Science.gov

Sample records for chesapeake bay impact

  1. The Chesapeake Bay impact structure

    USGS Publications Warehouse

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

    2015-10-28

    About 35 million years ago, during late Eocene time, a 2-mile-wide asteroid or comet smashed into Earth in what is now the lower Chesapeake Bay in Virginia. The oceanic impact vaporized, melted, fractured, and (or) displaced the target 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. Models suggest that even up to 50 miles away the velocity of the intensely hot air blast was greater than 1,500 miles per hour, and ground shaking was equivalent to an earthquake greater than magnitude 8.0 on the Richter scale. Large tsunamis affected most of the North Atlantic basin. The Chesapeake Bay impact structure is among the 20 largest known impact structures on Earth.

  2. Hydrocode Simulations of the Chesapeake Bay Impact

    NASA Technical Reports Server (NTRS)

    Collins, G. S.; Melosh, H. J.

    2004-01-01

    The Chesapeake Bay Impact Crater (CBIC) formed about 35 million years ago (late Eocene), in a shallow marine environment (400-600 m water depth). The crater is complex and developed in a multi-layer, rheologically-variable target that comprised 400-1000 meters of soft, water-saturated sediments overlying crystalline basement. Seismic reflection data illustrates that the Chesapeake Bay crater morphology - often described as an "inverted sombrero" - is similar to other marine-target impact craters. It consists of a approx. 1 - 1.5-km deep, highly disturbed central crater, surrounded by a shallower, less deformed basin. The inner crater has a diameter of approx. 40 km; the edge of the outer basin extends to 85-km diameter. The morphological divide between the inner and outer crater is termed the inner ring or peak ring. Little is known about the nature of the inner ring. Seismic reflection data show that the underlying basement is modestly uplifted; however, it is unclear whether the pristine surface expression of the inner ring was elevated above the floor of the outer crater.

  3. Coring the Chesapeake Bay impact crater

    USGS Publications Warehouse

    Poag, C.W.

    2004-01-01

    In July 1983, the shipboard scientists of Deep Sea Drilling Project Leg 95 found an unexpected bonus in a core taken 150 kilometers east of Atlantic City, N.J. At Site 612, the scientists recovered a 10-centimeter-thick layer of late Eocene debris ejected from an impact about 36 million years ago. Microfossils and argon isotope ratios from the same layer reveal that the ejecta were part of a broad North American impact debris field, previously known primarily from the Gulf of Mexico and Caribbean Sea. Since that serendipitous beginning, years of seismic reflection profiling, gravity measurements and core drilling have confirmed the source of that strewn field - the Chesapeake Bay impact crater, the largest structure of its kind in the United States, and the sixth-largest impact crater on Earth.

  4. Potential climate-change impacts on the Chesapeake Bay

    Treesearch

    Raymond G. Najjar; Christopher R. Pyke; Mary Beth Adams; Denise Breitburg; Carl Hershner; Michael Kemp; Robert Howarth; Margaret R. Mulholland; Michael Paolisso; David Secor; Kevin Sellner; Denice Wardrop; Robert. Wood

    2010-01-01

    We review current understanding of the potential impact of climate change on the Chesapeake Bay. Scenarios for CO2 emissions indicate that by the end of the 21st century the Bay region will experience significant changes in climate forcings with respect to historical conditions, including increases in CO2 concentrations,...

  5. Potential climate-change impacts on the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Najjar, R.; Pyke, C.; Adams, M.; Breitburg, D.; Hershner, C.; Kemp, M.; Howarth, R.; Mulholland, M.; Paolisso, M.; Secor, D.; Sellner, K.; Wardrop, D.; Wood, R.

    2008-12-01

    We review current understanding of the potential impact of climate change on the Chesapeake Bay. Scenarios for carbon dioxide emissions indicate that by the end of the 21st century the Bay region will experience significant changes in climate forcings with respect to historic conditions, including increases in carbon dioxide concentrations, sea level, and water temperature of 50-160 percent, 0.7-1.6 m, and 2-6 K, respectively. Also likely are increases in precipitation amount (particularly in the winter and spring), precipitation intensity, intensity of tropical and extratropical cyclones (though their frequency may decrease), and sea-level variability. The greatest uncertainty is associated with changes in annual streamflow, though it is likely that winter and spring flows will increase. Climate change alone will cause the Bay to function very differently in the future. Likely changes include: (1) an increase in coastal flooding and submergence of estuarine wetlands; (2) an increase in salinity variability on many time scales; (3) an increase in harmful algae; (4) an increase in hypoxia; (5) a reduction of eelgrass, the dominant submerged aquatic vegetation in the Bay; and (6) altered interactions among trophic levels, with warm-water fish and shellfish species ultimately being favored in the Bay. The magnitude of these changes is sensitive to the carbon dioxide emission trajectory, so that actions taken now to reduce carbon dioxide emissions will reduce climate impacts on the Bay. Research needs include improved precipitation and streamflow projections for the Bay watershed and whole-system monitoring and modeling (supplemented by process studies) that can capture the likely non-linear responses of the Chesapeake Bay system to climate variability and change.

  6. Potential climate-change impacts on the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Najjar, Raymond G.; Pyke, Christopher R.; Adams, Mary Beth; Breitburg, Denise; Hershner, Carl; Kemp, Michael; Howarth, Robert; Mulholland, Margaret R.; Paolisso, Michael; Secor, David; Sellner, Kevin; Wardrop, Denice; Wood, Robert

    2010-01-01

    We review current understanding of the potential impact of climate change on the Chesapeake Bay. Scenarios for CO 2 emissions indicate that by the end of the 21 st century the Bay region will experience significant changes in climate forcings with respect to historical conditions, including increases in CO 2 concentrations, sea level, and water temperature of 50-160%, 0.7-1.6 m, and 2-6 °C, respectively. Also likely are increases in precipitation amount (very likely in the winter and spring), precipitation intensity, intensity of tropical and extratropical cyclones (though their frequency may decrease), and sea-level variability. The greatest uncertainty is associated with changes in annual streamflow, though it is likely that winter and spring flows will increase. Climate change alone will cause the Bay to function very differently in the future. Likely changes include: (1) an increase in coastal flooding and submergence of estuarine wetlands; (2) an increase in salinity variability on many time scales; (3) an increase in harmful algae; (4) an increase in hypoxia; (5) a reduction of eelgrass, the dominant submerged aquatic vegetation in the Bay; and (6) altered interactions among trophic levels, with subtropical fish and shellfish species ultimately being favored in the Bay. The magnitude of these changes is sensitive to the CO 2 emission trajectory, so that actions taken now to reduce CO 2 emissions will reduce climate impacts on the Bay. Research needs include improved precipitation and streamflow projections for the Bay watershed and whole-system monitoring, modeling, and process studies that can capture the likely non-linear responses of the Chesapeake Bay system to climate variability, climate change, and their interaction with other anthropogenic stressors.

  7. Chesapeake Bay TMDL Document

    EPA Pesticide Factsheets

    This page provides the Total Maximum Daily Load (TMDL) report for the Chesapeake Bay. It includes the executive summary, main report, and appendices. The Chesapeake Bay TMDL was established by U.S. EPA Region 3 on December 29, 2010

  8. Deep drilling into the Chesapeake Bay impact structure

    USGS Publications Warehouse

    Gohn, G.S.; Koeberl, C.; Miller, K.G.; Reimold, W.U.; Browning, J.V.; Cockell, C.S.; Horton, J.W.; Kenkmann, T.; Kulpecz, A.A.; Powars, D.S.; Sanford, W.E.; Voytek, M.A.

    2008-01-01

    Samples from a 1.76-kilometer-deep corehole drilled near the center of the late Eocene Chesapeake Bay impact structure (Virginia, USA) reveal its geologic, hydrologic, and biologic history. We conducted stratigraphic and petrologic analyses of the cores to elucidate the timing and results of impact-melt creation and distribution, transient-cavity collapse, and ocean-water resurge. Comparison of post-impact sedimentary sequences inside and outside the structure indicates that compaction of the crater fill influenced long-term sedimentation patterns in the mid-Atlantic region. Salty connate water of the target remains in the crater fill today, where it poses a potential threat to the regional groundwater resource. Observed depth variations in microbial abundance indicate a complex history of impact-related thermal sterilization and habitat modification, and subsequent post-impact repopulation.

  9. Deep drilling into the Chesapeake Bay impact structure.

    PubMed

    Gohn, G S; Koeberl, C; Miller, K G; Reimold, W U; Browning, J V; Cockell, C S; Horton, J W; Kenkmann, T; Kulpecz, A A; Powars, D S; Sanford, W E; Voytek, M A

    2008-06-27

    Samples from a 1.76-kilometer-deep corehole drilled near the center of the late Eocene Chesapeake Bay impact structure (Virginia, USA) reveal its geologic, hydrologic, and biologic history. We conducted stratigraphic and petrologic analyses of the cores to elucidate the timing and results of impact-melt creation and distribution, transient-cavity collapse, and ocean-water resurge. Comparison of post-impact sedimentary sequences inside and outside the structure indicates that compaction of the crater fill influenced long-term sedimentation patterns in the mid-Atlantic region. Salty connate water of the target remains in the crater fill today, where it poses a potential threat to the regional groundwater resource. Observed depth variations in microbial abundance indicate a complex history of impact-related thermal sterilization and habitat modification, and subsequent post-impact repopulation.

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

    USGS Publications Warehouse

    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

  11. Gravity investigations of the Chesapeake Bay impact structure

    USGS Publications Warehouse

    Plescia, J.B.; Daniels, D.L.; Shah, A.K.

    2009-01-01

    The Chesapeake Bay impact structure is a complex impact crater, ??85 km in diameter, buried beneath postimpact sediments. Its main structural elements include a central uplift of crystalline bedrock, a surrounding inner crater filled with impact debris, and an annular faulted margin composed of block-faulted sediments. The gravity anomaly is consistent with that of a complex impact consisting of a central positive anomaly over the central uplift and an annular negative anomaly over the inner crater. An anomaly is not recognized as being associated with the faulted margin or the outer edge of the structure. Densities from the Eyreville drill core and modeling indicate a density contrast of ??0.3-0.6 g cm-3 between crystalline basement and the material that fills the inner crater (e.g., Exmore breccia and suevite). This density contrast is somewhat higher than for other impact structures, but it is a function of the manner in which the crater fill was deposited (as a marine resurge deposit). Modeling of the gravity data is consistent with a depth to basement of ??1600 m at the site of Eyreville drill hole and 800 m at the central uplift. Both depths are greater than the depth at which crystalline rocks were encountered in the cores, suggesting that the cored material is highly fractured para-allochthonous rock. ?? 2009 The Geological Society of America.

  12. Chesapeake Bay Crater, Virginia: Confirmation of Impact Origin

    NASA Astrophysics Data System (ADS)

    Koeberl, C.; Reimold, W. U.; Brandt, D.; Poag, C. W.

    1995-09-01

    Poag et al. [1] identified a late Eocene boulder bed in drill cores from southeast Virginia, and interpreted it as an impact-generated tsunami deposit. Seismic studies and other geophysical evidence indicated the existence of a possible impact structure centered at Chesapeake Bay (37 degrees x 15' N and 76 degrees x 04' W), which may be 85-90 km in diameter [2]. Four drill cores have penetrated into the breccia, although none is available from the center of the structure, or reaches basement. A central peak-ring of crystalline rocks with about 25 km diameter is surrounded by a 30 km-wide annular trough and terrace terrane. The trough is filled with polymictic breccia composed mainly of autochthonous sedimentary clasts in a sandy matrix with some angular clasts of granitic and metasedimentary basement rocks [2]. The Chesapeake Bay crater is of special interest, because it is close to the region identified as the possible source region for the North American tektites, is of about the expected size, and has an age identical to that of the tektites [3]. While the source craters for the Central European and Ivory Coast tektite strewn fields are known, the source crater of the North American tektites has remained elusive. A variety of locations were suggested, including Popigai (Siberia), Wanapitei (Canada), Mistastin (Canada), and Bee Bluff (Texas), but all were later discounted. The distribution of the tektites and microtektites in the strewn field suggests that the North American tektite source crater is likely to be located at or near the eastern coast of the North American continent, maybe underwater [4,5]. The location of the Chesapeake Bay structure is in agreement with the area suggested before [4,5]. We have started a petrological and geochemical study of target rocks and breccias from the Chesapeake Bay structure. We analyzed the major and trace element composition of 17 mainly sedimentary samples, for comparison with North American tektite values. 14 of these

  13. Chesapeake Bay TMDL

    EPA Pesticide Factsheets

    In 2010 EPA established the Chesapeake Bay TMDL, a comprehensive pollution diet with accountability measures to restore clean water in the bay and local waters. It set limits for nutrients and sediment to meet water quality standards across the watershed

  14. Foraminiferal repopulation of the late Eocene Chesapeake Bay impact crater

    USGS Publications Warehouse

    Poag, C. Wylie

    2012-01-01

    The Chickahominy Formation is the initial postimpact deposit in the 85km-diameter Chesapeake Bay impact crater, which is centered under the town of Cape Charles, Virginia, USA. The formation comprises dominantly microfossil-rich, silty, marine clay, which accumulated during the final ~1.6myr of late Eocene time. At cored sites, the Chickahominy Formation is 16.8-93.7m thick, and fills a series of small troughs and subbasins, which subdivide the larger Chickahominy basin. Nine coreholes drilled through the Chickahominy Formation (five inside the crater, two near the crater margin, and two ~3km outside the crater) record the stratigraphic and paleoecologic succession of 301 indigenous species of benthic foraminifera, as well as associated planktonic foraminifera and bolboformids. Two hundred twenty of these benthic species are described herein, and illustrated with scanning electron photomicrographs. Absence of key planktonic foraminiferal and Bolboforma species in early Chickahominy sediments indicates that detrimental effects of the impact also disturbed the upper oceanic water column for at least 80-100kyr postimpact. After an average of ~73kyr of stressed, rapidly fluctuating paleoenvironments, which were destabilized by after-effects of the impact, most of the cored Chickahominy subbasins maintained stable, nutrient-rich, low-oxygen bottom waters and interstitial microhabitats for the remaining ~1.3myr of late Eocene time.

  15. Coesite in suevites from the Chesapeake Bay impact structure

    USGS Publications Warehouse

    Jackson, John C.; Horton, J. Wright; Chou, I-Ming; Belkin, Harvey E.

    2016-01-01

    The occurrence of coesite in suevites from the Chesapeake Bay impact structure is confirmed within a variety of textural domains in situ by Raman spectroscopy for the first time and in mechanically separated grains by X-ray diffraction. Microtextures of coesite identified in situ investigated under transmitted light and by scanning electron microscope reveal coesite as micrometer-sized grains (1–3 μm) within amorphous silica of impact-melt clasts and as submicrometer-sized grains and polycrystalline aggregates within shocked quartz grains. Coesite-bearing quartz grains are present both idiomorphically with original grain margins intact and as highly strained grains that underwent shock-produced plastic deformation. Coesite commonly occurs in plastically deformed quartz grains within domains that appear brown (toasted) in transmitted light and rarely within quartz of spheroidal texture. The coesite likely developed by a mechanism of solid-state transformation from precursor quartz. Raman spectroscopy also showed a series of unidentified peaks associated with shocked quartz grains that likely represent unidentified silica phases, possibly including a moganite-like phase that has not previously been associated with coesite.

  16. Coesite in suevites from the Chesapeake Bay impact structure

    NASA Astrophysics Data System (ADS)

    Jackson, John C.; Horton, J. Wright; Chou, I.-Ming; Belkin, Harvey E.

    2016-05-01

    The occurrence of coesite in suevites from the Chesapeake Bay impact structure is confirmed within a variety of textural domains in situ by Raman spectroscopy for the first time and in mechanically separated grains by X-ray diffraction. Microtextures of coesite identified in situ investigated under transmitted light and by scanning electron microscope reveal coesite as micrometer-sized grains (1-3 μm) within amorphous silica of impact-melt clasts and as submicrometer-sized grains and polycrystalline aggregates within shocked quartz grains. Coesite-bearing quartz grains are present both idiomorphically with original grain margins intact and as highly strained grains that underwent shock-produced plastic deformation. Coesite commonly occurs in plastically deformed quartz grains within domains that appear brown (toasted) in transmitted light and rarely within quartz of spheroidal texture. The coesite likely developed by a mechanism of solid-state transformation from precursor quartz. Raman spectroscopy also showed a series of unidentified peaks associated with shocked quartz grains that likely represent unidentified silica phases, possibly including a moganite-like phase that has not previously been associated with coesite.

  17. Chesapeake Bay study

    NASA Technical Reports Server (NTRS)

    Love, W. J.

    1972-01-01

    The objectives and scope of the Chesapeake Bay study are discussed. The physical, chemical, biological, political, and social phenomena of concern to the Chesapeake Bay area are included in the study. The construction of a model of the bay which will provide a means of accurately studying the interaction of the ecological factors is described. The application of the study by management organizations for development, enhancement, conservation, preservation, and restoration of the resources is examined.

  18. Impact of Hurricane Isabel on Hypoxia in Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Li, Y.; Li, M.

    2008-12-01

    Episodic forcing by tropical storms and hurricanes often consists of high winds, heavy precipitation, increased freshwater flow, strong vertical mixing, and intense pulses of nutrients, leading to enhanced plankton biomass and temporary relief or termination of hypoxic condition in estuaries and coastal oceans. The U.S. East and Gulf Coasts have experienced elevated tropical storm and hurricane activity in recent years, a pattern expected to persist for several more decades and that may increase due to global warming. Therefore, there is an urgent need to understand the mechanisms governing the response of a coastal ecosystem to extreme weather events. Here we present a preliminary modeling investigation into Chesapeake Bay's response to Hurricane Isabel which made landfall at the Outer Banks of North Carolina and moved past the Bay on 18 and 19 Sept 2003. Strong storm winds eroded stratification and produced strong turbulent mixing which injected bottom nutrients to the surface euphotic layer and aerated the hypoxic bottom water. After the passage of the storm, however, the horizontal salinity gradient drove restratification and return to hypoxia in bottom water as well as producing a post-storm phytoplankton bloom. Using a coupled hydrodynamic-biogeochemical model, we conduct numerical experiments to investigate how the hurricane-induced destratification and restratification cycle affects the distribution of dissolved oxygen in Chesapeake Bay and explore the mechanisms responsible for the observed rapid return of hypoxia after the storm.

  19. Impact origin of the Chesapeake Bay structure and the source of the North American tektites

    USGS Publications Warehouse

    Koeberl, C.; Poag, C.W.; Reimold, W.U.; Brandt, D.

    1996-01-01

    Seismic profiles, drill core samples, and gravity data suggest that a complex impact crater ???35.5 million years old and 90 kilometers in diameter is buried beneath the lower Chesapeake Bay. The breccia that fills the structure contains evidence of shock metamorphism, including impact melt breccias and multiple sets of planar deformation features (shock lamellae) in quartz and feldspar. The age of the crater and the composition of some breccia clasts are consistent with the Chesapeake Bay impact structure being the source of the North American tektites.

  20. Chesapeake Bay Tributary Strategies

    EPA Pesticide Factsheets

    Chesapeake Bay Tributary Strategies were developed by the seven watershed jurisdictions and outlined the river basin-specific implementation activities to reduce nutrient and sediment pollutant loads from point and nonpoint sources.

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

    NASA Astrophysics Data System (ADS)

    Levine, A. S.

    2008-03-01

    The Chesapeake Bay Impact Crater drilling provided a unique educational opportunity for the public, in particular students, and an ongoing educational partnership between USGS, NASA Langley and the other collaborators.

  2. Impact of Shoreline Stabilization Structures on Chesapeake Bay Nearshore Habitats

    NASA Astrophysics Data System (ADS)

    Palinkas, C. M.; Sanford, L. P.; Koch, E.; Stevenson, J. C.; Ortt, R.; Lorie, S.; Booth, D.

    2014-12-01

    Currently 69% of Maryland's shoreline is eroding and 12% is hardened with increasing rates of hardening occurring as development progresses. Shoreline erosion rates are likely to increase, and community needs for shoreline protection are likely to become more important as rates of sea-level rise increase with climate change, constituting a serious coastal hazard. However, the effects of different shoreline stabilization structures on erosion and nearshore water quality and habitat are complex. A variety of stabilization techniques are used in the Maryland Chesapeake Bay, and while the qualitative effects of the different techniques are generally known, there is little quantitative, long-term information available. This study has developed a comprehensive data set comparing long-term impacts of different shoreline stabilization techniques on both the physical environment and habitat. These data include shoreline and bathymetric surveys for comparison to pre-installation information, comparison of pre- and post-construction submerged aquatic vegetation (SAV) coverage, field surveys of SAV and marshes, and collection of cores to determine changes in sediment characteristics and accumulation rates. We have also assembled available estimates of wave and tides near each site to construct wave-sea level climatologies for use in a semi-empirical model of erosion potential. Statistical tests are used to explore relationships among variables. Preliminary results suggest that sediment characteristics depend on the source of material - shoreline type and estuarine salinity zone (proxy for fine sediment availability) - whereas sedimentation rate depends on structure geometry and the pre-construction sedimentation, which generally reflects physical processes controlling sediment transport. Also, sediment type, rather than structure type, seems to influence SAV (plants need sand).

  3. Chesapeake Bay Program Grant Guidance

    EPA Pesticide Factsheets

    Grant Guidance and appendices for the Chesapeake Bay Program that describes how the U.S. Environmental Protection Agency’s (EPA) Region 3’s Chesapeake Bay Program Office (CBPO) administers grant and cooperative agreement funds.

  4. An Expanded Chesapeake Bay Impact Structure, Eastern Virginia: New Corehole and Geophysical Data

    NASA Technical Reports Server (NTRS)

    Powars, D. S.; Johnson, G. H.; Edwards, L. E.; Horton, J. W., Jr.; Gohn, G. S.; Catchings, R. D.; McFarland, E. R.; Izett, G. A.; Bruce, T. S.; Levine, J. S.

    2002-01-01

    Data from several deep coreholes, seismic reflection surveys, and surface mapping indicate that the buried Chesapeake Bay impact structure is wider (160 km, due to 35-km-wide outer fracture zone) and deeper (2 miles) than previously reported. Additional information is contained in the original extended abstract.

  5. An ecological assessment of land use impacts in small watersheds of the Chesapeake Bay

    Treesearch

    Andrew Leight; John Jacobs; Lonnie Gonsalves; Gretchen Messick; Shawn McLaughlin; Jay Lewis; Juliana Brush; Eric Daniels; Matthew Rhodes; Lewis Collier; Robert Wood

    2016-01-01

    The Chesapeake Bay, the nation’s largest estuary, remains in relatively poor condition despite intensive public and scientific attention. In order to better understand the stressors and impacts occurring in the Bay as a result of land management decisions we conducted an assessment of both habitat condition and organismal response in three small watersheds of the upper...

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Chesapeake Bay Critters

    ERIC Educational Resources Information Center

    Mackay-Atha, Lynne

    2005-01-01

    When students enter the author's classroom on the first day of school, they are greeted with live crabs scuttling around in large bins. The crabs are her way of grabbing students' attention and launching the unit on the Chesapeake Bay watershed. She chooses to start the year with this unit because, despite the fact that the Potomac River can be…

  8. Impact effects and regional tectonic insights: Backstripping the Chesapeake Bay impact structure

    USGS Publications Warehouse

    Hayden, T.; Kominz, M.; Powars, D.S.; Edwards, L.E.; Miller, K.G.; Browning, J.V.; Kulpecz, A.A.

    2008-01-01

    The Chesapeake Bay impact structure is a ca. 35.4 Ma crater located on the eastern seaboard of North America. Deposition returned to normal shortly after impact, resulting in a unique record of both impact-related and subsequent passive margin sedimentation. We use backstripping to show that the impact strongly affected sedimentation for 7 m.y. through impact-derived crustal-scale tectonics, dominated by the effects of sediment compaction and the introduction and subsequent removal of a negative thermal anomaly instead of the expected positive thermal anomaly. After this, the area was dominated by passive margin thermal subsidence overprinted by periods of regional-scale vertical tectonic events, on the order of tens of meters. Loading due to prograding sediment bodies may have generated these events. ?? 2008 The Geological Society of America.

  9. Chesapeake Bay, New England

    NASA Image and Video Library

    1994-09-30

    STS068-234-044 (30 September-11 October 1994) --- From the wetlands in Maryland to the nation's capital and onto Baltimore, this 70mm photograph from the Space Shuttle Endeavour shows some details of the historic Chesapeake Bay and Potomac River area. With the rather low altitude of Endeavour at 115 nautical miles, features as small as Kennedy Memorial Stadium and Andrews Air Force Base are clearly seen.

  10. Impact damage to dinocysts from the Late Eocene Chesapeake Bay event

    USGS Publications Warehouse

    Edwards, L.E.; Powars, D.S.

    2003-01-01

    The Chesapeake Bay impact structure, formed by a comet or meteorite that struck the Virginia continental shelf about 35.5 million years ago, is the focus of an extensive coring project by the U.S. Geological Survey and its cooperators. Organic-walled dinocysts recovered from impact-generated deposits in a deep core inside the 85-90 km-wide crater include welded organic clumps and fused, partially melted and bubbled dinocysts unlike any previously observed. Other observed damage to dinocysts consists of breakage, pitting, and folding in various combinations. The entire marine Cretaceous, Paleocene, and Eocene section that was once present at the site has been excavated and redeposited under extreme conditions that include shock, heat, collapse, tsunamis, and airfall. The preserved dinocysts reflect these conditions and, as products of a known impact, may serve as guides for recognizing impact-related deposits elsewhere. Features that are not unique to impacts, such as breakage and folding, may offer new insights into crater-history studies in general, and to the history of the Chesapeake Bay impact structure in particular. Impact-damaged dinocysts also are found sporadically in post-impact deposits and add to the story of continuing erosion and faulting of crater material.

  11. Impact of sea level rise on tidal range in Chesapeake and Delaware Bays

    NASA Astrophysics Data System (ADS)

    Lee, Serena Blyth; Li, Ming; Zhang, Fan

    2017-05-01

    Coastal inundation is affected not only by rising mean sea level but also by changing tides. A numerical model is developed to investigate how sea level rise and coastline changes may impact tides in two coastal-plain estuaries, Chesapeake Bay and Delaware Bay. Despite their different tidal characteristics, the two estuaries display similar responses to the sea level rise and shoreline management scenarios. When hypothetic sea walls are erected at the present coastline to prevent low-lying land from flooding, tidal range increases, with greater amplification in the upper part of the two estuaries. When low-lying land is allowed to become permanently inundated by higher sea level, however, tidal range in both estuaries decreases. Analyses of the tidal energy budget show that the increased dissipation over the shallow water and newly inundated areas compensates for the reduced dissipation in deep water, leading to smaller tidal range. The changes in the tidal range are not proportional to the changes in the mean sea level, indicating a nonlinear tidal response to sea level rise. The ratio of tidal range change to sea level rise varies between -0.05 and 0.1 in Chesapeake Bay and between -0.2 and 0.25 in Delaware Bay. The model results suggest a potential adaptation strategy that uses inundation over low-lying areas to reduce tidal range at up-estuary locations.

  12. Ancient impact structures on modern continental shelves: The Chesapeake Bay, Montagnais, and Toms Canyon craters, Atlantic margin of North America

    USGS Publications Warehouse

    Poag, C. Wylie; Plescia, J.B.; Molzer, P.C.

    2002-01-01

    Three ancient impact craters (Chesapeake Bay - 35.7 Ma; Toms Canyon - 35.7 Ma; Montagnais - 51 Ma) and one multiring impact basin (Chicxulub - 65 Ma) are currently known to be buried beneath modern continental shelves. All occur on the passive Atlantic margin of North America in regions extensively explored by seismic reflection surveys in the search for oil and gas reserves. We limit our discussion herein to the three youngest structures. These craters were created by submarine impacts, which produced many structural and morphological features similar in construction, composition, and variability to those documented in well-preserved subaerial and planetary impact craters. The subcircular Chesapeake Bay (diameter 85 km) and ovate Montagnais (diameter 45-50 km) structures display outer-rim scarps, annular troughs, peak rings, inner basins, and central peaks similar to those incorporated in the widely cited conceptual model of complex impact craters. These craters differ in several respects from the model, however. For example, the Montagnais crater lacks a raised lip on the outer rim, the Chesapeake Bay crater displays only small remnants of a raised lip, and both craters contain an unusually thick body of impact breccia. The subtriangular Toms Canyon crater (diameter 20-22 km), on the other hand, contains none of the internal features of a complex crater, nor is it typical of a simple crater. It displays a prominent raised lip on the outer rim, but the lip is present only on the western side of the crater. In addition, each of these craters contains some distinct features, which are not present in one or both of the others. For example, the central peak at Montagnais rises well above the elevation of the outer rim, whereas at Chesapeake Bay, the outer rim is higher than the central peak. The floor of the Toms Canyon crater is marked by parallel deep troughs and linear ridges formed of sedimentary rocks, whereas at Chesapeake Bay, the crater floor contains

  13. Assessing the impacts of climate change on discharge and nutrient losses from a karstic agricultural sub-basin in the Upper Chesapeake Bay watershed

    USDA-ARS?s Scientific Manuscript database

    The health of the Chesapeake Bay Basin ecosystem, which lies within the heavily populated Northeastern United States, relies on reducing nutrient loading to the Chesapeake Bay by the 2025 TMDL deadline and on into the future. Doing so requires evaluating the impact of current agricultural management...

  14. Integrated Geologic, Hydrologic, and Geophysical Investigations of the Chesapeake Bay Impact Structure, Virginia, USA: A Multi-Agency Program

    NASA Technical Reports Server (NTRS)

    Gohn, G. S.; Bruce, T. S.; Catchings, R. D.; Emry, S. R.; Johnson, G. H.; Levine, J. S.; McFarland, E. R.; Poag, C. W.; Powars, D. S.

    2001-01-01

    The Chesapeake Bay impact structure is the focus of an ongoing federal-state-local research program. Recent core drilling and geophysical surveys address the formative processes and hydrogeologic properties of this major "wet-target" impact. Additional information is contained in the original extended abstract.

  15. Eutrophication and carbon sources in Chesapeake Bay over the last 2700 yr: Human impacts in context

    USGS Publications Warehouse

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

    2003-01-01

    To compare natural variability and trends in a developed estuary with human-influenced patterns, stable isotope ratios (??13C and ??15N) were measured in sediments from five piston cores collected in Chesapeake Bay. Mixing of terrestrial and algal carbon sources primarily controls patterns of ??13Corg profiles, so this proxy shows changes in estuary productivity and in delivery of terrestrial carbon to the bay. Analyses of ??15N show periods when oxygen depletion allowed intense denitrification and nutrient recycling to develop in the seasonally stratified water column, in addition to recycling taking place in surficial sediments. These conditions produced 15N-enriched (heavy) nitrogen in algal biomass, and ultimately in sediment. A pronounced increasing trend in ??15N of +4??? started in about A.D. 1750 to 1800 at all core sites, indicating greater eutrophication in the bay and summer oxygen depletion since that time. The timing of the change correlates with the advent of widespread land clearing and tillage in the watershed, and associated increases in erosion and sedimentation. Isotope data show that the region has experienced up to 13 wet-dry cycles in the last 2700 yr. Relative sea-level rise and basin infilling have produced a net freshening trend overprinted with cyclic climatic variability. Isotope data also constrain the relative position of the spring productivity maximum in Chesapeake Bay and distinguish local anomalies from sustained changes impacting large regions of the bay. This approach to reconstructing environmental history should be generally applicable to studies of other estuaries and coastal embayments impacted by watershed development. Published by Elsevier Ltd.

  16. Eutrophication in the Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Ulanowicz, R. E.

    1978-01-01

    The advantages and limitations of using remote sensing to acquire fast reliable data on the nutrient problem in the Chesapeake Bay ecosystem are discussed. Pollution effects to phytoplankton blooms during late summer and early fall months are also considered.

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

    USGS Publications Warehouse

    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.

  18. Contaminants in Chesapeake Bay sediments, 1984-1991

    SciTech Connect

    Eskin, R.A.; Rowland, K.H.; Alegre, D.Y.

    1996-05-01

    This report presents data on sediment chemical contaminant concentrations in the Chesapeake Bay and its tidal tributaries collected between 1984 and 1991. The majority of this data collection was coordinated by Maryland and Virginia with support from the Chesapeake Bay Program. The primary objectives of this report are to describe the spatial patterns in the distribution of sediment chemical contaminants in Chesapeake Bay to sediment quality guidelines in order to identify areas where sediment chemical contaminants may adversely impact aquatic biota.

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

    USGS Publications Warehouse

    Jackson, John C.; Horton, J. Wright; Chou, I-Ming; Belkin, Harvey 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.

  20. Shock-wave-induced fracturing of calcareous nannofossils from the Chesapeake Bay impact crater

    USGS Publications Warehouse

    ,

    2003-01-01

    Fractured calcareous nannofossils of the genus Discoaster from synimpact sediments within the Chesapeake Bay impact crater demonstrate that other petrographic shock indicators exist for the cratering process in addition to quartz minerals. Evidence for shock-induced taphonomy includes marginal fracturing of rosette-shaped Discoaster species into pentagonal shapes and pressure- and temperature-induced dissolution of ray tips and edges of discoasters. Rotational deformation of individual crystallites may be the mechanism that produces the fracture pattern. Shock-wave-fractured calcareous nannofossils were recovered from synimpact matrix material representing tsunami or resurge sedimentation that followed impact. Samples taken from cohesive clasts within the crater rubble show no evidence of shock-induced fracturing. The data presented here support growing evidence that microfossils can be used to determine the intensity and timing of wet-impact cratering.

  1. Postimpact deposition in the Chesapeake Bay impact structure: Variations in eustasy, compaction, sediment supply, and passive-aggressive tectonism

    USGS Publications Warehouse

    Kulpecz, A.A.; Miller, K.G.; Browning, J.V.; Edwards, L.E.; Powars, D.S.; McLaughlin, P.P.; Harris, A.D.; Feigenson, M.D.

    2009-01-01

    The Eyreville and Exmore, Virginia, core holes were drilled in the inner basin and annular trough, respectively, of the Chesapeake Bay impact structure, and they allow us to evaluate sequence deposition in an impact crater. We provide new high-resolution geochronologic (<1 Ma) and sequence-stratigraphic interpretations of the Exmore core, identify 12 definite (and four possible) postimpact depositional sequences, and present comparisons with similar results from Eyreville and other mid- Atlantic core holes. The concurrence of increases in ??18O with Chesapeake Bay impact structure sequence boundaries indicates a primary glacioeustatic control on deposition. However, regional comparisons show the differential preservation of sequences across the mid-Atlantic margin. We explain this distribution by the compaction of impactites, regional sediment-supply changes, and the differential movement of basement structures. Upper Eocene strata are thin or missing updip and around the crater, but they thicken into the inner basin (and offshore to the southeast) due to rapid crater infilling and concurrent impactite compaction. Oligocene sequences are generally thin and highly dissected throughout the mid-Atlantic region due to sediment starvation and tectonism, except in southeastern New Jersey. Regional tectonic uplift of the Norfolk Arch coupled with a southward decrease in sediment supply resulted in: (1) largely absent Lower Miocene sections around the Chesapeake Bay impact structure compared to thick sections in New Jersey and Delaware; (2) thick Middle Miocene sequences across the Delmarva Peninsula that thin south of the Chesapeake Bay impact structure; and (3) upper Middle Miocene sections that pinch out just north of the Chesapeake Bay impact structure. Conversely, the Upper Miocene-Pliocene section is thick across Virginia, but it is poorly represented in New Jersey because of regional variations in relative subsidence. ?? 2009 The Geological Society of America.

  2. Funding Opportunities in the Chesapeake Bay Watershed

    EPA Pesticide Factsheets

    This page provides links to financial assistance opportunities to help the Chesapeake Bay jurisdictions (Delaware, District of Columbia, Maryland, New York, Pennsylvania, Virginia, and West Virginia) restore the Chesapeake Bay.

  3. Recent research on the Chesapeake Bay impact structure, USA - Impact debris and reworked ejecta

    USGS Publications Warehouse

    Horton, J.W.; Aleinikoff, J.N.; Kunk, M.J.; Gohn, G.S.; Edwards, L.E.; ,; Powars, D.S.; Izett, G.A.

    2005-01-01

    Four new coreholes in the western annular trough of the buried, late Eocene Chesapeake Bay impact structure provide samples of shocked minerals, cataclastic rocks, possible impact melt, mixed sediments, and damaged microfossils. Parautochthonous Cretaceous sediments show an upward increase in collapse, sand fluidization, and mixed sediment injections. These impact-modifi ed sediments are scoured and covered by the upper Eocene Exmore beds, which consist of highly mixed Cretaceous to Eocene sediment clasts and minor crystalline-rock clasts in a muddy quartz-glauconite sand matrix. The Exmore beds are interpreted as seawater-resurge debris flows. Shocked quartz is found as sparse grains and in rock fragments at all four sites in the Exmore, where these fallback remnants are mixed into the resurge deposit. Crystalline-rock clasts that exhibit shocked quartz or cataclastic fabrics include felsites, granitoids, and other plutonic rocks. Felsite from a monomict cataclasite boulder has a sensitive high-resolution ion microprobe U-Pb zircon age of 613 ?? 4 Ma. Leucogranite from a polymict cataclasite boulder has a similar Neoproterozoic age based on muscovite 40Ar/39Ar data. Potassium-feldspar 40Ar/39Ar ages from this leucogranite show cooling through closure (???150 ??C) at ca. 261 Ma without discernible impact heating. Spherulitic felsite is under investigation as a possible impact melt. Types of crystalline clasts, and exotic sediment clasts and grains, in the Exmore vary according to location, which suggests different provenances across the structure. Fractured calcareous nannofossils and fused, bubbled, and curled dinofl agellate cysts coexist with shocked quartz in the Exmore, and this damage may record conditions of heat, pressure, and abrasion due to impact in a shallow-marine environment. ?? 2005 Geological Society of America.

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

    USGS Publications Warehouse

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

    2015-10-28

    Since its discovery in the early 1990s, scientists have conducted deep drilling and geophysical surveys of the impact structure to find out more about its size, composition, structure, age, and biological effects and to understand its lingering influences on the regional groundwater system. These efforts culminated in the drilling of a 1-mile-deep, continuously sampled corehole in 2005 by an international group of scientists and agencies.

  5. Osmium-Isotope and Platinum-Group-Element Systematics of Impact-Melt Rocks, Chesapeake Bay Impact Structure, Virginia, USA

    NASA Technical Reports Server (NTRS)

    Lee, Seung Ryeol; Wright Horton, J., Jr.; Walker, Richard J.

    2005-01-01

    Osmium (Os) isotopes and platinum-group elements (PGEs) are useful for geochemically identifying a meteoritic component within impact structures, because meteorites are typically characterized by low (187)Os/(188)Os ratios and high PGE concentrations. In contrast, most types of crustal target rocks have high radiogenic Os and very low PGE concentrations. We have examined Os isotope and PGE systematics of impact-melt rocks and pre-impact target rocks from a 2004 test hole in the late Eocene Chesapeake Bay impact structure and from nearby coreholes. Our goal is to determine the proportion of the projectile component in the melt rock Additional information is included in the original extended abstract.

  6. Chesapeake bay nonpoint source programs

    SciTech Connect

    Not Available

    1988-01-01

    This report describes the current programs to ameliorate nonpoint sources of pollution to the Chesapeake Bay that have been developed by the four jurisdictions in cooperation with other agencies, the achievements to date in terms of pollutant removal, and recommendations for future directions of the Bay Program over the next several years.

  7. Distribution and Origin of Impact-Generated Debris: Western Annular Trough, Chesapeake Bay Impact Crater

    NASA Astrophysics Data System (ADS)

    Powars, D.; Gohn, G. S.; Bruce, T. S.; Johnson, G. H.; Cathings, R. D.; Frederiksen, N. O.; Edwards, L. E.; Self-Trail, J. M.; Pierce, H. A.

    2002-05-01

    The buried 35-million-old Chesapeake Bay impact structure is up to 160 km wide and possibly excavated 3.3 km deep. Within the CBIS is a 90-km-wide Chesapeake Bay impact crater has a 38-km-wide inner basin with a central uplift surrounded by a bowl-shaped zone of basement rocks faulted down to about 11 km depth. A 21- to 31-km-wide annular trough outside the inner basin and peak ring has a slumped terrace zone at its outer margin and is bounded by an outer rim consisting of 300- to 500-m-high gullied escarpment. An outer fracture zone up to 35 km in width surrounds the crater. The USGS and affiliated institutions recently drilled three deep coreholes in the western part of the structure's annular trough and completed high-resolution seismic reflection and audio-magnetotelluric (AMT) surveys across its southwestern margin. The coreholes are located 22.7, 19.7, and 8 km outside the inner basin. Both marine- and land-based seismic data reveal numerous faults that displace the top of basement and overlying Coastal Plain sediments in the annular trough and the outer fracture zone. Due to contrasting resistivity across the crater's margin the AMT data are useful locating the outer rim. The seismic profile from the NASA Langley Research Center, Va., and the deep Langley core (19.7 km outside the inner basin) indicate that impact-generated debris near the outer rim can be characterized by a three-part physical stratigraphy. (1) Above granitic basement rock, unit A consists of 183.8 m of parautochthonous Cretaceous sediments of the Potomac Formation, tensionally fractured in situ and disrupted during late-stage gravitational collapse of the crater. The deepest occurrence of impact-induced sediment fluidization is probably in the upper beds of unit A. Seismic data indicate unit A is pervasively disrupted by short, subvertical to low-angle faults. (2) Middle unit B consists of a clast-supported diamicton (173 m thick) containing zones of moderately deformed Potomac megaclasts

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

    USGS Publications Warehouse

    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.

  9. Postimpact deformation associated with the late Eocene Chesapeake Bay impact structure in southeastern Virginia

    USGS Publications Warehouse

    Johnson, G.H.; Kruse, S.E.; Vaughn, A.W.; Lucey, J.K.; Hobbs, C. H.; Powars, D.S.

    1998-01-01

    Upper Cenozoic strata covering the Chesapeake Bay impact structure in southeastern Virginia record intermittent differential movement around its buried rim. Miocene strata in a graben detected by seismic surveys on the York River exhibit variable thickness and are deformed above the creater rim. Fan-like interformational and intraformational angular unconformities within Pliocene-Pleistocene strata, which strike parallel to the crater rim and dip 2-3?? away from the crater center, indicate that deformation and deposition were synchronous. Concentric, large-scale crossbedded, bioclastics and bodies of Pliocene age within ~20km of the buried crater rim formed on offshore shoals, presumably as subsiding listric slump blocks rotated near the crater rim.

  10. Structural outer rim of Chesapeake Bay impact crater: Seismic and bore hole evidence

    USGS Publications Warehouse

    Poag, C.W.

    1996-01-01

    Nine seismic-reflection profiles and four continuous core holes define the gross structural and stratigraphic framework of the outer rim of the Chesapeake Bay impact crater. The rim is manifested as a 90 km diameter ring of terraced normal-fault blocks, which forms a ???320 m-1200 m high rim escarpment. The top of the rim escarpment is covered by a 20 m-30 m thick ejecta blanket. The escarpment encircles a flat-floored annular trough, which is partly filled with an ???250 m thick breccia lens (Exmore breccia). The Exmore breccia overlies a 200 m-800 m thick interval of slumped sedimentary megablocks, which, in turn, rests on crystalline basement rocks. All postimpact strata (upper Eocene to Quaternary) sag structurally into the annular trough, and most units also thicken as they cross the rim into the crater. Postimpact compaction and subsidence of the Exmore breccia have created extensive normal faulting in overlying strata.

  11. Shocking News -- Impact Effects on Marine Microfossils, Chesapeake Bay Impact Structure, Virginia

    NASA Astrophysics Data System (ADS)

    Edwards, L. E.; Self-Trail, J. M.

    2002-05-01

    Microfossils recovered from sediments generated by the Chesapeake Bay impact event show distinctive features that are the direct result of their unusual history. Individual specimens of dinoflagellates are fused, fragmented, folded, partially melted, pitted, or bubbled. Specimens of calcareous nannofossils are sheared and fractured, resulting in pentagonal, rather than round, shapes. Impact-generated deposits in the USGS-NASA Langley core (Hampton, Virginia) consist of massive slump blocks, rotated slump blocks, fluidized sediments, resurge deposits, along with an airfall component. Detailed studies of the microfossils from these deposits, particularly from the muddy quartz-glauconite sand that forms the matrix between larger clasts, reveal important aspects. Besides the obvious biostratigraphy of the late Eocene time of impact, these sediments show both localized and broadbased components of Cretaceous, Paleocene, and Eocene age. The dinoflagellate cysts and calcareous nannofossils in the matrix material show a rudimentary stratigraphy. Dinoflagellate specimens from younger pre-impact deposits are more common in the upper part of the impact-generated deposits, whereas specimens from older Tertiary pre-impact deposits are more common lower in the core. High in the section, organic material is more fragmental and less readily identifiable; low in the section, fragmentation decreases and identifiability increases. For calcareous nannofossils, Cretaceous specimens are absent from the matrix material below 242 m in the core but are more common in the upper part of the impact-generated deposits. However, shearing and fragmentation of individual nannofossil specimens appears throughout the matrix material. Preservation is distinctively different in the uppermost matrix of the resurge deposits than in the overlying silt (water-column fallout). We hope further details of the microfossils and their preservation will aid in the recognition of the various components of impact

  12. Paleontological interpretations of crater processes and infilling of synimpact sediments from the Chesapeake Bay impact structure

    USGS Publications Warehouse

    Self-Trail, Jean M.; Edwards, Lucy E.; Litwin, Ronald J.

    2009-01-01

    Biostratigraphic analysis of sedimentary breccias and diamictons in the Chesapeake Bay impact structure provides information regarding the timing and processes of late-stage gravitational crater collapse and ocean resurge. Studies of calcareous nannofossil and palynomorph assemblages in the International Continental Scientific Drilling Program (ICDP)–U.S. Geological Survey (USGS) Eyreville A and B cores show the mixed-age, mixed-preservation microfossil assemblages that are typical of deposits from the upper part of the Chesapeake Bay impact structure. Sparse, poorly preserved, possibly thermally altered pollen is present within a gravelly sand interval below the granite slab at 1392 m in Eyreville core B, an interval that is otherwise barren of calcareous nannofossils and dinocysts. Gravitational collapse of water- saturated sediments from the transient crater wall resulted in the deposition of sediment clasts primarily derived from the nonmarine Cretaceous Potomac Formation. Collapse occurred before the arrival of resurge. Low pollen Thermal Alteration Index (TAI) values suggest that these sediments were not thermally altered by contact with the melt sheet. The arrival of resurge sedimentation is identified based on the presence of diamicton zones and stringers rich in glauconite and marine microfossils at 866.7 m. This horizon can be traced across the crater and can be used to identify gravitational collapse versus ocean-resurge sedimentation. Glauconitic quartz sand diamicton dominates the sediments above 618.2 m. Calcareous nannofossil and dino-flagellate data from this interval suggest that the earliest arriving resurge from the west contained little or no Cretaceous marine input, but later resurge pulses mined Cretaceous sediments east of the Watkins core in the annular trough. Additionally, the increased distance traveled by resurge to the central crater in turbulent flow conditions resulted in the disaggregation of Paleogene unconsolidated sediments. As

  13. Paleontological interpretations of crater processes and infilling of synimpact sediments from the Chesapeake Bay impact structure

    USGS Publications Warehouse

    ,; Edwards, L.E.; Litwin, R.J.

