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At least 397 records · Page 22Linked to original sources

Contaminated sediments database for Long Island Sound and the New York Bight

The Contaminated Sediments Database for Long Island Sound and the New York Bight provides a compilation of published and unpublished sediment texture and contaminant data. This report provides maps of several of the contaminants in the database as well as references and a section on using the data to assess the environmental status of these coastal areas. The database contains information collected between 1956-1997; providing an historical foundation for future contaminant studies in the region.

Open-File Report↗

High-resolution chirp and mini-sparker seismic-reflection data from the southern California continental shelf — Gaviota to Mugu Canyon

The U.S. Geological Survey (USGS) collected high-resolution shallow seismic-reflection data in September, 2007, and June-July, 2008, from the continental shelf offshore of southern California between Gaviota and Mugu Canyon, in support of the California's State Waters Mapping Program. Data were acquired using SIG 2mille mini-sparker and Edgetech chirp 512 instruments aboard the R/V Zephyr (Sept. 2007) and R/V Parke Snavely (June-July 2008). The survey area spanned approximately 120 km of coastline, and included shore-perpendicular transects spaced 1.0-1.5 km apart that extended offshore to at least the 3-mile limit of State waters, in water depths ranging from 10 m near shore to 300 m near the offshore extent of Mugu and Hueneme submarine canyons. Subbottom acoustic penetration spanned tens to several hundred meters, variable by location. This report includes maps of the surveyed transects, linked to Google Earth software, as well as digital data files showing images of each transect in SEG-Y, JPEG, and TIFF formats. The images of sediment deposits, tectonic structure, and natural-gas seeps collected during this study provide geologic information that is essential to coastal zone and resource management at Federal, State and local levels, as well as to future research on the sedimentary, tectonic, and climatic record of southern California.

California↗

High-resolution seismic-reflection and marine-magnetic data from offshore central California--San Gregorio to Point Sur

The U.S. Geological Survey collected high-resolution seismic-reflection data on four surveys (S-N1-09-MB, S-15-10-NC, S-06-11-MB, and S-04-12-MB) and marine-magnetic data on one survey (S-06-11-MB) between 2009 and 2012, offshore of central California between San Gregorio and Point Sur. This work was supported in part by the California Seafloor Mapping Program. The survey areas span about 120 km of California's coast (including Monterey Bay). Most data were collected aboard the U.S. Geological Survey R/V Parke Snavely. Cumulatively, approximately 1,410 km of single-channel seismic-reflection data were acquired, mainly using a SIG 2mille minisparker. About 44 km of data were collected simultaneously using an EdgeTech Chirp 512. Subbottom acoustic penetration spanned tens to several hundreds of meters, variable by location. Marine magnetic data were collected on approximately 460 km of track lines (mainly in southern Monterey Bay) using a Geometrics G882 cesium-vapor marine magnetometer. This report includes maps and navigation files of the surveyed transects, linked to Google Earth™ software, as well as digital data files showing images of each transect in SEG-Y and JPEG formats. The images of bedrock, sediment deposits, and tectonic structure provide geologic information that is essential to hazard assessment, regional sediment management, and coastal and marine spatial planning at Federal, State and local levels, as well as to future research on the geomorphic, sedimentary, tectonic, and climatic record of central California.

California↗

Water-quality monitoring strategy for Mount Hope Bay and the Taunton River Estuary, southeastern Massachusetts

