Physical Sciences and Mathematics Commons^™

Analytical Chemistry Of Plastic Debris: Sampling, Methods, And Instrumentation, Robert C. Hale, Meredith E. Seeley, Ashley E. King, Lehuan H. Yu

VIMS Books and Book Chapters

Approaches for the collection and analysis of plastic debris in environmental matrices are rapidly evolving. Such plastics span a continuum of sizes, encompassing large (macro-), medium (micro-, typically defined as particles between 1 μm and 5 mm), and smaller (nano-) plastics. All are of environmental relevance. Particle sizes are dynamic. Large plastics may fragment over time, while smaller particles may agglomerate in the field. The diverse morphologies (fragment, fiber, sphere) and chemical compositions of microplastics further complicate their characterization. Fibers are of growing interest and present particular analytical challenges due to their narrow profiles. Compositional classes of emerging concern include …

Atlantic Coast And Inner Shelf, David E. Krantz, Carl H. Hobbs Iii, Geoffrey L. Wikel

VIMS Books and Book Chapters

The continental margin of Virginia, and of North America more broadly, is the physical transition from the high elevation of the continent to the low of the ocean basin. This transition was created as rifting pulled apart the ancient supercontinent Pangaea to create the Atlantic Ocean basin. Tectonic forces fractured and stretched the bedrock to create a stair-step ramp that subsequently would be mantled with sediment built up by erosion and transport off the continent.

The Coastal Plain and Continental Shelf of Virginia are contiguous and discrete physiographic provinces of the continental margin delimited by the present elevation of sea …

Six Fish And 600,000 Thirsty Folks—A Fishing Moratorium On American Shad Thwarts A Controversial Municipal Reservoir Project In Virginia, Usa, J. E. Olney, Donna M. Bilkovic, Carl Hershner, Lyle M. Varnell, Harry V. Wang, Roger L. Mann

VIMS Books and Book Chapters

Moratoria on fishing directly impact fishers, distributors and marketers of product and can have serious socio-economic implications. Moratoria can impact communities but usually populations closely linked to the banned activity. In an unprecedented example, a moratorium on fishing in Virginia has directly impacted a nonfishing citizenry by thwarting plans for a public utility. In May 2003, a panel empowered to regulate marine resources denied permission to withdraw raw water from a pristine freshwater river, the Mattaponi. The controversial action spoiled a multi-million dollar plan to establish the King William Reservoir, a water source considered essential to future growth and development …

A Comparison Of Structural And Nonstructural Methods For Erosion Control And Providing Habitat In Virginia Salt Marshes, Karen A. Duhring

VIMS Books and Book Chapters

Shoreline stabilization methods that emphasize the use of tidal marshes and riparian vegetation are encouraged as a baseline defense for tidal shoreline erosion in Virginia. The effectiveness of three of these methods in preventing erosion and providing habitat was evaluated, including marsh stabilization structures (marsh toe revetments and sills), planted tidal marshes, and bank grading. This evaluation includes results from a recent field survey of 36 tidal marsh stabilization structures, permitting records, and other monitoring data. Marsh structures effectively reduced erosion of fringing and embayed marshes but were not as effective for gradually disappearing spit marshes. Adverse impacts of restricted …

Current Understanding Of The Effectiveness Of Nonstructural And Marsh Sill Approaches, Bhaskaran Subramanian, Gene Slear, Kevin M. Smith, Karen A. Duhring

VIMS Books and Book Chapters

A panel session at the Living Shorelines Summit in Williamsburg, Virginia was dedicated to the current understanding of the effectiveness of nonstructural erosion protection methods and marsh sills. Four panelists described their professional experience with either design and construction or monitoring of projects in tidal waters of Maryland and Virginia, including marsh edge stabilization (marsh toe revetments), marsh sills with sand fill, and planted marshes. Their collective experience revealed that planted tidal marshes and supporting structures can be effective alternatives to revetments and bulkheads. Site-specific engineering is required to ensure they provide functional ecological benefits, particularly in medium and high …

Submarine Sand Resources, Southeastern Virginia - Contributions From Year Nine And Year Ten Of Virginia’S Continental Margins Program, Carl Hobbs Iii, C. Scott Hardaway Jr., C. R. Berquist