    2009-01-01

    Biostratigraphic analysis of sedimentary breccias and diamictons in the Chesapeake Bay impact structure provides information regarding the timing and processes of late-stage gravitational crater collapse and ocean resurge. Studies of calcareous nannofossil and palynomorph assemblages in the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville A and B cores show the mixed-age, mixed-preservation microfossil assemblages that are typical of deposits from the upper part of the Chesapeake Bay impact structure. Sparse, poorly preserved, possibly thermally altered pollen is present within a gravelly sand interval below the granite slab at 1392 m in Eyreville core B, an interval that is otherwise barren of calcareous nannofossils and dinocysts. Gravitational collapse of watersaturated sediments from the transient crater wall resulted in the deposition of sediment clasts primarily derived from the nonmarine Cretaceous Potomac Formation. Collapse occurred before the arrival of resurge. Low pollen Thermal Alteration Index (TAI) values suggest that these sediments were not thermally altered by contact with the melt sheet. The arrival of resurge sedimentation is identified based on the presence of diamicton zones and stringers rich in glauconite and marine microfossils at 866.7 m. This horizon can be traced across the crater and can be used to identify gravitational collapse versus ocean-resurge sedimentation. Glauconitic quartz sand diamicton dominates the sediments above 618.2 m. Calcareous nannofossil and dinoflagellate data from this interval suggest that the earliest arriving resurge from the west contained little or no Cretaceous marine input, but later resurge pulses mined Cretaceous sediments east of the Watkins core in the annular trough. Additionally, the increased distance traveled by resurge to the central crater in turbulent flow conditions resulted in the disaggregation of Paleogene unconsolidated sediments. As a

  14. Impacts of land cover changes on hurricane storm surge in the lower Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Denton, M.; Lawler, S.; Ferreira, C.

    2013-12-01

    The Chesapeake Bay is the largest estuary in the United States with more than 150 rivers draining into the bay's tidal wetlands. Coastal wetlands and vegetation play an important role in shaping the hydrodynamics of storm surge events by retaining water and slowing the propagation of storm surge. In this way coastal wetlands act as a natural barrier to inland flooding, particularly against less intense storms. Threats to wetlands come from both land development (residential or commercial/industrial) and sea level rise. The lower region of the Chesapeake Bay near its outlet is especially vulnerable to flooding from Atlantic storm surge brought in by hurricanes, tropical storms and nor'easters (e.g., hurricanes Isabel [2003] and Sandy [2012]). This region is also intensely developed with nearly 1.7 million residents within the greater Hampton Roads metropolitan area. Anthropogenic changes to land cover in the lower bay can directly impact basin drainage and storm surge propagation with impacts reaching beyond the immediate coastal zone to affect flooding in inland areas. While construction of seawall barriers around population centers may provide storm surge protection to a specifically defined area, these barriers deflect storm surge rather than attenuate it, underscoring the importance of wetlands. To analyze these impacts a framework was developed combining numerical simulations with a detailed hydrodynamic characterization of flow through coastal wetland areas. Storm surges were calculated using a hydrodynamic model (ADCIRC) coupled to a wave model (SWAN) forced by an asymmetric hurricane vortex model using the FEMA region 3 unstructured mesh (2.3 million nodes) under a High Performance Computing (HPC) environment. Multiple model simulations were performed using historical hurricanes data and hypothetical storms to compare the predicted storm surge inundation with various levels of wetland reduction and/or beach hardening. These data were combined and overlaid

  15. Biofuels and the bay: Characterizing health and ecosystem impacts in the Chesapeake

    EPA Science Inventory

    The global climate crisis has stimulated the search for alternative fuels. Biofuels have been the focus of a recent report by the Chesapeake Bay Commission that evaluated alternative fuel development efforts in the local area. Already under stress from anthropomorphic factors,...

  16. Biofuels and the bay: Characterizing health and ecosystem impacts in the Chesapeake

    EPA Science Inventory

    The global climate crisis has stimulated the search for alternative fuels. Biofuels have been the focus of a recent report by the Chesapeake Bay Commission that evaluated alternative fuel development efforts in the local area. Already under stress from anthropomorphic factors,...

  17. Physical Properties of Suevite Section of the Eyreville Core, Chesapeake Bay Impact Structure

    NASA Astrophysics Data System (ADS)

    Elbra, T.; Pesonen, L. J.

    2007-12-01

    Chesapeake is a 35 Ma old shallow marine, complex impact structure with a diameter of ca. 85 km. The structure has previously been mapped with shallow drillings. Recently, the deep drilling into inner crater zone near Cape Charles was carried out in order to provide constraints on cratering processes in multi-layered marine targets. The Eyreville-1 core includes three holes with total depth of 1766m (Gohn et al. 2006). We are analyzing the fragments of the Eyreville core including post-impact, impact and basement units of the structure. The sampling interval was chosen dense enough to allow high-resolution petrophysical, paleomagnetic and rock magnetic data to be extracted from the core. Hereby we report the preliminary petrophysical and rock-magnetic data from suevite section of Eyreville core B. Results obtained so far show large variations in magnetic susceptibility data of suevite section. Polymict lithic breccias and cataclasites in lower part of the section are characterized by low magnetic susceptibility (below 0.0003 SI). The upper part, however, consists of more magnetic (susceptibility up to 0.006 SI) suevites. The rock- magnetic measurements (including thermal behavior of magnetic susceptibility and magnetic hysteresis) show the presence of magnetites in lower part of the section. Upper part shows additionally a distinct change in the slope of the susceptibility curve also near 350C, which may indicate the presence of pyrrhotites or maghemites. More extensive studies will be applied in near future in order to clarify the magnetomineralogy and will be presented. References: G. S. Gohn, C. Koeberl, K. G. Miller, W. U. Reimold, C. S. Cockell, J. W. Horton, W. E. Sanford, M. A. Voytek, 2006. Chesapeake Bay Impact Structure Drilled. EOS, vol 87. nr 35

  18. The Chesapeake Bay bolide impact: A convulsive event in Atlantic Coastal Plain evolution

    USGS Publications Warehouse

    Poag, C.W.

    1997-01-01

    Until recently, Cenozoic evolution of the Atlantic Coastal Plain has been viewed as a subcyclical continuum of deposition and erosion. Marine transgressions alternated with regressions on a slowly subsiding passive continental margin, their orderly succession modified mainly by isostatic adjustments, occasional Appalachian tectonism, and paleoclimatic change. This passive scenario was dramatically transformed in the late Eocene, however, by a bolide impact on the inner continental shelf. The resultant crater is now buried 400-500 m beneath lower Chesapeake Bay, its surrounding peninsulas, and the continental shelf east of Delmarva Peninsula. This convulsive event, and the giant tsunami it engendered, fundamentally changed the regional geological framework and depositional regime of the Virginia Coastal Plain, and produced the following principal consequences. (1) The impact excavated a roughly circular crater, twice the size of Rhode Island (???6400 km2) and nearly as deep as the Grand Canyon (???1.3 km deep). (2) The excavation truncated all existing ground-water aquifers in the target area by gouging ???4300 km3 of rock from the upper lithosphere, including Proterozoic and Paleozoic crystalline basement rocks and Middle Jurassic to upper Eocene sedimentary rocks. (3) Synimpact depositional processes, including ejecta fallback, massive crater-wall failure, water-column collapse, and tsunami backwash, filled the crater with a porous breccia lens, 600-1200 m thick, at a phenomenal rate of ???1200 m/hr. The breccia lens replaced the truncated ground-water aquifers with a single 4300 km3 reservoir, characterized by ground water ???1.5 times saltier than normal sea water (chlorinities as high as 25,700 mg/l). (4) A structural and topographic low, created by differential subsidence of the compacting breccia, persisted over the crater at least through the Pleistocene. In the depression are preserved postimpact marine lithofacies and biofacies (upper Eocene, lower

  19. The Chesapeake Bay bolide impact: a convulsive event in Atlantic Coastal Plain evolution

    NASA Astrophysics Data System (ADS)

    Poag, C. Wylie

    1997-02-01

    Until recently, Cenozoic evolution of the Atlantic Coastal Plain has been viewed as a subcyclical continuum of deposition and erosion. Marine transgressions alternated with regressions on a slowly subsiding passive continental margin, their orderly succession modified mainly by isostatic adjustments, occasional Appalachian tectonism, and paleoclimatic change. This passive scenario was dramatically transformed in the late Eocene, however, by a bolide impact on the inner continental shelf. The resultant crater is now buried 400-500 m beneath lower Chesapeake Bay, its surrounding peninsulas, and the continental shelf east of Delmarva Peninsula. This convulsive event, and the giant tsunami it engendered, fundamentally changed the regional geological framework and depositional regime of the Virginia Coastal Plain, and produced the following principal consequences. (1) The impact excavated a roughly circular crater, twice the size of Rhode Island (˜6400 km 2) and nearly as deep as the Grand Canyon (˜1.3 km deep). (2) The excavation truncated all existing ground-water aquifers in the target area by gouging ˜4300 km 3 of rock from the upper lithosphere, including Proterozoic and Paleozoic crystalline basement rocks and Middle Jurassic to upper Eocene sedimentary rocks. (3) Synimpact depositional processes, including ejecta fallback, massive crater-wall failure, water-column collapse, and tsunami backwash, filled the crater with a porous breccia lens, 600-1200 m thick, at a phenomenal rate of ˜1200 m/hr. The breccia lens replaced the truncated ground-water aquifers with a single 4300 km 3 reservoir, characterized by ground water ˜1.5 times saltier than normal sea water (chlorinities as high as 25,700 mg/l). (4) A structural and topographic low, created by differential subsidence of the compacting breccia, persisted over the crater at least through the Pleistocene. In the depression are preserved postimpact marine lithofacies and biofacies (upper Eocene, lower Oligocene

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

    NASA Astrophysics Data System (ADS)

    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

  1. Chesapeake Bay: Introduction to an Ecosystem.

    ERIC Educational Resources Information Center

    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…

  2. Long-term simulation of vertical transport process and its impact on bottom DO in Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Du, J.; Shen, J.

    2016-02-01

    Hypoxia in coastal waters is a widespread phenomenon that appears to have been growing globally for at least 60 years. The fact that physical transport processes and biological processes are equally important in determining the bottom DO in Chesapeake Bay is commonly agreed. However, the quantitative impact of physical transport processes is rarely documented. In this study, we use a timescale, vertical exchange time (VET), to quantify the impact of all physical processes that might have on the bottom DO. Simulation of VET from 1985 to 2012 is conducted and the monthly observed DO data along the deep channel in the Bay's main stem is collected. A conceptual bottom DO budget model is applied, using the VET to quantify the physical condition and net oxygen consumption rate to quantify biological activities. The DO budget model results show that the interannual variations of physical conditions accounts for 88.8% of the interannual variations of observed DO. The high similarity between the VET spatial pattern and the observed DO suggests that physical processes play a key role in regulating the DO condition. Model results also show that long-term VET has a slight increase in summer, but no statistically significant trend is found. Correlations among southerly wind strength, North Atlantic Oscillation index, and VET demonstrate that the physical condition in the Chesapeake Bay is highly controlled by the large-scale climate variation. The relationship is most significant during the summer, when the southerly wind dominates throughout the Chesapeake Bay.

  3. Chesapeake Bay Basin Comprehensive List of Toxic Substances

    SciTech Connect

    Not Available

    1992-04-01

    The Chesapeake Bay Basin Comprehensive List of Toxic Substances is a compilation of the toxic substances detected in, released, or applied to all media (water, soil, sediment, tissue and air) within the Chesapeake Bay basin. A substance's inclusion in this list does not constitute evidence of potential or existing environmental impact. It merely documents a finding or measurement in some media at some point in time. This Comprehensive List serves two specific purposes: It is the central listing of toxic substances around which the Chesapeake Bay Program's Toxics Data Base has been structured and organized, and it defines the 'universe' of toxic substances from which future revisions and updates to the Chesapeake Bay Toxics of Concern List will be ranked and identified. The Comprehensive List is being published as a document to meet other potential uses by the Chesapeake Bay Program agencies such as defining parameter lists for toxics monitoring programs.

  4. State of the Chesapeake Bay

    SciTech Connect

    Mackiernan, G.B. )

    1990-09-01

    The US EPA undertook a six year study of the Chesapeake Bay-the US's largest estuary, as an example of the plight of estuarine and coastal waters where population growth and development, alteration of habitats, and discharge of pollutants have resulted in degrading environmental quality and productivity. This article discusses some of the results of the EPA's study.

  5. New surveys of the Chesapeake Bay impact structure suggest melt pockets and target-structure effect

    USGS Publications Warehouse

    Shah, A.K.; Brozena, J.; Vogt, P.; Daniels, D.; Plescia, J.

    2005-01-01

    We present high-resolution gravity and magnetic field survey results over the 85-km-diameter Chesapeake Bay impact structure. Whereas a continuous melt sheet is anticipated at a crater this size, shallow-source magnetic field anomalies of ???100 nT instead suggest that impact melt pooled in kilometer-scaled pockets surrounding the base of a central peak. A central anomaly of ???300 nT may represent additional melt or rock that underwent shock-induced remagnetization. Models predict that the total volume of the melt ranges from ???0.4 to 10 km3, a quantity that is several orders of magnitude smaller than expected for an impact structure this size. However, this volume is within predictions given a transient crater of diameter of 20-40 km for a target covered with water and sedimentary deposits such that melt fragments were widely dispersed at the time of impact. Gravity data delineate a gently sloping inner basin and a central peak via a contrast between crystalline and sedimentary rock. Both features are ovoid, oriented parallel to larger preimpact basement structures. Conceptual models suggest how lateral differences in rock strength due to these preimpact structures helped to shape the crater's morphology during transient-crater modification. ?? 2005 Geological Society of America.

  6. Attenuation of Storm Surge Flooding By Wetlands in the Chesapeake Bay: An Integrated Geospatial Framework Evaluating Impacts to Critical Infrastructure

    NASA Astrophysics Data System (ADS)

    Khalid, A.; Haddad, J.; Lawler, S.; Ferreira, C.

    2014-12-01

    Areas along the Chesapeake Bay and its tributaries are extremely vulnerable to hurricane flooding, as evidenced by the costly effects and severe impacts of recent storms along the Virginia coast, such as Hurricane Isabel in 2003 and Hurricane Sandy in 2012. Coastal wetlands, in addition to their ecological importance, are expected to mitigate the impact of storm surge by acting as a natural protection against hurricane flooding. Quantifying such interactions helps to provide a sound scientific basis to support planning and decision making. Using storm surge flooding from various historical hurricanes, simulated using a coupled hydrodynamic wave model (ADCIRC-SWAN), we propose an integrated framework yielding a geospatial identification of the capacity of Chesapeake Bay wetlands to protect critical infrastructure. Spatial identification of Chesapeake Bay wetlands is derived from the National Wetlands Inventory (NWI), National Land Cover Database (NLCD), and the Coastal Change Analysis Program (C-CAP). Inventories of population and critical infrastructure are extracted from US Census block data and FEMA's HAZUS-Multi Hazard geodatabase. Geospatial and statistical analyses are carried out to develop a relationship between wetland land cover, hurricane flooding, population and infrastructure vulnerability. These analyses result in the identification and quantification of populations and infrastructure in flooded areas that lie within a reasonable buffer surrounding the identified wetlands. Our analysis thus produces a spatial perspective on the potential for wetlands to attenuate hurricane flood impacts in critical areas. Statistical analysis will support hypothesis testing to evaluate the benefits of wetlands from a flooding and storm-surge attenuation perspective. Results from geospatial analysis are used to identify where interactions with critical infrastructure are relevant in the Chesapeake Bay.

  7. Metagenomic Characterization of Chesapeake Bay Virioplankton▿ †

    PubMed Central

    Bench, Shellie R.; Hanson, Thomas E.; Williamson, Kurt E.; Ghosh, Dhritiman; Radosovich, Mark; Wang, Kui; Wommack, K. Eric

    2007-01-01

    Viruses are ubiquitous and abundant throughout the biosphere. In marine systems, virus-mediated processes can have significant impacts on microbial diversity and on global biogeocehmical cycling. However, viral genetic diversity remains poorly characterized. To address this shortcoming, a metagenomic library was constructed from Chesapeake Bay virioplankton. The resulting sequences constitute the largest collection of long-read double-stranded DNA (dsDNA) viral metagenome data reported to date. BLAST homology comparisons showed that Chesapeake Bay virioplankton contained a high proportion of unknown (homologous only to environmental sequences) and novel (no significant homolog) sequences. This analysis suggests that dsDNA viruses are likely one of the largest reservoirs of unknown genetic diversity in the biosphere. The taxonomic origin of BLAST homologs to viral library sequences agreed well with reported abundances of cooccurring bacterial subphyla within the estuary and indicated that cyanophages were abundant. However, the low proportion of Siphophage homologs contradicts a previous assertion that this family comprises most bacteriophage diversity. Identification and analyses of cyanobacterial homologs of the psbA gene illustrated the value of metagenomic studies of virioplankton. The phylogeny of inferred PsbA protein sequences suggested that Chesapeake Bay cyanophage strains are endemic in that environment. The ratio of psbA homologous sequences to total cyanophage sequences in the metagenome indicated that the psbA gene may be nearly universal in Chesapeake Bay cyanophage genomes. Furthermore, the low frequency of psbD homologs in the library supports the prediction that Chesapeake Bay cyanophage populations are dominated by Podoviridae. PMID:17921274

  8. Metagenomic characterization of Chesapeake Bay virioplankton.

    PubMed

    Bench, Shellie R; Hanson, Thomas E; Williamson, Kurt E; Ghosh, Dhritiman; Radosovich, Mark; Wang, Kui; Wommack, K Eric

    2007-12-01

    Viruses are ubiquitous and abundant throughout the biosphere. In marine systems, virus-mediated processes can have significant impacts on microbial diversity and on global biogeocehmical cycling. However, viral genetic diversity remains poorly characterized. To address this shortcoming, a metagenomic library was constructed from Chesapeake Bay virioplankton. The resulting sequences constitute the largest collection of long-read double-stranded DNA (dsDNA) viral metagenome data reported to date. BLAST homology comparisons showed that Chesapeake Bay virioplankton contained a high proportion of unknown (homologous only to environmental sequences) and novel (no significant homolog) sequences. This analysis suggests that dsDNA viruses are likely one of the largest reservoirs of unknown genetic diversity in the biosphere. The taxonomic origin of BLAST homologs to viral library sequences agreed well with reported abundances of cooccurring bacterial subphyla within the estuary and indicated that cyanophages were abundant. However, the low proportion of Siphophage homologs contradicts a previous assertion that this family comprises most bacteriophage diversity. Identification and analyses of cyanobacterial homologs of the psbA gene illustrated the value of metagenomic studies of virioplankton. The phylogeny of inferred PsbA protein sequences suggested that Chesapeake Bay cyanophage strains are endemic in that environment. The ratio of psbA homologous sequences to total cyanophage sequences in the metagenome indicated that the psbA gene may be nearly universal in Chesapeake Bay cyanophage genomes. Furthermore, the low frequency of psbD homologs in the library supports the prediction that Chesapeake Bay cyanophage populations are dominated by Podoviridae.

  9. Impact of point and nonpoint source pollution on pore waters of two Chesapeake Bay tributaries.

    PubMed

    Karuppiah, M; Gupta, G

    1996-10-01

    Chesapeake Bay and its tributaries are contaminated by industrial and municipal point sources and agricultural nonpoint sources of pollution. The objective of this study was to compare the porewater characteristics of two Chesapeake Bay tributaries: Wicomico River (WR) contaminated by point source and Pocomoke River (PR) contaminated by both point and nonpoint sources of pollution. Four study sites (1 mile before, adjacent to, and 1 and 2 miles after the sewage treatment plant) were chosen to collect sediment samples in both the rivers. The sediment-pore waters were analyzed for toxicity using Microtox marine luminescent bacteria-Vibrio fischeri. USEPA toxicity identification evaluation tests on these pore waters confirmed that the contaminants (ammonia and heavy metals) in WR were from municipal point sources, whereas in PR the contamination (metals, pesticides, and PCBs) was from nonpoint sources (agriculture) of pollution. The toxicity (and the concentration of contaminants) decreased both upstream and downstream from the most polluted site in both the rivers.

  10. Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure

    USGS Publications Warehouse

    Poag, C.W.

    2005-01-01

    This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. ?? 2005 Geological Society of America.

  11. Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure

    USGS Publications Warehouse

    Poag, C.W.

    2005-01-01

    This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. 

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

    NASA Technical Reports Server (NTRS)

    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

  13. Real World: NASA and the Chesapeake Bay

    NASA Image and Video Library

    Learn how NASA uses Earth observing satellites to monitor conditions in the Chesapeake Bay over time. Information about pollution, eutrophication, land cover and watershed runoff helps water manage...

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

    USGS Publications Warehouse

    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.

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

    USGS Publications Warehouse

    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.

  16. The Chesapeake Bay bolide impact: a new view of coastal plain evolution

    USGS Publications Warehouse

    Poag, C. Wylie

    1998-01-01

    A spectacular geological event took place on the Atlantic margin of North America about 35 million years ago in the late part of the Eocene Epoch. Sea level was unusually high everywhere on Earth, and the ancient shoreline of the Virginia region was somewhere in the vicinity of where Richmond is today (fig. 1). Tropical rain forests covered the slopes of the Appalachians. To the east of a narrow coastal plain, a broad, lime (calcium carbonate)- covered continental shelf lay beneath the ocean. Suddenly, with an intense flash of light, that tranquil scene was transformed into a hellish cauldron of mass destruction. From the far reaches of space, a bolide (comet or asteroid), 3-5 kilometers in diameter, swooped through the Earth's atmosphere and blasted an enormous crater into the continental shelf. The crater is now approximately 200 km southeast of Washington, D.C., and is buried 300-500 meters beneath the southern part of Chesapeake Bay and the peninsulas of southeastern Virginia (fig. 1). The entire bolide event, from initial impact to the termination of breccia deposition, lasted only a few hours or days. The crater was then buried by additional sedimentary beds, which accumulated during the following 35 million years.

  17. A simulation of the hydrothermal response to the Chesapeake Bay bolide impact

    USGS Publications Warehouse

    Sanford, W.E.

    2005-01-01

    Groundwater more saline than seawater has been discovered in the tsunami breccia of the Chesapeake Bay impact Crater. One hypothesis for the origin of this brine is that it may be a liquid residual following steam separation in a hydrothermal system that evolved following the impact. Initial scoping calculations have demonstrated that it is feasible such a residual brine could have remained in the crater for the 35 million years since impact. Numerical simulations have been conducted using the code HYDROTHERM to test whether or not conditions were suitable in the millennia following the impact for the development of a steam phase in the hydrothermal system. Hydraulic and thermal parameters were estimated for the bedrock underlying the crater and the tsunami breccia that fills the crater. Simulations at three different breccia permeabilities suggest that the type of hydrothermal system that might have developed would have been very sensitive to the permeability. A relatively low breccia permeability (1 ?? 10-16 m2) results in a system partitioned into a shallow water phase and a deeper superheated steam phase. A moderate breccia permeability (1 ?? 10-15 m2 ) results in a system with regionally extensive multiphase conditions. A relatively high breccia permeability (1 ?? 10-14 m2 ) results in a system dominated by warm-water convection cells. The permeability of the crater breccia could have had any of these values at given depths and times during the hydrothermal system evolution as the sediments compacted. The simulations were not able to take into account transient permeability conditions, or equations of state that account for the salt content of seawater. Results suggest, however, that it is likely that steam conditions existed at some time in the system following impact, providing additional evidence that is consistent with a hydrothermal origin for the crater brine. ?? Blackwell Publishing Ltd.

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

    USGS Publications Warehouse

    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.

  19. Paleoenvironmental recovery from the Chesapeake Bay bolide impact: The benthic foraminiferal record

    USGS Publications Warehouse

    Poag, C.W.

    2009-01-01

    The late Eocene Chesapeake Bay bolide impact transformed its offshore target site from an outer neritic, midshelf seafl oor into a bathyal crater basin. To obtain a depositional record from one of the deepest parts of this basin, the U.S. Geological Survey (USGS) and the International Continental Scientifi c Drilling Program (ICDP) drilled a 1.76-km-deep core hole near Eyreville, Virginia. The Eyreville core and eight previously cored boreholes contain a rarely obtainable record of marine deposition and microfossil assemblages that characterize the transition from synimpact to postimpact paleoenvironments inside and near a submarine impact crater. I used depositional style and benthic foraminiferal assemblages to recognize a four-step transitional succession, with emphasis on the Eyreville core. Step 1 is represented by small-scale, silt-rich turbidites, devoid of indigenous microfossils, which lie directly above the crater-fi lling Exmore breccia. Step 2 is represented by very thin, parallel, silt and clay laminae, which accumulated on a relatively tranquil and stagnant seafl oor. This stagnation created a dead zone, which excluded seafl oor biota, and it lasted ~3-5 ka. Step 3 is an interval of marine clay deposition, accompanied by a burst of microfaunal activity, as a species-rich pioneer community of benthic foraminifera repopulated the impact site. The presence of a diagnostic suite of agglutinated foraminifera during step 3 indicates that paleoenvironmental stress related to the impact lasted from ~9 ka to 400 ka at different locations inside the crater. During step 4, the agglutinated assemblage disappeared, and an equilibrium foraminiferal community developed that contained nearly 100% calcareous species. In contrast to intracrater localities, core sites outside and near the crater rim show neither evidence of the agglutinated assemblage, nor other indications of long-term biotic disruption from the bolide impact

  20. Assessing water quality of the Chesapeake Bay by the impact of sea level rise and warming

    NASA Astrophysics Data System (ADS)

    Wang, P.; Linker, L.; Wang, H.; Bhatt, G.; Yactayo, G.; Hinson, K.; Tian, R.

    2017-08-01

    The influence of sea level rise and warming on circulation and water quality of the Chesapeake Bay under projected climate conditions in 2050 were estimated by computer simulation. Four estuarine circulation scenarios in the estuary were run using the same watershed load in 1991-2000 period. They are, 1) the Base Scenario, which represents the current climate condition, 2) a Sea Level Rise Scenario, 3) a Warming Scenario, and 4) a combined Sea Level Rise and Warming Scenario. With a 1.6-1.9°C increase in monthly air temperatures in the Warming Scenario, water temperature in the Bay is estimated to increase by 0.8-1°C. Summer average anoxic volume is estimated to increase 1.4 percent compared to the Base Scenario, because of an increase in algal blooms in the spring and summer, promotion of oxygen consumptive processes, and an increase of stratification. However, a 0.5-meter Sea Level Rise Scenario results in a 12 percent reduction of anoxic volume. This is mainly due to increased estuarine circulation that promotes oxygen-rich sea water intrusion in lower layers. The combined Sea Level Rise and Warming Scenario results in a 10.8 percent reduction of anoxic volume. Global warming increases precipitation and consequently increases nutrient loads from the watershed by approximately 5-7 percent. A scenario that used a 10 percent increase in watershed loads and current estuarine circulation patterns yielded a 19 percent increase in summer anoxic volume, while a scenario that used a 10 percent increase in watershed loads and modified estuarine circulation patterns by the aforementioned sea level rise and warming yielded a 6 percent increase in summer anoxic volume. Impacts on phytoplankton, sediments, and water clarity were also analysed.

  1. Structure of the Chesapeake Bay Impact Crater from Wide-Angle Seismic Waveform Tomography

    NASA Astrophysics Data System (ADS)

    Lester, W. R.; Hole, J. A.; Catchings, R. D.; Bleibinhaus, F.

    2006-12-01

    The 35 million year old Chesapeake Bay impact structure is one of the largest and most well preserved meteor/comet impact structures on Earth. As a marine impact on a continental shelf, its morphology consists of a deep inner crater penetrating pre-existing crystalline basement surrounded by a much wider, shallower crater within the overlying sediments. In 2004, the U.S. Geological Survey conducted a combined refraction and low-fold reflection seismic survey across the northern part of the inner crater with the goals of constraining crater structure and identifying an ideal drill site for a deep borehole. Waveform inversion was applied to the seismic data to produce a high-resolution seismic velocity model of the inner crater. This significantly improved the spatial resolution over previous images based on travel times. Under the northeastern part of the outer crater, eastward-sloping, relatively intact crystalline basement is at a depth of ~1.5 km. The edge of the inner crater is at ~17 km radius and slopes gradually inward to penetrate pre-existing crystalline basement. The top of crystalline rock on the central uplift is about 0.8 km higher than its surroundings. Seismic velocity of crystalline rocks under the inner crater is much lower than under the outer crater, suggesting strong fracturing/brecciation of the inner crater floor and even stronger brecciation of the central uplift. A basement uplift and lateral change of basement velocity occurs at a radius of ~12 km and is interpreted as possibly indicating the edge of the transient crater caused by impact excavation prior to collapse. Assuming a 24 km diameter transient crater, scaling laws based on extraterrestrial craters and numerical models predict the observed inner crater diameter, central uplift diameter, and inner crater depth. This suggests that the crater collapse processes that created the inner crater in crystalline rocks were unaffected by the much weaker rheology of the overlying sediments.

  2. Lower Chesapeake Bay, VA, USA

    NASA Image and Video Library

    1973-06-22

    SL2-16-174 (22 June 1973) --- Norfolk and the lower Chesapeake Bay, VA (37.5N, 75.5W) at the interface of the Atlantic Ocean can be seen to be a mixture of complex currents. Outgoing tides from the bay generate considerable turbulence as they encounter coastal currents and can be observed by the sediment plumes stirred up as a result of current dynamics. Smooth flowing water has less sediment and appears darker. Turbulent water has lots of sediment and appears lighter in color. Photo credit: NASA

  3. Processing of single channel air and water gun data for imaging an impact structure at the Chesapeake Bay

    USGS Publications Warehouse

    Lee, Myung W.

    1999-01-01

    Processing of 20 seismic profiles acquired in the Chesapeake Bay area aided in analysis of the details of an impact structure and allowed more accurate mapping of the depression caused by a bolide impact. Particular emphasis was placed on enhancement of seismic reflections from the basement. Application of wavelet deconvolution after a second zero-crossing predictive deconvolution improved the resolution of shallow reflections, and application of a match filter enhanced the basement reflections. The use of deconvolution and match filtering with a two-dimensional signal enhancement technique (F-X filtering) significantly improved the interpretability of seismic sections.

  4. NASA Satellites Aid in Chesapeake Bay Recovery

    NASA Image and Video Library

    By studying the landscape around the Chesapeake Bay, NASA spacecrafts are helping land managers figure out how to battle the harmful pollutants that have added to the destruction of the bay's once ...

  5. Chesapeake Bay basinwide toxics reduction strategy reevaluation report

    SciTech Connect

    Not Available

    1994-09-01

    The 1987 Chesapeake Bay Agreement committed the signatories to 'develop, adopt and begin implementation of a basinwide strategy to achieve a reduction of toxics, consistent with the Clean Water Act of 1987, which will ensure protection of human health and living resources.' The resultant Chesapeake Bay Basinwide Toxics Reduction Strategy, adopted by the Chesapeake Executive Council in January 1989, initiated a multi-jurisdictional effort to define the nature, extent, and magnitude of Chesapeake Bay toxics problems more accurately and initiate specific toxics reduction and prevention actions. The Chesapeake Bay Agreement signatories also committed to reevaluate the strategy during 1992. The objectives of this strategy reevaluation were to define: what we now know about the nature, extent, and magnitude of Bay toxics problems; what steps should be taken to reduce and prevent impacts from chemical contaminants; and what information is still needed to determine future actions. The Chesapeake Bay Program's Toxics Subcommittee investigated and evaluated the complex nature of the Bay's toxics problems through a two-year schedule of meetings, research workshops, and information-gathering forums. This report not only documents the findings of the two-year information gathering process of the strategy reevaluation but also recommends an approach for undertaking future toxics reduction and prevention actions in the Bay watershed.

  6. Chesapeake Bay Program: Point-Source Atlas

    SciTech Connect

    Macknis, J.

    1988-08-01

    The atlas contains pollutant loadings from Chesapeake Bay watershed municipal and industrial point sources drawn from the Chesapeake Bay Program computerized data base. Nutrient and toxic discharges are included. Effluent data are averaged for the calendar year 1985. Detailed information is presented in 23 tables and 14 figures.

  7. Chesapeake Bay Watershed - Protecting the Chesapeake Bay and its rivers through science, restoration, and partnership

    USGS Publications Warehouse

    ,

    2012-01-01

    The Chesapeake Bay, the Nation's largest estuary, has been degraded due to the impact of human-population increase, which has doubled since 1950, resulting in degraded water quality, loss of habitat, and declines in populations of biological communities. Since the mid-1980s, the Chesapeake Bay Program (CBP), a multi-agency partnership which includes the Department of Interior (DOI), has worked to restore the Bay ecosystem. The U.S. Geological Survey (USGS) has the critical role of providing unbiased scientific information that is utilized to document and understand ecosystem change to help assess the effectiveness of restoration strategies in the Bay and its watershed. The USGS revised its Chesapeake Bay science plan for 2006-2011 to address the collective needs of the CBP, DOI, and USGS with a mission to provide integrated science for improved understanding and management of the Bay ecosystem. The USGS science themes for this mission are: Causes and consequences of land-use change; Impact of climate change and associated hazards; Factors affecting water quality and quantity; Ability of habitat to support fish and bird populations; and Synthesis and forecasting to improve ecosystem assessment, conservation, and restoration.

  8. Impact of environmental policies on the adoption of manure management practices in the Chesapeake Bay watershed.

    PubMed

    Savage, Jeff A; Ribaudo, Marc O

    2013-11-15

    Pollution in the Chesapeake Bay is a problem and has been a focus of federal and state initiatives to reduce nutrient pollution from agriculture and other sources since 1983. In 2010 EPA established a TMDL for the watershed. Producers may voluntarily respond to intense and focused policy scrutiny by adopting best management practices. A detailed analysis of water quality best management practices by animal feeding operations inside and outside the watershed yield insight into this relationship. Our findings support the hypothesis that farmers will adopt water quality measures if links are made clear and there is an expectation of future regulations. Published by Elsevier Ltd.

  9. High-resolution seismic-reflection images across the ICDP-USGS Eyreville deep drilling site, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Powars, D.S.; Catchings, R.D.; Goldman, M.R.; Gohn, G.S.; Horton, J.W.; Edwards, L.E.; Rymer, M.J.; Gandhok, G.

    2009-01-01

    The U.S. Geological Survey (USGS) acquired two 1.4-km-long, high-resolution (??5 m vertical resolution) seismic-reflection lines in 2006 that cross near the International Continental Scientifi c Drilling Program (ICDP)-USGS Eyreville deep drilling site located above the late Eocene Chesapeake Bay impact structure in Virginia, USA. Five-meter spacing of seismic sources and geophones produced high-resolution images of the subsurface adjacent to the 1766-m-depth Eyreville core holes. Analysis of these lines, in the context of the core hole stratigraphy, shows that moderateamplitude, discontinuous, dipping reflections below ??527 m correlate with a variety of Chesapeake Bay impact structure sediment and rock breccias recovered in the cores. High-amplitude, continuous, subhorizontal reflections above ??527 m depth correlate with the uppermost part of the Chesapeake Bay impact structure crater-fi ll sediments and postimpact Eocene to Pleistocene sediments. Refl ections with ??20-30 m of relief in the uppermost part of the crater-fi ll and lowermost part of the postimpact section suggest differential compaction of the crater-fi ll materials during early postimpact time. The top of the crater-fi ll section also shows ??20 m of relief that appears to represent an original synimpact surface. Truncation surfaces, locally dipping reflections, and depth variations in reflection amplitudes generally correlate with the lithostratigraphic and sequence-stratigraphic units and contacts in the core. Seismic images show apparent postimpact paleochannels that include the fi rst possible Miocene paleochannels in the Mid-Atlantic Coastal Plain. Broad downwarping in the postimpact section unrelated to structures in the crater fi ll indicates postimpact sediment compaction. ?? 2009 The Geological Society of America.

  10. High-resolution seismic-reflection images across the ICDP-USGS Eyreville deep drilling site, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Powars, David S.; Catchings, Rufus D.; Goldman, Mark R.; Gohn, Gregory S.; Horton, J. Wright; Edwards, Lucy E.; Rymer, Michael J.; Gandhok, Gini

    2009-01-01

    The U.S. Geological Survey (USGS) acquired two 1.4-km-long, high-resolution (~5 m vertical resolution) seismic-reflection lines in 2006 that cross near the International Continental Scientific Drilling Program (ICDP)-USGS Eyreville deep drilling site located above the late Eocene Chesapeake Bay impact structure in Virginia, USA. Five-meter spacing of seismic sources and geophones produced high-resolution images of the subsurface adjacent to the 1766-m-depth Eyreville core holes. Analysis of these lines, in the context of the core hole stratigraphy, shows that moderate-amplitude, discontinuous, dipping reflections below ~527 m correlate with a variety of Chesapeake Bay impact structure sediment and rock breccias recovered in the cores. High-amplitude, continuous, subhorizontal reflections above ~527 m depth correlate with the uppermost part of the Chesapeake Bay impact structure crater-fill sediments and postimpact Eocene to Pleistocene sediments. Reflections with ~20-30 m of relief in the uppermost part of the crater-fill and lowermost part of the postimpact section suggest differential compaction of the crater-fill materials during early postimpact time. The top of the crater-fill section also shows ~20 m of relief that appears to represent an original synimpact surface. Truncation surfaces, locally dipping reflections, and depth variations in reflection amplitudes generally correlate with the lithostrati-graphic and sequence-stratigraphic units and contacts in the core. Seismic images show apparent postimpact paleochannels that include the first possible Miocene paleochannels in the Mid-Atlantic Coastal Plain. Broad downwarping in the postim-pact section unrelated to structures in the crater fill indicates postimpact sediment compaction.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Petrography of the Suevite-like Depth Interval (1397-1550 m) in Drill Core Eyreville-B, Chesapeake Bay Impact Structure, USA

    NASA Astrophysics Data System (ADS)

    Wittmann, A.; Reimold, W. U.; Hansen, B.; Kenkmann, T.

    2008-03-01

    A sub-division of suevite-like deposits in a drill core through the Chesapeake Bay impact structure based on component-size distribution and petrography suggests a gradation from groundsurge to fallback within the first ~6 minutes after impact.

  13. Microbial abundance in the deep subsurface of the Chesapeake Bay impact crater: Relationship to lithology and impact processes

    USGS Publications Warehouse

    Cockell, Charles S.; Gronstal, Aaron L.; Voytek, Mary A.; Kirshtein, Julie D.; Finster, Kai; Sanford, Ward E.; Glamoclija, Mihaela; Gohn, Gregroy S.; Powars, David S.; Horton, J. Wright

    2009-01-01

    Asteroid and comet impact events are known to cause profound disruption to surface ecosystems. The aseptic collection of samples throughout a 1.76-km-deep set of cores recovered from the deep subsurface of the Chesapeake Bay impact structure has allowed the study of the subsurface biosphere in a region disrupted by an impactor. Microbiological enumerations suggest the presence of three major microbiological zones. The upper zone (127–867 m) is characterized by a logarithmic decline in microbial abundance from the surface through the postimpact section of Miocene to Upper Eocene marine sediments and across the transition into the upper layers of the impact tsunami resurge sediments and sediment megablocks. In the middle zone (867–1397 m) microbial abundances are below detection. This zone is predominantly quartz sand, primarily composed of boulders and blocks, and it may have been mostly sterilized by the thermal pulse delivered during impact. No samples were collected from the large granite block (1096–1371 m). The lowest zone (below 1397 m) of increasing microbial abundance coincides with a region of heavily impact-fractured, hydraulically conductive suevite and fractured schist. These zones correspond to lithologies influenced by impact processes. Our results yield insights into the influence of impacts on the deep subsurface biosphere.

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

    USGS Publications Warehouse

    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.

  15. MISR Views Delaware Bay, Chesapeake Bay, and the Appalachian Mountains

    NASA Image and Video Library

    2000-06-20

    These multi-angle images of Delaware Bay, Chesapeake Bay, and the Appalachian Mountains, acquired 24 March 2000 from NASA Terra spacecraft, come from the downward-looking nadir camera on the MISR instrument onboard NASA Terra satellite.

  16. Chesapeake Bay restoration and protection plan

    SciTech Connect

    Not Available

    1985-07-01

    The report presents goals and strategies for improving the water quality and living resources of the Chesapeake Bay, for the sake of the Chesapeake's productivity, ecology, and to protect public health. It also outlines the activities of seven federal agencies and of four states.

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

    USGS Publications Warehouse

    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.

  18. Assessing climate change impacts on winter cover crop nitrate uptake efficiency on the coastal plain of the Chesapeake Bay watershed using the SWAT model

    USDA-ARS?s Scientific Manuscript database

    Climate change is expected to exacerbate water quality degradation in the Chesapeake Bay watershed (CBW). Winter cover crops (WCCs) have been widely implemented in this region owing to their high effectiveness at reducing nitrate loads. However, little is known about climate change impacts on the ef...

  19. Shock deformation and nucleation of magnetic minerals in suevites of the Chesapeake Bay impact crater, USA

    NASA Astrophysics Data System (ADS)

    Mang, C.; Kontny, A. M.; Harries, D.; Langenhorst, F.; Reimold, U.

    2010-12-01

    a low grade oxidation. The magnetite clusters are suggested to represent break down products of Fe-containing minerals, but mainly of altered impact melt fragments. Considerable amounts of magnetic minerals could not be found in these fragments; moreover susceptibility measurements indicate minor amounts of magnetite. As one direction of NRM is consistent for both magnetic minerals (Elbra et al., 2009), it is lost likely that magnetite and pyrrhotite acquired their NRM within an short time period after the impact. The melt fragments, whose magnetization is considered to be dominated by a TRM, do not contribute significantly to the bulk magnetization. In contrast to previous assumptions, our results strongly indicate that CRM and SRM are dominating the rock magnetic properties of the suevite layer. Citations: Elbra, T., Kontny, A., Pesonen, L.J., 2009, Rock-magnetic properties of the ICDP-USGS Eyreville core, Chesapeake Bay impact structure, USA. Geol. Soc. Am. Spec. Pap. 458, 119 - 136

  20. Chesapeake Bay Watershed Implementation Plans (WIPs)

    EPA Pesticide Factsheets

    This page provides an overview of Watershed Implementation Plans (WIP) and how they play an important role in restoring the Chesapeake Bay. The page also provides links to each jurisdiction's Phase I, II, and III WIP.

  1. Underwater Grass Comeback Helps Chesapeake Bay

    EPA Pesticide Factsheets

    The fortified Susquehanna Flats, the largest bed of underwater grasses in the Chesapeake Bay, seems able to withstand a major weather punch. Its resilience is contributing to an overall increase in the Bay’s submerged aquatic vegetation.

  2. Chesapeake Bay plume dynamics from LANDSAT

    NASA Technical Reports Server (NTRS)

    Munday, J. C., Jr.; Fedosh, M. S.

    1981-01-01

    LANDSAT images with enhancement and density slicing show that the Chesapeake Bay plume usually frequents the Virginia coast south of the Bay mouth. Southwestern (compared to northern) winds spread the plume easterly over a large area. Ebb tide images (compared to flood tide images) show a more dispersed plume. Flooding waters produce high turbidity levels over the shallow northern portion of the Bay mouth.

  3. Chesapeake Bay atmospheric deposition study. Final report

    SciTech Connect

    Baker, J.E.; Clark, C.A.

    1996-08-01

    The results of the Chesapeake Bay Atmospheric Deposition Study (CBADS) are presented and discussed relative to the issues raised by the U.S. Environmental Protection Agency`s Great Waters Program. The primary objective of the CBADS network was to provide the best possible estimates of total, annual atmospheric loadings of a variety of trace elements and organic contaminants directly to the surface waters of the Chesapeake Bay.

  4. Improving measurement of Chesapeake Bay's dead zone

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-09-01

    In the 1930s, researchers first noticed that the Chesapeake Bay had a dead zone, an expanse of water with drastically reduced concentrations of oxygen. In the 1980s, hypoxia—low-oxygen conditions—gave way in some places to anoxia—a near-total depletion of dissolved oxygen. A lack of oxygen makes the water inhospitable for many marine organisms, and the Chesapeake Bay is the focus of major ecosystem rehabilitation efforts.

  5. Impact of fair-weather cumulus clouds and the Chesapeake Bay breeze on pollutant transport and transformation

    NASA Astrophysics Data System (ADS)

    Loughner, Christopher P.; Allen, Dale J.; Pickering, Kenneth E.; Zhang, Da-Lin; Shou, Yi-Xuan; Dickerson, Russell R.

    2011-08-01

    Two fine-scale meteorological processes, fair-weather cumulus cloud development and a bay breeze, are examined along with their impacts on air chemistry. The impact of model resolution on fair-weather cumulus cloud development, transport of pollutants through clouds, sulfur dioxide to sulfate conversion in clouds, and the development of the Chesapeake Bay breeze are examined via 13.5, 4.5, 1.5, and 0.5 km resolution simulations covering the Washington - Baltimore area. Results show that as the resolution increases, more pollutants are transported aloft through fair-weather cumulus clouds causing an increase in the rate of oxidation of sulfur dioxide to sulfate aerosols. The high resolution model runs more nearly match observations of a local pollutant maximum near the top of the boundary layer and produce an increase in boundary layer venting with subsequent pollutant export. The sensitivity of sulfur dioxide to sulfate conversion rates to cloud processing is examined by comparing sulfur dioxide and sulfate concentrations from simulations that use two different methods to diagnose clouds. For this particular event, a diagnostic method produces the most clouds and the most realistic cloud cover, has the highest oxidation rates, and generates sulfur dioxide and sulfate concentrations that agree best with observations. The differences between the simulations show the importance of accurately simulating clouds in sulfate simulations. The fidelity of the model's representation of the bay breeze is examined as a function of resolution. As the model resolution increases, a larger temperature gradient develops along the shoreline of the Chesapeake Bay causing the bay breeze to form sooner, push farther inland, and loft more pollutants upward. This stronger bay breeze results in low-level convergence, a buildup of near surface ozone over land and a decrease in the land-to-sea flux of ozone and ozone precursors as seen in measurements. The resulting 8 h maximum ozone

  6. Deriving Chesapeake Bay Water Quality Standards

    USGS Publications Warehouse

    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.

  7. Radionuclides in Chesapeake Bay sediments

    NASA Technical Reports Server (NTRS)

    Cressy, P. J., Jr.

    1976-01-01

    Natural and manmade gamma-ray emitting radionuclides were measured in Chesapeake Bay sediments taken near the Calvert Cliffs Nuclear Power Plant site. Samples represented several water depths, at six locations, for five dates encompassing a complete seasonal cycle. Radionuclide contents of dry sediments ranged as follows: Tl-208, 40 to 400 pCi/kg; Bi-214, 200 to 800 pCi/kg; K, 0.04 to 2.1 percent; Cs-137 5 to 1900 pCi/kg; Ru106, 40 to 1000 pCikg Co60, 1 to 27 pCi/kg. In general, radionuclide contents were positively correlated with each other and negatively correlated with sediment grain size.

  8. DEVELOP Chesapeake Bay Watershed Hydrology - UAV Sensor Web

    NASA Astrophysics Data System (ADS)

    Holley, S. D.; Baruah, A.

