THE RESPONSE OF TOXIC FRESHWATER CYANOBACTERIA TO CHANGES IN TEMPERATURE, CO2, AND NITROGEN LIMITATION (E)
Bloom-forming cyanobacteria, particularly toxin-producing species, are recurring with increasing frequency and intensity in aquatic ecosystems, a trend partly related to climate change stressors, particularly a rise in temperature and atmospheric carbon dioxide (CO2) levels. While elevated temperature and CO2 levels enhance growth and other traits in some species, they may suppress them in others. Non-diazotrophic taxa such as Microcystis aeruginosa, for instance, may experience reduced toxin production despite increased cell division rates at higher temperatures, while the impacts of changing temperature and CO2 levels on diazotrophs are poorly understood. It may be hypothesized that nitrogen limitation and elevated CO2 levels select for harmful nitrogen fixing cyanobacteria in freshwater systems relative to non-nitrogen fixers. The purpose of this study is to investigate whether elevated temperature and CO2 levels, as well as nitrogen limitation, affect natural assemblages and cultures of toxic diazotrophic cyanobacteria. Samples collected from New York lakes in the summer of 2016 containing the diazotroph genus Anabaena were shown to exhibit significant increases in nitrogen fixation rates in response to increasing temperature (p < 0.05; 20 – 30oC). The effects of temperature and CO2 levels as well as nitrogen limitation on the growth, nitrogen fixation rate, and anatoxin-a content of several Anabaena strains will also be investigated.
Kramer, B. J., Stony Brook University, USA, firstname.lastname@example.org
Gobler, C. J., Stony Brook University, USA, email@example.com
Time: 11:00 - 12:00
Location: Poster/Exhibit Hall
Presentation is given by student: Yes