The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection (MassDEP), began a study in 2018 to develop a water-quality monitoring strategy (WQMS) for Mount Hope Bay and the Taunton River Estuary in southeastern Massachusetts. MassDEP is interested in water-quality data in Mount Hope Bay and the Taunton River Estuary to characterize current water-quality conditions, assess nutrient-related effects, and capture conditions before and after planned upgrades to wastewater treatment facilities. The WQMS provides an overview of the environmental setting of Mount Hope Bay and the Taunton River Estuary and of dissolved oxygen and nutrient-related water-quality issues, reviews historical and existing monitoring data, and provides recommendations for future monitoring designed to meet five MassDEP management objectives: (1) support MassDEP’s review of coastal and marine dissolved oxygen criteria, (2) assess conditions within MassDEP waterbody assessment units in Mount Hope Bay and the Taunton River Estuary with respect to selected criteria in the Massachusetts Surface Water Quality Standards, (3) assess conditions along the freshwater/saltwater interface (salt wedge) of the Taunton River Estuary and delineate the boundary between the freshwater and saltwater waterbody assessment units, (4) estimate data requirements needed to determine nutrient loads flowing into Mount Hope Bay and the Taunton River Estuary, and (5) evaluate data requirements needed to support hydrodynamic and water-quality models for Mount Hope Bay and the Taunton River Estuary. This WQMS may be used by MassDEP to develop a statewide approach for monitoring estuaries in Massachusetts.

Massachusetts↗

Food selection among Atlantic Coast seaducks in relation to historic food habits

Food selection among Atlantic Coast seaducks during 1999-2005 was determined from hunter-killed ducks and compared to data from historic food habits file (1885-1985) for major migrational and wintering areas in the Atlantic Flyway. Food selection was determined by analyses of the gullet (esophagus and proventriculus) and gizzard of 860 ducks and summarized by aggregate percent for each species. When sample size was adequate comparisons were made among age and sex groupings and also among local sites in major habitat areas. Common eiders in Maine and the Canadian Maritimes fed predominantly (53%) on the blue mussel (Mytilus edulis). Scoters in Massachusetts, Maine, and the Canadian Maritimes fed predominantly on the blue mussel (46%), Atlantic jackknife clam (Ensis directus; 19%), and Atlantic surf clam (Spisula solidissima; 15%), whereas scoters in the Chesapeake Bay fed predominantly on hooked mussel (Ischadium recurvum; 42%), the stout razor clam (Tagelus plebeius; 22%), and dwarf surf clam (Mulinia lateralis; 15%). The amethyst gem clam (Gemma gemma) was the predominant food (45%) of long-tailed ducks in Chesapeake Bay. Buffleheads and common goldeneyes fed on a mixed diet of mollusks and soft bodied invertebrates (amphipods, isopods and polychaetes). No major differences were noticed between the sexes in regard to food selection in any of the wintering areas. Comparisons to historic food habits in all areas failed to detect major differences. However, several invertebrate species recorded in historic samples were not found in current samples and two invasive species (Atlantic Rangia, Rangia cuneata and green crab, Carcinas maenas) were recorded in modem samples, but not in historic samples. Benthic sampling in areas where seaducks were collected showed a close correlation between consumption and availability. Each seaduck species appears to fill a unique niche in regard to feeding ecology, although there is much overlap of prey species selected. Understanding the trophic relationships of seaducks in coastal wintering areas will give managers a better understanding of habitat changes in regard to future environmental perturbations.

Book chapter↗

A study of the 2015 Mw 8.3 Illapel earthquake and tsunami: Numerical and analytical approaches

The September 16, 2015 Illapel, Chile earthquake triggered a large tsunami, causing both economic losses and fatalities. To study the coastal effects of this earthquake, and to understand how such hazards might be accurately modeled in the future, different finite fault models of the Illapel rupture are used to define the initial condition for tsunami simulation. The numerical code Non-hydrostatic Evolution of Ocean WAVEs (NEOWAVE) is employed to model the tsunami evolution through the Pacific Ocean. Because only a short time is available for emergency response, and since the earthquake and tsunami sources are close to the coast, gaining a rapid understanding of the near-field run-up behavior is highly relevant to Chile. Therefore, an analytical solution of the 2 ? 1 D shallow water wave equations is considered. With this solution, we show that we can quickly estimate the run-up distribution along the coastline, to first order. After the earthquake and tsunami, field observations were measured in the surrounded coastal region, where the tsunami resulted in significant run-up. First, we compare the analytical and numerical solutions to test the accuracy of the analytical approach and the field observations, implying the analytic approach can accurately model tsunami run-up after an earthquake, without sacrificing the time necessary for a full numerical inversion. Then, we compare both with field run-up measurements. We observe the consistency between the two approaches. To complete the analysis, a tsunami source inversion is performed using run-up field measurements only. These inversion results are compared with seismic models, and are shown to capture the broad-scale details of those models, without the necessity of the detailed data sets they invert.

