2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
6/06/2017 | 2:30 PM - 2:45 PM | LOCAL AND LARGE SCALE NUTRIENT DYNAMICS IN A METAL-CONTAMINATED RIVER | 306A
LOCAL AND LARGE SCALE NUTRIENT DYNAMICS IN A METAL-CONTAMINATED RIVER
Excessive and persistent inputs of nutrients into mid-order rivers can cause and sustain net autotrophic states over long periods of time. In the Upper Clark Fork River (UCFR), Montana, augmented autochthonous production takes the form of nuisance algal blooms and poses a threat to successful ecological restoration including removal of metal-contaminated sediments across the river’s floodplain. Despite a relative lack of evident point sources, river restoration and recovery is occurring under nutrient-rich conditions due to an average net gain of inorganic nitrogen (N) and phosphorous (P) within in the UCFR headwaters of 78.5±20.7 kg N-NO3/d and 11.6±2.3 kg P-PO4/d, respectively. Abundant P results from P-rich geologic formations in the basin, while preliminary results of dual isotope analysis of NO3 suggest nitrified soil N and animal/human waste as primary N sources with seasonal 15N-NO3 and 18O-NO3 values ranging within 5.1-19.4‰ and -6.2-2.1‰, respectively. Results for local interactions among algal standing stocks, dissolved inorganic nutrients, and organic N and P show a robust seasonality leading to sustained P:R ratios greater than one and N-limiting conditions (<0.005 ppm N-NO3) throughout base flow conditions.
- C27 Landuse and Non-Point source Impacts
- C06 Large River Ecology
- C10 Biogeochemistry
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Presenters/Authors
Marc Peipoch
(), Stroud Water Research Center, mpeipoch@stroudcenter.org;
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H. Maurice Valett
(), University of Montana, Division of Biological Sciences, maury.valett@umontana.edu;
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