نتایج جستجو برای: surface sediment
تعداد نتایج: 666636 فیلتر نتایج به سال:
Concentrations of volatile organic sulfur compounds (VOSC) were measured in water and sediment columns of ditches in a minerotrophic peatland in The Netherlands. VOSC, with methanethiol (4 to 40 nM) as the major compound, appeared to be mainly of sediment origin. Both VOSC and hydrogen sulfide concentrations decreased dramatically towards the water surface. High methanethiol and high dimethyl s...
In soft-sediment systems, terrestrial sediment deposits may result in a marked change in habitat and benthic community composition. We conducted a series of experiments to investigate the behavioural response of juveniles of 2 bivalve species common on New Zealand intertidal sandflats (Paphies australis and Macomona liliana) to terrestrial sediments. Both species are able to actively disperse a...
Many physical and chemical processes control the extent of Fe(III) oxyhydroxide reduction by dissimilatory Fe(III)-reducing bacteria. The surface precipitation of secondary Fe minerals on Fe(III) oxyhydroxides limits the extent of microbial Fe(III) reduction, but this phenomenon has not yet been observed in nature. This paper reports the observation of secondary Fe-mineral (goethite) encrustati...
چکیده ندارد.
abstract gully erosion is a kind of water erosion that has high priority in fars province due to sediment production and enormous damages to land, roads and infrastructures. in this study, 15 gullies were selected and their morphometric characteristics, such as catchment area, soil, cover vegetation and climate were measured. in order to determine influential factors on the sediment production ...
background: soil and sediment serve as major reservoir for contaminants as they possess ability to bind various chemicals together. in this study the concentrations of heavy metals cd, cr and cu were analyzed in surface sediments of agh gel wetland in west of iran. methods: the sediment samples were taken from 10 stations. the samples were subjected to bulk digestion and chemical partitioning a...
Diverse faunal groups inhabit deep-sea sediments over much of Earth's surface, but our understanding of how interannual-scale climate variation alters sediment community components and biogeochemical processes remains limited. The vast majority of deep-sea communities depend on a particulate organic carbon food supply that sinks from photosynthetically active surface waters. Variations in food ...
Rill erosion is considered to be the most important process affecting soils created by the concentrated flow of water. In this research to quantify sediment transport and runoff in natural rills, two rill experiments under dry and wet conditions were accomplished in November 2013 in the Golestan Dam. Filed experiments lead to a closer understanding of the dynamics and power of different soil er...
The effects of surface gravity waves on pore-water release from permeable sediment (k 5 1.3–1.8 3 10211 m2) in shallow water were studied in a wave tank. Our tracer experiments demonstrated that shallow-water waves can increase fluid exchange between sandy sediment and overlying water 50-fold, relative to the exchange by molecular diffusion. The main driving force for this increased exchange ar...
In this paper, we present the Daily based Morgan–Morgan–Finney model. The main processes in this model are based on the Morgan–Morgan–Finney soil erosion model, and it is suitable for estimating surface runoff and sediment redistribution patterns in seasonal climate regions with complex surface configurations. We achieved temporal flexibility by utilizing daily time steps, which is suitable for...
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