    2008-12-01

    The Chesapeake Bay is the largest estuary in the United States, with a watershed extending through six states and the nation's capital. Urbanization and agriculture practices have led to an excess runoff of nutrients and sediment into the bay. Nutrients and sediment loading stimulate the growth of algal blooms associated with various problems including localized dissolved oxygen deficiencies, toxic algal blooms and death of marine life. The Chesapeake Bay Program, among other stakeholder organizations, contributes greatly to the restoration efforts of the Chesapeake Bay. These stakeholders contribute in many ways such as monitoring the water quality, leading clean-up projects, and actively restoring native habitats. The first stage of the DEVELOP Chesapeake Bay Coastal Management project, relating to water quality, contributed to the restoration efforts by introducing NASA satellite-based water quality data products to the stakeholders as a complement to their current monitoring methods. The second stage, to be initiated in the fall 2008 internship term, will focus on the impacts of land cover variability within the Chesapeake Bay Watershed. Multiple student led discussions with members of the Land Cover team at the Chesapeake Bay Program Office in the DEVELOP GSFC 2008 summer term uncovered the need for remote sensing data for hydrological mapping in the watershed. The Chesapeake Bay Program expressed in repeated discussions on Land Cover mapping that significant portions of upper river areas, streams, and the land directly interfacing those waters are not accurately depicted in the watershed model. Without such hydrological mapping correlated with land cover data the model will not be useful in depicting source areas of nutrient loading which has an ecological and economic impact in and around the Chesapeake Bay. The fall 2008 DEVELOP team will examine the use of UAV flown sensors in connection with in-situ and Earth Observation satellite data. To maximize the

  9. Chesapeake bay basinwide toxics reduction strategy: an agreement commitment report from the Chesapeake Executive Council. Final report

    SciTech Connect

    Not Available

    1988-07-01

    Outlines steps to be taken to work towards a toxics-free Chesapeake Bay by eliminating the discharge of toxic substances from all controllable sources. Commitments in the strategy are to ensure that by the year 2000 the input of toxic substances from all controllable sources to the Chesapeake Bay will be reduced to levels that result in no toxic or bioaccumulative impacts on the living resources that inhabit the Bay or on human health.

  10. Technical Support Documents Used to Develop the Chesapeake Bay TMDL

    EPA Pesticide Factsheets

    The Chesapeake Bay TMDL development was supported by several technical documents for water quality standards and allocation methodologies specific to the Chesapeake Bay. This page provides the technical support documents.

  11. A pollution history of Chesapeake Bay

    USGS Publications Warehouse

    Goldberg, E.D.; Hodge, V.; Koide, M.; Griffin, J.; Gamble, E.; Bricker, O.P.; Matisoff, G.; Holdren, G.R.; Braun, R.

    1978-01-01

    Present day anthropogenic fluxes of some heavy metals to central Chesapeake Bay appear to be intermediate to those of the southern California coastal region and those of Narragansett Bay. The natural fluxes, however, are in general higher. On the bases of Pb-210 and Pu-239 + 240 geochronologies and of the time changes in interstitial water compositions, there is a mixing of the upper 30 or so centimeters of the sediments in the mid-Chesapeake Bay area through bioturbation by burrowing mollusks and polychaetes. Coal, coke and charcoal levels reach one percent or more by dry weight in the deposits, primarily as a consequence of coal mining operations. ?? 1978.

  12. Turning the tide: Saving the Chesapeake Bay

    SciTech Connect

    Horton, T.; Eichbaum, W.

    1991-07-01

    The Chesapeake Bay is one of the most productive and important ecosystems on earth, and as such is a model for other estuaries facing the demands of commerce, tourism, transportation, recreation, and other uses. This book presents a comprehensive look at two decades of efforts to save the bay, outlining which methods have worked and which have not.

  13. Ecology of the red-tide dinoflagellate Ceratium furca: distribution, mixotrophy, and grazing impact on ciliate populations of Chesapeake Bay.

    PubMed

    Smalley, Gabriela W; Coats, D Wayne

    2002-01-01

    Ceratium furca is a primarily photosynthetic dinoflagellate also capable of ingesting other protists. During 1995 and 1996, we documented the abundance of C. furca in Chesapeake Bay and determined grazing rates on prey labeled with fluorescent microspheres. Abundance usually remained below 20 cells ml(-1), although the species was capable of localized late-summer blooms (< or = 478 cells ml(-1)) in the more saline lower to mid-Bay region. Feeding rates ranged from 0 to 0.11 prey dinoflagellate(-1) h(-1) or from 0 to 37 pg C dinoflagellate(-1) h(-1) and were highest at lower salinities. Clearance rates averaged 2.5 +/- 0.35 microl dinoflagellate(-1) h(-1). Impact of C. furca feeding on prey populations was higher in the lower Bay, averaging 67% of Strobilidium spp. removed d(-1). Ingestion rates were positively correlated with prey abundance and dissolved inorganic nitrogen, but negatively with salinity, depth, dissolved inorganic phosphorus, and inorganic P:N ratio. Daily consumption of prey biomass by C. furca averaged 4.6% of body carbon, 6.5% of body nitrogen, and 4.0% of body phosphorus. with maximal values of 36, 51, and 32%, respectively. Thus, the ability to exploit an organic nutrient source when inorganic nutrients are limiting may give C. furca a competitive advantage over purely photosynthetic species.

  14. Linking public health and the health of the Chesapeake Bay.

    PubMed

    Burke, T A; Litt, J S; Fox, M A

    2000-02-01

    The Chesapeake Bay has a profound impact on the lives of all who reside in the 64,000 square miles of its watershed. From crab cakes to sail-boats, drinking water to naval ships, the Bay touches virtually every aspect of life in the region. The Bay has inspired literature, driven the regional economy, and shaped political decision making and development patterns for homes, industry, agriculture, and transportation. As population demands increase and urban boundaries expand into pristine landscapes, the sustainability of the Chesapeake Bay and its resources face unprecedented pressures. Consequently, the public's health also is vulnerable to Bay pollution and other stresses stemming from development activities and widespread growth occurring throughout the Chesapeake Bay watershed. This paper will examine the linkages between the environmental quality of the Bay and the population health status, recommend ways to bridge ecological and human health concerns in the context of the Bay, and finally present a framework for developing a public health report card for the Bay. Copyright 2000 Academic Press.

  15. Linking public health and the health of the Chesapeake Bay

    SciTech Connect

    Burke, T.A.; Litt, J.S.; Fox, M.A.

    2000-02-01

    The Chesapeake Bay has a profound impact on the lives of all who reside in the 64,000 square miles of its watershed. From crab cakes to sailboats, drinking water to naval ships, the Bay touches virtually every aspect of life in the region. The Bay has inspired literature, driven the regional economy, and shaped political decision making and development patterns for homes, industry, agriculture, and transportation. As population demands increase and urban boundaries expand into pristine landscapes, the sustainability of the Chesapeake Bay and its resources face unprecedented pressures. Consequently, the public's health also is vulnerable to Bay pollution and other stresses stemming from development activities and widespread growth occurring throughout the Chesapeake Bay watershed. This paper will examine the linkages between the environmental quality of the Bay and the population health status, recommend ways to bridge ecological and human health concerns in the context of the Bay, and finally present a framework for developing a public health report card for the Bay.

  16. Coastal and wetland ecosystems of the Chesapeake Bay watershed: Applying palynology to understand impacts of changing climate, sea level, and land use

    USGS Publications Warehouse

    Willard, Debra A.; Bernhardt, Christopher E.; Hupp, Cliff R.; Newell, Wayne

    2015-01-01

    The mid-Atlantic region and Chesapeake Bay watershed have been influenced by fluctuations in climate and sea level since the Cretaceous, and human alteration of the landscape began ~12,000 years ago, with greatest impacts since colonial times. Efforts to devise sustainable management strategies that maximize ecosystem services are integrating data from a range of scientific disciplines to understand how ecosystems and habitats respond to different climatic and environmental stressors. Palynology has played an important role in improving understanding of the impact of changing climate, sea level, and land use on local and regional vegetation. Additionally, palynological analyses have provided biostratigraphic control for surficial mapping efforts and documented agricultural activities of both Native American populations and European colonists. This field trip focuses on sites where palynological analyses have supported efforts to understand the impacts of changing climate and land use on the Chesapeake Bay ecosystem.

  17. Habitat requirements for Chesapeake Bay living resources. Chesapeake Bay Program Agreement Commitment Report

    SciTech Connect

    Not Available

    1988-01-01

    This report provides guidance, along with EPA Water Quality Criteria and State Water Quality Standards and other information, to help refine and improve Chesapeake Bay Agreement programs designed to provide for the restoration and protection of living resources, their habitats, and ecological relationships. The Living Resources Task Force, an ad hoc workgroup of the Chesapeake Bay Program, was charged by the Chesapeake Bay Implementation Committee to develop an approach to define habitat objectives for the living resources of the Bay. The report was produced by the Task Force to establish a technically defensible approach in setting regional habitat objectives for Chesapeake Bay by initially assembling habitat requirement for individual target species. It summarizes the results of the Task Force efforts to date and provides the basis for future refinement of the habitat objectives approach.

  18. Beautiful New Landsat Mosaic of Chesapeake Bay

    NASA Image and Video Library

    2017-09-27

    Aug 30, 2011 USGS has released a new mosaic of the Chesapeake Bay. Using six Landsat 5 images collected in July 2009 and 2011 a beautiful, seamless mosaic of the Chesapeake Bay region was created by the USGS Landsat team. The Washington D.C.-Baltimore-Philadelphia-New York City corridor can be clearly seen (look for silvery purple) as can the Chesapeake and Delaware Bays and the coastal Atlantic barrier islands from Fishermans Island, Virginia to Sandy Hook, New Jersey. To download the full high res go to: landsat.gsfc.nasa.gov/news/news-archive/news_0387.html Credit: NASA/USGS/Landsat 5 NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  19. Chesapeake Bay Program Water Quality Database

    EPA Pesticide Factsheets

    The Chesapeake Information Management System (CIMS), designed in 1996, is an integrated, accessible information management system for the Chesapeake Bay Region. CIMS is an organized, distributed library of information and software tools designed to increase basin-wide public access to Chesapeake Bay information. The information delivered by CIMS includes technical and public information, educational material, environmental indicators, policy documents, and scientific data. Through the use of relational databases, web-based programming, and web-based GIS a large number of Internet resources have been established. These resources include multiple distributed on-line databases, on-demand graphing and mapping of environmental data, and geographic searching tools for environmental information. Baseline monitoring data, summarized data and environmental indicators that document ecosystem status and trends, confirm linkages between water quality, habitat quality and abundance, and the distribution and integrity of biological populations are also available. One of the major features of the CIMS network is the Chesapeake Bay Program's Data Hub, providing users access to a suite of long- term water quality and living resources databases. Chesapeake Bay mainstem and tidal tributary water quality, benthic macroinvertebrates, toxics, plankton, and fluorescence data can be obtained for a network of over 800 monitoring stations.

  20. Status and Assessment of Chesapeake Bay Wildlife Contamination

    USGS Publications Warehouse

    Heinz, G.H.; Wiemeyer, Stanley N.; Clark, D.R.; Albers, P.H.; Henry, P.; Batiuk, R.A.

    1992-01-01

    As an integral component of its priority setting process, the Chesapeake Bay Program`s Toxics Subcommittee has sought the expertise of Chesapeake Bay researchers and managers in developing a series of Chesapeake Bay toxics status and assessment papers. In the report, evidence for historical and current contaminant effects on key bird species, mammals, reptiles and amphibians which inhabit the Chesapeake Bay basin is examined. For each group of wildlife species, a general overview of effects caused by specific toxic substances is followed by detailed accounts of contaminant effects on selected species. Sponsored by Environmental Protection Agency, Annapolis, MD. Chesapeake Bay Program.

  1. Metaproteomic analysis of Chesapeake Bay microbial communities

    PubMed Central

    Kan, Jinjun; Hanson, Thomas E; Ginter, Joy M; Wang, Kui; Chen, Feng

    2005-01-01

    Background Natural microbial communities are extremely complex and dynamic systems in terms of their population structure and functions. However, little is known about the in situ functions of the microbial communities. Results This study describes the application of proteomic approaches (metaproteomics) to observe expressed protein profiles of natural microbial communities (metaproteomes). The technique was validated using a constructed community and subsequently used to analyze Chesapeake Bay microbial community (0.2 to 3.0 μm) metaproteomes. Chesapeake Bay metaproteomes contained proteins from pI 4–8 with apparent molecular masses between 10–80 kDa. Replicated middle Bay metaproteomes shared ~92% of all detected spots, but only shared 30% and 70% of common protein spots with upper and lower Bay metaproteomes. MALDI-TOF analysis of highly expressed proteins produced no significant matches to known proteins. Three Chesapeake Bay proteins were tentatively identified by LC-MS/MS sequencing coupled with MS-BLAST searching. The proteins identified were of marine microbial origin and correlated with abundant Chesapeake Bay microbial lineages, Bacteroides and α-proteobacteria. Conclusion Our results represent the first metaproteomic study of aquatic microbial assemblages and demonstrate the potential of metaproteomic approaches to link metagenomic data, taxonomic diversity, functional diversity and biological processes in natural environments. PMID:16176596

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

    DTIC Science & Technology

    1984-10-01

    block number) FIELD GROUP SUB-GROUP James River, lower Chesapeake Bay, physical model test, en- vironmental impact, habitat loss/gain, hydrodynamic...Organisms ......................... 32 *Results of the Physical Model Test ..... 4* ......... 0.0-........ 34 Determination of Threshold of "Significant...Term Average 27 and Model Hydrograph Isohalines for the James River ". . 4:i Ip * . *. "* - V, APPENDIX A Description of Study Species Page Chrysaora

  3. High-resolution seismic reflection/refraction images near the outer margin of the Chesapeake Bay impact crater, York-James Peninsula, southeastern Virginia

    USGS Publications Warehouse

    Catchings, R.D.; Saulter, D.E.; Powars, D.S.; Goldman, M.R.; Dingler, J.A.; Gohn, G.S.; Schindler, J.S.; Johnson, G.H.

    2001-01-01

    Powars and Bruce (1999) showed that the Chesapeake Bay region of southeastern Virginia was the site of an asteroid or comet impact during the late Eocene, approximately 35 million years ago (Fig. 1). Initial borehole and marine seismic-reflection data revealed a 90-km-diameter impact structure, referred to as the Chesapeake Bay Impact Crater (CBIC), that lies buried beneath the southern Chesapeake Bay and surrounding Virginia Coastal Plain (Powars and Bruce, Figs. 1b). Stratigraphic correlations among a series of boreholes suggest that the impact disrupted basement rock and the overlying Cretaceous through middle Eocene deltaic and marine sediments. The CBIC truncates important regional sedimentary aquifer systems and possibly caused differential flushing of connate seawater. Therefore, the CBIC affects the present-day ground-water quantity and quality in the rapidly growing Hampton Roads region of southeastern Virginia. Impact-generated faults in the basement rock may be the sources of small-to-moderate earthquakes that have been occurred around the perimeter of the impact structure over the past few hundred years (Johnson et al., 1998). Powars and Bruce (1999) suggest that 150 m to 490 m of relatively undisturbed, post-impact Coastal-Plain sediments overlie the impact-disrupted sediments and basement rocks west of Chesapeake Bay. Their interpretation of marine seismic data, released from Texaco and Exxon, revealed a central 38-km-wide, 1.6-km-deep disrupted zone in the basement rocks (inner basin), which is surrounded by a 21- to 31-km-wide, 1- km-deep annular trough. Steep rim escarpments surround these features, which they mapped regionally as the outer and inner margins (rims) of the CBIC (Fig. 1b). The outer margin is a slumped terrace zone that has a 120- to 305-m-high gullied escarpment and varies in width from 0.8 to 3.2 km. However, the geographic bounds of the CBIC, its effects on the regional aquifer systems, and the distribution of impact generated

  4. Chesapeake Bay as seen from STS-58

    NASA Image and Video Library

    1993-10-30

    STS058-81-049 (18 Oct-1 Nov 1993) --- This view encompasses most of the large estuarine system of the Chesapeake Bay. The farmland and marshes of eastern shores of the Chesapeake (eastern Maryland and Virginia) are the foreground. The largest tributary flowing into the Bay is the Potomac River; Washington, D.C. is visible where the river bends to the northwest. The urban-suburban corridor between Washington, D.C. and Baltimore to the north (toward the right on this view) shows well as the gray zone which extends from left (D.C. on the Potomac) to right (Baltimore on the Patapsco River embayment on the Chesapeake, near the upper right).

  5. Comparison of forest area data in the Chesapeake Bay Watershed

    Treesearch

    Tonya W. Lister; Andrew J. Lister

    2012-01-01

    The Chesapeake Bay, the largest estuary in the United States, has been designated by executive order as a national treasure. There is much interest in monitoring the status and trends in forest area within the bay, especially since maintaining forest cover is key to bay restoration efforts. The Chesapeake Bay Land Cover Data Series (CBLCD), a Landsat-based, multi-...

  6. 75 FR 11837 - Chesapeake Bay Watershed Initiative

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-12

    ..., but not exclusive, consideration to producers' applications in the following river basins: Susquehanna River, Shenandoah River, Potomac River (including North and South), and the Patuxent River. The... restore, enhance, and conserve soil, air, and related resources in the Chesapeake Bay watershed...

  7. Jackup rigs in the Chesapeake Bay

    SciTech Connect

    Janaitis, T.W.

    1981-09-01

    The criteria used for selecting a 91 x 91 m offshore site in Chesapeake Bay for constructing a jackup rig which, when completed, will be towed to the Gulf of Mexico, are described, and the successful construction of the rig at the site selected, is discussed. Plans call for 4 more rigs to be constructed at this site. (LCL)

  8. Confirmation of a meteoritic component in impact-melt rocks of the Chesapeake Bay impact structure, Virginia, USA - Evidence from osmium isotopic and PGE systematics

    USGS Publications Warehouse

    Lee, S.R.; Horton, J.W.; Walker, R.J.

    2006-01-01

    The osmium isotope ratios and platinum-group element (PGE) concentrations of impact-melt rocks in the Chesapeake Bay impact structure were determined. The impact-melt rocks come from the cored part of a lower-crater section of suevitic crystalline-clast breccia in an 823 m scientific test hole over the central uplift at Cape Charles, Virginia. The 187Os/188Os ratios of impact-melt rocks range from 0.151 to 0.518. The rhenium and platinum-group element (PGE) concentrations of these rocks are 30-270?? higher than concentrations in basement gneiss, and together with the osmium isotopes indicate a substantial meteoritic component in some impact-melt rocks. Because the PGE abundances in the impact-melt rocks are dominated by the target materials, interelemental ratios of the impact-melt rocks are highly variable and nonchondritic. The chemical nature of the projectile for the Chesapeake Bay impact structure cannot be constrained at this time. Model mixing calculations between chondritic and crustal components suggest that most impact-melt rocks include a bulk meteoritic component of 0.01-0.1% by mass. Several impact-melt rocks with lowest initial 187Os/188Os ratios and the highest osmium concentrations could have been produced by additions of 0.1%-0.2% of a meteoritic component. In these samples, as much as 70% of the total Os may be of meteoritic origin. At the calculated proportions of a meteoritic component (0.01-0.1% by mass), no mixtures of the investigated target rocks and sediments can reproduce the observed PGE abundances of the impact-melt rocks, suggesting that other PGE enrichment processes operated along with the meteoritic contamination. Possible explanations are 1) participation of unsampled target materials with high PGE abundances in the impact-melt rocks, and 2) variable fractionations of PGE during syn- to post-impact events. ?? The Meteoritical Society, 2006.

  9. Confirmation of a meteoritic component in impact-melt rocks of the Chesapeake Bay impact structure, Virginia, USA - Evidence from osmium isotopic and PGE systematics

    NASA Astrophysics Data System (ADS)

    Lee, Seung Ryeol; Horton, J. Wright; Walker, Richard J.

    2006-06-01

    The osmium isotope ratios and platinum-group element (PGE) concentrations of impact-melt rocks in the Chesapeake Bay impact structure were determined. The impact-melt rocks come from the cored part of a lower-crater section of suevitic crystalline-clast breccia in an 823 m scientific test hole over the central uplift at Cape Charles, Virginia. The 187Os/188Os ratios of impact-melt rocks range from 0.151 to 0.518. The rhenium and platinum-group element (PGE) concentrations of these rocks are 30-270× higher than concentrations in basement gneiss, and together with the osmium isotopes indicate a substantial meteoritic component in some impact-melt rocks. Because the PGE abundances in the impact-melt rocks are dominated by the target materials, interelemental ratios of the impact-melt rocks are highly variable and nonchondritic. The chemical nature of the projectile for the Chesapeake Bay impact structure cannot be constrained at this time. Model mixing calculations between chondritic and crustal components suggest that most impact-melt rocks include a bulk meteoritic component of 0.01-0.1% by mass. Several impact-melt rocks with lowest initial 187Os/188Os ratios and the highest osmium concentrations could have been produced by additions of 0.1%-0.2% of a meteoritic component. In these samples, as much as 70% of the total Os may be of meteoritic origin. At the calculated proportions of a meteoritic component (0.01-0.1% by mass), no mixtures of the investigated target rocks and sediments can reproduce the observed PGE abundances of the impact-melt rocks, suggesting that other PGE enrichment processes operated along with the meteoritic contamination. Possible explanations are 1) participation of unsampled target materials with high PGE abundances in the impact-melt rocks, and 2) variable fractionations of PGE during syn- to post-impact events.

  10. Chesapeake Bay area nutrient management programs: An overview. chesapeake bay program technology transfer report

    SciTech Connect

    1996-03-01

    Agriculture has been identified as a major contributor of nutrients to the Chesapeake Bay in the 1987 Chesapeake Bay Agreement. Under this agreement, the states of Maryland, Pennsylvania, and Virginia and the District of Columbia committed to reduce nutrient loads to the Chesapeake Bay by 40 percent by the year 2000. These jurisdictions have made the implementation of agricultural nonpoint source (NPS) pollution control effective practice to reduce NPS pollution in the 1992 Baywide Nutrient Reduction Reevaluation and the 1995 `Cost Analysis for Nonpoint Source Control Strategies in the Chesapeake Basin`. Nutrient management is a pollution prevention practice that manages the rate, timing, and method of application of nutrients and minimizes their potential losses through runoff or leaching to groundwater. Nitrogen, phosphorus and potassium are three essential plant nutrients used in significant amounts in intensive agricultural operations. These nutrients are important for satisfactory crop production but, if not managed properly, can easily move from farmland to ground and surface waters.

  11. Predictability of Vibrio cholerae in Chesapeake Bay

    PubMed Central

    Louis, Valérie R.; Russek-Cohen, Estelle; Choopun, Nipa; Rivera, Irma N. G.; Gangle, Brian; Jiang, Sunny C.; Rubin, Andrea; Patz, Jonathan A.; Huq, Anwar; Colwell, Rita R.

    2003-01-01

    Vibrio cholerae is autochthonous to natural waters and can pose a health risk when it is consumed via untreated water or contaminated shellfish. The correlation between the occurrence of V. cholerae in Chesapeake Bay and environmental factors was investigated over a 3-year period. Water and plankton samples were collected monthly from five shore sampling sites in northern Chesapeake Bay (January 1998 to February 2000) and from research cruise stations on a north-south transect (summers of 1999 and 2000). Enrichment was used to detect culturable V. cholerae, and 21.1% (n = 427) of the samples were positive. As determined by serology tests, the isolates, did not belong to serogroup O1 or O139 associated with cholera epidemics. A direct fluorescent-antibody assay was used to detect V. cholerae O1, and 23.8% (n = 412) of the samples were positive. V. cholerae was more frequently detected during the warmer months and in northern Chesapeake Bay, where the salinity is lower. Statistical models successfully predicted the presence of V. cholerae as a function of water temperature and salinity. Temperatures above 19°C and salinities between 2 and 14 ppt yielded at least a fourfold increase in the number of detectable V. cholerae. The results suggest that salinity variation in Chesapeake Bay or other parameters associated with Susquehanna River inflow contribute to the variability in the occurrence of V. cholerae and that salinity is a useful indicator. Under scenarios of global climate change, increased climate variability, accompanied by higher stream flow rates and warmer temperatures, could favor conditions that increase the occurrence of V. cholerae in Chesapeake Bay. PMID:12732548

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

    USGS Publications Warehouse

    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

  13. Osmium-isotope Evidence for a Projectile Component in Impact-melt Rocks, Chesapeake Bay Impact Structure, Virginia, USA

    NASA Astrophysics Data System (ADS)

    Lee, S.; Horton, J. W.; Walker, R. J.

    2004-12-01

    The late Eocene Chesapeake Bay impact structure (CBIS) is preserved beneath post-impact sediments on the Atlantic margin of Virginia. This 85-km-diameter complex crater formed on the continental shelf of a passive margin in a layered target consisting of ocean water, Cretaceous and Tertiary sediments (mainly siliciclastic), and crystalline basement rocks. The basement rocks include Neoproterozoic granitoids and felsite as well as gneiss of undetermined age. In May, 2004, the USGS drilled an 823-m test hole in the central uplift of the CBIS at Cape Charles, Va., providing drill cuttings and limited core. The core from 744 to 823 m depth contains crystalline-clast breccia and brecciated gneiss that are distinct from sediment-clast breccias recovered from coreholes in the annular trough of the CBIS. Rocks interpreted to be impact-melt clasts and dikes in the crystalline-clast breccia were sampled for analyses of osmium (Os) concentrations and 187Os/188Os ratios to test for evidence of the projectile. These analyses were conducted on samples from a dike (aphanitic to partly hyaline, ST2440.8C) within a gneissic block, from a block of holocrystalline mafic rock (aphanitic, ST2453.3C), and from a flow-laminated bomb (aphanitic to partly hyaline, ST2570.0C). The Os concentrations and 187Os/188Os ratios for samples ST2440.8C, ST2453.3C and ST2570.0C are 0.928, 0.711 and 0.312 ppb, and 0.15205, 0.15545 and 0.22345, respectively. These values are much higher (Os) or lower (187Os/188Os) than those reported for rocks of the upper continental crust, suggesting a significant contribution of osmium from the projectile in these impact-melt rocks. Moreover, a strong negative correlation between 187Os/188Os and Os for these samples suggests that it may be possible to use mixing curves to calculate the proportions of projectile and target-rock components. Our results from the CBIS contrast with those from the Chicxulub crater, where there is little or no evidence for the

  14. Crystalline Basement and Impact-Derived Clasts from Three Coreholes in the Chesapeake Bay Impact Structure, Southeastern Virginia

    NASA Astrophysics Data System (ADS)

    Horton, J. W.; Aleinikoff, J. N.; Izett, G. A.; Naeser, N. D.; Naeser, C. W.; Kunk, M. J.

    2002-05-01

    Three recent coreholes in the late Eocene (35.3 Ma) Chesapeake Bay impact structure of the Coastal Plain in southeastern Virginia recovered samples of crystalline basement and reworked impact ejecta. The corehole at NASA Langley near Hampton, and two others (at North and Bayside) in eastern Matthews Co., are in the annular trough about 19, 24, and 8 km, respectively, outside the rim of the inner basin of the structure. Each corehole has a complete section of the Exmore diamicton that overlies impact-disturbed Cretaceous sediments of the Coastal Plain. Most crystalline clasts in the diamicton and underlying sediments are rounded, are assumed to be detrital, and were not studied. More angular clasts were selected and examined for impact-derived features. Some clasts have cataclastic fabric in which shock-metamorphosed quartz is an integral part. Shocked quartz is present, but sparse, in a few clasts in all three cores. Shocked plagioclase and potassium feldspar are present in a peculiar igneous clast (altered monzonite?) in the Bayside core. The suite of clasts interpreted to be ejecta-derived includes granitoid, other plutonic rock, and variably porphyritic felsite. A cataclastically deformed granophyric leucogranite clast in the Exmore diamicton has a preliminary SHRIMP U-Pb zircon age of 87 +/- 1 Ma. This surprising age is unprecedented in the eastern United States and suggests derivation from a plutonic source related to offshore, post-rift Cretaceous intrusions and seamounts. Crystalline basement below the sedimentary section has been recovered in the Langley core from 626.3 m (top) to 635.1 m (total depth) and in the Bayside core from 708.9 m (top) to 728.5 m (total depth). Basement rocks in both cores are pale red, medium-grained monzogranites that are non-foliated and highly chloritized. Chlorite is the principal mafic mineral in the granites, and at Bayside traces of relict biotite remain. The top of the granite in each core is weathered but not saprolitized

  15. Chesapeake Bay sediment flux model. Final report

    SciTech Connect

    Di Toro, D.M.; Fitzpatrick, J.J.

    1993-06-01

    Formulation and application of a predictive diagenetic sediment model are described in this report. The model considers two benthic sediment layers: a thin aerobic layer in contact with the water column and a thicker anaerobic layer. Processes represented include diagenesis, diffusion, particle mixing, and burial. Deposition of organic matter, water column concentrations, and temperature are treated as independent variables that influence sediment-water fluxes. Sediment oxygen demand and sediment-water fluxes of sulfide, ammonium, nitrate, phosphate, and silica are predicted. The model was calibrated using sediment-water flux observations collected in Chesapeake Bay 1985-1988. When independent variables were specified based on observations, the model correctly represented the time series of sediment-water fluxes observed at eight stations in the Bay and tributaries.... Chesapeake Bay, Models, Sediments, Dissolved oxygen, Nitrogen Eutrophication, Phosphorus.

  16. Hydraulic Control and Mixing in Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Ott, M. W.

    2006-05-01

    Properly modeling the exchange rate at the mouths of estuarine bays is critical to understanding the effects of freshwater and pollutants on the hydrographic and biological conditions within these bays. There is evidence that hydraulic control occurs at certain locations in the deeper channels of Chesapeake Bay and may be a mechanism in limiting the exchange rate. In addition, the vertical and horizontal mixing associated with the resulting hydraulic jumps has implications both for the hydrographic conditions and circulation, as well as for primary productivity within Chesapeake Bay. Shipboard acoustic Doppler current profiler (ADCP) data, as well as conductivity-temperature-depth (CTD) profiles were collected during the spring of 2005 at various locations within Chesapeake Bay to better understand the occurrence and strength of hydraulic controls in relation to the phases of the fortnightly and semi-diurnal tidal cycles as well as to topography. Mixing is shown to occur alternatively over both hollows and bumps, depending on the tidal phase, and the strength and effects if this mixing is compared.

  17. Mycobacteria isolated from Chesapeake Bay fish.

    PubMed

    Stine, C B; Kane, A S; Baya, A M

    2010-01-01

    Mycobacteriosis in fish can result in ulcers, emaciation, and in some cases death. Mycobacteria have been previously isolated from a variety of Chesapeake Bay fish species, and the current study was designed to identify potential host specificity and location fidelity of mycobacterial isolates. Mycobacteria were isolated from wild fish of the Chesapeake Bay collected from the Upper Bay, the Choptank River, Herring Bay, the Chicamacomico River, the Pocomoke River and the Potomac River in 2003-2006. Mycobacterial isolates were recovered from striped bass, Morone saxatilis, Atlantic menhaden, Brevoortia tyrannus, white perch, Morone americana, summer flounder, Paralichthys dentatus, spot, Leiostomus xanthurus, largemouth bass, Micropterus salmoides, channel catfish, Ictalurus punctatus, common carp, Cyprinus carpio carpio, spotted seatrout, Cynoscion nebulosus, killifish, Fundulus sp., blueback herring, Alosa aestivalis, American gizzard shad, Dorosoma cepedianum and American silver perch, Bairdiella chrysoura. Twenty-nine well-defined mycobacterial groups resulted from gas chromatography dendrogram clustering of isolates. The majority of groups included more than one host species and more than one site of collection. However, four groups contained only striped bass isolates, three of which were similar to M. shottsii. Therefore, multiple Chesapeake Bay fish species are colonized with multiple mycobacterial isolates, of which few appear to be host or location specific.

  18. Long-term history of Chesapeake Bay anoxia

    SciTech Connect

    Cooper, S.R.; Brush, G.S. )

    1991-11-15

    Stratigraphic records from four sediment cores collected along a transect across the Chesapeake Bay near the mouth of the Choptank River were used to reconstruct a 2,000-year history of anoxia and eutrophication in the Chesapeake Bay. Variations in pollen, diatoms, concentration of organic carbon, nitrogen, sulfur, acid-soluble iron, and an estimate of the degree of pyritization of iron indicate that sedimentation rates, anoxic conditions and eutrophication have increased in the Chesapeake Bay since the time of European settlement.

  19. 46 CFR 7.50 - Chesapeake Bay and tributaries.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Chesapeake Bay and tributaries. 7.50 Section 7.50... Atlantic Coast § 7.50 Chesapeake Bay and tributaries. A line drawn from Cape Charles Light to latitude 36... latitude 36°54.8′ N. longitude 75°55.6′ W. (Chesapeake Bay Entrance Lighted Bell Buoy “CBC”); thence to...

  20. 46 CFR 7.50 - Chesapeake Bay and tributaries.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Chesapeake Bay and tributaries. 7.50 Section 7.50... Atlantic Coast § 7.50 Chesapeake Bay and tributaries. A line drawn from Cape Charles Light to latitude 36... latitude 36°54.8′ N. longitude 75°55.6′ W. (Chesapeake Bay Entrance Lighted Bell Buoy “CBC”); thence to...

  1. 46 CFR 7.50 - Chesapeake Bay and tributaries.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Chesapeake Bay and tributaries. 7.50 Section 7.50... Atlantic Coast § 7.50 Chesapeake Bay and tributaries. A line drawn from Cape Charles Light to latitude 36... latitude 36°54.8′ N. longitude 75°55.6′ W. (Chesapeake Bay Entrance Lighted Bell Buoy “CBC”); thence to...

  2. Status and assessment of Chesapeake Bay wildlife contamination

    SciTech Connect

    Heinz, G.H.; Wiemeyer, S.N.; Clark, D.R.; Albers, P.; Henry, P.

    1992-10-01

    As an integral component of its priority setting process, the Chesapeake Bay Program's Toxics Subcommittee has sought the expertise of Chesapeake Bay researchers and managers in developing a series of Chesapeake Bay toxics status and assessment papers. In the report, evidence for historical and current contaminant effects on key bird species, mammals, reptiles and amphibians which inhabit the Chesapeake Bay basin is examined. For each group of wildlife species, a general overview of effects caused by specific toxic substances is followed by detailed accounts of contaminant effects on selected species.

  3. Modeling nitrogen cycling in forested watersheds of Chesapeake Bay

    SciTech Connect

    Hunsaker, C.T.; Garten, C.T.; Mulholland, P.J.

    1995-03-01

    The Chesapeake Bay Agreement calls for a 40% reduction of controllable phosphorus and nitrogen to the tidal Bay by the year 2000. To accomplish this goal the Chesapeake Bay Program needs accurate estimates of nutrient loadings, including atmospheric deposition, from various land uses. The literature was reviewed on forest nitrogen pools and fluxes, and nitrogen data from research catchments in the Chesapeake Basin were identified. The structure of a nitrogen module for forests is recommended for the Chesapeake Bay Watershed Model along with the possible functional forms for fluxes.

  4. Understanding food webs in the Chesapeake Bay

    USGS Publications Warehouse

    Keough, J.R.; Haramis, G.M.; Perry, M.C.; Perry, M.C.

    2002-01-01

    Approaches to predictive modeling and to management of the Chesapeake Bay ecosystem are 'bottom up' (i.e., approaches involve the control of nutrient inputs in attempts to manage plankton productivity) and 'top down' (i.e., approaches involve controls on harvest of fisheries and wildlife in attempts to manage vertebrate populations). Both approaches are limited by a lack of understanding of trophic connections between nutrient inputs, primary producers, and higher trophic level consumers. This project is aimed at identifying trophic structure for the submersed aquatic vegetation habitat of the Chesapeake Bay. We are employing analysis of stable isotope ratios of plant and animal tissues to identify trophic levels and traditional food habits analysis to identify the foods of a number of species of waterfowl.

  5. Hydraulic model of the Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Robinson, A. E., Jr.

    1978-01-01

    Preliminary planning for the formulation of the first year of hydraulic studies on the Chesapeake Bay model was recently completed. The primary purpose of this initial effort was to develop a study program that is both responsive to problems of immediate importance and at the same time ensure that from the very beginning of operation maximum economical use is made of the model. The formulation of this preliminary study plan involved an extensive analysis of the environmental, economic, and social aspects of a series of current problems in order to establish a priority listing of their importance. The study program that evolved is oriented towards the analysis of the effects of some of the works of man on the Chesapeake Bay estuarine environment.

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

    USGS Publications Warehouse

    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.

  7. Integrated sequence stratigraphy of the postimpact sediments from the Eyreville core holes, Chesapeake Bay impact structure inner basin

    USGS Publications Warehouse

    Browning, J.V.; Miller, K.G.; McLaughlin, P.P.; Edwards, L.E.; Kulpecz, A.A.; Powars, D.S.; Wade, B.S.; Feigenson, M.D.; Wright, J.D.

    2009-01-01

    The Eyreville core holes provide the first continuously cored record of postimpact sequences from within the deepest part of the central Chesapeake Bay impact crater. We analyzed the upper Eocene to Pliocene postimpact sediments from the Eyreville A and C core holes for lithology (semiquantitative measurements of grain size and composition), sequence stratigraphy, and chronostratigraphy. Age is based primarily on Sr isotope stratigraphy supplemented by biostratigraphy (dinocysts, nannofossils, and planktonic foraminifers); age resolution is approximately ??0.5 Ma for early Miocene sequences and approximately ??1.0 Ma for younger and older sequences. Eocene-lower Miocene sequences are subtle, upper middle to lower upper Miocene sequences are more clearly distinguished, and upper Miocene- Pliocene sequences display a distinct facies pattern within sequences. We recognize two upper Eocene, two Oligocene, nine Miocene, three Pliocene, and one Pleistocene sequence and correlate them with those in New Jersey and Delaware. The upper Eocene through Pleistocene strata at Eyreville record changes from: (1) rapidly deposited, extremely fi ne-grained Eocene strata that probably represent two sequences deposited in a deep (>200 m) basin; to (2) highly dissected Oligocene (two very thin sequences) to lower Miocene (three thin sequences) with a long hiatus; to (3) a thick, rapidly deposited (43-73 m/Ma), very fi ne-grained, biosiliceous middle Miocene (16.5-14 Ma) section divided into three sequences (V5-V3) deposited in middle neritic paleoenvironments; to (4) a 4.5-Ma-long hiatus (12.8-8.3 Ma); to (5) sandy, shelly upper Miocene to Pliocene strata (8.3-2.0 Ma) divided into six sequences deposited in shelf and shoreface environments; and, last, to (6) a sandy middle Pleistocene paralic sequence (~400 ka). The Eyreville cores thus record the fi lling of a deep impact-generated basin where the timing of sequence boundaries is heavily infl uenced by eustasy. ?? 2009 The Geological

  8. Satellite Maps Show Chesapeake Bay Urban Development

    NASA Astrophysics Data System (ADS)

    Goetz, Scott J.; Jantz, Patrick

    2006-04-01

    The extent, density, and configuration of the built environment-such as buildings, roads, parking lots, and other materials constructed for human use-have an impact on a wide range of biogeochemical and hydrological processes. These built areas, which are impervious to water infiltration, modify hydrology through the combined influence of increased peak flows, reduced base flows, flashier stream hydrographs (decreased lag times between storm events and peak discharge), and changes in bank and streambed erosion [Nilsson et al., 2003]. Additionally, increasing impervious cover has long been known to amplify point source pollution discharges into streams, including chemical runoff from parking lots and roads [Schueler, 1994]. Two maps of the built environment, expressed in terms of impervious surface area, have been derived for areas that encompass the 168,000-square kilometer Chesapeake Bay watershed (Figure 1), a region that has been highly altered by human land use [Goetz et al., 2004; Jantz et al., 2005]. One map was developed for the region at fine (30-square-meter) spatial resolution, and the other covers the extent of the conterminous United States at one-square-kilometer resolution [Elvidge et al., 2004]. A finer-resolution regional map was used to assess the quality of the national map, demonstrating the utility the latter map for a range of applications related to monitoring land transformation and assessing watershed impacts.

  9. Late Quaternary history of southern Chesapeake Bay

    SciTech Connect

    Colman, S.M.; Hobbs, C.H. III; Halka, J.P.

    1985-01-01

    More than 700 km of high-resolution, seismic-reflection profiles and sidescan-sonar images provide new information about the late Quaternary history of southern Chesapeake Bay. Sidescan-sonar images show that, excluding the nearshore zone, most of the bay bottom has a monotonously smooth surface, except that sand waves, ripples, and other bedforms occur in local areas affected by tidal currents. Seismic-reflection data show that the Quaternary stratigraphy of the southern part of the Bay is related primarily to the last cycle of sea-level change. The Quaternary section overlies an erosion surface cut deeply into gently seaward-dipping marine beds of Neogene age. Fluvial paleochannels, related to the last major low sea-level stand, are characterized by as much as 55 m of incision and by thin, irregular, terrace and channel-bottom deposits. Marine and estuarine deposits related to the Holocene transgression partially or fully bury the fluvial valleys and overlie the interfluves. A prominent feature of the Bay-mouth area is a wedge of sediment that has prograded into the Bay from the inner shelf. The common assumption--that the Chesapeake Bay is the drowned valley of the Pleistocene Susquehanna River--is only partially valid for the southern part of the Bay. The Bay mouth area, in general, is relatively young. The axial channel of the Bay is a modern tidal channel that is actively eroding Tertiary deposits and migrating toward the south and west; it is unrelated to older fluvial channels. Also, the positions of the modern axial channel and the last two fluvial paleochannels indicate long-term southward migration of the Bay mouth.

  10. High-Resolution Seismic Reflection Survey of the Southwestern Margin of the Chesapeake Bay Impact Structure, Virginia

    NASA Astrophysics Data System (ADS)

    Catchings, R. D.; Powars, D. S.; Gohn, G. S.; Goldman, M. R.

    2002-05-01

    The late Eocene Chesapeake Bay impact structure is a buried, 90-km-wide, "wet-target," complex crater situated in the eastern Virginia Coastal Plain. A high-resolution seismic reflection survey across the crater's southwestern margin on the lower York-James Peninsula is tied to the core samples and sonic velocity log from a 635-m-deep corehole that reached crystalline basement rocks at the NASA Langley Research Center, Hampton, VA. The seismic transect was 13.6 km long although data gaps reduced the actual survey distance to about 9.0 km. Acquisition parameters included: 5-m spacing for the seisgun source and geophones; 25-m spacing for the explosive source (0.11 kg of ammonium nitrate); and four 60-channel seismographs. Time-distance, depth-distance, and migrated depth-distance images were generated. Preliminary analysis of the seismic images indicates a good correlation between the core stratigraphy and the seismic stratigraphy within the crater's outer annular trough. Granitic basement and overlying sections of impact-modified Cretaceous and lower Tertiary sediments, impact-generated sediments, and post-impact sediments have distinctive seismic signatures. At Langley, thick high-amplitude reflections represent the top of basement near 625 m depth, in good agreement with the corehole; this seismic signature is readily traced across the entire survey. Relief on the basement top approaches 200 m, and numerous diffractions on the unmigrated images indicate that the basement rock is highly fractured. Moderately continuous, horizontal to locally inclined reflections characterize the unshocked, locally fluidized, parauthochthonous Cretaceous sediments in the lower part of the sedimentary section above basement. These reflections are broken by pervasive, subvertical, small-offset faults that are well displayed on the migrated depth section. Higher in the sedimentary section, strongly faulted and fluidized Cretaceous and lower Tertiary sediments are represented by

  11. Geologic Constraints on Modeling of Complex-Crater Collapse: Data from the Chesapeake Bay Impact Structure, Virginia

    NASA Astrophysics Data System (ADS)

    Gohn, G. S.; Powars, D. S.; Bruce, T. S.; Quick, J. E.; Catchings, R. D.

    2002-05-01

    Numerical models of complex impact-crater collapse frequently invoke Bingham fluids as the rheologic model for the behavior of rocks and sediments surrounding the transient crater during gravity-driven collapse. Acoustic fluidization is increasingly relied on by modelers to produce the necessary reduction in overburden pressure at depth that leads to the transient viscous flow of the Bingham fluid. Geologic and geophysical field studies of the buried, 90-km-wide, late Eocene Chesapeake Bay impact structure (CBIS) (Virginia Coastal Plain) provide constraints for model parameters. The target protolith of the CBIS consisted of Proterozoic and Paleozoic crystalline rocks overlain by hundreds of meters of Cretaceous and Tertiary sediments. The USGS-NASA Langley corehole (Hampton, Va.) and an adjacent high-resolution seismic-reflection survey, both located inside and near the outer margin of the CBIS, reveal the vertical variation in impact disruption within the sedimentary section outside the collapsed transient crater. The observed sediment responses to the impact and their vertical distance above crystalline rock are: deepest fluidization of susceptible sands (68 m); deepest downward infiltration of dissociated Tertiary sediments into Cretaceous sediments (183 m); deepest widespread fluidization, widespread downward infiltration of Tertiary sediments into Cretaceous section, and authigenic resedimentation (198 m); deepest occurrence of sparse shocked ejecta (350 m); inferred position of spall ejection (missing Tertiary sediments) (357 m); base of allogenic resurge deposits (357 m); and top of impactites (391 m). Preliminary analysis of additional cores suggests that these horizons become absolutely and stratigraphically deeper toward the crater's center. The general upward increase in disruption of the impact-modified sedimentary section likely reflects the role of overburden pressure in increasing the Bingham yield stress with depth. The seismic survey shows

  12. Army initiatives in the Chesapeake Bay: Case studies of successful partnerships

    SciTech Connect

    Phelps, S.; Merkel, H.

    1997-08-01

    The Army maintains 19 installations within the Chesapeake Bay watershed. In response to the Bay`s declining water quality and living resources and to the 1983 Chesapeake Bay Agreement which set forth Bay restoration goals and initiatives, the Department of Defense (DoD) became formally involved in the Bay`s restoration effort in 1984 with the signing of the EPA/DoD Chesapeake Bay Initiative--A Joint Resolution on Pollution Abatement in the Chesapeake Bay. This agreement eventually led to the Army`s development of the Chesapeake Bay Initiative (CBI) Program in 1990, which formally organized Army installation efforts in the restoration of the Chesapeake Bay.

  13. Chesapeake bay watershed land cover data series

    USGS Publications Warehouse

    Irani, Frederick M.; Claggett, Peter R.

    2010-01-01

    To better understand how the land is changing and to relate those changes to water quality trends, the USGS EGSC funded the production of a Chesapeake Bay Watershed Land Cover Data Series (CBLCD) representing four dates: 1984, 1992, 2001, and 2006. EGSC will publish land change forecasts based on observed trends in the CBLCD over the coming year. They are in the process of interpreting and publishing statistics on the extent, type and patterns of land cover change for 1984-2006 in the Bay watershed, major tributaries and counties.

  14. Management of Urban Stormwater Runoff in the Chesapeake Bay Watershed

    USGS Publications Warehouse

    Hogan, Dianna M.

    2008-01-01

    Urban and suburban development is associated with elevated nutrients, sediment, and other pollutants in stormwater runoff, impacting the physical and environmental health of area streams and downstream water bodies such as the Chesapeake Bay. Stormwater management facilities, also known as Best Management Practices (BMPs), are increasingly being used in urban areas to replace functions, such as flood protection and water quality improvement, originally performed by wetlands and riparian areas. Scientists from the U.S. Geological Survey (USGS) have partnered with local, academic, and other Federal agency scientists to better understand the effectiveness of different stormwater management systems with respect to Chesapeake Bay health. Management of stormwater runoff is necessary in urban areas to address flooding and water quality concerns. Improving our understanding of what stormwater management actions may be best suited for different types of developed areas could help protect the environmental health of downstream water bodies that ultimately receive runoff from urban landscapes.