Illapel↗

Proceedings of a Coastal and Marine Spatial Planning Workshop for the Western United States

Recent scientific and ocean policy assessments demonstrate that a fundamental change in our current management system is required to achieve the long-term health of our ocean, coasts, and Great Lakes in order to sustain the services and benefits they provide to society. The present (2011) species- and sector-centric way we manage these ecosystems cannot account properly for cumulative effects, sustaining multiple ecosystem services, and holistically and explicitly evaluating the tradeoffs associated with proposed alternative and multiple human uses. A transition to an ecosystem-based approach to management and conservation of coastal and marine resources is needed. Competing uses and activities such as commerce, recreation, cultural practices, energy development, conservation, and national security are increasing pressure for new and expanded resource usage in coastal marine ecosystems. Current management efforts use a sector-by-sector approach that mostly focuses on a limited range of tools and outcomes [for example, oil and gas leases, fishery management plans, and Marine Protected Areas (MPAs)]. A comprehensive, ecosystem-based, and proactive approach to planning and managing these uses and activities is needed. Further, scientific understanding and information are essential to achieve an integrated decision-making process that includes knowledge of ecosystem services, existing and possible future conditions, and potential consequences of natural and anthropogenic events. Because no single government agency has executive authority for coastal or ocean resources, conflicting objectives around competing uses abound. In recent years, regional- and state-level initiatives in Coastal and Marine Spatial Planning (CMSP) have emerged to coordinate management activities. In some respects, the components and steps of the overall CMSP process are similar to how existing ocean resources are regulated and managed. For example, the Bureau of Ocean Energy Management Regulation and Enforcement (BOEMRE) uses spatial planning exercises in State Renewable Energy Task Force meetings to identify competing and conflicting ocean uses, and to delineate areas suitable for renewable energy development. Similarly terrestrial areas such as in national parks and national wildlife refuges managed by the Department of the Interior (DOI) prepare management plans for preservation and restoration of species and habitats of concern, some of which are protected by law. The analogy to CMSP is clear - multiple users and multiple expectations, resulting in the requirement to establish spatial plans for management of different resources and different ecosystem services. A two-day workshop on December 1-2, 2010, was convened for DOI representatives and several key non-DOI participants with roles in CMSP as a step toward clarifying national perspectives and consequences of the National Ocean Policy for the West (appendix 1). Discussions helped to develop an understanding of CMSP from the federal perspective and to identify regional priorities. An overarching theme was to promote a better understanding of current and future science needs. The workshop format included briefings by key Federal agencies on their understanding of the national focus followed by discussion of regional issues, including the needs for scientific information and coordination. The workshop also explored potential science contributions by Federal agencies and others; utilizing current capabilities, data, and information systems; and provided a foundation for possible future regional workshops focusing in turn on the West Coast Region (California, Oregon, and Washington), Pacific Islands (sometimes referred to as Oceania) and Alaska. Participants were asked to share information in the following areas, recognizing that the purpose would be to learn more about the national perspective (see appendixes 2-4): Explore how the Western U.S. (Alaska, Pacific Islands, and West Coast Region) migh

Open-File Report↗

Simulation and Particle-Tracking Analysis of Selected Ground-Water Pumping Scenarios at Vogtle Electric Generation Plant, Burke County, Georgia

