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

    Science.gov (United States)

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

    2015-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-02-15

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

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

    Science.gov (United States)

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

    2008-01-01

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

  4. Cytochrome P450 and organochlorine contaminants in black-crowned night-herons from the Chesapeake Bay region, USA

    Science.gov (United States)

    Rattner, B.A.; Melancon, M.J.; Rice, C.P.; Riley, W.; Eisemann, J.; Hines, R.K.

    1997-01-01

    Black-crowned night-heron (Nycticorax nycticorax) offspring were collected from a relatively uncontaminated coastal reference site (next to Chincoteague National Wildlife Refuge, VA, USA) and two sites in the Chesapeake Bay watershed (Baltimore Harbor, MD and Rock Creek Park, Washington, DC, USA). Hepatic microsomal activities of benzyloxyresorufin-O-dealkylase and ethoxyresorufin-O-dealkylase were significantly elevated (up to sixfold and ninefold induction, respectively) in pipping embryos from the Baltimore Harbor colony compared to the reference site, whereas values in embryos from the Rock Creek Park colony were intermediate. Concentrations of organochlorine pesticides and metabolites in pipping embryos from both sites in the Chesapeake watershed were greater than at the reference site but below the known threshold for reproductive impairment. However, concentrations of 10 arylhydrocarbon receptor-active polychlorinated biphenyl (PCB) congeners and estimated toxic equivalents were up to 37-fold greater in embryos collected from these two sites in the Chesapeake Bay region, with values for toxic congeners 77 and 126 exceeding those observed in pipping heron embryos from the Great Lakes. Monooxygenase activity of pipping embryos was associated with concentrations of several organochlorine pesticides, total PCBs, arylhydrocarbon receptor-active PCB congeners, and toxic equivalents (r = 0.30-0.59), providing further evidence of the value of cytochrome P450 as a biomarker of organic contaminant exposure. Organochlorine contaminant levels were greater in 10-d-old nestlings from Baltimore Harbor than the reference site but had no apparent effect on monooxygenase activity or growth. These findings demonstrate induction of cytochrome P450 in pipping black-crowned night-heron embryos in the Chesapeake Bay region, probably by exposure to PCB congeners of local origin, and the accumulation of organochlorine pesticides and metabolites in nestling herons from Baltimore

  5. Species-specific accumulation of polybrominated diphenyl ether flame retardants in birds of prey from the Chesapeake Bay region, USA

    Energy Technology Data Exchange (ETDEWEB)

    Chen Da, E-mail: chen@vims.ed [Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Hale, Robert C. [Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Watts, Bryan D. [Center for Conservation Biology, College of William and Mary, Williamsburg, VA 23185 (United States); La Guardia, Mark J.; Harvey, Ellen [Department of Environmental and Aquatic Animal Health, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA 23062 (United States); Mojica, Elizabeth K. [Center for Conservation Biology, College of William and Mary, Williamsburg, VA 23185 (United States)

    2010-05-15

    Compared to organochlorines, little is known about polybrominated diphenyl ether (PBDE) contamination of birds of prey breeding in the Chesapeake Bay, the largest estuary in the U.S. This study examined and compared PBDE contamination in eggs of osprey, double-crested cormorant, brown pelican and peregrine falcon from this area. Several legacy persistent organic pollutants such as PCBs and DDE were also investigated. The level of urbanization of the landscape appeared to influence the level of PBDE exposure. PBDE congener distribution patterns varied between piscivorous and terrestrial-feeding birds. This suggests individual congeners may be subject to differences in bioaccumulation, biomagnification or metabolism in the aquatic and terrestrial food webs. Biomagnification of PBDEs was studied in the Bay aquatic food chains for the first time. A biomagnification factor of 25.1 was estimated for SIGMAPBDEs for the fish - osprey egg food chain. Hazard quotients, applied as a preliminary evaluation, indicated that PBDEs may pose a moderate hazard to ospreys and peregrine falcons through impairment of reproductive performance. - Birds of prey breeding in the Chesapeake Bay (USA) exhibited species-specific PBDE accumulation patterns.

  6. The deep biosphere in terrestrial sediments in the Chesapeake Bay area, Virginia, USA

    Directory of Open Access Journals (Sweden)

    Anja eBreuker

    2011-07-01

    Full Text Available For the first time quantitative data on the abundance of Bacteria, Archaea and Eukarya in deep terrestrial sediments are provided using multiple methods (total cell counting, quantitative real-time PCR (Q-PCR and catalyzed reporter deposition – fluorescence in situ hybridization (CARD-FISH. The oligotrophic (organic carbon content of ~ 0.2 % deep terrestrial sediments in the Chesapeake Bay area at Eyreville, Virginia, USA, were drilled and sampled up to a depth of 140 m in 2006. The possibility of contamination during drilling was checked using fluorescent microspheres. Total cell counts decreased from 109 to 106 cells per g dry weight (dw within the uppermost 20 m depth, and did not further decrease with depth below. A significant proportion of the total cell counts could be detected with CARD-FISH within the uppermost 7 m depth. The CARD-FISH numbers for Bacteria were about an order of magnitude higher than those for Archaea. The dominance of Bacteria over Archaea was confirmed by Q-PCR. The down core quantitative distribution of prokaryotic and eukaryotic small subunit ribosomal RNA genes as well as functional genes involved in different biogeochemical processes was revealed by Q-PCR for the uppermost 10 m and for 80-140 m depth. Eukarya and the Fe(III- and Mn(IV-reducing bacterial group Geobacteriaceae were almost only found in the uppermost meter (arable soil, where reactive iron was detected in higher amounts. The bacterial candidate division JS-1 and the classes Anaerolineae and Caldilineae of the phylum Chloroflexi, highly abundant in marine sediments, were found up to the maximum sampling depth in high copy numbers at this terrestrial site as well. A similar high abundance of the functional gene cbbL encoding for the large subunit of RubisCO suggests that autotrophic microorganisms could be relevant in addition to heterotrophs. The functional gene aprA of sulfate reducing bacteria was found within distinct layers up to ca. 100 m depth

  7. Diets and trophic-guild structure of a diverse fish assemblage in Chesapeake Bay, U.S.A.

    Science.gov (United States)

    Buchheister, A; Latour, R J

    2015-03-01

    Dietary habits and trophic-guild structure were examined in a fish assemblage (47 species) of the Chesapeake Bay estuary, U.S.A., using 10 years of data from >25 000 fish stomachs. The assemblage was comprised of 10 statistically significant trophic guilds that were principally differentiated by the relative amounts of Mysida, Bivalvia, Polychaeta, Teleostei and other Crustacea in the diets. These guilds were broadly aggregated into five trophic categories: piscivores, zooplanktivores, benthivores, crustacivores and miscellaneous consumers. Food web structure was largely dictated by gradients in habitat (benthic to pelagic) and prey size. Size classes within piscivorous species were more likely to be classified into different guilds, reflecting stronger dietary changes through ontogeny relative to benthivores and other guilds. Relative to predator species and predator size, the month of sampling had negligible effects on dietary differences within the assemblage. A majority of sampled fishes derived most of their nutrition from non-pelagic prey sources, suggesting a strong coupling of fish production to benthic and demersal food resources. Mysida (predominantly the opossum shrimp Neomysis americana) contributed substantially to the diets of over 25% of the sampled predator groups, indicating that this species is a critical, but underappreciated, node in the Chesapeake Bay food web.

  8. Chesapeake Bay Program Water Quality Database

    Data.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    Lihwa Lin

    2015-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-09-15

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

  11. Origin and emplacement of impactites in the Chesapeake Bay impact structure, Virginia, USA

    Science.gov (United States)

    Horton, J.W.; Gohn, G.S.; Powars, D.S.; Edwards, L.E.

    2007-01-01

    The late Eocene Chesapeake Bay impact structure, located on the Atlantic margin of Virginia, may be Earth's best-preserved large impact structure formed in a shallow marine, siliciclastic, continental-shelf environment. It has the form of an inverted sombrero in which a central crater ???40 km in diameter is surrounded by a shallower brim, the annular trough, that extends the diameter to ???85 km. The annular trough is interpreted to have formed largely by the collapse and mobilization of weak sediments. Crystalline-clast suevite, found only in the central crater, contains clasts and blocks of shocked gneiss that likely were derived from the fragmentation of the central-uplift basement. The suevite and entrained megablocks are interpreted to have formed from impact-melt particles and crystalline-rock debris that never left the central crater, rather than as a fallback deposit. Impact-modified sediments in the annular trough include megablocks of Cretaceous nonmarine sediment disrupted by faults, fluidized sands, fractured clays, and mixed-sediment intercalations. These impact-modified sediments could have formed by a combination of processes, including ejection into and mixing of sediments in the water column, rarefaction-induced fragmentation and clastic injection, liquefaction and fluidization of sand in response to acoustic-wave vibrations, gravitational collapse, and inward lateral spreading. The Exmore beds, which blanket the entire crater and nearby areas, consist of a lower diamicton member overlain by an upper stratified member. They are interpreted as unstratified ocean-resurge deposits, having depositional cycles that may represent stages of inward resurge or outward anti-resurge flow, overlain by stratified fallout of suspended sediment from the water column. ?? 2008 The Geological Society of America. All rights reserved.

  12. Relation of lead exposure to sediment ingestion in mute swans on the Chesapeake Bay, USA

    Science.gov (United States)

    Beyer, W.N.; Day, D.; Morton, Alexandra; Pachepsky, Y.

    1998-01-01

    Forty-two mute swans (Cygnus olor ) were collected from unpolluted portions of central Chesapeake Bay in spring 1995. Their intestinal digesta were analyzed for 13 metals (Al, B, Ba, Cd, Cu, Fe, Mg, Mn, Ni, Pb, Sr, V, Zn) and for acid-insoluble ash, a marker of sediment. Because metal concentrations in digesta depend on recent exposure, they are appropriate for evaluating local contamination. Swan livers and sediment samples also were analyzed for the same metals. Group method of data handling demonstrated that the digesta Al was the best predictor of digesta Pb, and that adding concentrations of other metals as predictors did not improve the accuracy of the estimates of Pb concentrations from Al concentrations. The r2 of the equation relating the log of digesta Pb to the log of digesta Al was 0.86, whereas the r2 of the equation relating the log of digesta Pb to the log of digesta acid-insoluble ash was 0.50. Sediment ingestion was critical in determining exposure to Pb, as well as to some of the other metals, and should be considered in ecotoxicological risk assessments of waterfowl. The mean of 7.4% acid-insoluble ash in the digesta corresponded to an estimated 3.2% sediment in the diet. The Pb concentrations in the digesta were 2-3 times the concentration that would have been predicted from sediment Pb concentrations; presumably the swans had ingested clays high in Pb that had settled on the vegetation. The swans were not thought to have been exposed to high Cu concentrations but they had hepatic Cu concentrations that would be considered very high if found in other species.

  13. Mesoscale geomorphic change on low energy barrier islands in Chesapeake Bay, U.S.A.

    Science.gov (United States)

    Cooper, J. Andrew G.

    2013-10-01

    This paper presents an analysis of decadal (mesoscale) geomorphic change on sandy barrier islands in the fetch-limited environment of Chesapeake Bay. Low energy barrier islands exist in two settings: on the fringe of marshes and in open water and this analysis shows the various types of barrier island to be genetically related. Barrier islands that face the dominant wind and wave direction (E or W) retreat via barrier translation, preserving the barrier island volume. Those that exist in re-entrants are dominated by longshore transport processes, are strongly affected by sediment supply and are subject to disintegration. Marsh fringe barrier islands are perched on or draped over the surface of the underlying marsh. They migrate landwards via barrier translation during periodic high water events accompanied by large waves (hurricanes and northeasters). The underlying marsh surface erodes under all water levels and the rate of retreat of the barrier island and underlying marsh may take place at different rates, leading to various configurations from perched barrier islands several metres landward of the marsh edge, to barrier islands that have a sandy shoreface extending into the subtidal zone. The coastal configuration during landward retreat of marsh fringe barrier islands is subject to strong local control exerted by the underyling marsh topography. As erosion of marsh promontories occurs and marsh creeks are intersected and bypassed, the configuration is subject to rapid change. Periodic sediment influxes cause spits to develop at re-entrants in the marsh. The spits are initiated as extensions of adjacent marsh fringe barrier islands, but as the sediment volume is finite, the initial drift-aligned spits become sediment-starved and begin to develop a series of swash-aligned cells as they strive for morphodynamic equilibrium. The individual cells are stretched until breaches form in the barrier islands, creating inlets with tidal deltas. At this stage the low

  14. Chesapeake Bay: Introduction to an Ecosystem.

    Science.gov (United States)

    Environmental Protection Agency, Washington, DC.

    The Chesapeake Bay is the largest estuary in the contiguous United States. The Bay and its tidal tributaries make up the Chesapeake Bay ecosystem. This document, which focuses of various aspects of this ecosystem, is divided into four major parts. The first part traces the geologic history of the Bay, describes the overall physical structure of…

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

    Science.gov (United States)

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

    2016-08-01

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

  16. Chesapeake Bay Bald Eagle Nesting Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Chesapeake Bay population of breeding bald eagles increased dramatically in 1981 in not only the number of breeding pairs but in the number of nests hatching...

  17. Hydrogeomorphic Regions in the Chesapeake Bay Watershed.

    Data.gov (United States)

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

  18. Deriving Chesapeake Bay Water Quality Standards

    Science.gov (United States)

    Tango, Peter J.; Batiuk, Richard A.

    2013-01-01

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

  19. A shock-induced polymorph of anatase and rutile from the Chesapeake Bay impact structure, Virginia, U.S.A

    Science.gov (United States)

    Jackson, J.C.; Horton, J.W.; Chou, I.-Ming; Belkin, H.E.

    2006-01-01

    A shock-induced polymorph (TiO2II) of anatase and rutile has been identified in breccias from the late Eocene Chesapeake Bay impact structure. The breccia samples are from a recent, partially cored test hole in the central uplift at Cape Charles, Virginia. The drill cores from 744 to 823 m depth consist of suevitic crystalline-clast breccia and brecciated cataclastic gneiss in which the TiO2 phases anatase and rutile are common accessory minerals. Electron-microprobe imaging and laser Raman spectroscopy of TiO2 crystals, and powder X-ray diffraction (XRD) of mineral concentrates, confirm that a high-pressure, ??-PbO2 structured polymorph of TiO2 (TiO2II) coexists with anatase and rutile in matrix-hosted crystals and in inclusions within chlorite. Raman spectra of this polymorph include strong bands at wavenumbers (cm-1) 175, 281, 315, 342, 356, 425, 531, 571, and 604; they appear with anatase bands at 397, 515, and 634 cm-1, and rutile bands at 441 and 608 cm-1. XRD patterns reveal 12 lines from the polymorph that do not significantly interfere with those of anatase or rutile, and are consistent with the TiO2II that was first reported to occur naturally as a shock-induced phase in rutile from the Ries crater in Germany. The recognition here of a second natural shock-induced occurrence of TiO2II suggests that its presence in rocks that have not been subjected to ultrahigh-pressure regional metamorphism can be a diagnostic indicator for confirmation of suspected impact structures.

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

    Science.gov (United States)

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

    2009-01-01

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

  1. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Science.gov (United States)

    2010-07-01

    ... of Chesapeake Beach, Md.; firing range, Naval Research Laboratory. 334.170 Section 334.170 Navigation... RESTRICTED AREA REGULATIONS § 334.170 Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range... on the west by the shore of Chesapeake Bay. (2) Area B. The sector of a circle bounded by radii of...

  2. Endocrine disrupter - estradiol - in Chesapeake Bay tributaries

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-04-11

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

  3. Defining a data management strategy for USGS Chesapeake Bay studies

    Science.gov (United States)

    Ladino, Cassandra

    2013-01-01

    The mission of U.S. Geological Survey’s (USGS) Chesapeake Bay studies is to provide integrated science for improved understanding and management of the Chesapeake Bay ecosystem. Collective USGS efforts in the Chesapeake Bay watershed began in the 1980s, and by the mid-1990s the USGS adopted the watershed as one of its national place-based study areas. Great focus and effort by the USGS have been directed toward Chesapeake Bay studies for almost three decades. The USGS plays a key role in using “ecosystem-based adaptive management, which will provide science to improve the efficiency and accountability of Chesapeake Bay Program activities” (Phillips, 2011). Each year USGS Chesapeake Bay studies produce published research, monitoring data, and models addressing aspects of bay restoration such as, but not limited to, fish health, water quality, land-cover change, and habitat loss. The USGS is responsible for collaborating and sharing this information with other Federal agencies and partners as described under the President’s Executive Order 13508—Strategy for Protecting and Restoring the Chesapeake Bay Watershed signed by President Obama in 2009. Historically, the USGS Chesapeake Bay studies have relied on national USGS databases to store only major nationally available sources of data such as streamflow and water-quality data collected through local monitoring programs and projects, leaving a multitude of other important project data out of the data management process. This practice has led to inefficient methods of finding Chesapeake Bay studies data and underutilization of data resources. Data management by definition is “the business functions that develop and execute plans, policies, practices and projects that acquire, control, protect, deliver and enhance the value of data and information.” (Mosley, 2008a). In other words, data management is a way to preserve, integrate, and share data to address the needs of the Chesapeake Bay studies to better

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

    Science.gov (United States)

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

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Filipe Ribeiro

    2015-11-01

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

  6. Deep drilling in the Chesapeake Bay impact structure - An overview

    Science.gov (United States)

    Gohn, G.S.; Koeberl, C.; Miller, K.G.; Reimold, W.U.

    2009-01-01

    The late Eocene Chesapeake Bay impact structure lies buried at moderate depths below Chesapeake Bay and surrounding landmasses in southeastern Virginia, USA. Numerous characteristics made this impact structure an inviting target for scientific drilling, including the location of the impact on the Eocene continental shelf, its threelayer target structure, its large size (??85 km diameter), its status as the source of the North American tektite strewn field, its temporal association with other late Eocene terrestrial impacts, its documented effects on the regional groundwater system, and its previously unstudied effects on the deep microbial biosphere. The Chesapeake Bay Impact Structure Deep Drilling Project was designed to drill a deep, continuously cored test hole into the central part of the structure. A project workshop, funding proposals, and the acceptance of those proposals occurred during 2003-2005. Initial drilling funds were provided by the International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS). Supplementary funds were provided by the National Aeronautics and Space Administration (NASA) Science Mission Directorate, ICDP, and USGS. Field operations were conducted at Eyreville Farm, Northampton County, Virginia, by Drilling, Observation, and Sampling of the Earth's Continental Crust (DOSECC) and the project staff during September-December 2005, resulting in two continuously cored, deep holes. The USGS and Rutgers University cored a shallow hole to 140 m in April-May 2006 to complete the recovered section from land surface to 1766 m depth. The recovered section consists of 1322 m of crater materials and 444 m of overlying postimpact Eocene to Pleistocene sediments. The crater section consists of, from base to top: basement-derived blocks of crystalline rocks (215 m); a section of suevite, impact melt rock, lithic impact breccia, and cataclasites (154 m); a thin interval of quartz sand and lithic blocks (26 m); a

  7. Rock-avalanche and ocean-resurge deposits in the late Eocene Chesapeake Bay impact structure: Evidence from the ICDP-USGS Eyreville cores, Virginia, USA

    Science.gov (United States)

    Gohn, G.S.; Powars, D.S.; Dypvik, H.; Edwards, L.E.

    2009-01-01

    An unusually thick section of sedimentary breccias dominated by target-sediment clasts is a distinctive feature of the late Eocene Chesapeake Bay impact structure. A cored 1766-m-deep section recovered from the central part of this marine-target structure by the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) drilling project contains 678 m of these breccias and associated sediments and an intervening 275-m-thick granite slab. Two sedimentary breccia units consist almost entirely of Cretaceous nonmarine sediments derived from the lower part of the target sediment layer. These sediments are present as coherent clasts and as autoclastic matrix between the clasts. Primary (Cretaceous) sedimentary structures are well preserved in some clasts, and liquefaction and fluidization structures produced at the site of deposition occur in the clasts and matrix. These sedimentary breccias are interpreted as one or more rock avalanches from the upper part of the transient-cavity wall. The little-deformed, unshocked granite slab probably was transported as part of an extremely large slide or avalanche. Water-saturated Cretaceous quartz sand below the slab was transported into the seafloor crater prior to, or concurrently with, the granite slab. Two sedimentary breccia units consist of polymict diamictons that contain cobbles, boulders, and blocks of Cretaceous nonmarine target sediments and less common shocked-rock and melt ejecta in an unsorted, unstratified, muddy, fossiliferous, glauconitic quartz matrix. Much of the matrix material was derived from Upper Cretaceous and Paleogene marine target sediments. These units are interpreted as the deposits of debris flows initiated by the resurge of ocean water into the seafloor crater. Interlayering of avalanche and debris-flow units indicates a partial temporal overlap of the earlier avalanche and later resurge processes. A thin unit of stratified turbidite deposits and overlying laminated

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

    Directory of Open Access Journals (Sweden)

    Kristi S Shaw

    2014-05-01

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

  9. Chesapeake Bay Bald Eagle Breeding Survey 1978

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In its second year, the Chesapeake Region Eagle Group (CREG) obtained the data for this report. CREG consists of representatives of the U.S. Fish and Wildlife...

  10. Chesapeake Bay Future Conditions Report. Volume 6. Water Quality

    Science.gov (United States)

    1977-12-01

    and paper industries for example, lingosulfates or pulp wastes can be synthesized to produce artificial vanilla flavoring and other valuable acetic...Plants in the Chesapeake Bay Area. Ozone is a blue, pungent smelling, unstable gas existing as an oxidized form of oxygen. Disinfec- tion by ozonation is

  11. Numerical Modeling of Storm Surges in Chesapeake Bay

    Science.gov (United States)

    2008-01-01

    bathymetry grid was developed from several data sources, including the National Ocean Service (NOS) Digital Navigation Charts ( DNC ), bathymetry data from...of Virginia and Maryland coasts. This grid was refined in Chesapeake Bay (Figure 5) using the NOS/ DNC data, a composite dataset from VIMS, GEODAS

  12. Chesapeake Bay Low Freshwater Inflow Study. Appendix E. Biota.

    Science.gov (United States)

    1984-09-01

    Freshwater Inflow Study, results of testing on the Chesapeake b~ay Hydraulic - Model were used to assess the effects on the Bay of projected future depressed ...the orginal list. One species which elicited wide-spread comment was the American shad, Alosa sapidissima. In light of its severely depressed ...organisms that spend only a part of their life cycle as a member of the plankton. microbiota : the microscopic organisms present in an area. . mollusk

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

    Science.gov (United States)

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

  14. Chesapeake Bay Low Freshwater Inflow Study.

    Science.gov (United States)

    1984-09-01

    and When Captain John Smith first ex- migrations of at least 10 percent. In the between one community and another. plored the Chesapeake in 1608, it...will be adopted by Boating. Rises in maintenance costs Through its many support facilities and the water supply authorities.boationg es and mainan ope... Smith , William Stolting, Norton, Jr., Chris Ostrom, Donald H . NMcAuley, James E. McShane, .Jane Stindberg, Nelson Swink, Dav id Outen, Kenneth E

  15. Chesapeake Bay impact structure: A blast from the past

    Science.gov (United States)

    Powars, David S.; Edwards, Lucy E.; Gohn, Gregory S.; Horton, Jr., J. Wright

    2015-10-28

    About 35 million years ago, a 2-mile-wide meteorite smashed into Earth in what is now the lower Chesapeake Bay in Virginia. The oceanic impact vaporized, melted, fractured, and displaced rocks and sediments and sent billions of tons of water, sediments, and rocks into the air. Glassy particles of solidified melt rock rained down as far away as Texas and the Caribbean. Large tsunamis affected most of the North Atlantic basin. The resulting impact structure is more than 53 miles wide and has a 23-mile-wide, filled central crater surrounded by collapsed sediments. Now buried by hundreds of feet of younger sediments, the Chesapeake Bay impact structure is among the 20 largest known impact structures on Earth.

  16. Tidal Marshes across a Chesapeake Bay Subestuary Are Not Keeping up with Sea-Level Rise

    OpenAIRE

    Beckett, Leah H.; Baldwin, Andrew H.; Kearney, Michael S

    2016-01-01

    Sea-level rise is a major factor in wetland loss worldwide, and in much of Chesapeake Bay (USA) the rate of sea-level rise is higher than the current global rate of 3.2 mm yr-1 due to regional subsidence. Marshes along estuarine salinity gradients differ in vegetation composition, productivity, decomposition pathways, and sediment dynamics, and may exhibit different responses to sea-level rise. Coastal marshes persist by building vertically at rates at or exceeding regional sea-level rise. In...

  17. Field guide to fishes of the chesapeake bay

    CERN Document Server

    Murdy, Edward O.

    2013-01-01

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

  18. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Science.gov (United States)

    2010-07-01

    ... to Chesapeake Bay; firing range. 334.390 Section 334.390 Navigation and Navigable Waters CORPS OF....390 Atlantic Ocean south of entrance to Chesapeake Bay; firing range. (a) The danger zone. A section... four (4) nautical miles. (3) Firing on the ranges will be suspended as long as any vessel is within...

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

    Institute of Scientific and Technical Information of China (English)

    YU Qingyun; WANG You; TANG Xuexi; LI Ming

    2013-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  1. Verification of the Chesapeake Bay Model.

    Science.gov (United States)

    1981-12-01

    line of the five cups was about 0.045 ft above the bottom of the meter frame; 30 STEPPING MOTOR 200 STEPS REVOLUTION TRANSLATOR SRPPOT.E SELECTOR DIST...about 0.1 ft in the model, represented a horizontal width of about 100 ft in the prototype. The height of the meter cups , about 0.04 ft, represented...the entire bay. Although station-to-station wind magnitude comparisons cannot be made due to variations in anemometer height and exposure, wind-field

  2. Diet selectivity of juvenile blue crabs (Callinectes sapidus) in Chesapeake Bay.

    Science.gov (United States)

    Seitz, Rochelle D; Knick, Kathleen E; Westphal, Miranda

    2011-10-01

    Shallow coves in Chesapeake Bay have abundant food and serve as nursery grounds for juvenile blue crabs. In this study, we examined the relationships between the diet of very small (4-40 mm CW) juvenile blue crabs and the benthic infauna in shallow, unvegetated nursery coves. We compared infauna in benthic samples with gut contents of juvenile blue crabs from six shallow coves in each of two sub-estuaries (Rappahannock and York Rivers) in Chesapeake Bay, Virginia, USA. Benthic communities differed depending on river and location, with abundant clams in upriver regions and abundant polychaetes in downriver regions. Juvenile crabs, like adults, appeared to be opportunistic feeders, with gut contents including clams, amphipods, polychaetes, small crustaceans, plant matter, and detritus. There was a positive relationship between polychaetes in the benthic samples and in crab guts, suggesting that juvenile crabs are opportunistic feeders on polychaetes in the benthos. Moreover, Ivlev's electivity index and foraging ratio showed that clams and polychaetes were selectively eaten at all locations. Alternatively, crabs selectively rejected amphipods. Crab densities corresponded positively with polychaete densities, which suggests that there may be bottom-up control of crab distributions and that food resources are important in nursery habitats.

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

    Data.gov (United States)

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

  4. Monitoring wetland inundation dynamics in response to weather variability in the Chesapeake Bay watershed

    Science.gov (United States)

    Wetlands provide a broad range of ecosystem services, including flood control, water purification, groundwater replenishment, and biodiversity support. The provision of these services, which are especially valued in the Chesapeake Bay Watershed, is largely controlled by varying levels of wetness. ...

  5. Changes in Stream Water Temperatures in the Chesapeake Bay Region, 1960-2014

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the changes in stream water temperatures in the Chesapeake Bay region from 1960 to 2014. Blue circles represent cooling trends in stream water...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    KAUST Repository

    Gilerson, Alexander

    2015-10-14

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

  9. Chesapeake Bay Impact Structure Deep Drilling Project Completes Coring

    Directory of Open Access Journals (Sweden)

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

    2006-09-01

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

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

    Science.gov (United States)

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

    2013-11-14

    High-salinity groundwater more than 1,000 metres deep in the Atlantic coastal plain of the USA has been documented in several locations, most recently within the 35-million-year-old Chesapeake Bay impact crater. Suggestions for the origin of increased salinity in the crater have included evaporite dissolution, osmosis and evaporation from heating associated with the bolide impact. Here we present chemical, isotopic and physical evidence that together indicate that groundwater in the Chesapeake crater is remnant Early Cretaceous North Atlantic (ECNA) sea water. We find that the sea water is probably 100-145 million years old and that it has an average salinity of about 70 per mil, which is twice that of modern sea water and consistent with the nearly closed ECNA basin. Previous evidence for temperature and salinity levels of ancient oceans have been estimated indirectly from geochemical, isotopic and palaeontological analyses of solid materials in deep sediment cores. In contrast, our study identifies ancient sea water in situ and provides a direct estimate of its age and salinity. Moreover, we suggest that it is likely that remnants of ECNA sea water persist in deep sediments at many locations along the Atlantic margin.

  11. Conceptual Design of a Chesapeake Bay Environmental Observatory (CBEO)

    Science.gov (United States)

    Ball, W. P.; di Toro, D.; Gross, T. F.; Kemp, W. M.; Burns, R.; Piasecki, M.; Zaslavsky, I.; Cuker, B. E.; Murray, L.

    2006-12-01

    A new project is underway to develop and deploy a Chesapeake Bay Environmental Observatory (CBEO), which is intended to serve as a prototype of cyberinfrastructure (CI) for environmental observatory networks (EONs) that will demonstrate the transformative power of CI. The CBEO will be developed by a team of highly qualified computer scientists, ecologists, oceanographers and environmental engineers with a track record of working together on environmental observatory projects and complex cross-discipline research efforts. The project approach has been organized around the following four concurrent interacting elements, which follow the acronym "NETS": (1) The CBEO:N group will incorporate the test bed CI into the national EONs by constructing a GEON-based node for the CBEO. This will entail resolving complex cross-disciplinary issues of semantics, syntax and inter- operability as well as developing new shared CI tools for data assimilation and interpolation. (2) CBEO:E is the education element and will use the CBEO to translate observational science for public consumption. Direct participation of multicultural students and a K-12 teacher are planned. The test-bed and network components (described below and above) will provide the focus of five workshops for users, managers and science educators; (3) Prior to full integration via CBEO:N, CBEO:T will rapidly construct a locally accessible CBEO test-bed prototype that will integrate a subset of currently available large data sets characterized by multiple variables and widely disparate time and space scales ? grab and continuous sampling at fixed stations, undulating towed sensors, and satellite and aircraft remote sensing. A novel feature will be the inclusion of the fifteen year (1986-2000) simulated data from the Bay-wide fine spatial (1-10 km) and temporal (0.02-1 hr) scale hydrodynamic and water quality model. CBEO:T will serve initially as the development platform for data integration, interpolation, and

  12. Watershed nutrient inputs, phytoplankton accumulation, and C stocks in Chesapeake Bay

    Science.gov (United States)

    Fisher, T. R.; Boynton, W. R.; Hagy, J. D.

    2002-12-01

    Inputs of N and P to Chesapeake Bay have been enhanced by anthropogenic activities. Fertilizers, urbanization, N emissions, and industrial effluents contribute to point and diffuse sources currently 2-7X higher for P and 5-20X higher for N than those from undisturbed watersheds. Enhanced nutrient inputs cause phytoplankton blooms which obscure visibility, eliminate submerged grasses, and influence the distribution of C within the Bay. Accumulations of dissolved organic and particulate organic C lead to enhanced microbial respiration in isolated bottom waters, and dissolved oxygen is seasonally reduced to trace levels during summer. Cultural eutrophication is not unique to Chesapeake Bay. Although some estuaries such as the Delaware, Hudson, and San Francisco Bay also have high anthropogenic inputs, these estuaries have much shorter residence times, and much of the N and P may be exported to the coastal ocean. However, in Chesapeake Bay, with residence times >2 months, internal processing of watershed inputs results in local algal blooms within the estuary. Watershed restoration strategies for Chesapeake watersheds have had limited success to date. Groundwaters are enriched with nitrate, and the long residence times of groundwaters mean slow responses to watershed improvements. The few successes in the Chesapeake have been associated with point source reductions, although continued human population growth can easily override restoration efforts. Widespread improvement in water quality has yet to occur, but the limited successes show that the Bay responds to load changes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-19

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

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

    Science.gov (United States)

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

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

  15. Metal concentrations in oldsquaw (Clangula hyemalis) during an outbreak of avian cholera, Chesapeake Bay, 1994

    Science.gov (United States)

    Mashima, T.Y.; Fleming, W.J.; Stoskopf, M.K.

    1998-01-01

    Forty out of 41 oldsquaw carcasses collected during a 3 month avian cholera outbreak in Chesapeake Bay, USA, in 1994 were culture positive for Pasteurella multocida. Pasteurella-positive birds collected in February had greater (p ??? 0.05) mean (geometric) liver concentrations of cadmium (7.35 versus 3.71 ??g per g dry weight) and lower concentrations of selenium (9.90 versus 12.5 ??g per g dry weight) than Pasteurella-positive birds collected during March and April. The mercury content of the livers and cadmium content of the kidneys did not differ (p > 0.05) between birds collected early in the die-off and those collected in March and April. The liver and kidney concentrations of metals in the Pasteurella-positive birds collected in 1994 were compared to apparently healthy oldsquaw (n = 67) collected from Chesapeake Bay during 1985-1987, because healthy oldsquaw were not collected during the avian cholera outbreak in 1994. Compared to the apparently healthy oldsquaw collected in 1985-1987, the mean concentrations of cadmium (liver 4.32 versus 2.65 ??g per g dry weight and kidney 22.7 versus 11.5 ??g per g dry weight) were greater (p ??? 0.05) in the oldsquaw which succumbed to avian cholera in 1994. In contrast, the liver concentrations of selenium (11.9 versus 17.8 ??g per g dry weight) and mercury (0.389 versus 1.83 ??g per g dry weight) were lower (p ??? 0.05) in the birds from the 1994 die-off than for the apparently healthy oldsquaw collected in 1985-1987. Three birds from the 1985-1987 cohort and none of the birds from the 1994 cohort had liver lead concentrations greater than 4 ??g per g dry weight. The results of this study indicate a possible link between high cadmium tissue concentrations and susceptibility to avian cholera in oldsquaw.

  16. Modeling Land Use Change in the Chesapeake Bay Watershed

    Science.gov (United States)

    Claire, J. A.; Goetz, S. J.; Bockstael, N.

    2003-12-01

    Low density, decentralized residential and commercial development is increasingly the dominant pattern of exurban land use in many developed countries, particularly the United States. The term "sprawl" is now commonly used to describe this form of development, the environmental and quality-of-life impacts of which are becoming central to debates over land use in urban and suburban areas. Continued poor health of the Chesapeake Bay, located in the Mid-Atlantic region of the United States, is due in part to disruptions in the hydrological system caused by urban and suburban development throughout the 167,000 square kilometer watershed. We present results of a spatial predictive model of land use change based on cellular automata (SLEUTH), which was calibrated using high resolution (30m cell size) maps of the built environment derived from Landsat ETM+ imagery for the period 1986-2000. The model was applied to a 23,740 square kilometer area centered on Washington DC - Baltimore MD, and predictions were made out to 2030 assuming three different policy scenarios (current trends, managed growth, and "sustainable"). Accuracy of the model was assessed at three scales (pixel, watershed and county) and overall strengths and weaknesses of the model are presented, particularly in comparison to other econometric modeling approaches.

  17. Black ducks and their Chesapeake Bay habitats : proceedings of a symposium

    Science.gov (United States)

    Perry, Matthew C.

    2002-01-01

    The symposium 'Black Ducks and Their Chesapeake Bay Habitats,' held October 4, 2000, provided a forum for scientists to share research about the American black duck (Anas rubripes), an important breeding and wintering waterfowl species dependent upon the Chesapeake Bay habitats. American black ducks have declined significantly in the last 50 years and continue to be a species of management concern. The symposium, sponsored by the Wildfowl Trust of North America and the U.S. Geological Survey, highlighted papers and posters on a range of topics, from the traditional concerns of hunting, habitat, and hybridization to the more recent concerns of human disturbance and neophobia. Other presentations provided a historical perspective of black duck management. The direction that black duck conservation initiatives could and/or should take in the future was also discussed. As populations of humans in the Chesapeake Bay region continue to increase, we can expect that these subjects will receive increased discussion in the future.

  18. U.S. Geological Survey Chesapeake Bay Studies: Scientific Solutions for a Healthy Bay and Watershed

    Science.gov (United States)

    Phillips, Scott

    2006-01-01

    The U.S. Geological Survey (USGS), the science agency for the Department of Interior (DOI), has the critical role of providing objective science to document and understand ecosystem change in the Chesapeake Bay and its watershed. The human population in the Bay watershed, which grew from 8.1 million in 1950 to almost 16 million in 2000, has resulted in degraded water quality, loss of habitat, and declines in fish and bird populations. USGS scientists are leaders in understanding cause and effect of human activities and natural changes on water quality and the health of the ecosystem. The USGS interacts with resource managers and policy makers to use the science to adapt approaches for implementation, and assess effectiveness of, management actions for ecosystem conservation, restoration, and sustainability.

  19. A summary report of sediment processes in Chesapeake Bay and watershed

    Science.gov (United States)

    Langland, Michael; Cronin, Thomas

    2003-01-01

    The Chesapeake Bay, the Nation's largest estuary, has been degraded because of diminished water quality, loss of habitat, and over-harvesting of living resources. Consequently, the bay was listed as an impaired water body due to excess nutrients and sediment. The Chesapeake Bay Program (CBP), a multi-jurisdictional partnership, completed an agreement called ?Chesapeake 2000? that revises and establishes new restoration goals through 2010 in the bay and its watershed. The goal of this commitment is the removal of the bay from the list of impaired waterbodies by the year 2010. The CBP is committed to developing sediment and nutrient allocations for major basins within the bay watershed and to the process of examining new and innovative management plans in the estuary itself and along the coastal zones of the bay. However, additional information is required on the sources, transport, and deposition of sediment that affect water clarity. Because the information and data on sediment processes in the bay were not readily accessible to the CBP or to state, and local managers, a Sediment Workgroup (SWGP) was created in 2001. The primary objective of this report, therefore, is to provide a review of the literature on the sources, transport, and delivery of sediment in Chesapeake Bay and its watershed with discussion of potential implications for various management alternatives. The authors of the report have extracted, discussed, and summarized the important aspects of sediment and sedimentation that are most relevant to the CBP and other sediment related-issues with which resources managers are involved. This report summarizes the most relevant studies concerning sediment sources, transport and deposition in the watershed and estuary, sediments and relation to water clarity, and provides an extensive list of references for those wanting more information.