  15. Willingness to Pay Survey for Chesapeake Bay Total ...

    EPA Pesticide Factsheets

    A stated preference survey to collect data on households’ use of Chesapeake Bay and its watershed, and of their preferences for a variety of water quality improvements likely to follow from pollution reduction programs. The goal of the project is to obtain valuation estimates that can be used to evaluate alternative policies and approaches to improving water in the Chesapeake Bay.

  16. 33 CFR 80.510 - Chesapeake Bay Entrance, VA.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Chesapeake Bay Entrance, VA. 80.510 Section 80.510 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Fifth District § 80.510 Chesapeake Bay Entrance, VA. A...

  17. The Chesapeake Bay through Ebony Eyes. Curriculum Guide.

    ERIC Educational Resources Information Center

    Quillin, Holli S.

    This curriculum guide contains eight lessons which complement "The Chesapeake Bay through Ebony Eyes," a book that recounts the contributions blacks have made to Maryland's Chesapeake Bay's maritime and seafood industries. The guide is for use as supplemental material or as cultural enrichment. Lesson plans in the guide are: (1)…

  18. 33 CFR 80.510 - Chesapeake Bay Entrance, VA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Chesapeake Bay Entrance, VA. 80.510 Section 80.510 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Fifth District § 80.510 Chesapeake Bay Entrance, VA. A...

  19. 33 CFR 80.510 - Chesapeake Bay Entrance, VA.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Chesapeake Bay Entrance, VA. 80.510 Section 80.510 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Fifth District § 80.510 Chesapeake Bay Entrance, VA. A...

  20. 33 CFR 80.510 - Chesapeake Bay Entrance, VA.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Chesapeake Bay Entrance, VA. 80.510 Section 80.510 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Fifth District § 80.510 Chesapeake Bay Entrance, VA. A...

  1. 33 CFR 80.510 - Chesapeake Bay Entrance, VA.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Chesapeake Bay Entrance, VA. 80.510 Section 80.510 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Fifth District § 80.510 Chesapeake Bay Entrance, VA. A...

  2. MISR Views Delaware Bay, Chesapeake Bay, and the Appalachian Mountains

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Multi-angle Imaging SpectroRadiometer (MISR) images of Delaware Bay, Chesapeake Bay, and the Appalachian Mountains acquired on March 24, 2000 during Terra orbit 1417. The large image on the right was taken by the MISR camera viewing straight down (nadir). The series of smaller images, from top to bottom, respectively, were taken by cameras viewing 70.5 degrees forward, 45.6 degrees forward, 45.6 degrees aftward, and 70.5 degrees aftward of nadir. These images cover the environs of Newark, Philadelphia, Baltimore, Washington, and Richmond. Differences in brightness, color, and contrast as a function of view angle are visible over both land and water. Scientists are using MISR data to monitor changes in clouds, Earth's surface, and pollution particles in the air, and to assess their impact on climate. North is toward the top.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

    For more information: http://www-misr.jpl.nasa.gov

  3. Sediment calibration strategies of Phase 5 Chesapeake Bay watershed model

    USGS Publications Warehouse

    Wu, J.; Shenk, G.W.; Raffensperger, J.; Moyer, D.; Linker, L.C.; ,

    2005-01-01

    Sediment is a primary constituent of concern for Chesapeake Bay due to its effect on water clarity. Accurate representation of sediment processes and behavior in Chesapeake Bay watershed model is critical for developing sound load reduction strategies. Sediment calibration remains one of the most difficult components of watershed-scale assessment. This is especially true for Chesapeake Bay watershed model given the size of the watershed being modeled and complexity involved in land and stream simulation processes. To obtain the best calibration, the Chesapeake Bay program has developed four different strategies for sediment calibration of Phase 5 watershed model, including 1) comparing observed and simulated sediment rating curves for different parts of the hydrograph; 2) analyzing change of bed depth over time; 3) relating deposition/scour to total annual sediment loads; and 4) calculating "goodness-of-fit' statistics. These strategies allow a more accurate sediment calibration, and also provide some insightful information on sediment processes and behavior in Chesapeake Bay watershed.

  4. Petrography, mineralogy, and geochemistry of deep gravelly sands in the Eyreville B core, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Bartosova, Katerina; Gier, Susanne; Horton, J. Wright; Koeberl, Christian; Mader, Dieter; Dypvik, Henning

    2010-01-01

    The ICDP–USGS Eyreville drill cores in the Chesapeake Bay impact structure reached a total depth of 1766 m and comprise (from the bottom upwards) basement-derived schists and granites/pegmatites, impact breccias, mostly poorly lithified gravelly sand and crystalline blocks, a granitic slab, sedimentary breccias, and postimpact sediments. The gravelly sand and crystalline block section forms an approximately 26 m thick interval that includes an amphibolite block and boulders of cataclastic gneiss and suevite. Three gravelly sands (basal, middle, and upper) are distinguished within this interval. The gravelly sands are poorly sorted, clast supported, and generally massive, but crude size-sorting and subtle, discontinuous layers occur locally. Quartz and K-feldspar are the main sand-size minerals and smectite and kaolinite are the principal clay minerals. Other mineral grains occur only in accessory amounts and lithic clasts are sparse (only a few vol%). The gravelly sands are silica rich (~80 wt% SiO2). Trends with depth include a slight decrease in SiO2 and slight increase in Fe2O3. The basal gravelly sand (below the cataclasite boulder) has a lower SiO2 content, less K-feldspar, and more mica than the higher sands, and it contains more lithic clasts and melt particles that are probably reworked from the underlying suevite. The middle gravelly sand (below the amphibolite block) is finer-grained, contains more abundant clay minerals, and displays more variable chemical compositions than upper gravelly sand (above the block). Our mineralogical and geochemical results suggest that the gravelly sands are avalanche deposits derived probably from the nonmarine Potomac Formation in the lower part of the target sediment layer, in contrast to polymict diamictons higher in the core that have been interpreted as ocean-resurge debris flows, which is in agreement with previous interpretations. The mineralogy and geochemistry of the gravelly sands are typical for a passive

  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

    USGS Publications Warehouse

    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. Seasonal oxygen depletion in Chesapeake Bay

    SciTech Connect

    Taft, J.L.; Hartwig, E.O.; Loftus, R.

    1980-12-01

    The spring freshet increases density stratification in Chesapeake Bay and minimizes oxygen transfer from the surface to the deep layer so that waters below 10 m depth experience oxygen depletion which may lead to anoxia during June to September. Respiration in the water of the deep layer is the major factor contributing to oxygen depletion. Benthic respiration seems secondary. Organic matter from the previous year which has settled into the deep layer during winter provides most of the oxygen demand but some new production in the surface layer may sink and thus supplement the organic matter accumulated in the deep layer.

  7. U.S. Geological Survey Science—Improving the value of the Chesapeake Bay watershed

    USGS Publications Warehouse

    Phillips, Scott W.; Hyer, Kenneth; Goldbaum, Elizabeth

    2017-05-05

    IntroductionCongress directed the Federal Government to work with States to restore the Nation’s largest estuary.Chesapeake Bay restoration provides important economic and ecological benefits:18 million people live and work in the Bay watershed and enjoy its benefits.3,600 types of fish, wildlife, and plants underpin the economic value of the Bay ecosystem.Poor water quality and habitat loss threaten restoration and negatively impact the economy.10 Goals to meet by 2025 through the Chesapeake Bay Program, a voluntary partnership.

  8. The Chesapeake Bay crater: geology and geophysics of a Late Eocene submarine impact structure

    USGS Publications Warehouse

    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).

  9. The effects of the Chesapeake Bay impact crater on the geologic framework and the correlation of hydrogeologic units of southeastern Virginia, south of the James River

    USGS Publications Warehouse

    Powars, David S.

    2000-01-01

    About 35 million years ago, a large comet or meteor slammed into the shallow shelf on the western margin of the Atlantic Ocean, creating the Chesapeake Bay impact crater. This report, the second in a series, refines the geologic framework of southeastern Virginia, south of the James River in and near the impact crater, and presents evidence for the existence of a pre-impact James River structural zone. The report includes detailed correlations of core lithologies with borehole geophysical logs; the correlations provide the foundation for the compilation of stratigraphic cross sections. These cross sections are tied into the geologic framework of the lower York-James Peninsula as presented in the first report in the series, Professional Paper 1612

  10. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...-west line through Chesapeake Beach Light 2 at the entrance channel to Fishing Creek; on the south by an...

  11. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Code of Federal Regulations, 2010 CFR

    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...-west line through Chesapeake Beach Light 2 at the entrance channel to Fishing Creek; on the south by an...

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

    USGS Publications Warehouse

    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.

  13. 33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... approaches to Chesapeake Bay: Southern approach. (a) A separation line connects the following geographical... established in paragraph (g) of this section when bound for Chesapeake Bay from sea or to sea from Chesapeake... (g) of this section— (1) Announce its intention on VHF-FM Channel 16 as it approaches Chesapeake Bay...

  14. 33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... approaches to Chesapeake Bay: Southern approach. (a) A separation line connects the following geographical... established in paragraph (g) of this section when bound for Chesapeake Bay from sea or to sea from Chesapeake... (g) of this section— (1) Announce its intention on VHF-FM Channel 16 as it approaches Chesapeake Bay...

  15. Establishing the link between the Chesapeake Bay impact structure and the North American tektite strewn field: The Sr-Nd isotopic evidence

    NASA Astrophysics Data System (ADS)

    Deutsch, Alexander; Koeberl, Christian

    2006-05-01

    The Chesapeake Bay impact structure, which is about 35 Ma old, has previously been proposed as the possible source crater of the North American tektites (NAT). Here we report major and trace element data as well as the first Sr-Nd isotope data for drill core and outcrop samples of target lithologies, crater fill breccias, and post-impact sediments of the Chesapeake Bay impact structure. The unconsolidated sediments, Cretaceous to middle Eocene in age, have ɛSrt = 35.7 Ma of +54 to +272, and ɛNdt = 35.7 Ma ranging from -6.5 to -10.8; one sample from the granitic basement with a TNdCHUR model age of 1.36 Ga yielded an ɛSrt = 35.7 Ma of +188 and an ɛNdt = 35.7 Ma of -5.7. The Exmore breccia (crater fill) can be explained as a mix of the measured target sediments and the granite, plus an as-yet undetermined component. The post-impact sediments of the Chickahominy formation have slightly higher TNdCHUR model ages of about 1.55 Ga, indicating a contribution of some older materials. Newly analyzed bediasites have the following isotope parameters: +104 to +119 (ɛSrt = 35.7 Ma), -5.7 (ɛNdt = 35.7 Ma), 0.47 Ga (TSrUR), and 1.15 Ga (TNdCHUR), which is in excellent agreement with previously published data for samples of the NAT strewn field. Target rocks with highly radiogenic Sr isotopic composition, as required for explaining the isotopic characteristics of Deep Sea Drilling Project (DSDP) site 612 tektites, were not among the analyzed sample suite. Based on the new isotope data, we exclude any relation between the NA tektites and the Popigai impact crater, although they have identical ages within 2σ errors. The Chesapeake Bay structure, however, is now clearly constrained as the source crater for the North American tektites, although the present data set obviously does not include all target lithologies that have contributed to the composition of the tektites.

  16. Distribution of viruses in the Chesapeake Bay.

    PubMed Central

    Wommack, K E; Hill, R T; Kessel, M; Russek-Cohen, E; Colwell, R R

    1992-01-01

    High virus counts were found in water samples collected from the Chesapeake Bay. Viruses were enumerated by ultracentrifugation of water samples onto grids which were visualized by transmission electron microscopy. Virus counts in September 1990, April 1991, June 1991, August 1991, and October 1991 ranged between 2.6 x 10(6) and 1.4 x 10(8) viruses ml-1 with a mean of 2.5 x 10(7) viruses ml-1. Virus counts were usually at least three times higher than direct bacterial counts in corresponding samples. Virus counts in August and October were significantly higher than at the other sampling times, whereas bacterial counts were significantly lower at that time, yielding mean virus-to-bacterium ratios of 12.6 and 25.6, respectively. From analysis of morphology of the virus particles, it is concluded that a large proportion of the viruses are bacteriophages. The high virus counts obtained in this study suggest that viruses may be an important factor affecting bacterial populations in the Chesapeake Bay, with implications for gene transfer in natural aquatic bacterial populations and release of genetically engineered microorganisms to estuarine and coastal environments. PMID:1444409

  17. Ecological Functions of Shallow, Unvegetated Esturaine Habitats and Potential Dredging Impacts (With Emphasis on Chesapeake Bay)

    DTIC Science & Technology

    2005-12-01

    the bottom when anchoring their vessels. Such direct impacts are already of concern for SAV’s ( Asplund and Cook 1997, Blackhurst and Cole 2000...and Wildlife Service, Washington, DC. FWS/OBS-80/07. Asplund , T. R., and Cook, C. M. (1997). “Effects of motor boats on submerged aquatic

  18. Resource protection for waterbirds in Chesapeake Bay

    USGS Publications Warehouse

    Erwin, R.M.; Haramis, G.M.; Krementz, D.G.; Funderburk, S.L.

    1993-01-01

    Many living resources in the Chesapeake Bay estuary have deteriorated over the past 50 years. As a result, many governmental committees, task forces, and management plans have been established. Most of the recommendations for implementing a bay cleanup focus on reducing sediments and nutrient flow into the watershed. We emphasize that habitat requirements other than water quality are necessary for the recovery of much of the bay's avian wildlife, and we use a waterbird example as illustration. Some of these needs are: (1) protection of fast-eroding islands, or creation of new ones by dredge deposition to improve nesting habitat for American black ducks(Anas rubripes), great blue herons(Ardea herodias), and other associated wading birds; (2) conservation of remaining brackish marshes, especially near riparian areas, for feeding black ducks, wading birds, and wood ducks(Aix sponsa); (3) establishment of sanctuaries in open-water, littoral zones to protect feeding and/or roosting areas for diving ducks such as canvasbacks(Aythya valisineria) and redheads(Aythya americana), and for bald eagles(Haliaeetus leucocephalus); and (4) limitation of disturbance by boaters around nesting islands and open-water feeding areas. Land (or water) protection measures for waterbirds need to include units at several different spatial scales, ranging from ?points? (e.g., a colony site) to large-area resources (e.g., a marsh or tributary for feeding). Planning to conserve large areas of both land and water can be achieved following a biosphere reserve model. Existing interagency committees in the Chesapeake Bay Program could be more effective in developing such a model for wildlife and fisheries resources.

  19. Resource protection for waterbirds in Chesapeake bay

    NASA Astrophysics Data System (ADS)

    Erwin, R. Michael; Haramis, G. Michael; Krementz, David G.; Funderburk, Steven L.

    1993-09-01

    Many living resources in the Chesapeake Bay estuary have deteriorated over the past 50 years. As a result, many governmental committees, task forces, and management plans have been established. Most of the recommendations for implementing a bay cleanup focus on reducing sediments and nutrient flow into the watershed. We emphasize that habitat requirements other than water quality are necessary for the recovery of much of the bay's avian wildlife, and we use a waterbird example as illustration. Some of these needs are: (1) protection of fast-eroding islands, or creation of new ones by dredge deposition to improve nesting habitat for American black ducks (Anas rubripes), great blue herons (Ardea herodias), and other associated wading birds; (2) conservation of remaining brackish marshes, especially near riparian areas, for feeding black ducks, wading birds, and wood ducks (Aix sponsa); (3) establishment of sanctuaries in open-water, littoral zones to protect feeding and/or roosting areas for diving ducks such as canvasbacks (Aythya valisineria) and redheads (Aythya americana), and for bald eagles (Haliaeetus leucocephalus); and (4) limitation of disturbance by boaters around nesting islands and open-water feeding areas. Land (or water) protection measures for waterbirds need to include units at several different spatial scales, ranging from “points” (e.g., a colony site) to large-area resources (e.g., a marsh or tributary for feeding). Planning to conserve large areas of both land and water can be achieved following a biosphere reserve model. Existing interagency committees in the Chesapeake Bay Program could be more effective in developing such a model for wildlife and fisheries resources.

  20. A review of atmospheric nitrogen loading estimates to Chesapeake Bay

    SciTech Connect

    Valigura, R.A.; Baker, J.E.; McConnell, L.L.

    1994-12-31

    The importance of atmospheric nitrogen deposition to the Chesapeake Bay and its watershed has been reflected in the number of articles recently published on the peer reviewed literature. Based upon a recent literature synthesis, an evaluation of the magnitude and relative importance of atmospheric nitrogen deposition to the Chesapeake Bay and its watershed will be presented. Key steps required to reduce the uncertainty in atmospheric deposition loading estimates will be outlined. Estimates of nitrogen loadings to Chesapeake Bay will be compared to estimates published for other waterbodies.

  1. Heat flow and brine generation following the Chesapeake Bay bolide impact

    USGS Publications Warehouse

    Sanford, W.

    2003-01-01

    Calculations indicate that the impact of an asteroid or comet on the Atlantic Coastal Plain 35 million years ago created subsequent hydrothermal activity and conditions suitable for phase separation and the creation of the brine observed in the groundwater at the site today. A calculation of groundwater velocity using Darcy's law suggests flow rates are insufficient to have moved the water out of the crater within 35 million years. A similar calculation using Pick's law demonstrates that solutes cannot have escaped by molecular diffusion since the impact. Simulations from other investigators using shock-physics codes indicate that the crust would have been vaporized or melted down to at least 2 km at the time of impact. Based on these calculations, a simulation of heat conduction was made assuming a 1000 ??C initial crustal temperature. The hot crust acted as a heat source, with temperatures peaking in the overlying sediment about 10,000 years later. The pressure and temperature conditions within the sediment during that time would have been favorable for phase separation and generation of a residual brine, which may be found today in the inner crater. ?? 2003 Elsevier Science B.V. All rights reserved.

  2. Understanding the estuary: Advances in Chesapeake Bay research

    SciTech Connect

    Lynch, M.P.; Krome, E.C.

    1988-08-01

    The conference proceedings provides a context for assessing the relevance of scientific findings to the long-term efforts to protect and restore the Chesapeake watershed. The conference was primarily oriented towards scientists engaged in research on fundamental estuarine processes in Chesapeake Bay and secondarily oriented to managers with scientific and technical backgrounds.

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

    USGS Publications Warehouse

    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. The impact of urban expansion and agricultural legacies on trace metal accumulation in fluvial and lacustrine sediments of the lower Chesapeake Bay basin, USA.

    PubMed

    Coxon, T M; Odhiambo, B K; Giancarlo, L C

    2016-10-15

    The progressively declining ecological condition of the Chesapeake Bay is attributed to the influx of contaminants associated with sediment loads supplied by its largest tributaries. The continued urban expansion in the suburbs of Virginia cities, modern agricultural activities in the Shenandoah Valley, the anthropogenic and climate driven changes in fluvial system hydrodynamics and their potential associated impacts on trace metals enrichment in the bay's tributaries necessitate constant environmental monitoring of these important water bodies. Eight (210)Pb and (137)Cs dated sediment cores and seventy two sediment grab samples were used to analyze the spatial and temporal distributions of Al, Ca, Mg, Cr, Cd, As, Se, Pb, Cu, Zn, Mn, and Fe in the waterways of the Virginia portion of the Chesapeake Bay basin. The sediment cores for trace metal historical fluctuation analysis were obtained in lower fluvial-estuarine environments and reservoirs in the upper reaches of the basin. The trace metal profiles revealed high basal enrichment factors (EF) of between 0.05 and 40.24, which are interpreted to represent early nineteenth century agricultural activity and primary resource extraction. Surficial enrichment factors on both cores and surface grab samples ranged from 0.01 (Cu) to 1421 (Cd), with Pb, Cu, Zn, and Cd enrichments a plausible consequence of modern urban expansion and industrial development along major transportation corridors. Contemporary surficial enrichments of As, Se, and Cr also ranged between 0 and 137, with the higher values likely influenced by lithological and atmospheric sources. Pearson correlation analyses suggest mining and agricultural legacies, coupled with aerosol deposition, are responsible for high metal concentrations in western lakes and headwater reaches of fluvial systems, while metal accumulation in estuarine reaches of the major rivers can be attributed to urban effluence and the remobilization of legacy sediments. Copyright © 2016

  5. INTEGRATED ASSESSMENTS OF THE ENVIRONMENTAL CONDITION OF THE CHESAPEAKE BAY

    EPA Science Inventory

    The Chesapeake Bay, the Nation's largest estuary, has experienced environmental degradation due to nutrient enrichment, contamination, loss of habitat, and over-harvesting of living resources. Resource managers need information on the extent of degradation to formulate restoratio...

  6. Problem-Solving Environmental Science on the Chesapeake Bay.

    ERIC Educational Resources Information Center

    Goodwin, Dean; Adkins, Jeannette C.

    1997-01-01

    Presents a continuing study on the Chesapeake Bay as an example of a problem-based approach to environmental education using real life problems. Argues that the approach gives students responsibility for their own learning. (DDR)

  7. PRIMARY PRODUCTION ESTIMATES IN CHESAPEAKE BAY USING SEAWIFS

    EPA Science Inventory

    The temporal and spatial variability in primary production along the main stem of Chesapeake Bay was examined from 1997 through 2000. Primary production estimates were determined from the Vertically Generalized Production Model (VGPM) (Behrenfeld and Falkowski, 1997) using chloro...

  8. Petrographic observations on the Exmore breccia, ICDP-USGS drilling at Eyreville, Chesapeake Bay impact structure, USA

    USGS Publications Warehouse

    Reimold, W.U.; Bartosova, K.; Schmitt, R.T.; Hansen, B.; Crasselt, C.; Koeberl, C.; Wittmann, A.; Powars, D.S.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville A and B drill cores sampled crater fill in the region of the crater moat, ??9 km to the NE of the center of the Chesapeake Bay impact structure, Virginia, USA. They provide a 953 m section (444-1397 m depth) of sedimentary clast breccia and intercalated sedimentary and crystalline megablocks knownas Exmore beds, deposited on top of the impactite sequence between 1397 and 1551 m depth. We petrographically investigated the sandy-clayey groundmass-dominated breccia, which resembles a diamictite ("Exmore breccia"), and which, in its lower parts, carries sedimentary and crystalline blocks. The entire breccia interval is characterizedby the presence of glauconite and bioclastic carbonate, which distinguishes the Exmore breccia from other sandy facies above and below in the stratigraphy. The sediment-clast breccia exhibits strong heterogeneity from sample to sample with respect to groundmass nature, e.g., clay versus sand content, as well as clast content, in general, and shocked clast content, in particular. There is a consistently signifi cantly larger macroscopic sedimentary to crystalline clast content. On the microscopic scale, the intersample sediment to crystalline clast ratios are quite variable. A very small component of shocked material, in the form of shock-deformed quartz, and to an even lesser degree feldspar, and somewhat more abundant but still relatively scarce shardshaped,altered melt particles, is present throughout the section. However, between ??458 and 469 m, and between 514 and 527 m depths, the abundance of such melt particlesis notably enhanced. These sections are also chemically distinct and relatively more mafic than the other parts of the Exmore breccia. It appears that from the time of deposition of the 527 m material, calming of the ocean occurred over the crater area as a result of abatement of resurge activity, so that ejecta from the

  9. Silicate glasses and sulfide melts in the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure, Virginia, USA

    USGS Publications Warehouse

    Belkin, H.E.; Horton, J.W.

    2009-01-01

    Optical and electron-beam petrography of melt-rich suevite and melt-rock clasts from selected samples from the Eyreville B core, Chesapeake Bay impact structure, reveal a variety of silicate glasses and coexisting sulfur-rich melts, now quenched to various sulfi de minerals (??iron). The glasses show a wide variety of textures, fl ow banding, compositions, devitrifi cation, and hydration states. Electron-microprobe analyses yield a compositional range of glasses from high SiO2 (>90 wt%) through a range of lower SiO2 (55-75 wt%) with no relationship to depth of sample. Some samples show spherical globules of different composition with sharp menisci, suggesting immiscibility at the time of quenching. Isotropic globules of higher interfacial tension glass (64 wt% SiO2) are in sharp contact with lower-surface-tension, high-silica glass (95 wt% SiO2). Immiscible glass-pair composition relationships show that the immiscibility is not stable and probably represents incomplete mixing. Devitrifi cation varies and some low-silica, high-iron glasses appear to have formed Fe-rich smectite; other glass compositions have formed rapid quench textures of corundum, orthopyroxene, clinopyroxene, magnetite, K-feldspar, plagioclase, chrome-spinel, and hercynite. Hydration (H2O by difference) varies from ~10 wt% to essentially anhydrous; high-SiO2 glasses tend to contain less H2O. Petrographic relationships show decomposition of pyrite and melting of pyrrhotite through the transformation series; pyrite? pyrrhotite? troilite??? iron. Spheres (~1 to ~50 ??m) of quenched immiscible sulfi de melt in silicate glass show a range of compositions and include phases such as pentlandite, chalcopyrite, Ni-As, monosulfi de solid solution, troilite, and rare Ni-Fe. Other sulfi de spheres contain small blebs of pure iron and exhibit a continuum with increasing iron content to spheres that consist of pure iron with small, remnant blebs of Fe-sulfi de. The Ni-rich sulfi de phases can be explained by

  10. 46 CFR 7.50 - Chesapeake Bay and tributaries.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Atlantic Coast § 7.50 Chesapeake Bay and tributaries. A line drawn from Cape Charles Light to latitude 36... latitude 36°54.8′ N. longitude 75°55.6′ W. (Chesapeake Bay Entrance Lighted Bell Buoy “CBC”); thence to latitude 36°55.0′ N. longitude 75°58.0′ W. (Cape Henry Buoy “1”); thence to Cape Henry Light....

  11. 46 CFR 7.50 - Chesapeake Bay and tributaries.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Atlantic Coast § 7.50 Chesapeake Bay and tributaries. A line drawn from Cape Charles Light to latitude 36... latitude 36°54.8′ N. longitude 75°55.6′ W. (Chesapeake Bay Entrance Lighted Bell Buoy “CBC”); thence to latitude 36°55.0′ N. longitude 75°58.0′ W. (Cape Henry Buoy “1”); thence to Cape Henry Light....

  12. The impact of sea-level rise on organic matter decay rates in Chesapeake Bay brackish tidal marshes

    USGS Publications Warehouse

    Kirwanm, M.L.; Langley, J.A.; Guntenspergen, Gleen R.; Megonigal, J.P.

    2013-01-01

    The balance between organic matter production and decay determines how fast coastal wetlands accumulate soil organic matter. Despite the importance of soil organic matter accumulation rates in influencing marsh elevation and resistance to sea-level rise, relatively little is known about how decomposition rates will respond to sea-level rise. Here, we estimate the sensitivity of decomposition to flooding by measuring rates of decay in 87 bags filled with milled sedge peat, including soil organic matter, roots and rhizomes. Experiments were located in field-based mesocosms along 3 mesohaline tributaries of the Chesapeake Bay. Mesocosm elevations were manipulated to influence the duration of tidal inundation. Although we found no significant influence of inundation on decay rate when bags from all study sites were analyzed together, decay rates at two of the sites increased with greater flooding. These findings suggest that flooding may enhance organic matter decay rates even in water-logged soils, but that the overall influence of flooding is minor. Our experiments suggest that sea-level rise will not accelerate rates of peat accumulation by slowing the rate of soil organic matter decay. Consequently, marshes will require enhanced organic matter productivity or mineral sediment deposition to survive accelerating sea-level rise.

  13. Rainfall regulates the impact of elevated atmospheric CO2 on carbon balance in Chesapeake Bay wetland and Florida Scrub Oak.

    NASA Astrophysics Data System (ADS)

    Drake, B. G.; Rasse, D.

    2004-12-01

    Elevated atmospheric CO2 (Ca) is expected to stimulate ecosystem carbon assimilation and reduce stomatal conductance and transpiration in native ecosystems but the interaction between these effects and water and nutrient supply is highly uncertain. We report results of measurements of Net Ecosystem CO2 Exchange (NEE) from an 18 year study of the effects of elevated Ca on a Chesapeake Bay Maryland wetland and a seven year study in a scrub oak ecosystem Cape Canaveral, Florida exposed to ambient or elevated (normal ambient plus 350 ppm) Ca in open top chambers which were also used to measure NEE. Although acclimation of photosynthesis was commonly observed, elevated Ca often caused a stimulation of photosynthesis of 35-100 percent. Elevated Ca stimulated NEE was the same or greater than NEE in sites at normal ambient Ca but inter-annual variation in the effect was large. Stimulation of NEE by elevated Ca was linearly correlated with rainfall. These results suggest that the inter-annual variation in the effects of elevated Ca on ecosystem carbon balance were due to the availability of water and not to other factors such as nitrogen supply.

  14. Total plankton respiration in the Chesapeake Bay plume

    NASA Technical Reports Server (NTRS)

    Robertson, C. N.; Thomas, J. P.

    1981-01-01

    Total plankton respiration (TPR) was measured at 17 stations within the Chesapeake Bay plume off the Virginia coast during March, June, and October 1980. Elevated rates of TPR, as well as higher concentrations of chlorophyll a and phaeopigment a, were found to be associated with the Bay plume during each survey. The TPR rates within the Bay plume were close to those found associated with the Hudson River plume for comparable times of the year. The data examined indicate that the Chesapeake Bay plume stimulates biological activity and is a source of organic loading to the contiguous shelf ecosystem.

  15. Bay BC's: A Multidisciplinary Approach To Teaching about the Chesapeake Bay.

    ERIC Educational Resources Information Center

    Slattery, Britt Eckhardt

    The Chesapeake Bay is the largest estuary in North America, providing food and habitat for an abundance of fish and wildlife. This booklet provides lesson plans for lower elementary students introducing the Chesapeake, its inhabitants, and pollution problems, and suggesting ways that individuals can contribute to the Bay's restoration. Background…

  16. Lowering Barriers to Achieving Multiple Environmental Goals in the Chesapeake Bay

    EPA Pesticide Factsheets

    In recognition of past unsuccessful restoration strategies for the Chesapeake Bay, President Obama signed Executive Order (EO) 13508 “Strategy for Protecting and Restoring the Chesapeake Bay Watershed” in 2009.

  17. Gaseous exchange of polycyclic aromatic hydrocarbons across the air-water interface of lower Chesapeake Bay

    SciTech Connect

    Gustafson, K.E.; Dickhut, R.M.

    1995-12-31

    The gaseous exchange fluxes of polycyclic aromatic hydrocarbons (PAHs) across the air-water interface of lower Chesapeake Bay were determined using a modified two-film exchange model. Sampling covered the period January 1994 to June 1995 for five sites on lower Chesapeake Bay ranging from rural to urban and highly industrialized. Simultaneous air and water samples were collected and the atmospheric gas phase and water column dissolved phase analyzed via GC/MS for 17 PAHs. The direction and magnitude of flux for each PAH was calculated using Henry`s law constants, hydrological and meteorological parameters, Temperature was observed to be an important environmental factor in determining both the direction and magnitude of PAH gas exchange. Nonetheless, wind speed significantly impacts mass transfer coefficients, and therefore was found to control the magnitude of flux. Spatial and temporal variation of PAH gaseous exchange fluxes were examined. Fluxes were determined to be both into and out of Chesapeake Bay. The range of gas exchange fluxes ({minus}560 to 600{micro}g/M{sup 2}*Mo) is of the same order to 10X greater than atmospheric wet and dry depositional fluxes to lower Chesapeake Bay. The results of this study support the hypothesis that gas exchange is a major transport process affecting the net loadings of PAHs in lower Chesapeake Bay.

  18. Projected 2050 Model Simulations for the Chesapeake Bay ...

    EPA Pesticide Factsheets

    The Chesapeake Bay Program as has been tasked with assessing how changes in climate systems are expected to alter key variables and processes within the Watershed in concurrence with land use changes. EPA’s Office of Research and Development will be conducting historic and future, 2050, Weather Research and Forecast (WRF) metrological and Community Multiscale Air Quality (CMAQ) chemical transport model simulations to provide meteorological and nutrient deposition estimates for inclusion of the Chesapeake Bay Program’s assessment of how climate and land use change may impact water quality and ecosystem health. This presentation will present the timeline and research updates. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and transport, and support environmental diagnostics/forensics with input from multiple data sources. It also develops media- and receptor-specific models, process models, and decision support tools for use both within and outside of EPA.

  19. Water residence time in Chesapeake Bay for 1980-2012

    NASA Astrophysics Data System (ADS)

    Du, Jiabi; Shen, Jian

    2016-12-01

    Concerns have grown over the increase of nutrients and pollutants discharged into the estuaries and coastal seas. The retention and export of these materials inside a system depends on the residence time (RT). A long-term simulation of time-varying RT of the Chesapeake Bay was conducted over the period from 1980 to 2012. The 33-year simulation results show that the mean RT of the entire Chesapeake Bay system ranges from 110 to 264 days, with an average value of 180 days. The RT was larger in the bottom layers than in the surface layers due to the persistent stratification and estuarine circulation. A clear seasonal cycle of RT was found, with a much smaller RT in winter than in summer, indicating materials discharged in winter would be quickly transported out of the estuary due to the winter-spring high flow. Large interannual variability of the RT was highly correlated with the variability of river discharge (R2 = 0.92). The monthly variability of RT can be partially attributed to the variability of estuarine circulation. A strengthened estuarine circulation results in a larger bottom influx and thus reduces the RT. Wind exerts a significant impact on the RT. The upstream wind is more important in controlling the lateral pattern of RT in the mainstem.

  20. Projected 2050 Model Simulations for the Chesapeake Bay ...

    EPA Pesticide Factsheets

    The Chesapeake Bay Program as has been tasked with assessing how changes in climate systems are expected to alter key variables and processes within the Watershed in concurrence with land use changes. EPA’s Office of Research and Development will be conducting historic and future, 2050, Weather Research and Forecast (WRF) metrological and Community Multiscale Air Quality (CMAQ) chemical transport model simulations to provide meteorological and nutrient deposition estimates for inclusion of the Chesapeake Bay Program’s assessment of how climate and land use change may impact water quality and ecosystem health. This presentation will present the timeline and research updates. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and transport, and support environmental diagnostics/forensics with input from multiple data sources. It also develops media- and receptor-specific models, process models, and decision support tools for use both within and outside of EPA.

  1. Guidance for protecting submerged aquatic vegetation in Chesapeake Bay from physical disruption

    SciTech Connect

    1995-08-01

    The document provides guidance for Chesapeake Bay resource managers and others on how existing submerged aquatic vegetation (SAV) and tidal shallow water habitats with potential for supporting SAV in the Bay can be fully protected, given current human uses of and demands on the Bay. In preparing this guidance document, the Submerged Aquatic Vegetation (SAV) Workgroup of the Chesapeake Bay Program`s Living Resources Subcommittee reviewed, summarized, and compared current state and federal policies and guidelines for protection of or minimizing impacts on SAV. Next, the workgroup identified key management issues facing the protection of existing and future SAV resources. Finally, building on current state and federal guidelines and policies, the workgroup identified guidance to first avoid, then minimize, direct impacts to SAV in the Bay and its tidal tributaries.

  2. Expanded USGS science in the Chesapeake Bay restoration

    USGS Publications Warehouse

    Phillips, Scott

    2010-01-01

    In May 2009, the President issued Executive Order (EO) 13508 for Chesapeake Bay Protection and Restoration. For the first time since the creation of the Chesapeake Bay Program (CBP) in 1983, the full weight of the Federal Government will be used to address the challenges facing the Chesapeake Bay. The EO directs the U.S. Department of the Interior (DOI), represented by the National Park Service (NPS), the U.S. Fish and Wildlife Service (USFWS), and the U.S. Geological Survey (USGS), to expand its efforts and increase leadership to restore the Bay and its watershed. A Federal Leadership Committee (FLC) was established to ensure coordination of Federal activities and consult with states and stakeholders to align restoration efforts.

  3. Cross-media approach to saving the Chesapeake Bay

    SciTech Connect

    Appleton, E.L.

    1995-12-01

    A project EPA began in August will investigate the possibility of cross-media emissions trading as a new approach to reducing nitrogen loadings to the Chesapeake Bay. Working with the Environmental Defense Fund (EDF), the Agency hopes to device a NO{sub x} trading framework along the lines of existing sulfur dioxide trading plans to control acid rain. The Chesapeake Air Project will examine the feasibility of using emissions trading between and water sources, including trading credits between power plants and mobile sources, to reduce the atmospheric deposition of nitrogen to the bay. The progress of the Bay Program nutrient reduction goals is up for reevaluation in 1997, and Knopes and EDF economist Brian Morton have high hopes that the trading plan, which would place a cap on the mass of emissions and rate of deposition allowed by all sources, will become the atmospheric deposition portion of the Chesapeake Bay Program`s Nutrient Reduction Strategy. 6 refs.

  4. Pore-water chemistry from the ICDP-USGS coer hole in the Chesapeake Bay impact structure--Implications for paleohydrology, microbial habitat, and water resources

    USGS Publications Warehouse

    Sanford, Ward E.; Voytek, Mary A.; Powars, David S.; Jones, Blair F.; Cozzarelli, Isabelle M.; Eganhouse, Robert P.; Cockell, Charles S.

    2009-01-01

    We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the pore-water chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. Pore water was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the drill hole. The pore-water samples were analyzed for major cations and anions, stable isotopes of water and sulfate, dissolved and total carbon, and bioavailable iron. The results reveal a broad transition between fresh and saline water from 100 to 500 m depth in the post-impact sediment section, and an underlying syn-impact section that is almost entirely filled with brine. The presence of brine in the lowermost post-impact section and the trend in the dissolved chloride with depth suggest a transport process dominated by molecular diffusion and slow, compaction-driven, upward flow. Major ion results indicate residual effects of diagenesis from heating, and a pre-impact origin for the brine. High levels of dissolved organic carbon (6-95 mg/L) and the distribution of electron acceptors indicate an environment that may be favorable for microbial activity throughout the drilled section. The concentration and extent of the brine is much greater than had previously been observed, suggesting its occurrence may be common in the inner crater. However, groundwater flow conditions in the structure may reduce the salt-water-intrusion hazard associated with the brine.

  5. 33 CFR 165.507 - Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone; Chesapeake Bay... Guard District § 165.507 Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD. (a... security zone: All waters of the Chesapeake Bay, from the surface to the bottom, within 250 yards north of...

  6. 33 CFR 334.320 - Chesapeake Bay entrance; naval restricted area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Chesapeake Bay entrance; naval... THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.320 Chesapeake Bay entrance; naval restricted area. (a) The area. Beginning at a point on the south shore of Chesapeake Bay at...

  7. 33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic separation scheme in the approaches to Chesapeake Bay consists of three parts: a Precautionary Area, an... Approaches to Chesapeake Bay should use the appropriate inbound or outbound traffic lane. ...

  8. 33 CFR 165.507 - Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone; Chesapeake Bay... Guard District § 165.507 Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD. (a... security zone: All waters of the Chesapeake Bay, from the surface to the bottom, within 250 yards north of...

  9. 33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic separation scheme in the approaches to Chesapeake Bay consists of three parts: a Precautionary Area, an... Approaches to Chesapeake Bay should use the appropriate inbound or outbound traffic lane. ...

  10. 75 FR 26155 - Safety Zone; Shore Thing & Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ..., Chesapeake Bay, Norfolk, VA AGENCY: Coast Guard, DHS. ACTION: Notice of proposed rulemaking. SUMMARY: The Coast Guard proposes establishing a temporary safety zone on the Chesapeake Bay in the vicinity of Ocean... action is intended to restrict vessel traffic movement on the Chesapeake Bay to protect mariners from the...

  11. 33 CFR 334.320 - Chesapeake Bay entrance; naval restricted area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Chesapeake Bay entrance; naval... THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.320 Chesapeake Bay entrance; naval restricted area. (a) The area. Beginning at a point on the south shore of Chesapeake Bay at...

  12. 75 FR 34367 - Safety Zone; Shore Thing & Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-17

    ..., Chesapeake Bay, Norfolk, VA AGENCY: Coast Guard, DHS. ACTION: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the Chesapeake Bay in the vicinity of Ocean View Beach... intended to restrict vessel traffic movement on the Chesapeake Bay ] to protect mariners from the hazards...

  13. 33 CFR 167.203 - In the approaches to Chesapeake Bay: Southern approach.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... approaches to Chesapeake Bay: Southern approach. (a) An inbound traffic lane is established between... use the deep-water route established in paragraph (c) of this section when bound for Chesapeake Bay from sea or to sea from Chesapeake Bay: (1) Deep draft vessels (drafts greater than 13.5 meters/45 feet...

  14. 33 CFR 334.320 - Chesapeake Bay entrance; naval restricted area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Chesapeake Bay entrance; naval... THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.320 Chesapeake Bay entrance; naval restricted area. (a) The area. Beginning at a point on the south shore of Chesapeake Bay at...

  15. 33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic separation scheme in the approaches to Chesapeake Bay consists of three parts: a Precautionary Area, an... Approaches to Chesapeake Bay should use the appropriate inbound or outbound traffic lane. ...

  16. 33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic separation scheme in the approaches to Chesapeake Bay consists of three parts: a Precautionary Area, an... Approaches to Chesapeake Bay should use the appropriate inbound or outbound traffic lane. ...

  17. 33 CFR 165.507 - Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone; Chesapeake Bay... Guard District § 165.507 Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD. (a... security zone: All waters of the Chesapeake Bay, from the surface to the bottom, within 250 yards north of...

  18. 33 CFR 167.200 - In the approaches to Chesapeake Bay Traffic Separation Scheme: General.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... § 167.200 In the approaches to Chesapeake Bay Traffic Separation Scheme: General. (a) The traffic separation scheme in the approaches to Chesapeake Bay consists of three parts: a Precautionary Area, an... Approaches to Chesapeake Bay should use the appropriate inbound or outbound traffic lane. ...

  19. 33 CFR 165.507 - Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone; Chesapeake Bay... Guard District § 165.507 Security Zone; Chesapeake Bay, between Sandy Point and Kent Island, MD. (a... security zone: All waters of the Chesapeake Bay, from the surface to the bottom, within 250 yards north of...

  20. Analysis of the Energy Performance of the Chesapeake Bay Foundation's Philip Merrill Environmental Center

    SciTech Connect

    Griffith, B.; Deru M.; Torcellini, P.; Ellis, P.

    2005-04-01

    The Chesapeake Bay Foundation designed their new headquarters building to minimize its environmental impact on the already highly polluted Chesapeake Bay by incorporating numerous high-performance energy saving features into the building design. CBF then contacted NREL to perform a nonbiased energy evaluation of the building. Because their building attracted much attention in the sustainable design community, an unbiased evaluation was necessary to help designers replicate successes and identify and correct problem areas. This report focuses on NREL's monitoring and analysis of the overall energy performance of the building.

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

    USGS Publications Warehouse

    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

  2. Distribution and movement of shortnose sturgeon (Acipenser brevirostrum) in the Chesapeake Bay

    USGS Publications Warehouse

    Welsh, S.A.; Mangold, M.F.; Skjeveland, J.E.; Spells, A.J.

    2002-01-01

    During a reward program for Atlantic sturgeon (Acipenser oxyrinchus), 40 federally endangered shortnose sturgeon (Acipenser brevirostrum) were captured and reported by commercial fishers between January 1996 and January 2000 from the Chesapeake Bay. Since this is more than double the number of published records of shortnose sturgeon in the Chesapeake Bay between 1876 and 1995, little information has been available on distributions and movement. We used fishery dependent data collected during the reward program to determine the distribution of shortnose sturgeon in the Chesapeake Bay. Sonically-tagged shortnose sturgeon in the Chesapeake Bay and Delaware River were tracked to determine if individuals swim through the Chesapeake and Delaware Canal. Shortnose sturgeon were primarily distributed within the upper Chesapeake Bay. The movements of one individual, tagged within the Chesapeake Bay and later relocated in the canal and Delaware River, indicated that individuals traverse the Chesapeake and Delaware Canal.

  3. Chesapeake Bay: an unprecedented decline in submerged aquatic vegetation

    SciTech Connect

    Orth, R.J.; Moore, K.A.

    1983-10-07

    Data on the distribution and abundance of submerged aquatic vegetation in Chesapeake Bay indicate a significant reduction in all species in all sections of the bay during the last 15 to 20 years. This decline is unprecedented in the bay's recent history. The reduction in one major species, Zostera marina, may be greater than the decline that occurred during the pandemic demise of the 1930's. 19 references, 2 figures.

  4. NET ANTHROPOGENIC PHOSPHORUS INPUTS; SPATIAL AND TEMPORAL VARIABILITY IN THE CHESAPEAKE BAY REGION

    EPA Science Inventory

    Coastal watershed eutrophication has increasingly become a regional and global issue as larger proportions of the earth’s human population settle in coastal areas. Human activities on the land have severely impacted the water resources of the Chesapeake Bay, one of the world’s l...

  5. (U-Th)/He Zircon Dating of Chesapeake Bay Ejecta; Ocean Drilling Program Site 1073A

    NASA Astrophysics Data System (ADS)

    Biren, M. B.; van Soest, M. C.; Wartho, J.-A.; Hodges, K. V.; Glass, B. P.; Koeberl, C.; Hale, W.

    2014-09-01

    Results from our (U-Th)/He zircon dating of distal ejecta associated with the 40 km diameter Chesapeake Bay impact structure of Virginia, are in excellent agreement with previous K-Ar and Ar-Ar dating studies of the North American tektites.

  6. NET ANTHROPOGENIC PHOSPHORUS INPUTS; SPATIAL AND TEMPORAL VARIABILITY IN THE CHESAPEAKE BAY REGION

    EPA Science Inventory

    Coastal watershed eutrophication has increasingly become a regional and global issue as larger proportions of the earth’s human population settle in coastal areas. Human activities on the land have severely impacted the water resources of the Chesapeake Bay, one of the world’s l...

  7. Progress report: long-term benthic monitoring and assessment program for the Maryland portion of Chesapeake Bay (July 1986-October 1987). Volume 1. Text

    SciTech Connect

    Holland, A.F.; Shaughnessy, A.T.; Scott, L.C.; Dickens, V.A.; Ranasinghe, J.A.

    1988-05-01

    The long-term benthic monitoring and assessment study for the Maryland portion of Chesapeake Bay is an integral component of the interdisciplinary Chesapeake Bay monitoring and assessment program. The major long-term objectives of the program are to: (1) determine the effectiveness of Baywide pollution abatement programs; (2) measure the cumulative, long-term impacts of power plant operations on Bay benthic resources; and (3) assess the status and trends for Bay water quality and biological resources. Sampling of benthic communities, sediments, and water quality was conducted from July 1, 1984 through December 1987 at 70 stations in the Maryland portion of the Chesapeake Bay and its tributaries.

  8. Detection of erosion events using 10Be profiles: example of the impact of agriculture on soil erosion in the Chesapeake Bay area (U.S.A.)

    USGS Publications Warehouse

    Valette-Silver, J. N.; Brown, L.; Pavich, M.; Klein, J.; Middleton, R.

    1986-01-01

    10Be concentration, total carbon and grain-size were measured in cores collected in undisturbed estuarine sediments of three tributaries of the Chesapeake Bay. These cores were previously studied by Davis [1] and Brush [2,3] for pollen content, age and sedimentation rate. In this work, we compare the results obtained for these various analyses. In the cores, we observed two increases in 10Be concentration concomitant with two major changes in the pollen composition of the sediments. These two pollen changes each correspond to well-dated agricultural horizons reflecting different stages in the introduction of European farming techniques [2]. In the Chesapeake Bay area, the agricultural development, associated with forest clearing, appears to have triggered the erosion, transport, and sedimentation into the river mouths of large quantities of 10Be-rich soils. This phenomenon explains the observed rise in the sedimentation rate associated with increases in agricultural land-use. ?? 1986.

