is based on wave steepness), and OOST (which considers both the effects of wave age and steepness).
Including the ocean roughness in the atmospheric module improved the wind intensity estimation and
therefore also the wind waves, surface currents, and storm surge amplitude. For example, during the passage
of Hurricane Ida through the Gulf of Mexico, the wind speeds were reduced due to wave-induced
ocean roughness, resulting in better agreement with the measured winds. During NorIda, including
the wave-induced surface roughness changed the form and dimension of the main low pressure cell,
affecting the intensity and direction of the winds. The combined wave age- and wave steepness-based
parameterization (OOST) provided the best results for wind and wave growth prediction. However, the
best agreement between the measured (CODAR) and computed surface currents and storm surge values
was obtained with the wave steepness-based roughness parameterization (TY2001), although the differences
obtained with respect to DGHQ were not significant. The influence of sea surface temperature (SST)
fields on the atmospheric boundary layer dynamics was examined; in particular, we evaluated how the
SST affects wind wave generation, surface currents and storm surges. The integrated hydrograph and
integrated wave height, parameters that are highly correlated with the storm
Olabarrieta, Maitane, and Warner, John C., 2011, Wave-current interaction in Willapa Bay:
Journal of Geophysical Research - Oceans
, v. 116
, no. C12
. Online at 10.1029/2011JC007387
his paper describes the importance of wave-current interaction in an inlet-estuary system. The three-dimensional, fully coupled, Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system was applied in Willapa Bay (Washington State) from 22 to 29 October 1998 that included a large storm event. To represent the interaction between waves and currents, the vortex-force method was used. Model results were compared with water elevations, currents, and wave measurements obtained by the U.S. Army Corp of Engineers. In general, a good agreement between field data and computed results was achieved, although some discrepancies were also observed in regard to wave peak directions in the most upstream station. Several numerical experiments that considered different forcing terms were run in order to identify the effects of each wind, tide, and wave-current interaction process. Comparison of the horizontal momentum balances results identified that wave-breaking-induced acceleration is one of the leading terms in the inlet area. The enhancement of the apparent bed roughness caused by waves also affected the values and distribution of the bottom shear stress. The pressure gradient showed significant changes with respect to the pure tidal case. During storm conditions the momentum balance in the inlet shares the characteristics of tidal-dominated and wave-dominated surf zone environments. The changes in the momentum balance caused by waves were manifested both in water level and current variations. The most relevant effect on hydrodynamics was a wave-induced setup in the inner part of the estuary.
Poppe, L.J., McMullen, K.Y., Ackerman, S.D., Blackwood, D.S., Irwin, B.J., Schaer, J.D., and Forrest, M.R., 2011, Sea-Floor Geology and Character of Eastern Rhode Island Sound West of Gay Head, Massachusetts:
U. S. Geological Survey Open-File Report 2011-1004, DVD-Rom and online
. Online at http://pubs.usgs.gov/of/2011/1004/
Gridded multibeam bathymetry covers approximately 102 square kilometers of sea floor in eastern Rhode Island Sound west of Gay Head, Massachusetts. Although originally collected for charting purposes during National Oceanic and Atmospheric Administration hydrographic survey H11922, these acoustic data and the sea-floor stations subsequently occupied to verify them (1) show the composition and terrain of the seabed, (2) provide information on sediment transport and benthic habitat, and (3) are part of an expanding series of studies that provide a fundamental framework for research and management activities (for example, windfarms and fisheries) along the Massachusetts inner continental shelf.
Most of the sea floor in the study area has an undulating to faintly rippled appearance and is composed of bioturbated muddy sand, reflecting processes associated with sediment sorting and reworking. Shallower areas are composed of rippled sand and, where small fields of megaripples are present, indicate sedimentary environments characterized by processes associated with coarse bedload transport. Boulders and gravel were found on the floors of scour depressions and on top of an isolated bathymetric high where erosion has removed the Holocene marine sediments and exposed the underlying relict lag deposits of Pleistocene drift. The numerous scour depressions, which formed during storm-driven events, result in the juxtaposition of sea-floor areas with contrasting sedimentary environments and distinct gravel, sand, and muddy sand textures. This textural heterogeneity in turn creates a complex patchwork of habitats. Our observations of local variations in community structure suggest that this small-scale textural heterogeneity adds dramatically to the sound-wide benthic biological diversity.
