Terrestrial and Aquatic Ecology Commons^™

Urea As An Effective Nitrogen Source For Cyanobacteria, Kevin J. Erratt

Electronic Thesis and Dissertation Repository

Urea use has grown substantially in the past half-century, with urea now accounting for > 50% of nitrogen fertilizer applications worldwide. The shift from inorganic nitrogen fertilizers to urea-based sources has coincided with the reappearance of cyanobacteria blooms in freshwaters. Here, we examined urea as a nitrogen source for three bloom-forming cyanobacteria species. We found that (1) urea was consumed more rapidly relative to inorganic nitrogen substrates, suggesting that cyanobacteria exhibit a preference for urea; (2) urea was consumed in excess of cellular requirements; and (3) urea may offer cyanobacteria a competitive edge over eukaryotic algae by enhancing light absorption capabilities. …