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POSTER INFORMATION
'Calcium Carbonate Co-Precipitation with Phosphorus: Developing a Novel Technique for Reconstructing Historic Lake Trophic States' Poster Poster: Anthropogenic phosphorus pollution is the leading cause of the eutrophication and degradation of water bodies. Managing these systems requires an accurate understanding of historical conditions. However, the vertical mobility of phosphorus (P) in lake sediments has prevented accurate determinations of historical loading. Because P has a high affinity for Ca, and will co-precipitate with CaCO3 in lake systems, we hypothesize the CaCO3-P fraction of sediments can accurately reconstruct historical ambient water column concentrations. We precipitated CaCO3 in a range of P solutions (0,5,25,50,100,250 ug/L) and found the precipitates had P concentrations that closely match the solution from which they formed (R2=0.9959, P=<0.001). Our research now focuses on P inclusions in individual grains, employing SEM microscopy and microprobe analyses to develop a way to quantify CaCO3-P concentrations.We anticipate developing a calibration relating P concentrations in CaCO3 to P concentrations in the solution from which the grains precipitate. Our results will inform a new approach to measuring trophic history of alkaline, calcareous lakes. Specifically, this method may inform debates regarding whether Utah Lake was eutrophic before large-scale development within the watershed.
SPEAKER INFORMATION
PRESENTER(S): Mark Devey - Janice Brahney - Bio: Janice received her doctorate from the University of Colorado, Boulder from the Department of Geological Sciences. Her doctorate examined the potential for dust to transport nutrients and base-cations to freshwater ecosystems. During her MS she spent time at both Simon Fraser University and the University of Waterloo where she examined climate change impacts on watershed hydrology and lake level fluctuations. Janice also holds a BS in Environmental Science with a minor in Geology from Simon Fraser University. Her undergraduate research examine top-down and bottom-up effects of salmon in costal lakes. Prior to arriving at USU, Janice was a post-doctoral scientist at the University of British Columbia, Okanagan, where she led projects on the water quality and quantity issues in the Canadian Columbia Basin.