Poppe, L.J., McMullen, K.Y., Ackerman, S.D., Blackwood, D.S., Shaer, J.D., Forrest, M.R., Ostapenko, A.J., and Doran, E.F., 2011, Sea-floor geology and topography, offshore in eastern Long Island Sound:
U.S. Geological Survey Open-File Report 2010-1150
. Online at http://pubs.usgs.gov/of/2010/1150/
A gridded multibeam bathymetric dataset covers approximately 133.7 square kilometers of sea floor offshore in eastern Long Island Sound. Although originally collected for charting purposes during National Oceanic and Atmospheric Administration hydrographic survey H11997, these acoustic data, and the sea-floor sampling and photography stations subsequently occupied to verify them during USGS cruise 2010-015-FA, are part of an expanding series of studies that provide a fundamental framework for research and resource management (for example, cables, pipelines, and dredging) activities in this major East Coast estuary. Results show the composition and terrain of the seabed and provide information on sediment transport and benthic habitat. Bedrock outcrops, erosional outliers, lag deposits of boulders, scour depressions, and extensive gravel pavements are common in the eastern part of the study area. These features, which result from the near-constant exposure to strong tidal currents, indicate sedimentary environments dominated by processes associated with erosion. Large fields of transverse and barchanoid sand waves in the western part of the study area reflect slightly lower energy levels and sedimentary environments where processes associated with coarse bedload transport prevail.
Poppe, L.J., Williams, S.J., and Babb, I.G., 2011, Character of shell beds flanking Herod Point Shoal, southeastern Long Island Sound, New York:
Journal of Coastal Research
, v. 27
, no. 3
, pp. 493-501
. Online at 10.2112/JCOASTRES-D-09-00079.1
High biogenic productivity, strong tidal currents, shoal topography, and short transport distances combine to favor shell-bed formation along the lower flanks of a cape-associated shoal off Herod Point on Long Island, New York. This shell bed has a densely packed, clast-supported fabric composed largely of undegraded surf clam (Spisula solidissima) valves. It is widest along the central part of the western flank of the shoal where topographic gradients are steep and a stronger flood tide results in residual flow. The bed is narrower and thinner toward the landward margins where currents are too weak to transport larger valves and topographic gradients are gentle, limiting bed-load transport mechanisms by which the shells are concentrated.
Reconnaissance mapping off Roanoke Point suggests that shell beds are also present at the other cape-associated shoals off northeastern Long Island, where relatively similar geomorphic and oceanographic conditions exist. These shell beds are important to the Long Island Sound ecosystem because they provide complex benthic habitats of rough and hard substrates at the boundary between the muddy basin floor and mobile sand of the shoals.
Scandella, B., Varadharajan, C., Hemond, H., Ruppel, C., and Juanes, R, 2011, A conduit dilation model of methane venting from lake sediments:
Geophysical Research Letters
, v. 38
, no. 6
Methane is a potent greenhouse gas, but its effects on Earth's climate remain poorly constrained, in part due to uncertainties in global methane fluxes to the atmosphere. An important source of atmospheric methane is the methane generated in organic-rich sediments underlying surface water bodies, including lakes, wetlands, and the ocean. The fraction of the methane that reaches the atmosphere depends critically on the mode and spatiotemporal characteristics of free-gas venting from the underlying sediments. Here we propose that methane transport in lake sediments is controlled by dynamic conduits, which dilate and release gas as the falling hydrostatic pressure reduces the effective stress below the tensile strength of the sediments. We test our model against a four-month record of hydrostatic load and methane flux in Upper Mystic Lake, Mass., USA, and show that it captures the complex episodicity of methane ebullition. Our quantitative conceptualization opens the door to integrated modeling of methane transport to constrain global methane release from lakes and other shallow-water, organic-rich sediment systems, and to assess its climate feedbacks.
Scanlon, K.M., Waller, R.G., and Robinson, L., 2011, Cold-Water Coral Distributions in the Drake Passage Area from Towed Camera Observations Initial Interpretations:
, v. 6
, no. 1
. Online at 10.1371/journal.pone.0016153
Seamounts are unique deep-sea features that create habitats thought to have high levels of endemic fauna, productive fisheries and benthic communities vulnerable to anthropogenic impacts. Many seamounts are isolated features, occurring in the high seas, where access is limited and thus biological data scarce. There are numerous seamounts within the Drake Passage (Southern Ocean), yet high winds, frequent storms and strong currents make seafloor sampling particularly difficult. As a result, few attempts to collect biological data have been made, leading to a paucity of information on benthic habitats or fauna in this area, particularly those on primarily hard-bottom seamounts and ridges. During a research cruise in 2008 six locations were examined (two on the Antarctic margin, one on the Shackleton Fracture Zone, and three on seamounts within the Drake Passage), using a towed camera with onboard instruments to measure conductivity, temperature, depth and turbidity. Dominant fauna and bottom type were categorized from 200 randomized photos from each location. Cold-water corals were present in high numbers in habitats both on the Antarctic margin and on the current swept seamounts of the Drake Passage, though the diversity of orders varied. Though the Scleractinia (hard corals) were abundant on the sedimented margin, they were poorly represented in the primarily hard-bottom areas of the central Drake Passage. The two seamount sites and the Shackleton Fracture Zone showed high numbers of stylasterid (lace) and alcyonacean (soft) corals, as well as large numbers of sponges. Though data are preliminary, the geological and environmental variability (particularly in temperature) between sample sites may be influencing cold-water coral biogeography in this region. Each area observed also showed little similarity in faunal diversity with other sites examined for this study within all phyla counted. This manuscript highlights how little is understood of these isolated features, particularly in Polar regions.