  20. 1972 American Eagle Nest Survey of the Chesapeake Bay Region.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data refers to the 1972 nesting season for the Bald Eagle in the Chesapeake area to include Virginia and Maryland. The 1972 nesting season for the Bald Eagle in the...

  1. 1982 Bald Eagle Nest Survey, Chesapeake Bay Region.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data refers to the 1982 nesting season for the Bald Eagle in the Chesapeake area to include Virginia, Maryland and Delaware. For the third year in succession we have...

  2. 1970 American Eagle Nest Survey of the Chesapeake Bay Region.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Data refers to the 1970 nesting season for the Bald Eagle in the Chesapeake area to include Virginia and Maryland. The 1970 results are most disappointing since...

  3. 75 FR 53298 - A Method to Assess Climate-Relevant Decisions: Application in the Chesapeake Bay

    Science.gov (United States)

    2010-08-31

    ... AGENCY A Method to Assess Climate-Relevant Decisions: Application in the Chesapeake Bay AGENCY... 60-day public comment period for the draft document titled, ``A Method to Assess Climate-Relevant... and must be received by EPA by November 1, 2010. ADDRESSES: The draft ``A Method To Assess...

  4. 33 CFR 334.220 - Chesapeake Bay, south of Tangier Island, Va.; naval firing range.

    Science.gov (United States)

    2010-07-01

    ... Island, Va.; naval firing range. 334.220 Section 334.220 Navigation and Navigable Waters CORPS OF....220 Chesapeake Bay, south of Tangier Island, Va.; naval firing range. (a) The danger zone. Beginning... the range will be conducted intermittently by one or more vessels, depending on weather and...

  5. 75 FR 34367 - Safety Zone; Shore Thing & Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Science.gov (United States)

    2010-06-17

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Shore Thing & Independence Day Fireworks... is establishing a temporary safety zone on the Chesapeake Bay in the vicinity of Ocean View Beach Park, Norfolk, VA in support of the Shore Thing & Independence Day Fireworks event. This action...

  6. 76 FR 38300 - Safety Zone; Shore Thing and Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Science.gov (United States)

    2011-06-30

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Shore Thing and Independence Day Fireworks... is establishing a temporary safety zone on the Chesapeake Bay in the vicinity of Ocean View Beach Park, Norfolk, VA in support of the Shore Thing and Independence Day Fireworks event. This action...

  7. EPA Interim Evaluation of 2012-2013 Milestone Progress in the Chesapeake Bay Watershed

    Science.gov (United States)

    This page provides the EPA interim evaluations of the 2012-2013 milestones for the Chesapeake Bay TMDL. These interim assessments provide a mid-point check on the progress made on the 2012-2013 milestones, recognizing the achievements made in 2012.

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

    Science.gov (United States)

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

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

  9. SETTLEMENT AND SURVIVAL OF THE OYSTER CRASSOSTREA VIRGINICA ON CREATED OYSTER REEF HABITATS IN CHESAPEAKE BAY

    Science.gov (United States)

    Efforts to restore the Eastern oyster (Crassostrea virginica) reef habitats in Chesapeake Bay typically begin with the placement of hard substrata to form three-dimensional mounds on the seabed to serve as a base for oyster recruitment and growth. A shortage of oyster shell for ...

  10. 33 CFR 334.350 - Chesapeake Bay off Fort Monroe, Va.; firing range danger zone.

    Science.gov (United States)

    2010-07-01

    ..., Va.; firing range danger zone. 334.350 Section 334.350 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.350 Chesapeake Bay off Fort Monroe, Va.; firing range danger zone. (a) The danger zone. All of...

  11. 33 CFR 334.140 - Chesapeake Bay; U.S. Army Proving Ground Reservation, Aberdeen, Md.

    Science.gov (United States)

    2010-07-01

    ....140 Chesapeake Bay; U.S. Army Proving Ground Reservation, Aberdeen, Md. (a) Restricted area defined. The following indicates the limits of the waters of or adjacent to the Aberdeen Proving Ground, Maryland, and inside of which boundaries will lie the restricted area known as the Aberdeen Proving...

  12. Chesapeake Bay Low Freshwater Inflow Study. Biota Assessment. Phase I. Appendices.

    Science.gov (United States)

    1980-08-01

    in lower Bay. 11. Macrofauna distribution with respect to sediment size. 12. Benthic infauna and sediment chemistry survey. 13. Plankton response to...transparent, gelatinous animal, roughly pear-shaped, with four oral lobes. Adults have no tentacles. The organism swims by means of its 8 rows of comb... planktonic rotifer of the family Brachionidae. Range: Brachionis calyciflorus is found worldwide in temperate fresh and oligohaline areas. In Chesapeake Bay

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

    Science.gov (United States)

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

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  19. A Model for the Formation of the Chesapeake Bay Impact Crater as Revealed by Drilling and Numerical Simulation

    Science.gov (United States)

    Collins, G. S.; Kenkmann, T.; Wünnemann, K.; Wittmann, A.; Reimold, W. U.; Melosh, H. J.

    The combination of numerical simulation results and petrographic analysis of drill core from the recent ICDP-USGS drilling project provides new insight into the formation of the Chesapeake Bay impact crater.

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    D. L. Griscom

    2012-02-01

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

  4. Multi-decadal variation in size of juvenile Summer Flounder (Paralichthys dentatus) in Chesapeake Bay

    Science.gov (United States)

    Nys, Lauren N.; Fabrizio, Mary C.; Tuckey, Troy D.

    2016-01-01

    During the last quarter-century, management of Summer Flounder Paralichthys dentatus along the Atlantic coast resulted in significant increases in abundance such that rebuilding targets were recently achieved. Although spawning stock biomass is high, recruitment of young-of-the-year (YOY) Summer Flounder remains variable. Chesapeake Bay is one of the principal nursery areas for this species, but processes such as growth and survival that affect production of YOY Summer Flounder in this estuary have not been explored. Here, we investigated the relationship between abundance and size of Summer Flounder recruits from the 1988 to 2012 year classes in Chesapeake Bay. We also considered the effects of environmental factors on fish size because conditions in the bay vary spatially during the time that fish occupy nursery areas. To describe variations in Summer Flounder size, we used monthly length observations from 13,018 YOY fish captured by bottom trawl from the lower Chesapeake Bay and the James, York, and Rappahannock river subestuaries where Summer Flounder are commonly observed. We applied a generalized additive model to describe spatial, temporal, and environmental effects on observed fish size; we also considered the density of Summer Flounder and an index of productivity as factors in the model. Summer Flounder in Chesapeake Bay exhibited density-dependent and spatially related variations in mean length: larger fish were found mostly in the Bay and smaller fish in the subestuaries. Additionally, low ( 26 °C) temperatures and low salinities (fish size, indicating that individuals found in these environments were typically smaller than conspecifics inhabiting areas of moderate temperatures and higher salinities. Variable nursery habitat conditions in temperate estuaries affect fish size and, subsequently, may influence production of Summer Flounder year classes through effects on maturation and survival. As water temperatures in the mid-Atlantic region continue to

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

    Science.gov (United States)

    Moore, Rachel

    2011-01-01

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

  6. Influence of Conowingo Reservoir Infill on Chesapeake Bay Deep Water Hypoxia

    Science.gov (United States)

    Linker, L. C.; Cerco, C. F.; Batiuk, R.

    2014-12-01

    The Chesapeake Bay Total Maximum Daily Load (TMDL) requires the reduction of nitrogen, phosphorus, and sediment loads in the Chesapeake watershed because of the tidal water quality impairments and the damage to living resources they cause. Within the Chesapeake watershed the Conowingo Reservoir has been filling in with sediment for almost a century, and is now in a state of near-full capacity called dynamic equilibrium. The development of the Chesapeake TMDL in 2010 was with the hydrology of a 1991-2000 simulation period, and carried with this simulation period the implicit model calibration assumption, based on the 1991-2000 nutrient and sediment observations, of a Conowingo Reservoir that was still effectively trapping sediment. In a TMDL, pollutant loads beyond the TMDL allocation, which are brought about by growth or other conditions, must be offset. Using the analysis tools of the Chesapeake TMDL for assessing the degree of attainment of living resource based water quality standards, the estimated nutrient and sediment loads from a simulated infill of the Conowingo Reservoir was determined. The influence on Chesapeake water quality by a large storm and scour event of January 1996 on the Susquehanna was estimated and the same storm and scour events were also evaluated in the more critical living resource periods of June and October. An analysis was also made on the estimated influence of more moderate but frequent high flow events. The infill of the Conowingo reservoir had estimated impairments of water quality at both the simulated high flow scour events and at the more frequent moderate storm flows. The estimated impairment was primarily on the deep water and deep channel dissolved oxygen because of increased scour and transport of dissolved particulate organic nutrients under conditions of Conowingo infill. Figure 1 describes the linked models used to assess the impact of Conowingo Reservoir infill on Chesapeake hypoxia.

  7. Late Pleistocene eolian features in southeastern Maryland and Chesapeake Bay region indicate strong WNW-NW winds accompanied growth of the Laurentide Ice Sheet

    Science.gov (United States)

    Markewich, H.W.; Litwin, R.J.; Pavich, M.J.; Brook, G.A.

    2009-01-01

    Inactive parabolic dunes are present in southeastern Maryland, USA, along the east bank of the Potomac River. More elongate and finer-grained eolian deposits and paha-like ridges characterize the Potomac River-Patuxent River upland and the west side of Chesapeake Bay. These ridges are streamlined erosional features, veneered with eolian sediment and interspersed with dunes in the low-relief headwaters of Potomac- and Patuxent-river tributaries. Axis data for the dunes and ridges indicate formation by WNW-NW winds. Optically stimulated luminescence and radiocarbon age data suggest dune formation from ??? 33-15??ka, agreeing with the 30-13??ka ages Denny, C.S., Owens, J.P., Sirkin, L., Rubin, M., 1979. The Parsonburg Sand in the central Delmarva Peninsula, Maryland and Delaware. U.S. Geol. Surv. Prof. Pap. 1067-B, 16??pp. suggested for eolian deposits east of Chesapeake Bay. Age range and paleowind direction(s) for eolian features in the Bay region approximate those for late Wisconsin loess in the North American midcontinent. Formation of midcontinent loess and Bay-region eolian features was coeval with rapid growth of the Laurentide Ice Sheet and strong cooling episodes (??18O minima) evident in Greenland ice cores. Age and paleowind-direction coincidence, for eolian features in the midcontinent and Bay region, indicates strong mid-latitude WNW-NW winds for several hundred kilometers south of the Laurentide glacial terminus that were oblique to previously simulated anticyclonic winds for the last glacial maximum.

  8. Remote sensing of submerged aquatic vegetation in the lower Chesapeake Bay. [(sea grasses)

    Science.gov (United States)

    Orth, R. J.; Gordon, H. R.

    1975-01-01

    An experimental water penetration film and black and white near infrared film were used to study the distribution of submerged aquatic vegetation in the lower Chesapeake Bay. Detailed description of the grass beds was obtained by flying at an altitude of 5,000 feet, at low tide when wind conditions were minimal. Results show that there was a 36% reduction in the amount of submerged aquatic vegetation in the lower Chesapeake Bay from 1971 to 1974, the greatest losses occurring in the York, Piankatank and Rappahannock rivers (tabulated data is given). Recovery of some grass beds occurs primarily through seedling recruitment and subsequent vegetative growth. Cownose rays are suspected as a main factor for the decimation of some of the grass beds. Maps and photographs of the areas studied are given.

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

    Science.gov (United States)

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

    2016-03-01

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

  10. Modeling hypoxia in the Chesapeake Bay: Ensemble estimation using a Bayesian hierarchical model

    Science.gov (United States)

    Stow, Craig A.; Scavia, Donald

    2009-02-01

    Quantifying parameter and prediction uncertainty in a rigorous framework can be an important component of model skill assessment. Generally, models with lower uncertainty will be more useful for prediction and inference than models with higher uncertainty. Ensemble estimation, an idea with deep roots in the Bayesian literature, can be useful to reduce model uncertainty. It is based on the idea that simultaneously estimating common or similar parameters among models can result in more precise estimates. We demonstrate this approach using the Streeter-Phelps dissolved oxygen sag model fit to 29 years of data from Chesapeake Bay. Chesapeake Bay has a long history of bottom water hypoxia and several models are being used to assist management decision-making in this system. The Bayesian framework is particularly useful in a decision context because it can combine both expert-judgment and rigorous parameter estimation to yield model forecasts and a probabilistic estimate of the forecast uncertainty.

  11. Chesapeake Bay recovery and factors affecting trends: Long-termmonitoring, indicators, and insights

    Science.gov (United States)

    Tango, Peter J.; Batiuk, Richard A.

    2016-01-01

    Monitoring the outcome of restoration efforts is the only way to identify the status of a recovery and the most effective management strategies. In this paper, we discuss Chesapeake Bay and watershed recovery and factors influencing water quality trends. For over 30 years, the Chesapeake Bay Program Partnership’s long-term tidal and watershed water quality monitoring networks have measured physical, chemical and biological parameters throughout the bay and its surrounding watershed underpinning an adaptive management process to drive ecosystem recovery. There are many natural and anthropogenic factors operating and interacting to affect the watershed and bay water quality recovery responses to management actions. Across habitats and indicators, the bay and its watershed continue to express a diverse spatial and temporal fabric of multiscale conditions, stressors and trends that show a range of health conditions and impairments, as well as evidence of progress and degradation. Recurrent independent reviews of the monitoring program have driven a culture of continued adaptation of the monitoring networks to reflect ever evolving management information needs. The adherence to bay and watershed-wide consistent monitoring protocols provides monitoring data supporting analyses and development of scientific syntheses that underpin indicator and model development, regulatory assessments, targeting of management actions, evaluation of management effectiveness, and directing of priorities and policies.

  12. Using Seeds to Propagate and Restore Vallisneria americana Michaux (Wild Celery) in the Chesapeake Bay

    Science.gov (United States)

    2007-12-01

    Granger et al. 2002). Only more recently have techniques been developed to use seeds in the restoration of some brackish and freshwater SAV species...Chesapeake Bay, including aspects of the collection, storage, germination , and seedling growth. The goal is to improve restoration success of this...the depression created by the pistillate flower and pollen is deposited onto the stigma (Sculthorpe 1967; Kaul 1978). a complete review). The species

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    - tuarine waters have been based on visual detection of lu- minescence and have, therefore, omitted non-visibly luminous strains (dark variants). Marine luminous bacte- rial numbers enumerated in this manner range from non- 0168-6496 / 00 / $20.00 2000..., heterotrophic bacteria from Chesapeake Bay water samples (results not shown). 2.5. Detection of light emission Emission of light by laboratory strains and bacterial colonies isolated from environmental samples was checked visually in a photographic dark room...

  14. Large-Scale Submerged Aquatic Vegetation Restoration in Chesapeake Bay: Status Report, 2003-2006

    Science.gov (United States)

    2008-06-01

    marina), (2) wild celery (V. americana), (3) sago pondweed (S. pectinata), and (4) redhead grass (P. perfoliatus). Molecular and cultivation...depth and density on germination and development of Zostera marina L. seeds. Biologia Marina Mediterranea 7(3):55–58. Granger, S., M. Traber, S. W...sago pondweed (S. pectinata), and redhead grass (P. perfoliatus) collected from different regions of the Chesapeake Bay. Molecular and cultivation

  15. Evaluation of groundwater resources of the Chesapeake Bay Watershed using an integrated hydrologic model

    Science.gov (United States)

    Seck, A.; Welty, C.; Maxwell, R. M.

    2013-12-01

    We present results from a distributed integrated hydrologic model of the Chesapeake Bay Watershed using ParFlow-CLM. The model covers an area of 400,000 km2 spanning five physiographic provinces, discretized at a horizontal resolution of 2 km and vertical resolution of 5 m. Synthesis of published hydrogeologic data as well as analysis of well completion reports from state agencies were used to construct a hydrogeologic model framework. The model was run for the period of 2003-2004 using National Land Data Assimilation System (NLDAS) meteorological forcing. Model output captures seasonal and spatial variability in subsurface storage and surface storage, and produces water table depths consistent with the topography, meteorological forcing, and hydrogeological setting. Model results show spatial variability in evaporation fluxes correlated to land cover at higher resolution than either NLDAS outputs or the EPA Chesapeake Bay Watershed Model Phase 5.3. Comparison with USGS streamflow data at selected stream gages shows good agreement in daily discharge timing and fluxes for high and average flows, whereas the model does not perform as well for low flows during summer and dry periods. Analysis of groundwater stores and fluxes showed marked variability across physiographic provinces. Highest groundwater stores were expectedly found in the Coastal Plain, while the Blue Ridge physiographic province had the lowest stores. The Appalachian Plateau was characterized by the highest net recharge rates. The highest discharge rates were found in the Valley and Ridge, Piedmont and Coastal Plain. The construction of this model constitutes a step forward in understanding the groundwater system in the Chesapeake Bay Watershed and its role in solute delivery to the Chesapeake Bay.

  16. Long-term reductions in anthropogenic nutrients link to improvements in Chesapeake Bay habitat

    Science.gov (United States)

    Ruhl, H.A.; Rybicki, N.B.

    2010-01-01

    Great effort continues to focus on ecosystem restoration and reduction of nutrient inputs thought to be responsible, in part, for declines in estuary habitats worldwide. The ability of environmental policy to address restoration is limited, in part, by uncertainty in the relationships between costly restoration and benefits. Here, we present results from an 18-y field investigation (1990-2007) of submerged aquatic vegetation (SAV) community dynamics and water quality in the Potomac River, a major tributary of the Chesapeake Bay. River and anthropogenic discharges lower water clarity by introducing nutrients that stimulate phytoplankton and epiphyte growth as well as suspended sediments. Efforts to restore the Chesapeake Bay are often viewed as failing. Overall nutrient reduction and SAV restoration goals have not been met. In the Potomac River, however, reduced in situ nutrients, wastewater-treatment effluent nitrogen, and total suspended solids were significantly correlated to increased SAV abundance and diversity. Species composition and relative abundance also correlated with nutrient and water-quality conditions, indicating declining fitness of exotic species relative to native species during restoration. Our results suggest that environmental policies that reduce anthropogenic nutrient inputs do result in improved habitat quality, with increased diversity and native species abundances. The results also help elucidate why SAV cover has improved only in some areas of the Chesapeake Bay.

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

    Science.gov (United States)

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

    2016-06-01

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

  18. The Baltimore Engineers and the Chesapeake Bay, 1961-1987

    Science.gov (United States)

    1988-01-01

    Bay’s ecosystem was still quite sparse, the study provided an overview of the natural and man-made forces operating in the Bay and its watershed and...Susquehanna and Potomac nozzles gushed forth in a large seemingly steady stream while other very small ones dribbled out a stream that was hardly...Engineer District, 1984), p. 11, Table II-I. 5. An excellent brief overview to the Bay’s ecosystem is the U.S. Environmental Protection Agency

  19. Tumor prevalence and biomarkers of genotoxicity in brown bullhead (Ameiurus nebulosus) in Chesapeake Bay tributaries

    Science.gov (United States)

    Pinkney, Alfred E.; Harshbarger, John C.; Karouna-Renier, Natalie K.; Jenko, Kathryn; Balk, Lennart; Skarphéðinsdóttir, Halldora; Liewenborg, Birgitta; Rutter, Michael A.

    2011-01-01

    We surveyed four Chesapeake Bay tributaries for skin and liver tumors in brown bullhead (Ameiurus nebulosus). We focused on the South River, where the highest skin tumor prevalence (53%) in the Bay watershed had been reported. The objectives were to 1) compare tumor prevalence with nearby rivers (Severn and Rhode) and a more remote river (Choptank); 2) investigate associations between tumor prevalence and polynuclear aromatic hydrocarbons (PAHs) and alkylating agents; and 3) statistically analyze Chesapeake Bay bullhead tumor data from 1992 through 2008. All four South River collections exhibited high skin tumor prevalence (19% to 58%), whereas skin tumor prevalence was 2%, 10%, and 52% in the three Severn collections; 0% and 2% in the Choptank collections; and 5.6% in the Rhode collection. Liver tumor prevalence was 0% to 6% in all but one South River collection (20%) and 0% to 6% in the three other rivers. In a subset of samples, PAH-like biliary metabolites and 32P-DNA adducts were used as biomarkers of exposure and response to polycyclic aromatic compounds (PACs). Adducts from alkylating agents were detected as O6-methyl-2'-deoxyguanosine (O6Me-dG) and O6-ethyl-2'-deoxyguanosine (O6Et-dG) modified DNA. Bullheads from the contaminated Anacostia River were used as a positive control for DNA adducts. 32P-DNA adduct concentrations were significantly higher in Anacostia bullhead livers compared with the other rivers. We identified alkyl DNA adducts in bullhead livers from the South and Anacostia, but not the Choptank. Neither the PAH-like bile metabolite data, sediment PAH data, nor the DNA adduct data suggest an association between liver or skin tumor prevalence and exposure to PACs or alkylating agents in the South, Choptank, Severn, or Rhode rivers. Logistic regression analysis of the Chesapeake Bay database revealed that sex and length were significant covariates for liver tumors and length was a significant covariate for skin tumors.

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

    Science.gov (United States)

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

    2015-12-01

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

  1. Ecological Forecasting in Chesapeake Bay: Using a Mechanistic-Empirical Modelling Approach

    Energy Technology Data Exchange (ETDEWEB)

    Brown, C. W.; Hood, Raleigh R.; Long, Wen; Jacobs, John M.; Ramers, D. L.; Wazniak, C.; Wiggert, J. D.; Wood, R.; Xu, J.

    2013-09-01

    The Chesapeake Bay Ecological Prediction System (CBEPS) automatically generates daily nowcasts and three-day forecasts of several environmental variables, such as sea-surface temperature and salinity, the concentrations of chlorophyll, nitrate, and dissolved oxygen, and the likelihood of encountering several noxious species, including harmful algal blooms and water-borne pathogens, for the purpose of monitoring the Bay's ecosystem. While the physical and biogeochemical variables are forecast mechanistically using the Regional Ocean Modeling System configured for the Chesapeake Bay, the species predictions are generated using a novel mechanistic empirical approach, whereby real-time output from the coupled physical biogeochemical model drives multivariate empirical habitat models of the target species. The predictions, in the form of digital images, are available via the World Wide Web to interested groups to guide recreational, management, and research activities. Though full validation of the integrated forecasts for all species is still a work in progress, we argue that the mechanistic–empirical approach can be used to generate a wide variety of short-term ecological forecasts, and that it can be applied in any marine system where sufficient data exist to develop empirical habitat models. This paper provides an overview of this system, its predictions, and the approach taken.

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

    Directory of Open Access Journals (Sweden)

    I. D. Irby

    2015-12-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2007-01-01

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

  5. Temperature and salinity profile data collected from CTD casts by NOAA Ship BAY HYDROGRAPHER in the Chesapeake Bay during survey operations along the NE US coast from 2006-01-05 to 2006-08-28 (NCEI Accession 0014614)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure, salinity, and temperature data were collected from CTD casts from the NOAA Survey Vessel BAY HYDROGRAPHER. Data were collected in the Chesapeake Bay from...

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

    CERN Document Server

    Pluchino, Alessandro; Latora, Vito

    2008-01-01

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

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

    Science.gov (United States)

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

    2001-01-01

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

  8. Methylmercury Cycling and Tidal Exchange in a Chesapeake Bay Salt Marsh (Invited)

    Science.gov (United States)

    Mitchell, C. P.; Jordan, T. E.; Heyes, A.; Gilmour, C. C.

    2010-12-01

    The importance of salt marshes to methylmercury budgets in coastal regions is poorly understood. Given that salt marshes are important coastal features around Chesapeake Bay and in many other coastal areas, and that methylmercury is a bioaccumulated neurotoxin to aquatic biota and the humans that consume them, fully understanding methylmercury sources is an important step in mitigating detrimental health and ecosystem effects. In this research, we highlight the important biogeochemical controls on methylmercury production in a Chesapeake Bay salt marsh and link this production with tidal exchange using hydrological measurements and sampling over a 12-month period. Our findings point to an important linkage between iron cycling and methylmercury production. Net tidal exchange of total mercury and methylmercury showed marked seasonal variation, especially for methylmercury. Overall, we estimate the salt marsh was a large net sink for total mercury (~60 μg m-2 yr-1) and a net source of methylmercury (~0.25 μg m-2 yr-1). In addition to significant in situ methylmercury exposure risk to biota that utilize salt marshes as habitat or breeding grounds, the contribution of methylmercury to the estuarine zone as a result of salt marsh tidal exchange is not negligible.

  9. Interrogation of Chesapeake Bay sediment microbial communities for intrinsic alkane-utilizing potential under anaerobic conditions.

    Science.gov (United States)

    Johnson, Jamie M; Wawrik, Boris; Isom, Catherine; Boling, Wilford B; Callaghan, Amy V

    2015-02-01

    Based on the transient exposure of Chesapeake Bay sediments to hydrocarbons and the metabolic versatility of known anaerobic alkane-degrading microorganisms, it was hypothesized that distinct Bay sediment communities, governed by geochemical gradients, would have intrinsic alkane-utilizing potential under sulfate-reducing and/or methanogenic conditions. Sediment cores were collected along a transect of the Bay. Community DNA was interrogated via pyrosequencing of 16S rRNA genes, PCR of anaerobic hydrocarbon activation genes, and qPCR of 16S rRNA genes and genes involved in sulfate reduction/methanogenesis. Site sediments were used to establish microcosms amended with n-hexadecane under sulfate-reducing and methanogenic conditions. Sequencing of 16S rRNA genes indicated that sediments associated with hypoxic water columns contained significantly greater proportions of Bacteria and Archaea consistent with syntrophic degradation of organic matter and methanogenesis compared to less reduced sediments. Microbial taxa frequently associated with hydrocarbon-degrading communities were found throughout the Bay, and the genetic potential for hydrocarbon metabolism was demonstrated via the detection of benzyl-(bssA) and alkylsuccinate synthase (assA) genes. Although microcosm studies did not indicate sulfidogenic alkane degradation, the data suggested that methanogenic conversion of alkanes was occurring. These findings highlight the potential role that anaerobic microorganisms could play in the bioremediation of hydrocarbons in the Bay.

  10. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Science.gov (United States)

    2010-07-01

    ... to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and..., Virginia; naval firing range. (a) The danger zone. All of the water within a sector extending seaward a...) nautical miles. (3) Firing on the ranges will be suspended as long as any vessel is within the danger...

  11. Scientific Personnel Resource Inventory: List and Index to Research Scientists Involved with the Estuarine Environment, Especially the Chesapeake Bay,

    Science.gov (United States)

    1972-06-01

    including systematics, distribution, and evolution of Pereidae, Hemicamphidae, Belonidae, and Scombridae I -27- NLA I llier, Ries Stuart MS Fishery...invertebrates, especially Kinorhyncha, Priapulida and Tardigrada (24 5Higman, Daniel MS Botanist Chesapeake Bay Center for Environmental Studies Smithsonian...2111 ext.65 B-4, B-5, Community ecology -- Fisheries biology, including community ecology, behavior and systematics -- Zoogeography -- Evolution 406

  12. 33 CFR 165.502 - Safety and Security Zone; Cove Point Liquefied Natural Gas Terminal, Chesapeake Bay, Maryland.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety and Security Zone; Cove Point Liquefied Natural Gas Terminal, Chesapeake Bay, Maryland. 165.502 Section 165.502 Navigation and... Areas Fifth Coast Guard District § 165.502 Safety and Security Zone; Cove Point Liquefied Natural...

  13. 33 CFR 334.370 - Chesapeake Bay, Lynnhaven Roads; danger zones, U.S. Naval Amphibious Base.

    Science.gov (United States)

    2010-07-01

    ...; danger zones, U.S. Naval Amphibious Base. 334.370 Section 334.370 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.370 Chesapeake Bay, Lynnhaven Roads; danger zones, U.S. Naval Amphibious Base....

  14. 33 CFR 165.505 - Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone; Calvert Cliffs Nuclear Power Plant, Chesapeake Bay, Calvert County, Maryland. 165.505 Section 165.505 Navigation and... Areas Fifth Coast Guard District § 165.505 Security Zone; Calvert Cliffs Nuclear Power Plant,...

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

    Directory of Open Access Journals (Sweden)

    Erin A Urquhart

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  18. NOAA Office for Coastal Management Benthic Habitat Data, Catlett and Goodwin Islands on the York River in Chesapeake Bay, VA, 2002-2004 (NODC Accession 0090253)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are a collection of benthic habitat data from studies conducted in the Catlett and Goodwin Islands on the York River in Chesapeake Bay, Virginia in GIS...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  4. The record of major quaternary sea-level changes in a large coastal plain estuary, Chesapeake Bay, Eastern United States

    Science.gov (United States)

    Colman, Steven M.; Mixon, R.B.

    1988-01-01

    Seismic-reflection surveys of the Chesapeake Bay, combined with geologic mapping and analysis of boreholes on the Delmarva Peninsula, provide evidence of at least three generations of the Susquehanna River system and three generations of the Chesapeake Bay. The evidence for ancient courses of the Susquehanna River is preserved as three distinct paleochannels, and evidence for ancient versions of the Chesapeake Bay is preserved as three sets of paleochannel fill beneath the bay and three generations of barrier-spit deposits on the southern Delmarva Peninsula. The paleochannels represent relative sea-level minima and the channel-fill and barrier-spit deposits represents relative sea-level maxima. A history of three major marine transgressions is recorded in the stratigraphy preserved in the filled paleochannels and in the overlying barrier-spit complexes: three systematic progressions from fluvial to estuarine to bay or nearshore marine environments. This sea-level record seems to be compatible with the saw-toothed pattern of the marine oxygen-isotope record and with the concept of glacial-interglacial terminations. It also seems to have a climax character in which most of the preserved evidence is related to the largest terminations and to the extreme sea-level positions that bound those terminations. The three paleochannel-fill and barrier-spit complexes appear to correspond to oxygen-isotope stages 1,5, and either 7 or 11; the three related paleochannels correspond to stages 2, 6, and either 8 or 12. ?? 1988.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-01-01

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

  6. Community implementation dynamics: Nutrient management in the New York City and Chesapeake Bay Watersheds

    Directory of Open Access Journals (Sweden)

    Glenn Earl Sterner

    2015-04-01

    Full Text Available The creation of natural resource management and conservation strategies can be affected by engagement with local citizens and competing interests between agencies and stakeholders at the varying levels of governance. This paper examines the role of local engagement and the interaction between governance levels on the outcomes of nutrient management policy, a specific area of natural resource conservation and management. Presented are two case studies of the New York City and Chesapeake Bay Watersheds in the US. These case studies touch upon the themes of local citizen engagement and governance stakeholder interaction in changing nutrient management to improve water quality. An analysis of these cases leads to several key considerations for the creation and implementation of nutrient management and natural resource management more broadly, including the importance of: local citizen engagement, government brokering and cost sharing; and the need of all stakeholders to respect each other in the policy creation and implementation process.

  7. Identification of largemouth bass virus in the introduced Northern Snakehead inhabiting the Chesapeake Bay watershed.

    Science.gov (United States)

    Iwanowicz, L; Densmore, C; Hahn, C; McAllister, P; Odenkirk, J

    2013-09-01

    The Northern Snakehead Channa argus is an introduced species that now inhabits the Chesapeake Bay. During a preliminary survey for introduced pathogens possibly harbored by these fish in Virginia waters, a filterable agent was isolated from five specimens that produced cytopathic effects in BF-2 cells. Based on PCR amplification and partial sequencing of the major capsid protein (MCP), DNA polymerase (DNApol), and DNA methyltransferase (Mtase) genes, the isolates were identified as Largemouth Bass virus (LMBV). Nucleotide sequences of the MCP (492 bp) and DNApol (419 pb) genes were 100% identical to those of LMBV. The nucleotide sequence of the Mtase (206 bp) gene was 99.5% identical to that of LMBV, and the single nucleotide substitution did not lead to a predicted amino acid coding change. This is the first report of LMBV from the Northern Snakehead, and provides evidence that noncentrarchid fishes may be susceptible to this virus.

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

    Science.gov (United States)

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

    2003-01-01

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

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

    Science.gov (United States)

    Pluchino, A.; Rapisarda, A.; Latora, V.

    2008-10-01

    We have recently introduced [Phys. Rev. E 75, 045102(R) (2007); AIP Conference Proceedings 965, 2007, p. 323] an efficient method for the detection and identification of modules in complex networks, based on the de-synchronization properties (dynamical clustering) of phase oscillators. In this paper we apply the dynamical clustering tecnique to the identification of communities of marine organisms living in the Chesapeake Bay food web. We show that our algorithm is able to perform a very reliable classification of the real communities existing in this ecosystem by using different kinds of dynamical oscillators. We compare also our results with those of other methods for the detection of community structures in complex networks.

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

    Energy Technology Data Exchange (ETDEWEB)

    Blazer, Vicki S., E-mail: Vblazer@usgs.gov [U.S. Geological Survey, National Fish Health Research Laboratory, Leetown Science Center, 11649 Leetown Road, Kearneysville, WV 25430 (United States); Pinkney, Alfred E., E-mail: Fred_Pinkeny@fws.gov [U.S. Fish and Wildlife Service, Chesapeake Bay Field Office, 177 Admiral Cochrane Drive, Annapolis, MD 21401 (United States); Jenkins, Jill A., E-mail: jenkinsj@usgs.gov [U.S. Geological Survey, National Wetlands Research Center, 700 Cajundome Blvd., Lafayette, LA 70506 (United States); Iwanowicz, Luke R., E-mail: Liwanowicz@usgs.gov [U.S. Geological Survey, National Fish Health Research Laboratory, Leetown Science Center, 11649 Leetown Road, Kearneysville, WV 25430 (United States); Minkkinen, Steven, E-mail: steve_minkkinen@fws.gov [U.S. Fish and Wildlife Service, Chesapeake Bay Field Office, 177 Admiral Cochrane Drive, Annapolis, MD 21401 (United States); Draugelis-Dale, Rassa O., E-mail: daler@usgs.gov [U.S. Geological Survey, National Wetlands Research Center, 700 Cajundome Blvd., Lafayette, LA 70506 (United States); Uphoff, James H., E-mail: juphoff@dnr.state.md.us [Maryland Department of Natural Resources, Fisheries Service, Cooperative Oxford Laboratory, 904 South Morris Street, Oxford, MD 21654 (United States)

    2013-03-01

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

  11. The bioeconomic impact of different management regulations on the Chesapeake Bay blue crab fishery

    Science.gov (United States)

    Bunnell, David B.; Lipton, Douglas W.; Miller, Thomas J.

    2010-01-01

    The harvest of blue crabs Callinectes sapidus in Chesapeake Bay declined 46% between 1993 and 2001 and remained low through 2008. Because the total market value of this fishery has declined by an average of US $ 3.3 million per year since 1993, the commercial fishery has been challenged to maintain profitability. We developed a bioeconomic simulation model of the Chesapeake Bay blue crab fishery to aid managers in determining which regulations will maximize revenues while ensuring a sustainable harvest. We compared 15 different management scenarios, including those implemented by Maryland and Virginia between 2007 and 2009, that sought to reduce female crab harvest and nine others that used seasonal closures, different size regulations, or the elimination of fishing for specific market categories. Six scenarios produced the highest revenues: the 2008 and 2009 Maryland regulations, spring and fall closures for female blue crabs, and 152- and 165-mm maximum size limits for females. Our most important finding was that for each state the 2008 and 2009 scenarios that implemented early closures of the female crab fishery produced higher revenues than the 2007 scenario, in which no early female closures were implemented. We conclude that the use of maximum size limits for female crabs would not be feasible despite their potentially high revenue, given the likelihood that the soft-shell and peeler fisheries cannot be expanded beyond their current capacity and the potentially high mortality rate for culled individuals that are the incorrect size. Our model results support the current use of seasonal closures for females, which permit relatively high exploitation of males and soft-shell and peeler blue crabs (which have high prices) while keeping the female crab harvest sustainable. Further, our bioeconomic model allows for the inclusion of an economic viewpoint along with biological data when target reference points are set by managers.

