The ability of natural attenuation to mitigate agricultural nitrate contamination in recharging aquifers was investigated in four important agricultural settings in the United States. The study used laboratory analyses, field measurements, and flow and transport modeling for monitoring well transects (0.5 to 2.5 km in length) in the San Joaquin watershed, California, the Elkhorn watershed, Nebr...

Land use and land cover across 28 sub-basins within the Cosumnes Watershed, CA (1989 km) were correlated to nitrate-N and total suspended solids (TSS) loading between water years 1999 and 2001. The impact of human development on stream water quality was evident as both agricultural area and population density predicted TSS loading in a linear mixed effects model. In contrast to the TSS model, t...

Headwater ecosystems may have a limited threshold for retaining and removing nutrients delivered by certain types of land use. Nitrogen enrichment was studied in a Rocky Mountain watershed undergoing rapid expansion of population and residential development. Study sites were located along a 30-km transect from the headwaters of the Blue River to Lake Dillon, a major source of drinking water for...

Contamination of freshwater ecosystems with nitrate is a growing global concern. Although nitrate pollution is recognized as a cause of aquatic eutrophication, few studies have examined the possible physiological impacts of nitrate exposure. In this study, we surveyed several reproductive variables of viviparous female Gambusia holbrooki (Poeciliidae) captured from eight springs in Florida. The...

. Abstract: In an oligotrophic coastal zone, land drainage and atmospheric precipitation can temporarily modify the concentrations of specific dissolved compounds in local surface waters, mainly nutrient salts, setting up conditions for "new" primary production of phytoplankton. The Ubatuba region (23°30'S 45°06'W) is considered an oligo-mesotrophic region subject to a high average annual preci...

Deposition of sea salts is commonly elevated along the coast relative to inland areas, yet little is known about the effects on terrestrial ecosystem biogeochemistry. We examined the influence of NaCl concentrations on N, C, and P leaching from a coastal Oregon forest Andisol in two laboratory studies: a rapid batch extraction (approximately 1 d) and a month-long incubation using microlysimeter...

Miller, J.H. and Newton, M., 1983. Nutrient loss from disturbed forest watersheds in Oregon’s Coast Range. Agro-Ecosystems, 8: 153-167. Dissolved nutrients were monitored bi-weekly in stream water draining 14 upland watetzhcds in Oregon’s Coast Range after sprayin g with 2,4:5-T + 2,4-D, clrarcut harvesting and slash burning. Anion generation and leaching were primarily studied. The nitrate con...

long term monitoring programme on brine shrimp ( artemia sp.) is being carried out by the environment agency, abu dhabi, united arab emirates (ead) with the prime purpose of understanding the population dynamics, ecology and habitat requirements of artemia at al wathba lake, situated within al wathba wetland reserve, which is an artificial wetland near abu dhabi city. the present study, being a...

Concentrations and temporal changes in concentrations of nitrate and total dissolved solids (TDS) in groundwater of the Bunker Hill, Lytle, Rialto, and Colton groundwater subbasins of the Upper Santa Ana Valley Groundwater Basin were evaluated to identify trends and factors that may be affecting trends. One hundred, thirty-one public-supply wells were selected for analysis based on the availabi...