  9. Pre-impact tectonothermal evolution of the crystalline basement-derived rocks in the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure

    USGS Publications Warehouse

    Gibson, R.L.; Townsend, G.N.; Horton, J.W.; Reimold, W.U.

    2009-01-01

    Pre-impact crystalline rocks of the lowermost 215 m of the Eyreville B drill core from the Chesapeake Bay impact structure consist of a sequence of pelitic mica schists with subsidiary metagraywackes or felsic metavolcanic rocks, amphibolite, and calc-silicate rock that is intruded by muscovite (??biotite, garnet) granite and granite pegmatite. The schists are commonly graphitic and pyritic and locally contain plagioclase porphyroblasts, fi brolitic sillimanite, and garnet that indicate middle- to upper-amphibolite-facies peak metamorphic conditions estimated at ??0.4-0.5 GPa and 600-670 ??C. The schists display an intense, shallowly dipping, S1 composite shear foliation with local micrometer- to decimeter-scale recumbent folds and S-C' shear band structures that formed at high temperatures. Zones of chaotically oriented foliation, resembling breccias but showing no signs of retrogression, are developed locally and are interpreted as shear-disrupted fold hinges. Mineral textural relations in the mica schists indicate that the metamorphic peak was attained during D1. Fabric analysis indicates, however, that subhorizontal shear deformation continued during retrograde cooling, forming mylonite zones in which high-temperature shear fabrics (S-C and S-C') are overprinted by progressively lower- temperature fabrics. Cataclasites and carbonate-cemented breccias in more competent lithologies such as the calc-silicate unit and in the felsic gneiss found as boulders in the overlying impactite succession may refl ect a fi nal pulse of low-temperature cataclastic deformation during D1. These breccias and the shear and mylonitic foliations are cut by smaller, steeply inclined anastomosing fractures with chlorite and calcite infill (interpreted as D2). This D2 event was accompanied by extensive chlorite-sericitecalcite ?? epidote retrogression and appears to predate the impact event. Granite and granite pegmatite veins display local discordance to the S1 foliation, but elsewhere

  10. Pore-water chemistry from the ICDP-USGS core hole in the Chesapeake Bay impact structure-Implications for paleohydrology, microbial habitat, and water resources

    USGS Publications Warehouse

    Sanford, W.E.; Voytek, M.A.; Powars, D.S.; Jones, B.F.; Cozzarelli, I.M.; Cockell, C.S.; Eganhouse, R.P.

    2009-01-01

    We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the pore-water chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. Pore water was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the drill hole. The pore-water samples were analyzed for major cations and anions, stable isotopes of water and sulfate, dissolved and total carbon, and bioavailable iron. The results reveal a broad transition between freshwater and saline water from 100 to 500 m depth in the postimpact sediment section, and an underlying synimpact section that is almost entirely filled with brine. The presence of brine in the lowermost postimpact section and the trend in dissolved chloride with depth suggest a transport process dominated by molecular diffusion and slow, compaction-driven, upward flow. Major ion results indicate residual effects of diagenesis from heating, and a pre-impact origin for the brine. High levels of dissolved organic carbon (6-95 mg/L) and the distribution of electron acceptors indicate an environment that may be favorable for microbial activity throughout the drilled section. The concentration and extent of the brine is much greater than had previously been observed, suggesting that its occurrence may be common in the inner crater. However, groundwater-flow conditions in the structure may reduce the saltwater-intrusion hazard associated with the brine. ?? 2009 The Geological Society of America.

  11. Impact of Environment and Ontogeny on Relative Fecundity and Egg Quality of Female Oysters (Crassostrea virginica) from Four Sites in Northern Chesapeake Bay.

    PubMed

    Glandon, Hillary Lane; Michaelis, Adriane K; Politano, Vincent A; Alexander, Stephanie T; Vlahovich, Emily A; Reece, Kimberly S; Koopman, Heather N; Meritt, Donald W; Paynter, Kennedy T

    2016-12-01

    Resource allocation to reproduction is a primary physiological concern for individuals, and can vary with age, environment, or a combination of both factors. In this study we quantified the impact of environment and individual age on the reproductive output of female oysters Crassostrea virginica. We determined the relative fecundity, egg total lipid content, and overall and omega-3/omega-6 (ω3/ω6) fatty acid signatures (FAS) of eggs spawned by female oysters over a 2-year period (n = 32 and n = 64). Variation was quantified spatially and ontogenetically by sampling young and old oyster populations from two rivers in Chesapeake Bay, totaling four collection sites. During Year 1, when oysters underwent oogenesis in different locations, overall and ω3/ω6 egg FAS varied significantly by river, with no significant differences observed in the FAS of oysters by age in Year 1. In Year 2, when oysters from different sites underwent oogenesis in a single location, no significant differences in the overall egg FAS or ω3/ω6 egg FAS by river or age were observed. These findings suggest that oysters integrate environment into their reproductive output, but that time spent growing at a specific location (in this case, represented by oyster age) plays a relatively minor role in the biochemical composition of oyster eggs. These results have consequences for our understanding of how resources are allocated from the female oyster to eggs and, more generally, the impact of environment and ontogeny on reproductive physiology.

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

    PubMed Central

    Shaw, Kristi S.; Jacobs, John M.; Crump, Byron C.

    2013-01-01

    To determine if a storm event (i.e., high winds, large volumes of precipitation) could alter concentrations of Vibrio vulnificus and V. 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 (MPN) 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 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 4 × 105 MPN g-1, V. parahaemolyticus 1 × 105 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

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

    PubMed

    Shaw, Kristi S; Jacobs, John M; Crump, Byron C

    2014-01-01

    To determine if a storm event (i.e., high winds, large volumes of precipitation) could alter concentrations of Vibrio vulnificus and V. 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 (MPN) 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 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 4 × 10(5) MPN g(-1), V. parahaemolyticus 1 × 10(5) MPN g(-1)), and virulence-associated genes were detected in most oyster samples. This study provides a first estimate of storm-related Vibrio density

  14. Tin and Tin-Resistant Microorganisms in Chesapeake Bay

    PubMed Central

    Hallas, L. E.; Cooney, J. J.

    1981-01-01

    Sediment and water samples from nine stations in Chesapeake Bay were examined for tin content and for microbial populations resistant to inorganic tin (75 mg of Sn liter−1 as SnCl4·5H2O) or to the organotin compound dimethyltin chloride [15 mg of Sn liter−1 as (CH3)2SnCl2]. Tin concentrations in sediments were higher (3.0 to 7.9 mg kg−1) at sites impacted by human activity than at open water sites (0.8 to 0.9 mg kg−1), and they were very high (239.6 mg kg−1) in Baltimore Harbor, which is impacted by both shipping and heavy industry. Inorganic tin (75 mg Sn liter−1) in agar medium significantly decreased viable counts, but its toxicity was markedly reduced in liquid medium; it was not toxic in medium solidified with silica gel. Addition of SnCl4·5H2O to these media produced a tin precipitate which was not involved in the metal's toxicity. The data suggest that a soluble tin-agar complex which is toxic to cells is formed in agar medium. Thus, the toxicity of tin depends more on the chemical species than on the metal concentration in the medium. All sites in Chesapeake Bay contained organisms resistant to tin. The microbial flora was more sensitive to (CH3)2SnCl2 than to SnCl4·5H2O. The elevated level of tin-resistant microorganisms in some aeas not containing unusually high tin concentrations suggests that factors other than tin may participate in the selection for a tin-tolerant microbial flora. PMID:16345719

  15. Geologic columns for the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure: Impactites and crystalline rocks, 1766 to 1096 m depth

    USGS Publications Warehouse

    Horton, J. Wright; Gibson, R.L.; Reimold, W.U.; Wittmann, A.; Gohn, G.S.; Edwards, L.E.

    2009-01-01

    The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and crystalline-rock sections in the cores. The lowermost cored section (1766-1551 m depth) is a complex assemblage of mica schists that commonly contain graphite and fibrolitic sillimanite, intrusive granite pegmatites that grade into coarse granite, and local zones of mylonitic deformation. This basement-derived section is variably overprinted by brittle cataclastic fabrics and locally cut by dikes of polymict impact breccia, including several suevite dikes. An overlying succession of suevites and lithic impact breccias (1551-1397 m) includes a lower section dominated by polymict lithic impact breccia with blocks (up to 17 m) and boulders of cataclastic gneiss and an upper section (above 1474 m) of suevites and clast-rich impact melt rocks. The uppermost suevite is overlain by 26 m (1397-1371 m) of gravelly quartz sand that contains an amphibolite block and boulders of cataclasite and suevite. Above the sand, a 275-m-thick allochthonous granite slab (1371-1096 m) includes gneissic biotite granite, fine- and medium-to-coarse-grained biotite granites, and red altered granite near the base. The granite slab is overlain by more gravelly sand, and both are attributed to debris-avalanche and/or rockslide deposition that slightly preceded or accompanied seawater-resurge into the collapsing transient crater. ?? 2009 The Geological Society of America.

  16. Scrubbing the Bay: Nutrient Removal Using Small Algal Turf Scrubbers on Chesapeake Bay Tributaries

    USDA-ARS?s Scientific Manuscript database

    Restoration of the Chesapeake Bay poses significant challenges because of increasing population pressure, conversion of farmland to urban/suburban development, and the expense of infrastructure needed to achieve significant and sustained nutrient reductions from agricultural and urban sources. One ...

  17. Transitioning a Chesapeake Bay Ecological Prediction System to Operations

    NASA Astrophysics Data System (ADS)

    Brown, C.; Green, D. S.; Eco Forecasters

    2011-12-01

    Ecological prediction of the impacts of physical, chemical, biological, and human-induced change on ecosystems and their components, encompass a wide range of space and time scales, and subject matter. They vary from predicting the occurrence and/or transport of certain species, such harmful algal blooms, or biogeochemical constituents, such as dissolved oxygen concentrations, to large-scale ecosystem responses and higher trophic levels. The timescales of ecological prediction, including guidance and forecasts, range from nowcasts and short-term forecasts (days), to intraseasonal and interannual outlooks (weeks to months), to decadal and century projections in climate change scenarios. The spatial scales range from small coastal inlets to basin and global scale biogeochemical and ecological forecasts. The types of models that have been used include conceptual, empirical, mechanistic, and hybrid approaches. This presentation will identify the challenges and progress toward transitioning experimental model-based ecological prediction into operational guidance and forecasting. Recent efforts are targeting integration of regional ocean, hydrodynamic and hydrological models and leveraging weather and water service infrastructure to enable the prototyping of an operational ecological forecast capability for the Chesapeake Bay and its tidal tributaries. A path finder demonstration predicts the probability of encountering sea nettles (Chrysaora quinquecirrha), a stinging jellyfish. These jellyfish can negatively impact safety and economic activities in the bay and an impact-based forecast that predicts where and when this biotic nuisance occurs may help management effects. The issuance of bay-wide nowcasts and three-day forecasts of sea nettle probability are generated daily by forcing an empirical habitat model (that predicts the probability of sea nettles) with real-time and 3-day forecasts of sea-surface temperature (SST) and salinity (SSS). In the first demonstration

  18. Comparative study of the aerobic, heterotrophic bacterial flora of Chesapeake Bay and Tokyo Bay.

    PubMed Central

    Austin, B; Garges, S; Conrad, B; Harding, E E; Colwell, R R; Simidu, U; Taga, N

    1979-01-01

    A comparative study of the bacterial flora of the water of Chesapeake Bay and Tokyo Bay was undertaken to assess similarities and differences between the autochthonous flora of the two geographical sites and to test the hypothesis that, given similarities in environmental parameters, similar bacterial populations will be found, despite extreme geographic distance between locations. A total of 195 aerobic, heterotrophic bacterial strains isolated from Chesapeake Bay and Tokyo Bay water were examined for 115 biochemical, cultural, morphological, nutritional, and physiological characters. The data were analyzed by the methods of numerical taxonomy. From sorted similarity matrices, 77% of the isolates could be grouped into 30 phena and presumptively identified as Acinetobacter-Moraxella, Caulobacter, coryneforms, Pseudomonas, and Vibrio spp. Vibrio and Acinetobacter species were found to be common in the estuarine waters of Chesapeake Bay, whereas Acinetobacter-Moraxella and Caulobacter predominated in Tokyo Bay waters, at the sites sampled in the study. PMID:453838

  19. EUTROPHICATION OF CHESAPEAKE BAY: HISTORICAL TRENDS AND ECOLOGICAL INTERACTIONS

    EPA Science Inventory

    This review provides an integrated synthesis with timelines and evaluations of ecological responses to eutrophication in Chesapeake Bay, the largest estuary in the USA. Analyses of dated sediment cores reveal initial evidence of organic enrichment in approximately 200 y-old strat...

  20. Ecosystem Services and Environmental Markets in Chesapeake Bay Restoration

    EPA Science Inventory

    This report contains two separate analyses, both of which make use of an optimization framework previously developed to evaluate trade-offs in alternative restoration strategies to achieve the Chesapeake Bay Total Maximum Daily Load (TMDL). The first analysis expands on model app...

  1. EUTROPHICATION OF CHESAPEAKE BAY: HISTORICAL TRENDS AND ECOLOGICAL INTERACTIONS

    EPA Science Inventory

    This review provides an integrated synthesis with timelines and evaluations of ecological responses to eutrophication in Chesapeake Bay, the largest estuary in the USA. Analyses of dated sediment cores reveal initial evidence of organic enrichment in approximately 200 y-old strat...

  2. Ecosystem Services and Environmental Markets in Chesapeake Bay Restoration

    EPA Science Inventory

    This report contains two separate analyses, both of which make use of an optimization framework previously developed to evaluate trade-offs in alternative restoration strategies to achieve the Chesapeake Bay Total Maximum Daily Load (TMDL). The first analysis expands on model app...

  3. Projected 2050 Model Simulations for the Chesapeake Bay Program

    EPA Science Inventory

    The Chesapeake Bay Program as has been tasked with assessing how changes in climate systems are expected to alter key variables and processes within the Watershed in concurrence with land use changes. EPA’s Office of Research and Development will be conducting historic and...

  4. Chesapeake Bay database (version 1. 00) (for microcomputers). Data file

    SciTech Connect

    Not Available

    1988-11-11

    The Chesapeake Bay Database contains 337 records of discrete water quality observations, collected on 3 oceanographic cruises during the summers of 1985, 1986, and 1987. Each record contains 64 fields listing the hydrographic, chemical and biological data measured for each observation.

  5. Mycobacteria as Environmental Portent in Chesapeake Bay Fish Species

    PubMed Central

    Stine, Cynthia B.; Hungerford, Laura; Matsche, Mark; Driscoll, Cindy; Baya, Ana M.

    2007-01-01

    Infection with environmental mycobacteria is increasing among many Chesapeake Bay fish species. Prevalence in juvenile Atlantic menhaden differed between tributaries and ranged from 2% to 57%. Mycobacterial infection may be a syndromic sentinel of altered environmental conditions that threaten aquatic animal health. PMID:17479905

  6. Chesapeake Bay Low Freshwater Inflow Study. Appendix F. Map Folio.

    DTIC Science & Technology

    1984-09-01

    storage, conservation, growth restriction, oyster bed restoration , and fisheries management. The final report recommends that a comprehensive water...AHANNROCK RIVER YORK ~ \\ RIVERJ JAMS RVE ~7. MAP 3 CHESAPEAKE BAY Prorocefltrum minimum , OIFLAGELLATIE -"S -, ASE AVERAGE WESTERN ECO SYSTEMS TECNOLOGY

  7. Numerical Modeling of Storm Surges in Chesapeake Bay

    DTIC Science & Technology

    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

  8. Projected 2050 Model Simulations for the Chesapeake Bay Program

    EPA Science Inventory

    The Chesapeake Bay Program as has been tasked with assessing how changes in climate systems are expected to alter key variables and processes within the Watershed in concurrence with land use changes. EPA’s Office of Research and Development will be conducting historic and...

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

    USGS Publications Warehouse

    Phillips, Scott

    2006-01-01

    Since the mid-1980s, the USGS has been an active partner in the Chesapeake Bay Program (CBP), a multi-agency partnership led by the U.S. Environmental Protection Agency, working to achieve the restoration goals set forth in the Chesapeake 2000 agreement. This agreement established over 100 restoration commitments to be addressed by 2010. In 2005, which was the mid-point of the agreement, there was growing concern at all levels of government and by the public that ecological conditions in the Bay and its watershed had not significantly improved. The slow rate of improvement, coupled with the projected impact of human-population increase in the Bay watershed (fig. 1), implied that many desired ecological conditions will not be achieved by 2010. To address these challenges, the USGS wrote a new science plan for 2006-2011, and is synthesizing key findings to highlight the accomplishments from science activities for 2000-2005.

  10. Comparison of mid-bay and lateral station water quality data in the Chesapeake Bay mainstem: Chesapeake Bay program

    SciTech Connect

    Not Available

    1993-06-01

    Seasonal median water quality values were compared between stations in mid-Bay and lateral regions in seven east-west transects in the mainstem Chesapeake Bay. Comparisons were made over seven years, 1985-1991, for April-October surface layer medians of total phosphorus, total nitrogen, dissolved orthophosphate, dissolved inorganic nitrogen, total suspended solids, chlorophyll a, Secchi depth, and salinity. Comparisons were also made using spring (March-May) and summer (June-September) medians of surface and bottom salinity and dissolved oxygen. Comparisons were made using difference plots of raw data, scatter plots of annual seasonal medians, and the Wilcoxon matched-pairs test on annual seasonal medians. The graphical and statistical analyses confirmed each other. Correlation coefficients were also calculated between mid-Bay and lateral data series to estimate their degree of similarity over time, but could not be tested for statistical significance.

  11. The Chesapeake Bay Program: An opportunity to use an innovative monitoring technique

    NASA Technical Reports Server (NTRS)

    Mangiaracina, L.

    1978-01-01

    The goal of this program is to develop a management system that will protect and preserve the water quality of the Chesapeake Bay by effectively managing its uses and resources. To achieve this goal, three major objectives must be accomplished: (1) Determine what units of government have management responsibility for the environmental quality of the Chesapeake Bay, also to define how such management responsibility can best be structured so that communications and coordination can be improved between the respective units of government, research, educational institutions, concerned groups, and individuals. (2) Assess the principal factors having an adverse impact on the environmental quality of the Chesapeake Bay. Following this assessment and review of ongoing research, direct and coordinate research and abatement programs that will most effectively address these factors, and (3) analyze all environmental sampling data now being collected on the Chesapeake Bay and suggest and undertake methods for improving this data collection, and to establish a continuing capability for collecting storing, analyzing, and disseminating these data.

  12. Sediment Sources and Storage in the Chesapeake Bay Watershed

    NASA Astrophysics Data System (ADS)

    Gellis, A. C.; Landwehr, J. M.; Pavich, M.; Hupp, C. R.; Ritchie, J. C.

    2006-05-01

    Physically and chemically, sediment is a pollutant of concern in many waterbodies. In the Chesapeake Bay, sediment is having an adverse effect on the living resources and habitat of the Chesapeake Bay and its watershed. Identifying significant sources of watershed sediment is important in reducing sediment loads. In the Chesapeake Bay, several approaches were used to understand the sources, transport, and storage of watershed-derived sediment. From 1985 through 2001, the U.S. Geological Survey collected suspended sediment at 35 stations draining portions of the 103,000 km2 Chesapeake Bay. Of the 35 sites, 4 of the 6 highest sediment yields were in the Conestoga River Basin, Pennsylvania, which drains to the Susquehanna River. In the Susquehanna River Basin (43,600 km2), erosion rates were determined using atmospheric 10Be at 92 river outlets and confirmed that the highest rates of erosion were in the Conestoga River Basin. In three small watersheds draining to the Chesapeake Bay -- the Pocomoke River (157 km2), Little Conestoga Creek (68.1 km2), and Mattawoman Creek (92.8 km2) -- sediment sources were identified using a sediment-source identification approach. In this approach, the sources of fine-grained suspended sediment in transport can be established by comparing physical and chemical properties of the suspended sediment to potential sources. In this study, suspended sediment (< 0.062 mm) collected during storm runoff was compared to upland sediment sources (cropland, construction sites, and forest) and channel corridor sources (channel banks and bed) using radionuclides (210Pb, 137Cs), stable isotopes (13C, 15N), and total C, N, and P. Preliminary results are available for two of the three watersheds. In the Pocomoke River watershed, which drains the Coastal Plain physiographic province, ditch beds which were dug to drain cropland were a significant source of sediment. In the Little Conestoga Creek watershed, which drains the Piedmont physiographic province

  13. Megablocks and melt pockets in the Chesapeake Bay impact structure constrained by magnetic field measurements and properties of the Eyreville and Cape Charles cores

    USGS Publications Warehouse

    Shah, A.K.; Daniels, D.L.; Kontny, A.; Brozena, J.

    2009-01-01

    We use magnetic susceptibility and remanent magnetization measurements of the Eyreville and Cape Charles cores in combination with new and previously collected magnetic field data in order to constrain structural features within the inner basin of the Chesapeake Bay impact structure. The Eyreville core shows the first evidence of several-hundred-meter-thick basement-derived megablocks that have been transported possibly kilometers from their pre-impact location. The magnetic anomaly map of the structure exhibits numerous short-wavelength (<2 km) variations that indicate the presence of magnetic sources within the crater fill. With core magnetic properties and seismic reflection and refraction results as constraints, forward models of the magnetic field show that these sources may represent basementderived megablocks that are a few hundred meters thick or melt bodies that are a few dozen meters thick. Larger-scale magnetic field properties suggest that these bodies overlie deeper, pre-impact basement contacts between materials with different magnetic properties such as gneiss and schist or gneiss and granite. The distribution of the short-wavelength magnetic anomalies in combination with observations of small-scale (1-2 mGal) gravity field variations suggest that basement-derived megablocks are preferentially distributed on the eastern side of the inner crater, not far from the Eyreville core, at depths of around 1-2 km. A scenario where additional basement-derived blocks between 2 and 3 km depth are distributed throughout the inner basin-and are composed of more magnetic materials, such as granite and schist, toward the east over a large-scale magnetic anomaly high and less magnetic materials, such as gneiss, toward the west where the magnetic anomaly is lower-provides a good model fi t to the observed magnetic anomalies in a manner that is consistent with both gravity and seismic-refraction data. ?? 2009 The Geological Society of America.

  14. Geochemical methods for investigating past changes in Chesapeake Bay

    SciTech Connect

    Helz, G.R.; Adelson, J.M.

    1997-08-01

    The trace metals, Cu, Mo and Re have been measured in a number of sediment cores from the main stem of Chesapeake Bay and from the adjacent Patuxent estuary. The cores were dated with Pb-210, supplemented by C-14, pollen and Pu(239, 240). Mo and Re were measured by an isotope dilution method. Reconnaissance data on Os-187/Os-188 ratios were obtained by thermal ionization mass spectrometry. The data are used to investigate two questions: (1) what is the origin of the pervasive Cu contamination in the Chesapeake system, and (2) can profiles of these metals in cores provide information on the history of sulfidic conditions in the water column.

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

    USGS Publications Warehouse

    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.

  16. Chesapeake Bay plankton and fish abundance enhanced by Hurricane Isabel

    NASA Astrophysics Data System (ADS)

    Roman, M. R.; Boicourt, W. C.; Kimmel, D. G.; Miller, W. D.; Adolf, J. E.; Bichy, J.; Harding, L. W., Jr.; Houde, E. D.; Jung, S.; Zhang, X.

    Hurricane Isabel made landfall east of Cape Lookout, North Carolina, as a Category 2 (Safford-Simpson scale) hurricane on 18 September 2003. The storm's center tracked to the northwest, passing west of Chesapeake Bay (Figure 1) in the early morning of 19 September. Hurricane Isabel brought the highest storm surge and winds to the region since the Chesapeake-Potomac hurricane of 1933 and Hurricane Hazel in 1954 (http://www.erh. noaa.gov/er/akq/wx_events/hur/isabel_2003. htm). Storm surge was variable in the region, reaching a high of 2.7 m on the western side of the bay where the heaviest rainfall occurred. The highest sustained wind in the bay region reached 30.8 m s-1 at Gloucester Point,Virginia, with gusts to 40.7 m s-1.

  17. Agricultural costs of the Chesapeake Bay total maximum daily load.

    PubMed

    Kaufman, Zach; Abler, David; Shortle, James; Harper, Jayson; Hamlett, James; Feather, Peter

    2014-12-16

    This study estimates costs to agricultural producers of the Watershed Implementation Plans (WIPs) developed by states in the Chesapeake Bay Watershed to comply with the Chesapeake Bay total maximum daily load (TMDL) and potential cost savings that could be realized by a more efficient selection of agricultural Best Management Practices (BMPs) and spatial targeting of BMP implementation. The cost of implementing the WIPs between 2011 and 2025 is estimated to be about $3.6 billion (in 2010 dollars). The annual cost associated with full implementation of all WIP BMPs from 2025 onward is about $900 million. Significant cost savings can be realized through careful and efficient BMP selection and spatial targeting. If retiring up to 25% of current agricultural land is included as an option, Bay-wide cost savings of about 60% could be realized compared to the WIPs.

  18. River runoff effect on the suspended sediment property in the upper Chesapeake Bay using MODIS observations and ROMS simulations

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoming; Wang, Menghua

    2014-12-01

    Ocean color data derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the satellite Aqua from 2002 to 2012 and simulations from the Regional Ocean Modeling System (ROMS) are used to study the impact of the Susquehanna River discharge on the total suspended sediment (TSS) concentration in the upper Chesapeake Bay. Since the water in the upper Chesapeake Bay is highly turbid, the shortwave infrared (SWIR)-based atmospheric correction algorithm is used for deriving the normalized water-leaving radiance nLw(λ) spectra from MODIS-Aqua measurements. nLw(λ) spectra are further processed into the diffuse attenuation coefficient at the wavelength of 490 nm Kd(490) and TSS. MODIS-Aqua-derived monthly TSS concentration in the upper Chesapeake Bay and in situ Susquehanna River discharge data show similar patterns in seasonal variations. The TSS monthly temporal variation in the upper Chesapeake Bay is also found in phase with the monthly averaged river discharge data. Since the Susquehanna River discharge is mainly dominated by a few high discharge events due to winter-spring freshets or tropical storms in each year, the impact of these high discharge events on the upper Chesapeake Bay TSS is investigated. Both MODIS-measured daily TSS images and sediment data derived from ROMS simulations show that the Susquehanna River discharge is the dominant factor for the variations of TSS concentration in the upper Chesapeake Bay. Although the high river discharge event usually lasts for only a few days, its induced high TSS concentration in the upper Chesapeake Bay can sustain for ˜10-20 days. The elongated TSS rebounding stage is attributed to horizontal advection of slowly settling fine sediment from the Susquehanna River.

  19. Anaerobic ammonium oxidation (anammox) in Chesapeake Bay sediments.

    PubMed

    Rich, Jeremy J; Dale, Olivia R; Song, Bongkeun; Ward, Bess B

    2008-02-01

    Anaerobic ammonium oxidation (anammox) has recently been recognized as a pathway for the removal of fixed N from aquatic ecosystems. However, the quantitative significance of anammox in estuarine sediments is variable, and measurements have been limited to a few estuaries. We measured anammox and conventional denitrification activities in sediments along salinity gradients in the Chesapeake Bay and two of its sub-estuaries, the Choptank River and Patuxent River. Homogenized sediments were incubated with (14/15)N amendments of NH4+, NO3-, and NO2- to determine relative activities of anammox and denitrification. The percent of N2 production due to anammox (ra%) ranged from 0 to 22% in the Chesapeake system, with the highest ra% in the freshwater portion of the main stem of upper Chesapeake Bay, where water column NO3- concentrations are consistently high. Intermediate levels of relative anammox (10%) were detected at locations corresponding to tidal freshwater and mesohaline locations in the Choptank River, whereas anammox was not detected in the tidal freshwater location in the Patuxent River. Anammox activity was also not detected in the seaward end of Chesapeake Bay, where water column No3- concentrations are consistently low. The ra% did not correlate with NH4+ accumulation rate in anoxic sediment incubations, but ra% was related to water column NO3- concentrations and salinity. Anammox bacterial communities were also examined by amplifying DNA extracted from the upper Chesapeake Bay sediment with polymerase chain reaction (PCR) primers that are specific for 16S rRNA genes of anammox organisms. A total of 35 anammox-like sequences were detected, and phylogenetic analysis grouped the sequences in two distinct clusters belonging to the Candidatus "Scalindua" genus.

  20. Regional Earth System Prediction for the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Murtugudde, R. G.

    2009-12-01

    While the IPCC will continue to lead Earth System projections for global issues such as greenhouse gas levels and global temperature increase, high-resolution regional Earth System predictions will be crucial for producing effective decision-making tools for day-to-day, sustainable Earth System management and adaptive management of resources. Regional Earth System predictions and projections at the order of a few meters resolution from days to decades must be validated and provide uncertainties and skill scores to be usable. While the task is daunting, it would be criminally negligent of the global human not to embark on this task immediately. The observational needs for the integrated natural-human system for the regional Earth System are distinct from the global needs even though there are many overlaps. A prototype has been built for the Chesapeake Bay which issues routine seasonal outlooks and decadal projections for the air and watershed with linked products that include forecasts of pathogens, harmful algal blooms, sea nettles, fisheries, etc. A decision-making tool has been developed to allow the users to explore what-if scenarios and see the impact on the health of the Bay. Environmental indicators are being developed using mortality and morbidity data to generate predictive, pre-emptive, and personalized health forecasts. Skill of the forecasts and future plans will be discussed.

  1. Evaluation and Validation of Case 2 Algorithms in Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Harding, Lawrence W., Jr.; Magnuson, Adrea

    2004-01-01

    The high temporal and spatial resolution of satellite ocean color observations will prove invaluable for monitoring the health of coastal ecosystems where physical and biological variability demands sampling scales beyond that possible by ship. However, ocean color remote sensing of Case 2 waters is a challenging undertaking due to the optical complexity of the water. The focus of this SIMBIOS support has been to provide in situ optical measurements form Chesapeake Bay (CB) and adjacent mid-Atlantic bight (MAB) waters for use in algorithm development and validation efforts to improve the satellite retrieval of chlorophyll (chl a) in Case 2 waters. CB provides a valuable site for validation of data from ocean color sensors for a number of reasons. First, the physical dimensions of the Bay (greater than 6,500 square kilometers) make retrievals from satellites with a spatial resolution of approximately 1 kilometer (i.e., SeaWiFS) or less (i.e., MODIS) reasonable for most of the ecosystem. Second, CB is highly influenced by freshwater flow from major rivers, making it a classic Case 2 water body with significant concentrations of chlorophyll, particulates and chromophoric dissolved organic matter (CDOM) that highly impact the shape of reflectance spectra. Finally, past and ongoing research efforts provided an expensive data set of optical observations that support the goal of this project.

  2. Analysis of survey data on the chemistry of twenty-three streams in the Chesapeake Bay watershed: some implications of the impact of acid deposition. Final report

    SciTech Connect

    Janicki, A.; Cummins, R.

    1983-12-01

    A survey of the chemistry of 23 streams within the Chesapeake Bay watershed was conducted in the spring of 1983 to determine whether a potential for changes in water chemistry due to atmospheric inputs of acidic materials exists in any of these streams. Sampling was conducted weekly through the months of March and April. Three streams were identified as being likely affected by acid inputs due to relatively high H(+) and SO4(-2) concentrations and low alkalinities: Stockett's Run, Lyons Creek, and Muddy Creek. Elevated dissolved aluminum concentrations were observed in some Eastern Shore streams and are likely related to the predominance of clay soils in their watersheds.

  3. The role of power plant atmospheric emissions in the deposition of nitrogen to the Chesapeake Bay

    SciTech Connect

    Miller, P.E.

    1994-12-31

    The Maryland Power Plant Research Program (PPRP) has sponsored research on several aspects of atmospheric nitrogen emissions, source attribution, deposition estimation and impact assessment since the mid-eighties. The results of these studies will be presented and discussed in the context of power plant emissions control impact on nitrogen loadings to the Chesapeake Bay and watershed. Information needs with respect to power plant contribution and emission control policy will be identified and discussed from the perspective of PPRP.

  4. Synimpact-postimpact transition inside Chesapeake Bay crater

    USGS Publications Warehouse

    Poag, C.W.

    2002-01-01

    The transition from synimpact to postimpact sedimentation inside Chesapeake Bay impact crater began with accumulation of fallout debris, the final synimpact deposit. Evidence of a synimpact fallout layer at this site comes from the presence of unusual, millimeter-scale, pyrite microstructures at the top of the Exmore crater-fill breccia. The porous geometry of the pyrite microstructures indicates that they originally were part of a more extensive pyrite lattice that encompassed a layer of millimeter-scale glass microspherules-fallout melt particles produced by the bolide impact. Above this microspherule layer is the initial postimpact deposit, a laminated clay-silt-sand unit, 19 cm thick. This laminated unit is a dead zone, which contains abundant stratigraphically mixed and diagenetically altered or impact-altered microfossils (foraminifera, calcareous nannofossils, dinoflagellates, ostracodes), but no evidence of indigenous biota. By extrapolation of sediment-accumulation rates, I estimate that conditions unfavorable to microbiota persisted for as little as <1 k.y. to 10 k.y. after the bolide impact. Subsequently, an abrupt improvement of the late Eocene paleoenvironment allowed species-rich assemblages of foraminifera, ostracodes, dinoflagellates, radiolarians, and calcareous nannoplankton to quickly reoccupy the crater basin, as documented in the first sample of the Chickahominy Formation above the dead zone.

  5. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of Chesapeake Beach, Md.; firing range, Naval Research Laboratory. 334.170 Section 334.170 Navigation..., Naval Research Laboratory. (a) The danger zone—(1) Area A. A roughly rectangular area bounded on the... established fishing structure limit line; and on the west by the shore of Chesapeake Bay. (b) The regulations...

  6. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... of Chesapeake Beach, Md.; firing range, Naval Research Laboratory. 334.170 Section 334.170 Navigation..., Naval Research Laboratory. (a) The danger zone—(1) Area A. A roughly rectangular area bounded on the... established fishing structure limit line; and on the west by the shore of Chesapeake Bay. (b) The regulations...

  7. 33 CFR 334.170 - Chesapeake Bay, in the vicinity of Chesapeake Beach, Md.; firing range, Naval Research Laboratory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... of Chesapeake Beach, Md.; firing range, Naval Research Laboratory. 334.170 Section 334.170 Navigation..., Naval Research Laboratory. (a) The danger zone—(1) Area A. A roughly rectangular area bounded on the... established fishing structure limit line; and on the west by the shore of Chesapeake Bay. (b) The regulations...

  8. The Changing Chesapeake: An Introduction to the Natural History and Cultural History of the Chesapeake Bay. Revised.

    ERIC Educational Resources Information Center

    Chase, Valerie

    This book is about changes in the Chesapeake Bay, its animals, plants, and the surrounding land during the last 15,000 years. Some changes were caused by natural forces while others were made by people. "Chesapeake Challenges" tests the student's thinking skills. "Family Action" lists things families can do to learn more about…

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

    USGS Publications Warehouse

    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.

  10. 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

    USGS Publications Warehouse

    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.

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

    USGS Publications Warehouse

    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

  12. Geochemical history of Chesapeake Bay: Natural and anthropogenic influences

    SciTech Connect

    Hill, J.M.; Park, J.; Brush, G.

    1995-12-31

    Sediment cores, 4--5 m in length were collected at six sites in the mainstem Chesapeake Bay, as part of the NOAA National Status and Trends Program. The cores were described, X-rayed, optically scanned, and analyzed for textural parameters, Si and Al, trace metals, AVS, soluble iron, total carbon, nitrogen and sulfur. In addition, the cores were dated using Pb 210, C 14, and high temporal resolution pollen dating techniques. The cores indicate changes in the geochemical environment of the northern Chesapeake Bay, from an environment dominated by marine geochemical processes to one dominated by estuarine processes; this transition occurred approximately in the late 1930`s. Accompanying this transition is enrichment of the trace metals, as normalized to Al. Data from the cores also indicate periodic anoxic events have occurred in the main stem of the Chesapeake Bay since the time from European settlement, based on sulfur speciation and the behavior of Mn in the sediments. The behavior of the trace metals, in regard to changes through time, is strongly dependent on location in the Bay, reflecting different sources materials, and differences in geochemical environments of deposition. Changes in geochemistry of most of the cores, at approximately the same date, tentatively indicate events with Baywide influence are recorded in the sediments of these cores.

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

    EPA Science Inventory

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

    EPA Science Inventory

    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...

  15. Environmental outcome-based management: Using environmental goals and measures in the Chesapeake Bay program

    SciTech Connect

    1999-07-01

    Attention is focused on the following: Establishing Environmental Outcome-Based Management; Chesapeake Bay Program Environmental Indicators; Managing for Environmental Results; Future Directions; and Appendices.

  16. Chesapeake Bay watershed development policies and guidelines: an agreement commitment report from the Chesapeake Executive Council. Final report

    SciTech Connect

    Not Available

    1989-01-01

    Policies and guidelines intended to guide the location, design, construction, operation, and maintenance of new developments in such a manner as to preserve the quality of the Chesapeake Bay and its tributaries.

  17. Chesapeake Bay habitat restoration: A framework for action

    SciTech Connect

    1995-10-01

    This framework for action enhances existing Chesapeake Bay Program strategies, policies, and implementation plans, while providing a foundation for integrated restoration for integrated restoration activities. Based on an increased understanding of landscape and watershed processes, the framework targets the need of specific living resources in four target habitat areas through on-the-ground restoration projects. Moreover, decision-making will improve as we strengthen our ability to target, integrate, and restore key habitat functions via three phases outlined in the framework: Phase I: Facilitate habitat restoration projects, research and monitoring immediately. Phase II: Develop a process for targeting habitat restoration projects within a landscape or watershed framework. Phase II: Foster partnerships that use the expertise of federal, state, and local governments and public and private efforts to implement effective restoration projects throughout the Chesapeake Bay watershed, using the targeting information provided in Phase II.

  18. Interdisciplinary environmental project probes Chesapeake Bay down to the core

    NASA Astrophysics Data System (ADS)

    Cronin, T.; Colman, S.; Willard, D.; Kerhin, R.; Holmes, C.; Karlsen, A.; Ishman, S.; Bratton, J.

    Interrelated environmental concerns about Chesapeake Bay are being addressed in an interdisciplinary project using paleoecological and geochemical records from sediment cores to investigate Holocene climate and human encroachment. The research is looking at interannual through millennial-scale variability of bay salinity,sediment accumulation, and dissolved oxygen, temperature, and faunal and floral trends. Current and planned research is expected to result in better restoration strategies by improving our understanding of the linkages between the bay's ecosystem, climate, and land use.Chesapeake Bay, the United States' largest and most productive estuary, faces several complex environmental issues, including eutrophication and anoxia in the main channel and tributaries, high turbidity and rates of sedimentation, outbreaks of the toxic dinoflagellate Pfiesteria piscicida, and coastal erosion and submergence tied to sea-level rise. Such problems often are attributed to human activities in the bay's watershed, including pollution, urbanization, and deforestation, but it now is recognized that climatic factors also strongly influence bay salinity, temperature, and water quality.

  19. Revisiting the Chesapeake Bay phytoplankton index of biotic integrity.

    PubMed

    Johnson, Jacqueline M; Buchanan, Claire

    2014-03-01

    In 2006, a phytoplankton index of biotic integrity (PIBI) was published for Chesapeake Bay Lacouture et al. (Estuaries 29(4):598-616, 2006). The PIBI was developed from data collected during the first 18 years (1985-2002) of the Chesapeake Bay Program long-term phytoplankton and water quality monitoring programs. Combinations of up to nine phytoplankton metrics were selected to characterize bay habitat health according to plankton community condition in spring and summer seasons across four salinity zones. The independent data available at the time for index validation was not sufficient to test the PIBI because they lacked critical index parameters (pheophytin and dissolved organic carbon) and reference samples for some seasons and salinity zones. An additional 8 years of monitoring data (2003-2010) are now available to validate the original index, reassess index performance and re-examine long-term trends in PIBI conditions in the Bay. The PIBI remains sensitive to changes in nutrient and light conditions. Evaluation of the PIBI results over the entire 1985-2010 time period shows no discernible trends in the overall health of Bay habitat based on phytoplankton community conditions. This lack of overall PIBI trend appears to be a combined response to declines in water clarity and improvements in dissolved inorganic nitrogen and dissolved phosphorus conditions in the bay.

  20. The Chesapeake Bay Interpretive Buoy System: Recent Expansion and Advances

    DTIC Science & Technology

    2010-06-01

    artificial fishing and oyster reef complex in Chesapeake Bay. In addition to the standard sensor suite, the buoy is slated to have a bottom YSI 6600 water...CBIBS buoy is scheduled for deployment later in 2009 on an artificial fishing reef ; it will collect and transmit acoustic fishfinder images for remote...presentation over the internet as well as collect and transmit bottom water quality data from the reef . There have also been recent data analyses

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

    DTIC Science & Technology

    1977-12-01

    Virginia Waters Within the 145 Chesapeake Bay Study Area 7.46 Futuvr Municipal Wastewater Treatment Needs 149 7-47 Wastewater Unh Treatment Procese 165 7...They are: (:) Economic Projection Task Group (2) Water Quality and Supply, Waste Treatment , Noxious Weeds Task Group (3) Flood Control, Navigation...and History." This Appendix was prepared under the guidance of the members of the Water Quality and Supply, Waste Treatment , Noxious Weeds Task

  2. FY 2016 Grant Announcement: FY 2016 Technical Analysis and Programmatic Evaluation Support to the Chesapeake Bay Program Partnership

    EPA Pesticide Factsheets

    The U.S. Environmental Protection Agency’s Chesapeake Bay Program Office is announcing a Request for Proposals for applicants to provide the Chesapeake Bay Program partners with a proposal(s) for providing technical analysis and programmatic evaluation

  3. Chesapeake Bay subsidence monitored as wetlands loss continues

    NASA Astrophysics Data System (ADS)

    Nerem, R. S.; van Dam, T. M.; Schenewerk, M. S.

    Fragile wetland ecosystems, which support an abundance of wildlife, are being lost around the Chesapeake Bay at an alarming rate due to an increase in sea level. For example, one third of the total area of the Blackwater National Wildlife Refuge (Figure 1) (approximately 20 km2) was lost between 1938 and 1979 [Leatherman, 1992]. Approximately 4,100 km2 of the perimeter of the Chesapeake Bay are covered by wetlands of which 58% forested wetlands and 28% are salt marshes. It is likely that many factors are responsible for the wetlands loss, some that have global implications, and some that reflect local phenomena.Understanding the mechanisms responsible for wetlands deterioration and loss, however, has been impeded by the lack of adequate data including quantitative monitoring of the types and distribution of flora, Tthe boundaries of specific habitat types, and data on the spatial variations in sea level and land subsidence. This article focuses on the latter problem, which is to determine the relative roles of sea level rise and land subsidence in the region. Over the past four years, a small network of Global Positioning System (GPS) receivers have been installed near tide gauges in the Chesapeake Bay to help determine the cause of relative sea level rise in this region. These receivers are just beginning to yield results.

  4. The Relation Between Nutrient Trends in Rivers and Management Actions in the Chesapeake Bay Watershed

    NASA Astrophysics Data System (ADS)

    Phillips, S. W.

    2002-05-01

    Excess nutrients and sediment are having an adverse impact on the Chesapeake Bay ecosystem. The Chesapeake Bay Program (CBP) has been attempting to reduce the amounts of nutrients and sediment entering the Bay since the mid-1980s. Efforts have recently been accelerated because the Bay has been listed as an "impaired water body" under the Clean Water Act, meaning it must meet water-quality standards by 2010. The U.S. Geological Survey (USGS) is working with water-resource managers in Maryland and Virginia to document the loads and trends of nutrients and sediment entering the tidal portion of the Bay and to identify the factors affecting them. The factors affecting the trends of nutrients are streamflow variability, the amount of nutrient-source reductions, and the influence of watershed characteristics, including ground-water residence time. Trends in nitrogen and phosphorus loads entering the Bay show no significant decrease since the mid-1980s in the majority of the rivers entering the Bay. However, when the effect of streamflow variability is removed, decreasing trends in "flow-adjusted" concentrations suggest management practices are influencing water quality. These findings imply a need to better select the locations where these actions will account for the influence of watershed characteristics, including ground-water residence time. The USGS is working with the CBP to provide data and improve the management models used to predict the effectiveness of nutrient-reduction actions.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Alkalinity-salinity relationship in the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Cintrón Del Valle, S. M.; Najjar, R.; Herrmann, M.; Goldberger, S.; Stets, E.

    2016-12-01

    Estuaries are a significant source of atmospheric CO2, a major greenhouse gas. However, it is not known whether the Chesapeake Bay, the largest estuary in the United States, is a source or sink of CO2. Extensive pH measurements in the Bay offer the possibility of estimating the air-water CO2 flux if robust relationships between alkalinity, the acid neutralizing capacity of a water body, and salinity can be established. Here we conduct a comprehensive analysis of the alkalinity-salinity relationship in the Chesapeake Bay based on more than 18,000 alkalinity measurements made between 1985 and 2015. It was found that seven segments of the Bay could be grouped into three different linear functions, suggesting that alkalinity is conserved in the Bay and has properties that change depending on the freshwater endmember (the riverine source). The highest freshwater endmember was 1.21 mol m-3 for the Potomac River, the lowest one was 0.41 mol m-3 for the York and Rappahannock Rivers, and an intermediate freshwater endmember was 0.79 mol m-3 for the remaining four segments. For some segments, most notably the Potomac River, the scatter of the data increases with decreasing salinity, which is due, in part, to seasonal and interannual variations in the freshwater endmember.

  7. Spatiotemporal analysis of gene flow in Chesapeake Bay Diamondback Terrapins (Malaclemys terrapin).

    PubMed

    Converse, Paul E; Kuchta, Shawn R; Roosenburg, Willem M; Henry, Paula F P; Haramis, G Michael; King, Tim L

    2015-12-01

    There is widespread concern regarding the impacts of anthropogenic activities on connectivity among populations of plants and animals, and understanding how contemporary and historical processes shape metapopulation dynamics is crucial for setting appropriate conservation targets. We used genetic data to identify population clusters and quantify gene flow over historical and contemporary time frames in the Diamondback Terrapin (Malaclemys terrapin). This species has a long and complicated history with humans, including commercial overharvesting and subsequent translocation events during the early twentieth century. Today, terrapins face threats from habitat loss and mortality in fisheries bycatch. To evaluate population structure and gene flow among Diamondback Terrapin populations in the Chesapeake Bay region, we sampled 617 individuals from 15 localities and screened individuals at 12 polymorphic microsatellite loci. Our goals were to demarcate metapopulation structure, quantify genetic diversity, estimate effective population sizes, and document temporal changes in gene flow. We found that terrapins in the Chesapeake Bay region harbour high levels of genetic diversity and form four populations. Effective population sizes were variable. Among most population comparisons, estimates of historical and contemporary terrapin gene flow were generally low (m ≈ 0.01). However, we detected a substantial increase in contemporary gene flow into Chesapeake Bay from populations outside the bay, as well as between two populations within Chesapeake Bay, possibly as a consequence of translocations during the early twentieth century. Our study shows that inferences across multiple time scales are needed to evaluate population connectivity, especially as recent changes may identify threats to population persistence. © 2015 John Wiley & Sons Ltd.

