Physical Sciences and Mathematics Commons^™

Ammonium Cycling And Nitrifier Community Composition In Eutrophic Waters Affected By Cyanobacterial Harmful Algal Blooms, Justyna J. Hampel

Browse all Theses and Dissertations

Non-point source nitrogen (N) from agriculture is a main driver of eutrophication in aquatic systems, which often manifests as toxin producing cyanobacterial harmful algal blooms (cyanoHABs). Non-N2 fixing cyanobacteria, such as Microcystis, thrive on chemically reduced N forms (e.g., ammonium (NH4+) and urea) used as the main N form in fertilizer. NH4+ turnover rates are important components of the aquatic N cycle in eutrophic lakes affected by cyanoHABs. Regeneration of NH4+ can contribute to the internal cycling of NH4+, which can sustain cyanoHABs when external loads are low. Additionally, NH4+ uptake by cyanobacteria competes directly with nitrification, another important pathway …