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

    Science.gov (United States)

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

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Mary Anne; Scavia, Donald, E-mail: mevans@umich.edu, E-mail: scavia@umich.edu [School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI 48109 (United States)

    2011-01-15

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

  14. Production and Field Planting of Vegetative Propagules for Restoration of Redhead Grass and Sago Pondweed in Chesapeake Bay

    Science.gov (United States)

    2009-08-01

    1997). Most SAV species reproduce both sexually (flower, pollen , fruit, and seed) and asexually (clonally) for population expansion and long-term...perfoliatus produce abundant seeds (e.g., Yeo 1966; Ailstock and Shafer 2004), seed viability and germination success tend to be relatively low under most...technical note describes techniques for restoring P. perfoliatus and S. pecti- nata in the mesohaline region of Chesapeake Bay through the use of over

  15. Assimilation of HF Radar Observations in the Chesapeake-Delaware Bay Region Using the Navy Coastal Ocean Model (NCOM) and the Four-Dimensional Variational (4DVAR) Method

    Science.gov (United States)

    2015-01-01

    Assimilation of HF Radar Observations in the C h esa pea ke-Delawa re Bay Region Using the Navy Coastal Ocean Model (NCOM) and the Four...376 4. The Assimilation System ........... ................ .............................. ........ .... .... ............ 377 5...TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Assimilation of HF Radar Observations in the Chesapeake-Delaware Bay region

  16. Shipboard magnetic field "noise" reveals shallow heavy mineral sediment concentrations in Chesapeake Bay

    Science.gov (United States)

    Shah, Anjana K.; Vogt, Peter R.; Rosenbaum, Joseph G.; Newell, Wayne; Cronin, Thomas M.; Willard, Debra A.; Hagen, Rick A.; Brozena, John; Hofstra, Albert

    2012-01-01

    Shipboard magnetic field data collected over Chesapeake Bay exhibit low-amplitude, short-wavelength anomalies that most likely indicate shallow concentrations of heavy mineral sediments. Piston core layers and black sand beach samples exhibit enhanced magnetic susceptibilities and carry remanent magnetization, with mineralogical analyses indicating ilmenite and trace magnetite and/or maghemite and hematite. The anomalies are subtle and would be filtered as noise using traditional approaches, but can instead be highlighted using spectral methods, thus providing nearly continuous coverage along survey tracks. The distribution of the anomalies provides constraints on relevant sorting mechanisms. Comparisons to sonar data and previous grab samples show that two of three areas surveyed exhibit short-wavelength anomalies that are clustered over sand-covered areas, suggesting initial sorting through settling mechanisms. This is supported by a correlation between core magnetic susceptibility and grain size. Near the Choptank River, where sediment resuspension is wave-dominated, anomalies show a sharp decrease with seafloor depth that cannot be explained by signal attenuation alone. In Pocomoke Sound, where both tidal currents and wave-action impact sediment resuspension, anomalies show a more gradual decrease with depth. Near the mouth of the bay, where there is a higher influx of sediments from the continental shelf, short-wavelength anomalies are isolated and do not appear to represent heavy mineral sand concentrations. These combined observations suggest the importance of further sorting by erosional processes in certain parts of the bay. Additionally, comparisons of these data to cores sampling pre-Holocene sediments suggest that the sorting of heavy minerals in higher energy, shallow water environments provides a mechanism for correlations between core magnetic susceptibility and sea-level changes.

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

    Science.gov (United States)

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

    2013-01-01

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

  18. Estimation of regional hydrogeological properties for use in a hydrologic model of the Chesapeake Bay watershed

    Science.gov (United States)

    Seck, A.; Welty, C.

    2012-12-01

    Characterization of subsurface hydrogeologic properties in three dimensions and at large scales for use in groundwater flow models can remain a challenge owing to the lack of regional data sets and scatter in coverage, type, and format of existing small-scale data sets. This is the case for the Chesapeake Bay watershed, where numerous studies have been carried out to quantify groundwater processes at small scales but limited information is available on subsurface characteristics and groundwater fluxes at regional scales. One goal of this work is to synthesize disparate information on subsurface properties for the Chesapeake Bay watershed for use in a 3D integrated ParFlow model over an area of 400,000 km2 with a horizontal resolution of 1 km and a vertical resolution of 5 m. We combined different types of data at various scales to characterize hydrostratigraphy and hydrogeological properties. The conceptual hydrogeologic model of the study area is composed of two major regions. One region extends from the Valley and Ridge physiographic province south of New York to the Piedmont physiographic province in Maryland and Virginia. This region is generally characterized by fractured rock overlain by a mantle of regolith. Soil thickness and hydraulic conductivity values were obtained from the U.S. General Soil Map (STATSGO2). Saprolite thickness was evaluated using casing depth information from well completion reports from four state agencies. Geostatistical methods were used to generalize point data to the model extent and resolution. A three-dimensional hydraulic conductivity field for fractured bedrock was estimated using a published national map of permeability and depth- varying functions from literature. The Coastal Plain of Maryland, Virginia, Delaware and New Jersey constitutes the second region and is characterized by layered sediments. In this region, the geometry of 20 aquifers and confining units was constructed using interpolation of published contour maps of

  19. Interaction of Students and Scientists in the Chesapeake Bay Watershed Education and Training and Emerging Scientist Programs

    Science.gov (United States)

    Bieri, J.; Sprague, S.; Bloch, N.; Laubhan, S.

    2006-05-01

    NOAA's Chesapeake Bay Office (NCBO) is actively engaged in K-12 science education within the Chesapeake Bay watershed. Through the Bay Watershed Education and Training Program (B-WET) and the Emerging Scientist Project, we are furthering the Chesapeake Bay Program (CBP) goal of providing a meaningful watershed experience for every student prior to their graduation from high school. These projects seek to provide field experiences for students coupled with both pre-experience and post-experience integration in the classroom. In many cases, NCBO funded projects partner school educators with the scientific community. Partnering scientists assist teachers with resources in the field, classroom and on-line. In many cases, students are actively engaged in data collection (fish or invertebrate species data, water quality parameters, other physical site specific data) that can be incorporated into the partnering scientists existing data bases. Scientists are able to increase their database while at the same time provide teachers and students with a meaningful field experience that exposes students to authentic research and field sampling. This type of field experience lends itself nicely to applicable follow-up activites and analysis back in the classroom. Students may take this "real data" and use for discussion of application of management decisions and/or actually implement changes within their community (i.e. restoration projects). This presentation will highlight several B- WET projects as well as the ESP that have succeeded in engaging a K-12 audience in authentic science. Scientific partners include the Smithsonian Environmental Research Consortium (SERC), the University of Maryland (UMD) and the Virginia Institute of Marine Science (VIMS).

  20. Monoclinic tridymite in clast-rich impact melt rock from the Chesapeake Bay impact structure

    Science.gov (United States)

    Jackson, J.C.; Horton, J.W.; Chou, I.-Ming; Belkin, H.E.

    2011-01-01

    X-ray diffraction and Raman spectroscopy confirm a rare terrestrial occurrence of monoclinic tridymite in clast-rich impact melt rock from the Eyreville B drill core in the Chesapeake Bay impact structure. The monoclinic tridymite occurs with quartz paramorphs after tridymite and K-feldspar in a microcrystalline groundmass of devitrified glass and Fe-rich smectite. Electron-microprobe analyses revealed that the tridymite and quartz paramorphs after tridymite contain different amounts of chemical impurities. Inspection by SEM showed that the tridymite crystal surfaces are smooth, whereas the quartz paramorphs contain irregular tabular voids. These voids may represent microporosity formed by volume decrease in the presence of fluid during transformation from tridymite to quartz, or skeletal growth in the original tridymite. Cristobalite locally rims spherulites within the same drill core interval. The occurrences of tridymite and cristobalite appear to be restricted to the thickest clast-rich impact melt body in the core at 1402.02-1407.49 m depth. Their formation and preservation in an alkali-rich, high-silica melt rock suggest initially high temperatures followed by rapid cooling.

  1. Contamination assessment in microbiological sampling of the Eyreville core, Chesapeake Bay impact structure

    Science.gov (United States)

    Gronstal, A.L.; Voytek, M.A.; Kirshtein, J.D.; Von der, Heyde; Lowit, M.D.; Cockell, C.S.

    2009-01-01

    Knowledge of the deep subsurface biosphere is limited due to difficulties in recovering materials. Deep drilling projects provide access to the subsurface; however, contamination introduced during drilling poses a major obstacle in obtaining clean samples. To monitor contamination during the 2005 International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) deep drilling of the Chesapeake Bay impact structure, four methods were utilized. Fluorescent microspheres were used to mimic the ability of contaminant cells to enter samples through fractures in the core material during retrieval. Drilling mud was infused with a chemical tracer (Halon 1211) in order to monitor penetration of mud into cores. Pore water from samples was examined using excitation-emission matrix (EEM) fl uorescence spectroscopy to characterize dissolved organic carbon (DOC) present at various depths. DOC signatures at depth were compared to signatures from drilling mud in order to identify potential contamination. Finally, microbial contaminants present in drilling mud were identified through 16S ribosomal deoxyribonucleic acid (rDNA) clone libraries and compared to species cultured from core samples. Together, these methods allowed us to categorize the recovered core samples according to the likelihood of contamination. Twenty-two of the 47 subcores that were retrieved were free of contamination by all the methods used and were subsequently used for microbiological culture and culture-independent analysis. Our approach provides a comprehensive assessment of both particulate and dissolved contaminants that could be applied to any environment with low biomass. ?? 2009 The Geological Society of America.

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

    Science.gov (United States)

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

    2010-01-01

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

  3. Derelict fishing gear in Chesapeake Bay, Virginia: spatial patterns and implications for marine fauna.

    Science.gov (United States)

    Bilkovic, Donna Marie; Havens, Kirk; Stanhope, David; Angstadt, Kory

    2014-03-15

    Derelict fishing gear is a source of mortality for target and non-target marine species. A program employing commercial watermen to remove marine debris provided a novel opportunity to collect extensive spatially-explicit information for four consecutive winters (2008-2012) on the type, distribution, and abundance of derelict fishing gear and bycatch in Virginia waters of Chesapeake Bay. The most abundant form of derelict gear recovered was blue crab pots with almost 32,000 recovered. Derelict pots were widely distributed, but with notable hotspot areas, capturing 40 species and over 31,000 marine organisms. The target species, blue crab, experienced the highest mortality from lost pots with an estimated 900,000 animals killed each year, a potential annual economic loss to the fishery of $300,000. Important fishery species were captured and killed in derelict pots including Atlantic croaker and black sea bass. While some causes of gear loss are unavoidable, others can be managed to minimize loss.

  4. Proposed tethered unmanned aerial system for the detection of pollution entering the Chesapeake Bay area

    Science.gov (United States)

    Goodman, J.; McKay, J.; Evans, W.; Gadsden, S. Andrew

    2016-05-01

    This paper is based on a proposed unmanned aerial system platform that is to be outfitted with high-resolution sensors. The proposed system is to be tethered to a moveable ground station, which may be a research vessel or some form of ground vehicle (e.g., car, truck, or rover). The sensors include, at a minimum: camera, infrared sensor, thermal, normalized difference vegetation index (NDVI) camera, global positioning system (GPS), and a light-based radar (LIDAR). The purpose of this paper is to provide an overview of existing methods for pollution detection of failing septic systems, and to introduce the proposed system. Future work will look at the high-resolution data from the sensors and integrating the data through a process called information fusion. Typically, this process is done using the popular and well-published Kalman filter (or its nonlinear formulations, such as the extended Kalman filter). However, future work will look at using a new type of strategy based on variable structure estimation for the information fusion portion of the data processing. It is hypothesized that fusing data from the thermal and NDVI sensors will be more accurate and reliable for a multitude of applications, including the detection of pollution entering the Chesapeake Bay area.

  5. Experimental alteration of artificial and natural impact melt rock from the Chesapeake Bay impact structure

    Science.gov (United States)

    Declercq, J.; Dypvik, H.; Aagaard, P.; Jahren, J.; Ferrell, R.E.; Horton, J. Wright

    2009-01-01

    The alteration or transformation of impact melt rock to clay minerals, particularly smectite, has been recognized in several impact structures (e.g., Ries, Chicxulub, Mj??lnir). We studied the experimental alteration of two natural impact melt rocks from suevite clasts that were recovered from drill cores into the Chesapeake Bay impact structure and two synthetic glasses. These experiments were conducted at hydrothermal temperature (265 ??C) in order to reproduce conditions found in meltbearing deposits in the first thousand years after deposition. The experimental results were compared to geochemical modeling (PHREEQC) of the same alteration and to original mineral assemblages in the natural melt rock samples. In the alteration experiments, clay minerals formed on the surfaces of the melt particles and as fine-grained suspended material. Authigenic expanding clay minerals (saponite and Ca-smectite) and vermiculite/chlorite (clinochlore) were identified in addition to analcime. Ferripyrophyllite was formed in three of four experiments. Comparable minerals were predicted in the PHREEQC modeling. A comparison between the phases formed in our experiments and those in the cores suggests that the natural alteration occurred under hydrothermal conditions similar to those reproduced in the experiment. ?? 2009 The Geological Society of America.

  6. Chronicling long-term predator responses to a shifting forage base in Chesapeake Bay: an energetics approach

    Science.gov (United States)

    Overton, Anthony S.; Griffin, Jennifer C.; Margraf, F. Joseph; May, Eric B.; Hartman, Kyle J.

    2015-01-01

    The population of Striped Bass Morone saxatilis in Chesapeake Bay has increased significantly since the 1980s because of management efforts while the relative abundance of some key prey fish has declined since the 1970s. We examined the trophic interactions and prey consumption patterns of Striped Bass in Chesapeake Bay to determine how Striped Bass have responded to changing prey resources. Seasonal diet, growth, and thermal data were collected from 1955 to 1959, 1990 to 1992, and 1998 to 2001; these data were coupled with a bioenergetics model approach to characterize temporal patterns in prey consumption for Striped Bass. The estimates were compared across each period to build a historical prey consumption profile from 1955 to 2001. Prey consumption dynamics for Striped Bass have changed dramatically between 1955 and 2001. In general, Striped Bass in the early and late 1990s consumed less Atlantic Menhaden Brevoortia tyranus and more Bay Anchovy Anchoa mitchilli than during the 1950s. The largest differences in consumption were observed in the younger age-classes. During 1998–2001, age-1 and age-2 Striped Bass consumed, respectively, 15.5 and 11.9 times less Atlantic Menhaden than during the 1950sand 12.2 and 7.2 less than during 1990–1992. Bay Anchovy were almost absent in the diet of bass age 3 and older during the 1950s but were consumed by the age-3+ group during 1990–1992 and to a greater extent during 1998–2001. Age-3+ Striped Bass during 1998–2001, on average, consumed twice as much Bay Anchovy than during 1990–1992. Blue crab Callinectes sappidus were consumed only by age 2 in the 1950s and 1990–1992 and by ages 2 and older in 1998–2001. Age-2 bass consumed 8.8 more blue crab in 1990–1992 and 7.5 times more in 1998–2001 than during the 1950s. The patterns in the consumption of Atlantic Menhaden coincided with increased consumption of Bay Anchovy and blue crab, possibly as a result of the declines in Atlantic Menhaden

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

    Science.gov (United States)

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

    2011-12-01

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

  8. A 3D, cross-scale, baroclinic model with implicit vertical transport for the Upper Chesapeake Bay and its tributaries

    Science.gov (United States)

    Ye, Fei; Zhang, Yinglong J.; Friedrichs, Marjorie A. M.; Wang, Harry V.; Irby, Isaac D.; Shen, Jian; Wang, Zhengui

    2016-11-01

    We develop a new vertically implicit transport solver, based on two total variation diminishing (TVD) limiters in space and time, inside a 3D unstructured-grid model (SCHISM), and apply it to the Upper Chesapeake Bay (UCB), which has complex geometry and sharp pycnocline. We show that the model is able to accurately and efficiently capture the elevation, velocity, salinity and temperature in both the deep and shallow regions of UCB. Compared with all available CTD casts, the overall model skills have the mean absolute error of 1.08 PSU and 0.85 °C, and correlation coefficient of 0.97 and 0.99 for salinity and temperature respectively. More importantly, the new implicit solver better captures the density stratification, which has great implications on biogeochemistry in this estuarine system. The cross-scale capability of the model is demonstrated by extending the high-resolution grids into a tributary (Chester River) and its sub-tributary (Corsica River), with minimal impact on the model efficiency. The model is also able to capture complex 3D structures at the transition zone between the main bay and the tributary, including the three-layered circulation in Baltimore Harbor. As more and more attention is being paid to the productive shallows in the Chesapeake Bay and other estuaries, the model can serve as a very powerful management tool to understand the impact of both local and remote forcing functions.

  9. Restoration of waterbird habitats in Chesapeake Bay: Great expectations or Sisyphus revisited?

    Science.gov (United States)

    Erwin, R.M.; Beck, R.A.; Erwin, R. Michael; Watts, Bryan D.; Haramis, G.Michael; Perry, Matthew C.; Hobson, Keith A.

    2007-01-01

    In the past half century, many waterbird populations in Chesapeake Bay have declined or shifted ranges, indicating major ecological changes have occurred. While many studies have focused on the problems associated with environmental degradation such as the losses of coastal wetlands and submerged vegetation, a number of restoration efforts have been launched in the past few decades to reverse the 'sea of despair.' Most pertinent to waterbirds, restoration of submerged aquatic vegetation (SAV) beds, tidal wetland restoration, oyster reef restoration, and island creation/restoration have benefited a number of species. State and federal agencies and non government agencies have formed partnerships to spawn many projects ranging in size from less than 0.5 ha to ca. 1,000 ha. While most SAV, wetland, and oyster reef projects have struggled to different degrees over the past ten to twenty years with inconsistent methods, irregular monitoring, and unknown reasons for failures, recent improvements in techniques and application of adaptive management have been made. The large dredge-material island at Hart-Miller Island near Baltimore, Poplar Island west of Tilghman Island, Maryland, and Craney Island Portsmouth, Virginia have provided large outdoor 'laboratories' for wildlife, fishery, and wetland habitat creation. All three have proven to be important for nesting waterbirds and migrant shorebirds and waterfowl; however nesting populations at all three islands have been compromised to different degrees by predators. Restoration success for waterbirds and other natural resources depends on: (1) establishing realistic, quantifiable objectives and performance criteria, (2) continued monitoring and management (e.g., predator control), (3) targeted research to determine causality, and (4) careful evaluation under an adaptive management regime.

  10. Chesapeake Bay impact structure: Morphology, crater fill, and relevance for impact structures on Mars

    Science.gov (United States)

    Horton, J.W.; Ormo, J.; Powars, D.S.; Gohn, G.S.

    2006-01-01

    The late Eocene Chesapeake Bay impact structure (CBIS) on the Atlantic margin of Virginia is one of the largest and best-preserved "wet-target" craters on Earth. It provides an accessible analog for studying impact processes in layered and wet targets on volatile-rich planets. The CBIS formed in a layered target of water, weak clastic sediments, and hard crystalline rock. The buried structure consists of a deep, filled central crater, 38 km in width, surrounded by a shallower brim known as the annular trough. The annular trough formed partly by collapse of weak sediments, which expanded the structure to ???85 km in diameter. Such extensive collapse, in addition to excavation processes, can explain the "inverted sombrero" morphology observed at some craters in layered targets. The distribution of crater-fill materials i n the CBIS is related to the morphology. Suevitic breccia, including pre-resurge fallback deposits, is found in the central crater. Impact-modified sediments, formed by fluidization and collapse of water-saturated sand and silt-clay, occur in the annular trough. Allogenic sediment-clast breccia, interpreted as ocean-resurge deposits, overlies the other impactites and covers the entire crater beneath a blanket of postimpact sediments. The formation of chaotic terrains on Mars is attributed to collapse due to the release of volatiles from thick layered deposits. Some flat-floored rimless depressions with chaotic infill in these terrains are impact craters that expanded by collapse farther than expected for similar-sized complex craters in solid targets. Studies of crater materials in the CBIS provide insights into processes of crater expansion on Mars and their links to volatiles. ?? The Meteoritical Society, 2006.

  11. Sediment Retention Dynamics and Vegetation Along Three Tributaries of the Chesapeake Bay

    Science.gov (United States)

    Ross, K.; Ross, K.; Hupp, C.; Alexander, L.; Alexander, L.

    2001-12-01

    Coastal Plain riparian wetlands in the Mid-Atlantic United States are the last place for sediment and contaminant storage before reaching critical estuarine and marine environments. The deteriorating health of the Chesapeake Bay has been attributed in part to elevated sediment loads. The purpose of this study is to investigate the effects of channelization and urbanization on sediment deposition and geomorphic processes along the Pocomoke and Chickahominy Rivers and Dragon Run, three Coastal Plain tributaries. Floodplain microtopography was surveyed in 100 x 100 m grids at three characteristic reaches along each river and woody vegetation analyses were conducted. Floodplain suspended sediment concentrations and short and long-term sedimentation rates were estimated at each reach using single stage sediment sampler arrays, clay pads and dendrogeomorphic techniques, respectively. Site hydroperiod and flow characteristics were determined from USGS gaging station records, floodplain water level recorders, and field observations. Channelized floodplain reaches along the Pocomoke River are flooded less frequently, have lower mineral sedimentation rates (2 mm/yr to 6 mm/yr) and woody species diversity than the unchannelized reaches. Along the Chickahominy River, floodplain wetlands close to urban centers are flooded more frequently, but have shorter hydroperiods (3.5 days/yr compared to more than 45 days/yr), lower sedimentation rates (1.8 mm/yr to 6.8 mm/yr), and lower woody species diversity (0.51 to 1.95 on the Shannon-Weiner diversity index) than floodplains further downstream. Suspended sediment delivery and deposition rates are significantly influenced by floodplain hydroperiod duration and channel-floodplain connectivity. These results suggest that understanding floodplain sediment dynamics and geomorphic processes with respect to dominant watershed landuse patterns is critical for effective water quality management and restoration efforts.

  12. Bio-optics of the Chesapeake Bay from measurements and radiative transfer closure

    Science.gov (United States)

    Tzortziou, Maria; Herman, Jay R.; Gallegos, Charles L.; Neale, Patrick J.; Subramaniam, Ajit; Harding, Lawrence W., Jr.; Ahmad, Ziauddin

    2006-06-01

    We combined detailed bio-optical measurements and radiative transfer modeling to perform an 'optical closure' experiment for an optically complex and biologically productive region of the Chesapeake Bay. We used this experiment to evaluate certain assumptions commonly used in bio-optical models, and to investigate which optical characteristics are most important to accurately model and interpret remote sensing ocean-color observations in these Case 2 waters. Direct measurements were made of the magnitude, variability, and spectral characteristics of backscattering and absorption that are critical for accurate parameterizations in satellite bio-optical algorithms and underwater radiative transfer simulations. We found that the ratio of backscattering to total scattering (i.e. the backscattering fraction, bb/ b) varied considerably depending on particulate loading, distance from land, and mixing processes, and had an average value of 0.0128 at 530 nm. Incorporating information on the magnitude, variability, and spectral characteristics of particulate backscattering into the radiative transfer model, rather than using a volume scattering function commonly assumed for turbid waters, was critical to obtaining agreement between model calculations and measured radiometric quantities. In-situ measurements of absorption coefficients need to be corrected for systematic overestimation due to scattering errors, and this correction commonly employs the assumption that absorption by particulate matter at near-infrared wavelengths is zero. Direct measurements, however, showed that particulate matter in the Bay had small, but non-zero, absorption in the 700-730 nm wavelength region. Accounting for this residual particulate absorption when correcting in-situ measured absorption spectra for scattering errors was important in model simulations of water reflectance in the green wavelengths, where reflectance spectra in estuarine waters peak. Sun-induced chlorophyll fluorescence

  13. Long-term changes in sediment and nutrient delivery from Conowingo Dam to Chesapeake Bay: Effects of reservoir sedimentation

    Science.gov (United States)

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

    2016-01-01

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

  14. δ15N Values in Crassostrea virginica Shells Provides Early Direct Evidence for Nitrogen Loading to Chesapeake Bay

    Science.gov (United States)

    Black, H. D.; Andrus, C. F. T.; Lambert, W. J.; Rick, T. C.; Gillikin, D. P.

    2017-01-01

    Crassostrea virginica is one of the most common estuarine bivalves in the United States’ east coast and is frequently found in archaeological sites and sub-fossil deposits. Although there have been several sclerochronological studies on stable carbon and oxygen isotopes in the shells of this species, less is known about δ15N values within their shells, which could be a useful paleoenvironmental proxy to assess estuarine nitrogen dynamics. Modern C. virginica samples were collected in Chesapeake Bay for comparison with archaeological shells from nearby sites ranging in age from ~100 to 3,200 years old. Left valves were sampled by milling the hinge area and the resulting powder was analyzed for %N and δ15N values. Comparison of δ15N values between C. virginica shells shows relatively constant values from ~1250 BC to ~1800 AD. After ~1800 AD, there are rapid increases in 15N enrichment in the shells, which continue to increase in value up to the modern shell values. The increase in δ15N values is evidence of early anthropogenic impact in Chesapeake Bay. These results corroborate the observation that coastal nitrogen pollution occurred earlier than the 19th century and support the use of oyster shell δ15N values as a useful environmental proxy. PMID:28281649

  15. Remote sensing of particle backscattering in Chesapeake Bay: a 6-year SeaWiFS retrospective view

    Science.gov (United States)

    Zawada, D.G.; Hu, C.; Clayton, T.; Chen, Z.; Brock, J.C.; Muller-Karger, F. E.

    2007-01-01

    Traditional field techniques to monitor water quality in large estuaries, such as boat-based surveys and autonomous moored sensors, generally provide limited spatial coverage. Satellite imagery potentially can be used to address both of these limitations. Here, we show that satellite-based observations are useful for inferring total-suspended-solids (TSS) concentrations in estuarine areas. A spectra-matching optimization algorithm was used to estimate the particle backscattering coefficient at 400 nm, bbp(400), in Chesapeake Bay from Sea-viewing Wide-Field-of-view Sensor (SeaWiFS) satellite imagery. These estimated values of bbp(400) were compared to in situ measurements of TSS for the study period of September 1997–December 2003. Contemporaneous SeaWiFS bbp(400) values and TSS concentrations were positively correlated (N = 340, r2 = 0.4, P bp(400) values served as a reasonable first-order approximation for synoptically mapping TSS. Overall, large-scale patterns of SeaWiFS bbp(400) appeared to be consistent with expectations based on field observations and historical reports of TSS. Monthly averages indicated that SeaWiFS bbp(400) was typically largest in winter (>0.049 m−1, November–February) and smallest in summer (−1, June–August), regardless of the amount of riverine discharge to the bay. The study period also included Hurricanes Floyd and Isabel, which caused large-scale turbidity events and changes in the water quality of the bay. These results demonstrate that this technique can provide frequent synoptic assessments of suspended solids concentrations in Chesapeake Bay and other coastal regions.

  16. Evaluation of Salinity-Related Habitat Impacts in the Lower Chesapeake Bay and James River for the Norfolk Harbor and Channels Deepening Study.

    Science.gov (United States)

    1984-10-01

    and by two protozoan parasites , Minchinia nelsoni ("MSX") and Perkinsus marinus ("dermo"). Salinity Relationships - Crassostrea virginica is an...affecting density and abundance of oysters in Chesapeake Bay are predation and disease (actually, protozoan parasites ). Minchinia nelsoni ("MSX") was

  17. Study of the possible role of pollution in the prevalence of sea nettles in the Chesapeake Bay and the development of a census taking method

    Science.gov (United States)

    1971-01-01

    A study of the effect of pollutants on the sea nettle population of Chesapeake Bay was conducted. The effects of pollutants on the polyp stage of the nettle were stressed. Methods of detecting adult sea nettles by remote sensing are discussed. The effects of phosphate, nitrate, ammonium, and combinations of these pollutants were investigated.

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

    Energy Technology Data Exchange (ETDEWEB)

    Taft, J.L.

    1976-04-01

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

  19. OYSTER POPULATUION ESTIMATION IN SUPPORT OF THE TEN-YEAR GOAL FOR OYSTER RESOTRATION IN THE CHESAPEAKE BAY: DEVELOPING STRATEGIES FOR RESTORING AND MANAGING THE EASTERN OYSTER

    Science.gov (United States)

    Mann, Roger, Steve Jordan, Gary Smith, Kennedy Paynter, James Wesson, Mary Christman, Jessica Vanisko, Juliana Harding, Kelly Greenhawk and Melissa Southworth. 2003. Oyster Population Estimation in Support of the Ten-Year Goal for Oyster Restoration in the Chesapeake Bay: Develop...

  20. NODC Standard Product: Coastal Change Analysis Program (C-CAP) Chesapeake Bay Region Data from 1984 to 1989 on CD-ROM (NODC Accession 9200303)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data set on this CD-ROM shows changes in land cover for the Chesapeake Bay region over the 5-year interval from 1984 to 1988-89. The data set was produced...

  1. Nutrient and Sediment Reductions from Algal Flow-Way Technologies: Recommendations to the Chesapeake Bay Program's Water Quality Goal Implementation Team from the Algal Flow-Way Technologies BMP Expert Panel

    Science.gov (United States)

    The Chesapeake Stormwater Network hosted a workshop on July, 2012 to discuss the potential nutrient reductions from emerging stormwater technologies including algal flow-way technologies (AFTs). Workshop participants recommended the Chesapeake Bay Program’s Water Quality Goal Implementation Team(WQ...

  2. Tracking Nonpoint Source Nitrogen and Carbon in Watersheds of Chesapeake Bay

    Science.gov (United States)

    Kaushal, S.; Pennino, M. J.; Duan, S.; Blomquist, J.

    2012-12-01

    Humans have altered nitrogen and carbon cycles in rivers regionally with important impacts on coastal ecosystems. Nonpoint source nitrogen pollution is a leading contributor to coastal eutrophication and hypoxia. Shifts in sources of carbon impact downstream ecosystem metabolism and fate and transport of contaminants in coastal zones. We used a combination of stable isotopes and optical tracers to investigate fate and transport of nitrogen and carbon sources in tributaries of the largest estuary in the U.S., the Chesapeake Bay. We analyzed isotopic composition of water samples from major tributaries including the Potomac River, Susquehanna River, Patuxent River, and Choptank River during routine and storm event sampling over multiple years. A positive correlation between δ15N-NO3- and δ18O-NO3- in the Potomac River above Washington D.C. suggested denitrification or biological uptake in the watershed was removing agriculturally-derived N during summer months. In contrast, the Patuxent River in Maryland showed elevated δ15N-NO3- (5 - 12 per mil) with no relationship to δ18O-NO3- suggesting the importance of wastewater sources. From the perspective of carbon sources, there were distinct isotopic values of the δ13C-POM of particulate organic matter and fluorescence excitation emission matrices (EEMS) for rivers influenced by their dominant watershed land use. EEMS showed that there were increases in the humic and fulvic fractions of dissolved organic matter during spring floods, particularly in the Potomac River. Stable isotopic values of δ13C-POM also showed rapid depletion suggesting terrestrial carbon "pulses" in the Potomac River each spring. The δ15N-POM peaked to 10 - 15 per mil each spring suggested a potential manure source or result of biological processing within the watershed. Overall, there were considerable changes in sources and transformations of nitrogen and carbon that varied across rivers and that contribute to nitrogen and carbon loads

  3. Societal Implications of an Impact Crater - Chesapeake Bay Impact Structure, Virginia

    Science.gov (United States)

    Emry, S.; McFarland, R.; Powars, D.

    2002-05-01

    Ground water plays an important role in the economy and quality of life in the Coastal Plain of Virginia. In 1990, the aquifers in the Coastal Plain supplied over 100 million gallons of water per day to the citizens, businesses, and industries of Virginia. In southeastern Virginia, the thirteen public water utilities serve approximately 1.5 million people in the Hampton Roads area. The role of ground water resources in sustaining this area is more critical than ever due to the relatively low relief of the Coastal Plain Province, providing few new surface water sources to meet the growing population and expanding economy and the increased regulatory obstacles to obtaining a permit to build new reservoirs. A zone of salty ground water, referred to as the "inland salt water wedge," is well known to ground water resource planners and scientists, but until recently the phenomenon has not been satisfactorily explained. In 1996, the directors of the water utilities in Hampton Roads were introduced to the most dramatic geological event that ever took place in the Chesapeake Bay region. Geologists from the U.S. Geological Survey provided evidence of a meteor impact that formed a crater over 35 million years ago. The contours of the inland saltwater wedge conform well to the shape of the crater's outer rim. Prior to the discovery of the impact crater, it was presumed that the ground water flow in the Coastal Plain aquifer system was a relatively simple system described as "alternating layers of aquifers and confining units gradually dipping and thickening from the west to the east." With the discovery of the impact crater, the rules changed. In 1997, the USGS and the Hampton Roads Planning District Commission, representing the sixteen member jurisdictions, teamed up in a cooperative effort to redefine the hydrogeology of southeastern Virginia. In 1999, the Virginia Department of Environmental Quality and the Virginia Department of Mines, Minerals, and Energy joined the team

  4. Spatial Predictive Modeling and Remote Sensing of Land Use Change in the Chesapeake Bay Watershed

    Science.gov (United States)

    Goetz, Scott J.; Bockstael, Nancy E.; Jantz, Claire A.

    2005-01-01

    This project was focused on modeling the processes by which increasing demand for developed land uses, brought about by changes in the regional economy and the socio-demographics of the region, are translated into a changing spatial pattern of land use. Our study focused on a portion of the Chesapeake Bay Watershed where the spatial patterns of sprawl represent a set of conditions generally prevalent in much of the U.S. Working in the region permitted us access to (i) a time-series of multi-scale and multi-temporal (including historical) satellite imagery and (ii) an established network of collaborating partners and agencies willing to share resources and to utilize developed techniques and model results. In addition, a unique parcel-level tax assessment database and linked parcel boundary maps exists for two counties in the Maryland portion of this region that made it possible to establish a historical cross-section time-series database of parcel level development decisions. Scenario analyses of future land use dynamics provided critical quantitative insight into the impact of alternative land management and policy decisions. These also have been specifically aimed at addressing growth control policies aimed at curbing exurban (sprawl) development. Our initial technical approach included three components: (i) spatial econometric modeling of the development decision, (ii) remote sensing of suburban change and residential land use density, including comparisons of past change from Landsat analyses and more traditional sources, and (iii) linkages between the two through variable initialization and supplementation of parcel level data. To these we added a fourth component, (iv) cellular automata modeling of urbanization, which proved to be a valuable addition to the project. This project has generated both remote sensing and spatially explicit socio-economic data to estimate and calibrate the parameters for two different types of land use change models and has

  5. Tumors in brown bullheads in the Chesapeake Bay watershed: analysis of survey data from 1992 through 2006.

    Science.gov (United States)

    Pikney, Alfred E; Harshbarger, John C; Rutter, Michael A

    2009-06-01

    Liver and skin tumor prevalences in brown bullheads Ameiurus nebulosus have been used in the North American Great Lakes to designate highly contaminated areas of concern and monitor their recovery. Here we interpret the results of six surveys conducted in the Chesapeake Bay watershed between 1992 and 2006, with data for 647 fish. The objective has been to develop an adequate database to critically evaluate the use of tumor prevalence as a habitat quality indicator within the watershed. Surveys featured randomized fish collection; recording of sex, length, weight, and age; and histopathology of all livers and all raised skin lesions. The Bayes information criterion was used to analyze all possible combinations of age, gender, length, and weight as covariates for logistic regression. Length and gender were the covariates that best described liver tumor prevalence. There were no covariates in the model for skin tumor prevalence. In some surveys, biomarkers, such as biliary polynuclear aromatic hydrocarbon (PAH)-like metabolites, hepatic cytochrome P450 activity, and hepatic DNA adducts, were used with sediment and tissue chemistry data to evaluate classes of chemicals as likely contributors to tumor prevalence. We highlight two surveys of the Anacostia River, Washington, D.C. (average = 55% liver tumors, 23% skin tumors), where sediment PAHs, biliary PAH-like metabolites, and hepatic DNA adducts were high, suggesting that PAHs play a major role. We show that logistic regression is an appropriate procedure for comparing "contaminated" versus "reference" locations, and we evaluate the utility of tumor surveys as an environmental indicator for the Chesapeake Bay watershed.

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  12. Wave spectra, meteorological, and other data from NOAA Ship FERREL and other platforms from the Chesapeake Bay from 1983-03-14 to 1983-11-22 (NCEI Accession 8500124)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Wave spectra, meteorological, and other data were collected from NOAA Ship FERREL and other platforms in the Chesapeake Bay. Data were collected by the National...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Science.gov (United States)

    Levine, Arlene S.

    2008-01-01

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

  3. Comparison of MSS and TM Data for Landcover Classification in the Chesapeake Bay Area: a Preliminary Report. [Taylor's Island, Maryland

    Science.gov (United States)

    Mulligan, P. J.; Gervin, J. C.; Lu, Y. C.

    1985-01-01

    An area bordering the Eastern Shore of the Chesapeake Bay was selected for study and classified using unsupervised techniques applied to LANDSAT-2 MSS data and several band combinations of LANDSAT-4 TM data. The accuracies of these Level I land cover classifications were verified using the Taylor's Island USGS 7.5 minute topographic map which was photointerpreted, digitized and rasterized. The the Taylor's Island map, comparing the MSS and TM three band (2 3 4) classifications, the increased resolution of TM produced a small improvement in overall accuracy of 1% correct due primarily to a small improvement, and 1% and 3%, in areas such as water and woodland. This was expected as the MSS data typically produce high accuracies for categories which cover large contiguous areas. However, in the categories covering smaller areas within the map there was generally an improvement of at least 10%. Classification of the important residential category improved 12%, and wetlands were mapped with 11% greater accuracy.

  4. Sources of suspended-sediment flux in streams of the chesapeake bay watershed: A regional application of the sparrow model

    Science.gov (United States)

    Brakebill, J.W.; Ator, S.W.; Schwarz, G.E.

    2010-01-01

    We describe the sources and transport of fluvial suspended sediment in nontidal streams of the Chesapeake Bay watershed and vicinity. We applied SPAtially Referenced Regressions on Watershed attributes, which spatially correlates estimated mean annual flux of suspended sediment in nontidal streams with sources of suspended sediment and transport factors. According to our model, urban development generates on average the greatest amount of suspended sediment per unit area (3,928 Mg/km2/year), although agriculture is much more widespread and is the greatest overall source of suspended sediment (57 Mg/km2/year). Factors affecting sediment transport from uplands to streams include mean basin slope, reservoirs, physiography, and soil permeability. On average, 59% of upland suspended sediment generated is temporarily stored along large rivers draining the Coastal Plain or in reservoirs throughout the watershed. Applying erosion and sediment controls from agriculture and urban development in areas of the northern Piedmont close to the upper Bay, where the combined effects of watershed characteristics on sediment transport have the greatest influence may be most helpful in mitigating sedimentation in the bay and its tributaries. Stream restoration efforts addressing floodplain and bank stabilization and incision may be more effective in smaller, headwater streams outside of the Coastal Plain. ?? 2010 American Water Resources Association. No claim to original U.S. government works.