  8. 3 CFR 13508 - Executive Order 13508 of May 12, 2009. Chesapeake Bay Protection and Restoration

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (USDA), Commerce (DOC), Defense (DOD), Homeland Security (DHS), the Interior (DOI), Transportation (DOT... the Chesapeake Bay; (b) are based on sound science and reflect adaptive management principles; (c) are... CHESAPEAKE BAY AS THE CLIMATE CHANGES Sec. 601. The Secretaries of Commerce and the Interior shall, to...

  9. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance 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...

  10. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance 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...

  11. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance 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...

  12. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance 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...

  13. 33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance 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...

  14. 76 FR 27967 - Safety Zone; Shore Thing and Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-13

    ... Coast Guard proposes establishing a temporary safety zone on the Chesapeake Bay in the vicinity of Ocean... action is necessary to provide for the safety of life on navigable waters during the Shore Thing and... temporary safety zone on specified waters of the Chesapeake Bay in the vicinity of Ocean View Beach...

  15. 75 FR 26226 - Executive Order 13508 Chesapeake Bay Protection and Restoration Section 203 Final Coordinated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ... estuarine ecosystem and the natural sustainability of its watershed. The EO requires that the final strategy... complementary efforts in the restoration and protection of the Chesapeake Bay and watershed. The supporting... will continue to work with the jurisdictions in the Chesapeake Bay watershed to better align actions to...

  16. APPLICATION OF TWO INDICES OF BENTHIC COMMUNITY CONDITION IN CHESAPEAKE BAY

    EPA Science Inventory

    The Chesapeake Bay Benthic Index of Biotic Integrity (B-161) and the Environmental Monitoring and Assessment Program's Virginian Province Benthic Index (EMAP-VP BI) were applied to 294 sampling events in Chesapeake Bay and the results were compared. These benthic indices are inte...

  17. Simulating hydrological and geochemical processes in a karstic watershed of the Upper Chesapeake Bay

    USDA-ARS?s Scientific Manuscript database

    Water quality improvement in the Chesapeake Bay is a grave concern. An initiative to reduce the nutrient loads to the streams in the watershed has been undertaken to attain a target total maximum daily load (TMDL) at Chesapeake Bay. A general guideline with a list of best management practices (BMPs)...

  18. Best management practices for reducing nutrient loads in a sub-watershed of Chesapeake Bay area

    USDA-ARS?s Scientific Manuscript database

    Water quality improvement in the Chesapeake Bay is a grave concern. An initiative to reduce the nutrient loads to stream has been undertaken to attain a target total maximum daily load (TMDL) at Chesapeake Bay. A general guideline with a set of best management practices (BMPs) has been in place for ...

  19. Best management practices for reducing nutrient loads in a sub-watershed of Chesapeake Bay

    USDA-ARS?s Scientific Manuscript database

    Water quality improvement in the Chesapeake Bay is a grave concern. An initiative to reduce the nutrient loads to stream has been undertaken to attain a target total maximum daily load (TMDL) at Chesapeake Bay. A general guideline with a set of best management practices (BMPs) has been in place for ...

  20. 33 CFR 334.320 - Chesapeake Bay entrance; naval restricted area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... restricted area. 334.320 Section 334.320 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.320 Chesapeake Bay entrance; naval restricted area. (a) The area. Beginning at a point on the south shore of Chesapeake Bay at...

  1. 33 CFR 334.320 - Chesapeake Bay entrance; naval restricted area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... restricted area. 334.320 Section 334.320 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.320 Chesapeake Bay entrance; naval restricted area. (a) The area. Beginning at a point on the south shore of Chesapeake Bay at...

  2. Exploring the environmental effects of shale gas development in the Chesapeake Bay watershed

    Treesearch

    Scientific and Technical Committee [STAC]. Chesapeake Bay Program

    2013-01-01

    On April 11-12, 2012, the Chesapeake Bay Program's Scientific and Technical Advisory Committee (STAC) convened an expert workshop to investigate the environmental effects of shale gas development in the Chesapeake Bay Watershed. The purpose of this workshop was to engage scientists from across the nation in a review of the state-of-the-science regarding shale gas...

  3. APPLICATION OF TWO INDICES OF BENTHIC COMMUNITY CONDITION IN CHESAPEAKE BAY

    EPA Science Inventory

    The Chesapeake Bay Benthic Index of Biotic Integrity (B-161) and the Environmental Monitoring and Assessment Program's Virginian Province Benthic Index (EMAP-VP BI) were applied to 294 sampling events in Chesapeake Bay and the results were compared. These benthic indices are inte...

  4. 33 CFR 334.310 - Chesapeake Bay, Lynnhaven Roads; navy amphibious training area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. 334.310 Section 334.310 Navigation and Navigable Waters CORPS OF....310 Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. (a) The restricted area. Beginning...

  5. 33 CFR 334.310 - Chesapeake Bay, Lynnhaven Roads; navy amphibious training area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. 334.310 Section 334.310 Navigation and Navigable Waters CORPS OF....310 Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. (a) The restricted area. Beginning...

  6. 33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... approaches to Chesapeake Bay: Precautionary area. A precautionary area is established bounded by a circle... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false In the approaches to Chesapeake Bay: Precautionary area. 167.201 Section 167.201 Navigation and Navigable Waters COAST GUARD...

  7. 33 CFR 334.350 - Chesapeake Bay off Fort Monroe, Va.; firing range danger zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Chesapeake Bay off Fort Monroe, Va.; firing range danger zone. 334.350 Section 334.350 Navigation and Navigable Waters CORPS OF....350 Chesapeake Bay off Fort Monroe, Va.; firing range danger zone. (a) The danger zone. All of the...

  8. 33 CFR 334.310 - Chesapeake Bay, Lynnhaven Roads; navy amphibious training area.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. 334.310 Section 334.310 Navigation and Navigable Waters CORPS OF....310 Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. (a) The restricted area. Beginning...

  9. 33 CFR 334.220 - Chesapeake Bay, south of Tangier Island, Va.; naval firing range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Chesapeake Bay, south of Tangier 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...

  10. 33 CFR 334.220 - Chesapeake Bay, south of Tangier Island, Va.; naval firing range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Chesapeake Bay, south of Tangier 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...

  11. 33 CFR 334.220 - Chesapeake Bay, south of Tangier Island, Va.; naval firing range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Chesapeake Bay, south of Tangier 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...

  12. 33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... approaches to Chesapeake Bay: Precautionary area. A precautionary area is established bounded by a circle... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false In the approaches to Chesapeake Bay: Precautionary area. 167.201 Section 167.201 Navigation and Navigable Waters COAST GUARD...

  13. 33 CFR 334.310 - Chesapeake Bay, Lynnhaven Roads; navy amphibious training area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. 334.310 Section 334.310 Navigation and Navigable Waters CORPS OF....310 Chesapeake Bay, Lynnhaven Roads; navy amphibious training area. (a) The restricted area. Beginning...

  14. 33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... approaches to Chesapeake Bay: Precautionary area. A precautionary area is established bounded by a circle... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false In the approaches to Chesapeake Bay: Precautionary area. 167.201 Section 167.201 Navigation and Navigable Waters COAST GUARD...

  15. 33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... approaches to Chesapeake Bay: Eastern approach. (a) A separation line is established connecting the following... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false In the approaches to Chesapeake Bay: Eastern approach. 167.202 Section 167.202 Navigation and Navigable Waters COAST GUARD, DEPARTMENT...

  16. 33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... approaches to Chesapeake Bay: Eastern approach. (a) A separation line is established connecting the following... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false In the approaches to Chesapeake Bay: Eastern approach. 167.202 Section 167.202 Navigation and Navigable Waters COAST GUARD, DEPARTMENT...

  17. 33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... approaches to Chesapeake Bay: Precautionary area. A precautionary area is established bounded by a circle... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false In the approaches to Chesapeake Bay: Precautionary area. 167.201 Section 167.201 Navigation and Navigable Waters COAST GUARD...

  18. 33 CFR 334.350 - Chesapeake Bay off Fort Monroe, Va.; firing range danger zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Chesapeake Bay off Fort Monroe, Va.; firing range danger zone. 334.350 Section 334.350 Navigation and Navigable Waters CORPS OF....350 Chesapeake Bay off Fort Monroe, Va.; firing range danger zone. (a) The danger zone. All of the...

  19. 33 CFR 167.202 - In the approaches to Chesapeake Bay: Eastern approach.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... approaches to Chesapeake Bay: Eastern approach. (a) A separation line is established connecting the following... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false In the approaches to Chesapeake Bay: Eastern approach. 167.202 Section 167.202 Navigation and Navigable Waters COAST GUARD, DEPARTMENT...

  20. 33 CFR 167.201 - In the approaches to Chesapeake Bay: Precautionary area.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... approaches to Chesapeake Bay: Precautionary area. A precautionary area is established bounded by a circle... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false In the approaches to Chesapeake Bay: Precautionary area. 167.201 Section 167.201 Navigation and Navigable Waters COAST GUARD...

  1. Managing manure for sustainable livestock production in the Chesapeake Bay Watershed

    USDA-ARS?s Scientific Manuscript database

    Manure presents one of the greatest challenges to livestock operations in the Chesapeake Bay Watershed. The Chesapeake Bay is threatened by excessive nutrient loadings and, according to the U.S. Environmental Protection Agency, manure is the source of 18% of the nitrogen and 27% of the phosphorus en...

  2. 75 FR 27552 - Guidance for Federal Land Management in the Chesapeake Bay Watershed

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-17

    ... pollution from a variety of nonpoint sources, including agricultural lands, urban and suburban areas... AGENCY Guidance for Federal Land Management in the Chesapeake Bay Watershed AGENCY: Environmental... final Guidance for Federal Land Management in the Chesapeake Bay Watershed which EPA is publishing...

  3. 75 FR 14152 - Executive Order 13508; Chesapeake Bay Protection and Restoration Section 502; Guidance for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-24

    ... Land Management in the Chesapeake Bay Watershed AGENCY: Environmental Protection Agency (EPA). ACTION... draft Guidance for Federal land management in the Chesapeake Bay watershed describing proven, cost-effective tools and practices that reduce water pollution and requests public comment. The document was...

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

    PubMed Central

    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

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

    PubMed

    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

  6. Application of the benthic index of biotic integrity to environmental monitoring in Chesapeake Bay.

    PubMed

    Llansó, Roberto J; Dauer, Daniel M; Vølstad, Jon H; Scott, Lisa C

    2003-01-01

    The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI provides Chesapeake Bay monitoring programs with a uniform tool with which to characterize bay-wide benthic community condition and assess the health of the Bay. A probability-based design permits unbiased annual estimates of areal degradation within the Chesapeake Bay and its tributaries with quantifiable precision. However, of greatest interest to managers is the identification of problem areas most in need of restoration. Here we apply the B-IBI to benthic data collected in the Bay since 1994 to assess benthic community degradation by Chesapeake Bay Program segment and water depth. We used a new B-IBI classification system that improves the reliability of the estimates of degradation. Estimates were produced for 67 Chesapeake Bay Program segments. Greatest degradation was found in areas that are known to experience hypoxia or show toxic contamination, such as the mesohaline portion of the Potomac River, the Patapsco River, and the Maryland mainstem. Logistic regression models revealed increased probability of degraded benthos with depth for the lower Potomac River, Patapsco River. Nanticoke River, lower York River, and the Maryland mainstem. Our assessment of degradation by segment and water depth provided greater resolution of relative condition than previously available, and helped define the extent of degradation in Chesapeake Bay.

  7. Web-based decision support and visualization tools for water quality management in the Chesapeake Bay watershed

    USGS Publications Warehouse

    Mullinix, C.; Hearn, P.; Zhang, H.; Aguinaldo, J.

    2009-01-01

    Federal, State, and local water quality managers charged with restoring the Chesapeake Bay ecosystem require tools to maximize the impact of their limited resources. To address this need, the U.S. Geological Survey (USGS) and the Environmental Protection Agency's Chesapeake Bay Program (CBP) are developing a suite of Web-based tools called the Chesapeake Online Assessment Support Toolkit (COAST). The goal of COAST is to help CBP partners identify geographic areas where restoration activities would have the greatest effect, select the appropriate management strategies, and improve coordination and prioritization among partners. As part of the COAST suite of tools focused on environmental restoration, a water quality management visualization component called the Nutrient Yields Mapper (NYM) tool is being developed by USGS. The NYM tool is a web application that uses watershed yield estimates from USGS SPAtially Referenced Regressions On Watershed (SPARROW) attributes model (Schwarz et al., 2006) [6] to allow water quality managers to identify important sources of nitrogen and phosphorous within the Chesapeake Bay watershed. The NYM tool utilizes new open source technologies that have become popular in geospatial web development, including components such as OpenLayers and GeoServer. This paper presents examples of water quality data analysis based on nutrient type, source, yield, and area of interest using the NYM tool for the Chesapeake Bay watershed. In addition, we describe examples of map-based techniques for identifying high and low nutrient yield areas; web map engines; and data visualization and data management techniques.

  8. The exotic mute swan (Cygnus olor) in Chesapeake Bay, USA

    USGS Publications Warehouse

    Perry, M.C.; Perry, M.C.

    2002-01-01

    The exotic mute swan (Cygnus olor) has increased its population size in Chesapeake Bay (Maryland and Virginia) to approximately 4,500 since 1962 when five swans were released in the Bay. The Bay population of mute swans now represents 30% of the total Atlantic Flyway population (12,600) and has had a phenomenal increase of 1,200% from 1986 to 1999. Unlike the tundra swans (Cygnus columbianus) that migrate to the Bay for the winter, the mute swan is a year-long resident, and, therefore, reports of conflicts with nesting native waterbirds and the consumption of submerged aquatic vegetation (SAV) have raised concerns among resource managers. Populations of black skimmers (Rynchops niger) and least terns (Sterna antillarum) nesting on beaches and oyster shell bars have been eliminated by molting mute swans. Although data on the reduction of SAV by nesting mute swans and their offspring during the spring and summer are limited, food habits data show that mute swans rely heavily on SAV during these months. Widgeon grass (Ruppia maritima) constituted 56% and eel grass (Zostera marina) constituted 43% of the gullet food of mute swans. Other SAV and invertebrates (including bryozoans, shrimp, and amphipods) formed a much smaller amount of the food percentage (1%). Invertebrates are believed to have been selected accidently within the vegetation eaten by the swans. Corn (Zea mays) fed to swans by Bay residents during the winter probably supplement limited vegetative food resources in late winter. A program to control swan numbers by the addling of eggs and the killing of adult swans has been a contentious issue with some residents of the Bay area. A management plan is being prepared by a diverse group of citizens appointed by the Governor to advise the Maryland Department of Natural Resources on viable and optimum options to manage mute swans in the Maryland portion of Chesapeake Bay. Hopefully, the implementation of the plan will alleviate the existing conflicts to the

  9. Workplan for tributary refinements to Chesapeake Bay eutrophication model package. Final report

    SciTech Connect

    Cerco, C.F.

    1994-05-01

    The Corps of Engineers, in partnership with the U.S. Environmental Protection Agency Chesapeake Bay Program Office, recently completed a three-dimensional model study of eutrophication in Chesapeake Bay and tributaries. The model package applied included an intratidal hydrodynamic model, an intertidal water-quality model, and a benthic sediment diagenesis model. This report comprises a workplan to improve model representation of Chesapeake Bay tributaries and to incorporate living resources directly into the model framework. Four tributaries have been selected for emphasis under this tributary refinements program. They are the James, York, and Rappahannock rivers, and Baltimore Harbor. The James, York, and Rappahannock were specified because tributary-specific models are required to address water-quality and living-resource benefits to be derived from nutrient reductions. Baltimore Harbor was specified because it presents unique management problems, coupled with long-term toxic impacts, which cannot be addressed in the current model framework. The time scale for the project is 4 years from initiation to completion. Anticipated commencement is April 1, 1994.

  10. Simulation of long-term trends in Chesapeake Bay eutrophication

    SciTech Connect

    Cerco, C.F.

    1995-04-01

    A predictive mathematical model was employed to examine trends in Chesapeake Bay eutrophication from 1959 to 1988. The model provided details of processes and substances for which no record existed. The simulation indicated the volume of anoxic water was largest in the decade 1969--78. Since then, anoxic volume has declined. The decline was largely due to hydrodynamic effects. In 1969--78, high runoff caused the Bay to be highly stratified and inhibited oxygen transport to bottom waters. Less runoff in the years 1979--88 diminished stratification and allowed enhanced oxygen transport to bottom waters. When only years of similar stratification were compared, an increase in anoxic volume was noted from the 1959--68 decade to the 1979--88 decade. The increase was associated with increasing nitrogen concentration in runoff from two major tributaries and with increasing chlorophyll concentration in the mainstem Bay.

  11. Cholangioma in white perch (Morone americana) from the Chesapeake Bay.

    PubMed

    Bunton, T E; Baksi, S M

    1988-01-01

    Cholangiomas found in two of 21 wild-caught white perch (Morone americana) from the Chesapeake Bay are described. The two fish were part of a study investigating a condition of abnormal hepatic copper storage in this species. The tumors were superficial, solitary masses consisting of cuboidal to columnar cells in tubuloglandular arrangement. Mild to marked peribiliary inflammation and fibrosis was seen also. Environmental pollution, the condition of abnormal copper storage, peribiliary fibrosis, and/or parasites may have contributed to the development of these tumors.

  12. Chesapeake Bay fall line toxics monitoring program: 1992 interim report

    SciTech Connect

    Dobler, E.; Nemura, A.

    1994-04-01

    The report provides an interim assessment of toxic substance loadings from the fall lines of three major tributaries, Susquehanna, Potomac and James Rivers, to the Chesapeake Bay. Results from the first six months of a one year sampling program conducted from March, 1992 to September, 1992 are described. Loadings are provided for trace metals; synthetic organic compounds; organonitrogen, organophosphorus, and organochlorine pesticides; polychlorinated biphenyl congeners; and polycyclic aromatic hydrocarbons. The program included sampling during both base and storm flow conditions. A key component of the report is the comparison of ultra clean versus standard U.S. Geological Survey protocol collection techniques for trace metals and organics.

  13. Infrared view of Chesapeake Bay showing Virginia, Maryland and Delaware

    NASA Image and Video Library

    1975-07-24

    AST-13-797 (24 July 1975) --- An infrared, near vertical view of the Chesapeake Bay area showing portions of Virginia, Maryland and Delaware, as photographed from the Apollo spacecraft in Earth orbit during the joint U.S.-USSR Apollo-Soyuz Test Project mission. Richmond and Norfolk can be seen in this picture. Tidewater Virginia covers much of this view. The photograph was taken at an altitude of 217 kilometers (135 statute miles) with a 70mm Hasselblad camera using infrared Aerochrome type 2443 Ektachrome film.

  14. Investigations on classification categories for wetlands of Chesapeake Bay using remotely sensed data

    NASA Technical Reports Server (NTRS)

    Williamson, F. S. L.

    1974-01-01

    The use of remote sensors to determine the characteristics of the wetlands of the Chesapeake Bay and surrounding areas is discussed. The objectives of the program are stated as follows: (1) to use data and remote sensing techniques developed from studies of Rhode River, West River, and South River salt marshes to develop a wetland classification scheme useful in other regions of the Chesapeake Bay and to evaluate the classification system with respect to vegetation types, marsh physiography, man-induced perturbation, and salinity; and (2) to develop a program using remote sensing techniques, for the extension of the classification to Chesapeake Bay salt marshes and to coordinate this program with the goals of the Chesapeake Research Consortium and the states of Maryland and Virginia. Maps of the Chesapeake Bay areas are developed from aerial photographs to display the wetland structure and vegetation.

  15. Conowingo Reservoir Sedimentation and Chesapeake Bay: State of the Science.

    PubMed

    Cerco, Carl F

    2016-05-01

    The Conowingo Reservoir is situated on the Susquehanna River, immediately upstream of Chesapeake Bay, the largest estuary in the United States. Sedimentation in the reservoir provides an unintended benefit to the bay by preventing sediments, organic matter, and nutrients from entering the bay. The sediment storage capacity of the reservoir is nearly exhausted, however, and the resulting increase in loading of sediments and associated materials is a potential threat to Chesapeake Bay water quality. In response to this threat, the Lower Susquehanna River Watershed Assessment was conducted. The assessment indicates the reservoir is in a state of "dynamic equilibrium" in which sediment loads from the upstream watershed to the reservoir are balanced by sediments leaving the reservoir. Increased sediment loads are not a threat to bay water quality. Increased loads of associated organic matter and nutrients are, however, detrimental. Bottom-water dissolved oxygen declines of 0.1 to 0.2 g m are projected as a result of organic matter oxidation and enhanced eutrophication. The decline is small relative to normal variations but results in violations of standards enforced in a recently enacted total maximum daily load. Enhanced reductions in nutrient loads from the watershed are recommended to offset the decline in water quality caused by diminished retention in the reservoir. The assessment exposed several knowledge gaps that require additional investigation, including the potential for increased loading at flows below the threshold for reservoir scour and the nature and reactivity of organic matter and nutrients scoured from the reservoir bottom. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  16. State of the Chesapeake Bay: second annual monitoring report, compendium. Report for January 1984-September 1985

    SciTech Connect

    Lynch, M.P.; Krome, E.C.

    1987-04-01

    The report is a summary of information collected at stations around the Chesapeake Bay. It is designed to be a more detailed/technical companion to the State Of The Bay Summary Report. It reports the results of the monitoring of the Chesapeake Bay in terms of its physical and chemical makeup (sediments, the distribution of toxics), the living resources, (plankton, benthos, submerged aquatic vegetation, birds), and the Patuxent River, as a case history.

  17. 33 CFR 162.65 - All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Atlantic Ocean south of Chesapeake Bay and all waterways tributary to the Gulf of Mexico east and south of... All waterways tributary to the Atlantic Ocean south of Chesapeake Bay and all waterways tributary to..., which are tributary to or connected by other waterways with the Atlantic Ocean south of Chesapeake...

  18. Factors affecting nutrient trends in major rivers of the Chesapeake Bay Watershed

    USGS Publications Warehouse

    Sprague, Lori A.; Langland, M.J.; Yochum, S.E.; Edwards, R.E.; Blomquist, J.D.; Phillips, S.W.; Shenk, G.W.; Preston, S.D.

    2000-01-01

    Trends in nutrient loads and flow-adjusted concentrations in the major rivers entering Chesapeake Bay were computed on the basis of water-quality data collected between 1985 and 1998 at 29 monitoring stations in the Susquehanna, Potomac, James, Rappahannock, York, Patuxent, and Choptank River Basins. Two computer models?the Chesapeake Bay Watershed Model (WSM) and the U.S. Geological Survey?s 'Spatially Referenced Regressions on Watershed attributes' (SPARROW) Model?were used to help explain the major factors affecting the trends. Results from WSM simulations provided information on temporal changes in contributions from major nutrient sources, and results from SPARROW model simulations provided spatial detail on the distribution of nutrient yields in these basins. Additional data on nutrient sources, basin characteristics, implementation of management practices, and ground-water inputs to surface water were analyzed to help explain the trends. The major factors affecting the trends were changes in nutrient sources and natural variations in streamflow. The dominant source of nitrogen and phosphorus from 1985 to 1998 in six of the seven tributary basins to Chesapeake Bay was determined to be agriculture. Because of the predominance of agricultural inputs, changes in agricultural nutrient sources such as manure and fertilizer, combined with decreases in agricultural acreage and implementation of best management practices (BMPs), had the greatest impact on the trends in flow-adjusted nutrient concentrations. Urban acreage and population, however, were noted to be increasing throughout the Chesapeake Bay Watershed, and as a result, delivered loads of nutrients from urban areas increased during the study period. Overall, agricultural nutrient management, in combination with load decreases from point sources due to facility upgrades and the phosphate detergent ban, led to downward trends in flow-adjusted nutrient concentrations atmany of the monitoring stations in the

  19. Birds and environmental contaminants in San Francisco and Chesapeake Bays

    USGS Publications Warehouse

    Ohlendorf, H.M.; Fleming, W.J.

    1988-01-01

    The direct and indirect effects of human activities, including environmental contamination, upon bird populations in San Francisco Bay and Chesapeake Bay are imperfectly understood, and few data are available. that allow a comparison of the contamination levels in birds from these two areas. Certain trace elements and organochlorine compounds have been found at sufficiently high concentrations in bird tissues or their foods to expect adverse effects in these birds, based upon results of field and laboratory studies conducted with other avian species. The decline and recovery of populations of many avian species have been recorded, including some associated with organochlorine contamination. The present paper summarizes available information on the occurrence and potential effects of contaminants upon birds in these two regions.

  20. Chesapeake Bay watershed pesticide use declines but toxicity increases.

    PubMed

    Hartwell, S Ian

    2011-05-01

    Large areas of the Chesapeake Bay, USA, watershed are in agricultural land use, but there is no baywide program to track application rates of current-use pesticides in any of the watershed jurisdictions. Watershed studies demonstrate that several pesticides are present in surface and groundwater throughout the region. Between 1985 and 2004, the Maryland Department of Agriculture conducted surveys to estimate pesticide application within the state. Application rates of the dominant insecticides and herbicides were compiled over the survey period. Toxicity of the pesticides was tabulated, and the toxic units (TU) of applied active ingredients were calculated for several animal and plant species. The total mass of pesticides being applied to the watershed declined during the survey period. Due to increasing potency of the chemicals, however, total TUs applied have remained static or have significantly increased depending on the species of bioassay test organism used to assess toxicity. Applying estimates of pesticide transport into rivers in the Mississippi River basin show that significant quantities of pesticides may be entering Chesapeake Bay. Copyright © 2011 SETAC.

  1. Wetland habitats for wildlife of the Chesapeake Bay

    USGS Publications Warehouse

    Perry, M.C.; Majumdar, S.K.; Miller, E.W.; Brenner, Fred J.

    1998-01-01

    The wetlands of Chesapeake Bay have provided the vital habitats that have sustained the impressive wildlife populations that have brought international fame to the Bay. As these wetland habitats decrease in quantity and quality we will continue to see the decline in the wildlife populations that started when European settlers first came to this continent. These declines have accelerated significantly in this century. As the human population continues to increase in the Bay watershed, one can expect that wetland habitats will continue to decline, resulting in declines in species diversity and population numbers. Although federal, state, and local governments are striving for 'no net loss' of wetlands, the results to date are not encouraging. It is unrealistic to believe that human populations and associated development can continue to increase and not adversely affect the wetland resources of the Bay. Restrictions on human population growth in the Chesapeake area is clearly the best way to protect wetland habitats and the wildlife that are dependent on these habitats. In addition, there should be more aggressive approaches to protect wetland habitats from continued perturbations from humans. More sanctuary areas should be created and there should be greater use of enhancement and management techniques that will benefit the full complement of species that potentially exist in these wetlands. The present trend in wetland loss can be expected to continue as human populations increase with resultant increases in roads, shopping malls, and housing developments. Creation of habitat for mitigation of these losses will not result in 'no net loss'. More innovative approaches should be employed to reverse the long-term trend in wetland loss by humans.

  2. Fluxes of dissolved organic carbon from Chesapeake Bay sediments

    SciTech Connect

    Burdige, D.J.; Homstead, J. )

    1994-08-01

    Benthic fluxes of dissolved organic carbon (DOC) were measured over an annual cycle at two contrasting sites in Chesapeake Bay. At an organic-rich, sulfidic site in the mesohaline portion of the Bay (site M) DOC fluxes from the sediments ranged from 1.4 to 2.9 mmol/m[sup 2]/d. Measured benthic DOC fluxes at site M corresponded to [approximately]3-13% of the depth-integrated benthic C remineralization rates ([Sigma]OCR), and agreed well with calculated diffusive DOC fluxes based on porewater DOC profiles. This agreement suggests that DOC fluxes from site M sediments were likely controlled by molecular diffusion. The second site that was studied is a heavily bioturbated site in the southern Bay (site S). The activity of macrobenthos did not appear to enhance DOC fluxes from these sediments, since measured benthic DOC fluxes (>0.5 mmol/m[sup 2]/d) were lower than those at site M. The ratios of benthic DOC fluxes to [Sigma]OCR values at site S were also slightly smaller than those observed at site M. Benthic DOC fluxes from Chesapeake Bay sediments do not appear to significantly affect the transport of DOC through this estuary, although uncertainties in the reactivity of DOC in estuaries makes this conclusion somewhat tentative at this time. However, when these results are used to make a lower limit estimate of the globally integrated benthic DOC flux from marine sediments, a value similar to that previously calculated by Burdige et al. is obtained. This observation further supports suggestions in this paper about the importance of benthic DOC fluxes in the oceanic C cycle.

  3. Uncertainty in Model Predictions of Vibrio Vulnificus Response to Climate Variability and Change: A Chesapeake Bay Case Study

    NASA Technical Reports Server (NTRS)

    Urquhart, Erin A.; Zaitchik, Benjamin F.; Waugh, Darryn W.; Guikema, Seth D.; Del Castillo, Carlos E.

    2014-01-01

    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.

  4. Uncertainty in Model Predictions of Vibrio vulnificus Response to Climate Variability and Change: A Chesapeake Bay Case Study

    PubMed Central

    Urquhart, Erin A.; Zaitchik, Benjamin F.; Waugh, Darryn W.; Guikema, Seth D.; Del Castillo, Carlos E.

    2014-01-01

    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. PMID:24874082

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

    PubMed

    Urquhart, Erin A; Zaitchik, Benjamin F; Waugh, Darryn W; Guikema, Seth D; Del Castillo, Carlos E

    2014-01-01

    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.

  6. Supplemental materials for the ICDP-USGS Eyreville A, B, and C core holes, Chesapeake Bay impact structure: Core-box photographs, coring-run tables, and depth-conversion files

    USGS Publications Warehouse

    Durand, C.T.; Edwards, L.E.; Malinconico, M.L.; Powars, D.S.

    2009-01-01

    During 2005-2006, the International Continental Scientific Drilling Program and the U.S. Geological Survey drilled three continuous core holes into the Chesapeake Bay impact structure to a total depth of 1766.3 m. A collection of supplemental materials that presents a record of the core recovery and measurement data for the Eyreville cores is available on CD-ROM at the end of this volume and in the GSA Data Repository. The supplemental materials on the CD-ROM include digital photographs of each core box from the three core holes, tables of the three coring-run logs, as recorded on site, and a set of depth-conversion programs. In this chapter, the contents, purposes, and basic applications of the supplemental materials are briefly described. With this information, users can quickly decide if the materials will apply to their specific research needs. ?? 2009 The Geological Society of America.

  7. Chesapeake Bay atmospheric deposition study. Phase 1. Final report, July 1990-June 1991

    SciTech Connect

    Baker, J.E.; Church, T.M.; Ondov, J.M.; Scudlark, J.R.; Conko, K.M.

    1992-12-01

    The purpose of the study was to determine atmospheric loadings of selected trace elements and organic compounds directly into the Chesapeake Bay. The work represents the first year of the Chesapeake Bay Atmospheric Deposition Study. A one-year study (6/90-7/91) was conducted to estimate the deposition of atmospheric contaminants to the Maryland portion of the Chesapeake Bay. The studied contaminants included the trace elements (Aluminum, Arsenic, Cadmium, Chromium, Copper, Iron, Manganese, Nickel, Lead, Selenium, and Zinc) polychlorinated biphenyl (PCBs) congeners, and polycyclic aromatic hydrocarbons (PAHs).

  8. Sediment deposition from Tropical Storm Lee in the upper Chesapeake Bay: field observations and model predictions

    NASA Astrophysics Data System (ADS)

    Palinkas, C. M.; Halka, J. P.; Li, M.; Sanford, L. P.; Cheng, P.

    2012-12-01

    Episodic flood and storm events are important drivers of sediment dynamics in estuarine and marine environments. Event-driven sedimentation has been well-documented by field and modeling studies. Yet, few studies have integrated field observations and modeling results to overcome the limitations inherent in both techniques. A unique opportunity to integrate field observations and model results was provided in late August/early September 2011 with the passage of Hurricane Irene and the remnants of Tropical Storm Lee in the Chesapeake Bay region. These storms differed in their timing, track, and impact on the Bay region - Hurricane Irene was primarily a wind/resuspension event, whereas TS Lee was a hydrological/deposition event, with the second largest discharge of the Susquehanna River on record. Because these two storms occurred within a relatively short period of time, both are potentially represented in the sediment record obtained during rapid-response cruises in September and October 2011. The resulting sediment deposit was recognized in cores using classic flood-sediment signatures (fine grain size, uniform 7Be activity, physical stratification in x-radiographs) and was found to be <4 cm, thickest in the upper Bay. Model runs conducted for TS Lee generally agreed with these estimates. One exception with physical stratification but no 7Be activity appears to be due to extreme wave activity during Hurricane Irene. Integration of observations and modeling in this case greatly improved understanding of the transport and fate of flood sediments in the Chesapeake Bay.

  9. Abundance and distribution of Synechococcus spp. and cyanophages in the Chesapeake Bay.

    PubMed

    Wang, Kui; Wommack, K Eric; Chen, Feng

    2011-11-01

    Despite the increasing knowledge of Synechococcus spp. and their co-occurring cyanophages in oceanic and coastal water, little is known about their abundance, distribution, and interactions in the Chesapeake Bay estuarine ecosystem. A 5-year interannual survey shows that Synechococcus spp. and their phages are persistent and abundant members of Chesapeake Bay microbial communities. Synechococcus blooms (10⁶ cells ml⁻¹) were often observed in summer throughout the Bay, contributing 20 to 40% of total phytoplankton chlorophyll a. The distribution of phycoerythrin-containing (PE-rich) Synechococcus cells appeared to mostly correlate with the salinity gradient, with higher abundances at higher salinities. Cyanophages infectious to Synechococcus were also abundant (up to 6 × 10⁵ viruses ml⁻¹ by the most probable number assay) during summer months in the Bay. The covariation in abundance of Synechococcus spp. and cyanophages was evident, although the latitude of observed positive correlation varied in different years, mirroring the changing environmental conditions and therefore the host-virus interactions. The impacts of cyanophages on host Synechococcus populations also varied spatially and temporally. Higher phage-related Synechococcus mortality was observed in drought years. Virus-mediated host mortality and subsequent liberation of dissolved organic matter (DOM) may substantially influence oceanic biogeochemical processing through the microbial loop as well as the microbial carbon pump. These observations emphasize the influence of environmental gradients on natural Synechococcus spp. and their phage population dynamics in the estuarine ecosystem.

  10. Assessment and significance of phytoplankton species composition within Chesapeake Bay and Virginia tributaries through a long-term monitoring program.

    PubMed

    Marshall, Harold G; Lane, Michael F; Nesius, Kneeland K; Burchardt, Lubomira

    2009-03-01

    Phytoplankton and water quality long term trends are presented from a 20-year monitoring program of Chesapeake Bay and several of its major tributaries. Increasing phytoplankton biomass and abundance are ongoing within this estuarine complex, with diatoms the dominant component, along with chlorophytes and cyanobacteria as sub-dominant contributors in the tidal freshwater and oligohaline regions. Diatoms, dinoflagellates, and cryptomonads are among the major flora downstream in the tributaries and within the Chesapeake Bay. Water quality conditions within the three tributaries have remained rather stable over this time period; while there are long term trends of reduced nutrients, increasing bottom oxygen, and decreasing water clarity for the lower Chesapeake Bay. Of note is an increasing trend of cyanobacteria biomass at 12 of the 13 stations monitored at tributary and Chesapeake Bay stations, plus the presence of 37 potentially harmful taxa reported for these waters. However, the overall status of the phytoplankton populations is presently favorable, in that it is mainly represented and dominated by taxa suitable as a major food and oxygen source within this ecosystem. Although potentially harmful taxa are present, they have not at this time exerted profound impact to the region, or replaced the diatom populations in overall dominance.

  11. Spatial and temporal distribution of two diazotrophic bacteria in the Chesapeake Bay.

    PubMed

    Short, Steven M; Jenkins, Bethany D; Zehr, Jonathan P

    2004-04-01

    The aim of this study was to initiate autecological studies on uncultivated natural populations of diazotrophic bacteria by examining the distribution of specific diazotrophs in the Chesapeake Bay. By use of quantitative PCR, the abundance of two nifH sequences (907h22 and 912h4) was quantified in water samples collected along a transect from the head to the mouth of the Chesapeake Bay during cruises in April and October 2001 and 2002. Standard curves for the quantitative PCR assays demonstrated that the relationship between gene copies and cycle threshold was linear and highly reproducible from 1 to 10(7) gene copies. The maximum number of 907h22 gene copies detected was approximately 140 ml(-1) and the maximum number of 912h4 gene copies detected was approximately 340 ml(-1). Sequence 912h4 was most abundant at the mouth of the Chesapeake Bay, and in general, its abundance increased with increasing salinity, with the highest abundances observed in April 2002. Overall, the 907h22 phylotype was most abundant at the mid-bay station. Additionally, 907h22 was most abundant in the April samples from the mid-bay and mouth of the Chesapeake Bay. Despite the fact that the Chesapeake Bay is rarely nitrogen limited, our results show that individual nitrogen-fixing bacteria have distinct nonrandom spatial and seasonal distributions in the Chesapeake Bay and are either distributed by specific physical processes or adapted to different environmental niches.

  12. 76 FR 4345 - A Method To Assess Climate-Relevant Decisions: Application in the Chesapeake Bay

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ... AGENCY A Method To Assess Climate-Relevant Decisions: Application in the Chesapeake Bay AGENCY... review draft document titled, ``A Method to Assess Climate-Relevant Decisions: Application in the.../conferences/peerreview/register-chesapeake.htm . The draft ``A Method to Assess Climate-Relevant Decisions...

  13. Derivation of Habitat-Specific Dissolved Oxygen Criteria for Chesapeake Bay and its Tidal Tributaries

    EPA Science Inventory

    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 re...

  14. Derivation of Habitat-Specific Dissolved Oxygen Criteria for Chesapeake Bay and its Tidal Tributaries

    EPA Science Inventory

    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 re...

  15. COMPARISON OF TWO INDICES OF BENTHIC COMMUNITY CONDITION IN CHESAPEAKE BAY

    EPA Science Inventory

    The Chesapeake Benthic Index of Biotic Integrity (B-IBI) and the EMAP-VP Benthic Index were applied to samples from 239 sites in Chesapeake Bay. The B-IBI weights several community measures equally and uses a simple scoring system while the EMAP-VP Benthic Index uses discriminant...

  16. Determining the age of water and long-term transport timescale of the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Döös, Kristofer; Engqvist, Anders

    2007-09-01

    The concept of age of water (AW) is applied to the Chesapeake Bay to investigate the long-term transport properties for dissolved substances. A real-time calibrated hydrodynamic Chesapeake Bay model in 3 Dimensions (CH3D), employing a boundary-fitted curvilinear grid, is used for the study. The long-term transport properties, represented by AW, are investigated under the conditions of low river inflow of 1995 and high river inflow of 1996, as well as for constant mean inflows. The influences of freshwater, density-induced circulation, and wind-induced transport on age distribution have been investigated. Model results show that river inflows, wind stress, and density-induced circulation play important roles in controlling the long-term transport in the Bay. The model results shows that it requires 120-300 days for a marked change in the characteristics of the pollutant source discharged into the Bay from the Susquehanna River to affect significantly the conditions near the mouth under different hydrodynamic conditions. An increase of river discharge results in increases of downstream residual current and gravitational circulation, and thus reduces AW. The density-induced circulation contributes to the transport substantially. The dissolved substances discharged into the Bay are transported out of the Bay more rapidly when the estuary becomes more stratified. Southeasterly and southwesterly winds have strong impacts on the transport compared to the northeasterly and northwesterly winds. The former increases lateral and vertical mixing significantly. Consequently, the gravitational circulation is reduced and the transport time is increased by 50%. The model results provide useful information for understanding the long-term transport processes in the Bay.

  17. Organic carbon balance and net ecosystem metabolism in Chesapeake Bay

    USGS Publications Warehouse

    Kemp, W.M.; Smith, E.M.; Marvin-DiPasquale, M.; Boynton, W.R.

    1997-01-01

    The major fluxes of organic carbon associated with physical transport and biological metabolism were compiled, analyzed and compared for the mainstem portion of Chesapeake Bay (USA). In addition, 5 independent methods were used to calculate the annual mean net ecosystem metabolism (NEM = production - respiration) for the integrated Bay. These methods, which employed biogeochemical models, nutrient mass-balances anti summation of individual organic carbon fluxes, yielded remarkably similar estimates, with a mean NEM of +50 g C m-2 yr-1 (?? SE = 751, which is approximately 8% of the estimated annual average gross primary production. These calculations suggest a strong cross-sectional pattern in NEM throughout the Bay, wherein net heterotrophic metabolism prevails in the pelagic zones of the main channel, while net autotrophy occurs in the littoral zones which flank the deeper central area. For computational purposes, the estuary was separated into 3 regions along the land-sea gradient: (1) the oligohaline Upper Bay (11% of total area); (2) the mesohaline Mid Bay (36% of area); and (3) the polyhaline Lower Bay (53% of area). A distinct regional trend in NEM was observed along this salinity gradient, with net here(atrophy (NEM = 87 g C m-2 yr-1) in the Upper Bay, balanced metabolism in the Mid Bay and net autotrophy (NEM = +92 g C m-2 yr-1) in the Lower Bay. As a consequence of overall net autotrophy, the ratio of dissolved inorganic nitrogen (DIN) to total organic nitrogen (TON) changed from DIN:TON = 5.1 for riverine inputs to DIN:TON = 0.04 for water exported to the ocean. A striking feature of this organic C mass-balance was the relative dominance of biologically mediated metabolic fluxes compared to physical transport fluxes. The overall ratio of physical TOC inputs (1) to biotic primary production (P) was 0.08 for the whole estuary, but varied dramatically from 2.3 in the Upper Bay to 0.03 in the Mid and Lower Bay regions. Similarly, ecosystem respiration was

  18. Modeling the Effect of Hypoxia on Macrobenthos Production in the Lower Rappahannock River, Chesapeake Bay, USA

    PubMed Central

    Sturdivant, Samuel Kersey; Brush, Mark J.; Diaz, Robert J.

    2013-01-01

    Hypoxia in Chesapeake Bay has substantially increased in recent decades, with detrimental effects on macrobenthic production; the production of these fauna link energy transfer from primary consumers to epibenthic and demersal predators. As such, the development of accurate predictive models that determine the impact of hypoxia on macrobenthic production is important. A continuous-time, biomass-based model was developed for the lower Rappahannock River, a Bay tributary prone to seasonal hypoxia. Phytoplankton, zooplankton, and macrobenthic state variables were modeled, with a focus on quantitatively constraining the effect of hypoxia on macrobenthic biomass. This was accomplished through regression with Z': a sigmoidal function between macrobenthic biomass and dissolved oxygen concentration, derived using macrobenthic data collected from the Rappahannock River during the summers of 2007 and 2008, and applied to compute hypoxia-induced mortality as a rate process. The model was verified using independent monitoring data collected by the Chesapeake Bay Program. Simulations showed that macrobenthic biomass was strongly linked to dissolved oxygen concentrations, with fluctuations in biomass related to the duration and severity of hypoxia. Our model demonstrated that hypoxia negatively affected macrobenthic biomass, as longer durations of hypoxia and greater hypoxic severity resulted in an increasing loss in biomass. This exercise represents an important contribution to modeling anthropogenically impacted coastal ecosystems, by providing an empirically constrained relationship between hypoxia and macrobenthic biomass, and applying that empirical relationship in a mechanistic model to quantify the effect of the severity, duration, and frequency of hypoxia on benthic biomass dynamics. PMID:24391904

  19. Modeling the effect of hypoxia on macrobenthos production in the lower Rappahannock River, Chesapeake Bay, USA.

    PubMed

    Sturdivant, Samuel Kersey; Brush, Mark J; Diaz, Robert J

    2013-01-01

    Hypoxia in Chesapeake Bay has substantially increased in recent decades, with detrimental effects on macrobenthic production; the production of these fauna link energy transfer from primary consumers to epibenthic and demersal predators. As such, the development of accurate predictive models that determine the impact of hypoxia on macrobenthic production is important. A continuous-time, biomass-based model was developed for the lower Rappahannock River, a Bay tributary prone to seasonal hypoxia. Phytoplankton, zooplankton, and macrobenthic state variables were modeled, with a focus on quantitatively constraining the effect of hypoxia on macrobenthic biomass. This was accomplished through regression with Z': a sigmoidal function between macrobenthic biomass and dissolved oxygen concentration, derived using macrobenthic data collected from the Rappahannock River during the summers of 2007 and 2008, and applied to compute hypoxia-induced mortality as a rate process. The model was verified using independent monitoring data collected by the Chesapeake Bay Program. Simulations showed that macrobenthic biomass was strongly linked to dissolved oxygen concentrations, with fluctuations in biomass related to the duration and severity of hypoxia. Our model demonstrated that hypoxia negatively affected macrobenthic biomass, as longer durations of hypoxia and greater hypoxic severity resulted in an increasing loss in biomass. This exercise represents an important contribution to modeling anthropogenically impacted coastal ecosystems, by providing an empirically constrained relationship between hypoxia and macrobenthic biomass, and applying that empirical relationship in a mechanistic model to quantify the effect of the severity, duration, and frequency of hypoxia on benthic biomass dynamics.

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

    NASA Astrophysics Data System (ADS)

    Griscom, D. L.

    2012-02-01

    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 during reentry. An

  1. EPA Assessments of the Subwatershed Animal Feeding Operations (AFOs) in the Chesapeake Bay Watershed

    EPA Pesticide Factsheets

    Starting in 2013, EPA is conducting assessments of AFOs within four subwatersheds in the Chesapeake Bay watershed. EPA’s assessments evaluated the compliance with state and federal requirements for reducing nitrogen, phosphorus, and sediment.

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

    USDA-ARS?s Scientific Manuscript database

    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. ...

  3. HANDBOOK: RETROFITTING POTWS FOR PHOSPHORUS REMOVAL IN THE CHESAPEAKE BAY DRAINAGE BASIN

    EPA Science Inventory

    This document assesses the technology, economics, and efficiency of phosphorus removal processes for use in the Chesapeake Bay Drainage basin (CBDB). ince phosphorus removal requirements in the CBDB vary widely with geographic location, this document discusses the feasibility of ...

  4. Report: Saving the Chesapeake Bay Watershed Requires Better Coordination of Environmental and Agricultural Resources

    EPA Pesticide Factsheets

    Report #2007-P-00004, November 20, 2006. Despite significant efforts to improve water quality in the Chesapeake Bay watershed, excess nutrients and sediment continue to impair the Bay’s water quality.

  5. Application of Remote Sensing to the Chesapeake Bay Region. Volume 2: Proceedings

    NASA Technical Reports Server (NTRS)

    Chen, W. T. (Editor); Freas, G. W., Jr. (Editor); Hickman, G. D. (Editor); Pemberton, D. A. (Editor); Wilkerson, T. D. (Editor); Adler, I. (Editor); Laurie, V. J. (Editor)

    1978-01-01

    A conference was held on the application of remote sensing to the Chesapeake Bay region. Copies of the papers, resource contributions, panel discussions, and reports of the working groups are presented.

  6. 33 CFR 165.500 - Safety/Security Zones; Chesapeake Bay, Maryland.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Safety/Security Zones; Chesapeake Bay, Maryland. (a) Definitions. (1) Certain Dangerous Cargo (CDC) means... surface to bottom, within a 500 yard radius around cruise ships and vessels transporting CDC, LNG, or...