Socolofsky, S.A., Adams, E.E., Sherwood, C.R, 2011, Formation dynamics of subsurface hydrocarbon intrusions following the Deepwater Horizon blowout:
Geophysical Research Letters
, v. 38
, no. L09602
, pp. 6
. Online at 10.1029/2011GL047174
Hydrocarbons released following the Deepwater
Horizon (DH) blowout were found in deep, subsurface horizontal
intrusions, yet there has been little discussion about
how these intrusions formed. We have combined measured
(or estimated) observations from the DH release with empirical
relationships developed from previous lab experiments
to identify the mechanisms responsible for intrusion formation
and to characterize the DH plume. Results indicate that
the intrusions originate from a stratification‐dominated multiphase
plume characterized by multiple subsurface intrusions
containing dissolved gas and oil along with small
droplets of liquid oil. Unlike earlier lab measurements, where
the potential density in ambient water decreased linearly with
elevation, at the DH site it varied quadratically. We have
modified our method for estimating intrusion elevation under
these conditions and the resulting estimates agree with observations
that the majority of the hydrocarbons were found
between 800 and 1200 m. Citation: Socolofsky, S. A., E. E.
Adams, and C. R. Sherwood (2011), Formation dynamics of subsurface
hydrocarbon intrusions following the Deepwater Horizon
blowout, Geophys. Res. Lett., 38, L09602, 10.1029/
Thieler, E.R, and Hapke, C.J., 2011, USGS Science for the Nation's Changing Coasts: Shoreline Change Assessment:
U. S. Geological Survey Fact Sheet 2011-3074
. Online at http://pubs.usgs.gov/fs/2011/3074/
Valentine, Page C., Gallea, Leslie B., Blackwood, Dann S., and Twomey, Erin R., 2010, Seabed photographs, sediment texture analyses, and sun-illuminated sea floor topography in the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts:
U.S. Geological Survey Data Series 469
. Online at http://pubs.usgs.gov/ds/469/
The U.S. Geological Survey, in collaboration with National Oceanic and Atmospheric Administrations National Marine Sanctuary Program, conducted seabed mapping and related research in the Stellwagen Bank National Marine Sanctuary region from 1993 to 2004. The mapped area is approximately 3,700 km² (1,100 nmi²) in size and was subdivided into 18 quadrangles. An extensive series of sea-floor maps of the region based on multibeam sonar surveys has been published as paper maps and online in digital format (PDF, EPS, PS). In addition, 2,628 seabed-sediment samples were collected and analyzed and are in the usSEABED: Atlantic Coast Offshore Surficial Sediment Data Release. This report presents for viewing and downloading the more than 10,600 still seabed photographs that were acquired during the project. The digital images are provided in thumbnail, medium (1536 x 1024 pixels), and high (3071 x 2048) resolution. The images can be viewed by quadrangle on the U.S. Geological Survey Woods Hole Coastal and Marine Science Centers photograph database. Photograph metadata are embedded in each image in Exchangeable Image File Format and also provided in spreadsheet format. Published digital topographic maps and descriptive text for seabed features are included here for downloading and serve as context for the photographs. An interactive topographic map for each quadrangle shows locations of photograph stations, and each location is linked to the photograph database. This map also shows stations where seabed sediment was collected for texture analysis; the results of grain-size analysis and associated metadata are presented in spreadsheet format.
Voulgaris, G., Kumar, N., and Warner, J.C., 2011, A methodology for the prediction of rip currents using a 3-D numerical, coupled, wave-current model:
1st International Rip Current Symposium Conference Proceedings
, pp. 87-105
. Online at 10.1201/b10916-6