  5. Metatranscriptomic analyses of plankton communities inhabiting surface and subpycnocline waters of the Chesapeake Bay during oxic-anoxic-oxic transitions.

    Science.gov (United States)

    Hewson, Ian; Eggleston, Erin M; Doherty, Mary; Lee, Dong Yoon; Owens, Michael; Shapleigh, James P; Cornwell, Jeffrey C; Crump, Byron C

    2014-01-01

    We used metatranscriptomics to study the gene transcription patterns of microbial plankton (0.2 to 64 μm) at a mesohaline station in the Chesapeake Bay under transitions from oxic to anoxic waters in spring and from anoxic to oxic waters in autumn. Samples were collected from surface (i.e., above pycnocline) waters (3 m) and from waters beneath the pycnocline (16 to 22 m) in both 2010 and 2011. Metatranscriptome profiles based on function and potential phylogeny were different between 2010 and 2011 and strongly variable in 2011. This difference in variability corresponded with a highly variable ratio of eukaryotic to bacterial sequences (0.3 to 5.5), reflecting transient algal blooms in 2011 that were absent in 2010. The similarity between metatranscriptomes changed at a lower rate during the transition from oxic to anoxic waters than after the return to oxic conditions. Transcripts related to photosynthesis and low-affinity cytochrome oxidases were significantly higher in shallow than in deep waters, while in deep water genes involved in anaerobic metabolism, particularly sulfate reduction, succinyl coenzyme A (succinyl-CoA)-to-propionyl-CoA conversion, and menaquinone synthesis, were enriched relative to in shallow waters. Expected transitions in metabolism between oxic and anoxic deep waters were reflected in elevated levels of anaerobic respiratory reductases and utilization of propenediol and acetoin. The percentage of archaeal transcripts increased in both years in late summer (from 0.1 to 4.4% of all transcripts in 2010 and from 0.1 to 6.2% in 2011). Denitrification-related genes were expressed in a predicted pattern during the oxic-anoxic transition. Overall, our data suggest that Chesapeake Bay microbial assemblages express gene suites differently in shallow and deep waters and that differences in deep waters reflect variable redox states.

  6. Chesapeake Bay Tidal Flooding Study. Appendix A. Problem Identification. Appendix B. Plan Formulation, Assessment and Evaluation. Appendix C. Recreation and Natural Resources.

    Science.gov (United States)

    1984-09-01

    MEMORIA is ayA FIUR A-3 POTOT AREA PLYAL Y’AGS 93 URCN SA ~ ~ 110r T6RV made to eliminate the Scott’s Creek area and make a tie-out at Glasgow and Godwin...or near prime recreation areas. Both Maryland and Virginia have on-going programs relative to this form of pollution. BAY BIOTA The stinging sea...and development for swimming. However, the large undeveloped areas and frontage on both the Atlantic Ocean and the Chesapeake Bay make them of prime

  7. Myxosporean plasmodial infection associated with ulcerative lesions in young-of-the-year Atlantic menhaden in a tributary of the Chesapeake Bay, and possible links to Kudoa clupeidae

    Science.gov (United States)

    Reimschuessel, R.; Gieseker, C.M.; Driscoll, C.; Baya, A.; Kane, A.S.; Blazer, V.S.; Evans, J.J.; Kent, M.L.; Moran, J.D.W.; Poynton, S.L.

    2003-01-01

    Ulcers in Atlantic menhaden Brevoortia tyrannus (Latrobe) (Clupeidae), observed along the USA east coast, have been attributed to diverse etiologies including bacterial, fungal and, recently, harmful algal blooms. To understand the early pathogenesis of these lesions, we examined juvenile Atlantic menhaden collected during their seasonal presence in Chesapeake Bay tributaries from April to October 1999 and from March to August 2000. We conducted histopathological examinations of young-of-the-year fish from the Pocomoke River tributary, which has a history of fish mortalities and high lesion prevalence. Kudoa clupeidae (Myxozoa: Myxosporea) spores were present in the muscles of fish collected in both years. Of the fish assessed by histology in April, 5 to 14% were infected, while in May 90 to 96% were infected. Infection rates remained high during the summer. Mature spores were primarily located within myomeres and caused little or no observable pathological changes. Ultrastructure showed spores with capsulogenic cells bearing filamentous projections, and a basal crescentic nucleus with mottled nucleoplasm containing cleaved, condensed chromatin. Also, a highly invasive plasmodial stage of a myxozoan was found in the lesions of juvenile Atlantic menhaden. The plasmodia were observed in fish collected between May and July, with the maximum occurrence in late June 1999 and late May 2000. Plasmodia penetrated and surrounded muscle bundles, causing grossly observable raised lesions in 73% of all fish infected with this invasive stage. Plasmodia were also detected in the visceral organs, branchial arches, and interocular muscles of some fish. Some of the invasive extrasporogonic plasmodial lesions were associated with ulcers and chronic inflammatory infiltrates. The plasmodial stage appeared to slough out of the tissue with subsequent evidence of wound healing. Ultrastructure showed plasmodia with an elaborate irregular surface, divided into distinct ectoplasm and

  8. Seasonal Phytoplankton Composition and Concentrations in the Lower Chesapeake Bay and Vicinity.

    Science.gov (United States)

    1984-03-31

    and Willoughby Bay collections. A more extensive list of cyanobacteria ( cyanophyta ) in the plankton were noted in the lower Bay and in the Bay plume...Dinophyceae (61), Haptophyceae (Prymnesio- phyceae) (6), Cyanobacteria (Cyanophyceae) (9), Euglenophyceae (6), Chlorophyceae (11), Cryptophyceae (4...into three size categories (ɛ, 3-5, and 6-10 um), they represent a mixture of mainly cyanobacteria (cyanophyceae) and nonflagellated chlorophytes. i

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

    Science.gov (United States)

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

    2003-01-01

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

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

    Science.gov (United States)

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

    2002-12-01

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

  11. Increased terrestrial to ocean sediment and carbon fluxes in the northern Chesapeake Bay associated with twentieth century land alteration

    Science.gov (United States)

    Saenger, C.; Cronin, T. M.; Willard, D.; Halka, J.; Kerhin, R.

    2008-01-01

    We calculated Chesapeake Bay (CB) sediment and carbon fluxes before and after major anthropogenic land clearance using robust monitoring, modeling and sedimentary data. Four distinct fluxes in the estuarine system were considered including (1) the flux of eroded material from the watershed to streams, (2) the flux of suspended sediment at river fall lines, (3) the burial flux in tributary sediments, and (4) the burial flux in main CB sediments. The sedimentary maximum in Ambrosia (ragweed) pollen marked peak land clearance (~1900 a.d.). Rivers feeding CB had a total organic carbon (TOC)/total suspended solids of 0.24??0.12, and we used this observation to calculate TOC fluxes from sediment fluxes. Sediment and carbon fluxes increased by 138-269% across all four regions after land clearance. Our results demonstrate that sediment delivery to CB is subject to significant lags and that excess post-land clearance sediment loads have not reached the ocean. Post-land clearance increases in erosional flux from watersheds, and burial in estuaries are important processes that must be considered to calculate accurate global sediment and carbon budgets. ?? 2008 Coastal and Estuarine Research Federation.

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

    Science.gov (United States)

    Lazarus, Rebecca; Rattner, Barnett A.; McGowan, Peter C.; Hale, Robert C.; Schultz, Sandra; Karouna, Natalie; Ottinger, Mary Ann

    2015-01-01

    The last large-scale ecotoxicological study of ospreys (Pandion haliaetus) in Chesapeake Bay was conducted in 2000-2001 and focused on U.S. EPA-designated Regions of Concern (ROCs; Baltimore Harbor/Patapsco, Anacostia/middle Potomac, and Elizabeth Rivers). In 2011-2012, ROCs were re-evaluated to determine spatial and temporal trends in productivity and contaminants. Concentrations of p,p'-DDE were low in eggs and below the threshold associated with eggshell thinning. Eggs from the Anacostia/middle Potomac Rivers had lower total PCB concentrations in 2011 than in 2000; however, concentrations remained unchanged in Baltimore Harbor. Polybrominated diphenyl ether flame retardants declined by 40%, and five alternative brominated flame retardants were detected at low levels. Osprey productivity was adequate to sustain local populations, and there was no relation between productivity and halogenated contaminants. Our findings document continued recovery of the osprey population, declining levels of many persistent halogenated compounds, and modest evidence of genetic damage in nestlings from industrialized regions.

  13. NASA-modified precipitation products to improve USEPA nonpoint source water quality modeling for the Chesapeake Bay.

    Science.gov (United States)

    Nigro, Joseph; Toll, David; Partington, Ed; Ni-Meister, Wenge; Lee, Shihyan; Gutierrez-Magness, Angelica; Engman, Ted; Arsenault, Kristi

    2010-01-01

    The USEPA has estimated that over 20,000 water bodies within the United States do not meet water quality standards. One of the regulations in the Clean Water Act of 1972 requires states to monitor the total maximum daily load, or the amount of pollution that can be carried by a water body before it is determined to be "polluted," for any watershed in the United States (Copeland, 2005). In response to this mandate, the USEPA developed Better Assessment Science Integrating Nonpoint Sources (BASINS) as a decision support tool for assessing pollution and to guide the decision-making process for improving water quality. One of the models in BASINS, the Hydrological Simulation Program-Fortran (HSPF), computes continuous streamflow rates and pollutant concentration at each basin outlet. By design, precipitation and other meteorological data from weather stations serve as standard model input. In practice, these stations may be unable to capture the spatial heterogeneity of precipitation events, especially if they are few and far between. An attempt was made to resolve this issue by substituting station data with NASA-modified/NOAA precipitation data. Using these data within HSPF, streamflow was calculated for seven watersheds in the Chesapeake Bay Basin during low flow periods, convective storm periods, and annual flows. In almost every case, the modeling performance of HSPF increased when using the NASA-modified precipitation data, resulting in better streamflow statistics and, potentially, in improved water quality assessment.

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

    Directory of Open Access Journals (Sweden)

    Peter J. Lavrentyev

    2015-05-01

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

  15. Remote sensing of submerged aquatic vegetation in lower Chesapeake Bay - A comparison of Landsat MSS to TM imagery

    Science.gov (United States)

    Ackleson, S. G.; Klemas, V.

    1987-01-01

    Landsat MSS and TM imagery, obtained simultaneously over Guinea Marsh, VA, as analyzed and compares for its ability to detect submerged aquatic vegetation (SAV). An unsupervised clustering algorithm was applied to each image, where the input classification parameters are defined as functions of apparent sensor noise. Class confidence and accuracy were computed for all water areas by comparing the classified images, pixel-by-pixel, to rasterized SAV distributions derived from color aerial photography. To illustrate the effect of water depth on classification error, areas of depth greater than 1.9 m were masked, and class confidence and accuracy recalculated. A single-scattering radiative-transfer model is used to illustrate how percent canopy cover and water depth affect the volume reflectance from a water column containing SAV. For a submerged canopy that is morphologically and optically similar to Zostera marina inhabiting Lower Chesapeake Bay, dense canopies may be isolated by masking optically deep water. For less dense canopies, the effect of increasing water depth is to increase the apparent percent crown cover, which may result in classification error.

  16. Mycobacterium pseudoshottsii sp. nov., a slowly growing chromogenic species isolated from Chesapeake Bay striped bass (Morone saxatilis)

    Science.gov (United States)

    Rhodes, M.W.; Kator, H.; McNabb, A.; Deshayes, C.; Reyrat, J.-M.; Brown-Elliott, B. A.; Wallace, R.; Trott, K.A.; Parker, J.M.; Lifland, B.; Osterhout, G.; Kaattari, I.; Reece, K.; Vogelbein, W.; Ottinger, C.A.

    2005-01-01

    A group of slowly growing photochromogenic mycobacteria was isolated from Chesapeake Bay striped bass (Morone saxatilis) during an epizootic of mycobacteriosis. Growth characteristics, acid-fastness and 16S rRNA gene sequencing results were consistent with those of the genus Mycobacterium. Biochemical reactions, growth characteristics and mycolic acid profiles (HPLC) resembled those of Mycobacterium shottsii, a non-pigmented mycobacterium also isolated during the same epizootic. Sequencing of the 16S rRNA genes, the gene encoding the exported repeated protein (erp) and the gene encoding the 65 kDa heat-shock protein (hsp65) and restriction enzyme analysis of the hsp65 gene demonstrated that this group of isolates is unique. Insertion sequences associated with Mycobacterium ulcerans, IS2404 and IS2606, were detected by PCR. These isolates could be differentiated from other slowly growing pigmented mycobacteria by their inability to grow at 37 ??C, production of niacin and urease, absence of nitrate reductase, negative Tween 80 hydrolysis and resistance to isoniazid (1 ??g ml-1), p-nitrobenzoic acid, thiacetazone and thiophene-2-carboxylic hydrazide. On the basis of this polyphasic study, it is proposed that these isolates represent a novel species, Mycobacterium pseudoshottsii sp. nov. The type strain, L15T, has been deposited in the American Type Culture Collection as ATCC BAA-883T and the National Collection of Type Cultures (UK) as NCTC 13318T. ?? 2005 IUMS.

  17. Carbonate system biogeochemistry in a subterranean estuary - Waquoit Bay, USA

    Science.gov (United States)

    Liu, Qian; Charette, Matthew A.; Breier, Crystaline F.; Henderson, Paul B.; McCorkle, Daniel C.; Martin, William; Dai, Minhan

    2017-04-01

    Quantifying carbon fluxes associated with submarine groundwater discharge (SGD) remains challenging due to the complex biogeochemistry of the carbonate system in the subterranean estuary (STE). Here we conducted time series measurements of total alkalinity (TAlk) and dissolved inorganic carbon (DIC) in a well-studied coastal aquifer (Waquoit Bay, Massachusetts, USA). Groundwater samples were collected monthly from May 2009 to June 2010 across the freshwater-saltwater mixing zone of the Waquoit Bay (WB) STE. The concentrations of both TAlk and DIC in zero-salinity groundwater were variable, but were lower than those in the bay water (S ∼ 28). DIC underwent slightly non-conservative mixing between low and intermediate salinities while there was an apparent additional DIC source at high salinity (>20) in all seasons. TAlk concentrations exhibited even stronger variations, with evidence of both production and consumption in high salinity zones, and consistent TAlk consumption at intermediate salinity in summer and fall (June-December, 2009). The increases in DIC and TAlk at high salinity were attributed to aerobic respiration and denitrification in WB sediments during bay water recharge of the STE. We infer that the loss of TAlk at intermediate salinity reflects H+ production as reduced compounds (e.g. Fe2+) are oxidized within the STE. In terms of impacts on surface water inorganic carbon budgets, the SGD-derived DIC flux was mainly controlled by seasonal changes in SGD while a combination of TAlk concentration variability and SGD drove the TAlk flux. SGD-derived DIC, aqueous CO2, and H+ fluxes to the bay were ∼40-50% higher in summer vs. in winter, a result of enhanced marine groundwater flux and significant TAlk removal (proton addition) during periods of high seawater intrusion. Furthermore, the SGD-derived DIC flux was consistently greater than TAlk flux regardless of season, indicating that SGD serves to reduce the CO2 buffering capacity of surface water. Our

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

    Science.gov (United States)

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

    2012-01-01

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

  19. Evolution of crystalline target rocks and impactites in the chesapeake bay impact structure, ICDP-USGS eyreville B core

    Science.gov (United States)

    Horton, J.W.; Kunk, M.J.; Belkin, H.E.; Aleinikoff, J.N.; Jackson, J.C.; Chou, I.-Ming

    2009-01-01

    The 1766-m-deep Eyreville B core from the late Eocene Chesapeake Bay impact structure includes, in ascending order, a lower basement-derived section of schist and pegmatitic granite with impact breccia dikes, polymict impact breccias, and cataclas tic gneiss blocks overlain by suevites and clast-rich impact melt rocks, sand with an amphibolite block and lithic boulders, and a 275-m-thick granite slab overlain by crater-fill sediments and postimpact strata. Graphite-rich cataclasite marks a detachment fault atop the lower basement-derived section. Overlying impactites consist mainly of basement-derived clasts and impact melt particles, and coastalplain sediment clasts are underrepresented. Shocked quartz is common, and coesite and reidite are confirmed by Raman spectra. Silicate glasses have textures indicating immiscible melts at quench, and they are partly altered to smectite. Chrome spinel, baddeleyite, and corundum in silicate glass indicate high-temperature crystallization under silica undersaturation. Clast-rich impact melt rocks contain ??- cristobalite and monoclinic tridymite. The impactites record an upward transition from slumped ground surge to melt-rich fallback from the ejecta plume. Basement-derived rocks include amphibolite-facies schists, greenschist(?)-facies quartz-feldspar gneiss blocks and subgreenschist-facies shale and siltstone clasts in polymict impact breccias, the amphibolite block, and the granite slab. The granite slab, underlying sand, and amphibolite block represent rock avalanches from inward collapse of unshocked bedrock around the transient crater rim. Gneissic and massive granites in the slab yield U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon dates of 615 ?? 7 Ma and 254 ?? 3 Ma, respectively. Postimpact heating was 7lt;~350 ??C in the lower basementderived section based on undisturbed 40Ar/ 39Ar plateau ages of muscovite and <~150

  20. Population ecology and shell chemistry of a phytal ostracode species (Loxoconcha matagordensis) in the Chesapeake Bay watershed

    Science.gov (United States)

    Vann, C.D.; Cronin, T. M.; Dwyer, G.S.

    2004-01-01

    Population ecology and shell chemistry were studied in the phytal ostracode Loxoconcha matagordensis (Swain 1955) collected from Zostera marina seagrass beds in the Chesapeake Bay to provide seasonal constraints on shell secretion time for paleothermometry. Population density and age structure were defined by two main breeding cycles that occurred between 01 to 15 June and 02 to 16 August 2001. The time interval between breeding cycles was ???2 months and total juvenile standing crop increased almost three-fold between the first and second breeding cycles. Dark brown over-wintered adults comprised the majority of the population between March and April 2001, while newly secreted translucent adults were predominant between June and September. Seasonal shell Mg/Ca and Sr/Ca ratios were positively correlated with water temperature at both sites, with the strongest correlations occurring between June and September from newly secreted shells at Dameron Marsh. Old, dark brown shells contained 10% to 23% and 1% to 6% less Mg/Ca and Sr/Ca, respectively, than new shells. Because a fossil assemblage of L. matagordensis will contain ???30% old shells (dark-brown), these results suggest that fossil Mg/Ca ratios yield an integrated late spring to summer temperature signal. Shell Mg/Ca and Sr/Ca ratios of specimens of L. matagordensis collected from living Zostera were positively correlated, suggesting that temperature may influence both elemental ratios. Mg/Ca and Sr/Ca ratios of fossil shells of the related species Loxoconcha sp. A obtained from four sediment cores were also studied and exhibited a weaker correlation between the two elemental ratios. ?? 2004 Elsevier B.V. All rights reserved.

  1. Supporting Coastal Management Decisions in the Face of Sea-Level Rise: Case Study for the Chesapeake Bay Region

    Science.gov (United States)

    Staudt, A. C.; Glick, P.; Clough, J. S.; Nunley, B.

    2008-12-01

    Sea-level rise needs to be a major consideration in regional coastal management and ecological restoration plans. The National Wildlife Federation has initiated a multi-pronged strategy for assisting decision makers at government agencies that manage near-shore ecosystems in several vulnerable coastal regions. Results from our work in the Chesapeake Bay region will be presented. This strategy involves: (1) Detailed modeling of how coastal habitats will migrate in response to a range of sea-level rise scenarios. For this work, we used the Sea Level Affecting Marshes Model (SLAMM), which simulates the dominant processes involved in wetland conversions and shoreline modifications during long-term sea-level rise and takes into consideration localized changes in land elevation due to geological and ecological factors. These model results provide specific information about the locations that are likely to experience shifts in coastal marshes, swamps, beaches, and other habitats due to sea-level rise at a scale that is relevant to regional decision making. (2) Extensive literature review and analysis of habitat, fish, and wildlife impacts potentially resulting from expected sea-level rise and other local climate changes. Synthesizing the available research is an important service for natural resource agencies that are only beginning to consider climate impacts on ecosystems and natural resources. (3) Analysis of government programs and policies relevant to coastal management and identification of opportunities to revise these policies in light of projected climate changes. An important aspect of this analysis is meeting with key decision makers at relevant state fish and wildlife agencies to better understand the factors that affect their abilities to effect policy changes. (4) Proactive campaign to share our results with diverse audiences. We have developed different research products, ranging from a technical report of the modeling results to short report briefs, to

  2. Gridded bathymetry of Kaneohe Bay, Windward Side Oahu, Main Hawaiian Islands, USA.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 4-m grid of bathymetric data of Kaneohe Bay, Windward Side Oahu, Main Hawaiian Islands, USA. These netCDF and ASCII grids include multibeam bathymetry from the Reson...

  3. Comparison of two regression-based approaches for determining nutrient and sediment fluxes and trends in the Chesapeake Bay watershed

    Science.gov (United States)

    Moyer, Douglas; Hirsch, Robert M.; Hyer, Kenneth

    2012-01-01

    Nutrient and sediment fluxes and changes in fluxes over time are key indicators that water resource managers can use to assess the progress being made in improving the structure and function of the Chesapeake Bay ecosystem. The U.S. Geological Survey collects annual nutrient (nitrogen and phosphorus) and sediment flux data and computes trends that describe the extent to which water-quality conditions are changing within the major Chesapeake Bay tributaries. Two regression-based approaches were compared for estimating annual nutrient and sediment fluxes and for characterizing how these annual fluxes are changing over time. The two regression models compared are the traditionally used ESTIMATOR and the newly developed Weighted Regression on Time, Discharge, and Season (WRTDS). The model comparison focused on answering three questions: (1) What are the differences between the functional form and construction of each model? (2) Which model produces estimates of flux with the greatest accuracy and least amount of bias? (3) How different would the historical estimates of annual flux be if WRTDS had been used instead of ESTIMATOR? One additional point of comparison between the two models is how each model determines trends in annual flux once the year-to-year variations in discharge have been determined. All comparisons were made using total nitrogen, nitrate, total phosphorus, orthophosphorus, and suspended-sediment concentration data collected at the nine U.S. Geological Survey River Input Monitoring stations located on the Susquehanna, Potomac, James, Rappahannock, Appomattox, Pamunkey, Mattaponi, Patuxent, and Choptank Rivers in the Chesapeake Bay watershed. Two model characteristics that uniquely distinguish ESTIMATOR and WRTDS are the fundamental model form and the determination of model coefficients. ESTIMATOR and WRTDS both predict water-quality constituent concentration by developing a linear relation between the natural logarithm of observed constituent

  4. Assessing the effectiveness of winter cover crop on nitrate reduction in two-paired sub-basins on the Coastal Plain of the Chesapeake Bay Watershed

    Science.gov (United States)

    Lee, S.; Yeo, I. Y.; Sadeghi, A. M.; Mccarty, G.; Hively, W. D.; Lang, M. W.

    2014-12-01

    Best management practices (BMPs) have been widely adopted to improve water quality throughout the Chesapeake Bay Watershed (CBW). Winter cover crops (WCC) use has been highlighted for the reduction of nitrate leaching over the fallow season. Although various WCC practices are currently conducted in local croplands, the water quality improvement benefits of WCC have not been studied thoroughly at the watershed scale. The objective of this study is to assess the long-term impacts of WCC on reducing nitrate loadings using a processed-based watershed model, Soil and Water Assessment Tool (SWAT). Remote sensing based estimates of WCC biomass will be used to calibrate plant growth processes of SWAT and its nutrient cycling. The study will be undertaken in two-paired agricultural watersheds in the Coastal Plain of CBW. Multiple WCC practice scenarios will be prepared to investigate how nitrate loading varies with crop species, planting dates, and implementation areas. The performance of WCC on two-paired watersheds will be compared in order to understand the effects of different watershed characteristics on nitrate uptake by crops. The results will demonstrate the nitrate reduction efficiency of different WCC practices and identify the targeting area for WCC implementation at the watershed scale. This study will not only integrate remote sensing data into the physically based model but also extend our understandings of WCC functions. This will provide key information for effective conservation decision making. Key words: Water quality, Chesapeake Bay Watershed, Winter Cover Crop, Soil and Water Assessment Tool (SWAT)

  5. Polar organic compounds in pore waters of the Chesapeake Bay impact structure, Eyreville core hole: Character of the dissolved organic carbon and comparison with drilling fluids

    Science.gov (United States)

    Rostad, C.E.; Sanford, W.E.

    2009-01-01

    Pore waters from the Chesapeake Bay impact structure cores recovered at Eyreville Farm, Northampton County, Virginia, were analyzed to characterize the dissolved organic carbon. After squeezing or centrifuging, a small volume of pore water, 100 ??L, was taken for analysis by electrospray ionization-mass spectrometry. Porewater samples were analyzed directly without filtration or fractionation, in positive and negative mode, for polar organic compounds. Spectra in both modes were dominated by low-molecular-weight ions. Negative mode had clusters of ions differing by -60 daltons, possibly due to increasing concentrations of inorganic salts. The numberaverage molecular weight and weight-average molecular weight values for the pore waters from the Chesapeake Bay impact structure are higher than those reported for other aquatic sources of natural dissolved organic carbon as determined by electrospray ionization-mass spectrometry. In order to address the question of whether drilling mud fluids may have contaminated the pore waters during sample collection, spectra from the pore waters were compared to spectra from drilling mud fluids. Ions indicative of drilling mud fluids were not found in spectra from the pore waters, indicating there was no detectable contamination, and highlighting the usefulness of this analytical technique for detecting potential contamination during sample collection. ?? 2009 The Geological Society of America.

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

    Data.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    Sverdrup, Leif J.

    1966-11-01

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

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

    Science.gov (United States)

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

  9. The Effects of Changes in Land Cover/Land Use on Nutrient Loadings to the Chesapeake Bay Estuary Using Forecasts of Future Urbanization

    Science.gov (United States)

    Prince, S.; Roberts, A. D.

    2006-12-01

    The effects of short-term and projected long-term changes in spatially explicit land cover/land use (LC/LU) on nutrient loadings (total nitrogen (TN) and total phosphorus (TP) in kg/ha/yr) were studied in the Chesapeake Bay watershed (164,000 km2) estuary. Version 3.0 of the USGS Chesapeake Bay's SPAtially Referenced Regressions on Watershed Attributes (SPARROW) model was implemented for the widely studied Patuxent River Basin in Maryland. Probabilities of LC change were estimated using projections of impervious surface locations at the LANDSAT (30m) scale and the Slope, Land use, Exclusion, Urban extent, Transportation, and Hillshade (SLEUTH) model for three development scenarios: current trends, smart growth, and ecologically sustainable to the Year 2030. Six Maryland Hydrologic Unit Code (HUC)-11 watersheds (three within and three outside of the basin) with verified (published) TN/TP nutrient loadings based on Year 2000 data from the Maryland Department of Natural Resources (DNR) were analyzed to see how they compared with the aggregated smaller catchments estimate of TN/TP that were contained within the larger boundaries of the HUC-11 watersheds and based on Year 2000 LC/LC and imperviousness data. The aggregated SPARROW TN always overpredicted the published values, whereas the SPARROW TP underpredicted the published DNR TP in three watersheds and overpredicted the DNR in the others. TN R2 = 0.90, whereas TP R2 = 0.69 in comparing DNR with SPARROW. Since the regression results just reported are only potential nutrient loadings for catchments independent of any other processes based on the model TN/TP general equations, when allowed to run in the true nonlinear structure of the SPARROW models that account for stream/catchment connectivity and water/land chemistry, even better nutrient estimates should able to be purported over larger watersheds throughout the Chesapeake Bay. In addition, TN/TP loadings from 85 of the smaller SPARROW reach catchments associated

  10. Declining nitrate-N yields in the Upper Potomac River Basin: What is really driving progress under the Chesapeake Bay restoration?

    Science.gov (United States)

    Eshleman, Keith N.; Sabo, Robert D.

    2016-12-01

    Reducing nutrient pollution of surface and coastal waters in the U.S. and elsewhere remains a major environmental and engineering challenge for the 21st century. In the case of the Chesapeake Bay restoration, we still lack scientific proof that watershed-based management actions have been effective at reducing nonpoint-source nutrient loads from the land to this estuary in accordance with restoration goals. While the conventional wisdom is that implementation of best management practices (BMP's) and wastewater treatment have turned the tide against nutrient pollution, we examined long-term (1986-present) nitrate-N trends in streams and major tributaries of the Upper Potomac River Basin (UPRB) and found that: 1) dramatic reductions in annual discharge-weighted mean nitrate-N concentrations and yields across the UPRB can be almost universally attributed to reductions in atmospheric N deposition as opposed to on-the-ground management actions such as implementation of BMP's; 2) observed water quality changes generally comport with a modified kinetic N saturation model (MKNSM); 3) the MKNSM can separate the nitrate-N yield that is responsive to atmospheric deposition from a "non-responsive" yield; and 4) N saturation from atmospheric N deposition appears to be an inherently reversible process across most of the landscape. These unanticipated region-wide water quality benefits can be attributed to NOx emission controls brought about by the 1990 Clean Air Act Amendments (and subsequent U.S. NOX control programs) and reflect a water quality "success story" in the Chesapeake Bay restoration.

  11. Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs

    Science.gov (United States)

    Focazio, Michael J.; Plummer, L. Neil; Bohlke, John K.; Busenberg, Eurybiades; Bachman, L. Joseph; Powars, David S.

    1998-01-01

    Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the Chesapeake Bay watershed. A simple reservoir model, published data, and analyses of spring water were used to estimate residence times and apparent ages of ground-water discharge. Ranges of aquifer hydraulic characteristics throughout the Bay watershed were derived from published literature and were used to estimate ground-water residence times on the basis of a simple reservoir model. Simple combinations of rock type and physiographic province were used to delineate hydrogeomorphic regions (HGMR?s) for the study area. The HGMR?s are used to facilitate organization and display of the data and analyses. Illustrations depicting the relation of aquifer characteristics and associated residence times as a continuum for each HGMR were developed. In this way, the natural variation of aquifer characteristics can be seen graphically by use of data from selected representative studies. Water samples collected in September and November 1996, from 46 springs throughout the watershed were analyzed for chlorofluorocarbons (CFC?s) to estimate the apparent age of ground water. For comparison purposes, apparent ages of water from springs were calculated assuming piston flow. Additi-onal data are given to estimate apparent ages assuming an exponential distribution of ages in spring discharge. Additionally, results from previous studies of CFC-dating of ground water from other springs and wells in the watershed were compiled. The CFC data, and the data on major ions, nutrients, and nitrogen isotopes in the water collected from the 46 springs are included in this report. The apparent ages of water

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

    Science.gov (United States)

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

    2003-01-01

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

  13. Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville-B core, Chesapeake Bay impact structure

    Science.gov (United States)

    Townsend, Gabrielle N.; Gibson, Roger L.; Horton, J. Wright; Reimold, Wolf Uwe; Schmitt, Ralf T.; Bartosova, Katerina

    2009-01-01

    The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ± fibrolite ± garnet ± tourmaline ± pyrite ± rutile ± pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite-K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase-quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ± biotite ± garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ± muscovite ± pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ± epidote ± amphibole. The lower basement-derived section and both megablocks exhibit similar middle- to upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafic source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites.

  14. The Eocene-Oligocene sedimentary record in the Chesapeake Bay impact structure: Implications for climate and sea-level changes on the western Atlantic margin

    Science.gov (United States)

    Schulte, P.; Wade, B.S.; Kontny, A.; ,

    2009-01-01

    A multidisciplinary investigation of the Eocene-Oligocene transition in the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville core from the Chesapeake Bay impact basin was conducted in order to document environmental changes and sequence stratigraphic setting. Planktonic foraminifera and calcareous nannofossil biostratigraphy indicate that the Eyreville core includes an expanded upper Eocene (Biozones E15 to E16 and NP19/20 to NP21, respectively) and a condensed Oligocene-Miocene (NP24-NN1) sedimentary sequence. The Eocene-Oligocene contact corresponds to a =3-Ma-long hiatus. Eocene- Oligocene sedimentation is dominated by great diversity and varying amounts of detrital and authigenic minerals. Four sedimentary intervals are identified by lithology and mineral content: (1) A 30-m-thick, smectite- and illite-rich interval directly overlies the Exmore Formation, suggesting long-term reworking of impact debris within the Chesapeake Bay impact structure. (2) Subsequently, an increase in kaolinite content suggests erosion from soils developed during late Eocene warm and humid climate in agreement with data derived from other Atlantic sites. However, the kaolinite increase may also be explained by change to a predominant sediment input from outside the Chesapeake Bay impact structure caused by progradation of more proximal facies belts during the highstand systems tract of the late Eocene sequence E10.Spectral analysis based on gamma-ray and magnetic susceptibility logs suggests infl uence of 1.2 Ma low-amplitude oscillation of the obliquity period during the late Eocene. (3) During the latest Eocene (Biozones NP21 and E16), several lithological contacts (clay to clayey silt) occur concomitant with a prominent change in the mineralogical composition with illite as a major component: This lithological change starts close to the Biozone NP19/20-NP21 boundary and may correspond to sequence boundary E10-E11 as observed in

  15. Polychlorinated biphenyl source attribution in Green Bay, Wisconsin, USA, using multivariate similarity among congener profiles in sediment samples.

    Science.gov (United States)

    Cacela, Dave; Beltman, Douglas J; Lipton, Joshua

    2002-08-01

    Polychlorinated biphenyl (PCB) congener concentrations measured in 1,189 sediment samples from Green Bay (MI/WI, USA), Lake Michigan (MI/WI, USA), and the Fox River (WI, USA) were analyzed statistically to evaluate whether PCB congener profiles in outer Green Bay are more similar to those observed in inner Green Bay or Lake Michigan. Similarities among PCB profiles were assessed with complementary multivariate analysis techniques: Principal component analysis (PCA), cluster analysis, and classification trees. The PCA indicated that profiles in outer Green Bay are distinct from those of inner Green Bay or Lake Michigan but are more similar to those of inner Green Bay. The outer bay profiles are dissimilar to profiles that would result from a simple process of mixing contaminated sediments from the inner bay with Lake Michigan sediments and, therefore, support the conclusion that contaminants in outer Green Bay come from discharges of the Fox River. Several classification trees based on small sets of congener proportions defined simple rules that consistently distinguished the regional profiles. Application of these rules to classify the outer bay samples suggests that the profiles of less than 7% of outer bay samples are similar to Lake Michigan profiles. These results are interpreted with respect to physical transport and chemical weathering processes that may account for the observed differences.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wade, Terry L. [Geochemical and Environmental Research Group, Texas A and M University, 833 Graham Road, College Station, TX 77845 (United States); Sweet, Stephen T. [Geochemical and Environmental Research Group, Texas A and M University, 833 Graham Road, College Station, TX 77845 (United States)], E-mail: sweet@gerg.tamu.edu; Klein, Andrew G. [Geography Department, Texas A and M University, 814B Eller O and M Building, College Station, TX 77843 (United States)

    2008-04-15

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

  17. Non-O1/non-O139 Vibrio cholerae carrying multiple virulence factors and V. cholerae O1 in the Chesapeake Bay, Maryland.

    Science.gov (United States)

    Ceccarelli, Daniela; Chen, Arlene; Hasan, Nur A; Rashed, Shah M; Huq, Anwar; Colwell, Rita R

    2015-03-01

    Non-O1/non-O139 Vibrio cholerae inhabits estuarine and coastal waters globally, but its clinical significance has not been sufficiently investigated, despite the fact that it has been associated with septicemia and gastroenteritis. The emergence of virulent non-O1/non-O139 V. cholerae is consistent with the recognition of new pathogenic variants worldwide. Oyster, sediment, and water samples were collected during a vibrio surveillance program carried out from 2009 to 2012 in the Chesapeake Bay, Maryland. V. cholerae O1 was detected by a direct fluorescent-antibody (DFA) assay but was not successfully cultured, whereas 395 isolates of non-O1/non-O139 V. cholerae were confirmed by multiplex PCR and serology. Only a few of the non-O1/non-O139 V. cholerae isolates were resistant to ampicillin and/or penicillin. Most of the isolates were sensitive to all antibiotics tested, and 77 to 90% carried the El Tor variant hemolysin gene hlyAET, the actin cross-linking repeats in toxin gene rtxA, the hemagglutinin protease gene hap, and the type 6 secretion system. About 19 to 21% of the isolates carried the neuraminidase-encoding gene nanH and/or the heat-stable toxin (NAG-ST), and only 5% contained a type 3 secretion system. None of the non-O1/non-O139 V. cholerae isolates contained Vibrio pathogenicity island-associated genes. However, ctxA, ace, or zot was present in nine isolates. Fifty-five different genotypes showed up to 12 virulence factors, independent of the source of isolation, and represent the first report of both antibiotic susceptibility and virulence associated with non-O1/non-O139 V. cholerae from the Chesapeake Bay. Since these results confirm the presence of potentially pathogenic non-O1/non-O139 V. cholerae, monitoring for total V. cholerae, regardless of serotype, should be done within the context of public health.

  18. Mercury in mussels of Bellingham Bay, Washington, (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Roesijadi, G.; Drum, A.S.; Bridge, J.R.

    1978-11-01

    Laboratory experiments demonstrated the existence of metallothionein-like, low molecular weight, mercury-binding proteins in the marine mussel Mytilus edulis. Relatively large quantities of mercury were associated with such proteins in gills and digestive gland, the organs of interest in the present study. /sup 14/C-incorporation indicated induction of the protein in gills, but not in digestive gland. Mercury in digestive gland may have bound to existing metal-binding proteins. Short-term incorporation of mercury occurred primarily in gills. The induction of mercury-binding proteins in gills may have facilitated detoxification of mercury at the site of uptake. Mercury in mussels of Bellingham Bay were shown to have decreased from 1970 to 1978, the collection date for the present study. Mercury levels were low but approximately three times higher than those from uncontaminated areas. Mercury associated with the mercury-binding protein of gills and digestive glands of Bellingham Bay mussels were low and reflected the concentrations measured in the whole tissues. However, the highest concentration of mercury was associated with the low molecular pool components, the identity of which is not presently known.

