Seagrass beds alter their hydrodynamic environment by inducing drag on the flow, thereby attenuating wave energy and near-bottom currents. This alters the turbulent structure and shear stresses within and around the seagrass bed that are responsible for the suspension and deposition of sediment. To quantify these interactions, velocity, pressure, and sediment measurements were obtained across a...

This study is a preliminary examination of heavy metal pollution in sediments close to two mine sites in the upper part of the Jequetepeque River Basin, Peru. Sediment concentrations of Al, As, Cd, Cu, Cr, Fe, Hg, Ni, Pb, Sb, Sn, and Zn were analyzed. A comparative study of the trace metal content of sediments shows that the highest concentrations are found at the closest points to the mine sit...

Fries et al. (1999), hereafter referred to as FBW, present interesting experimental data showing that biogenic mounds, formed by the conveyor-belt feeding polychaete Cistenides (Pectinaria) gouldii, can be reshaped into asymmetric bedforms at bed shear stresses below the Shields threshold of sediment movement. The ®nal geometry of the current ripples was found to depend on the spatial density o...

At the smallest scales of sediment transport in rivers, the coherent structures of the turbulent boundary layer constitute the fundamental mechanisms of bedload transport, locally increasing the instantaneous hydrodynamic forces acting on sediment particles, and mobilizing them downstream. Near the critical threshold for initiating sediment motion, the interactions of the particles with these u...

The Soil and Water Assessment Tool (SWAT) is used worldwide for water quality assessment and planning. This paper aimed to assess and adapt SWAT hillslope sediment yield model (Modified Universal Soil Loss Equation, MUSLE) for applications in large basins, i.e. when spatial data is coarse and model units are large; and to develop a robust sediment calibration method for large regions. The Upper...

The present study has investigated a correlation between the kinetics of polychlorinated biphenyl (PCB) dechlorination and the growth of dechlorinating microbial populations. Microorganisms were eluted from Aroclor 1248-contaminated St. Lawrence River (NY, USA) sediments and inoculated into clean sediments spiked with Aroclor 1248 at 10 concentrations ranging from 0 to 3.12 micromol/g sediment ...

BACKGROUND Tidal marshes will be threatened by increasing rates of sea-level rise (SLR) over the next century. Managers seek guidance on whether existing and restored marshes will be resilient under a range of potential future conditions, and on prioritizing marsh restoration and conservation activities. METHODOLOGY Building upon established models, we developed a hybrid approach that involve...

Nereis diversicolor is a widely distributed estuarine polychaete worm that is particularly abundant in the mid to upper parts of estuaries. Laboratory annular flumes were used to study the effects of N. diversicolor density (0 [control], 100, 300, 1000, 3000 individuals m–2) on erodability of cohesive muddy sediments. At the highest densities (1000 and 3000 ind. m–2) there was evidence of activ...

Abstract. We develop a phenomenological model of suspended sediment transport on the basis data acquired in Capesterre river, which drains small tropical catchment Guadeloupe. The correctly represents concentration during floods, provided that relation between and water level forms counterclockwise loop. In model, properties river are all lumped into four parameters: settling velocity related t...

Concentrated seabed deposits of polymetallic nodules, which are rich in economically valuable metals (e.g., copper, nickel, cobalt, manganese), occur over vast areas of the abyssal Pacific Ocean floor. Little is currently known about the diversity of microorganisms inhabiting abyssal habitats. In this study, sediment, nodule, and water column samples were collected from the Clarion-Clipperton Z...