VIMS Books and Book Chapters

Virginia’s Year-Nine and Year-Ten funds from the Continental Shelf Program were used to supplement other work funded by the Minerals Management Service in an ongoing Cooperative Agreement focused on the area offshore of southeastern Virginia. Year-Nine and Year-Ten funds facilitated interpretation of subbottom profiles and the analysis of sediment samples from cores and grabs. On Virginia’s sediment-starved continental shelf, deposits of material potentially suitable for use as beach nourishment or, perhaps, as construction aggregate occur in three stratigraphic settings, each with specific characteristics of morphology, grain-size gradients, likelihood of discovery, and physical ease of exploitation. All must be verified with …

Uniform Bottom Shear Stress And Equilibrium Hyposometry Of Intertidal Flats, Carl T. Friedrichs

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Hypsometry is the distribution of horizontal surface area with respect to elevation. Recent observations of tidal flat morphology have correlated convex hypsometry with large tide ranges, long‐term accretion and/or low wave activity. Concave hypsometry, in turn, has been correlated with small tide ranges, long‐term erosion and/or high wave activity. The present study demonstrates that this empirical variation in tidal flat hypsometry is consistent with a simple morphodynamic model which assumes tidal flats to be at equilibrium if maximum bottom shear stress (τ) is spatially uniform. Two general cases are considered: (i) dominance of τ by tidal currents, where τ is …

Resuspension Behavior In The Lower Chesapeake Bay, J.P. -Y Maa, C. -H. Lee

VIMS Books and Book Chapters

Using the VIMS Sea Carousel to conduct in-situ experiments in lower Chesapeake Bay, we found significant spatial a.nd temporal difference of the critical bed shear stress for sediment resuspension, tcr- At the Wolftrap site, tcr varied from 1.1 Pa in the summer to 1.9 Pa in the winter. At the Burwell Bay site, although the bed was too soft for anchoring our research vessel against the changing tide, we identified that tcr was 0.045 Pa. At the Old Plantation site, there was a small amount of fluffy material on top of the bed. At a winter deployment at the Cherrystone …

Evidence For A Relation Between A White Perch Young-Of-The-Year Index And Indices Of Later Life Stages, Thomas C. Mosca Iii, Herbert M. Austin, David M. Plotner

VIMS Books and Book Chapters

Juvenile indices are employed in fisheries management to predict the future abundance of harvestable adults. Frequently, regulations on the utilization of the resource, and a lack of fishery independent abundance data, make verification of the prediction accuracy impossible. In the case of white perch in Virginia, this is not so. Using the weighting system developed for a Chesapeake Bay-wide index of juvenile striped bass abundance based on summertime beach seine data collected in nursery ground waters, we developed a similar index for white perch in the Virginia portion of the Bay. Regressions against Virginia Institute of Marine Science otter trawl …

The Precarious State Of The Chesapeake Public Oyster Resource, William J. Hargis Jr., Dexter S. Haven

VIMS Books and Book Chapters

The 243,000 acres of Virginia's public oyster reefs (a.k.a. the Baylor Grounds) have been extremely productive of usable and saleable (market .md seed) oysters (Crassostrea virginica), oyster shells and oyster shell by-products. Archaeological remains and historical records show that they have yielded great numbers of whole oysters, oyster meats, oyster "seed" and shell since the 01esapeake was formed some 3,000 years BP. In the last century their natural productivity, as indicated by commercial harvest records (the only long-term data available), has declined markedly. In 1904, Vrrginia's total market (adult) oyster harvest was about 7.6 million bushels (mostly from public grounds). …

Transport Of Hypoxic Waters: An Estuary-Subestuary Exchange, A. Y. Kuo, K. Park

VIMS Books and Book Chapters

Hypoxic or anoxic conditions in the subpycnocline water of Chesapeake Bay persist throughout the summer. The effect on the dissolved oxygen concentration in the deep basin of the lower Rappahannock River, a subestuary on the western side of the bay, was studied with an observational program. The data indicate that in the lower portion of the water column the subtidal (or residual) current was directed into the subestuary most of the time. The mass fluxes of salt and dissolved oxygen into the subestuary through a point near the estuarine bottom at the river mouth were calculated for tidal and subtidal …