The source of ground water to production wells at Vogtle Electric Generation Plant (VEGP), a nuclear power plant in Burke County, Georgia, was simulated under existing (2002) and potential future pumping conditions using an existing U.S. Geological Survey (USGS) MODFLOW ground-water flow model of a 4,455-square-mile area in the Coastal Plain of Georgia and South Carolina. Simulation results for three steady-state pumping scenarios were compared to each other and to a 2002 Base Case condition. The pumping scenarios focused on pumping increases at VEGP resulting from projected future demands and the addition of two electrical-generating reactor units. Scenarios simulated pumping increases at VEGP ranging from 1.09 to 3.42 million gallons per day (Mgal/d), with one of the scenarios simulating the elimination of 5.3 Mgal/d of pumping at the Savannah River Site (SRS), a U.S. Department of Energy facility located across the Savannah River from VEGP. The largest simulated water-level changes at VEGP were for the scenario whereby pumping at the facility was more than tripled, resulting in drawdown exceeding 4-8 feet (ft) in the aquifers screened in the production wells. For the scenario that eliminated pumping at SRS, water-level rises of as much as 4-8 ft were simulated in the same aquifers at SRS. Results of MODFLOW simulations were analyzed using the USGS particle-tracking code MODPATH to determine the source of water and associated time of travel to VEGP production wells. For each of the scenarios, most of the recharge to VEGP wells originated in an upland area near the county line between Burke and Jefferson Counties, Georgia, with none of the recharge originating on SRS or elsewhere in South Carolina. An exception occurs for the scenario whereby pumping at VEGP was more than tripled. For this scenario, some of the recharge originates in an upland area in eastern Barnwell County, South Carolina. Simulated mean time of travel from recharge areas to VEGP wells for the Base Case and the three other pumping scenarios was between about 2,700 and 3,800 years, with some variation related to changes in head gradients because of pumping changes.

Georgia↗

Evidence for earthquake triggering of large landslides in coastal Oregon, USA

Landslides are ubiquitous along the Oregon coast. Many are large, deep slides in sedimentary rock and are dormant or active only during the rainy season. Morphology, observed movement rates, and total movement suggest that many are at least several hundreds of years old. The offshore Cascadia subduction zone produces great earthquakes every 300–500 years that generate tsunami that inundate the coast within minutes. Many slides and slide-prone areas underlie tsunami evacuation and emergency response routes. We evaluated the likelihood of existing and future large rockslides being triggered by pore-water pressure increase or earthquake-induced ground motion using field observations and modeling of three typical slides. Monitoring for 2–9 years indicated that the rockslides reactivate when pore pressures exceed readily identifiable levels. Measurements of total movement and observed movement rates suggest that two of the rockslides are 296–336 years old (the third could not be dated). The most recent great Cascadia earthquake was M 9.0 and occurred during January 1700, while regional climatological conditions have been stable for at least the past 600 years. Hence, the estimated ages of the slides support earthquake ground motion as their triggering mechanism. Limit-equilibrium slope-stability modeling suggests that increased pore-water pressures could not trigger formation of the observed slides, even when accompanied by progressive strength loss. Modeling suggests that ground accelerations comparable to those recorded at geologically similar sites during the M 9.0, 11 March 2011 Japan Trench subduction-zone earthquake would trigger formation of the rockslides. Displacement modeling following the Newmark approach suggests that the rockslides would move only centimeters upon coseismic formation; however, coseismic reactivation of existing rockslides would involve meters of displacement. Our findings provide better understanding of the dynamic coastal bluff environment and hazards from future subduction-zone earthquakes.

Oregon↗

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

The loss of coastal marshes is a topic of great concern, because these habitats provide tangible ecosystem services and are at risk from sea-level rise and human activities. In recent years, significant effort has gone into understanding and modeling the relationships between the biological and physical factors that contribute to marsh stability. Simulation-based process models suggest that marsh stability is the product of a complex feedback between sediment supply, flooding regime and vegetation response, resulting in elevation gains sufficient to match the combination of relative sea-level rise and losses from erosion. However, there have been few direct, empirical tests of these models, because long-term datasets that have captured sufficient numbers of marsh loss events in the context of a rigorous monitoring program are rare. We use a multi-year data set collected by the Coastwide Reference Monitoring System (CRMS) that includes transitions of monitored vegetation plots to open water to build and test a predictive model of near-term marsh vulnerability. We found that despite the conclusions of previous process models, elevation change had no ability to predict the transition of vegetated marsh to open water. However, we found that the processes that drive elevation change were significant predictors of transitions. Specifically, vegetation cover in prior year, land area in the surrounding 1 km2 (an estimate of marsh fragmentation), and the interaction of tidal amplitude and position in tidal frame were all significant factors predicting marsh loss. This suggests that 1) elevation change is likely better a predictor of marsh loss at time scales longer than we consider in this study and 2) the significant predictive factors affect marsh vulnerability through pathways other than elevation change, such as resistance to erosion. In addition, we found that, while sensitivity of marsh vulnerability to the predictive factors varied spatially across coastal Louisiana, vegetation cover in prior year was the best single predictor of subsequent loss in most sites followed by changes in percent land and tidal amplitude. The model’s predicted land loss rates correlated well with land loss rates derived from satellite data, although agreement was spatially variable. These results indicate 1) monitoring the loss of small scale vegetation plots can inform patterns of land loss at larger scales 2) the drivers of land loss vary spatially across coastal Louisiana, and 3) relatively simple models have potential as highly informative tools for bioassessment, directing future research, and management planning.