  19. 33 CFR 165.511 - Security Zone; Atlantic Ocean, Chesapeake & Delaware Canal, Delaware Bay, Delaware River and its...

    Science.gov (United States)

    2010-07-01

    ... escorted passenger vessels in the Captain of the Port, Delaware Bay zone as defined in 33 CFR 3.25-05. (b... vessel in order to ensure safe passage in accordance with the Navigation Rules as seen in 33 CFR...

  20. A chemostratigraphic method to determine the end of impact-related sedimentation at marine-target impact craters (Chesapeake Bay, Lockne, Tvären)

    Science.gov (United States)

    Ormö, Jens; Hill, Andrew C.; Self-Trail, Jean M.

    2010-01-01

    To better understand the impact cratering process and its environmental consequences at the local to global scale, it is important to know when in the geological record of an impact crater the impact-related processes cease. In many instances, this occurs with the end of early crater modification, leaving an obvious sedimentological boundary between impactites and secular sediments. However, in marine-target craters the transition from early crater collapse (i.e., water resurge) to postimpact sedimentation can appear gradual. With the a priori assumption that the reworked target materials of the resurge deposits have a different chemical composition to the secular sediments we use chemostratigraphy (δ13Ccarb, %Corg, major elements) of sediments from the Chesapeake Bay, Lockne, and Tvären craters, to define this boundary. We show that the end of impact-related sedimentation in these cases is fairly rapid, and does not necessarily coincide with a visual boundary (e.g., grain size shift). Therefore, in some cases, the boundary is more precisely determined by chemostratigraphy, especially carbonate carbon isotope variations, rather than by visual inspection. It is also shown how chemostratigraphy can confirm the age of marine-target craters that were previously determined by biostratigraphy; by comparing postimpact carbon isotope trends with established regional trends.

  1. The Chesapeake: A Boating Guide to Weather. Educational Series Number 25.

    Science.gov (United States)

    Lucy, Jon; And Others

    The purpose of this publication is to promote a better understanding of how basic weather features develop on Chesapeake Bay and enable boaters to enjoy the Bay's unique waterways. Sections include: (1) Chesapeake Bay climate; (2) general weather features; (3) seasonal trends; (4) sources of weather information and forecasts; (5) weather service…

  2. 77 FR 2317 - Captain John Smith Chesapeake National Historic Trail Advisory Council

    Science.gov (United States)

    2012-01-17

    ... National Park Service Captain John Smith Chesapeake National Historic Trail Advisory Council AGENCY... Captain John Smith Chesapeake National Historic Trail will hold a meeting via conference call. Designated... voyages of Captain John Smith to chart the land and waterways of the Chesapeake Bay. This meeting...

  3. Trends in nutrients and suspended solids at the Fall Line of five tributaries to the Chesapeake Bay in Virginia, July 1988 through June 1995

    Science.gov (United States)

    Bell, C.F.; Belval, D.L.; Campbell, J.P.

    1996-01-01

    Water-quality samples were collected at the Fall Line of five tributaries to the Chesapeake Bay in Virginia during a 6- to 7-year period. The water-quality data were used to estimate loads of nutrients and suspended solids from these tributaries to the non-tidal part of Chesapeake Bay Basin and to identify trends in water quality. Knowledge of trends in water quality is required to assess the effectiveness of nutrient manage- ment strategies in the five basins. Multivariate log-linear regression and the seasonal Kendall test were used to estimate flow-adjusted trends in constituent concentration and load. Results of multivariate log-linear regression indicated a greater number of statistically significant trends than the seasonal Kendall test; how-ever, when both methods indicated a significant trend, both agreed on the direction of the trend. Interpre- tation of the trend estimates for this report was based on results of the parametric regression method. No significant trends in total nitrogen concentration were detected at the James River monitoring station from July 1988 through June 1995, though total Kjeldahl nitrogen concen- tration decreased slightly in base-flow samples. Total phosphorus concentration decreased about 29 percent at this station during the sampling period. Most of the decrease can be attributed to reductions in point-source phosphorus loads in 1988 and 1989, especially the phosphate detergent ban of 1988. No significant trends in total suspended solids were observed at the James River monitoring station, and no trends in runoff- derived constituents were interpreted for this river. Significant decreases were detected in concentrations of total nitrogen, total Kjeldahl nitrogen, dissolved nitrite-plus-nitrate nitrogen, and total suspended solids at the Rappahannock River monitoring station between July 1988 and June 1995. A similar downward trend in total phosphorus concentration was significant at the 90-percent confidence level, but not the

  4. Geologic columns for the ICDP-USGS Eyreville A and C cores, Chesapeake Bay impact structure: Postimpact sediments, 444 to 0 m depth

    Science.gov (United States)

    Edwards, L.E.; Powars, D.S.; Browning, J.V.; McLaughlin, P.P.; Miller, K.G.; ,; Kulpecz, A.A.; Elbra, T.

    2009-01-01

    A 443.9-m-thick, virtually undisturbed section of postimpact deposits in the Chesapeake Bay impact structure was recovered in the Eyreville A and C cores, Northampton County, Virginia, within the "moat" of the structure's central crater. Recovered sediments are mainly fine-grained marine siliciclastics, with the exception of Pleistocene sand, clay, and gravel. The lowest postimpact unit is the upper Eocene Chickahominy Formation (443.9-350.1 m). At 93.8 m, this is the maximum thickness yet recovered for deposits that represent the return to "normal marine" sedimentation. The Drummonds Corner beds (informal) and the Old Church Formation are thin Oligocene units present between 350.1 and 344.7 m. Above the Oligocene, there is a more typical Virginia coastal plain succession. The Calvert Formation (344.7-225.4 m) includes a thin lower Miocene part overlain by a much thicker middle Miocene part. From 225.4 to 206.0 m, sediments of the middle Miocene Choptank Formation, rarely reported in the Virginia coastal plain, are present. The thick upper Miocene St. Marys and Eastover Formations (206.0-57.8 m) appear to represent a more complete succession than in the type localities. Correlation with the nearby Kiptopeke core indicates that two Pliocene units are present: Yorktown (57.8-32.2 m) and Chowan River Formations (32.2-18.3 m). Sediments at the top of the section represent an upper Pleistocene channel-fill and are assigned to the Butlers Bluff and Occohannock Members of the Nassawadox Formation (18.3-0.6 m). ?? 2009 The Geological Society of America.

  5. Geologic columns for the ICDP-USGS Eyreville A and B cores, Chesapeake Bay impact structure: Sediment-clast breccias, 1096 to 444 m depth

    Science.gov (United States)

    Edwards, L.E.; Powars, D.S.; Gohn, G.S.; Dypvik, H.

    2009-01-01

    The Eyreville A and B cores, recovered from the "moat" of the Chesapeake Bay impact structure, provide a thick section of sediment-clast breccias and minor stratified sediments from 1095.74 to 443.90 m. This paper discusses the components of these breccias, presents a geologic column and descriptive lithologic framework for them, and formalizes the Exmore Formation. From 1095.74 to ??867 m, the cores consist of nonmarine sediment boulders and sand (rare blocks up to 15.3 m intersected diameter). A sharp contact in both cores at ??867 m marks the lowest clayey, silty, glauconitic quartz sand that constitutes the base of the Exmore Formation and its lower diamicton member. Here, material derived from the upper sediment target layers, as well as some impact ejecta, occurs. The block-dominated member of the Exmore Formation, from ??855-618.23 m, consists of nonmarine sediment blocks and boulders (up to 45.5 m) that are juxtaposed complexly. Blocks of oxidized clay are an important component. Above 618.23 m, which is the base of the informal upper diamicton member of the Exmore Formation, the glauconitic matrix is a consistent component in diamicton layers between nonmarine sediment clasts that decrease in size upward in the section. Crystalline-rock clasts are not randomly distributed but rather form local concentrations. The upper part of the Exmore Formation consists of crudely fining-upward sandy packages capped by laminated silt and clay. The overlap interval of Eyreville A and B (940-??760 m) allows recognition of local similarities and differences in the breccias. ?? 2009 The Geological Society of America.

  6. Comparison of clast frequency and size in the resurge deposits at the Chesapeake Bay impact structure (Eyreville A and Langley cores): Clues to the resurge process

    Science.gov (United States)

    Ormo, J.; Sturkell, E.; Horton, J.W.; Powars, D.S.; Edwards, L.E.

    2009-01-01

    Collapse and inward slumping of unconsolidated sedimentary strata expanded the Chesapeake Bay impact structure far beyond its central basement crater. During crater collapse, sediment-loaded water surged back to fill the crater. Here, we analyze clast frequency and granulometry of these resurge deposits in one core hole from the outermost part of the collapsed zone (i.e., Langley) as well as a core hole from the moat of the basement crater (i.e., Eyreville A). Comparisons of clast provenance and flow dynamics show that at both locations, there is a clear change in clast frequency and size between a lower unit, which we interpret to be dominated by slumped material, and an upper, water-transported unit, i.e., resurge deposit. The contribution of material to the resurge deposit was primarily controlled by stripping and erosion. This includes entrainment of fallback ejecta and sediments eroded from the surrounding seafloor, found to be dominant at Langley, and slumped material that covered the annular trough and basement crater, found to be dominant at Eyreville. Eyreville shows a higher content of crystalline clasts than Langley. There is equivocal evidence for an anti-resurge from a collapsing central water plume or, alternatively, a second resurge pulse, as well as a transition into oscillating resurge. The resurge material shows more of a debris-flow-like transport compared to resurge deposits at some other marine target craters, where the ratio of sediment to water has been relatively low. This result is likely a consequence of the combination of easily disaggregated host sediments and a relatively shallow target water depth. ?? 2009 The Geological Society of America.

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

    Science.gov (United States)

    Drake, Bert G

    2014-11-01

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

  8. Drivers of phytoplankton dynamics in old Tampa Bay, FL (USA), a subestuary lagging in ecosystem recovery

    Science.gov (United States)

    Corcoran, Alina A.; Wolny, Jennifer; Leone, Erin; Ivey, James; Murasko, Susan

    2017-02-01

    In the past four decades, consistent and coordinated management actions led to the recovery of Tampa Bay, FL (USA) - an estuary that was declared dead in the 1970s. An exception to this success story is Old Tampa Bay, the northernmost subestuary of the system. Compared to the other bay segments, Old Tampa Bay is characterized by poorer water quality and spring and summer blooms of cyanobacteria, picoplankton, diatoms, and the saxitoxin-producing dinoflagellate Pyrodinium bahamense. Together, these blooms contribute to light attenuation and lagging recovery of seagrass beds. Yet, studies of phytoplankton dynamics within Old Tampa Bay have been limited - both in number and in their spatiotemporal resolution. In this study, we used field sampling and continuous monitoring to (1) characterize temporal and spatial variability in phytoplankton biomass and community composition and (2) identify key drivers of the different phytoplankton blooms in Old Tampa Bay. Overall, temporal variability in phytoplankton biomass (using chlorophyll a as a proxy) and community composition surpassed spatial variability of these parameters. We found a base community of small diatoms and flagellates, as well as certain dinoflagellates, that persisted year round in the system. Seasonally, freshwater runoff stimulated phytoplankton growth, specifically that of chlorophytes, cyanobacteria and other dinoflagellates - consistent with predictions based on ecological theory. On shorter time scales, salinity, visibility, and freshwater inflows were important predictors of phytoplankton biomass. With respect to P. bahamense, environmental drivers including salinity, temperature and dissolved nutrient concentrations explained ∼24% of the variability in cell abundance, indicating missing explanatory parameters in our study for this taxon, such as cyst density and location of cyst beds. Spatially, we found differences in community trajectories across north-south and west-east gradients, with the

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

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2016-01-13

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

  12. Enhanced dry deposition of nitrogen pollution near coastlines: A case study covering the Chesapeake Bay estuary and Atlantic Ocean coastline

    Science.gov (United States)

    Loughner, Christopher P.; Tzortziou, Maria; Shroder, Shulamit; Pickering, Kenneth E.

    2016-12-01

    Atmospheric deposition of nitrogen pollution is one of the major sources of nitrogen to many terrestrial and aquatic ecosystems, worldwide. This modeling study suggests that coastlines frequently experience disproportionally high dry deposition of reactive nitrogen. High concentrations of air pollution from coastal cities often accumulate over adjacent estuaries and coastal waters due to low dry deposition rates over the water and a shallow marine boundary layer trapping marine emissions. As high concentrations of pollutants over the water are transported inland, enhanced dry deposition occurs onshore along the coastlines. Large spatial gradients in air pollutants and deposition totals are simulated along the coastline with decreasing concentrations/deposition as the distance from the water increases. As pollutants are transported onshore, air pollution mixing ratios near the surface decrease due to removal by dry deposition, vertical dilution due to deeper mixing layer heights, and decrease in friction velocity as a function of distance inland from the coastline. Ammonium nitrate formation near agricultural ammonia sources, sodium nitrate formation near coastal areas with atmospheric sea-salt loadings, and particulate growth via water uptake also contribute to large nitrate dry deposition totals at the coastline. Gradients in dry N deposition are evident over a monthly time scale and are enhanced during sea and bay breeze events. Current existing N-deposition monitoring networks do not capture the large spatial gradients of ammonium, nitrate, and nitric acid concentrations near coastlines predicted by the model due to the coarse spatial density distribution of monitoring sites.

  13. Distribution, Origin, and Realtions to Flow of Salty Ground Water Along the Western Margin of the Chesapeake Bay Impact Structure in Eastern Virginia

    Science.gov (United States)

    McFarland, R.; Bruce, S.

    2002-05-01

    The Chesapeake Bay impact structure closely coincides with parts of some aquifers in eastern Virginia that contain saltwater as much as 30 miles landward of the coast. The impact structure has thereby been inferred to play some role in controlling the presence of this "inland saltwater wedge", which formed under unstressed conditions prior to present-day ground-water withdrawals. That the impact severely disrupted the previously stratified sediments casts doubt on conceptualizations of a regionally contiguous, vertically layered system of aquifers and confining units. In addition, large and increasing ground-water withdrawals have resulted in continuing water-level declines and altered flow directions that create the potential for saltwater intrusion. Hence, the origin and emplacement of the saltwater must be known to predict its reaction to stresses being placed upon the flow system. Specific conductances and concentrations of chloride in ground water along the western margin of the impact structure reflect a transitional interface between freshwater to the west and seawater to the east that coincides aerially with the margin of the impact structure. Ratios of bromide to chloride and chlorine-36 to total chloride, and of stable hydrogen and oxygen isotopes, indicate chloride to have originated primarily from mixing of freshwater and seawater across the interface. In addition, deep ground water east of the interface having specific conductances which exceed that of seawater likely resulted from partial evaporation of seawater, either (1) in restricted coastal environments under arid conditions, (2) by rapid vaporization caused by the impact event, and (or) (3) by residual heat and associated hydrothermal activity following the impact. Mixing of freshwater and seawater has been theorized to take place in a "differential flushing" manner that left residual seawater to form the saltwater wedge. Seawater emplaced during inundation of the land surface persisted around

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

    Science.gov (United States)

    Lee, Sangchul; Yeo, In-Young; Sadeghi, Ali M; McCarty, Gregory W; Hively, W Dean; Lang, Megan W

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Sangchul Lee

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

  16. An Application of the Mesh Generation and Refinement Tool to Mobile Bay, Alabama, USA

    Science.gov (United States)

    Aziz, Wali; Alarcon, Vladimir J.; McAnally, William; Martin, James; Cartwright, John

    2009-08-01

    A grid generation tool, called the Mesh Generation and Refinement Tool (MGRT), has been developed using Qt4. Qt4 is a comprehensive C++ application framework which includes GUI and container class-libraries and tools for cross-platform development. MGRT is capable of using several types of algorithms for grid generation. This paper presents an application of the MGRT grid generation tool for creating an unstructured grid of Mobile Bay (Alabama, USA) that will be used for hydrodynamics modeling. The algorithm used in this particular application is the Advancing-Front/Local-Reconnection (AFLR) [1] [2]. This research shows results of grids created with MGRT and compares them to grids (for the same geographical container) created using other grid generation tools. The superior quality of the grids generated by MGRT is shown.

  17. Coupled Wave Energy and Erosion Dynamics along a Salt Marsh Boundary, Hog Island Bay, Virginia, USA

    Directory of Open Access Journals (Sweden)

    Anthony M. Priestas

    2015-09-01

    Full Text Available The relationship between lateral erosion of salt marshes and wind waves is studied in Hog Island Bay, Virginia USA, with high-resolution field measurements and aerial photographs. Marsh retreat is compared to wave climate calculated in the bay using the spectral wave-model Simulating Waves Nearshore (SWAN. We confirm the existence of a linear relationship between long-term salt marsh erosion and wave energy, and show that wave power can serve as a good proxy for average salt-marsh erosion rates. At each site, erosion rates are consistent across several temporal scales, ranging from months to decades, and are strongly related to wave power. On the contrary, erosion rates vary in space and weakly depend on the spatial distribution of wave energy. We ascribe this variability to spatial variations in geotechnical, biological, and morphological marsh attributes. Our detailed field measurements indicate that at a small spatial scale (tens of meters, a positive feedback between salt marsh geometry and wave action causes erosion rates to increase with boundary sinuosity. However, at the scale of the entire marsh boundary (hundreds of meters, this relationship is reversed: those sites that are more rapidly eroding have a marsh boundary which is significantly smoother than the marsh boundary of sheltered and slowly eroding marshes.

  18. Concurrent exposure of bottlenose dolphins (Tursiops truncatus to multiple algal toxins in Sarasota Bay, Florida, USA.

    Directory of Open Access Journals (Sweden)

    Michael J Twiner

    Full Text Available Sentinel species such as bottlenose dolphins (Tursiops truncatus can be impacted by large-scale mortality events due to exposure to marine algal toxins. In the Sarasota Bay region (Gulf of Mexico, Florida, USA, the bottlenose dolphin population is frequently exposed to harmful algal blooms (HABs of Karenia brevis and the neurotoxic brevetoxins (PbTx; BTX produced by this dinoflagellate. Live dolphins sampled during capture-release health assessments performed in this region tested positive for two HAB toxins; brevetoxin and domoic acid (DA. Over a ten-year study period (2000-2009 we have determined that bottlenose dolphins are exposed to brevetoxin and/or DA on a nearly annual basis (i.e., DA: 2004, 2005, 2006, 2008, 2009; brevetoxin: 2000, 2004, 2005, 2008, 2009 with 36% of all animals testing positive for brevetoxin (n = 118 and 53% positive for DA (n = 83 with several individuals (14% testing positive for both neurotoxins in at least one tissue/fluid. To date there have been no previously published reports of DA in southwestern Florida marine mammals, however the May 2008 health assessment coincided with a Pseudo-nitzschia pseudodelicatissima bloom that was the likely source of DA observed in seawater and live dolphin samples. Concurrently, both DA and brevetoxin were observed in common prey fish. Although no Pseudo-nitzschia bloom was identified the following year, DA was identified in seawater, fish, sediment, snails, and dolphins. DA concentrations in feces were positively correlated with hematologic parameters including an increase in total white blood cell (p = 0.001 and eosinophil (p<0.001 counts. Our findings demonstrate that dolphins within Sarasota Bay are commonly exposed to two algal toxins, and provide the impetus to further explore the potential long-term impacts on bottlenose dolphin health.

  19. The Neoglacial landscape and human history of Glacier Bay, Glacier Bay National Park and Preserve, southeast Alaska, USA

    Science.gov (United States)

    Connor, C.; Streveler, G.; Post, A.; Monteith, D.; Howell, W.

    2009-01-01

    The Neoglacial landscape of the Huna Tlingit homeland in Glacier Bay is recreated through new interpretations of the lower Bay's fjordal geomorphology, late Quaternary geology and its ethnographic landscape. Geological interpretation is enhanced by 38 radiocarbon dates compiled from published and unpublished sources, as well as 15 newly dated samples. Neoglacial changes in ice positions, outwash and lake extents are reconstructed for c. 5500?????"200 cal. yr ago, and portrayed as a set of three landscapes at 1600?????"1000, 500?????"300 and 300?????"200 cal. yr ago. This history reveals episodic ice advance towards the Bay mouth, transforming it from a fjordal seascape into a terrestrial environment dominated by glacier outwash sediments and ice-marginal lake features. This extensive outwash plain was building in lower Glacier Bay by at least 1600 cal. yr ago, and had filled the lower bay by 500 cal. yr ago. The geologic landscape evokes the human-described landscape found in the ethnographic literature. Neoglacial climate and landscape dynamism created difficult but endurable environmental conditions for the Huna Tlingit people living there. Choosing to cope with environmental hardship was perhaps preferable to the more severely deteriorating conditions outside of the Bay as well as conflicts with competing groups. The central portion of the outwash plain persisted until it was overridden by ice moving into Icy Strait between AD 1724?????"1794. This final ice advance was very abrupt after a prolonged still-stand, evicting the Huna Tlingit from their Glacier Bay homeland. ?? 2009 SAGE Publications.

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

    Science.gov (United States)

    Moyer, Douglas; Bennett, Mark

    2007-01-01

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

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

    Science.gov (United States)

    Fischer, Andrew; MorenoMadrinan, Max J.

    2012-01-01

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

  2. USA

    DEFF Research Database (Denmark)

    Nedergaard, Peter

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

  3. Albino mutation rates in red mangroves (Rhizophora mangle L.) as a bioassay of contamination history in Tampa Bay, Florida, USA

    Science.gov (United States)

    Proffitt, C.E.; Travis, S.E.

    2005-01-01

    We assessed the sensitivity of a viviparous estuarine tree species, Rhizophora mangle, to historic sublethal mutagenic stress across a fine spatial scale by comparing the frequency of trees producing albino propagules in historically contaminated (n=4) and uncontaminated (n=11) forests in Tampa Bay, Florida, USA. Data from uncontaminated forests were used to provide estimates of background mutation rates. We also determined whether other fitness parameters were negatively correlated with mutagenic stress (e.g., degree of outcrossing and numbers of reproducing trees km-1). Contaminated sites in Tampa Bay had significantly higher frequencies of trees that were heterozygous for albinism per 1000 total reproducing trees (FHT) than uncontaminated forests (mean ?? SE: 11.4 ?? 4.3 vs 4.3 ?? 0.73, P 25 yrs of subsequent recruitment and tree replacement may have allowed an initial elevation in the FHT to decay. Patterns of FHT were not explained by distance from the bay mouth or the degree of urbanization. However, there was a significant positive relationship between tree size and FHT (r=0.83, Pstress. No other fitness parameters correlated with FHT. There was a difference in FHT between two latitudes, as determined by comparing Tampa Bay with literature values for Puerto Rico. The sensitivity of this bioassay for the effects of mutagens will facilitate future monitoring of contamination events and comparisons of bay-wide recovery in future decades. Development of a database of FHT values for a range of subtropical and tropical estuaries is underway that will provide a baseline against which to compare mutational consequences of global change. ?? 2005, The Society of Wetland Scientists.

  4. Reproductive outcome and survival of common bottlenose dolphins sampled in Barataria Bay, Louisiana, USA, following the Deepwater Horizon oil spill.

    Science.gov (United States)

    Lane, Suzanne M; Smith, Cynthia R; Mitchell, Jason; Balmer, Brian C; Barry, Kevin P; McDonald, Trent; Mori, Chiharu S; Rosel, Patricia E; Rowles, Teresa K; Speakman, Todd R; Townsend, Forrest I; Tumlin, Mandy C; Wells, Randall S; Zolman, Eric S; Schwacke, Lori H

    2015-11-01

    Common bottlenose dolphins (Tursiops truncatus) inhabit bays, sounds and estuaries across the Gulf of Mexico. Following the Deepwater Horizon oil spill, studies were initiated to assess potential effects on these ecologically important apex predators. A previous study reported disease conditions, including lung disease and impaired stress response, for 32 dolphins that were temporarily captured and given health assessments in Barataria Bay, Louisiana, USA. Ten of the sampled dolphins were determined to be pregnant, with expected due dates the following spring or summer. Here, we report findings after 47 months of follow-up monitoring of those sampled dolphins. Only 20% (95% CI: 2.50-55.6%) of the pregnant dolphins produced viable calves, as compared with a previously reported pregnancy success rate of 83% in a reference population. Fifty-seven per cent of pregnant females that did not successfully produce a calf had been previously diagnosed with moderate-severe lung disease. In addition, the estimated annual survival rate of the sampled cohort was low (86.8%, 95% CI: 80.0-92.7%) as compared with survival rates of 95.1% and 96.2% from two other previously studied bottlenose dolphin populations. Our findings confirm low reproductive success and high mortality in dolphins from a heavily oiled estuary when compared with other populations. Follow-up studies are needed to better understand the potential recovery of dolphins in Barataria Bay and, by extension, other Gulf coastal regions impacted by the spill.

  5. The areal extent of brown shrimp habitat suitability in Mobile Bay, Alabama, USA: Targeting vegetated habitat restoration

    Science.gov (United States)

    Smith, L.M.; Nestlerode, J.A.; Harwell, L.C.; Bourgeois, P.

    2010-01-01

    The availability of wetlands and shallow water habitats significantly influences Gulf of Mexico (GOM) penaeid shrimp fishery productivity. However, the GOM region has the highest rate of wetland loss in the USA. Protection and management of these vital GOM habitats are critical to sustainable shrimp fisheries. Brown shrimp (Farfantepenaeus aztecus) are a major component of GOM fisheries. We present an approach for estimating the areal extent of suitable habitat for post-larval and juvenile brown shrimp in Mobile Bay, Alabama, using an existing habitat suitability index model for the northern GOM calculated from probabilistic survey of water quality and sediment data, land cover data, and submerged aquatic vegetation coverages. This estuarine scale approach is intended to support targeted protection and restoration of these habitats. These analyses indicate that approximately 60% of the area of Mobile Bay is categorized as suitable to near optimal for post-larval and juvenile shrimp and 38% of the area is marginally to minimally suitable. We identify potential units within Mobile Bay for targeted restoration to improve habitat suitability. ?? 2010 Springer Science+Business Media B.V.

  6. Fresh Water Inflow and Oyster Productivity in Apalachicola Bay, FL (USA)

    Science.gov (United States)

    Apalachicola Bay lies at the mouth of the Apalachicola River, where seasonally variable freshwater inflows and shifting winds support an unusually productive and commercially important oyster fishery. While there is concern that upstream water withdrawals may impact the fishery,...

  7. Bacterial community biodiversity in estuaries and its controlling factors:a case study in Chesapeake Bay%河口细菌群落多样性及其控制因素:以切萨皮克湾为例

    Institute of Scientific and Technical Information of China (English)

    阚金军; 孙军

    2011-01-01

    Estuaries are among the most productive and dynamic aquatic ecosystems on earth, due to the mixing of fresh and salt waters and significant recycling of nutrients and organic matters. Sitting in a transitional zone, bacterial communities in an estuary typically harbor representatives of both freshwater and marine groups: Alphaproteobacteria, Betaproteobacteria, Gatnmaproteobacteria, Cyanobacteria (Synechococcus), Bacteroidetes, Actinobacteria, and Verrucomicrobia. In addition, estuaries such as Chesapeake Bay also contain their own unique bacterial signatures including the SARI 1 group, Roseobacter, SAR86, and Actinobacteria subclades, suggesting the ecological adaptation of organisms endemic to the Bay or perhaps, to large temperate estuaries in general. Relative to spatial variations, remarkable seasonal shifts and recurring annual patterns were identified in Chesapeake Bay bacterial communities. Besides water residence time and bacterial growth rate, many other factors are potential driving forces for the microbial diversity and bacterial population dynamics we observed. Temporal variations in bacterial communities were best explained by change in chlorophyll a (Chi a) and water temperature, while other factors such as dissolved oxygen, ammonia, nitrite and nitrate, and viral abundance also appeared to contribute to seasonal succession. Recently, the applications of community-based genomics and postgenomics (transcriptomics and proteomics) have allowed us to study the comprehensive gene diversity and gene expression directly from natural microbial communities. We predict that further studies and analyses of these genes and proteins will deliver new discoveries regarding the composition and function of microbial communities in aquatic environments.%咸淡水的混合和重要营养盐与有机物的再循环,使得河口成为地球上生产力较高而动态变化明显的水生生态系统.一个典型的河口区断面中,细菌群落包含了一些从

  8. Water Quality Assessment of DoD Installations/Facilities in the Chesapeake Bay Region. Phase 3. Volume 2. Overall Approach, Findings and Recommendations.

    Science.gov (United States)

    1987-11-01

    to quantify, where possible, the impacts of an installation on water quality in terms of: 1) conventional poilu - tants (nutrient, coliform and BOD...wildlife are the more visible manifestations of ecosystems in the estuary. Actually, there are many complex physico -chemical-biological interactions...that environmental stresses and rep’,- , in some areas of the Bay than in ot her.. 1l I, development of a segmentation scheme of the e ,ar. physico

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

    NARCIS (Netherlands)

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

    2006-01-01

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

  10. EFFECTS OF HURRICANE IVAN ON WATER QUALITY IN PENSACOLA BAY, FL USA

    Science.gov (United States)

    Pensacola Bay was in the strong NE quadrant of Hurricane Ivan when it made landfall on September 16, 2004 as a category 3 hurricane on the Saffir-Simpson scale. We present data describing the timeline and maximum height of the storm surge, the extent of flooding of coastal land, ...

  11. Modeling waves and longshore transport potential in Half Moon Bay, Grays Harbor, Washington, USA

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; PHILIP D Osborne

    2008-01-01

    A local-scale phase-resolving wave transformation model with CGWAVE is established in connection with a regional-scale coupled STWAVE-ADCIRC wave-current model for its application in the Half Moon Bay, Grays Harbor. Wave transformation from offshore to the harbor entrance is simulated by the STWAVE model which includes wave-current interaction. The STWAVE results provide incident wave conditions for the local-scale CGWAVE model at its outer boundary. A simple method is developed to take into ac- count the lateral variation of wave height in constructing the model's wave boundary conditions. The model was validated for three wave condition cases which yielded good agreement with field data. The validated model was applied to predicting nearshore waves in the Half Moon Bay and longshore transport parameters along the wave breaking line for the existing condition and three engi- neering alternatives. A comparative analysis indicated that storm waves that have a combination of long period and large height are the most destructive to the crenulate shoreline in the Half Moon Bay; both 152 m jetty extension (Alt. 2) and diffraction mound enlargement ( Alt. 3) would significantly reduce breaking wave height and longshore transport potential in the southwest comer of Half Moon Bay.

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

    Directory of Open Access Journals (Sweden)

    John P. Ryan

    2014-01-01

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

  13. A seasonal comparison of surface sediment characteristics in Chincoteague Bay, Maryland and Virginia, USA

    Science.gov (United States)

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

    2016-02-03

    Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of surficial sediments from Chincoteague Bay and Tom's Cove, between Assateague Island and the Delmarva Peninsula in late March/early April 2014 and October 2014. The sampling efforts were part of a larger U.S. Geological Survey study to assess the effects of storm events on sediment distribution in back-barrier environments of the United States. By sampling during the spring and fall, a more complete understanding of seasonal variability in the area can help determine baseline conditions. The objective of this study was to characterize the sediments of Chincoteague Bay in order to create baseline conditions to incorporate with the hydrodynamic and sediment transport models used to evaluate pre- and post-storm change and compare with future field measurements.

  14. Distribution of heavy metals and foraminiferal assemblages in sediments of Biscayne Bay, Florida, USA

    Science.gov (United States)

    Carnahan, E.A.; Hoare, A.M.; Hallock, P.; Lidz, B.H.; Reich, C.D.

    2008-01-01

    Heavy-metal pollution is an issue of concern in estuaries influenced by agriculture, urban, and harbor activities. Foraminiferal assemblages have been shown to be effective indicators of pollution. Sediment samples (n = 110) from Biscayne Bay were analyzed for heavy metals, foraminiferal assemblages, and grain-size distribution. Highest Cu, Zn, Cr, Hg, Pb, and Ni concentrations were found closest to Miami and near the mouths of several canals along the western margin of the bay. Few samples exceeded limits of possible biological effects as defined by previous studies. Ammonia and Cribroelphidium, two known stress-tolerant genera, correlated positively with Cu, Zn, Hg, and Ni (r ??? 0.43). Symbiont-bearing foraminifers, Archaias, Laevipeneroplis, and Androsina, correlated negatively with Cu, Zn, Hg, and Ni (r ??? -0.26).

  15. Paleoenvironmental assessment of recent environmental changes in Florida Bay, USA: A biomarker based study

    Science.gov (United States)

    Xu, Yunping; Holmes, Charles W.; Jaffé, Rudolf

    2007-06-01

    The extractable lipid compositions in four Florida Bay cores were determined in order to understand environmental changes over the last 160 years. The most significant environmental change was recorded by oscillations in the amplitude and frequency of biomarkers during the 20th century. Two seagrass molecular proxies ( Paq and the C 25/C 27n-alkan-2-one ratio) reached a maximum post 1900, suggesting that abundant seagrass communities existed during the 20th century. A sharp drop in the Paq value from 0.65 to 0.48 in the central Bay at about 1987 seems to reflect seagrass die-off. The concentrations of microbial biomarkers (C 20 HBIs, C 25 HBIs and dinosterol) substantially increased after 1950 in the TC, BA and NB cores, reflecting an increase in algal (planktonic organism) primary productivity. However, the RB core presented the highest abundance of C 25 HBIs and dinosterol during the period of 1880-1940, suggesting historically large inputs from diatoms and dinoflagellates. A substantial rise in abundance of taraxerol (a specific biomarker of mangroves) from 20 μg/g TOC in the 1830s to 279 μg/g TOC in the l980s is likely a result of increased mangrove primary productivity along the shore of the NE Bay. These changes are most likely the result of hydrological alterations in South Florida.

  16. Integrated ecosystem services assessment: Valuation of changes due to sea level rise in Galveston Bay, Texas, USA.

    Science.gov (United States)

    Yoskowitz, David; Carollo, Cristina; Pollack, Jennifer Beseres; Santos, Carlota; Welder, Kathleen

    2017-03-01

    The goal of the present study was to identify the potential changes in ecosystem service values provided by wetlands in Galveston Bay, Texas, USA, under the Intergovernmental Panel on Climate Change (IPCC) A1B max (0.69 m) sea level rise scenario. Built exclusively upon the output produced during the Sea Level Affecting Marshes Model 6 (SLAMM 6) exercise for the Galveston Bay region, this study showed that fresh marsh and salt marsh present a steady decline from 2009 (initial condition) to 2100. Fresh marsh was projected to undergo the biggest changes, with the loss of approximately 21% of its extent between 2009 and 2100 under the A1B max scenario. The percentages of change for salt marsh were less prominent at approximately 12%. This trend was also shown in the values of selected ecosystem services (disturbance regulation, waste regulation, recreation, and aesthetics) provided by these habitats. An ordinary least squares regression was used to calculate the monetary value of the selected ecosystem services provided by salt marsh and fresh marsh in 2009, and in 2050 and 2100 under the A1B max scenario. The value of the selected services showed potential monetary losses in excess of US$40 million annually in 2100, compared to 2009 for fresh marsh and more than $11 million for salt marsh. The estimates provided here are only small portions of what can be lost due to the decrease in habitat extent, and they highlight the need for protecting not only built infrastructure but also natural resources from sea level rise. Integr Environ Assess Manag 2017;13:431-443. © 2016 SETAC.

  17. Polychlorinated biphenyls in the exterior caulk of San Francisco Bay Area buildings, California, USA.

    Science.gov (United States)

    Klosterhaus, Susan; McKee, Lester J; Yee, Donald; Kass, Jamie M; Wong, Adam

    2014-05-01

    Extensive evidence of the adverse impacts of polychlorinated biphenyls (PCBs) to wildlife, domestic animals, and humans has now been documented for over 40 years. Despite the ban on production and new use of PCBs in the United States in 1979, a number of fish consumption advisories remain in effect, and there remains considerable uncertainty regarding ongoing environmental sources and management alternatives. Using a blind sampling approach, 25 caulk samples were collected from the exterior of ten buildings in the San Francisco Bay Area and analyzed for PCBs using congener-specific gas chromatography-mass spectrometry (GC-MS) and chlorine using portable X-ray fluorescence (XRF). PCBs were detected in 88% of the caulk samples collected from the study area buildings, with 40% exceeding 50 ppm. Detectable PCB concentrations ranged from 1 to 220,000 ppm. These data are consistent with previous studies in other cities that have identified relatively high concentrations of PCBs in concrete and masonry buildings built between 1950 and 1980. Portable XRF was not a good predictor of the PCB content in caulk and the results indicate that portable XRF analysis may only be useful for identifying caulk that contains low concentrations of Cl (≤ 10,000 ppm) and by extension low or no PCBs. A geographic information system-based approach was used to estimate that 10,500 kg of PCBs remain in interior and exterior caulk in buildings located in the study area, which equates to an average of 4.7 kg PCBs per building. The presence of high concentrations in the exterior caulk of currently standing buildings suggests that building caulk may be an ongoing source of PCBs to the San Francisco Bay Area environment. Further studies to expand the currently small international dataset on PCBs in caulking materials in buildings of countries that produced or imported PCBs appear justified in the context of both human health and possible ongoing environmental release.

  18. Storm surges and climate change implications for tidal marshes: Insight from the San Francisco Bay Estuary, California, USA

    Science.gov (United States)

    Thorne, Karen M.; Buffington, Kevin J.; Swanson, Kathleen; Takekawa, John Y.