Central Atlantic Coastal Plain - A Summary Of The Geological Evolution Of Chesapeake Bay, Eastern United States, Steven M. Colman, Jeffrey P. Halka, C. Hobbs

VIMS Books and Book Chapters

The seaward margin of the U.S. Atlantic Coastal Plain has fluctuated through time, from near the Fall Line to near the edge of the present Outer Continental Shelf, owing to changes in relative sea level. The strata that underlie the Coastal Plain were deposited in environments that ranged from fully terrestrial to fully marine. Estuarine environments are critical components of the Coastal Plain; they represent the interface, otherwise known as the shoreline, between the marine and terrestrial depositional systems. The Quaternary evolution of estuaries has important implications for both documenting the history of sea-level changes and interpreting ancient coastal-plain strata. …

Ecological Functions And Values Of Nontidal Wetlands, Carl H. Hershner

VIMS Books and Book Chapters

Reviews the current understanding of the functions of nontidal wetlands, assesses the· problems of assigning values to wetland functions, and surveys the use of these functions and values in management programs of the mid-Atlantic states.

Ecological Risk Assessment For Highways In The Chesapeake Bay Watershed, Robert B. Atkinson, J. Cairns Jr., Bruce Wallace, James E. Perry

VIMS Books and Book Chapters

The population of coastal counties in the United States is over six-fold higher than non-coastal counties and population density along the Atlantic coast is much greater than all other coasts in the nation. Many areas around the Chesapeake Bay watershed are participating in this growth and extensive interstate construction is planned for this region. A wide array of primary ecological risks to the Chesapeake Bay exists, and may be classified as biological, physical, or chemical. Biological risks range from physical threats to motorists and animals to genetic risks to local flora and fauna populations. Island biogeography theory can be used …

Groundwater Nutrient Discharge To The Chesapeake Bay: Effects Of Near-Shore Land Use Practices, E. Laurence Libelo, William G. Macintyre, Gerald H. Johnson

VIMS Books and Book Chapters

Groundwater discharge supplies a significant portion of the inorganic nutrients entering the Chesapeake Bay. This discharge increases nutrient concentration in surface waters, which may result in increased macrophyte growth, reductions in· submerged aquatic vegetation and alteration of habitat. Human activities adjacent to the shoreline greatly increase nutrient concentration in the underlying groundwater, and so affect the overall nutrient input by groundwater seepage. In order to quantify the effect of land use on groundwater nutrient loading in the Virginia coastal plain we have installed monitoring wells in a variety of near shore environments adjacent to the James and York Rivers. Since …

Prototype For A Regional Online Toxics Database, Charles A. Lunsford, Craig L. Smith

VIMS Books and Book Chapters

An interactive online computerized database for retrieval of chemical analytical information on volatile and extractable organic compounds, and the priority pollutant metals has been developed. Current information about samples from the Chesapeake Bay region in Virginia and Maryland are available. This database stores information on organic compounds in effluent, water, tissue, and sediment in a format which does place restrictions on the number of compounds per sample. It includes various QA/QC items as well as the analyst's assessment of the validity of the data. A variety of keyed retrieval options permits selection of reporting format, and flagging of items exceeding …

Acoustic Geology Of A Portion Of Virginia's Innermost Continental Shelf, Carl H. Hobbs Iii

VIMS Books and Book Chapters

Side-scan sonography of the innermost continental shelf between Cape Henry and the Virginia-North Carolina border depicts a relatively typical inner shelf bottom generally characterized by medium density, meso-scale roughness. Subbottom acoustic protiles depict the stratigraphy as a Tertiary age basement separated from Quatenary-age deposits by a regional, angular(?) unconformity. Holocene-age sediments form a discontinuous layer above another unconformity. The area's topography appears to be a function of the presence of the modern sediments.