Louisiana↗

Ecological transformations of coastal wetlands of the conterminous United States in response to contemporaneous sea-level rise

Coastal wetlands are among the most important ecosystems on the planet but are increasingly imperiled by accelerating sea-level rise (SLR). In the past, biogeomorphic feedbacks have allowed coastal wetlands to adjust vertically and persist through periods of accelerated SLR. Recent rates of SLR are faster than any in recent geologic history, making the fate of coastal wetlands highly uncertain. Here, we synthesize surface elevation table marker-horizon data from 442 stations in coastal wetlands across the conterminous United States to evaluate if they are largely persisting in the face of accelerated SLR, or if they are undergoing ecological transformations of submergence and/or migration. Across the conterminous United States, 11% of coastal wetlands in this sample are on a trajectory of submergence whereas 73% of sites are lagging SLR, but may be able to migrate upslope, and 16% of sites are gaining elevation at rates which exceed SLR indicating persistence and an ability to migrate seaward. Vulnerability of these systems to ecological transformation varies across the three coasts of the conterminous United States which, span large biogeomorphic gradients. These results serve as one of the first national syntheses of coastal wetland elevation trends and may help focus conservation and restoration efforts in a rapidly changing future.

conterminous United States↗

Macroclimatic change expected to transform coastal wetland ecosystems this century

Coastal wetlands, existing at the interface between land and sea, are highly vulnerable to climate change. Macroclimate (for example, temperature and precipitation regimes) greatly influences coastal wetland ecosystem structure and function. However, research on climate change impacts in coastal wetlands has concentrated primarily on sea-level rise and largely ignored macroclimatic drivers, despite their power to transform plant community structure and modify ecosystem goods and services. Here, we model wetland plant community structure based on macroclimate using field data collected across broad temperature and precipitation gradients along the northern Gulf of Mexico coast. Our analyses quantify strongly nonlinear temperature thresholds regulating the potential for marsh-to-mangrove conversion. We also identify precipitation thresholds for dominance by various functional groups, including succulent plants and unvegetated mudflats. Macroclimate-driven shifts in foundation plant species abundance will have large effects on certain ecosystem goods and services. Based on current and projected climatic conditions, we project that transformative ecological changes are probable throughout the region this century, even under conservative climate scenarios. Coastal wetland ecosystems are functionally similar worldwide, so changes in this region are indicative of potential future changes in climatically similar regions globally.

Nature Climate Change↗

Long-term nutrient reductions lead to the unprecedented recovery of a temperate coastal region

Human actions, including nutrient pollution, are causing the widespread degradation of coastal habitats, and efforts to restore these valuable ecosystems have been largely unsuccessful or of limited scope. We provide an example of successful restoration linking effective management of nutrients to the successful recovery of submersed aquatic vegetation along thousands of kilometers of coastline in Chesapeake Bay, United States. We also show that biodiversity conservation can be an effective path toward recovery of coastal systems. Our study validates 30 years of environmental policy and provides a road map for future ecological restoration.