  7. 33 CFR 165.500 - Safety/Security Zones; Chesapeake Bay, Maryland.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Safety/Security Zones; Chesapeake Bay, Maryland. (a) Definitions. (1) Certain Dangerous Cargo (CDC) means... surface to bottom, within a 500 yard radius around cruise ships and vessels transporting CDC, LNG, or...

  8. 33 CFR 165.500 - Safety/Security Zones; Chesapeake Bay, Maryland.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Safety/Security Zones; Chesapeake Bay, Maryland. (a) Definitions. (1) Certain Dangerous Cargo (CDC) means... surface to bottom, within a 500 yard radius around cruise ships and vessels transporting CDC, LNG, or...

  9. 33 CFR 165.500 - Safety/Security Zones; Chesapeake Bay, Maryland.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Safety/Security Zones; Chesapeake Bay, Maryland. (a) Definitions. (1) Certain Dangerous Cargo (CDC) means... surface to bottom, within a 500 yard radius around cruise ships and vessels transporting CDC, LNG, or...

  10. 33 CFR 165.500 - Safety/Security Zones; Chesapeake Bay, Maryland.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Safety/Security Zones; Chesapeake Bay, Maryland. (a) Definitions. (1) Certain Dangerous Cargo (CDC) means... surface to bottom, within a 500 yard radius around cruise ships and vessels transporting CDC, LNG, or...

  11. HANDBOOK: RETROFITTING POTWS FOR PHOSPHORUS REMOVAL IN THE CHESAPEAKE BAY DRAINAGE BASIN

    EPA Science Inventory

    This document assesses the technology, economics, and efficiency of phosphorus removal processes for use in the Chesapeake Bay Drainage basin (CBDB). ince phosphorus removal requirements in the CBDB vary widely with geographic location, this document discusses the feasibility of ...

  12. Willingness to Pay Survey for Chesapeake Bay Total Maximum Daily Load

    EPA Science Inventory

    A stated preference survey to collect data on households’ use of Chesapeake Bay and its watershed, and of their preferences for a variety of water quality improvements likely to follow from pollution reduction programs.

  13. Chesapeake bay submerged aquatic vegetation habitat requirements and restoration targets: A technical synthesis

    SciTech Connect

    Batiuk, R.A.; Orth, R.J.; Moore, K.A.; Dennison, W.C.; Stevenson, J.C.

    1992-12-01

    Chesapeake Bay, one of the world's largest estuaries, has experienced deterioration of water quality from nutrient enrichment, resulting in anoxic or hypoxic conditions and declines in living resources. Determination of relationships between water quality and various living resources provides a mechanism of relating anthropogenic inputs to the 'health' of Chesapeake Bay. One of the major factors contributing to the high productivity of Chesapeake Bay has been the historical abundance of submerged aquatic vegetation (SAV). SAV in Chesapeake Bay include some twenty freshwater and marine species of rooted, flowering plants. SAV provide food for waterfowl and are critical habitat for shellfish and finfish. SAV also affect nutrient cycling, sediment stability, and water turbidity. The primary objective of the SAV Technical Synthesis is to establish the quantitative levels of relevant water quality parameters necessary to support continued survival, propagation, and restoration of SAV.

  14. Willingness to Pay Survey for Chesapeake Bay Total Maximum Daily Load

    EPA Science Inventory

    A stated preference survey to collect data on households’ use of Chesapeake Bay and its watershed, and of their preferences for a variety of water quality improvements likely to follow from pollution reduction programs.

  15. Defining the extent of Chesapeake Bay toxics problems: Findings from the basin-wide strategy reevaluation

    SciTech Connect

    Batiuk, R.A.

    1994-12-31

    The Chesapeake Bay Program`s Toxics Subcommittee conducted an comprehensive reevaluation of the 1989 Basin-wide Toxics Reduction Strategy during 1992-1993. The objectives of this strategy reevaluation were to define what was known about the nature, extent, and magnitude of Bay toxics problems; what steps needed to be taken to reduce and prevent impacts from toxics; and what information still needed to be determined to support management decisions for taking additional reduction and prevention actions. The Toxics Subcommittee investigated and evaluated the complex nature of the Bay`s toxics conditions and problems through a two-year schedule of meetings, research workshops, and information-gathering forums. Key to building a technical consensus on the nature and extent of the Bay`s toxics conditions and problems was a series of seven critical issue forums. The major findings from these critical issue forums and the overall strategy reevaluation included documentation of severe localized toxicity problems, evidence of toxic effects in areas previously through to be uncontaminated, and widespread low levels of toxics in all Bay habitats sampled. These findings have resulted in a revised basinwide strategy focused on pollution prevention, regulatory program implementation, regional problem areas, and directed toxics assessments.

  16. Life-Cycle Analysis of Mid Bay and Poplar Island Projects, Chesapeake Bay, Maryland

    DTIC Science & Technology

    2005-09-01

    This report summarizes the life - cycle design and optimization of structures on three islands in Chesapeake Bay. The islands are Poplar, James, and...Barren. The life - cycle analysis is accomplished using a new method termed Empirical Life - Cycle Simulation (ELS). The historical storms selected for...analysis location, 148-year time histories of waves and water levels at 3-hour intervals are produced for use in the life - cycle analysis phase of the

  17. Long-term decline in the calanoid copepod Acartia tonsa in central Chesapeake Bay, USA: An indirect effect of eutrophication?

    NASA Astrophysics Data System (ADS)

    Kimmel, David G.; Boynton, Walter R.; Roman, Michael R.

    2012-04-01

    A long-term abundance record of the calanoid copepod Acartia tonsa in the Maryland portion of Chesapeake Bay was compiled from 1966 to 2002. A significant downward trend in the summertime abundance of Acartia tonsa was found in central Chesapeake Bay. We propose that environmental and food web changes occurred as the Chesapeake Bay became increasingly impacted by human activity which eventually led to the overall decline of A. tonsa. Environmental changes included a long-term rise in water temperature and the volume of hypoxic water during the summer. These changes occurred during the same time period as increases in chlorophyll a concentration, declines in the landings of the eastern oyster Crassostrea virginica, and declines in abundance of the sea nettle Chrysaora quinquecirrha. A CUSUM analysis showed that each time-series experienced a change point during over the past 50 years. These changes occurred sequentially, with chlorophyll a concentration increasing beginning in 1969, water temperature and hypoxic volume increasing beginning in the early 1980s, more recent Maryland C. virginica landings begin declining in the early 1980s and A. tonsa and C. quinquecirrha declining starting in 1989. A stepwise regression analysis revealed that the reduction in A. tonsa abundance appeared to be most associated with a decreasing trend in C. quinquecirrha abundance, though only when trends in the two time-series were present. The drop in C. quinquecirrha abundance is associated with reduced predation on the ctenophore, Mnemiopsis leidyi, a key predator of A. tonsa. The long-term decline of A. tonsa has likely impacted trophic transfer to fish, particularly the zooplanktivorous bay anchovy (Anchoa mitchilli). A time-series of bay anchovy juvenile index showed a negative trend and the CUSUM analysis revealed 1993 as its starting point. Total fisheries landings, excluding menhaden (Brevoortia tyrannus), in Chesapeake Bay have also declined during the same period and this

  18. Decision Making: The Chesapeake Bay. An Interdisciplinary Environmental Education Curriculum Unit. Second Edition.

    ERIC Educational Resources Information Center

    Maryland Univ., College Park. Sea Grant Program.

    As the oceans rose due to melting glaciers, the Chesapeake Bay became a crowned valley. The Bay is a biologically rich system in which the success of each species depends on the quality of water in the parts of the Bay used during its life history. With the increase in human population, technological developments associated with industrial…

  19. Decision Making: The Chesapeake Bay. An Interdisciplinary Environmental Education Curriculum Unit. Second Edition.

    ERIC Educational Resources Information Center

    Maryland Univ., College Park. Sea Grant Program.

    As the oceans rose due to melting glaciers, the Chesapeake Bay became a crowned valley. The Bay is a biologically rich system in which the success of each species depends on the quality of water in the parts of the Bay used during its life history. With the increase in human population, technological developments associated with industrial…

  20. Predator removal enhances waterbird restoration in Chesapeake Bay (Maryland)

    USGS Publications Warehouse

    Erwin, R. Michael; McGowan, Peter C.; Reese, Jan

    2011-01-01

    This report represents an update to an earlier report(Erwin et al. 2007a) on wildlife restoration on the largest dredge material island project in the United States underway in Talbot County, Maryland (Figure 1) in the mid–Chesapeake Bay region, referred to as the Paul Sarbanes Ecosystem Restoration Project at Poplar Island (www.nab.usace.army.mil/projects/Maryland/PoplarIsland/documents.html). An important component of this largescale restoration effort focused on water birds, as many of these species have undergone significant declines in the Chesapeake region over the past 30 years (Erwin et al. 2007b). The priority waterbird species include common terns (Sterna hirundo), least terns (S. antillarum), snowy egrets (Egretta thula), and ospreys (Pandion haliaetus). Although significant numbers of common terns (more than 800 pairs in 2003), least terns (62 pairs in 2003), snowy egrets (50 or more pairs by 2005), and ospreys (7 to 10 pairs) have nested on Poplar Island since early 2000, tern productivity especially had been strongly limited by a combination of red fox (Vulpes vulpes) and great horned owl (Bubo virginianus) predation. Fox trapping began in 2004, and four were removed that year; no more evidence of fox presence was found in 2005 or subsequently. The owls proved to be more problematic.

  1. Draft Genome Sequences for Seven Streptococcus parauberis Isolates from Wild Fish in the Chesapeake Bay.

    PubMed

    Haines, Ashley; Nebergall, Emily; Besong, Elvira; Council, Kimaya; Lambert, Onaysha; Gauthier, David

    2016-08-18

    Streptococcus parauberis is a pathogen of cattle and fish, closely related Streptococcus uberis and Streptococcus iniae We report the genomes of seven S. parauberis strains recovered from striped bass (Morone saxatilis) in the Chesapeake Bay. The availability of these genomes will allow comparative genomic analysis of Chesapeake Bay S. parauberis strains versus S. parauberis cultured from other animal hosts and geographic regions. Copyright © 2016 Haines et al.

  2. Conserving the forests of the Chesapeake: The status, trends, and importance of forests for the bay`s sustainable future

    SciTech Connect

    1996-09-01

    The report reviews the most current data on the status and trends of forests in the states of the Chesapeake Bay watershed. The report begins with an historical perspective of land use changes in the basin from the time of European settlement to today. It then proceeds with the status of the forests in the Bay watershed in 1996 and trends of forest change from the mid 1970`s to early 1990`s. The information is examined in light of its importance to the Bay. Finally, we present recommendations for an effective forest conservation program for the Chesapeake Bay region.

  3. Bay breeze climatology at two sites along the Chesapeake bay from 1986-2010: Implications for surface ozone.

    PubMed

    Stauffer, Ryan M; Thompson, Anne M

    Hourly surface meteorological measurements were coupled with surface ozone (O3) mixing ratio measurements at Hampton, Virginia and Baltimore, Maryland, two sites along the Chesapeake Bay in the Mid-Atlantic United States, to examine the behavior of surface O3 during bay breeze events and quantify the impact of the bay breeze on local O3 pollution. Analyses were performed for the months of May through September for the years 1986 to 2010. The years were split into three groups to account for increasingly stringent environmental regulations that reduced regional emissions of nitrogen oxides (NOx): 1986-1994, 1995-2002, and 2003-2010. Each day in the 25-year record was marked either as a bay breeze day, a non-bay breeze day, or a rainy/cloudy day based on the meteorological data. Mean eight hour (8-h) averaged surface O3 values during bay breeze events were 3 to 5 parts per billion by volume (ppbv) higher at Hampton and Baltimore than on non-bay breeze days in all year periods. Anomalies from mean surface O3 were highest in the afternoon at both sites during bay breeze days in the 2003-2010 study period. In conjunction with an overall lowering of baseline O3 after the 1995-2002 period, the percentage of total exceedances of the Environmental Protection Agency (EPA) 75 ppbv 8-h O3 standard that occurred on bay breeze days increased at Hampton for 2003-2010, while remaining steady at Baltimore. These results suggest that bay breeze circulations are becoming more important to causing exceedance events at particular sites in the region, and support the hypothesis of Martins et al. (2012) that highly localized meteorology increasingly drives air quality events at Hampton.

  4. Nitrate export from forested watersheds in the Chesapeake Bay Region, USA

    SciTech Connect

    Bricker, O.P.; Kuebler, A.; Rice, K.C.; Anderson, R.T.; Kennedy, M.M.

    1994-12-31

    Current levels of nitrogen inputs to the Chesapeake Bay exceed the ecological demand, resulting in eutrophication and algal blooms which degrade water quality. The Chesapeake Bay receives nitrogen compounds from a variety of sources. Previously, much attention had been focused on point source contributions such as sewage treatment plants and industrial discharges. More recently, however, inputs from atmospheric deposition and non-point sources have been considered. Land use practices vary widely within the Chesapeake Bay watershed, however, the largest portion is forested. Given that forested watersheds occupy a large area of the Chesapeake Bay drainage system, export of nitrogen from forested watersheds could potentially play an important role in the nitrogen balance. Here, examine the nitrate input/output budgets for eight forested headwater watersheds in the Chesapeake Bay drainage, several of which have a 10-year record of chemical data. The authors explore annual and seasonal input/output budgets for these watersheds and, at several sites, define the variability in nitrate export during episodic events Seasonal and episodic information on nitrate export may be useful to watershed managers in designing and applying techniques for minimizing nitrate export from these systems. Comparison of the behavior of nitrate in these systems, and with forested watersheds in other regions across a deposition gradient, will help to elucidate the factors that control nitrate export from forested watersheds. This information will better define the expected nitrate exports from forested watersheds and contribute to improving the confidence limits of models of nutrient loading to the Chesapeake Bay.

  5. Biodegradation of petroleum by Chesapeake Bay sediment bacteria.

    PubMed

    Walker, J D; Colwell, R R; Petrakis, L

    1976-03-01

    Chesapeake Bay sediment bacteria from oil-contaminated and oil-free environments were compared for their ability to utilize a South Louisiana crude oil. Preferential solubility, column chromatography, gas-liquid chromatography, and computerized mass spectrometry were used to provide new and useful information regarding biodegradation of fractions and components of the crude oil. Vibrio, Pseudomonas, and Acinetobacter spp. were isolated from the culture inoculated with oil-contaminated sediment, whereas coryneforms and Pseudomonas spp. were isolated from the culture inoculated with oil-free sediment. Microorganisms from the oil-free sediment produced greater quantities of polar n-pentane-insoluble components (asphaltenes) after degradation, whereas microorganisms from the oil-contaminated sediments provided greater degradation of saturated and aromatic hydrocarbons.

  6. Coordinated Field Campaigns in Chesapeake Bay and Gulf of Mexico

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio; Novak, Michael; Tzortziou, Maria A.

    2015-01-01

    NASA's GEOstationary Coastal and Air Pollution Events (GEO-CAPE) mission concept recommended by the U.S. National Research Council (2007) focuses on measurements of atmospheric trace gases and aerosols and aquatic coastal ecology and biogeochemistry from geostationary orbit (35,786 km altitude). Two GEO-CAPE-sponsored multi-investigator ship-based field campaigns were conducted to coincide with the NASA Earth Venture Suborbital project DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) field campaigns: (1) Chesapeake Bay in July 2011 and (2) northwestern Gulf of Mexico in September 2013. Goal: to evaluate whether GEO-CAPE coastal mission measurement and instrument requirements are optimized to address science objectives while minimizing ocean color satellite sensor complexity, size and cost - critical mission risk reduction activities. NASA continues to support science studies related to the analysis of data collected as part of these coordinated field campaigns and smaller efforts.

  7. Aquatic-surface microlayer contamination in Chesapeake Bay. Final report

    SciTech Connect

    Hardy, J.T.; Crecelius, B.A.; Antrim, L.D.; Kiesser, S.L.; Broadhurst, V.L.

    1987-08-01

    The boundary between the atmosphere and the aquatic environment is an important biological habitat and a collection point for pollutants. The eggs and larvae of many fish and shellfish species float on, or come in contact with, the water surface throughout their early development. The aquatic-surface microlayer serves as a concentration point for metal and organic contaminants that have low water solubility or are associated with floatable particles. Coal-fired power plants may release organic and metal contaminants into the environment that subsequently concentrate on the water surface. The objectives of this study were to (1) determine the present degree of aquatic surface microlayer pollution at selected sites in Chesapeake Bay, and (2) provide a preliminary evaluation of sources (including power plants) contributing to any observed contamination.

  8. Water color and circulation southern Chesapeake Bay, part 1

    NASA Technical Reports Server (NTRS)

    Nichols, M. M.; Gordon, H. H.

    1975-01-01

    Satellite imagery from two EREP passes over the Rappahannock Estuary of the Chesapeake region is analyzed to chart colored water types, to delineate color boundaries and define circulatory patterns. Surface observations from boats and helicopters concurrent with Skylab overpass define the distributions of suspended sediment, transparency, temperature, salinity, phytoplankton, color of suspended material and optical ratio. Important features recorded by the imagery are a large-scale turbidity maximum and massive red tide blooms. Water movement is revealed by small-scale mixing patterns and tidal plumes of apparent sediment-laden water. The color patterns broadly reflect the bottom topography and the seaward gradient of suspended material between the river and the bay. Analyses of red, green and natural color photos by microdensitometry demonstrate the utility of charting water color types of potential use for managing estuarine water quality. The Skylab imagery is superior to aerial photography and surface observations for charting water color.

  9. Chesapeake Bay Fall Line Toxics Monitoring Program: 1994 final report

    SciTech Connect

    1994-12-31

    The Fall Line Toxics Program for 1994 is a continuation of a long term effort to make accurate load estimates of contaminants entering the Chesapeake Bay from the non-tidal portion of the watershed. This program has identified nine major tributaries on which to make fall line load estimates. The 1994 Fall Line Toxics Program consisted of two components. First, the Susquehanna River was sampled from February 1994 through January 1995 during baseflow and stormflow conditions. Secondly, eight additional tributaries were sampled twice synoptically, once in Spring, 1994 and once in Fall, 1994. This report presents the results of both components. Samples were analyzed for dissolved and particulate fractions of trace elements and organic constituents. Concentration data and extensive quality assurance results are presented.

  10. 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.

    PubMed

    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.

  11. Catastrophic anoxia in the Chesapeake Bay in 1984

    SciTech Connect

    Seliger, H.H.; Boggs, J.A.; Biggley, W.H.

    1985-04-05

    In 1984, four climatic sequences combined to produce what may be a major anoxic catastrophe in the northern Chesapeake Bay, sufficient to severely threaten the major benthic species. These sequences are (1) the highest late-winter streamflow on record from the Susquehanna River watershed; (2) streamflows from the Susquehanna River for the consecutive months of June, July, and August that are higher by 2 standard deviations than the respective monthly mean values measured over the last 34 years; (3) a stationary high in August off the Atlantic Coast; and (4) an absence of strong storm events in summer. An empirical equation is proposed for the prediction of the monthly trend of dissolved oxygen decrease in terms of a temperature-dependent subpycnoclinal respiration and a modified estuarine Richardson number. As of 23 August 1984, the summer pycnocline of the northern bay had eroded upward from its historically recorded depth below 10 meters to an abnormally shallow 5 meters, with higher stratification than in earlier years. Dissolved oxygen concentrations directly below the pycnocline decreased to zero during June, 2 months earlier than for previous wet years. At present, oxygen-deficient waters containing significant concentrations of hydrogen sulfide have penetrated into Eastern Bay and the Choptank and Potomac rivers. Because most remaining shellfish-spawning and seed-bed areas in these tributaries are located at depths between 4 and 8 meters, the continued absence of major destratifying events will prolong the present anoxic trend and may result in high benthic mortalities. 11 references, 2 figures.

  12. Catastrophic anoxia in the chesapeake bay in 1984.

    PubMed

    Seliger, H H; Boggs, J A; Biggley, W H

    1985-04-05

    In 1984, four climatic sequences combined to produce what may be a major anoxic catastrophe in the northern Chesapeake Bay, sufficient to severely threaten the major benthic species. These sequences are (i) the highest late-winter streamflow on record from the Susquehanna River watershed; (ii) streamflows from the Susquehanna River for the consecutive months of June, July, and August that are higher by 2 standard deviations than the respective monthly mean values measured over the last 34 years; (iii) a stationary high in August off the Atlantic Coast; and (iv) an absence of strong storm events in summer. An empirical equation is proposed for the prediction of the monthly trend of dissolved oxygen decrease in terms of a temperature-dependent subpycnoclinal respiration and a modified estuarine Richardson number. As of 23 August 1984, the summer pycnocline of the northern bay had eroded upward from its historically recorded depth below 10 meters to an abnormally shallow 5 meters, with higher stratification than in earlier years. Dissolved oxygen concentrations directly below the pycnocline decreased to zero during June, 2 months earlier than for previous wet years. At present, oxygen-deficient waters containing significant concentrations of hydrogen sulfide have penetrated into Eastern Bay and the Choptank and Potomac rivers. Because most remaining shellfish-spawning and seed-bed areas in these tributaries are located at depths between 4 and 8 meters, the continued absence of major destratifying events will prolong the present anoxic trend and may result in high benthic mortalities.

  13. An evaluation of the utilization of remote sensing in resource and environmental management of the Chesapeake Bay region

    NASA Technical Reports Server (NTRS)

    Fuller, D. B.; Harmon, D. M.; Fuller, K. B.

    1976-01-01

    A nine-month study was conducted to assess the effectiveness of the NASA Wallops Chesapeake Bay Ecological Program in remote sensing. The study consisted of a follow-up investigation and information analysis of actual cases in which remote sensing was utilized by management and research personnel in the Chesapeake Bay region. The study concludes that the NASA Wallops Chesapeake Bay Ecological Program is effective, both in terms of costs and performance.

  14. Structure, age and origin of the bay-mouth shoal deposits, Chesapeake Bay, Virginia

    USGS Publications Warehouse

    Colman, Steven M.; Berquist, C.R.; Hobbs, C. H.

    1988-01-01

    The mouth of Chesapeake Bay contains a distinctive shoal complex and related deposits that result from the complex interaction of three different processes: (1) progradation of a barrier spit at the southern end of the Delmarva Peninsula, (2) strong, reversing tidal currents that transport and rework sediment brought to the bay mouth from the north, and (3) landward (bayward) net non-tidal circulation and sediment transport. Together, these processes play a major role in changing the configuration of the estuary and filling it with sediment. The deposits at the mouth of the bay hold keys both to the evolution of the bay during the Holocene transgression and to the history of previous generations of the bay. The deposit associated with the shoals at the mouth of the bay, the bay-mouth sand, is a distinct stratigraphic unit composed mostly of uniform, gray, fine sand. The position and internal structure of the unit shows that it is related to near-present sea level, and thus is less than a few thousand years old. The processes affecting the upper surface of the deposit and the patterns of erosion and deposition at this surface are complex, but the geometry and structure of the deposit indicate that it is a coherent unit that is prograding bayward and tending to fill the estuary. The source of the bay-mouth sand is primarily outside the bay in the nearshore zone of the Delmarva Peninsula and on the inner continental shelf. The internal structure of the deposit, its surface morphology, its heavy-mineral composition, bottom-current studies, comparative bathymetry, and sediment budgets all suggest that sand is brought to the bay mouth by southerly longshore drift along the Delmarva Peninsula and then swept into the bay. In addition to building the southward- and bayward-prograding bay-mouth sand, these processes result in sand deposition tens of kilometers into the bay. ?? 1988.

  15. Evolution of sediment plumes in the Chesapeake bay and implications of climate variability.

    PubMed

    Zheng, Guangming; DiGiacomo, Paul M; Kaushal, Sujay S; Yuen-Murphy, Marilyn A; Duan, Shuiwang

    2015-06-02

    Fluvial sediment transport impacts fisheries, marine ecosystems, and human health. In the upper Chesapeake Bay, river-induced sediment plumes are generally known as either a monotonic spatial shape or a turbidity maximum. Little is known about plume evolution in response to variation in streamflow and extreme discharge of sediment. Here we propose a typology of sediment plumes in the upper Chesapeake Bay using a 17 year time series of satellite-derived suspended sediment concentration. On the basis of estimated fluvial and wind contributions, we define an intermittent/wind-dominated type and a continuous type, the latter of which is further divided into four subtypes based on spatial features of plumes, which we refer to as Injection, Transport, Temporary Turbidity-Maximum, and Persistent Turbidity-Maximum. The four continuous types exhibit a consistent sequence of evolution within 1 week to 1 month following flood events. We also identify a "shift" in typology with increased frequency of Turbidity-Maximum types before and after Hurricane Ivan (2004), which implies that extreme events have longer-lasting effects upon estuarine suspended sediment than previously considered. These results can serve as a diagnostic tool to better predict distribution and impacts of estuarine suspended sediment in response to changes in climate and land use.

  16. Ecological risk assessment of copper and cadmium in surface waters of Chesapeake Bay watershed

    SciTech Connect

    Hall, L.W. Jr.; Scott, M.C.; Killen, W.D.

    1998-06-01

    This ecological risk assessment was designed to characterize risk of copper and cadmium exposure in the Chesapeake Bay watershed by comparing the probability distributions of environmental exposure concentrations with the probability distributions of species response data determined from laboratory studies. The overlap of these distributions was a measure of risk to aquatic life. Dissolved copper and cadmium exposure data were available from six primary data sources covering 102 stations in 18 basins in the Chesapeake Bay watershed from 1985 through 1996. Highest environmental concentrations of copper (based on 90th percentiles) were reported in the Chesapeake and Delaware (C and D) Canal, Choptank River, Middle River, and Potomac River; the lowest concentrations of copper were reported in the lower and middle mainstem Chesapeake Bay and Nanticoke River. Based on the calculation of 90th percentiles, cadmium concentrations were highest in the C and D Canal, Potomac River, Upper Chesapeake Bay, and West Chesapeake watershed. Lowest environmental concentrations of cadmium were reported in the lower and middle mainstem Chesapeake Bay and Susquehanna River. The ecological effects data used for this risk assessment were derived primarily from acute copper and cadmium laboratory toxicity tests conducted in both fresh water and salt water; chronic data were much more limited. The 10th percentile (concentration protecting 90% of the species) for all species derived from the freshwater acute copper toxicity database was 8.3 {micro}g/L. For acute saltwater copper data, the 10th percentile for all species was 6.3 {micro}g/L copper. The acute 10th percentile for all saltwater species was 31.7 {micro}g/L cadmium. Highest potential ecological risk from copper exposures was reported in the C and D Canal area of the northern Chesapeake Bay watershed.

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

    NASA Astrophysics Data System (ADS)

    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

  18. Lagrangian circulation study near Cape Henry, Virginia. [Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1981-01-01

    A study of the circulation near Cape Henry, Virginia, was made using surface and seabed drifters and radar tracked surface buoys coupled to subsurface drag plates. Drifter releases were conducted on a line normal to the beach just south of Cape Henry. Surface drifter recoveries were few; wind effects were strongly noted. Seabed drifter recoveries all exhibited onshore motion into Chesapeake Bay. Strong winds also affected seabed recoveries, tending to move them farther before recovery. Buoy trajectories in the vicinity of Cape Henry appeared to be of an irrotational nature, showing a clockwise rotary tide motion. Nearest the cape, the buoy motion elongated to almost parallel depth contours around the cape. Buoy motion under the action of strong winds showed that currents to at least the depth of the drag plates substantially are altered from those of low wind conditions near the Bay mouth. Only partial evidence could be found to support the presence of a clockwise nontidal eddy at Virginia Beach, south of Cape Henry.

  19. Low prevalence of splenic mycobacteriosis in migratory striped bass Morone saxatilis from North Carolina and Chesapeake Bay, U.S.A.

    PubMed

    Matsche, Mark A; Overton, Anthony; Jacobs, John; Rhodes, Matt R; Rosemary, Kevin M

    2010-07-01

    Mycobacteriosis is a chronic bacterial disease causing an ongoing epizootic in striped bass Morone saxatilis in Chesapeake Bay, U.S.A. Prevalence of disease is high in pre-migratory fish, and multiple species of Mycobacterium spp. have been isolated. However, prevalence of mycobacteriosis in the coastal migratory population is unknown and is of concern to multiple coastal states, as disease-related mortality may impact the long-term health of the population. Histological examinations of spleens collected from fish caught by recreational anglers during the winter fishery in coastal North Carolina (2005-2006, n=249) and during the spring fishery in Chesapeake Bay (2006, n=120) indicated a low prevalence of mycobacteriosis (6.8% of all fish examined) in comparison to smaller, pre-migratory Chesapeake Bay fish. Genus-level PCR and subsequent sequencing of the 16-23S intergenic transcribed spacer (ITS) region revealed that all bacteria were phylogenetically related, but species is unknown. Location of survey, gender of fish, and total length of fish had no significant effect on prevalence of mycobacteriosis, parasitic granulomas, or the density of splenic granulomas (p > 0.05). These results may indicate that either granulomas resolve after Chesapeake Bay fish enter the coastal migratory population, or that there is disease-related mortality among pre-migratory Chesapeake Bay fish.

  20. Response of the Chesapeake Bay water quality model to loading scenarios (a report of the modeling Subcommittee, Chesapeake Bay Program Office, Annapolis, MD). Technology transfer report

    SciTech Connect

    Thomann, R.V.; Collier, J.R.; Butt, A.; Casman, E.; Linker, L.C.

    1994-01-01

    A modeling framework was constructed for the Chesapeake Bay system to provide a credible basis to assist the decision-making process and to further the understanding of Bay water quality processes and the sensitivity of such processes to external nutrient loading. The modeling structure consists of a Watershed Model to generate nutrient loads from the Bay sub-basins; a three-dimensional, time variable hydrodynamic model; and a three-dimensional, time variable model of water quality coupled to a model of sediment chemistry. Extensive calibration analyses of the entire modeling structure was conducted using data collected primarily during a three year period from 1984-1986. The Chesapeake Bay Program Modeling Subcommittee completed its initial review of the Chesapeake Bay Water Quality Model (CBWQM) calibration in May 1991 and concluded the model could provide useful information to the Bay community, especially with respect to dissolved oxygen problems in the deep water of the main Bay. Final calibration of the CBWQM was completed in January 1992.

  1. Comments on recent canvasback habitat trends and threats on Chesapeake Bay

    USGS Publications Warehouse

    Perry, M.C.

    1976-01-01

    During the last 22 years, the North American winter population of canvasbacks has fluctuated from 481,000 in 1955 to 179,000 in 1972. The Chesapeake Bay population has averaged 33 percent of the North American population and 64 percent of the Atlantic Flyway population. In Maryland, significant annual fluctuations have been recorded between the eastern and western shore of Chesapeake Bay. In 1968, 11 percent of the Bay canvasbacks were on the western shore, whereas in 1971, 87 percent of the birds wintered in this area. This increase in 1971 is believed to be in response to large populations of small Rangia cuneata clams. I n recent years, mortality of small clams and reduced spawning have resulted in a larger size class for Rangia making them less desirable as a waterfowl food. Canvasback populations in 1975 and 1976 were more dispersed in Chesapeake Bay when the predominant food of canvasbacks was Macoma balthica. In the last 5 years, the number of canvasbacks wintering in Chesapeake Bay has declined slightly, while the North American and Atlantic Flyway populations have increased. Increases have been noted in New Jersey and North Carolina. This trend may indicate that the quality of canvasback habitat in Chesapeake Bay is declining at a faster rate than other areas along the Atlantic coast.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Sorption and bioreduction of hexavalent uranium at a military facility by the Chesapeake Bay.

    PubMed

    Dong, Wenming; Xie, Guibo; Miller, Todd R; Franklin, Mark P; Oxenberg, Tanya Palmateer; Bouwer, Edward J; Ball, William P; Halden, Rolf U

    2006-07-01

    Directly adjacent to the Chesapeake Bay lies the Aberdeen Proving Ground, a U.S. Army facility where testing of armor-piercing ammunitions has resulted in the deposition of >70,000 kg of depleted uranium (DU) to local soils and sediments. Results of previous environmental monitoring suggested limited mobilization in the impact area and no transport of DU into the nation's largest estuary. To determine if physical and biological reactions constitute mechanisms involved in limiting contaminant transport, the sorption and biotransformation behavior of the radionuclide was studied using geochemical modeling and laboratory microcosms (500 ppb U(VI) initially). An immediate decline in dissolved U(VI) concentrations was observed under both sterile and non-sterile conditions due to rapid association of U(VI) with natural organic matter in the sediment. Reduction of U(VI) to U(IV) occurred only in non-sterile microcosms. In the non-sterile samples, intrinsic bioreduction of uranium involved bacteria of the order Clostridiales and was only moderately enhanced by the addition of acetate (41% vs. 56% in 121 days). Overall, this study demonstrates that the migration of depleted uranium from the APG site into the Chesapeake Bay may be limited by a combination of processes that include rapid sorption of U(VI) species to natural organic matter, followed by slow, intrinsic bioreduction to U(IV).

  4. Dynamics of the Chesapeake Bay outflow plume: Realistic plume simulation and its seasonal and interannual variability

    NASA Astrophysics Data System (ADS)

    Jiang, Long; Xia, Meng

    2016-02-01

    The three-dimensional unstructured-grid Finite Volume Coastal Ocean Model (FVCOM) was implemented for Chesapeake Bay and its adjacent coastal ocean to delineate the realistic Chesapeake Bay outflow plume (CBOP) as well as its seasonal and interannual variability. Applying the appropriate horizontal and vertical resolution, the model exhibited relatively high skill in matching the observational water level, temperature, and salinity from 2003 to 2012. The simulated surface plume structure was verified by comparing output to the HF radar current measurements, earlier field observations, and the MODIS and AVHRR satellite imagery. According to the orientation, shape, and size of the CBOP from both model snapshots and satellite images, five types of real-time plume behavior were detected, which implied strong regulation by wind and river discharge. In addition to the episodic plume modulation, horizontal and vertical structure of the CBOP exhibited variations on seasonal and interannual temporal scales. Seasonally, river discharge with a 1 month lag was primarily responsible for the surface plume area variation, while the plume thickness was mainly correlated to wind magnitude. On the interannual scale, river discharge was the predominant source of variability in both surface plume area and depth; however, the southerly winds also influenced the offshore plume depth. In addition, large-scale climate variability, such as the North Atlantic Oscillation, could potentially affect the plume signature in the long term by altering wind and upwelling dynamics, underlining the need to understand the impacts of climate change on buoyant plumes, such as the CBOP.

  5. Climate effects on phytoplankton floral composition in Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Harding, L. W.; Adolf, J. E.; Mallonee, M. E.; Miller, W. D.; Gallegos, C. L.; Perry, E. S.; Johnson, J. M.; Sellner, K. G.; Paerl, H. W.

    2015-09-01

    Long-term data on floral composition of phytoplankton are presented to document seasonal and inter-annual variability in Chesapeake Bay related to climate effects on hydrology. Source data consist of the abundances of major taxonomic groups of phytoplankton derived from algal photopigments (1995-2004) and cell counts (1985-2007). Algal photopigments were measured by high-performance liquid chromatography (HPLC) and analyzed using the software CHEMTAX to determine the proportions of chlorophyll-a (chl-a) in major taxonomic groups. Cell counts determined microscopically provided species identifications, enumeration, and dimensions used to obtain proportions of cell volume (CV), plasma volume (PV), and carbon (C) in the same taxonomic groups. We drew upon these two independent data sets to take advantage of the unique strengths of each method, using comparable quantitative measures to express floral composition for the main stem bay. Spatial and temporal variability of floral composition was quantified using data aggregated by season, year, and salinity zone. Both time-series were sufficiently long to encompass the drought-flood cycle with commensurate effects on inputs of freshwater and solutes. Diatoms emerged as the predominant taxonomic group, with significant contributions by dinoflagellates, cryptophytes, and cyanobacteria, depending on salinity zone and season. Our analyses revealed increased abundance of diatoms in wet years compared to long-term average (LTA) or dry years. Results are presented in the context of long-term nutrient over-enrichment of the bay, punctuated by inter-annual variability of freshwater flow that strongly affects nutrient loading, chl-a, and floral composition. Statistical analyses generated flow-adjusted diatom abundance and showed significant trends late in the time series, suggesting current and future decreases of nutrient inputs may lead to a reduction of the proportion of biomass comprised by diatoms in an increasingly diverse

  6. Selected data for sediment cores collected in Chesapeake Bay in 1996 and 1998

    USGS Publications Warehouse

    Baucom, P.C.; Bratton, J.F.; Colman, Steven M.; Moore, Johnnie N.; King, John W.; Seal, Chip; Seal, R.R.

    2001-01-01

    As part of a study of recent history of the Chesapeake Bay ecosystem, one- to eight- meter long sediment cores were obtained from the mesohaline section of the Chesapeake Bay between the mouths of the Potomac and Rhode Rivers. The sediments consist of three lithofacies: coarse-grained channel deposits, restricted-estuary sands and muds, and open-estuary muds. Water content, biogenic silica, magnetic susceptibility, trace metals, and nutrients (carbon, nitrogen, and their isotopes) were measured in the cores. Biogenic silica, trace-metal, and nutrient data provide a strong basis for discussing past primary productivity and water-column anoxia in the bay.

  7. Chesapeake Bay dissolved oxygen goal for restoration of living resource habitats. Reevaluation report No. 7C

    SciTech Connect

    Jordan, S.; Stenger, C.; Olson, M.; Batiuk, R.; Mountford, K.

    1992-12-01

    Section I provides an introduction, including background on the need for developing this document, report objectives, and a brief summary of characteristics of dissolved oxygen in Chesapeake Bay. Sections II and III in the document establish and defend a dissolved oxygen restoration goal for Chesapeake Bay, based on extensive analysis and evaluation of research data. Section IV provides applications of the Goal and target concentrations to monitoring and modeling information. This section explains the relationships developed and how to use them to evaluate present and projected dissolved oxygen conditions in the Bay and its tributaries. Appendix B contains further details of the statistical approach used in this analysis.

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

    SciTech Connect

    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

  9. Organic matter remineralization predominates phosphorus cycling in the mid-Bay sediments in the Chesapeake Bay.

    PubMed

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

    2015-05-19

    Chesapeake Bay, the largest and most productive estuary in the U.S., suffers from varying degrees of water quality issues fueled by both point and nonpoint nutrient sources. Restoration of the Bay is complicated by the multitude of nutrient sources, their variable inputs, and complex interaction between imported and regenerated nutrients. 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 provides information useful in identifying the exchange of dissolved constituents across the sediment-water interface as well as helps to better constrain the mechanisms and processes controlling the coupling between sediments and the overlying waters. Here we used phosphate oxygen isotope ratios (δ(18)O(P)) in concert with sediment chemistry, X-ray diffraction, and Mössbauer spectroscopy on sediments retrieved from an organic rich, sulfidic site in the mesohaline portion of the mid-Bay to identify sources and pathway of sedimentary P cycling and to infer potential feedbacks on bottom water hypoxia and surface water eutrophication. Authigenic phosphate isotope data suggest 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. This indicates that the excess inorganic P generated by remineralization should have overwhelmed any pore water and/or bottom water because only a fraction of this precipitates as authigenic P. This is the first research that identifies the predominance of remineralization pathway and recycling of P within the Chesapeake Bay. Therefore, these results have significant implications on the current understanding of sediment P cycling and P exchange across the sediment-water interface in the Bay, particularly in terms of the sources and pathways of P that sustain hypoxia

  10. Contribution of atmospheric nitrate deposition to nitrate loading in the Chesapeake Bay. Final report

    SciTech Connect

    Tyler, M.

    1988-12-01

    Recent studies have suggested that nitrate introduced into the Chesapeake Bay via atmospheric deposition may be a significant source of excess nutrients. In order to determine if concerns about atmospheric deposition are justified, modeled estimates of wetfall nitrate deposition over the Chesapeake Bay basin, based on monitoring data collected in 1984, were used to estimate basin-wide nitrate loading (1.38 x 10/sup 8/ kg) over the land area of the basin. Estimates of transfer coefficients and nitrate loadings to the Bay for various land-use categories were also calculated, using figures developed by the EPA Chesapeake Bay Program. The conservative nature of assumptions made in developing these figures suggests that the actual percentage contribution of atmospheric nitrate deposition may be lower than the estimated value.

  11. 77 FR 19570 - Special Local Regulation for Marine Events, Chesapeake Bay Workboat Race, Back River, Messick...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ... Bay Workboat Race, Back River, Messick Point; Poquoson, VA AGENCY: Coast Guard, DHS. ACTION: Notice of... Chesapeake Bay Workboat Race, a series of boat races to be held on the waters of Back River, Poquoson... competitive races on the waters of the Back River. This regulation is necessary to provide for the safety of...

  12. Chesapeake bay goal line 2025: Opportunities for enhancing agricultural conservation conference report

    USDA-ARS?s Scientific Manuscript database

    The Total Maximum Daily Load (TMDL) for the Chesapeake Bay and its tributaries has been developed by the Environmental Protection Agency (EPA) and has led sub-watershed managers within the Bay watershed to develop Watershed Improvement Plans (WIPs). The goals of the WIPs are to delineate nutrient a...

  13. Decision Making/The Chesapeake Bay. An Interdisciplinary Environmental Education Curriculum Unit.

    ERIC Educational Resources Information Center

    Maryland Univ., College Park. Science Teaching Center.

    This multidisciplinary, self-contained curriculum unit focuses on the management of the Chesapeake Bay, a threatened and complex environmental system. Major unit goals include identifying and analyzing conflicting interests, issues, and public policies concerning the Bay, and determining their effects on people and the environment. The unit…

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

    USDA-ARS?s Scientific Manuscript database

    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 agricu...

  15. Decision Making/The Chesapeake Bay. An Interdisciplinary Environmental Education Curriculum Unit.

    ERIC Educational Resources Information Center

    Maryland Univ., College Park. Science Teaching Center.

    This multidisciplinary, self-contained curriculum unit focuses on the management of the Chesapeake Bay, a threatened and complex environmental system. Major unit goals include identifying and analyzing conflicting interests, issues, and public policies concerning the Bay, and determining their effects on people and the environment. The unit…

  16. Islands at bay: Rising seas, eroding islands, and waterbird habitat loss in Chesapeake Bay (USA)

    USGS Publications Warehouse

    Erwin, R.M.; Brinker, D.F.; Watts, B.D.; Costanzo, G.R.; Morton, D.D.

    2011-01-01

    Like many resources in the Chesapeake Bay region of the U. S., many waterbird nesting populations have suffered over the past three to four decades. In this study, historic information for the entire Bay and recent results from the Tangier Sound region were evaluated to illustrate patterns of island erosion and habitat loss for 19 breeding species of waterbirds. Aerial imagery and field data collected in the nesting season were the primary sources of data. From 1993/1994 to 2007/2008, a group of 15 islands in Tangier Sound, Virginia were reduced by 21% in area, as most of their small dunes and associated vegetation and forest cover were lost to increased washovers. Concurrently, nesting American black ducks (Anas rubripes) declined by 66%, wading birds (herons-egrets) by 51%, gulls by 72%, common terns (Sterna hirundo) by 96% and black skimmers (Rynchops niger) by about 70% in this complex. The declines noted at the larger Bay-wide scale suggest that this study area maybe symptomatic of a systemic limitation of nesting habitat for these species. The island losses noted in the Chesapeake have also been noted in other Atlantic U. S. coastal states. Stabilization and/or restoration of at least some of the rapidly eroding islands at key coastal areas are critical to help sustain waterbird communities. ?? 2010 US Government.

  17. Assessing benthic community condition in Chesapeake Bay: does the use of different benthic indices matter?

    PubMed

    Llansó, Roberto J; Vølstad, Jon H; Dauer, Daniel M; Dew, Jodi R

    2009-03-01

    Federal and state environmental agencies conduct several programs to characterize the environmental condition of Chesapeake Bay. These programs use different benthic indices and survey designs, and have produced assessments that differ in the estimate of the extent of benthic community degradation in Chesapeake Bay. Provided that the survey designs are unbiased, differences may exist in the ability of these indices to identify environmental degradation. In this study we compared the results of three indices calculated on the same data, and the assessments of two programs: the Chesapeake Bay Program and the Mid-Atlantic Integrated Assessment (MAIA). We examined the level of agreement of index results using site-based measures of agreement, evaluated sampling designs and statistical estimation methods, and tested for significant differences in assessments. Comparison of ratings of individual sites was done within separate categories of water and sediment quality to identify which indices summarize best pollution problems in Chesapeake Bay. The use of different benthic indices by these programs produced assessments that differed significantly in the estimate of degradation. A larger fraction of poor sites was classified as good by the Environmental Monitoring and Assessment Program's Virginian Province and MAIA benthic indices compared to the Chesapeake Bay benthic index of biotic integrity, although overall classification efficiencies were similar for all indices. Differences in survey design also contributed to differences in assessments. The relative difference between the indices remained the same when they were applied to an independent dataset, suggesting that the indices can be calibrated to produce consistent results.

  18. Development and application of econometric demand and supply models for selected Chesapeake Bay seafood products

    SciTech Connect

    Nieves, L.A.; Moe, R.J.

    1984-12-01

    Five models were developed to forecast future Chesapeake seafood product prices, harvest quantities, and resulting income. Annual econometric models are documented for oysters, hard and soft blue crabs, and hard and soft clams. To the degree that data permit, these models represent demand and supply at the retail, wholesale, and harvest levels. The resulting models have broad applications in environmental policy issues and regulatory analyses for the Chesapeake Bay. 37 references, 10 figures, 99 tables.

  19. HYPOXIA IN CHESAPEAKE BAY, 1950-2001: LONG-TERM CHANGE IN RELATION TO NUTRIENT LOADING AND RIVER FLOW

    EPA Science Inventory

    A 52-yr record of dissolved oxygen in Chesapeake Bay (1950 to 2001) and a record of nitrate (NO3-) loading by the Susquehanna River spanning a longer period (1903, 1945 to 2001) were assembled to describe the long-term pattern of hypoxia and anoxia in Chesapeake Bay an...

  20. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  1. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  2. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  3. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  4. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  5. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  6. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  7. 33 CFR 334.400 - Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Camp Pendleton, Virginia; naval restricted area. 334.400 Section 334.400... AND RESTRICTED AREA REGULATIONS § 334.400 Atlantic Ocean south of entrance to Chesapeake Bay off Camp...

  8. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  9. 33 CFR 334.380 - Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck, Virginia; naval firing range. 334.380 Section 334.380 Navigation and... RESTRICTED AREA REGULATIONS § 334.380 Atlantic Ocean south of entrance to Chesapeake Bay off Dam Neck...

  10. HYPOXIA IN CHESAPEAKE BAY, 1950-2001: LONG-TERM CHANGE IN RELATION TO NUTRIENT LOADING AND RIVER FLOW

    EPA Science Inventory

    A 52-yr record of dissolved oxygen in Chesapeake Bay (1950 to 2001) and a record of nitrate (NO3-) loading by the Susquehanna River spanning a longer period (1903, 1945 to 2001) were assembled to describe the long-term pattern of hypoxia and anoxia in Chesapeake Bay an...

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

    ERIC Educational Resources Information Center

    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…

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

    ERIC Educational Resources Information Center

    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…

  13. Revised method and outcomes for estimating soil phosphorus losses from agricultural land in the Chesapeake Bay watershed model

    USDA-ARS?s Scientific Manuscript database

    Current restoration efforts for the Chesapeake Bay watershed mandate a timeline for reducing the load of nutrients and sediment to receiving waters. The Chesapeake Bay Watershed Model (WSM) has been used for two decades to simulate hydrology and nutrient and sediment transport; however, spatial limi...

  14. Recent Trends in Suspended Sediment Load & Water Quality in the Upper Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Freeman, L. A.; Ackleson, S. G.

