The objectives of this project for FY98 have been to 1) participate in the analysis and interpretation of the bottom boundary layer field studies; 2) test and apply a 2-dimensional, time-dependent model of shelf sediment transport to investigate the importance of advection and flux divergence to event bed formation and the emplacement of flood deposits; and 3) incorporate flocculation effects i...

APPROACH COMOP sediment transport studies are funded by NOAA/NURP (observations) and ONR (modeling). Observational datasets collected at the Rutgers Long-term Ecosystem Observatory (LEO-15) and in the Gulf of Mexico provide model formulation and validation data. Our modeling strategy involves coupling a bottom boundary layer model to a shelf circulation model to examine three-dimensional patter...

Bacterial reduction of selenate [Se(VI)] to elemental Se [Se(0)] is considered an effective bioremediation technique to remove selenium (Se) from agricultural drainage water. However, the fate of the newly formed Se(0) in aquatic systems is not known when it flows out of the treatment system. A set of laboratory experiments was conducted to determine the fate of the colloidal-particulate Se(0) ...

In this paper the total concentration of As, Cr, Sb, pH and the red-ox potential of water and sediment samples of the Biała Przemsza River were determined. The arsenic (AB, MMA, DMA, As(III), As(V)), chromium (Cr(III), Cr(VI)) and antimony (Sb(III), Sb(V)) forms were studied by HPLC-ICP-MS. Ions were successfully separated on Hamilton PRP-X100: (AB, MMA, DMA, As(III), As(V)), Dionex Ion Pac AS-...

The relative impact of top-down control by herbivores and bottom-up control by environmental conditions on vegetation is a subject of debate in ecology. In this study, we hypothesize that top-down control by goose foraging and bottom-up control by sediment accretion on vegetation composition within an ecosystem can co-occur but operate at different spatial and temporal scales. We used a highly ...

Uranium behaves as a nearly conservative element in oxygenated seawater, but it is precipitated under chemically reducing conditions that occur in sediments underlying low-oxygen bottom water or in sediments receiving high fluxes of particulate organic carbon. Sites characterized by a range of bottom-water oxygen (BWO) and organic carbon flux (OCF) were studied to better understand the conditio...

Measurements of wave and suspended sediment concentration (SSC) were conducted near the 5-m isobath on the muddy inner shelf fronting Atchafalaya Bay, Louisiana, during Hurricane Claudette. The data show that wave and current activity resuspended large quantities of sediment, with SSC R 0.5 kg/m throughout the water column. In the waning phase of the storm, settling generated a suspension layer...

In natural waters, the equilibrium state of hydrophobic organic compounds among bottom sediment (BS), suspended sediment (SPS), and water is fundamental to infer their transfer flux and aqueous bioavailability. However, this type of information remains scarce and fragmented. This study systematically evaluated the equilibrium state of polycyclic aromatic hydrocarbons (PAHs) in the Yangtze River...

Excitation–emission matrix (EEM) fluorescence spectroscopy was employed to study the chemical nature of organic matter readily released into solution from sediment particles during episodes of resuspension. Surface sediment samples collected from five locations within the Hudson River Estuary and the Inner New York Bight were resuspended in their respective bottom waters for periods ranging fro...

Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide.