نتایج جستجو برای: silt and clay
تعداد نتایج: 16832467 فیلتر نتایج به سال:
The effects of four soil types, soil porosity, particle size, and organic matter were tested on survival and migration of Xiphinema americanum. Survival and migration were significantly greater in silt loam than in clay loam and silty clay soils. Nematode numbers were significantly greater in softs planted with soybeans than in fallow softs. Nematode survival was greatest at the higher of two p...
Analytical methods and numerical experiments are used to study salinization of groundwater in response to sea level rise. The system that is studied involves a saturated porous medium with an inclined upper surface. The upper surface is progressively inundated during sea level rise to simulate transgression, the landward migration of the shoreline. Four "modes" of seawater intrusion are disting...
Sediments from natural marsh and four microecosystem (MES) tanks were compared with reference to ATP, carbon content, and physical properties. Mean values for bacterial numbers and ATP were about twice as high in the MES, carbon content was slightly higher in the artificial systems, and the sediment of the MES was enriched for larger grain sizes and depleted of silt and clay. In the natural mar...
A case study is presented highlighting changes in geochemical conditions induced by the anaerobic degradation of petroleum hydrocarbons (PHCs) that enhanced the coalescence of dissolved phase PHCs into light non-aqueous phase liquid (LNAPL). Forensic analysis detected the presence of weathered light, middle and heavy weight PHCs in groundwater and LNAPL samples that were consistent with straigh...
Changes in nutrient concentrations and sediment texture of the seagrass beds were recorded for two years from July 1996 to June 1998 at monthly intervals at two stations (Station 1--Manoli island; Station 2--Chinnapalam) of the Gulf of Mannar Marine Biosphere Reserve. Different nutrients in water showed varied concentrations in different seasons. Phosphate concentration varied between 2.32 and ...
BACKGROUND Metsulfuron-methyl is widely used for controlling many annual grasses and broadleaf weeds in cereal crops. Nonetheless, increasing evidence has demonstrated that even extremely low levels of metsulfuron-methyl residues in soil can be toxic to subsequent crops or non-target organisms. The behavior of herbicides in soils is mostly related to their residual forms. The intent of the pres...
Francisella tularensis (FT) is gram negative, non-motile, capsulated and intracellular zoonotic fastidious bacteria, causing tularemia in both animals and human. Soil texture and heavy metals play an important role in survival and persistence of microbes in environment. In the present study, association of physical and chemical composition of soil was determined in 74 FT positive and negative s...
Different multivariate statistical analysis such as, cluster analysis, principal component analysis, and multidimensional scale plot were employed to evaluate the trophic status of water quality for four monitoring stations. The present study was carried out to determine the physicochemical parameters of water and sediment characteristics of Pondicherry mangroves-southeast coast of India, durin...
The relationship between a suite of physical and biological factors and drift macroalgal abundance was examined in 12 seagrass sites spanning a distance of over 50 km within Tampa Bay, Florida, USA. Field sampling was conducted in December 1991, and drift algal abundance was determined by recording algal percent cover from 25 quadrants at each site. Additionally, drift rnacroalgae were collecte...
To assess the potential impact of conifer encroachment on soil organic carbon (SOC) dynamics and storage in montane aspen-conifer forests from the interior western US, we sampled mineral soils (0–15 cm) across the aspen-conifer ecotones in southern and northern Utah and quantified total SOC stocks, stable SOC (i.e., mineral-associated SOC (MoM)), labile SOC (i.e., light fraction (LF), decomposa...
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