Biochemical and traditional methods were used to determine the influence of Caflianassa trilobata on microbiological and meiofaunal communities within its large, hghly consolidated burrow. Sediment was collected from the lining of the shrimp's burrow, the burrow matrix, and ambient, subsurface sediment. The lining and matrix were composed of poorly sorted, fine-grained material compared to sand...

Two chemical approaches, Tenax extraction and matrix solid phase microextraction (matrix-SPME), were evaluated as surrogates to estimate bioavailability of polychlorinated biphenyls (PCBs) from field-contaminated sediment. Aroclor 1254 was the primary contaminant found in sediment from Crab Orchard Lake in Marion, Illinois, USA, and a total of 18 PCB congeners were selected for study. Bioaccumu...

Understanding and defining the spatial distribution of sediment deposited in reservoirs is essential not only at the design stage but also during the operation. The majority of research concerns the distribution of sediment deposition in medium and large water reservoirs. Most empirical methods do not provide satisfactory results when applied to the determination of sediment deposition in small...

A falling rigid body through air, water, and sediment is investigated experimentally and theoretically. Two experiments were conducted to drop rigid cylinders with density ratio around 1.8 into shallow water (around 13 m deep) in the Monterey Bay (Exp-1) and into the Naval Postgraduate School’s swimming pool (Exp-2). During the experiments, we carefully observe cylinder track and burial depth w...

Extended survival of fecal bacteria in sediment can obscure the source and extent of fecal contamination in agricultural settings. The variability in fecal coliform/fecal streptococci (FC/FS) ratios with time and discrepancies between observable fecal sources and measured FC/ FS ratios in shallow surface water from agricultural watersheds may be explained by examining FC and FS mortality rates ...

Sediment resuspension occurs in the global ocean, which greatly affects material exchange between the sediment and the overlying seawater. The behaviours of carbon, nutrients, heavy metals, and other pollutants at the sediment-seawater boundary will further link to climate change, eutrophication, and marine pollution. Residual β activity of particulate (234)Th (RAP234) is used as a novel proxy ...

Engineered flood bypasses, or simplified conveyance floodplains, are natural laboratories in which to observe floodplain development and therefore present an opportunity to assess delivery to and sedimentation within a specific class of floodplain. The effects of floods in the Sacramento River basin were investigated by analyzing hydrograph characteristics, estimating event-based sediment disch...

Vegetation change, whether it be of anthropogenic or climatic origin, can have dramatic effects on landscape form, processes and sediment yield. General conceptual models for relationships between climate, vegetation and sediment yield exist for whole landscapes, but no rigorous analysis of the effects of vegetation change on sediment transport, in the absence of overland flow, has been done fr...

Bioturbation can modify the biogeochemical properties of cohesive sediments and affect sediment stability. Here, we investigate the effects of the clam, Scrobicularia plana, on the erodibility of estuarine sediments. Muddy sediments with different mud contents were collected with minimal disturbance at Ponta da Erva, Hortas and Samouco in the Tagus Estuary. S. plana 40.7±0.3 mm length, (mean ± ...

a great challenge in using natural polysaccharide as drug delivery system is their fast drug release. the purpose of the present study was to prepare and evaluate chitosan oligosaccharide (cho)-de-estrifiedtragacanth (det) core-shell nanoparticles for controled release of water soluble drugs. cho-det nanoparticles were prepared by microemulsion method and characterized by ft-ir spectroscopy. si...