ABRUPT CHANGES TO LIMITING FACTORS OF CYANOBACTERIAL BLOOMS IN SUCCESSIVELY DOWNSTREAM LENTIC WATER BODIES

Cyanobacterial blooms in inland waters can degrade water quality and harm human health. Such blooms occur due largely to nutrients delivered allochthonously to a lake or reservoir, but also to additional factors, including fluvial seeding of cyanobacteria, autochthonous sediment release then entrainment of nutrients, and species preference for nutrients (e.g., diazotrophic vs. non-diazotrophic). To assess the impacts of these factors, we monitored the physicochemistry (including nitrogen and phosphorus concentrations) and the life cycles of cyanobacteria within diverse lentic water bodies along the flow direction (drinking water reservoir to throughflow then endorheic lakes along a freshwater to hypersaline gradient) in the Great Salt Lake basin, UT. Results showed that blooms occurred in different patterns despite being located in the same basin with the same regional climate. Blooms were limited by nitrogen at the freshwater reservoir (Phormidiaceae spp. succeeded by Microcystis spp.), phosphorus at the brackish throughflow lake (Aphanizomenon flos-aquae), and inflow at the hypersaline endorheic lake (Nodularia spp.). At the freshwater reservoir, there was a complete shift in the microbial community, from diazotrophic (historically) to non-diazotrophic species (currently), likely due to successful watershed management of phosphorus loading; at the hypersaline endorheic lake, the bay dried up, likely due to high regional water consumption. These results advance knowledge in the proliferation of cyanobacteria and, more broadly, the function of diverse aquatic systems.

Presentation Preference: Oral

Primary Presenter: Raymond Lee, University of Wisconsin-Superior (ramalee420@gmail.com)

Authors:

Raymond Lee, University of Wisconsin-Superior  (rlee26@uwsuper.edu)

Scott Collins, Brigham Young University  (scott@cuwcd.gov)

Erin Jones, Brigham Young University  (erin_jones@byu.edu)

Dylan Dastrup, Brigham Young University  (dylan@cuwcd.gov)

Gabriella Lawson, Brigham Young University  (gmloosle@gmail.com)

Sarah Chan, Brigham Young University  (sarahcp6886@gmail.com)

Rachel Wood, Brigham Young University  (Rachel_wood@byu.edu)

Neil Hansen, Brigham Young University  (neil_hansen@byu.edu)

Benjamin Abbott, Brigham Young University  (benabbott@byu.edu)

Gregory Carling, Brigham Young University  (greg.carling@byu.edu)

Michelle Baker, Utah State University  (mbaker@biology.usu.edu)

Zachary Aanderud, Brigham Young University  (Zachary_aanderud@byu.edu)