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MP2 Amphibian Research and Monitoring
(102) Aquatic chemistry of amphibian breeding habitats in the mountains of western North America.
Campbell, D1, Muths, E2, Hossack, B3, Pilliod, D4, Hyde, E5, Corn, P3, 1 USGS, Denver, CO, USA2 USGS, Ft. Collins, CO, USA3 USGS, Missoula, MT, USA4 USDA-Forest Service, Missoula, MT, USA5 USGS, Corvallis, OR, USA
ABSTRACT- Aquatic habitats on federally-managed lands in the western United States are relatively undisturbed and uncontaminated compared to those in many parts of the World; nevertheless, some amphibian populations in these areas are in decline. We are measuring aquatic chemistry in these systems in order to determine amphibian vulnerability to stressors such as disease; climatic extremes (especially cold and drought); ultraviolet radiation; atmospheric deposition of acids, nitrogen, metals, and organic contaminants; and wildfire disturbance. Pond habitats have small catchments, and their aquatic chemistry is variable depending on topographic relief, geology, soils, and vegetation. Upland ponds are most sensitive to atmospherically-deposited contaminants: they are flushed with snowmelt during spring and their chemistry often remains dilute throughout the summer. Lowland ponds are fed by subsurface flowpaths with soil and ground water rich in weathering products and natural organic matter. Biogeochemical processes in the water column and bottom sediments play a larger role in ponds than in nearby lakes and streams, where terrestrial biogeochemical processes tend to dominate. During dry conditions, ponds often become closed systems, with little inflow or outflow. Water level fluctuations affect oxidation-reduction conditions that drive biogeochemical processes such as nitrogen and sulfur cycling. In a few of the ponds studied, concentrations of dissolved ammonium increased to as high as 1.0 mg/L late in summer.
Key words: water, amphibian, chemistry, mountain
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