    2013-01-01

    Tidal marshes are dynamic ecosystems, which are influenced by oceanic and freshwater processes and daily changes in sea level. Projected sea-level rise and changes in storm frequency and intensity will affect tidal marshes by altering suspended sediment supply, plant communities, and the inundation duration and depth of the marsh platform. The objective of this research was to evaluate if regional weather conditions resulting in low-pressure storms changed tidal conditions locally within three tidal marshes. We hypothesized that regional storms will increase sea level heights locally, resulting in increased inundation of the tidal marsh platform and plant communities. Using site-level measurements of elevation, plant communities, and water levels, we present results from two storm events in 2010 and 2011 from the San Francisco Bay Estuary (SFBE), California, USA. The January 2010 storm had the lowest recorded sea level pressure in the last 30 years for this region. During the storm episodes, the duration of tidal marsh inundation was 1.8 and 3.1 times greater than average for that time of year, respectively. At peak storm surges, over 65% in 2010 and 93% in 2011 of the plant community was under water. We also discuss the implications of these types of storms and projected sea-level rise on the structure and function of the tidal marshes and how that will impact the hydro-geomorphic processes and marsh biotic communities.

  19. Modeling the impacts of winter cover crops on water quality in two adjacent sub-watersheds within the Chesapeake Bay Watershed, Maryland, USA

    Science.gov (United States)

    The Choptank River on Maryland’s Eastern Shore has been designated by the USEPA as “impaired waters” under Section 303(d) of the Federal Clean Water Act of 1972, mainly because of significant nutrient loads that resulted in not meeting the EPA water quality standards. This water quality deteriorati...

  20. 土地利用及不透水地表对河流流量的影响%Impacts of Land Use and Impervious Surface on Stream Flow Metrics in Chesapeake Bay Watershed

    Institute of Scientific and Technical Information of China (English)

    田迪; 李叙勇; Donald E. Weller; 白中科

    2011-01-01

    Using daily discharge data from the US Geological Survey, we calculated 34 stream flow metrics for 150 watersheds (area <282 km ) within the Chesapeake Bay basin, and selected 17 of the metrics. We quantified the proportions of forest, agriculture, grassland, developed land, and impervious surface in each watershed. For each of the three physiographic provinces, we correlated the flow metrics with the land cover proportions to elucidate how different land cover types affect the flow regime. Higher proportions of forest increased stream flow in relatively dry winters or springs and reduced stream flow in comparatively rainy autumns. Higher forest proportions also reduced flooding, prolonged pulses of higher flow, and reduced flow variability. Higher proportions of agriculture reduced flow variability and prolonged pulses of higher flow in all physiographic provinces and reduced flooding in the highland physiographic provinces. Higher grassland proportions reduced flooding and flow variability and prolonged high flow pulses in all provinces. Higher proportions of developed land and impervious surface reduced infiltration, increased flooding and flow during high rainfall periods, intensified flow variability, and shortened high flow pulses; there are different hydrologic effects in different urbanized areas.%利用美国地质调查局的逐日连续流量数据计算了美国切斯比克湾地区150个小流域的34个河流流量指标,并在整个区域和划分的3个自然地理区对选择的17个指标与4种土地利用类型和不透水地表做了相关分析。结果表明,森林在降水较少的冬春两季增加流量,雨量较高的秋季减少流量,森林面积比例的增加可以削减洪峰、延长洪峰历时、稳定流量变化。农业用地比例的增加表现为稳定流量变化,延长洪峰历时,在高原地区还可以削减洪峰流量。草地比例的提高均表现为削减洪峰流量,稳定流量变化,延长洪

  1. Canvasback Food Habits in Chesapeake Bay

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Food habits analyses were conducted on the gullet and gizzards of 153 canvasbacks (Aythya valisineria) collected at night from eight major wintering areas in...

  2. Macrobenthic Communities of the Lower Chesapeake Bay.

    Science.gov (United States)

    1984-10-01

    ECHINODERMATA :ECHINOIDEA Arbacij Runlctulata (Lamarck) Echinarachnius Parma (Larmack) ECHINODERMATA :HOLOTHURO-DEA Holothuroidea spp. Leptosynapta ... inhaerens (Ayres) ECHINODERMATA :OPHIUROIDEA Ophiuroidea spp. * HEMICHORDATA Saccoglossus kowalewskii (Agassiz) CHORDATA :CEPHALOCHORDATA Branchiostoma

  3. Intra- and inter-annual trends in phosphorus loads and comparison with nitrogen loads to Rehoboth Bay, Delaware (USA)

    Science.gov (United States)

    Volk, J.A.; Scudlark, J.R.; Savidge, K.B.; Andres, A.S.; Stenger, R.J.; Ullman, W.J.

    2012-01-01

    Monthly phosphorus loads from uplands, atmospheric deposition, and wastewater to Rehoboth Bay (Delaware) were determined from October 1998 to April 2002 to evaluate the relative importance of these three sources of P to the Bay. Loads from a representative subwatershed were determined and used in an areal extrapolation to estimate the upland load from the entire watershed. Soluble reactive phosphorus (SRP) and dissolved organic P (DOP) are the predominant forms of P in baseflow and P loads from the watershed are highest during the summer months. Particulate phosphorus (PP) becomes more significant in stormflow and during periods with more frequent or larger storms. Atmospheric deposition of P is only a minor source of P to Rehoboth Bay. During the period of 1998-2002, wastewater was the dominant external source of P to Rehoboth Bay, often exceeding all other P sources combined. Since 2002, however, due to technical improvements to the sole wastewater plant discharging directly to the Bay, the wastewater contribution of P has been significantly reduced and upland waters are now the principal source of P on an annualized basis. Based on comparison of N and P loads, primary productivity and biomass carrying capacity in Rehoboth Bay should be limited by P availability. However, due to the contrasting spatial and temporal patterns of N and P loading and perhaps internal cycling within the ecosystem, spatial and temporal variations in N and P-limitation within Rehoboth Bay are likely. ?? 2011 Elsevier Ltd.

  4. Emerging coral diseases in Kāne'ohe Bay, O'ahu, Hawai'i (USA): two major disease outbreaks of acute Montipora white syndrome

    Science.gov (United States)

    Aeby, Greta S.; Callahan, Sean; Cox, Evelyn F.; Runyon, Christina M.; Smith, Ashley; Stanton, Frank G.; Ushijima, Blake; Work, Thierry M.

    2016-01-01

    In March 2010 and January 2012, we documented 2 widespread and severe coral disease outbreaks on reefs throughout Kāne‘ohe Bay, Hawai‘i (USA). The disease, acute Montipora white syndrome (aMWS), manifested as acute and progressive tissue loss on the common reef coral M. capitata. Rapid visual surveys in 2010 revealed 338 aMWS-affected M. capitata colonies with a disease abundance of (mean ± SE) 0.02 ± 0.01 affected colonies per m of reef surveyed. In 2012, disease abundance was significantly higher (1232 aMWS-affected colonies) with 0.06 ± 0.02 affected colonies m-1. Prior surveys found few acute tissue loss lesions in M. capitata in Kāne‘ohe Bay; thus, the high number of infected colonies found during these outbreaks would classify this as an emerging disease. Disease abundance was highest in the semi-enclosed region of south Kāne‘ohe Bay, which has a history of nutrient and sediment impacts from terrestrial runoff and stream discharge. In 2010, tagged colonies showed an average tissue loss of 24% after 1 mo, and 92% of the colonies continued to lose tissue in the subsequent month but at a slower rate (chronic tissue loss). The host-specific nature of this disease (affecting only M. capitata) and the apparent spread of lesions between M. capitatacolonies in the field suggest a potential transmissible agent. The synchronous appearance of affected colonies on multiple reefs across Kāne‘ohe Bay suggests a common underlying factor. Both outbreaks occurred during the colder, rainy winter months, and thus it is likely that some parameter(s) associated with winter environmental conditions are linked to the emergence of disease outbreaks on these reefs.

  5. Pressure and temperature profile data collected by the NOAA vessel Bay Hydrographer during survey operations along the NE US coast, 03 February 2005 to 21 November 2005 (NODC Accession 0002670)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Pressure and temperature profile data were collected using CTD casts from the NOAA Survey Vessel BAY HYDROGRAPHER. Data were collected in the Chesapeake Bay from...

  6. DINOFLAGELLATE CYST RECORDS AND HUMAN DISTURBANCE IN TWO NEIGHBORING ESTUARIES, NEW BEDFORD HARBOR AND APPONAGANSETT BAY, MASSACHUSETTS, USA

    Science.gov (United States)

    The dinoflagellate cyst records in sediments from New Bedford Harbor and Apponagansett Bay demonstrate sensitivity to environmental change caused by human activity in the watersheds over the last 500 years. Changes in the species richness, as well as absolute and relative abundan...

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

    Science.gov (United States)

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

    2015-10-01

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

  8. GRACILARIA VERMICULOPHYLLA (RHODOPHYTA, GRACILARIALES) IN THE VIRGINIA COASTAL BAYS, USA: COX1 ANALYSIS REVEALS HIGH GENETIC RICHNESS OF AN INTRODUCED MACROALGA.

    Science.gov (United States)

    Gulbransen, Dana J; McGlathery, Karen J; Marklund, Maria; Norris, James N; Gurgel, Carlos Frederico D

    2012-10-01

    Gracilaria vermiculophylla (Ohmi) Papenfuss is an invasive alga that is native to Southeast Asia and has invaded many estuaries in North America and Europe. It is difficult to differentiate G. vermiculophylla from native forms using morphology and therefore molecular techniques are needed. In this study, we used three molecular markers (rbcL, cox2-cox3 spacer, cox1) to identify G. vermiculophylla at several locations in the western Atlantic. RbcL and cox2-cox3 spacer markers confirmed the presence of G. vermiculophylla on the east coast of the USA from Massachusetts to South Carolina. We used a 507 base pair region of cox1 mtDNA to (i) verify the widespread distribution of G. vermiculophylla in the Virginia (VA) coastal bays and (ii) determine the intraspecific diversity of these algae. Cox1 haplotype richness in the VA coastal bays was much higher than that previously found in other invaded locations, as well as some native locations. This difference is likely attributed to the more intensive sampling design used in this study, which was able to detect richness created by multiple, diverse introductions. On the basis of our results, we recommend that future studies take differences in sampling design into account when comparing haplotype richness and diversity between native and non-native studies in the literature.

  9. An evaluation of temporal changes in sediment accumulation and impacts on carbon burial in Mobile Bay, Alabama, USA

    Science.gov (United States)

    Smith, Christopher G.; Osterman, Lisa E.

    2014-01-01

    The estuarine environment can serve as either a source or sink of carbon relative to the coastal ocean carbon budget. A variety of time-dependent processes such as sedimentation, carbon supply, and productivity dictate how estuarine systems operate, and Mobile Bay is a system that has experienced both natural and anthropogenic perturbations that influenced depositional processes and carbon cycling. Sediments from eight box cores provide a record of change in bulk sediment accumulation and carbon burial over the past 110 years. Accumulation rates in the central part of the basin (0.09 g cm−2) were 60–80 % less than those observed at the head (0.361 g cm−2) and mouth (0.564 g cm−2) of the bay. Sediment accumulation in the central bay decreased during the past 90 years in response to both anthropogenic (causeway construction) and natural (tropical cyclones) perturbations. Sediment accumulation inevitably increased the residence time of organic carbon in the oxic zone, as observed in modeled remineralization rates, and reduced the overall carbon burial. Such observations highlight the critical balance among sediment accumulation, carbon remineralization, and carbon burial in dynamic coastal environments. Time-series analysis based solely on short-term observation would not capture the long-term effects of changes in sedimentation on carbon cycling. Identifying these relationships over longer timescales (multi-annual to decadal) will provide a far better evaluation of coastal ocean carbon budgets.

  10. Avian morbidity and mortality from botulism, aspergillosis, and salmonellosis at Jamaica Bay Wildlife Refuge, New York, USA

    Science.gov (United States)

    Brand, C.J.; Windingstad, R.M.; Siegfried, L.M.; Duncan, R.M.; Cook, R.M.

    1988-01-01

    During the summers of 1981 and 1982, studies were conducted at Jamaica Bay Wildlife Refuge, Long Island, New York, to determine whether annual water-level drawdowns used to create shorebird habitat also led to the occurrence of avian botulism (Clostridium botulinum type C). Low levels of morbidity and mortality from avian botulism occurred on the two ponds throughout both summers, but there was no apparent relationship between the occurrence or rates of botulism losses and drawdowns of the ponds. Botulism also occurred throughout both summers on other areas of the refuge. Botulinal toxin was found in fly larvae associated with avian carcasses, including birds that did not die from botulism. Toxin was not found in other samples of aquatic biota in the ponds, although it was demonstrated in a single sample of decomposing sea lettuce (Ulva lactuca) in Jamaica Bay. Aspergillosis (Aspergillus fumigatus) and salmonellosis (Salmonella spp.) were also frequently-diagnosed causes of morbidity and mortality. We believe that botulinal toxin present in carcasses of birds dying from botulism, or produced postmortem in birds dying from other causes, on the two ponds and other areas in Jamaica Bay were a major source of botulinal toxin. Toxin could be ingested by birds through direct scavenging on carcasses, or by consumption of toxic fly larvae associated with carcasses. Diligent carcass pickup at the two ponds is recommended to reduce mortality from avian botulism.

  11. Temporal and spatial distributions of sediment mercury at salt pond wetland restoration sites, San Francisco Bay, CA, USA

    Science.gov (United States)

    Miles, A.K.; Ricca, M.A.

    2010-01-01

    Decommissioned agricultural salt ponds within south San Francisco Bay, California, are in the process of being converted to habitat for the benefit of wildlife as well as water management needs and recreation. Little is known of baseline levels of contaminants in these ponds, particularly mercury (Hg), which has a well established legacy in the Bay. In this study we described spatial and short-term temporal variations in sediment Hg species concentrations within and among the Alviso and Eden Landing salt ponds in the southern region of San Francisco Bay. We determined total Hg (Hgt) and methylmercury (MeHg) in the top 5 cm of sediment of most ponds in order to establish baseline conditions prior to restoration, sediment Hgt concentrations in a subset of these ponds after commencement of restoration, and variation in MeHg concentrations relative to sediment Hgt, pH, and total Fe concentrations and water depth and salinity in the subset of Alviso ponds. Inter-pond differences were greatest within the Alviso pond complex, where sediment Hgt concentrations averaged (arithmetic mean) 0.74 ??g/g pre and 1.03 ??g/g post-restoration activity compared to 0.11 ??g/g pre and post at Eden Landing ponds. Sediment Hgt levels at Alviso were fairly stable temporally and spatially, whereas MeHg levels were variable relative to restoration activities across time and space. Mean (arithmetic) sediment MeHg concentrations increased (2.58 to 3.03 ng/g) in Alviso and decreased (2.20 to 1.03 ng/g) in Eden Landing restoration ponds during the study. Differences in MeHg levels were related to water depth and pH, but these relationships were not consistent between years or among ponds and were viewed with caution. Factors affecting MeHg levels in these ponds (and in general) are highly complex and require in-depth study to understand.

  12. Effect of the South Bay Ocean Outfall (SBOO) on ocean beach water quality near the USA-Mexico border.

    Science.gov (United States)

    Gersberg, Richard; Tiedge, Jürgen; Gottstein, Dana; Altmann, Sophie; Watanabe, Kayo; Lüderitz, Volker

    2008-04-01

    In early 1999, primary treatment and discharge of sewage from Tijuana, Mexico (approximately 95 million liters per day) began through South Bay Ocean Outfall (SBOO) into the ocean 4.3 km offshore. In this study, statistical comparisons were made of the bacterial water quality (total and fecal coliforms and enterococci densities) of the ocean, both before and after discharge of sewage to the SBOO began, so that the effect of this ocean discharge on nearshore ocean water quality could be quantitatively assessed. The frequency of exceedence of bacterial indicator thresholds was statistically analyzed for 11 shore (surfzone) stations throughout US and Mexico using the Fisher's exact test, for the years before (1995-1998) as compared to after the SBOO discharge began (1999-2003). Only four of the 11 shoreline stations (S2, S3, S11, and S12) showed significant improvement (decreased frequency of exceedence of bacterial indicator thresholds) after SBOO discharge began.

  13. From Sediment to Top Predators: Broad Exposure of Polyhalogenated Carbazoles in San Francisco Bay (U.S.A.).

    Science.gov (United States)

    Wu, Yan; Tan, Hongli; Sutton, Rebecca; Chen, Da

    2017-02-21

    The present study provides the first comprehensive investigation of polyhalogenated carbazoles (PHCZs) contamination in an aquatic ecosystem. PHCZs have been found in soil and aquatic sediment from several different regions, but knowledge of their bioaccumulation and trophodynamics is extremely scarce. This work investigated a suite of 11 PHCZ congeners in San Francisco Bay (United States) sediment and organisms, including bivalves (n = 6 composites), sport fish (n = 12 composites), harbor seal blubber (n = 18), and bird eggs (n = 8 composites). The most detectable congeners included 3,6-dichlorocarbazole (36-CCZ), 3,6-dibromocarbazole (36-BCZ), 1,3,6-tribromocarbazole (136-BCZ), 1,3,6,8-tetrabromocarbazole (1368-BCZ), and 1,8-dibromo-3,6-dichlorocarbazole (18-B-36-CCZ). The median concentrations of ΣPHCZs were 9.3 ng/g dry weight in sediment and ranged from 33.7 to 164 ng/g lipid weight in various species. Biomagnification was observed from fish to harbor seal and was mainly driven by chlorinated carbazoles, particularly 36-CCZ. Congener compositions of PHCZs differed among species, suggesting that individual congeners may be subject to different bioaccumulation or metabolism in species occupying various trophic levels in the studied aquatic system. Toxic equivalent (TEQ) values of PHCZs were determined on the basis of their relative effect potencies (REP) compared to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The median TEQ was 1.2 pg TEQ/g dry weight in sediment and 4.8-19.5 pg TEQ/g lipid weight in biological tissues. Our study demonstrated the broad exposure of PHCZs in San Francisco Bay and their characteristics of bioaccumulation and biomagnification along with dioxin-like effects. These findings raise the need for additional research to better elucidate their sources, environmental behavior, and fate in global environments.

  14. Sedimentary organic biomarkers suggest detrimental effects of PAHs on estuarine microbial biomass during the 20th century in San Francisco Bay, CA, USA

    Science.gov (United States)

    Nilsen, Elena B.; Rosenbauer, Robert J.; Fuller, Christopher C.; Jaffe, Bruce E.

    2014-01-01

    Hydrocarbon contaminants are ubiquitous in urban aquatic ecosystems, and the ability of some microbial strains to degrade certain polycyclic aromatic hydrocarbons (PAHs) is well established. However, detrimental effects of petroleum hydrocarbon contamination on nondegrader microbial populations and photosynthetic organisms have not often been considered. In the current study, fatty acid methyl ester (FAME) biomarkers in the sediment record were used to assess historical impacts of petroleum contamination on microbial and/or algal biomass in South San Francisco Bay, CA, USA. Profiles of saturated, branched, and monounsaturated fatty acids had similar concentrations and patterns downcore. Total PAHs in a sediment core were on average greater than 20× higher above ∼200 cm than below, which corresponds roughly to the year 1900. Isomer ratios were consistent with a predominant petroleum combustion source for PAHs. Several individual PAHs exceeded sediment quality screening values. Negative correlations between petroleum contaminants and microbial and algal biomarkers – along with high trans/cis ratios of unsaturated FA, and principle component analysis of the PAH and fatty acid records – suggest a negative impacts of petroleum contamination, appearing early in the 20th century, on microbial and/or algal ecology at the site.

  15. Field exposure of frog embryos and tadpoles along a pollution gradient in the Fox River and Green Bay ecosystem in Wisconsin, Usa.

    Science.gov (United States)

    Karasov, William H; Jung, Robin E; Langenberg, Susan Vanden; Bergeson, Tara L E

    2005-04-01

    We raised embryos and tadpoles of green frogs (Rana clamitans melanota) and leopard frogs (R. pipiens) in situ along a contamination gradient in the Fox River/Green Bay ecosystem (WI, USA). Differences in exposure were reflected by significant positive regressions between concentrations in sediment and in frogs of polychlorinated biphenyl (PCB) congeners and some heavy metals (Cd, Cr, and Pb), which could have predictive value for estimating exposure of amphibians to contaminants in this ecosystem and, perhaps, in others. On average, non-ortho-substituted coplanar PCBs made up a very small percentage (average, 0.2%) of the PCB congeners in all samples analyzed, with larger fractions accounted for by mono- and di-ortho congeners (average, 19%) and routine congeners (average, 81%). Hatchability of frog embryo batches and anuran species richness at the sites were negatively correlated with level of contamination, but tadpole growth and survival were not. Sediment and tissue levels of PCBs and metals generally were correlated with each other, confounding the association of effects on frogs with any particular contaminant. It is also plausible that high levels of un-ionized ammonia (NH3) reduced hatching success of green frog, but not leopard frog, embryos in the field enclosures. Other environmental factors that were present but unmeasured in the field, such as ultraviolet-B radiation as well as water flow and level fluctuations, might have caused differences in hatching success at the field sites.

  16. GPS Instrumentation and Remote Sensing Study of Slow Moving Landslides in the Eastern San Francisco Bay Hills, California, USA

    Science.gov (United States)

    Cohen-Waeber, J.; Burgmann, R.; Sitar, N.; Ferretti, A.; Giannico, C.

    2012-12-01

    The objective of this study is to characterize slope deformation as a result of static and dynamic forces, using the most current geodetic technologies that measure active ground surface displacement. Recent advances in geodetic and remote data collection, such as with continuous GPS and Interferometric Synthetic Aperture Radar (InSAR) allow for a level of primary site characterization and eventual risk assessment due to landsliding that was previously not possible. Active landsliding across the Lawrence Berkeley National Laboratory (LBNL) site and the greater Berkeley Hills region, in the Eastern San Francisco Bay, California, has been the object of many investigations over recent decades, though the mechanisms of currently mobile slides are still poorly understood. Previous studies suggest a trend in landslide mobility is closely associated with precipitation and regional active tectonic conditions in addition to the geologic setting (Alan Kropp and Associates, 2002). InSAR time-series analysis has been shown to successfully track creeping landslides in the Berkeley Hills with millimeter scale accuracy (Hilley et al., 2004) and documents displacement primarily during periods of high precipitation (Quigley et al., 2010). However, displacement of creeping landslides due to seismic activity has yet to be measured. A first focus of this project is therefore to study the spatial and temporal distribution of active Berkeley Hills landsliding in relation to local precipitation and ground shaking events by a careful observational program. This program includes the instrumentation of individual landslides with permanent continuously streaming GPS stations (beginning 2012), and regional monitoring of slope surface deformation by InSAR time series analysis (beginning 1992). To date, continuous GPS tracking of select landslides has recorded up to 2 cm of total surface deformation driven by the onset of precipitation, with displacement response times of less than 5 days

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

    Science.gov (United States)

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

    1998-01-01

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

  18. Chesapeake Inundation Prediction System (CIPS): A regional prototype for a national problem

    Science.gov (United States)

    Stamey, B.; Smith, W.; Carey, K.; Garbin, D.; Klein, F.; Wang, Hongfang; Shen, J.; Gong, W.; Cho, J.; Forrest, D.; Friedrichs, C.; Boicourt, W.; Li, M.; Koterba, M.; King, D.; Titlow, J.; Smith, E.; Siebers, A.; Billet, J.; Lee, J.; Manning, Douglas R.; Szatkowski, G.; Wilson, D.; Ahnert, P.; Ostrowski, J.

    2007-01-01

    Recent Hurricanes Katrina and Isabel, among others, not only demonstrated their immense destructive power, but also revealed the obvious, crucial need for improved storm surge forecasting and information delivery to save lives and property in future storms. Current operational methods and the storm surge and inundation products do not adequately meet requirements needed by Emergency Managers (EMs) at local, state, and federal levels to protect and inform our citizens. The Chesapeake Bay Inundation Prediction System (CIPS) is being developed to improve the accuracy, reliability, and capability of flooding forecasts for tropical cyclones and non-tropical wind systems such as nor'easters by modeling and visualizing expected on-land storm-surge inundation along the Chesapeake Bay and its tributaries. An initial prototype has been developed by a team of government, academic and industry partners through the Chesapeake Bay Observing System (CBOS) of the Mid-Atlantic Coastal Ocean Observing Regional Association (MACOORA) within the Integrated Ocean Observing System (IOOS). For demonstration purposes, this initial prototype was developed for the tidal Potomac River in the Washington, DC metropolitan area. The preliminary information from this prototype shows great potential as a mechanism by which NOAA National Weather Service (NWS) Forecast Offices (WFOs) can provide more specific and timely forecasts of likely inundation in individual localities from significant storm surge events. This prototype system has shown the potential to indicate flooding at the street level, at time intervals of an hour or less, and with vertical resolution of one foot or less. This information will significantly improve the ability of EMs and first responders to mitigate life and property loss and improve evacuation capabilities in individual communities. This paper provides an update and expansion of the initial prototype that was presented at the Oceans 2006 MTS/IEEE Conference in Boston, MA

  19. Chesapeake Bay Water Quality Monitoring Using Satellite Imagery Project

    Data.gov (United States)

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

  20. Chesapeake Bay Future Conditions Report. Volume 11. Biota.

    Science.gov (United States)

    1977-12-01

    decayed organ isms , etc. Organic sediments are also formed by fecal and pseudofecal pellets excreted by benthic organisms (Moore , 1955) and by sedi...vitamins, organic colloids and organic fragments Intermixed with various proportions of clay silt , fine sand and living microbiota ” (Carriker... transplanted into En glish waters , but inadvertently intro- duced at the same time was Urosalpinx cinerea , an oyster drill now recognized as an extensive

  1. Task 0715: Army Chesapeake Bay Total Maximum Daily Load Pilots

    Science.gov (United States)

    2011-05-01

    NDCEE/CTC The NDCEE is operated by: Office of the Assistant Sec etary of the Army for Installations, E ergy and Enviro ment Technology Transition...Center for Energy and Environment 4) Guidebook and Training Development/Delivery (Future)  Guidebook – Capture lessons learned from implementation of

  2. Effects of Aluminized Fiberglass on Representative Chesapeake Bay Marine Organisms

    Science.gov (United States)

    1977-11-23

    hours of feeding by test oysters, Cra~sostrea virgnica. Long Forjm: Starting Density: 1.303 x 106 Control lOOX lODOX .259 x 105 .297 .549 .607 .324 .694...100 19 100 39 100 Table 13 Wet weights of !Iytilus edulis. Wet Weight (grams) Concentration Day 0 Day 21 Replicate 1 173.3 173.4 lOOX 213.8 213.7 lODOX ...182.1 187.0 Crlct 162.3 160.1 (1dead) lOOX 193.1 195.7 lOQOX 148.4 148.7 Replicate 3 Control 143.2 158.8 1 OOX 183.0 176.0 (1 dead) lODOX 164.5 158.8

  3. Wetland Habitats for Wildlife of the Chesapeake Bay

    Data.gov (United States)

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

  4. Bioassay of Surface Quality/Chesapeake Bay, Maryland

    Science.gov (United States)

    1995-02-01

    Karr, 1981). Algae have been used as biomonitoring tools for quite some time (Kolkwitz and Marsson, 1908; Hentschel , 1925; Nauman, 1925; Butcher, 1947...characteristic of a particular zone or condition may or may not occur there and may actually appear elsewhere ( Hentschel , 1925; Nauman, 1932; -. Butcher, 1947...High Quaility Diversity L - Low Quality 1.9 b• Principio( 1.787)H Byrd(1.734)1i 1.71 Fork(.630)I- 1. Little Byrd(l.549)H I Parnunkey(L545)]i " Elk

  5. Chesapeake Bay Analysis using Time and Spatial Generalized Eigenfunctions

    Science.gov (United States)

    2007-10-05

    solved using NMA. The basic unit of calculation used throughout this pa- per is the normal mode. Like the modes of a guitar string or an organ pipe...n g(t2)N,n     ACn BCn ADn BDn   =   αn γn βn ∆n     g(t1)D,n g(t2)D,n g(t1)N,n g(t2)N,n   −1 6 Figure 1: Guitar String 7 t 1 t...set, the requirement is that all functions spanning the space have a zero in- tegral when considering the product of any two modes over the do- main

  6. Chesapeake Bay Study. Supplement A. Problem Identification. Supplement B. Public Involvement. Supplement C. The Chesapeake Bay Hydraulic Model.

    Science.gov (United States)

    1984-09-01

    beaches and wetlands which serve as a buffer between the water body and the fastland. Lastly, the nearshore extends waterward from the mean low water...6U ) 0 8 0))~~...4...6...6 ~ ~ ~ L 4) 4 400 U 4𔄂)C . L .4 IVF ’ j~4 )4.004~ 0U) . . .C.. - ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~B 1C6.3.>,. ,0LU~6 .40.~l )). c41

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

    Science.gov (United States)

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

    2011-01-01

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

  8. The Chesapeake Laser Tracker in Industrial Metrology

    Energy Technology Data Exchange (ETDEWEB)

    Ruland, Robert E.; /SLAC

    2005-08-16

    In the summer of 1992, the survey and alignment team at the Stanford Linear Accelerator Center acquired a CMS3000 laser tracker manufactured by Chesapeake Laser Systems in Lanham, Maryland. This paper gives a description of the principles of operation and calibration of the tracker. Several applications are explained and the results shared.

  9. Monitoring and modeling nitrate fate in subbasins within the Choptank River Watershed, Maryland, USA

    Science.gov (United States)

    Conservation practices, such as post harvest planting of winter cover crops, are important for water quality improvement in agricultural watersheds. Throughout the Chesapeake Bay watershed (CBW), winter cover crop use has been emphasized and federal and state cost-share programs are available for fa...

  10. Assessment and Mmanagement of North American horseshoe crab populations, with emphasis on a multispecies framework for Delaware Bay, U.S.A. populations: Chapter 24

    Science.gov (United States)

    Millard, Michael J.; Sweka, John A.; McGowan, Conor P.; Smith, David R.

    2015-01-01

    The horseshoe crab fishery on the US Atlantic coast represents a compelling fishery management story for many reasons, including ecological complexity, health and human safety ramifications, and socio-economic conflicts. Knowledge of stock status and assessment and monitoring capabilities for the species have increased greatly in the last 15 years and permitted managers to make more informed harvest recommendations. Incorporating the bioenergetics needs of migratory shorebirds, which feed on horseshoe crab eggs, into the management framework for horseshoe crabs was identified as a goal, particularly in the Delaware Bay region where the birds and horseshoe crabs exhibit an important ecological interaction. In response, significant effort was invested in studying the population dynamics, migration ecology, and the ecologic relationship of a key migratory shorebird, the Red Knot, to horseshoe crabs. A suite of models was developed that linked Red Knot populations to horseshoe crab populations through a mass gain function where female spawning crab abundance determined what proportion of the migrating Red Knot population reached a critical body mass threshold. These models were incorporated in an adaptive management framework wherein optimal harvest decisions for horseshoe crab are recommended based on several resource-based and value-based variables and thresholds. The current adaptive framework represents a true multispecies management effort where additional data over time are employed to improve the predictive models and reduce parametric uncertainty. The possibility of increasing phenologic asynchrony between the two taxa in response to climate change presents a potential challenge to their ecologic interaction in Delaware Bay.

  11. 33 CFR 117.235 - Chesapeake and Delaware Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Chesapeake and Delaware Canal. 117.235 Section 117.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Delaware § 117.235 Chesapeake and Delaware Canal. The draw of the Conrail bridge, mile...

  12. Spatial and temporal variation of stream chemistry associated with contrasting geology and land-use patterns in the Chesapeake Bay watershed—Summary of results from Smith Creek, Virginia; Upper Chester River, Maryland; Conewago Creek, Pennsylvania; and Difficult Run, Virginia, 2010–2013

    Science.gov (United States)

    Hyer, Kenneth E.; Denver, Judith M.; Langland, Michael J.; Webber, James S.; Böhlke, J.K.; Hively, W. Dean; Clune, John W.

    2016-11-17

    Despite widespread and ongoing implementation of conservation practices throughout the Chesapeake Bay watershed, water quality continues to be degraded by excess sediment and nutrient inputs. While the Chesapeake Bay Program has developed and maintains a large-scale and long-term monitoring network to detect improvements in water quality throughout the watershed, fewer resources have been allocated for monitoring smaller watersheds, even though water-quality improvements that may result from the implementation of conservation practices are likely to be first detected at smaller watershed scales.In 2010, the U.S. Geological Survey partnered with the U.S. Environmental Protection Agency and the U.S. Department of Agriculture to initiate water-quality monitoring in four selected small watersheds that were targeted for increased implementation of conservation practices. Smith Creek watershed is an agricultural watershed in the Shenandoah Valley of Virginia that is dominated by cattle and poultry production, and the Upper Chester River watershed is an agricultural watershed on the Eastern Shore of Maryland that is dominated by row-cropping activities. The Conewago Creek watershed is an agricultural watershed in southeastern Pennsylvania that is characterized by mixed agricultural activities. The fourth watershed, Difficult Run, is a suburban watershed in northern Virginia that is dominated by medium density residential development. The objective of this study was to investigate spatial and temporal variations in water chemistry and suspended sediment in these four relatively small watersheds that represent a range of land-use patterns and underlying geology to (1) characterize current water-quality conditions in these watersheds, and (2) identify the dominant sources, sinks, and transport processes in each watershed.The general study design involved two components. The first included intensive routine water-quality monitoring at an existing streamgage within each study

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

    Brothers, Laura L.; Kelley, Joseph T.; Belknap, Daniel F.; Barnhardt, Walter A.; Andrews, Brian D.; Maynard, Melissa Landon

    2011-01-01

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

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

    Science.gov (United States)

    Conaway, Christopher H; Storlazzi, Curt D; Draut, Amy E; Swarzenski, Peter W

    2013-06-01

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

  16. The effect of freshwater inflow on meiofaunal consumption of sediment bacteria and microphytobenthos in San Antonio Bay, Texas, U.S.A.

    Science.gov (United States)

    Montagna, Paul A.; Yoon, Won Bae

    1991-12-01

    If meiofauna are food-limited then they should respond with increased feeding rates when microbial production is stimulated. River inflow into estuaries is a source of organic matter that can be limiting to bacterial production, and nutrients that might limit primary production. Therefore, inflow should stimulate microbial primary and secondary production, and eventually meiofauna grazing rates should increase as a functional response to increased food availability and quality. To determine if meiofauna grazing rates were affected by inflow, two replicate stations were sampled in the upper, river-dominated end, of San Antonio Bay and contrasted with two replicate stations at the lower end of the estuary. The experiments were performed three times. Water column nutrients and sediment organic matter were higher in the upper end of the estuary than in the lower end. Benthic primary production was 2·5 times higher in the upper end than in the lower end. Benthic metabolism (measured by oxygen consumption) was also higher in the upper end, but bacterial production (measured by thymidine uptake) was not significantly different between the two ends. Grazing rates were 3·5 times higher on bacteria, and 2·5 times higher on microalgae in the upper end of the estuary than in the lower end, confirming our hypothesis that inflow would stimulate grazing rates. Grazing rates were dominated by juvenile molluscs (temporary meiofauna) which accounted for 39% of the microalgae and 68% of the bacteria ingested by the community. Juvenile molluscs were most prevalent in the upper, fresh-water zone. Harpacticoid copepods and nematodes had higher grazing rates in the lower end of the estuary. Grazing rates were higher on microalgae than on bacteria: 4% of the microalgae were removed per hour, compared to only 1% of the bacteria. Grazing rates on microalgae were 2·6 times higher than productivity, indicating meiofauna might be food-limited. Grazing on bacteria was low, and production

  17. Chesapeake Marshlands National Wildlife Refuge Complex Annual Narrative 2000

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chesapeake Marshlands National Wildlife Refuge Complex outlines Refuge accomplishments during the 2000 calendar year. The report...

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

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2014-01-01

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

  20. 77 FR 64980 - Chesapeake Renewable Energy LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2012-10-24

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

  1. 78 FR 44556 - Chesapeake Energy Marketing, Inc. v. Midcontinent Express Pipeline LLC; Notice of Complaint

    Science.gov (United States)

    2013-07-24

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Chesapeake Energy Marketing, Inc. v. Midcontinent Express Pipeline LLC... Energy Regulatory Commission (Commission), 18 CFR 385.206, Chesapeake Energy Marketing, Inc. (CEMI...

  2. Atmospheric ammonia measurements at low concentration sites in the northeastern USA: implications for total nitrogen deposition and comparison with CMAQ estimates

    Science.gov (United States)

    We evaluated the relative importance of dry deposition of ammonia (NH3) gas at several headwater areas of the Susquehanna River, the largest single source of nitrogen pollution to Chesapeake Bay, including three that are remote from major sources of NH3 emissions (CTH, ARN, and K...

  3. Use of the soil and water assessment tool to assess winter cover crop nutrient uptake efficiency in the Choptank River Watershed, USA

    Science.gov (United States)

    The Choptank River on Maryland’s Eastern Shore, a major tributary of the Chesapeake Bay, has been designated by the USEPA as “impaired waters” under Section 303(d) of the US Federal Clean Water Act of 1972. It has been reported that water quality deterioration in most rivers is the result of excessi...

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

    Science.gov (United States)

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

    2016-06-23

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

  5. Galveston Bay

    Science.gov (United States)

    Handley, Lawrence R.; Spear, Kathryn A.; Eleonor Taylor,; Thatcher, Cindy

    2011-01-01

    The Galveston Bay estuary is located on the upper Texas Gulf coast (Lester and Gonzalez, 2002). It is composed of four major sub-bays—Galveston, Trinity, East, and West Bays. It is Texas’ largest estuary on the Gulf Coast with a total area of 155,399 hectares (384,000 acres) and 1,885 km (1,171 miles) of shoreline (Burgan and Engle, 2006). The volume of the bay has increased over the past 50 years due to subsidence, dredging, and sea level rise. Outside of ship channels, the maximum depth is only 3.7 m (12 ft), with the average depth ranging from 1.2 m (4 ft) to 2.4 m (8 ft)— even shallower in areas with widespread oyster reefs (Lester and Gonzalez, 2002). The tidal range is less than 0.9 m (3 ft), but water levels and circulation are highly influenced by wind. The estuary was formed in a drowned river delta, and its bayous were once channels of the Brazos and Trinity Rivers. Today, the watersheds surrounding the Trinity and San Jacinto Rivers, along with many other smaller bayous, feed into the bay. The entire Galveston Bay watershed is 85,470 km2 (33,000 miles2 ) large (Figure 1). Galveston Island, a 5,000 year old sand bar that lies at the western edge of the bay’s opening into the Gulf of Mexico, impedes the freshwater flow of the Trinity and San Jacinto Rivers into the Gulf, the majority of which comes from the Trinity. The Bolivar Peninsula lies at the eastern edge of the bay’s opening into the Gulf. Water flows into the Gulf at Bolivar Roads, 1 U.S. Geological Survey National Wetlands Research Center, 700 Cajundome Blvd., Lafayette, LA 70506 2 Harte Research Institute for Gulf of Mexico Studies, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Unit 5869, Corpus Christi, Texas 78412 2 Galveston Pass, between Galveston Island and Bolivar Peninsula, and at San Luis Pass, between the western side of Galveston Island and Follets Island.