Heavy Mineral Concentrations In Sediments Of The Virginia Inner Continental Shelf, C. R. Berquist Jr., C. T. Fischler, L. J. Calliari, Et Al

VIMS Books and Book Chapters

The Virginia Division of Mineral Resources and the Virginia Institute of Marine Science investigated the occurrence of heavy minerals in the offshore sediments of Virginia. We began the project because earlier reconnaissance studies reported high heavy-mineral concentrations from several samples collected off the Eastern Shore of Virginia. Our work confirms the previously reported mineral values and locates additional high concentrations up to 20 nautical miles offshore. Furthermore, we show that potentially economic mineral values are not restricted no surficial sediments, but also are found in the upper 15 to 20 feet of inner continental shelf sediments. Several core samples indicate …

The Dynamics Of Long-Term Mass Transport In Estuaries, John M. Hamrick

VIMS Books and Book Chapters

The dynamics of long-term mass transport in estuaries having weakly nonlinear long wave dynamics are investigated. Low pass filtered long-term mass transport equations are derived for conditions of weak and strong vertical stratification. The dynamics of the residual mass transport velocity, or lowest order approximation to the Lagrangian residual velocity, are investigated by perturbation analyses of the hydrodynamics equations. For weak vertical stratification conditions, analytical results showing the influence of topography, the earth's rotation, and channel curvature on the distribution of the residual mass transport velocity field are presented. The calculation of the residual mass transport velocity field from field …

Heavy Mineral Variability And Provenance Of The Virginia Inner Shelf And Lower Chesapeake Bay, L. J. Calliari, C. T. Fischler, C. R. Berquist Jr.

VIMS Books and Book Chapters

The mineral composition of the 3- to 4-phi (0.125 to 0.063 mm) size fraction of 49 surficial grab samples,located north and south of the entrance to Chesapeake Bay and of 38 surficial samples, located in the bay mouth, was determined during this study. Although up to 17 minerals were identified, principal components analysis indicated that seven minerals accounted for 96 percent of the composition variance in the bay samples. By using Q-mode factor analysis, three mineral composition end-members (factors) were selected from the sample data and provided an adequate description of the spatial variation in heavy-mineral composition. The end members …

A Procedure For Assessing Heavy Mineral Resources Potential, Andrew E. Grosz, C. R. Berquist Jr., C. T. Fischler

VIMS Books and Book Chapters

Supplies of placer heavy minerals, such as ilmenite, rutile, zircon, and monazite, are anticipated to be in short supply by early in the next century. The depletion of conventional onshore deposits coupled with the declaration of the Exclusive Economic Zone in 1983 have provided the impetus to assess the resource potential of heavy-mineral concentrations in U.S. Continental Shelf sediments as future sources for these mineral commodities.

Mineralogically imprecise assessments of placer resources result from analyses of concentrates derived from small volume samples because of the particle-sparsity effect. The overall low grade of heavy minerals in Atlantic Continental Shelf sediments require …

Quaternary Geology Of The Chesapeake Bay, Jeffrey P. Halka, Steven M. Colman, Carl H. Hobbs Iii

VIMS Books and Book Chapters

The Chesapeake Bay, which is a classic coastal plain estuary, is located on a trailing edge continental margin. It has a surface area of nearly 6,000 km2 and ranges in width from 8 to 48 km. The morphology of the bay clearly reflects its formation as a response to fluctuating sea level during and following the last major continental glaciation. The shoreline is highly irregular, the tributaries form an intricate dendritic drainage pattern, and a deep axial channel occurs along much of its length (fig. 1). Water depths commonly exceed 30m in this deep channel, which is flanked by broad …

Monitoring Seagrass Distribution And Abundance Patterns: A Case Study From The Chesapeake Bay, Robert J. Orth, Kenneth A. Moore, Judith F. Nowak

VIMS Books and Book Chapters

Seagrasses, or submerged aquatic vegetation (SA V), have been mapped in the Chesapeake Bay five times between 1978 and 1987 with standard aerial photographic techniques, resulting in annual reports on SAV distribution. Acquisition of the vertical photography at a scale of 1:24,000, adhering to strict quality-assurance guidelines based on sun angle, tidal stage, cloud cover, wind speed, and season, has produced excellent, high-contrast imagery delineating beds of SAV from adjacent, unvegetated areas. Ground-truthing data from various State, Federal, and public organizations have corroborated the photographic data base. (more ...)