    2016-02-01

    The Chesapeake Bay spans several major cities on the US east coast and drains a large watershed (164,200 km2) to the Atlantic Ocean. Upstream deforestation and agriculture have led to a major decline in water quality (increased sediment and nutrient load) of the Bay over the past century. Sediment flux into the Chesapeake Bay is a natural process, but has become an environmental concern as land use changes have exacerbated natural suspended sediment loads and saturated the capacity of the estuary to filter and remove sediments. In situ measurements of suspended sediments and surface reflectance from the Potomac, Patapsco, and Severn River were used to develop algorithms that convert surface reflectance from Landsat (1-3, 4-5, 7, 8) imagery to suspended sediment concentration for the entire Chesapeake Bay. A unique time series of suspended sediment load in the Chesapeake Bay was compiled from Landsat imagery dating from 1977-2015. Particular focus is given to the upper Chesapeake Bay near Washington, DC and Baltimore, MD to understand urban effects. In particular, the Potomac, Patapsco, and Severn River are examined from both remote sensing and in situ measurements. Landsat imagery combined with in situ monitoring provides environmental scientists and resource managers with detailed trends in sediment distribution and concentration, a key measure of water quality. Trends of suspended sediment load in several rivers and the upper Chesapeake Bay will be presented, along with a discussion of suspended sediment algorithms for Landsat imagery. Advantages of Landsat 8 (improved signal-to-noise performance and more bands) versus previous sensors will be examined for suspended sediment applications.

  15. Variable climatic conditions dominate recent phytoplankton dynamics in Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Harding, Lawrence W., Jr.; Mallonee, Michael E.; Perry, Elgin S.; Miller, W. David; Adolf, Jason E.; Gallegos, Charles L.; Paerl, Hans W.

    2016-03-01

    Variable climatic conditions strongly influence phytoplankton dynamics in estuaries globally. Our study area is Chesapeake Bay, a highly productive ecosystem providing natural resources, transportation, and recreation for nearly 16 million people inhabiting a 165,000-km2 watershed. Since World War II, nutrient over-enrichment has led to multiple ecosystem impairments caused by increased phytoplankton biomass as chlorophyll-a (chl-a). Doubled nitrogen (N) loadings from 1945–1980 led to increased chl-a, reduced water clarity, and low dissolved oxygen (DO), while decreased N loadings from 1981–2012 suggest modest improvement. The recent 30+ years are characterized by high inter-annual variability of chl-a, coinciding with irregular dry and wet periods, complicating the detection of long-term trends. Here, we synthesize time-series data for historical and recent N loadings (TN, NO2 + NO3), chl-a, floral composition, and net primary productivity (NPP) to distinguish secular changes caused by nutrient over-enrichment from spatio-temporal variability imposed by climatic conditions. Wet years showed higher chl-a, higher diatom abundance, and increased NPP, while dry years showed lower chl-a, lower diatom abundance, and decreased NPP. Our findings support a conceptual model wherein variable climatic conditions dominate recent phytoplankton dynamics against a backdrop of nutrient over-enrichment, emphasizing the need to separate these effects to gauge progress toward improving water quality in estuaries.

  16. Geochemical factors affecting PAH distribution in Chesapeake Bay sediments

    SciTech Connect

    Mitra, S.; Dickhut, R.M.; Kimbrough, K.

    1995-12-31

    Sediment/pore water distribution coefficients (K{sub d}s) of selected polycyclic aromatic hydrocarbons (PAHs) were examined with depth at two sites in the Elizabeth River, a tributary of the Chesapeake Bay, Virginia. Areas of the Elizabeth River have been historically extensively contaminated with PAHs. Varying trends in distribution coefficients were observed both across the range of molecular weights of the PAHs and with depth in the sediment. Linear relations between log K{sub d} and octanol-water partition coefficient (log K{sub ow}) were observed deep in the cores but not near the surface of the sediments. This phenomena indicates that PAH sediment/porewater distributions are not at equilibrium near the sediment-water interface. Moreover, down-core K{sub d}s decreased and were, in most cases, inversely related with fraction organic carbon. These data indicate that dissolved organic carbon (DOC) may play a potentially significant role in mobilizing sediment-associated organic contaminants. The extent to which DOC and other geochemical parameters such as total lipid extract (TLE) and BET surface area control K{sub d}s of PAHs, is under further investigation.

  17. Variable climatic conditions dominate recent phytoplankton dynamics in Chesapeake Bay.

    PubMed

    Harding, Lawrence W; Mallonee, Michael E; Perry, Elgin S; Miller, W David; Adolf, Jason E; Gallegos, Charles L; Paerl, Hans W

    2016-03-30

    Variable climatic conditions strongly influence phytoplankton dynamics in estuaries globally. Our study area is Chesapeake Bay, a highly productive ecosystem providing natural resources, transportation, and recreation for nearly 16 million people inhabiting a 165,000-km(2) watershed. Since World War II, nutrient over-enrichment has led to multiple ecosystem impairments caused by increased phytoplankton biomass as chlorophyll-a (chl-a). Doubled nitrogen (N) loadings from 1945-1980 led to increased chl-a, reduced water clarity, and low dissolved oxygen (DO), while decreased N loadings from 1981-2012 suggest modest improvement. The recent 30+ years are characterized by high inter-annual variability of chl-a, coinciding with irregular dry and wet periods, complicating the detection of long-term trends. Here, we synthesize time-series data for historical and recent N loadings (TN, NO2 + NO3), chl-a, floral composition, and net primary productivity (NPP) to distinguish secular changes caused by nutrient over-enrichment from spatio-temporal variability imposed by climatic conditions. Wet years showed higher chl-a, higher diatom abundance, and increased NPP, while dry years showed lower chl-a, lower diatom abundance, and decreased NPP. Our findings support a conceptual model wherein variable climatic conditions dominate recent phytoplankton dynamics against a backdrop of nutrient over-enrichment, emphasizing the need to separate these effects to gauge progress toward improving water quality in estuaries.

  18. Variable climatic conditions dominate recent phytoplankton dynamics in Chesapeake Bay

    PubMed Central

    Harding, Jr., Lawrence W.; Mallonee, Michael E.; Perry, Elgin S.; Miller, W. David; Adolf, Jason E.; Gallegos, Charles L.; Paerl, Hans W.

    2016-01-01

    Variable climatic conditions strongly influence phytoplankton dynamics in estuaries globally. Our study area is Chesapeake Bay, a highly productive ecosystem providing natural resources, transportation, and recreation for nearly 16 million people inhabiting a 165,000-km2 watershed. Since World War II, nutrient over-enrichment has led to multiple ecosystem impairments caused by increased phytoplankton biomass as chlorophyll-a (chl-a). Doubled nitrogen (N) loadings from 1945–1980 led to increased chl-a, reduced water clarity, and low dissolved oxygen (DO), while decreased N loadings from 1981–2012 suggest modest improvement. The recent 30+ years are characterized by high inter-annual variability of chl-a, coinciding with irregular dry and wet periods, complicating the detection of long-term trends. Here, we synthesize time-series data for historical and recent N loadings (TN, NO2 + NO3), chl-a, floral composition, and net primary productivity (NPP) to distinguish secular changes caused by nutrient over-enrichment from spatio-temporal variability imposed by climatic conditions. Wet years showed higher chl-a, higher diatom abundance, and increased NPP, while dry years showed lower chl-a, lower diatom abundance, and decreased NPP. Our findings support a conceptual model wherein variable climatic conditions dominate recent phytoplankton dynamics against a backdrop of nutrient over-enrichment, emphasizing the need to separate these effects to gauge progress toward improving water quality in estuaries. PMID:27026279

  19. Controls on nitrogen loss processes in Chesapeake Bay sediments.

    PubMed

    Babbin, Andrew R; Ward, Bess B

    2013-05-07

    The flux of fixed nitrogen into the marine environment is increasing as a direct result of anthropogenic nitrogen loading, but the controls on the mechanisms responsible for the removal of this increased supply are not well constrained. The fate of fixed nitrogen via mineralization and nitrogen loss processes was investigated by simulating a settling event of organic matter (OM) in mesocosms containing Chesapeake Bay sediments. Microorganisms rapidly transformed the OM during the course of a seven week incubation ultimately leading to nitrogen loss via denitrification and anaerobic ammonium oxidation (anammox). The microbial community responded quickly to the OM amendment suggesting that estuarine sediments can buffer the natural system against sudden injections of organic material. Two different levels of organic matter amendment resulted in different magnitudes of ammonium and nitrite accumulation during the incubation, but both treatments exhibited the same overall sequence of dissolved inorganic nitrogen (DIN) accumulation and removal. An inverse least-squares analysis coupled to a Michaelis-Menten prognostic model was conducted to estimate rates of nitrogen transformations from the measured DIN concentrations. Whereas the rates were higher at higher OM, the percentage of nitrogen lost via anammox was constant at 44.3 ± 0.3%. The stoichiometry of organic matter and the allochthonous supply of ammonium determined the relative contribution of anammox and denitrification to overall nitrogen loss. Further, in situ thermodynamics based on measured concentrations suggested that the energy favorability of denitrification and anammox plays a role in determining the timing of these processes as OM remineralization progresses.

  20. Novel psychrotolerant picocyanobacteria isolated from Chesapeake Bay in the winter.

    PubMed

    Xu, Yongle; Jiao, Nianzhi; Chen, Feng

    2015-08-01

    Picocyanobacteria are major primary producers in the ocean, especially in the tropical or subtropical oceans or during warm seasons. Many "warm" picocyanobacterial species have been isolated and characterized. However, picocyanobacteria in cold environments or cold seasons are much less studied. In general, little is known about the taxonomy and ecophysiology of picocyanobacteria living in the winter. In this study, 17 strains of picocyanobacteria were isolated from Chesapeake Bay, a temperate estuarine ecosystem, during the winter months. These winter isolates belong to five distinct phylogenetic lineages, and are distinct from the picocyanobacteria previously isolated from the warm seasons. The vast majority of the winter isolates were closely related to picocyanobacteria isolated from other cold environments like Arctic or subalpine waters. The winter picocyanobacterial isolates were able to maintain slow growth or prolonged dormancy at 4°C. Interestingly, the phycoerythrin-rich strains outperformed the phycocyanin-rich strains at cold temperature. In addition, winter picocyanobacteria changed their morphology when cultivated at 4°C. The close phylogenetic relationship between the winter picocyanobacteria and the picocyanobacteria living in high latitude cold regions indicates that low temperature locations select specific ecotypes of picocyanobacteria. © 2015 Phycological Society of America.

  1. Food habits and distribution of wintering canvasbacks, Aythya valisineria, on Chesapeake Bay

    USGS Publications Warehouse

    Perry, M.C.; Uhler, F.M.

    1988-01-01

    Baltic clams (Macoma balthica) were the predominant food items of 323 canvasbacks (Aythya valisineria) collected throughout Chesapeake Bay during 1970-1979. Natural vegetation constituted 4% of the food volume. Widgeongrass (Ruppia maritima) and redhead grass (Potamogeton perfoliatus) constituted the greatest percent volume and frequency of occurrence among the plant species, whereas wild celery (Vallisneria americana) constituted only a trace of the food volume. These results contrast with historical records of food habits of canvasbacks in Chesapeake Bay. Canvasback population estimates during the 1970?s were examined to detect annual and seasonal changes in distribution. Linear regression analyses of winter canvasback populations in the bay showed a significant decline in the upper-bay and middle-bay populations, but no significant changes in the lower-bay and Potomac River populations. The changes in winter distribution and abundance of the canvasback appear related to changes in natural food availability, which is the result of altered environmental conditions.

  2. Robust Decision Making to Support Improved Water Quality Planning: a Case Study in the Chesapeake Bay Watershed

    NASA Astrophysics Data System (ADS)

    Fischbach, J. R.; Lempert, R. J.; Molina-Perez, E.

    2016-12-01

    The U.S. Environmental Protection Agency (USEPA), together with state and local partners, develops watershed implementation plans designed to meet water quality standards. Uncertainty regarding the impacts of climate change, future land use, the effectiveness of water quality best management practices (BMPs), and other drivers may make it difficult for these implementation plans to meet water quality goals. In this effort, we explored how Robust Decision Making (RDM) methods could help USEPA and its partners develop implementation plans that are more robust to such uncertainty. The pilot study focuses on one part of the Chesapeake Bay watershed, the Patuxent River, which is 2,479 km2 in area, highly urbanized, and has a rapidly growing population. We simulated the contribution of stormwater contaminants from the Patuxent to the overall Total Maximum Daily Load (TMDL) for the Chesapeake Bay under multiple scenarios. Contaminants considered included nitrogen, phosphorus, and sediment loads. The assessment included a large set of scenario simulations using the USEPA Chesapeake Bay Program's Phase V watershed model. Uncertainties represented in the analysis include 12 land use scenarios with different population projections and development patterns, 18 climate change scenarios (based on 6 general circulation models and 3 emissions pathways), several future time periods, and alternative assumptions about BMP performance standards and efficiencies associated with different suites of stormwater BMPs. Finally, we developed cost estimates for each of the performance standards and compared cost to TMDL performance as a key tradeoff for future water quality management decisions. This pilot study is intended to support the Chesapeake Bay Program in providing climate-related decision support for water quality management, and more generally to help USEPA assess the effectiveness of RDM to support water quality management.

  3. Nutrient reduction policies and management strategies of the Chesapeake Bay water quality restoration program.

    PubMed

    Randall, C W

    2001-01-01

    The Chesapeake Bay Program is a unique, regional, federal-state-local partnership established in 1983 by a formal Agreement between six signatories, the states of Maryland, Pennsylvania and Virginia, the District of Columbia, the US EPA, and the Chesapeake Bay Commission, to protect and restore the Bay's ecosystem. The system of governance adopted provides for dynamic interaction between the signatories, and provides for input from the interested citizens, the local governments, and the scientific and technical community. The Agreement is periodically reviewed, amended and added to by new agreements, with the most recent being the 2000 Agreement, referred to as "Chesapeake 2000: A Watershed Partnership". The new agreement, signed 28 June 2000, sets numeric goals to be accomplished during the next ten years, and includes land use policies and restrictions.

  4. Black Ducks and Their Chesapeake Bay Habitats: Proceedings of a Symposium

    USGS Publications Warehouse

    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.

  5. An assessment of benthic condition in several small watersheds of the Chesapeake Bay, USA.

    PubMed

    Leight, Andrew K; Slacum, Ward H; Wirth, Ed F; Fulton, Mike H

    2011-05-01

    We examined benthic condition in three small watersheds in the Chesapeake Bay. Characterization of benthic condition was based on the combined measurements of benthic fauna, sediment toxicity, and sediment contaminant loads. Significant differences between watersheds were detected for sediment contaminant concentrations and water quality. The intensity of benthic impairment was greatest in the river surrounded by the most developed watershed. Spatial patterns of benthic condition were detected within all three watersheds. In contrast to current, intense focus on nutrient pollution in the Chesapeake Bay, qualitative comparison of our findings to land-use patterns supports findings of other studies that suggest benthic condition in tributaries of the Chesapeake Bay may more closely relate to urbanization than agricultural land uses.

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

    USGS Publications Warehouse

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

    2013-01-01

    High salinity groundwater more than 1000 metres deep in the Atlantic Coastal Plain of the United States has been documented in several locations1,2, most recently within the 35 million-year-old Chesapeake Bay impact crater3,4,5. Suggestions for the origin of increased salinity in the crater have included evaporite dissolution6, osmosis6, and evaporation from heating7 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) seawater. We find that the seawater is likely 100-145 million years old and that it has an average salinity of about 70 per mil, which is twice that of modern seawater and consistent with the nearly closed ECNA basin8. Previous evidence for temperature and salinity levels of ancient oceans have been estimated indirectly from geochemical, isotopic and paleontological analyses of solid materials in deep sediment cores. In contrast, our study identifies ancient seawater in situ and provides a direct estimate of its age and salinity. Moreover, we suggest that it is likely that remnants of ECNA seawater persist in deep sediments at many locations along the Atlantic margin.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  9. Susceptibility of east coast estuaries to nutrient discharges: Passamaquoddy Bay to Chesapeake Bay. Summary report

    SciTech Connect

    Quinn, H.; Tolson, J.P.; Klein, C.J.; Orlando, S.P.; Alexander, C.

    1989-06-01

    This is the third report in a series being developed to assist the US EPA implement its Near Coastal Waters and National Estuary Programs. It summarizes estimates of the relative susceptibility and status of 17 estuaries on the East Coast from Maine through Virginia, with respect to nutrient-related pollution. The information is intended to increase understanding of coastal environmental problems and to serve as a screening tool for coastal resource decision-making. A one-page summary is included in the report for each of the 17 estuaries in the East Coast region from Passamaquoddy Bay through Chesapeake Bay. Each summary contains data on significant physical and hydrologic features, estimations of nutrient loading, pollution susceptibility, and nutrient concentrations, along with a narrative to assist the reader in interpreting the data.

  10. Population Dynamics of Chesapeake Bay Virioplankton: Total-Community Analysis by Pulsed-Field Gel Electrophoresis†

    PubMed Central

    Wommack, K. Eric; Ravel, Jacques; Hill, Russell T.; Chun, Jongsik; Colwell, Rita R.

    1999-01-01

    Recognition of viruses as the most abundant component of aquatic microbial communities has stimulated investigations of the impact of viruses on bacterio- and phytoplankton host communities. From results of field studies to date, it is concluded that in most aquatic environments, a reduction in the number of bacteria on a daily basis is caused by viral infection. However, the modest amount of in situ virus-mediated mortality may be less significant than viral infection serving to maintain clonal diversity in the host communities directly, through gene transmission (i.e., transduction), and indirectly, by elimination of numerically dominant host species. If the latter mechanism for controlling community diversity prevails, then the overall structure of aquatic viral communities would be expected to change as well over short seasonal and spatial scales. To determine whether this occurs, pulsed-field gel electrophoresis (PFGE) was used to monitor the population dynamics of Chesapeake Bay virioplankton for an annual cycle (1 year). Virioplankton in water samples collected at six stations along a transect running the length of the bay were concentrated 100-fold by ultrafiltration. Viruses were further concentrated by ultracentrifugation, and the concentrated samples were embedded in agarose. PFGE analysis of virus DNA in the agarose plugs yielded several distinct bands, ranging from 50 to 300 kb. Principal-component and cluster analyses of the virus PFGE fingerprints indicated that changes in virioplankton community structure were correlated with time, geographical location, and extent of water column stratification. From the results of this study, it is concluded that, based on the dynamic nature of the Chesapeake Bay virioplankton community structure, the clonal diversity of bacterio- and phytoplankton host communities is an important component of the virus community. PMID:9872784

  11. Characterization of the Chesapeake Bay: A systematic analysis of toxic trace elements

    SciTech Connect

    Kingston, H.M.; Greeberg, R.R.; Beary, E.S.; Hardas, B.R.; Moody, J.R.

    1983-11-01

    As part of a multidisciplinary study of the Chesapeake Bay, the National Bureau of Standards (NBS) was asked to develop the techniques and procedures necessary to measure the trace and toxic element concentrations within the water column through the entire length of the Chesapeake Bay. The Inorganic Analytical Research Division of the Center for Analytical Chemistry at NBS has completed the analysis for selected elements (Cd, Ce, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sc, Sn, Th, U, and Zn), including some elements at concentrations consistently below one picogram per milliter (part per trillion).

  12. Reproductive health of yellow perch, Perca flavescens, in Chesapeake Bay Tributaries

    USGS Publications Warehouse

    Blazer, Vicki; Pinkney, A.E.; Uphoff, James H.

    2013-01-01

    Yellow perch live in creeks, rivers, ponds, lakes, and estuaries across the central and eastern United States and Canada. In Chesapeake Bay, they tolerate salinities up to one-third that of seawater. The adults reside in the brackish waters of the bay’s tributaries and migrate upstream to spawn. Yellow perch are eagerly sought by recreational fishermen for their excellent taste and, because their late winter spawning runs are the earliest of the year, they are regarded as a harbinger of spring. Yellow perch also support a small but valuable, tightly regulated commercial fishery in the part of Chesapeake Bay that lies in Maryland.

  13. Historical presence (1975-1985) of mycobacteriosis in Chesapeake Bay striped bass Morone saxatilis.

    PubMed

    Jacobs, John M; Howard, Dorothy W; Rhodes, Matt R; Newman, Martin W; May, Eric B; Harrell, Reginal M

    2009-07-23

    A retrospective analysis of archived tissue blocks has revealed that mycobacteriosis was apparent in Chesapeake Bay striped bass as early as 1984. Of 37 cases available from the years 1975 to 1985, 2 fish were found positive based on histopathology and genus-specific PCR. Multi-gene sequencing places the bacteria from the 2 positive cases (1984 and 1985) within the Mycobacterium tuberculosis clade with closest resemblance to the recently described fish pathogen M. pseudoshottsii. Our data confirms that mycobacteriosis is not a new disease of Chesapeake Bay striped bass and underscores the value of archived tissues in epidemiological examinations.

  14. Ancient channels of the Susquehanna River beneath Chesapeake Bay and the Delmarva Peninsula

    USGS Publications Warehouse

    Colman, Steven M.; Halka, J.P.; Hobbs, C. H.; Mixon, R.B.; Foster, D.S.

    1990-01-01

    The trunk channels of each system are 2 to 4 km wide and are incised 30 to 50 m into underlying strata; they have irregular longitudinal profiles and very low gradients within the Chesapeake Bay area. The youngest paleochannel is clearly of late Wisconsinan age, about 18 ka, and the intermediate one appears to be late Illinoian in age, or about 150 ka. The age of the oldest is in the range of about 200 to 400 ka. The three paleochannel systems imply a dynamic coastal-plain environment and at least two previous generations of the Chesapeake Bay. -from Authors

  15. Chesapeake Bay coordinated split sample program annual report, 1990-1991: Analytical methods and quality assurance workgroup of the Chesapeake Bay program monitoring subcommittee

    SciTech Connect

    Not Available

    1991-01-01

    The Chesapeake Bay Program is a federal-state partnership with a goal of restoring the Chesapeake Bay. Its ambient water quality monitoring programs, started in 1984, sample over 150 monitoring stations once or twice a month a month. Due to the size of the Bay watershed (64,000 square miles) and the cooperative nature of the CBP, these monitoring programs involve 10 different analytical laboratories. The Chesapeake Bay Coordinated Split Sample Program (CSSP), initialed in 1988, assesses the comparability of the water quality results from these laboratories. The report summarizes CSSP results for 1990 and 1991, its second and third full years of operation. The CSSP has two main objectives: identifying parameters with low inter-organization agreement, and estimating measurement system variability. The identification of parmeters with low agreement is used as part of the overall Quality Assurance program. Laboratory and program personnel use the information to investigate possible causes of the differences, and take action to increase agreement if possible. Later CSSP results will document any improvements in inter-organization agreement. The variability estimates are most useful to data analysts and modelers who need confidence estimates for monitoring data.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26657975

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

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

    2015-12-10

    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.

  19. Chesapeake Bay regions of concern: Geographical targeting protocol for remediation, reduction, prevention and assessment actions

    SciTech Connect

    Batiuk, R.A.

    1994-12-31

    As a result of a two year reevaluation of a Basinwide Toxics Reduction Strategy, the Chesapeake Bay Program identified the need to more effectively direct reduction and prevention actions toward regional areas with known toxic problems as well as areas where significant potential exists for toxic impacts on living resources and habitats. Building upon the geographical targeting efforts in the Great Lakes and Puget Sound, a protocol was established for identifying and categorizing areas ranging from known toxic problems to areas with low probability for adverse effects to insufficient data. The identification protocol is based on a series of criteria which include evaluation of sediment contamination concentrations and ambient sediment toxicity. The process for development and application of the Regions of Concern protocol along with a focus on the sediment assessment criteria and how they influenced the over-all categorization of regions will be presented.

  20. Particle-borne radionuclides as tracers for sediment in the Susquehanna River and Chesapeake Bay

    USGS Publications Warehouse

    Donoghue, J.F.; Bricker, O.P.; Olsen, C.R.

    1989-01-01

    The Chesapeake Bay receives nearly 1 000 000 tonnes of sediment annually from its major tributary, the Susquehanna River. The pattern of deposition of this sediment affects the lifetime of the estuarine resource and the fate of any sediment-borne contaminants. Previous estimates of the extent to which Susquehanna River sediment is transported down the Chesapeake have differed considerably. By use of reactor-generated radionuclides adsorbed on the river sediment, a sediment budget has been compiled for the upper Chesapeake Bay and the reservoirs on the lower Susquehanna. Reservoirs impound nearly 1 400 000 tonnes of sediment annually behind the power dams on the lower Susquehanna River. Without the dams, sediment delivery to the upper bay would more than double. The uppermost Chesapeake Bay, within and above the turbidity maximum, retains virtually all of the fluvial sediment delivered to it. The result is an annual sedimentation rate of approximately 3 mm yr-1 in the upper bay, an infilling rate that is nearly equal to the regional rate of sea level rise. ?? 1989.

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

    USGS Publications Warehouse

    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.

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

    USGS Publications Warehouse

    Batiuk, Richard A.; Breitburg, Denise L.; Diaz, Robert J.; Cronin, Thomas M.; Secor, David H.; Thursby, Glen

    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.

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

    USGS Publications Warehouse

    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

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

    USGS Publications Warehouse

    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.

  5. Apparent genetic homogeneity of spawning striped bass in the upper Chesapeak Bay

    SciTech Connect

    Sidell, B.D.; Otto, R.G.; Powers, D.A. Karweit, M.; Smith, J.

    1980-01-01

    The possible existence of genetically distinct populations of spawning striped bass (Morone saxatilis) in the river systems of the upper Chesapeake Bay was investigated by a biochemical genetic approach. Samples of blood and liver from adult fish were obtained during the 1976 spawning runs from the Rappanhannock (Virginia), Potomac, Choptank, Sassafras, Bohemia, and Elk rivers (Maryland), and Maryland waters of the Chesapeake and Delaware Canal. Samples were analyzed for frequency of occurrence of a polymorphic liver enzyme, glycerol-3-phosphate dehydrogenase, and variable serum proteins which were not correlated with age or sex. Multivariate and Bayesian analyses of these data indicate apparent genetic homogeneity of spawning bass within the upper Chesapeake Bay. If natal stream homing occurs, a sufficient number of wanderers may provide significant gene flow among river systems. The results suggest that long-term management of the fishery need not be totally on the basis of separate river units.

  6. Developing Oxidized Nitrogen Atmospheric Deposition Source Attribution from CMAQ for Air-Water Trading for Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Dennis, R. L.; Napelenok, S. L.; Linker, L. C.; Dudek, M.

    2012-12-01

    Estuaries are adversely impacted by excess reactive nitrogen, Nr, from many point and nonpoint sources, including atmospheric deposition to the watershed and the estuary itself as a nonpoint source. For effective mitigation, trading among sources of Nr is being considered. The Chesapeake Bay Program is working to bring air into its trading scheme, which requires some special air computations. Airsheds are much larger than watersheds; thus, wide-spread or national emissions controls are put in place to achieve major reductions in atmospheric Nr deposition. The tributary nitrogen load reductions allocated to the states to meet the TMDL target for Chesapeake Bay are large and not easy to attain via controls on water point and nonpoint sources. It would help the TMDL process to take advantage of air emissions reductions that would occur with State Implementation Plans that go beyond the national air rules put in place to help meet national ambient air quality standards. There are still incremental benefits from these local or state-level controls on atmospheric emissions. The additional air deposition reductions could then be used to offset water quality controls (air-water trading). What is needed is a source to receptor transfer function that connects air emissions from a state to deposition to a tributary. There is a special source attribution version of the Community Multiscale Air Quality model, CMAQ, (termed DDM-3D) that can estimate the fraction of deposition contributed by labeled emissions (labeled by source or region) to the total deposition across space. We use the CMAQ DDM-3D to estimate simplified state-level delta-emissions to delta-atmospheric-deposition transfer coefficients for each major emission source sector within a state, since local air regulations are promulgated at the state level. The CMAQ 4.7.1 calculations are performed at a 12 km grid size over the airshed domain covering Chesapeake Bay for 2020 CAIR emissions. For results, we first present

  7. Chesapeake Bay mainstem monitoring program statistical and analytical support contract: final report, Volume 1

    SciTech Connect

    Not Available

    1987-09-01

    The primary focus of this contract was the development of a statistical analysis framework for detection of trends in Chesapeake Bay water quality attributable to pollution-control-management actions. The report found that, while there are aspects of the main Bay water-quality monitoring program that can be improved, the overall approach of the program is sound and will provide the empirical information needed to characterize and detect trends in Chesapeake Bay water quality and to evaluate the effectiveness of management actions. Continuation of this coordinated monitoring effort provides the best opportunity for generation of rigorous statements concerning the State-of-the-Bay and for the development of an ecologically sound water-quality management strategy.

  8. Chesapeake bay mainstem monitoring program statistical and analytical support contract: final report, volume 2

    SciTech Connect

    Not Available

    1987-09-01

    The primary focus of this contract was the development of a statistical analysis framework for detection of trends in Chesapeake Bay water quality attributable to pollution-control-management actions. The report found that, while there are aspects of the main Bay water-quality monitoring program that can be improved, the overall approach of the program is sound and will provide the empirical information needed to characterize and detect trends in Chesapeake Bay water quality and to evaluate the effectiveness of management actions. Continuation of this coordinated monitoring effort provides the best opportunity for generation of rigorous statements concerning the State-of-the-Bay and for the development of an ecologically sound water-quality management strategy.

  9. Indicators of nitrate export from forested watersheds of the Chesapeake Bay region

    Treesearch

    Karl W. J. Williard

    1997-01-01

    Soil net nitrogen mineralization and nitrification rates were studied on nine relatively undisturbed, forested watersheds in an effort to explain the large variations in nitrate export in streamflow within the Chesapeake Bay region. The primary hypothesis tested was that nitrate export from the watersheds was positively associated with rates of net soil nitrogen...

  10. Nitrogen-fixing phylotypes of Chesapeake Bay and Neuse River estuary sediments.

    PubMed

    Burns, J A; Zehr, J P; Capone, D G

    2002-11-01

    Sediments often exhibit low rates of nitrogen fixation, despite the presence of elevated concentrations of inorganic nitrogen. The organisms that potentially fix nitrogen in sediments have not previously been identified. Amplification of nifH genes with degenerate primers was used to assess the diversity of diazotrophs in two distinct sediment systems, anoxic muds of Chesapeake Bay and shallow surficial sediments of the Neuse River. Phylogenetic analysis revealed that sequences obtained from mid-Chesapeake Bay, which receive high organic loading and are highly reducing, clustered closely with each other and with known anaerobic microorganisms, suggesting a low abundance of aerobic or facultative diazotrophs in these sediments. Sulfate reduction dominates in the surface, but methanogenesis becomes more important with depth. A thin (<1 cm) oxidized layer is present only in the spring. No archaeal nifH sequences were obtained from Chesapeake Bay. Sequences of nifH amplified from surficial sediments of the Neuse River were distant from Chesapeake Bay sequences and included nif phylotypes related to sequences previously reported from marine mats and the Spartina rhizosphere. Differences in environmental site characteristics appear to select for different types of sediment diazotrophs, which is reflected in the phylogenetic composition of amplified nifH sequences.

  11. Biology and Identification of Rays in the Chesapeake Bay. Sea Grant Program. Educational Series Number 20.

    ERIC Educational Resources Information Center

    Smith, Joseph W.; Merriner, J. V.

    This booklet provides a brief discussion of the anatomy and biology of rays in the Chesapeake Bay and a key to their identification. Descriptions of seven types of rays are also provided (with accompanying illustrations). These include electric rays, stingrays, butterfly rays, eagle rays, cownose rays, and manta rays. (JN)

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

    DTIC Science & Technology

    1980-08-01

    on methodology development and establishment of a baseline for determination of freshwater inflow-induced change. Physical and chemical information...III. OVERVIEW OF CHESAPEAKE BAY LITERATURE. . . . . . . . . . o35 A. Physical Aspects . . . *0 *0**PSS .35 1. Circulation and Salinity...145 . B. Definition of Ecological Baselines. . . . . . . . 149 1. Physical Base Year

  13. Cultural eutrophication in the Choptank and Patuxent estuaries of Chesapeake Bay

    EPA Science Inventory

    The Choptank and Patuxent tributaries of Chesapeake Bay have become eutrophic over the last 50–100 years. Systematic monitoring of nutrient inputs began in ;1970, and there have been 2–5-fold increases in nitrogen (N) and phosphorus (P) inputs during 1970–2004 due to sewage disch...

  14. CULTURAL EUTROPHICATION IN THE CHOPTANK AND PATUXENT ESTUARIES OF CHESAPEAKE BAY

    EPA Science Inventory

    The Choptank and Patuxent tributaries of Chesapeake Bay have become eutrophic over the last 50-100 years. Systematic monitoring of nutrient inputs began in ~1970, and there have been 2-5-fold increases in nitrogen (N) and phosphorus (P) inputs during 1970-2004 due to sewage disch...

  15. CLIMATE CHANGE AND EUTROPHICATION RESPONSES IN THE POTOMAC ESTUARY AND CHESAPEAKE BAY

    EPA Science Inventory

    Our analysis of tree ring and sediment core data indicates that climate variability in the 1900s had different consequences in the Potomac Estuary and Chesapeake Bay than in the previous two centuries as a result of anthropogenic activity affecting nutrient loadings in associated...

  16. 76 FR 12356 - A Method To Assess Climate-Relevant Decisions: Application in the Chesapeake Bay

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-07

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY A Method To Assess Climate-Relevant Decisions: Application in the Chesapeake Bay AGENCY... external peer review meeting of the draft document titled, ``A Method to Assess Climate-Relevant Decisions...

  17. CLIMATE CHANGE AND EUTROPHICATION RESPONSES IN THE POTOMAC ESTUARY AND CHESAPEAKE BAY

    EPA Science Inventory

    Our analysis of tree ring and sediment core data indicates that climate variability in the 1900s had different consequences in the Potomac Estuary and Chesapeake Bay than in the previous two centuries as a result of anthropogenic activity affecting nutrient loadings in associated...

  18. Cryptosporidium parvum in oysters from commercial harvesting sites in the Chesapeake Bay.

    PubMed

    Fayer, R; Lewis, E J; Trout, J M; Graczyk, T K; Jenkins, M C; Higgins, J; Xiao, L; Lal, A A

    1999-01-01

    Oocysts of Cryptosporidium parvum, a zoonotic waterborne pathogen, can be removed by bivalve molluscs from contaminated water and retained on gills and in hemolymph. We identified oocysts of C. parvum in oysters from seven sites in the Chesapeake Bay area. These findings document the presence of C. parvum infectious for humans in oysters intended for human consumption.

  19. Characteristics of total suspended matter and associated hydrocarbon concentration adjacent to the Chesapeake Bay entrance

    NASA Technical Reports Server (NTRS)

    Oertel, G. F.; Wade, T. L.

    1981-01-01

    Methodologies used to determine concentrations of hydrocarbons and associated suspended particulates at stations in and adjacent to the entrance to the Chesapeake Bay are described and the results are presented. Passive and active remote sensing data were acquired in conjunction with sea truth data collection.

  20. Suspended particulate matter in the Chesapeake Bay entrance and adjacent shelf waters

    NASA Technical Reports Server (NTRS)

    Gingerich, K. J.; Oertel, G. F.

    1981-01-01

    Approximately 400 samples were collected from the mouth of the Chesapeake Bay for various analyses, including 138 for suspended solids. Characteristics of suspended solids that were analyzed included: total suspended matter; total suspended inorganics, total suspended organics; percent organics; particle size distribution; and presence or absence of 11 of the most prominent particle types.

  1. Predicting thermal regimes of stream networks across the Chesapeake Bay Watershed: Natural and anthropogenic influences

    EPA Science Inventory

    Thermal regimes are a critical factor in models predicting joint effects of watershed management activities and climate change on fish habitat suitability. We have compiled a database of lotic temperature time series across the Chesapeake Bay Watershed (725 station-year combinat...

  2. Specific responsible environmental behavior among boaters on the Chesapeake Bay: a predictive model part II

    Treesearch

    Stuart P. Cottrell; Alan R. Graefe

    1995-01-01

    This paper examines predictors of boater behavior in a specific behavior situation, namely the percentage of raw sewage discharged from recreational vessels in a sanitation pumpout facility on the Chesapeake Bay. Results of a multiple regression analysis show knowledge predicts behavior in specific issue situations. In addition, the more specific the...

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

    EPA Pesticide Factsheets

    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.

  4. EPA Interim Evaluation of 2014-2015 Milestone Progress in the Chesapeake Bay Watershed

    EPA Pesticide Factsheets

    This page provides the EPA interim evaluations of the 2014-2015 milestones for the Chesapeake Bay TMDL. These interim assessments provide a mid-point check on the progress made on the 2014-2015 milestones, recognizing the achievements made in 2014.

  5. 76 FR 38300 - Safety Zone; Shore Thing and Independence Day Fireworks, Chesapeake Bay, Norfolk, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-30

    ... is establishing a temporary safety zone on the Chesapeake Bay in the vicinity of Ocean View Beach... necessary to provide for the safety of life on navigable waters during the Shore Thing and Independence Day... for immediate action, the restriction of vessel traffic is necessary to protect life, property and...

  6. Chesapeake Bay Riparian Handbook: A Guide for Establishing and Maintaining Riparian Forest Buffers

    Treesearch

    Roxane Palone; Albert Todd

    1998-01-01

    The Purpose of This Handbook Riparian forest buffers have been identified as avaluable nutrient reduction tool when used inconjunction with other conservation practices. For this reason, the Chesapeake Bay Programhas targeted riparian forests as a key habitat for restoration. The purpose of this handbook is toprovide professional land managers and plan-ners with the...

  7. Cross-frontal transport and distribution of ichthyoplankton associated with Chesapeake Bay plume dynamics

    NASA Astrophysics Data System (ADS)

    Reiss, Christian S.; McConaugha, John R.

    1999-02-01

    Cross-frontal transport associated with upwelling conditions was responsible for modifying ichthyoplankton distributions across the inner continental shelf waters off the Chesapeake Bay during late August 1988. Two ichthyoplankton assemblages characteristic of the Chesapeake Bay plume and inner-continental shelf waters were defined using multivariate analysis. Members of the plume assemblage ( Anchoa spp., Menticirrhus spp., and Micropogonias undulatus) were not retained within the Chesapeake Bay plume, but were instead advected 60 km onto the shelf within a low-salinity water mass. A second assemblage, dominated by several shelf-spawned taxa including Etropus microstomus, Prionotus spp. and Centropristis striata was distributed across the shelf. Atlantic croaker, M. undulatus, previously thought to be shelf-spawned exhibited a length-frequency distribution that increased from inshore to offshore, and paralleled that of Anchoa spp. This cross-shelf distribution, and the abundance of small (<3.5 mm), pre-flexion larvae inshore suggests that M. undulatus spawned near the plume front and were subsequently transported offshore with the plume assemblage. A mechanism for rapid cross-frontal transport is described. These findings suggest that the transport and recruitment patterns previously described for this taxon in Chesapeake Bay need to be re-examined. Larval survival and recruitment success of shelf-spawned estuarine species, like M. undulatus, are likely tied to oceanographic conditions on the inner shelf related to upwelling and downwelling conditions and plume dynamics, rather than to simple, wind-driven recruitment mechanisms.

  8. 33 CFR 334.140 - Chesapeake Bay; U.S. Army Proving Ground Reservation, Aberdeen, Md.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Point; thence southeasterly along the low water mark on the shore of Chesapeake Bay to and across the north entrance of Spesutie Narrows to and thence along the low water mark on the north shore of Spesutie... approximately 1,400 yards; thence following a line parallel with and 1,000 yards from the low water mark on...

  9. 33 CFR 334.140 - Chesapeake Bay; U.S. Army Proving Ground Reservation, Aberdeen, Md.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... easterly shore of Spesutie Island to a point 1,000 yards due southeast of Sandy Point; thence approximately... Point; thence southeasterly along the low water mark on the shore of Chesapeake Bay to and across the north entrance of Spesutie Narrows to and thence along the low water mark on the north shore of Spesutie...

  10. CULTURAL EUTROPHICATION IN THE CHOPTANK AND PATUXENT ESTUARIES OF CHESAPEAKE BAY

    EPA Science Inventory

    The Choptank and Patuxent tributaries of Chesapeake Bay have become eutrophic over the last 50-100 years. Systematic monitoring of nutrient inputs began in ~1970, and there have been 2-5-fold increases in nitrogen (N) and phosphorus (P) inputs during 1970-2004 due to sewage disch...

  11. Cultural eutrophication in the Choptank and Patuxent estuaries of Chesapeake Bay

    EPA Science Inventory

    The Choptank and Patuxent tributaries of Chesapeake Bay have become eutrophic over the last 50–100 years. Systematic monitoring of nutrient inputs began in ;1970, and there have been 2–5-fold increases in nitrogen (N) and phosphorus (P) inputs during 1970–2004 due to sewage disch...

  12. Effects of power-plant generated contaminants on trophic relationships in Chesapeake Bay

    SciTech Connect

    Sanders, J.G.; Riedel, G.F.; Connell, D.B.

    1997-09-01

    This project tested the hypothesis that shifts in phytoplankton species composition that occur when Chesapeake Bay phytoplankton communities are chronically exposed to low levels of toxic trace metals can lead to altered (reduced) flow of carbon to higher trophic levels of the conventional food web and increased movement of carbon through microbial food chains and degradation pathways.

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

    EPA Science Inventory

    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 ...

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

    ERIC Educational Resources Information Center

    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…

  15. Capture locations and growth rates of Atlantic sturgeon in the Chesapeake Bay

    USGS Publications Warehouse

    Welsh, S.A.; Eyler, S.M.; Mangold, M.F.; Spells, A.J.

    2002-01-01

    Little information exists on temporal and spatial distributions of wild and hatchery-reared Atlantic sturgeon Acipenser oxyrinchus oxyrinchus in the Chesapeake Bay. Approximately 3,300 hatchery-reared Atlantic sturgeon comprised of two size groups were released into the Nanticoke River, a tributary of the Chesapeake Bay, on 8 July 1996. During January 1996-May 2000, 1099 Atlantic sturgeon were captured incidentally (i.e., bycatch) by commercial watermen in the Chesapeake Bay, including 420 hatchery-reared individuals. Wild and hatchery-reared Atlantic sturgeon were captured primarily in pound nets and gill nets. Biologists tagged each fish and recorded weight, length, and location of capture. Although two adults greater than 2000 mm fork length (FL) were captured in Maryland waters, wild sturgeon were primarily juveniles from Maryland and Virginia waters (415 and 259 individuals below 1000 mm FL, respectively). A growth rate of 0.565 mm/d (N = 15, SE = 0.081) was estimated for wild individuals (487-944 mm TL at release) at liberty from 30 to 622 d. The average growth of the group of hatchery-reared Atlantic sturgeon raised at 10??C exceeded that of the group raised at 17??C. Our distributional data based on capture locations are biased by fishery dependence and gear selectivity. These data are informative to managers, however, because commercial effort is widely distributed in the Chesapeake Bay, and little distributional data were available before this study.

  16. Chesapeake Bay atmospheric deposition study phase 2: July 1990-December 1991. Final report

    SciTech Connect

    Baker, J.E.; Burdige, D.; Church, T.M.; Cutter, G.; Dickhut, R.M.

    1994-07-01

    The purpose of the study was to determine atmospheric loadings of selected trace elements and organic compounds directly to the surface waters of the Chesapeake Bay. The work in this report represents the first eighteen months of the Chesapeake Bay Atmospheric Deposition Study. Future reports will describe the integrate results from the CBADS network through September 1993. An 18 month field study (6/90 - 12/91), conducted to estimate the deposition of atmospheric trace contaminants to the Chesapeake Bay, represents Phase II of the Chesapeake Bay Atmospheric Deposition Study (CBADS). Previously reported data from Phase I (6/90 - 7/91) is presented here in concert with data from 7/91 - 12/91. The trace elements (aluminum, arsenic, cadmium, chromium, copper, iron, manganese, nickel, lead, selenium, and zinc), polychlorinated biphenyl (PCBs) congeners, and polycyclic aromatic hydrocarbons (PAHs) were measured in the ambient atmosphere and in precipitation. In addition several major ions, (chloride, sulfate, nitrate, sodium) were measured in precipitation at the three sites.

  17. Chesapeake Bay ecosystem modeling program. Technical synthesis report 1993-94

    SciTech Connect

    Brandt, S.B.; Boynton, W.R.; Kemp, W.M.; Wetzel, R.; Bartleson, R.

    1995-03-01

    ;Contents: Ecosystem models for management; Ecosystem regession models; Patuxent River Sav-Littoral Ecosystem Process Model; Lower Chesapeake Bay Polyhaline Sav Model; Emergent Intertidal Marsh Process Model; Plankton-Benthos Ecosystem Process Model; Fish Bioenergetics Models; Linking Water Quality with Fish Habitat; Data Visualization; Publications and Scientific Presentations Resulting From This Research.

  18. Biology and Identification of Rays in the Chesapeake Bay. Sea Grant Program. Educational Series Number 20.

    ERIC Educational Resources Information Center

    Smith, Joseph W.; Merriner, J. V.

    This booklet provides a brief discussion of the anatomy and biology of rays in the Chesapeake Bay and a key to their identification. Descriptions of seven types of rays are also provided (with accompanying illustrations). These include electric rays, stingrays, butterfly rays, eagle rays, cownose rays, and manta rays. (JN)

  19. Loadings of atmospheric trace elements and organic contaminants to the Chesapeake Bay

    SciTech Connect

    Baker, J.E.; Leister, D.L.; Church, T.M.; Scudlark, J.R.; Ondov, J.M.; Dickhut, R.M.; Cutter, G.

    1994-12-31

    To assess the absolute magnitude of atmospheric deposition loadings to the chesapeake Bay, a three-station network of integrated precipitation and air samplers was established in mid-1990 and maintained through September 1993. The objectives of the Chesapeake Bay Atmospheric Deposition Study (CBADS) were to document spatial and temporal variability in atmospheric inventories and wet and dry depositional fluxes of a variety of trace elements (Al, As, CD, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) and organic contaminants (polycyclic aromatic hydrocarbons, PCB congeners) in the chesapeake Bay region. Monthly wet depositional fluxes were calculated as the product of the volume-weighted mean concentration and the monthly precipitation amount, and annual dry deposition fluxes estimated as the product of particle-associated chemical inventories in the atmosphere and a size dependent deposition velocity. Total loadings to the surface waters of the Chesapeake Bay were estimated by spatially integrating fluxes from the three sites. PAH loadings (wet + dry) range from 19 {+-} 4 kg/year (anthracene) to 330 {+-} 86 kg/year (pyrene) and total PCB loadings were 40 {+-} 9 kg/year. Trace element loadings in 1991 ranged from 1,200 {+-} 130 kg/year for cadmium to 41,000 {+-} 14,000 kg/year for zinc. Results from the CBADS study will be compared and contrasted with those from the Great Lakes Integrated Atmospheric Deposition Network.

  20. Draft Genome Sequence of Synechococcus sp. Strain CB0101, Isolated From the Chesapeake Bay Estuary.

    PubMed

    Marsan, David; Wommack, K Eric; Ravel, Jacques; Chen, Feng

    2014-01-09

    Here, we report the draft genome sequence of the estuarine Synechococcus sp. strain CB0101. The genomics information of this strain will facilitate the study of the poorly understood Synechococcus subcluster 5.2 and how this strain is capable of thriving in a dynamic estuarine system, such as the Chesapeake Bay.