  6. 76 FR 27250 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal...

    Science.gov (United States)

    2011-05-11

    ...The Commander, Fifth Coast Guard District, has issued a temporary deviation from the regulations governing the operation of the SR170 Centerville Turnpike Bridge across the Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal, mile 15.2, at Chesapeake, VA. The deviation is necessary to facilitate urgent mechanical structural repairs to the swing span. Under this deviation, the......

  7. 33 CFR 110.70 - Chesapeake and Delaware Canal, easterly of Courthouse Point, Md.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Chesapeake and Delaware Canal, easterly of Courthouse Point, Md. 110.70 Section 110.70 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Special Anchorage Areas § 110.70 Chesapeake and Delaware Canal, easterly of...

  8. 78 FR 23488 - Drawbridge Operation Regulations; Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal...

    Science.gov (United States)

    2013-04-19

    ...The Coast Guard has issued a temporary deviation from the operating schedule that governs the SR 170 Centerville Turnpike Bridge, across the Atlantic Intracoastal Waterway, mile 15.2, Albemarle and Chesapeake Canal, at Chesapeake, VA. The deviation is necessary to facilitate structural repairs to the superstructure of the SR 170 Centerville Turnpike Draw Bridge. This temporary deviation will......

  9. 76 FR 70349 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal...

    Science.gov (United States)

    2011-11-14

    ...The Commander, Fifth Coast Guard District, has issued a temporary deviation from the regulations governing the operation of the S168 Bridge across the Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal, mile 12.0, at Chesapeake (Great Bridge), VA. This deviation is necessary to accommodate the annual Christmas parade...

  10. 75 FR 16004 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal...

    Science.gov (United States)

    2010-03-31

    ...The Commander, Fifth Coast Guard District, has issued a temporary deviation from the regulations governing the operation of the SR170 Centerville Turnpike Bridge across the Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal, mile 15.7, at Chesapeake, VA. The deviation is necessary to facilitate structural repairs to the swing span. This deviation allows the drawbridge to remain in......

  11. 78 FR 67938 - Drawbridge Operation Regulation; Atlantic Intracoastal Waterway, Albemarle and Chesapeake Canal...

    Science.gov (United States)

    2013-11-13

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOMELAND..., Albemarle and Chesapeake Canal, Chesapeake, VA AGENCY: Coast Guard, DHS. ACTION: Notice of deviation from... caters to a variety of vessels from tug and barge traffic to recreational vessels traveling from...

  12. 76 FR 52691 - Captain John Smith Chesapeake National Historic Trail Advisory Council

    Science.gov (United States)

    2011-08-23

    ... National Park Service Captain John Smith Chesapeake National Historic Trail Advisory Council AGENCY... Captain John Smith Chesapeake National Historic Trail will hold a meeting. Designated through an amendment..., Maryland, Delaware, and in the District of Columbia,'' tracing the 1607-1609 voyages of Captain John...

  13. 76 FR 26767 - Captain John Smith Chesapeake National Historic Trail Advisory Council

    Science.gov (United States)

    2011-05-09

    ... National Park Service Captain John Smith Chesapeake National Historic Trail Advisory Council AGENCY... Captain John Smith Chesapeake National Historic Trail will hold a meeting. Designated through an amendment..., Maryland, Delaware, and in the District of Columbia,'' tracing the 1607-1609 voyages of Captain John...

  14. 77 FR 12324 - Captain John Smith Chesapeake National Historic Trail Advisory Council

    Science.gov (United States)

    2012-02-29

    ... National Park Service Captain John Smith Chesapeake National Historic Trail Advisory Council AGENCY... Captain John Smith Chesapeake National Historic Trail will hold a meeting. Designated through an amendment..., Maryland, Delaware, and in the District of Columbia,'' tracing the 1607-1609 voyages of Captain John...

  15. Management case study: Tampa Bay, Florida

    Science.gov (United States)

    Morrison, G.; Greening, H.S.; Yates, K.K.

    2012-01-01

    Tampa Bay, Florida,USA, is a shallow,subtropical estuary that experienced severe cultural eutrophication between the 1940s and 1980s, a period when the human population of its watershed quadrupled. In response, citizen action led to the formation of a public- and private-sector partnership (the Tampa Bay Estuary Program), which adopted a number of management objectives to support the restoration and protection of the bay’s living resources. These included numeric chlorophyll a and water-clarity targets, as well as long-term goals addressing the spatial extent of sea grasses and other selected habitat types, to support estuarine-dependent faunal guilds.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

    Roberts-Ashby, Tina; Brandon N. Ashby,

    2016-01-01

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

  18. F00294: NOS Hydrographic Survey , Lower Chesapeake Bay, Virginia, 1987-03-03

    Data.gov (United States)

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

  19. F00300: NOS Hydrographic Survey , Lower Chesapeake Bay, Virginia, 1987-07-09

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  1. Identifying Fossil Shell Resources via Geophysical Surveys: Chesapeake Bay Region, Virginia

    Science.gov (United States)

    2016-05-01

    must be tuned from site to site. Ultimately, it is recommended that a combination of geologic digitizing and quantitative assessment be used to...Beach. ................................... 34 Figure 32. Digitized vs. quantitative interpretations of buried FOS locations at Tyler’s Beach...geologist or geophysicist with extensive experience analyzing the seismic data line by line and hand digitizing the reflection data as needed. This

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  6. H12786: NOS Hydrographic Survey , Central Chesapeake Bay, 2015-10-07

    Data.gov (United States)

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

  7. F00454: NOS Hydrographic Survey , Upper Chesapeake Bay, Maryland, 1999-09-14

    Data.gov (United States)

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

  8. H11918: NOS Hydrographic Survey , Central Chesapeake Bay, 2010-05-05

    Data.gov (United States)

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

  9. Chesapeake Bay Low Freshwater Inflow Study. Biota Assessment. Phase I. Volume I.

    Science.gov (United States)

    1980-08-01

    Mneiiopsis (Mille.r 1979, Cargo and Schultz * 1967). MAY O.J - I 0.2- 1 0.2 r’ II I VBII 02 U. ,a- -_ ,., --.. MARC H 0 0.1 I’ t. JAH V pfodu. t 9011 c-e...Peters and Kjelson (1975), who looked at menhaden, spot, pinfish, and southern flounder. Chao and Musick (1977) examined food habitat of ten juvenile...Report. U.S. Department of Commerce. NOAA/NMFS. Chambers, J.R., J.A. Musick , and J. Davis. 1976. "Methods of Distinguishing Larval Aelwife from Larval

  10. H10652: NOS Hydrographic Survey , Northern Chesapeake Bay, Maryland, 1997-08-11

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  12. H10703: NOS Hydrographic Survey , Northern Chesapeake Bay, Maryland, 1998-03-25

    Data.gov (United States)

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

  13. H10752: NOS Hydrographic Survey , Northern Chesapeake Bay, Maryland, 1997-11-11

    Data.gov (United States)

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

  14. F00438: NOS Hydrographic Survey , Northern Chesapeake Bay - Baltimore Harbor, Maryland, 1998-05-20

    Data.gov (United States)

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

  15. H10934: NOS Hydrographic Survey , Upper Chesapeake Bay, Maryland, 2000-06-12

    Data.gov (United States)

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

  16. H10691: NOS Hydrographic Survey , Northern Chesapeake Bay, Maryland, 1996-11-06

    Data.gov (United States)

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

  17. H10745: NOS Hydrographic Survey , Chesapeake Bay, Nautilis Shoal, Virginia, 1997-05-14

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  2. 77 FR 35266 - Special Local Regulation for Marine Events, Chesapeake Bay Workboat Race, Back River, Messick...

    Science.gov (United States)

    2012-06-13

    ....C. 553(d)(3), the Coast Guard finds that good cause exists for making this rule effective less than... the event site to view the competition. To provide for the safety of participants, spectators, support... portion of certain waterways during specified times, the effect of this regulation will not be...

  3. H06360: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1938-09-28

    Data.gov (United States)

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

  4. THE RELATIONSHIP OF FLORAL COMPOSITION AND PRIMARY PRODUCTIVITY IN CHESAPEAKE BAY. (R828677C002)

    Science.gov (United States)

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

  5. 76 FR 27967 - Safety Zone; Shore Thing and Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Science.gov (United States)

    2011-05-13

    ... View Beach Park, Norfolk, VA in support of the Shore Thing and Independence Day Fireworks event. This action is necessary to provide for the safety of life on navigable waters during the Shore Thing and... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Shore Thing and Independence Day...

  6. 75 FR 26155 - Safety Zone; Shore Thing & Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Science.gov (United States)

    2010-05-11

    ... View Beach Park, Norfolk, VA in support of the Shore Thing & Independence Day Fireworks event. This... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Shore Thing & Independence Day Fireworks... Federal Register (73 FR 3316). Public Meeting We do not now plan to hold a public meeting. But you...

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

    Data.gov (United States)

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

  8. H05197: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1932-12-31

    Data.gov (United States)

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

  9. H06364: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1938-08-20

    Data.gov (United States)

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

  10. H07003: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1944-11-19

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  12. Geological survey of Maryland using EREP flight data. [mining, mapping, Chesapeake Bay islands, coastal water features

    Science.gov (United States)

    Weaver, K. N. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Underflight photography has been used in the Baltimore County mined land inventory to determine areas of disturbed land where surface mining of sand and ground clay, or stone has taken place. Both active and abandoned pits and quarries were located. Aircraft data has been used to update cultural features of Calvert, Caroline, St. Mary's, Somerset, Talbot, and Wicomico Counties. Islands have been located and catalogued for comparison with older film and map data for erosion data. Strip mined areas are being mapped to obtain total area disturbed to aid in future mining and reclamation problems. Coastal estuarine and Atlantic Coast features are being studied to determine nearshore bedforms, sedimentary, and erosional patterns, and manmade influence on natural systems.

  13. 76 FR 4345 - A Method To Assess Climate-Relevant Decisions: Application in the Chesapeake Bay

    Science.gov (United States)

    2011-01-25

    ...: Environmental Protection Agency (EPA). ACTION: Notice of Peer Review Workshop. SUMMARY: EPA is announcing that Eastern Research Group, Inc. (ERG), an EPA contractor for external scientific peer review, will convene an independent panel of experts and organize and conduct an external peer review workshop to review the...

  14. H11603: NOS Hydrographic Survey , Lower Chesapeake Bay, Virginia, 2007-09-13

    Data.gov (United States)

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

  15. H06598: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1940-10-04

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  17. H11323: NOS Hydrographic Survey , Approaches to Chesapeake Bay, Virginia, 2006-06-21

    Data.gov (United States)

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

  18. H12575: NOS Hydrographic Survey , Approaches to Chesapeake Bay, 2013-07-30

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  20. 75 FR 17683 - Cooperative Conservation Partnership Initiative-Chesapeake Bay Watershed

    Science.gov (United States)

    2010-04-07

    ... must be sent the proposal for review. By mail: Gregory K. Johnson, Director, Financial Assistance... participants to implement conservation practices and enhancements, including the development and adoption of... must provide a narrative proposal following the requirements set forth in this notice. All...

  1. RECONNAISSANCE FOR ARSENIC, ESTRADIOL, ANTIBIOTICS, AND MICROBIAL RESISTANCE IN POULTRY-DOMINATED CHESAPEAKE BAY WATERSHEDS

    Science.gov (United States)

    There are concerns about the effects from the high density of poultry feeding operations and the extensive use of feed amendments on water quality in the Shenandoah Valley in Virginia and Delmarva Peninsula. Therefore, we conducted reconnaissance investigations in two Shenandoah ...

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  5. Annotated Bibliography of the Lower Chesapeake Bay: Current Literature of Biological, Chemical, Geological and Physical Studies.

    Science.gov (United States)

    1984-01-31

    OTIC USERS Unclassified 22a NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Inlude Area Code) 122c. OFFICE SYMBOL Craig L. Seltzer (804) 441-3767/827...llth Middle-Atlantic Regional Meeting. Washington, D. C. No Annotation Citation Colo 41 CHEM:organics Huggett, R. J.; Bender , M. E. (1980) Kepone in...tables, plots and site locations. Citation C058 ~58 CHEM:heavy metals Bender , M. E.; Huggett, R. J. (1977) The effect of Tropical Storm Agnes on heavy

  6. 3 CFR 13508 - Executive Order 13508 of May 12, 2009. Chesapeake Bay Protection and Restoration

    Science.gov (United States)

    2010-01-01

    ... performance oriented and publicly accountable; (d) apply innovative and cost-effective pollution control... citizen organizations. Sec. 302. Elements of EPA Reports. The strategies and actions identified by the... structures at sea, such as cases of force majeure caused by stress of weather or other act of God. PART...

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

    Data.gov (United States)

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

  8. D00129: NOS Hydrographic Survey , Chesapeake Bay, Nautilus Shoal, Virginia, 1998-09-18

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  12. H11016: NOS Hydrographic Survey , Chesapeake Bay, Virginia, 2000-11-09

    Data.gov (United States)

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

  13. F00305: NOS Hydrographic Survey , Chesapeake Bay, Maryland and Virginia, 1987-09-14

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  15. F00307: NOS Hydrographic Survey , Chesapeake Bay, Maryland and Virginia, 1987-11-20

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  18. F00259: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 1984-05-22

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  2. F00304: NOS Hydrographic Survey , Chesapeake Bay, Maryland and Virginia, 1987-08-14

    Data.gov (United States)

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

  3. H11529: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2006-10-16

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  6. H12045: NOS Hydrographic Survey , Southern Chesapeake Bay, Virginia, 2009-12-14

    Data.gov (United States)

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

  7. The Chesapeake Bay crater: geology and geophysics of a Late Eocene submarine impact structure

    Science.gov (United States)

    Poag, C. Wylie; Koeberl, Christian; Reimold, Wolf Uwe

    2004-01-01

    The list of impact craters documented on Earth is short. Only about 165 genuine impact structures have been identified to date (Table 1.1). Even so, the number is steadily increasing at the rate of ∼3–5 per year (Grieve et al. 1995; Earth Impact Database at http://www.unb.ca/passc/Impact/Database/). In stark contrast, most other rocky planets and satellites of our solar system are pockmarked by thousands to hundreds of thousands of impact features (Beatty et al. 1999). Nevertheless, impact specialists acknowledge that Earth, too, has undergone billions of years of bolide bombardment (Melosh 1989; Schoenberg et al. 2002). The most intense bombardment, however, took place during Earth’s earliest history (∼3.8–4 Ga; Ryder 1990; Cohen et al. 2000; Ryder et al. 2000). Traces of most terrestrial impacts have been completely erased or strongly altered by the dynamic processes of a thick atmosphere, deep ocean, and mobile crust, a combination unique to our planet. Planetary geologists now recognize that processes associated with bolide impacts are fundamental to planetary accretion and surface modification (Melosh 1989; Peucker-Ehrenbrink and Schmitz 2001). Incoming meteorites may have been primary sources for Earth’s water, and, perhaps, even organic life as we know it (Thomas et al. 1997; Kring 2000). There is little doubt that impacts played a major role in the evolution of Earth’s biota (Ryder et al. 1996; Hart 1996).

  8. H08078: NOS Hydrographic Survey , Chesapeake Bay, Virginia, 1953-07-20

    Data.gov (United States)

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

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

    Science.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  13. 75 FR 78667 - Cooperative Conservation Partnership Initiative-Chesapeake Bay Watershed

    Science.gov (United States)

    2010-12-16

    ..., energy conservation, mitigating the effects of climate change, facilitating climate change adaptation, or... tribes, State and local units of government, producer associations, farmer cooperatives, institutions of... partner; 2. The role of NRCS; 3. The responsibilities of the partner as it relates to the monitoring...

  14. The Seasonal Phytoplankton Assemblages Associated with the Chesapeake Bay Plume and Waters Off Dam Neck, Virginia.

    Science.gov (United States)

    1985-02-01

    indicated by A, B, C, in order of decreasing abundance. BACILLARIOPHYCEAE W S S F A Achnanthes sp. - - - x Achnanthes fimbriata (Grunow) Ross x... Achnanthes leimermann Hustedt x Actinoptychus senarius Ehrenberg x X X x Amphiprora sp. K x x Amphiprora gigantea v. sulcata (O’Meara) Cleve K x Amphora sp

  15. H06955: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1944-04-14

    Data.gov (United States)

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

  16. H06954: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1944-04-15

    Data.gov (United States)

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

  17. H06375: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1938-10-20

    Data.gov (United States)

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

  18. H11450: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 2006-08-17

    Data.gov (United States)

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

  19. H07011: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1944-12-21

    Data.gov (United States)

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

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

    Science.gov (United States)

    Wyner, Yael

    2010-01-01

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

  1. H05237: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1932-11-18

    Data.gov (United States)

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

  2. H05295: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1933-10-29

    Data.gov (United States)

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

  3. H09099: NOS Hydrographic Survey , Chesapeake Bay Sealanes, Virginia, 1969-12-18

    Data.gov (United States)

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

  4. 76 FR 63837 - Special Local Regulation for Marine Events; Chesapeake Bay Workboat Race; Back River, Messick...

    Science.gov (United States)

    2011-10-14

    .... Inclement weather forced the cancellation of the event, the sponsor did not include a make-up date in the... for the make-up date in sufficient time to allow for publication of an NPRM. Any delay encountered in... cancellation of the event, the sponsor did not include a make-up date in the original application for...

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

    Data.gov (United States)

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

  6. H06952: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1944-04-11

    Data.gov (United States)

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

  7. H10823: NOS Hydrographic Survey , Northern Chesapeake Bay - Baltimore Harbor, Maryland, 1998-11-13

    Data.gov (United States)

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

  8. 77 FR 19570 - Special Local Regulation for Marine Events, Chesapeake Bay Workboat Race, Back River, Messick...

    Science.gov (United States)

    2012-04-02

    ... economic impact of this proposed rule to be so minimal that a full Regulatory Evaluation is unnecessary... area will be in effect and the extensive advance notifications that will be made to the maritime... races and holiday parades. For a description of the geographical area of each Coast Guard...

  9. H07010: NOS Hydrographic Survey , Chesapeake Bay, Maryland, 1944-12-20

    Data.gov (United States)

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

  10. Bayes and empirical Bayes: do they merge?

    CERN Document Server

    Petrone, Sonia; Scricciolo, Catia

    2012-01-01

    Bayesian inference is attractive for its coherence and good frequentist properties. However, it is a common experience that eliciting a honest prior may be difficult and, in practice, people often take an {\\em empirical Bayes} approach, plugging empirical estimates of the prior hyperparameters into the posterior distribution. Even if not rigorously justified, the underlying idea is that, when the sample size is large, empirical Bayes leads to "similar" inferential answers. Yet, precise mathematical results seem to be missing. In this work, we give a more rigorous justification in terms of merging of Bayes and empirical Bayes posterior distributions. We consider two notions of merging: Bayesian weak merging and frequentist merging in total variation. Since weak merging is related to consistency, we provide sufficient conditions for consistency of empirical Bayes posteriors. Also, we show that, under regularity conditions, the empirical Bayes procedure asymptotically selects the value of the hyperparameter for ...

  11. Chronic Wasting Disease Plan for the Chesapeake Marshlands National Wildlife Refuge Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan provides the Chesapeake Marshlands National Wildlife Refuge Complex with guidelines for management actions to (1) proactively reduce the risk or impact of...

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

    Data.gov (United States)

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

  13. 美国佛罗里达州坦帕湾图书馆联盟发展探析%Analysis of the USA Florida Tampa Bay Library Consortium Development

    Institute of Scientific and Technical Information of China (English)

    王宁; 孙慧明

    2015-01-01

    坦帕湾图书馆联盟是美国佛罗里达州文化教育事业的重要组成部分。它为成员馆搭建继续教育、在线研讨等方面的服务交流平台,为图书馆用户提供馆际互借、实时咨询、视频制作等多种人性化服务内容。此外,联盟的管理体制、战略规划、信息公开等方面也值得学习借鉴。%Tampa Bay Library Consortium is one of the most important cultural service organizations in Florida, United States of America. TBLC sets up a service platform including continuing education, webinars and outreach for its members. It also provides users with interlibrary loan, virtual consulting, video production and other personalized services. Besides, its management system,strategic plan and other projects are worthy of reference to our library consortia.

  14. Can Vertical Migrations of Dinoflagellates Explain Observed Bioluminescence Patterns During an Upwelling Event in Monterey Bay, California?

    Science.gov (United States)

    2012-01-25

    transect (Figure 1). The REMUS transect began near Santa Cruz in the SA, ran out to the buoy Ml (Figure 1), and then returned back to shore. Inshore...Department, California Polytechnic State University, San Luis Obispo , California, USA. ’Monterey Bay Aquarium Research Institute, Moss Landing, California...University, San Luis Obispo , CA 93407, USA. M. J. Oliver, College of Earth, Ocean and Environment, University of Delaware, 700 Pilottown Rd., Lewes, DE 19958, USA. 10 of 10

  15. Storms, channel changes, and a sediment budget for an urban-suburban stream, Difficult Run, Virginia, USA

    Science.gov (United States)

    Gellis, Allen; Myers, Michael; Noe, Gregory; Hupp, Cliff R.; Shenk, Edward; Myers, Luke

    2017-01-01

    Determining erosion and deposition rates in urban-suburban settings and how these processes are affected by large storms is important to understanding geomorphic processes in these landscapes. Sediment yields in the suburban and urban Upper Difficult Run are among the highest ever recorded in the Chesapeake Bay watershed, ranging from 161 to 376 Mg/km2/y. Erosion and deposition of streambanks, channel bed, and bars and deposition of floodplains were monitored between 1 March 2010 and 18 January 2013 in Upper Difficult Run, Virginia, USA. We documented the effects of two large storms, Tropical Storm Lee (September 2011), a 100-year event, and Super Storm Sandy (October 2012) a 5-year event, on channel erosion and deposition. Variability in erosion and deposition rates for all geomorphic features, temporally and spatially, are important conclusions of this study. Tropical Storm Lee was an erosive event, where erosion occurred on 82% of all streambanks and where 88% of streambanks that were aggrading before Tropical Storm Lee became erosional. Statistical analysis indicated that drainage area explains linear changes (cm/y) in eroding streambanks and that channel top width explains cross-sectional area changes (cm2/y) in eroding streambanks and floodplain deposition (mm/y). A quasi-sediment budget constructed for the study period using the streambanks, channel bed, channel bars, and floodplain measurements underestimated the measured suspended-sediment load by 61% (2130 Mg/y). Underestimation of the sediment load may be caused by measurement errors and to contributions from upland sediment sources, which were not measured but estimated at 36% of the gross input of sediment. Eroding streambanks contributed 42% of the gross input of sediment and accounted for 70% of the measured suspended-sediment load. Similar to other urban watersheds, the large percentage of impervious area in Difficult Run and direct runoff of precipitation leads to increased streamflow and

  16. Storms, channel changes, and a sediment budget for an urban-suburban stream, Difficult Run, Virginia, USA

    Science.gov (United States)

    Gellis, A. C.; Myers, M. K.; Noe, G. B.; Hupp, C. R.; Schenk, E. R.; Myers, L.

    2017-02-01

    Determining erosion and deposition rates in urban-suburban settings and how these processes are affected by large storms is important to understanding geomorphic processes in these landscapes. Sediment yields in the suburban and urban Upper Difficult Run are among the highest ever recorded in the Chesapeake Bay watershed, ranging from 161 to 376 Mg/km2/y. Erosion and deposition of streambanks, channel bed, and bars and deposition of floodplains were monitored between 1 March 2010 and 18 January 2013 in Upper Difficult Run, Virginia, USA. We documented the effects of two large storms, Tropical Storm Lee (September 2011), a 100-year event, and Super Storm Sandy (October 2012) a 5-year event, on channel erosion and deposition. Variability in erosion and deposition rates for all geomorphic features, temporally and spatially, are important conclusions of this study. Tropical Storm Lee was an erosive event, where erosion occurred on 82% of all streambanks and where 88% of streambanks that were aggrading before Tropical Storm Lee became erosional. Statistical analysis indicated that drainage area explains linear changes (cm/y) in eroding streambanks and that channel top width explains cross-sectional area changes (cm2/y) in eroding streambanks and floodplain deposition (mm/y). A quasi-sediment budget constructed for the study period using the streambanks, channel bed, channel bars, and floodplain measurements underestimated the measured suspended-sediment load by 61% (2130 Mg/y). Underestimation of the sediment load may be caused by measurement errors and to contributions from upland sediment sources, which were not measured but estimated at 36% of the gross input of sediment. Eroding streambanks contributed 42% of the gross input of sediment and accounted for 70% of the measured suspended-sediment load. Similar to other urban watersheds, the large percentage of impervious area in Difficult Run and direct runoff of precipitation leads to increased streamflow and

  17. CASCO BAY PLAN

    Science.gov (United States)

    Casco Bay lies at the heart of Maine's most populated area. The health of its waters, wetlands, and wildlife depend in large part on the activities of the quarter-million residents who live in its watershed. Less than 30 years ago, portions of Casco Bay were off-limits to recr...

  18. 75 FR 41520 - Chesapeake and Ohio Canal National Historical Park Advisory Commission; Notice of Public Meeting

    Science.gov (United States)

    2010-07-16

    ...Notice is hereby given that a meeting of the Chesapeake and Ohio Canal National Historical Park Advisory Commission will be held at 9 a.m., on Friday, August 13, 2010, at the Brunswick City Hall, 1 West Potomac Street, Brunswick, Maryland...

  19. 75 FR 65376 - Chesapeake and Ohio Canal National Historical Park Advisory Commission; Notice of Public Meeting

    Science.gov (United States)

    2010-10-22

    ...Notice is hereby given that a meeting of the Chesapeake and Ohio Canal National Historical Park Advisory Commission will be held at 9:30 a.m., on Friday, November 5, 2010, at Rockwood Manor Park, 11001 MacArthur Boulevard, Potomac, Maryland...

  20. 75 FR 80526 - Chesapeake and Ohio Canal National Historical Park Advisory Commission; Notice of Public Meeting

    Science.gov (United States)

    2010-12-22

    ...Notice is hereby given that a meeting of the Chesapeake and Ohio Canal National Historical Park Advisory Commission will be held at 9:30 a.m., on Friday, January 7, 2011, at C & O Canal National Historical Park, 1850 Dual Highway, Suite 100, Hagerstown, Maryland...

  1. 75 FR 17158 - Chesapeake and Ohio Canal National Historical Park Advisory Commission; Notice of Public Meeting

    Science.gov (United States)

    2010-04-05

    ...Notice is hereby given that a meeting of the Chesapeake and Ohio Canal National Historical Park Advisory Commission (the Commission) will be held at 9 a.m., on Friday, May 14, 2010, at the House of Sweden, 2900 K Street, NW., Washington, DC...

  2. 75 FR 4844 - Chesapeake and Ohio Canal National Historical Park Advisory Commission; Notice of Public Meeting

    Science.gov (United States)

    2010-01-29

    ...Notice is hereby given that a meeting of the Chesapeake and Ohio Canal National Historical Park Advisory Commission will be held at 9 a.m., on Friday, February 12, 2010, at the House of Sweden, 2900 K Street, NW., Washington, DC...

  3. Delft Delta Design: The Houston Galveston Bay Region, Texas, USA

    NARCIS (Netherlands)

    Kothuis, B.L.M.; Brand, A.D.; Sebastian, A.G.; Nillesen, A.L.; Jonkman, S.N.

    2015-01-01

    In 2008, Hurricane Ike devastated Bolivar Peninsula, narrowly missing the more heavily industrialized and populated areas in the region. In the aftermath of the hurricane, the Severe Storm Prediction, Education and Evacuation from Disasters (SSPEED) Center at Rice University in Houston, and Texas A&

  4. Hammond Bay Biological Station

    Data.gov (United States)

    Federal Laboratory Consortium — Hammond Bay Biological Station (HBBS), located near Millersburg, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). HBBS was established by...

  5. Bathymetry in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 4x4 meter resolution bathymetric surface for Jobos Bay, Puerto Rico (in NAD83 UTM 19 North). The depth values are in meters referenced to the...

  6. Biscayne Bay Alongshore Epifauna

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Field studies to characterize the alongshore epifauna (shrimp, crabs, echinoderms, and small fishes) along the western shore of southern Biscayne Bay were started in...

  7. Humboldt Bay Orthoimages

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set consists of 0.5-meter pixel resolution, four band orthoimages covering the Humboldt Bay area. An orthoimage is remotely sensed image data in which...

  8. eBay.com

    DEFF Research Database (Denmark)

    Engholm, Ida

    2014-01-01

    Celebrated as one of the leading and most valuable brands in the world, eBay has acquired iconic status on par with century-old brands such as Coca-Cola and Disney. The eBay logo is now synonymous with the world’s leading online auction website, and its design is associated with the company......’s purpose: selling millions of goods, some of which are ‘designer’ items and some of which are considered design icons....

  9. Evaluation of nutria (Myocastor coypus) detection methods in Maryland, USA

    Science.gov (United States)

    Pepper, Margaret A; Herrmann, Valentine; Hines, James; Nichols, James; Kendrot, Stephen R

    2017-01-01

    Nutria (Myocaster coypus), invasive, semi-aquatic rodents native to South America, were introduced into Maryland near Blackwater National Wildlife Refuge (BNWR) in 1943. Irruptive population growth, expansion, and destructive feeding habits resulted in the destruction of thousands of acres of emergent marshes at and surrounding BNWR. In 2002, a partnership of federal, state and private entities initiated an eradication campaign to protect remaining wetlands from further damage and facilitate the restoration of coastal wetlands throughout the Chesapeake Bay region. Program staff removed nearly 14,000 nutria from five infested watersheds in a systematic trapping and hunting program between 2002 and 2014. As part of ongoing surveillance activities, the Chesapeake Bay Nutria Eradication Project uses a variety of tools to detect and remove nutria. Project staff developed a floating raft, or monitoring platform, to determine site occupancy. These platforms are placed along waterways and checked periodically for evidence of nutria visitation. We evaluated the effectiveness of monitoring platforms and three associated detection methods: hair snares, presence of scat, and trail cameras. Our objectives were to (1) determine if platform placement on land or water influenced nutria visitation rates, (2) determine if the presence of hair snares influenced visitation rates, and (3) determine method-specific detection probabilities. Our analyses indicated that platforms placed on land were 1.5–3.0 times more likely to be visited than those placed in water and that platforms without snares were an estimated 1.7–3.7 times more likely to be visited than those with snares. Although the presence of snares appears to have discouraged visitation, seasonal variation may confound interpretation of these results. Scat was the least effective method of determining nutria visitation, while hair snares were as effective as cameras. Estimated detection probabilities provided by occupancy

  10. Det sorte USA

    DEFF Research Database (Denmark)

    Brøndal, Jørn

    Bogen gennemgår det sorte USAs historie fra 1776 til 2016, idet grundtemaet er spændingsforholdet mellem USAs grundlæggelsesidealer og den racemæssige praksis, et spændingsforhold som Gunnar Myrdal kaldte "det amerikanske dilemma." Bogen, der er opbygget som politisk, social og racemæssig historie...

  11. Glemmer USA Afghanistan nu?

    DEFF Research Database (Denmark)

    Jakobsen, Peter Viggo

    2015-01-01

    Hvis Obamas efterfølger kan skrue den rigtige strategiske fortælling sammen så vil USA ikke forlade Afghanistan med udgangen af 2016.......Hvis Obamas efterfølger kan skrue den rigtige strategiske fortælling sammen så vil USA ikke forlade Afghanistan med udgangen af 2016....

  12. Module bay with directed flow

    Science.gov (United States)

    Torczynski, John R.

    2001-02-27

    A module bay requires less cleanroom airflow. A shaped gas inlet passage can allow cleanroom air into the module bay with flow velocity preferentially directed toward contaminant rich portions of a processing module in the module bay. Preferential gas flow direction can more efficiently purge contaminants from appropriate portions of the module bay, allowing a reduced cleanroom air flow rate for contaminant removal. A shelf extending from an air inlet slit in one wall of a module bay can direct air flowing therethrough toward contaminant-rich portions of the module bay, such as a junction between a lid and base of a processing module.

  13. 33 CFR 100.124 - Maggie Fischer Memorial Great South Bay Cross Bay Swim, Great South Bay, New York.

    Science.gov (United States)

    2010-07-01

    ... South Bay Cross Bay Swim, Great South Bay, New York. 100.124 Section 100.124 Navigation and Navigable... NAVIGABLE WATERS § 100.124 Maggie Fischer Memorial Great South Bay Cross Bay Swim, Great South Bay, New York... swimmer or safety craft on the swim event race course bounded by the following points: Starting Point...

  14. Identification of largemouth bass virus in the introduced Northern snakehead inhabiting the Cheasapeake Bay watershed

    Science.gov (United States)

    Iwanowicz, Luke R.; Densmore, Christine L.; Hahn, Cassidy M.; McAllister, Phillip; Odenkirk, John

    2013-01-01

    The Northern Snakehead Channa argus is an introduced species that now inhabits the Chesapeake Bay. During a preliminary survey for introduced pathogens possibly harbored by these fish in Virginia waters, a filterable agent was isolated from five specimens that produced cytopathic effects in BF-2 cells. Based on PCR amplification and partial sequencing of the major capsid protein (MCP), DNA polymerase (DNApol), and DNA methyltransferase (Mtase) genes, the isolates were identified as Largemouth Bass virus (LMBV). Nucleotide sequences of the MCP (492 bp) and DNApol (419 pb) genes were 100% identical to those of LMBV. The nucleotide sequence of the Mtase (206 bp) gene was 99.5% identical to that of LMBV, and the single nucleotide substitution did not lead to a predicted amino acid coding change. This is the first report of LMBV from the Northern Snakehead, and provides evidence that noncentrarchid fishes may be susceptible to this virus.

  15. Organochlorine contaminant exposure and effects in pipping black-crowned night-herons in Delaware Bay

    Science.gov (United States)

    Rattner, B.A.; Hoffman, D.J.; Melancon, M.J.; Olsen, G.H.; Parsons, K.C.; Schmidt, S.R.

    1998-01-01

    Pea Patch Island in Delaware Bay is the site of the largest heronry north of Florida. From 1989-93. the population of 9 species of wading birds numbered approximately 12,000 pairs. but has recently declined to 7,000 pairs. Because Delaware Bay is a major shipping channel. and receives anthropogenic releases of toxic substances from agricultural, industrial and municipal point and nonpoint sources, contaminant exposure and effects to the heronry have been an ongoing concern. In 1997, piping black-crowned night-herons (BCNHs) wee collected from separate nests at Pea Patch Island (N=l5), and from a coastal reference site, Middle Island (N=9), in Rehoboth Bay. DE. There was neither evidence of malformations nor hepatic histopathological lesions, and body and liver weights did not differ between sites. Biomarkers of petroleum hydrocarbons, polyhalogenated contaminant and metal exposure (cytochrome P450 induction and oxidative stress responses) did not differ (P>0.05) between sites, however, activities of benzyloxy- and ethoxyresorufin-O-dealkylase were greater in 3 of 15 embryos from Pea Patch Island compared to Middle Island. Concentrations of 21 organochlorine pesticides and metabolites were relatively low at both sites. with p,.p'DDE values well below the threshold associated with eggshell thinning. Although total PCB concentration was modestly elevated (Pdioxins, dibenzofurans and Toxic Equivalents were low and did not differ between sites. Surprisingly, organochlorine contaminant exposure and effects in Delaware Bay BCNHs appear to be considerably less than that observed and recently reported (ETC 16:2315-2322,1997) for herons residing in the Chesapeake Bay.

  16. USA Hire Testing Platform

    Data.gov (United States)

    Office of Personnel Management — The USA Hire Testing Platform delivers tests used in hiring for positions in the Federal Government. To safeguard the integrity of the hiring processes and ensure...

  17. Loeng USA Sisejulgeolekuministeeriumi kantslerilt

    Index Scriptorium Estoniae

    2005-01-01

    13. okt. pidas USA Sisejulgeolekuministeeriumi teaduse ja tehnoloogia kantsler dr Charles McQueary Tartu Ülikooli Tehnoloogiainstituudis loengu "Uue põlvkonna ettevõtlust suunavad ja julgeolekut edendavad tehnoloogiad"

  18. USA kunstidessant Venemaale

    Index Scriptorium Estoniae

    2007-01-01

    USA kunstnike näitus "Kolm sajandit ameerika kunsti" Moskvas Pushkini muuseumis. Eksponeeritakse Mark Rothko, Jean-Michel Basguiat', Roy Lichtensteini, Robert Rauschenbergi, Georgia O'Keefe'i, Willem de Kooningi töid

  19. The Fermi's Bayes Theorem

    CERN Document Server

    D'Agostini, G

    2005-01-01

    It is curious to learn that Enrico Fermi knew how to base probabilistic inference on Bayes theorem, and that some influential notes on statistics for physicists stem from what the author calls elsewhere, but never in these notes, {\\it the Bayes Theorem of Fermi}. The fact is curious because the large majority of living physicists, educated in the second half of last century -- a kind of middle age in the statistical reasoning -- never heard of Bayes theorem during their studies, though they have been constantly using an intuitive reasoning quite Bayesian in spirit. This paper is based on recollections and notes by Jay Orear and on Gauss' ``Theoria motus corporum coelestium'', being the {\\it Princeps mathematicorum} remembered by Orear as source of Fermi's Bayesian reasoning.

