A "step dynamics" model is developed for mound formation during multilayer homoepitaxy. Downward funneling of atoms deposited at step edges is incorporated and controls mound slope selection. Behavior of the selected slope differs from that predicted by phenomenological continuum treatments where the lateral mass current vanishes identically. Instead, this current is shown to vary periodically ...

Activities of Pa and Th in surface sediments from the Arctic Ocean and Greenland–Norwegian Seas are used to examine the redistribution of these water-column produced tracers between the low productivity interior basins and high particle flux marginal areas. Sediment 231Paxs/ 230Thxs ratios throughout the Canadian and Eurasian Basins and the high particle flux Chukchi slope region are essentiall...

tivity phenomenon that is widely accepted as indicating the base of the gas-hydrate stability zone. The acoustic impedance difference between sediments invaded with gas hydrate above the BSR and sediments without gas hydrate, but commonly with free gas below, are accepted as the conditions that create this reflection. The relationship between BSRs and marine gas hydrate has become so well known...

The Clinch River in Virginia and Tennessee, USA, is well known for its diverse native freshwater mussel assemblages; however, notable declines in mussel populations in recent decades have prompted much concern and subsequent research. The authors examined the toxicity of recently deposited sediments on juveniles of the freshwater mussel Epioblasma brevidens by collecting time-integrated sedimen...

in this study, the concentrations of heavy metals (ca, zn, cu, fe, mn, ni) in thesediment of shavoor river in khuzestan province in iran has been investigated. after the library studies and field studies, six samples of water and sediment were taken from the river in order to evaluate heavy metal pollution in sediments. to determine the geochemical phases of metals in sediment samples the 5-ste...

Disturbance strongly impacts patterns of community diversity, yet the shape of the diversity-disturbance relationship remains a matter of debate. The topic has been of interest in theoretical ecology for decades as it has practical implications for the understanding of ecosystem services in nature. One of these processes is the remineralization of organic matter by microorganisms in coastal mar...

Soot black carbon (here expressed as GBC) is present in sediments of Central Park and Prospect Park Lakes, New York City (NYC), and peaks in the middle of the 20th Century at the highest values (1-3% dry weight) ever reported in urban lakes. During that period (approximately 1940-1970), the GBC represents up to 28% of the total organic carbon (OC). Radionuclide-normalized whole core inventories...

The consequences of a sudden decrease in water salinity on a macrophyte community dominated by the marine species Zostera noltii were investigated in a shallow coastal lagoon (Southern France). The expected change in the community assemblage was a competitive displacement of Z. noltii by Potamogeton pectinatus and Ruppia cirrhosa. However, the results of an eight-year survey did not validate th...

Residual doses may cause overestimation of electron spin resonance (ESR) ages for fluvial sediments. However, ESR residual in outburst megaflood sediments have rarely been evaluated. The Jinsha River, situated the southeastern Tibetan Plateau, is characterized by active faults, narrowed canyons, and dammed lakes. Consequently, river a rare opportunity reconstruction study flood events from pale...