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Full-Text Articles in Physical Sciences and Mathematics
Tracking The Fate Of A High Concentration Groundwater Nitrate Plume Through A Fringing Marsh: A Combined Groundwater Tracer And In Situ Isotope Enrichment Study, Cr Tobias, Sa Macko, Iris C. Anderson, Elizabeth A. Canuel, Jw Harvey
Tracking The Fate Of A High Concentration Groundwater Nitrate Plume Through A Fringing Marsh: A Combined Groundwater Tracer And In Situ Isotope Enrichment Study, Cr Tobias, Sa Macko, Iris C. Anderson, Elizabeth A. Canuel, Jw Harvey
VIMS Articles
A groundwater plume enriched in (15)NO(3)(-) was created upgradient of a mesohaline salt marsh. By measuring the changes in concentration and isotopic enrichment of NO(3)(-), N(2)O, N(2), NH(4)(+), and particulate organic nitrogen (PON) during plume transport through the marsh, in situ rates of dissimilatory nitrate reduction to ammonium (DNRA) and denitrification (DNF) were estimated, as well as N storage in the reduced N pools. For groundwater discharge within the top 10 cm of marsh, NO(3)(-) removal was 90% complete within the 50 cm of marsh nearest the upland border. The peak NO(3)(-) loss rate from the plume ranged from 208 …
Sources And Cycling Of Dissolved And Particulate Organic Radiocarbon In The Northwest Atlantic Continental Margin, Je Bauer, Erm Druffel, Dm Wolgast, S Griffin
Sources And Cycling Of Dissolved And Particulate Organic Radiocarbon In The Northwest Atlantic Continental Margin, Je Bauer, Erm Druffel, Dm Wolgast, S Griffin
VIMS Articles
Continental shelves and slopes are productive and dynamic ocean margin systems that also regulate the fluxes of terrestrial, riverine, and estuarine materials between the continents and oceans. In order to evaluate the ages, potential sources, and transformations of organic matter in an ocean margin system, we measured the radiocarbon (Delta (14)C and delta (13)C distributions of total dissolved organic carbon (DOC), suspended particulate organic carbon (POC), and dissolved inorganic carbon (DIC) in waters of the Middle Atlantic Bight (MAB) continental shelf and slope in April-May 1994. The Delta (14)C of DOC was greatest (as high as -39 parts per thousand) …
Quantifying Groundwater Discharge Through Fringing Wetlands To Estuaries: Seasonal Variability, Methods Comparison, And Implications For Wetland-Estuary Exchange, Cr Tobias, Jw Harvey, Iris C. Anderson
Quantifying Groundwater Discharge Through Fringing Wetlands To Estuaries: Seasonal Variability, Methods Comparison, And Implications For Wetland-Estuary Exchange, Cr Tobias, Jw Harvey, Iris C. Anderson
VIMS Articles
Because groundwater discharge along coastal shorelines is often concentrated in zones inhabited by fringing wetlands, accurately estimating discharge is essential for understanding its effect on the function and maintenance of these ecosystems. Most previous estimates of groundwater discharge to coastal wetlands have been temporally limited and have used only a single approach to estimate discharge. Furthermore, groundwater input has not been considered as a major mechanism controlling pore-water flushing. We estimated seasonally varying groundwater discharge into a fringing estuarine wetland using three independent methods (Darcy's Law, salt balance, and Br- tracer). Seasonal patterns of discharge predicted by both Darcy's Law …
Post-Glacial Sedimentation In A River -Dominated Epicontinental Shelf: The Yellow Sea Example, Jing-Pu Liu
Post-Glacial Sedimentation In A River -Dominated Epicontinental Shelf: The Yellow Sea Example, Jing-Pu Liu
Dissertations, Theses, and Masters Projects
The North Yellow Sea (NYS) and South Yellow Sea (SYS), stretching from the Bohai Sea in the north to the East China Sea (ECS) in the south, represents an end member of modern epicontinental seas. Because of its shallow depths, the Yellow Sea was entirely exposed subaerially during the last glacial maximum. The new post-glacial sea-level curve derived from an extensive local dataset shows a series of rapid flooding events (12--45 mm/y), separated by a series of slow rises (2--6 mm/y). By about 15 ka, sea level had reached -100 m, and seawater entered the SYS. A rapid rise during …
Persistent Organic Pollutant Transport And Fate: Assessment By Molecular Tracers, Padma T. Venkatraman
Persistent Organic Pollutant Transport And Fate: Assessment By Molecular Tracers, Padma T. Venkatraman
Dissertations, Theses, and Masters Projects
Persistent organic pollutants (POPs) such as the organochlorine pesticide hexachlorocyclohexane (HCH) may undergo atmospheric transport and accumulate in regions remote from the source. It is important to develop techniques to help apportion source and identify transport or transformation processes to which HCHs and other mobile POPs may be subjected. Molecular tracers such as compound specific stable isotope and enantiomer ratios (ERs) may prove valuable in studying POP fate and transport. The objective of this study was to further develop the use of these two novel geochemical tools to evaluate the sources, transport and environmental fate of POPs, in the context …
A Study Of The Secondary Turbidity Maximum In The York River Estuary, Virginia, Jing Lin
A Study Of The Secondary Turbidity Maximum In The York River Estuary, Virginia, Jing Lin
Dissertations, Theses, and Masters Projects
A two-year period of monthly slack water survey results suggest that in addition to the classical estuary turbidity maximum (ETM), a second peak of bottom total suspended sediments (TSS) concentration, or a secondary turbidity maximum (STM), often exists in the mid-York Estuary. This STM, detected from majority of the slack water surveys, moves back and forth in the region of about 20--40 km from the York River mouth. Moreover, the distribution of potential energy anomaly indicates that the STM may be related to the stratification patterns of the water column. A mathematical analysis suggests that four processes may be important …
Modeling Of Critically-Stratified Gravity Flows: Application To The Eel River Continental Shelf, Northern California, Malcolm E. Scully
Modeling Of Critically-Stratified Gravity Flows: Application To The Eel River Continental Shelf, Northern California, Malcolm E. Scully
Dissertations, Theses, and Masters Projects
An analytical and numerical model are presented and applied to predict gravitydriven transport and deposition of fluid mud layers that form within the wave boundary layer on the continental shelf off the Eel River in northern California. Observations indicate that following floods of the Eel River down-slope transport of fluid mud trapped within the wave boundary layer is the dominant across-shelf transport mechanism. The models are based upon the assumption that following significant floods, an abundant supply of easily suspended fine sediment is delivered to the coastal ocean, allowing a negative feedback mechanism to maintain the near-bed Richardson number at …