نتایج جستجو برای: watersheds
تعداد نتایج: 5005 فیلتر نتایج به سال:
Understanding interactions between permanently frozen soils and stream chemistry is important in predicting the effects of management, natural disturbance and changing permafrost distribution on stream ecosystems and nutrient budgets in subarctic watersheds. Chemical measurements of groundwater, soil water and stream water were made in two watersheds in the taiga of interior Alaska. One watersh...
In 2009, a paper was published suggesting that watersheds provide a geospatial platform for establishing linkages between aquatic contaminants, the health of the environment, and human health. This article is a follow-up to that original article. From an environmental perspective, watersheds segregate landscapes into geospatial units that may be relevant to human health outcomes. From an epidem...
Study sites The study sites were located along the northeast shore of Lake Tanganyika providing an ideal comparison between forested and deforested watersheds. Seven contrasting streams were studied; four of these streams were located in forested watersheds within the Gombe Stream National Park. Vegetation in Gombe Stream National Park consists of semi-deciduous woodland, wetter canopy forests ...
A survey of numerous field studies shows that nitrogen and phosphorous export coefficients are significantly different across forest, agriculture, and urban land-cover types. We used simulations to estimate the land-cover composition at which there was a significant risk of nutrient loads representative of watersheds without forest cover. The results suggest that at between 20 percent and 30 pe...
Linking fecal indicator bacteria concentrations in large mixed-use watersheds back to diffuse human sources, such as septic systems, has met limited success. In this study, 64 rivers that drain 84% of Michigan's Lower Peninsula were sampled under baseflow conditions for Escherichia coli, Bacteroides thetaiotaomicron (a human source-tracking marker), landscape characteristics, and geochemical an...
........................................................................................................................................................ 195 Introduction .................................................................................................................................................. 195 Geological Control of Sudbury’s Lakes .........................................
OBJECTIVE To monitor the presence of pharmaceutical residues of 14 psychoactive drugs belonging to three therapeutic groups in the watersheds of Galicia (Spain). METHOD Five sewage treatment plants were selected in the main cities of Galicia. Thirteen psychoactive pharmaceutical compounds and one metabolite were chosen. In addition, tap water samples were taken from public places and private ...
[1] The hydrologic and biogeochemical responses of forested watersheds to inputs of rainfall and snowmelt can be an indicator of internal watershed function. In this study, we assess how the quantity and quality, both chemical and spectroscopic, of stream water DOC changes in response to a 6-day storm event during the wet season of 2003 in three small (<1 km) basins in the H. J. Andrews Experim...
Mercury (Hg) stored in vegetation and soils is known to be released to the atmosphere during wildfires, increasing atmospheric stores and altering terrestrial budgets. Increased erosion and transport of sediments is well-documented in burned watersheds, both immediately post-fire and as the watershed recovers; however, understanding post-fire mobilization of soil Hg within burned watersheds rem...
The use of antibiotic resistance analysis (ARA) for microbial source tracking requires the generation of a library of isolates collected from known sources in the watershed. The size and composition of the library are critical in determining if it represents the diversity of patterns found in the watershed. This study was performed to determine the size that an ARA library needs to be to be rep...
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