Persistence Of Residual Currents In The James River Estuary And Its Implication To Mass Transport, Albert Y. Kuo, John M. Hamrick, Gamble M. Sisson

VIMS Books and Book Chapters

The distribution and persistence of Eulerian and Lagrangian residual velocity in a cross sectional transect of the James River estuary, Virginia are analyzed. The Eulerian residual velocity has the characteristic two-layered estuarine circulation in the northern half of the transect, however, the net flow is directed downriver at all depths in the shallower southern half of the transect. In the deep channel, the two-layered Eulerian residual circulation is highly persistent over the six month study duration, with disruptions occurring less than 10% of the time when meteorological forcings are intense. No spring-neap tidal cycle variation is apparent. The magnitude of …

Kepone And The James River, Robert J. Huggett

VIMS Books and Book Chapters

The James River in Virginia was contaminated by the pesticide kepone when the material entered the river as early as 1968 and continued until its discovery in 1975. The river became so contaminated that commercial fisheries were closed. In 1988, 13 years after closure, all fishing restrictions were lifted. The contaminated sediments have been diluted and covered enough by uncontaminated material that the kepone flux back into the water column has diminished. Kepone concentrations in organisms inhabitating the river are finally below the U.S. Environmental Protection Agency and Food and Drug Administration action levels. Biological, chemical, physical and geological aspects …

The Response Of Estuarine Circulation To Local Wind Events, K. P. Kiley, C. S. Welch

VIMS Books and Book Chapters

An analysis of non-tidal estuarine circulation and local wind events was conducted employing wind and current records taken along the York River. Three distinct response conditions of non-tidal circulation to wind were observed. These conditions exhibited significant temporal and spatial variability. The first was typified by a positive two layer flow response to wind that was significant in the middle section of the York during the first six days of the study. The second exhibited a positive one layer flow response to wind that was significant in the upper section of the York during the last three days of the …

Interaction Between Circulation Of The Estuary Of The James River And Transport Of Oyster Larvae, Evon P. Ruzecki, William J. Hargis Jr.

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Hydraulic model dye test results are examined to provide estimates of nontidal horizontal circulation and movement/retention of oyster larvae in the James River Estuary. Test conditions maintained a constant mean tide and average summer low freshwater discharge. It was assumed that movement of dye in the model would approximate movement of the planktonic (larval) stages of oysters (Crassostroa virginica) in the prototype. Test results were used to rank six dye release points (candidate brood stock locations) with respect to relative quantities of dye retained in areas of the model representing commercially important seed oyster beds during the period 20-40 tidal …

Chesapeake Bay Fisheries: An Overview, Herbert M. Austin

VIMS Books and Book Chapters

The value of the marine resources of the Chesapeake Bay is second only to its value as a transportation corridor. The oyster, blue crab and striped bass or rock fish, along with the sailboat, epitomize our vision of the Bay. Nowhere else do such important renewable natural resources co-exist so closely to man's residential and industrial activities.

Over time, all natural resource distribution and abundance fluctuates in response to a normally fluctuating environment. Man's harvest adds an additional pressure, and in some cases recruitment levels cannot keep pace with consumer demand. In the Bay, pollutants, both intentional point source discharge, …

A Socio-Economic Overview Of The Chesapeake Bay Fisheries, James E. Kirkley

VIMS Books and Book Chapters

The marine resources of the Chesapeake Bay are believed to provide substantial benefit to residents of the State of Maryland and Virginia. However, the possibility of overfishing and degradation of the marine environment seriously jeopardizes the possible benefit . In thsi section, a brief overview of the economic importance and characteristics of the Chesapeake Bay marine resources is presented. The potential for economic lossee are discussed relative to observed economic values.

Submerged And Emergent Aquatic Vegetation Of The Chesapeake Bay, Carl Hershner, Richard L. Wetzel

VIMS Books and Book Chapters

Chesapeake Bay supports a diverse assemblage of submerged and emergent aquatic vegetation. The distribution of species of each kind of vegetation is governed largely by salinity. The functions of both submerged and emergent vegetation in the Bay ecosystem includes contributing to total net primary production, service a habitat and performance in both water quality and sedimentation processes. Research on submerged aquatic vegetation is focused on its role in the estuarine system and determinants of its distribution and abundance. Research on emergent vegetation still concerns basic questions of structure and function, but has also branched into methodologies for utilization by man …