Chesapeake Bay watershed↗

The Imperial Valley of California is critical to wintering Mountain Plovers

We surveyed Mountain Plovers ( Charadrius montanus ) wintering in the Imperial Valley of California in January 2001, and also recorded the types of crop fields used by plovers in this agricultural landscape. We tallied 4037 plovers in 36 flocks ranging in size from 4 to 596 birds. Plovers were more common on alfalfa and Bermudagrass fields than other field types. Further, most birds were on alfalfa fields that were currently being (or had recently been) grazed, primarily by domestic sheep. Plovers used Bermudagrass fields only after harvest and subsequent burning. Examination of Christmas Bird Count data from 1950–2000 indicated that the Mountain Plover has abandoned its historical wintering areas on the coastal plains of California. Numbers in the Central Valley seem to have undergone recent declines also. We believe that the cultivated landscape of the Imperial Valley provides wintering habitats for about half of the global population of Mountain Plovers. We attribute the current importance of the Imperial Valley for Mountain Plovers to loss of native coastal and Central Valley habitats rather than to a behavioral switching of wintering areas through time. Future changes in specific cropping or management practices in the Imperial Valley will have a major impact on the conservation status of this species.

Journal of Field Ornithology↗

Preface to book: Wetland carbon and environmental management

The idea for this book, including its organization and contents, has its origin in the latest environmental and climate policy requirements in the United States, as well as science advances. In 2007, the U.S. Congress passed the Energy Independence and Security Act (EISA), from which Section 712 required U.S. Federal agencies to provide a better understanding of carbon and greenhouse gas fluxes across the United States. As a result, largescale and coordinated efforts were launched to assess carbon storage, carbon fluxes, and greenhouse gas fluxes including CO2, CH4, and N2O from all major terrestrial and freshwater aquatic ecosystems, including forest, grassland/shrub, agricultural lands, wetlands, and rivers, streams, lakes, and impoundments. The EISA assessment produced major results (Selmants et al., 2017; Zhu, 2011; Zhu & McGuire, 2016; Zhu & Reed, 2012, 2014), but recognized that wetlands remained a significant source of uncertainty, especially for those wetlands that were being actively managed. The more recent Second State of the Carbon Cycle Report by the U.S. Global Change Research Program (USGCRP), which devoted two separate chapters to inland and coastal wetlands, respectively, noted that large knowledge gaps still remain, ranging from inadequate analysis of restored and managed wetlands, and consequences of management decisions, to future wetland responses to climate change (USGCRP, 2018). In recent literature, wetland management is suggested as a potential natural solution to mitigate climate change (Fargione et al., 2018, Kroeger et al., 2017) and help offset direct losses of wetlands from sea level rise, subsidence, and coastal erosion (Wang et al., 2017). The recognition that a synthesis of wetland carbon management was urgently needed was the genesis of Wetland Carbon and Environmental Management; discerning the relationships between wetland management and carbon flux (loss or gain) is an international goal.

Geophysical Monograph Series↗

Geochemistry of sediments from coastal marshes of Louisiana

As a part of the U.S. Geological Survey Global Change and Climate History Program we have been studying the biogeochemistry of coastal marshes in Terrebonne Basin, Louisiana. Louisiana has about 40 percent of the coastal wetlands in the conterminous U.S. and it is losing wetlands at one of the highest rates in the U.S. with the conversion of about 65 km2/yr of marsh to open water (Britsch and Dunbar, 1993). The losses have been attributed to human and natural causes including saltwater intrusion through man-made canals, reduced sediment input, and regional subsidence. The net effect of these influences is to change the salinity of interior marshes in a fashion similar to a eustatic sea level rise. We are studying the cycling of carbon, sulfur, and other elements in sediments, waters, and marsh macrophytes in fresh, intermediate/brackish, and saltwater marshes in order to better understand how sea level rise, one aspect of global change, will influence and in turn be influenced by cycling of these elements. By characterizing the critical biogeochemical processes and the recent past environments in these rapidly changing marshes, we can improve predictions of future changes and interpretations of the historic geologic record in similar environments. In this report we describe our coastal marsh study sites in Louisiana, the types of samples collected, the collection methods, the chemical analysis methods, and selected chemical analysis results. Also included are summaries of the project quality control results. The raw chemical analysis results are provided in this report without interpretation. Interpretations will be provided in subsequent reports.

Louisiana↗