Masters Thesis Defense | Michelle Catherine Kelly | Aquatic Biogeochemistry

THESIS TITLE: High Supply, High Demand: A Unique Nutrient Addition Decouples Nitrate Uptake and Metabolism in a Large River
General Information & Corrections ↓

GENERAL INFORMATION:

Michelle Catherine Kelly
Committee: Dr. Amy Burgin (Chair, Advisor), Dr. Admin Husic, and Dr. Ben Sikes
Masters Thesis Defense, 26 April 2019
Department of Ecology and Evolutionary Biology
University of Kansas

CORRECTIONS (thank you, committee):

13:42 "Larger rivers generally have more variable flow [than smaller streams]" May be true for some systems (e.g. watersheds dominated by temperate forest) but not a good generalization across the board

23:06 The calculation used here is a modified version of the equation presented in Heffernan and Cohen 2010, and uses a set channel length (L) to scale nitrate uptake, instead of using mean channel depth. As it's more common to scale rates using channel depth, this is likely a discrepancy between our data and the rates presented in the meta analysis figures. To address this (as of 1 May 2019), I've instead scaled nitrate uptake by modeled channel depth (using the depth modeling equation from Leopold & Maddock 1953 and constants from Raymond et al. 2012). Modeled channel depth has good agreement with USGS stream gauging data (R2 = 0.91 at S3). The depth-scaled nitrate uptake rates also follow the same patterns as presented in this talk (e.g. the story remains the same).

51:24 In addition to ammonium and nitrate, the waste storage ponds also contained high concentrations of organic carbon, due to biomass growth & decomposition. We saw elevated dissolved organic carbon concentrations in the Kansas River, with the highest levels nearest the waste release point.

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