  20. Applying Integrated ITS Technologies to Parking Management Systems: A Transit-Based Case Study in the San Francisco Bay Area

    OpenAIRE

    Shaheen, Susan; Rodier, Caroline J.; Eaken, Amanda M.

    2004-01-01

    California Partners for Advanced Transit and Highways has teamed with the California Department of Transportation, the Bay Area Rapid Transit (BART) District, ParkingCarmaâ„¢, and Quixote Corporation to launch a smart parking research demonstration at the Rockridge BART station in the East San Francisco Bay Area (California, USA). The results of an extensive literature review demonstrate that different smart parking applications implemented worldwide can ease traveler delays, increase transit...

  1. Controls on residence time and exchange in a system of shallow coastal bays

    Science.gov (United States)

    Safak, I.; Wiberg, P. L.; Richardson, D. L.; Kurum, M. O.

    2015-04-01

    Patterns of transport and residence time influence the morphology, ecology and biogeochemistry of shallow coastal bay systems in important ways. To better understand the factors controlling residence time and exchange in coastal bays, a three-dimensional finite-volume coastal ocean model was set up and validated with field observations of circulation in a system of 14 shallow coastal bays on the Atlantic coast of the USA (Virginia Coast Reserve). Residence times of neutrally buoyant particles as well as exchange among the bays in the system and between the bays and the ocean were examined with Lagrangian particle tracking. There was orders of magnitude variation in the calculated residence time within most of the bays, ranging from hours in the tidally refreshed (repletion) water near the inlets to days-weeks in the remaining (residual) water away from the inlets. Residence time in the repletion waters was most sensitive to the tidal phase (low vs. high) when particles were released whereas residence time in the residual waters was more sensitive to wind forcing. Wind forcing was found to act as a diffuser that shortens particle residence within the bays; its effect was higher away from the inlets and in relatively confined bays. Median residence time in the bays significantly decreased with an increase in the ratio between open water area and total area (open water plus marsh). Exchange among the bays and capture areas of inlets (i.e., exchange between the bays and the ocean) varied considerably but were insensitive to tidal phase of release, wind, and forcing conditions in different years, in contrast to the sensitivity of residence time to these factors. We defined a new quantity, termed shortest-path residence time, calculated as distance from the closest inlet divided by root-mean-square velocity at each point in model domain. A relationship between shortest-path residence time and particle-tracking residence time provides a means of estimating residence time

  2. 33 CFR 165.501 - Chesapeake Bay entrance and Hampton Roads, VA and adjacent waters-Regulated Navigation Area.

    Science.gov (United States)

    2010-07-01

    ... release), that is underway within two nautical miles of the CBBT or the I-664 Bridge Tunnel shall station... Port. (6) Requirements for navigation charts, radars, and pilots. No vessel over 100 gross tons may enter the Regulated Navigation Area, unless it has on board: (i) Corrected charts of the...

  3. 2002 Sediment Grab Data for Catlett and Goodwin Islands on the York River, Chesapeake Bay, Virginia (Ches_2002sedgrabs)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the sediment grain size gathered from grab sampling in 2002 (56 stations).In Fall/Winter 2002, researchers from the Virginia Institute of...

  4. Biogeochemical and Hydrological Controls on Mercury and Methylmercury in First Order Coastal Plain Watersheds of the Chesapeake Bay

    Science.gov (United States)

    Heyes, A.; Gilmour, C. C.; Bell, J. T.; Butera, D.; McBurney, A. W.

    2015-12-01

    Over the past 7 years we made use of the long-term research site at the Smithsonian Environmental Research Center (SERC) in central Maryland to study the fluxes of mercury (Hg) and methylmercury (MeHg) in three small first-order mid-Atlantic coastal plain watersheds. One watershed is entirely forested, one watershed is primarily agriculture with a forested stream buffer, and one watershed is mixed land use but contains a beaver produced wetland pond. Our initial goals were to assess watershed Hg yields in the mid-Atlantic and to establish a baseline prior to implementation of Hg emissions controls. All three studied watersheds produced relatively high yields of Hg, with the greatest yield coming from the forested watershed. Our initial evaluation of three watersheds showed that MeHg production and flux could also be high, but varied dramatically among watersheds and across years and seasons. During each year we observed episodic MeHg production in the spring and sometimes during prolonged high-flow storm events in the fall. The observed spring maxima of MeHg release coincided with development of anoxia in riparian groundwater. MeHg accumulation in riparian groundwater began once nitrate was depleted and either iron accumulation or sulfate depletion of groundwater began. We propose the presence of nitrate was modulating MeHg production through the suppression of sulfate and iron reducers and perhaps methanogens. As sulfate is not limiting in any of the watersheds owing to the sediments marine origin, we hypothesize the depletion of nitrate allows sulfate reducing bacteria to now utilize available carbon. Although wetlands are generally thought of as the primary zones of MeHg production in watersheds, shallow riparian groundwaters very close to the stream appear to play that role in SERC Coastal Plain watersheds. We hypothesize that the balance between nitrate, sulfate and other microbial electron acceptors in watersheds is a major control on MeHg production. Land management practices that change upset this balance by changing nitrate load and carbon quality will undoubtedly impact the cycling of Hg.

  5. 75 FR 62358 - Stakeholder Input on Stormwater Rulemaking Related to the Chesapeake Bay; Notice of Public Meeting

    Science.gov (United States)

    2010-10-08

    ...-62362] [FR Doc No: 2010-25318] ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 122 [FRL-9211-2] Stakeholder... strengthen its stormwater program. A range of public and private stakeholders provided input through both... livability. EPA is working with all stakeholders to strengthen its stormwater program and support...

  6. Evidence of eelgrass (Zostera marina) seed dispersal by northern diamondback terrapin (Malaclemys terrapin terrapin) in lower Chesapeake Bay.

    Science.gov (United States)

    Tulipani, Diane C; Lipcius, Romuald N

    2014-01-01

    The initial discovery in May 2009 of eelgrass (Zostera marina) seeds in fecal samples of wild-caught northern diamondback terrapins (Malaclemys terrapin terrapin) was the first field evidence of eelgrass seed ingestion in this species. This finding suggested the potential of terrapins as seed dispersers in eelgrass beds, which we sampled for two additional years (2010 and 2011). Seeds were only found in feces of terrapins captured prior to June 8 in all three years, coinciding with eelgrass seed maturation and release. Numbers of seeds in terrapin feces varied annually and decreased greatly in 2011 after an eelgrass die off in late 2010. The condition of seeds in terrapin feces was viable-mature, germinated, damaged, or immature. Of terrapins captured during time of seed release, 97% were males and juvenile females, both of which had head widths seeds was 33% for males, 35% for small females, and only 6% for large (mature) females. Probability of seed ingestion decreased exponentially with increasing terrapin head width; only males and small females (head width seed dispersal. The characteristic that diamondback terrapins have well-defined home ranges allowed us to estimate the number of terrapins potentially dispersing eelgrass seeds annually. In seagrass beds of the Goodwin Islands region (lower York River, Virginia), there were 559 to 799 terrapins, which could disperse between 1,341 and 1,677 eelgrass seeds annually. These would represent a small proportion of total seed production within a single seagrass bed. However, based on probable home range distances, terrapins can easily traverse eelgrass meadow boundaries, thereby dispersing seeds beyond the bed of origin. Given the relatively short dispersion distance of eelgrass seeds, the diamondback terrapin may be a major source of inter-bed seed dispersal and genetic diversity.

  7. Chesapeake Bay Protection and Restoration: Improvements and Lessons Learned at Craney Island and Southgate Annex, Norfolk, Virginia

    Science.gov (United States)

    2011-05-01

    Bioretention Regional pond Grass Channels Dry swale Level spreader Soils compost amendments Wet swale Underground detention Vegetated Roofs Filtering...micro scale) 15 48 24 8 95 8 8 / 28 $ 43,500 04-SM-1 Dry swale (or bioretention if enough head) 35 33 14 11 93 9 9 / 28 $ 90,800 01-SM-2...filter strip 22 28 17 14 81 22 / 85 $21,500 27-SM-2 Flow to open space/filter strip 22 28 17 14 81 22 / 85 $31,500 35-SM-4 Bioretention 17 28 25 11

  8. 2003 Sediment Grab Data for Catlett and Goodwin Islands on the York River, Chesapeake Bay, Virginia (Ches_2003sedgrabs)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the sediment grain size gathered from grab sampling in 2003 (24 stations).In Fall/Winter 2002, researchers from the Virginia Institute of...

  9. 2004 Benthic Grab Data for Catlett and Goodwin Islands on the York River in Chesapeake Bay, Virginia (Ches_2004benthos)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the benthic community information gathered from grab sampling in 2004 (12 stations). In Fall/Winter 2002, researchers from the Virginia...

  10. 2002 Benthic Grab Data for Catlett and Goodwin Islands on the York River in Chesapeake Bay, Virginia (Ches_2002benthos)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the benthic community information gathered from grab sampling in 2002 (56 stations).In Fall/Winter 2002, researchers from the Virginia...

  11. 2003 Benthic Grab Data for Catlett and Goodwin Islands on the York River in Chesapeake Bay, Virginia (Ches_2003benthos)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the benthic community information gathered from grab sampling in 2003 (24 stations). In Fall/Winter 2002, researchers from the Virginia...

  12. Invasive Species Guidebook for Department of Defense Installations in the Chesapeake Bay Watershed: Identification, Control, and Restoration

    Science.gov (United States)

    2007-11-01

    floor and prevent growth of other vegetation. It is especially detrimental to native spring wildflowers and their related organisms. Fig buttercup’s...an aggressive, perennial pest of waterways from coastal Virginia to Florida and west to Texas, with a disjunct population in California . It...Invasive Plant Atlas of New England, University of California -Davis database, and Washington State Department of Ecology. 102 INVASIVE SPECIES

  13. Use of a chiA probe for detection of chitinase genes in bacteria from the Chesapeake Bay

    Digital Repository Service at National Institute of Oceanography (India)

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

    PCR primers specific for the chiA gene were designed by alignment and selection of highly conserved regions of chiA sequences from Serratia marcescens, Alteromonas sp., Bacillus circulans and Aeromonas caviae. These primers were used to amplify a...

  14. GENETIC DIVERSITY OF VIBRIO CHOLERAE IN CHESAPEAKE BAY DETERMINED BY AMPLIFIED FRAGMENT LENGTH POLYMORPHISM FINGERPRINTING. (R824995)

    Science.gov (United States)

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

  15. nowCOAST's Map Service for NOAA NOS Chesapeake Bay Operational Forecast System (CBOFS) Forecast Guidance (Time Offsets)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Map Information: This nowCOAST time-offsets map service provides maps of the latest nowcasts and forecast guidance of water temperature, salinity, water currents,...

  16. WATERSHED LAND USE INFLUENCES NUTRIENT CONCENTRATIONS OF PHRAGMITES AUSTRALIS LEAVES IN SUBESTUARIES OF CHESAPEAKE BAY. (R828684C001)

    Science.gov (United States)

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

  17. 2004 Sediment Grab Data for Catlett and Goodwin Islands on the York River, Chesapeake Bay, Virginia (Ches_2004sedgrabs)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set represents the sediment grain size gathered from grab sampling in 2004 (12 stations). In Fall/Winter 2002, researchers from the Virginia Institute of...

  18. nowCOAST's Map Service for NOAA NOS Chesapeake Bay Operational Forecast System (CBOFS) Forecast Guidance (Time Enabled)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Map Information: This nowCOAST time-enabled map service provides maps of the latest nowcasts and forecast guidance of water temperature, salinity, water currents,...

  19. 33 CFR 207.160 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Science.gov (United States)

    2010-07-01

    ..., bridges, piers, fences, trees, houses, shops or any other property of the United States pertaining to the..., house boats or like craft shall be expedited by locking them through with commercial craft (other than... by written permit from the District Engineer. (8) The building, assembling, or breaking up of a...

  20. Baltimaade kunsti turnee USAs

    Index Scriptorium Estoniae

    1998-01-01

    5. nov.-st USA Lõuna-Carolina osariigis Wellington B. Grey galeriis ja Jenkins Fine Art Center's 13 eesti, läti ja leedu kunstniku näitus, mis hakkab kolme aasta jooksul ringlema Ameerikas. Eksponeeritud fotokunst, video, installatsioon, joonistused. Kuraator Peeter Linnap ja Mari Laanemets peavad ettekande näituse avamisega samal ajal toimuval Fotohariduse Ühingu konverentsil

  1. Remarks on kernel Bayes' rule

    OpenAIRE

    Johno, Hisashi; Nakamoto, Kazunori; Saigo, Tatsuhiko

    2015-01-01

    Kernel Bayes' rule has been proposed as a nonparametric kernel-based method to realize Bayesian inference in reproducing kernel Hilbert spaces. However, we demonstrate both theoretically and experimentally that the prediction result by kernel Bayes' rule is in some cases unnatural. We consider that this phenomenon is in part due to the fact that the assumptions in kernel Bayes' rule do not hold in general.

  2. BCDC Bay Trail Alignment 2009

    Data.gov (United States)

    California Department of Resources — The Bay Trail provides easily accessible recreational opportunities for outdoor enthusiasts, including hikers, joggers, bicyclists and skaters. It also offers a...

  3. Bioinvasion in a Brazilian bay: filling gaps in the knowledge of southwestern Atlantic biota.

    Directory of Open Access Journals (Sweden)

    Barbara L Ignacio

    Full Text Available BACKGROUND: Biological invasions are a major cause of global species change. Nevertheless, knowledge about the distribution and ecology of introduced species is regionally biased, and many gaps in knowledge exist for most developing countries. METHODOLOGY/PRINCIPAL FINDINGS: To study the zoobenthos on the hard substratum of the Ilha Grande Bay, a survey was conducted on both natural and artificial substrata at three depths and seven sites. The species recorded were classified as native, cryptogenic or introduced. Multivariate analyses were conducted to assess the prevalence of introduced species in these communities and to compare the distribution of species on natural and artificial substrata of this bay to identify possible discrepancies in habitat use. Of the 61 species, 25 were cryptogenic, 10 were introduced and 26 were native. Similar numbers of introduced species were found on both natural and artificial substrata, though the community composition was significantly different between them. We also compared the species composition of the Ilha Grande Bay survey to other inventories taken around the world. The highest similarities were found between the Ilha Grande Bay inventory and the Atlantic coastal region (Tampa Bay, USA and the Gulf of Mexico, American Samoa and Pearl Harbor (USA inventories. CONCLUSIONS/SIGNIFICANCE: This study presents the first published comprehensive list of hard substratum sessile marine invertebrate species in a Brazilian bay. The high percentage of cryptogenic species reveals gaps in both zoological records and information on introduced species for the Brazilian coast. The introduced species successfully colonized different sites in the Ilha Grande Bay, including both natural and artificial substrata. In addition, we find that artificial structures may not be good surrogates for natural rocky shores and may represent an ecological threat. Comparisons with other inventories suggest a history of broad

  4. Management case study: Tampa Bay, Florida

    Science.gov (United States)

    Morrison, Gerold; Greening, Holly; Yates, Kimberly K.; Wolanski, Eric; McLusky, Donald S.

    2011-01-01

    Tampa Bay, Florida, USA, is a shallow, subtropical estuary that experienced severe cultural eutrophication between the 1940s and 1980s, a period when the human population of its watershed quadrupled. In response, citizen action led to the formation of a public- and private-sector partnership (the Tampa Bay Estuary Program), which adopted a number of management objectives to support the restoration and protection of the bay’s living resources. These included numeric chlorophyll a and water-clarity targets, as well as long-term goals addressing the spatial extent of seagrasses and other selected habitat types, to support estuarine-dependent faunal guilds. Over the past three decades, nitrogen controls involving sources such as wastewater treatment plants, stormwater conveyance systems, fertilizer manufacturing and shipping operations, and power plants have been undertaken to meet these and other management objectives. Cumulatively, these controls have resulted in a 60% reduction in annual total nitrogen (TN) loads relative to earlier worse-case (latter 1970s) conditions. As a result, annual water-clarity and chlorophyll a targets are currently met in most years, and seagrass cover measured in 2008 was the highest recorded since 1950. Factors that have contributed to the observed improvements in Tampa Bay over the past several decades include the following: (1) Development of numeric, science-based water-quality targets to meet a long-term goal of restoring seagrass acreage to 1950s levels. Empirical and mechanistic models found that annual average chlorophyll a concentrations were a primary manageable factor affecting light attenuation. The models also quantified relationships between TN loads, chlorophyll a concentrations, light attenuation, and fluctuations in seagrass cover. The availability of long-term monitoring data, and a systematic process for using the data to evaluate the effectiveness of management actions, has allowed managers to track progress and

  5. USA-USSR protocol

    CERN Multimedia

    1970-01-01

    On 30 November the USA Atomic Energy Commission and the USSR State Committee for the Utilization of Atomic Energy signed, in Washington, a protocol 'on carrying out of joint projects in the field of high energy physics at the accelerators of the National Accelerator Laboratory (Batavia) and the Institute for High Energy Physics (Serpukhov)'. The protocol will be in force for five years and can be extended by mutual agreement.

  6. The sediment budget of an urban coastal lagoon (Jamaica Bay, NY) determined using 234Th and 210Pb

    Science.gov (United States)

    Renfro, Alisha A.; Cochran, J. Kirk; Hirschberg, David J.; Bokuniewicz, Henry J.; Goodbred, Steven L.

    2016-10-01

    The sediment budget of Jamaica Bay (New York, USA) has been determined using the natural particle-reactive radionuclides 234Th and 210Pb. Inventories of excess thorium-234 (234Thxs, half-life = 24.1 d) were measured in bottom sediments of the Bay during four cruises from September 2004 to July 2006. The mean bay-wide inventory for the four sampling periods ranged from 3.5 to 5.0 dpm cm-2, four to six times that expected from 234Th production in the overlying water column. The presence of dissolved 234Th and a high specific activity of 234Thxs on particles at the bay inlet (∼30 dpm g-1) indicated that both dissolved and particulate 234Th could be imported into the bay from the ocean. Based on these observations, a mass balance of 234Th yields an annual input of ∼39 ± 14 × 1010 g sediment into the bay. Mass accumulation rates determined from profiles of excess 210Pb (half-life = 22.3 y) in sediment cores require annual sediment import of 7.4 ± 4.5 × 1010 g. Both radionuclides indicate that there is considerable marine-derived sediment import to Jamaica Bay, consistent with earlier work using 210Pb. Such sediment input may be important in sustaining longer-term accretion rates of salt marshes in the bay.

  7. The Bayes Inference Engine

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, K.M.; Cunningham, G.S.

    1996-04-01

    The authors are developing a computer application, called the Bayes Inference Engine, to provide the means to make inferences about models of physical reality within a Bayesian framework. The construction of complex nonlinear models is achieved by a fully object-oriented design. The models are represented by a data-flow diagram that may be manipulated by the analyst through a graphical programming environment. Maximum a posteriori solutions are achieved using a general, gradient-based optimization algorithm. The application incorporates a new technique of estimating and visualizing the uncertainties in specific aspects of the model.

  8. 75 FR 29891 - Special Local Regulation; Maggie Fischer Memorial Great South Bay Cross Bay Swim, Great South Bay...

    Science.gov (United States)

    2010-05-28

    ... Swim, Great South Bay, NY, in the Federal Register (74 FR 32428). We did not receive any comments or... published at 74 FR 32428 on July 8, 2009, is adopted as a final rule with the following changes: PART 100... South Bay Cross Bay Swim, Great South Bay, NY AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY:...

  9. Bayes Multiple Decision Functions

    CERN Document Server

    Wu, Wensong

    2011-01-01

    This paper deals with the problem of simultaneously making many (M) binary decisions based on one realization of a random data matrix X. M is typically large and X will usually have M rows associated with each of the M decisions to make, but for each row the data may be low dimensional. A Bayesian decision-theoretic approach for this problem is implemented with the overall loss function being a cost-weighted linear combination of Type I and Type II loss functions. The class of loss functions considered allows for the use of the false discovery rate (FDR), false nondiscovery rate (FNR), and missed discovery rate (MDR) in assessing the decision. Through this Bayesian paradigm, the Bayes multiple decision function (BMDF) is derived and an efficient algorithm to obtain the optimal Bayes action is described. In contrast to many works in the literature where the rows of the matrix X are assumed to be stochastically independent, we allow in this paper a dependent data structure with the associations obtained through...

  10. Water physics and chemistry data from bottle casts from the CHESAPEAKE L/S and other platforms from 28 November 1955 to 31 December 1956 (NODC Accession 6800101)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water physics and chemistry data were collected from bottle casts from the CHESAPEAKE L/S and other platforms from 28 November 1955 to 31 December 1956. Data were...

  11. Bayes multiple decision functions.

    Science.gov (United States)

    Wu, Wensong; Peña, Edsel A

    2013-01-01

    This paper deals with the problem of simultaneously making many (M) binary decisions based on one realization of a random data matrix X. M is typically large and X will usually have M rows associated with each of the M decisions to make, but for each row the data may be low dimensional. Such problems arise in many practical areas such as the biological and medical sciences, where the available dataset is from microarrays or other high-throughput technology and with the goal being to decide which among of many genes are relevant with respect to some phenotype of interest; in the engineering and reliability sciences; in astronomy; in education; and in business. A Bayesian decision-theoretic approach to this problem is implemented with the overall loss function being a cost-weighted linear combination of Type I and Type II loss functions. The class of loss functions considered allows for use of the false discovery rate (FDR), false nondiscovery rate (FNR), and missed discovery rate (MDR) in assessing the quality of decision. Through this Bayesian paradigm, the Bayes multiple decision function (BMDF) is derived and an efficient algorithm to obtain the optimal Bayes action is described. In contrast to many works in the literature where the rows of the matrix X are assumed to be stochastically independent, we allow a dependent data structure with the associations obtained through a class of frailty-induced Archimedean copulas. In particular, non-Gaussian dependent data structure, which is typical with failure-time data, can be entertained. The numerical implementation of the determination of the Bayes optimal action is facilitated through sequential Monte Carlo techniques. The theory developed could also be extended to the problem of multiple hypotheses testing, multiple classification and prediction, and high-dimensional variable selection. The proposed procedure is illustrated for the simple versus simple hypotheses setting and for the composite hypotheses setting

  12. USGS Tampa Bay Pilot Study

    Science.gov (United States)

    Yates, K.K.; Cronin, T. M.; Crane, M.; Hansen, M.; Nayeghandi, A.; Swarzenski, P.; Edgar, T.; Brooks, G.R.; Suthard, B.; Hine, A.; Locker, S.; Willard, D.A.; Hastings, D.; Flower, B.; Hollander, D.; Larson, R.A.; Smith, K.

    2007-01-01

    Many of the nation's estuaries have been environmentally stressed since the turn of the 20th century and will continue to be impacted in the future. Tampa Bay, one the Gulf of Mexico's largest estuaries, exemplifies the threats that our estuaries face (EPA Report 2001, Tampa Bay Estuary Program-Comprehensive Conservation and Management Plan (TBEP-CCMP)). More than 2 million people live in the Tampa Bay watershed, and the population constitutes to grow. Demand for freshwater resources, conversion of undeveloped areas to resident and industrial uses, increases in storm-water runoff, and increased air pollution from urban and industrial sources are some of the known human activities that impact Tampa Bay. Beginning on 2001, additional anthropogenic modifications began in Tampa Bat including construction of an underwater gas pipeline and a desalinization plant, expansion of existing ports, and increased freshwater withdrawal from three major tributaries to the bay. In January of 2001, the Tampa Bay Estuary Program (TBEP) and its partners identifies a critical need for participation from the U.S. Geological Survey (USGS) in providing multidisciplinary expertise and a regional-scale, integrated science approach to address complex scientific research issue and critical scientific information gaps that are necessary for continued restoration and preservation of Tampa Bay. Tampa Bay stakeholders identified several critical science gaps for which USGS expertise was needed (Yates et al. 2001). These critical science gaps fall under four topical categories (or system components): 1) water and sediment quality, 2) hydrodynamics, 3) geology and geomorphology, and 4) ecosystem structure and function. Scientists and resource managers participating in Tampa Bay studies recognize that it is no longer sufficient to simply examine each of these estuarine system components individually, Rather, the interrelation among system components must be understood to develop conceptual and

  13. Island Bay Wilderness study area : Island Bay National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a brief report on a wilderness study area located in the Island Bay National Wildlife Refuge. It discusses the history of the study area, its...

  14. Tšarterkool USA-s / Johannes Kiersch

    Index Scriptorium Estoniae

    Kiersch, Johannes

    2001-01-01

    24.-27. mainì 01 toimub Tallinnas EFFE 2001 (European Forum of Freedom in Education) konverents "Haridus tänases kodanikuühiskonnas." Konverentsil esineb ka Witteni Waldorf-pedagoogika Instituudi õppejõud Johannes Kiersch. Lähemalt tema artiklist USA-s populaarsust võitvate tsharterkoolide kohta, mis on riigi- ja erakooli vahevorm

  15. Lavaca Bay 1985-1987

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Samples were collected from October 15, 1985 through June 12, 1987 in emergent marsh and non-vegetated habitats throughout the Lavaca Bay system to characterize...

  16. Back Bay Wilderness area description

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a description of the lands located within the Back Bay National Wildlife Refuge. Within these lands, it designates which area is suitable for...

  17. Annual report, Bristol Bay, 1955

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Commercial fishery management activities for Bristol Bay for 1955, including lists of operators, extensive statistics, descriptions of enforcement activities, and...

  18. FL BAY SPECTROUT-DIET

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Juvenile spotted seatrout and other sportfish are being monitored annually over a 6-mo period in Florida Bay to assess their abundance over time relative to...

  19. Annual report, Bristol Bay, 1958

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Commercial fishery management activities for Bristol Bay for 1958, including lists of operators, extensive statistics, and descriptions of enforcement activities.

  20. Vapor Intrusion Facilities - South Bay

    Data.gov (United States)

    U.S. Environmental Protection Agency — POINT locations for the South Bay Vapor Instrusion Sites were derived from the NPL data for Region 9. One site, Philips Semiconductor, was extracted from the...

  1. TTÜ ja TÜ osalevad USA armee miljoniprojektides

    Index Scriptorium Estoniae

    2016-01-01

    TTÜ ja TÜ liitusid USA-s tegutseva meditsiinitehnoloogia ettevõtete konsortsiumiga. Nii jõuavad juhtivate Eesti kõrgkoolide teadmised USA armeesse, kes konsortsiumi kaudu innovaatilisi tooteid ja teenuseid sisse ostab

  2. Euroopa teadis USA salavanglaist / Tõnis Erilaid

    Index Scriptorium Estoniae

    Erilaid, Tõnis, 1943-

    2005-01-01

    USA endise välisministri Colin Powelli sõnul pole see tema sõpradele Euroopas uudiseks, et USA on viinud vange riikidesse, kus tema seadused ei kehti. USA praeguse välisministri Condoleezza Rice'i sõnul on USA vange üle kuulanud väljaspool USA-d. USA Today kirjeldab Stare Kiejkuty küla Poolas, kus arvatavasti on olnud salavangla

  3. An evaluation of a professional development course for secondary school science teachers: Chesapeake Watershed Ecology

    Science.gov (United States)

    Wood, Barbara Bonsall

    1997-12-01

    Concern about the quality of schools has grown to the point that it has become a national goal to improve education in the United States. Science education in particular has been under attack. Improvement requires not only changes in science content, but also in instructional approach. Implicit in this reform is an equally substantive change in professional development practice because too many science teachers are unprepared to meet these challenges. Unfortunately, courses to instruct secondary science teachers both in research techniques and instructional strategies are rare. Chesapeake Watershed Ecology, a professional development course, was created to meet this need. The course was evaluated within the framework of Stake's Countenance Model, using an objectives-based approach liberally embedded with qualitative methods. Research questions and findings focused on congruence between what was intended to occur and what was actually observed to occur before, during, and after instruction. Specifically, this formative study judged the effectiveness of the course at providing secondary science teachers with realistic research skills and strategies for the high school classroom. Research questions focused on 10 program features: teacher background, appropriate curriculum, resource availability, teacher participation, course choreography, classroom interactions, improved performance, teacher attitudes, intent of the teachers to use course activities in their own classrooms, and unexpected outcomes. Because nine of the ten features well exceeded criterion standards, the course was deemed effective and worthy of adoption. The findings of the evaluation led to four major implications beyond the course: (1) The Stake Model was an effective assessment tool that may be useful in other professional development course evaluations. (2) Chesapeake Watershed Ecology was an effective model for conceptual integration of scientific disciplines with pedagogical methods. (3

  4. Sea-Level Rise Implications for Coastal Protection from Southern Mediterranean to the U.S.A. Atlantic Coast

    Science.gov (United States)

    Ismail, Nabil; Williams, Jeffress

    2013-04-01

    demonstrated in autumn 2010 when the storm Becky reached the Santander Bay, Spain. As reported by THESEUS, the FP-7 EU project (2009-2013), the peak of nearshore significant wave height was about 8 m, the storm surge reached 0.6 m, with tidal level of 90% of the tidal range. The latest storm in December 2010, which hit the Nile Delta and which was the severest in the last decades showed that generated surges, up to 1.0 m as well as a maximum of 7.5 m wave height in the offshore of Alexandria presented a major natural hazard in coastal zones in terms of wave run up and overtopping. Along the US Atlantic Coast, where Hurricane Sandy this autumn and Hurricane Irene in 2011 left chaos in their wakes, a perfect storm of rising sea levels and dense coastal development at high risk . Super storm Sandy sent a storm surge of 4-5 m onto New Jersey's and New York's fragile barrier island and urban shorelines, causing an estimated 70 billion (USD) in damages and widespread misery for coastal inhabitants. Sea Level Rise and Impact on Upgrade of Coastal Structures: Williams (2013) highlights in his recent paper that adaptation planning on national scales in the USA for projected sea-level rise of 0.5-2 m by A.D. 2100 is advisable. Further he points out that sea-level rise, as a major driving force of change for coastal regions, is becoming increasingly important as a hazard to humans and urban areas in the coastal zone worldwide as global climate change takes effect. During the 20th century, sea level began rising at a global average rate of 1.7 mm/yr (). The current average rise rate is 3.1 mm/yr, a 50% increase over the past two decades. Many regions are experiencing even greater rise rates due to local geophysical (e.g., Louisiana, Chesapeake Bay) and oceanographic (mid-Atlantic coast) forces. Further the Mississippi River Delta plain region of Louisiana has much higher than average rates of LRSL rise due to geologic factors such as subsidence and man-made alterations to the delta plain

  5. Pepeljajev eesti näitlejatega USA-s

    Index Scriptorium Estoniae

    2008-01-01

    Sasha Pepeljajevi tantsulavastust "Uksed" etendati USA rahvusvahelisel teatrifestivalil "Arts & Ideas". Vene-Eesti trupi Apparatus lavastus on pühendatud Daniil Harmsi 100. sünniaastapäevale ning põhineb tema töödel

  6. 77 FR 18739 - Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2012-03-28

    ... the January 17, 2008, issue of the Federal Register (73 FR 3316). Public Meeting We do not now plan to... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA... is intended to restrict vessels from a portion of the Presque Island Bay during the Bay Swim...

  7. 77 FR 35860 - Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2012-06-15

    ..., Erie, PA in the Federal Register (77 FR 18739). We received no letters commenting on the proposed rule... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bay Swim V, Presque Isle Bay, Erie, PA... restrict vessels from a portion of the Presque Island Bay during the Bay Swim V swimming event. The...

  8. 78 FR 34575 - Safety Zone; Bay Swim VI, Presque Isle Bay, Erie, PA

    Science.gov (United States)

    2013-06-10

    ... FR Federal Register NPRM Notice of Proposed Rulemaking TFR Temporary Final Rule A. Regulatory History... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Bay Swim VI, Presque Isle Bay, Erie, PA... portion of Presque Isle bay during the Bay Swim VI swimming event. This temporary safety zone is...

  9. DESICCATION IS A LIMITING FACTOR FOR EELGRASS (ZOSTERA MARINA L.) DISTRIBUTION IN THE INTERTIDAL ZONE OF A NORTHEASTERN P{ACIFIC (USA) ESTUARY

    Science.gov (United States)

    Intertidal irradiance, temperature, and aerial exposure were measured for two years in intertidal Zostera marina beds located in Yaquina Bay (Newport, OR, USA). These physical data were correlated with plant growth and other metrics measured at intervals during the study. Pho...

  10. SF Bay Water Quality Improvement Fund

    Science.gov (United States)

    EPAs grant program to protect and restore San Francisco Bay. The San Francisco Bay Water Quality Improvement Fund (SFBWQIF) has invested in 58 projects along with 70 partners contributing to restore wetlands, water quality, and reduce polluted runoff.,

  11. Humboldt Bay, California Benthic Habitats 2009 Substrate

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  12. Humboldt Bay, California Benthic Habitats 2009 Geoform

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  13. Humboldt Bay, California Benthic Habitats 2009 Geodatabase

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  14. Humboldt Bay, California Benthic Habitats 2009 Biotic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Humboldt Bay is the largest estuary in California north of San Francisco Bay and represents a significant resource for the north coast region. Beginning in 2007 the...

  15. Dengue in Florida (USA

    Directory of Open Access Journals (Sweden)

    Jorge R. Rey

    2014-12-01

    Full Text Available Florida (USA, particularly the southern portion of the State, is in a precarious situation concerning arboviral diseases. The geographic location, climate, lifestyle, and the volume of travel and commerce are all conducive to arbovirus transmission. During the last decades, imported dengue cases have been regularly recorded in Florida, and the recent re-emergence of dengue as a major public health concern in the Americas has been accompanied by a steady increase in the number of imported cases. In 2009, there were 28 cases of locally transmitted dengue in Key West, and in 2010, 65 cases were reported. Local transmission was also reported in Martin County in 2013 (29 cases, and isolated locally transmitted cases were also reported from other counties in the last five years. Dengue control and prevention in the future will require close cooperation between mosquito control and public health agencies, citizens, community and government agencies, and medical professionals to reduce populations of the vectors and to condition citizens and visitors to take personal protection measures that minimize bites by infected mosquitoes.

  16. USA pelgab Hiina tehnoloogialuuret / Tõnis Arnover

    Index Scriptorium Estoniae

    Arnover, Tõnis, 1952-

    2005-01-01

    Hiina Ameerika-vastasest majandusluurest. USA luureameti andmetel on USA-s loodud üle kolme tuhande Hiina firma, kelle ülesandeks on tööstusliku või sõjalise tehnoloogia hankimine. Vt. samas: Hiina firmad ostavad üha suuremaid USA ettevõtteid

  17. Bayes linear statistics, theory & methods

    CERN Document Server

    Goldstein, Michael

    2007-01-01

    Bayesian methods combine information available from data with any prior information available from expert knowledge. The Bayes linear approach follows this path, offering a quantitative structure for expressing beliefs, and systematic methods for adjusting these beliefs, given observational data. The methodology differs from the full Bayesian methodology in that it establishes simpler approaches to belief specification and analysis based around expectation judgements. Bayes Linear Statistics presents an authoritative account of this approach, explaining the foundations, theory, methodology, and practicalities of this important field. The text provides a thorough coverage of Bayes linear analysis, from the development of the basic language to the collection of algebraic results needed for efficient implementation, with detailed practical examples. The book covers:The importance of partial prior specifications for complex problems where it is difficult to supply a meaningful full prior probability specification...

  18. 33 CFR 117.622 - West Bay

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false West Bay 117.622 Section 117.622 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.622 West Bay The draw of the West Bay Bridge, mile...

  19. Bayes' postulate for trinomial trials

    Science.gov (United States)

    Diniz, M. A.; Polpo, A.

    2012-10-01

    In this paper, we discuss Bayes' postulate and its interpretation. We extend the binomial trial method proposed by de Finetti [1] to trinomial trials, for which we argue that the consideration of equiprobability a priori for the possible outcomes of the trinomial trials implies that the parameter vector has Dirichlet(1,1) as prior. Based on this result, we agree with Stigler [2] in that the notion in Bayes' postulate stating "absolutely know nothing" is related to the possible outcomes of an experiment and not to "non-information" about the parameter.

  20. FrogwatchUSA

    Science.gov (United States)

    Droege, S.

    2002-01-01

    full text: Frogs and toads are perhaps the most approachable and available of all our wildlife. In many, if not most places, they are abundant. In wetter parts of the East, almost anyone outside on a warm rainy night in spring will hear their dream-like calls, bellows, trills and snores. Even in the deserts of the Southwest, a nocturnal trip after a summer monsoon will yield toads moving across the roads toward a cacophonous orgy of mating and calling in the roadside ditches and desert pools. Birds share with frogs and toads this same sense of presence in our daily lives. But the difference is that birds are like the attractive neighbor who just never gives you the time of day, while frogs are more like the troglodyte who appears regularly to chat, philosophize, and have a beer. Uninvited, frogs appear in our water gardens, toads are on our stoops in the morning, we catch them when we are kids, raise their babies in the aquarium, and feel sorry when we find we have run them over with the lawnmower. When concerns about declining populations of amphibians reached the mass media, the Secretaries' office became involved. In addition to using traditional research mechanisms to investigate the problem, the Secretary also wanted to involve the public directly. The combination of high public appeal and the relative ease with which frog calls can be learned made a large-scale monitoring program for frogs and toads possible. What emerged was a program called Frogwatch USA, modeled after a successful Canadian program with a similar name. A web site was created (www.frogwatch.org) that presented potential frogwatchers with directions and a way to register their site online as well as enter their data. Observers chose where to count frogs depending on what they felt was important. For some it was their backyard, others chose vulnerable wetlands in their neighborhoods, or spots on local refuges and parks. Initially funded at $8,000 a year and then after two years increased to