INTERACTIVE EFFECTS OF TEMPERATURE, NITROGEN FORM, AND N:P STOICHIOMETRY ON THE ELEMENTAL COMPOSITION AND ECO-PHYSIOLOGY OF MICROCYSTIS

Cyanobacteria blooms are increasing in frequency, intensity, and duration globally. Major drivers of cyanobacterial bloom formation include the concentration of nitrogen (N) and phosphorus (P), the N:P stoichiometry, temperature, water column stability, and light. Although the drivers of bloom formation are known, predicting bloom formation, size, and cyanotoxin potential remains elusive. One potential research area that has received little attention is how the elemental composition changes beyond carbon, N, and P, particularly with different N forms and across temperature gradients that may provide insights into bloom formation and expansion. Here, we examined how temperature, nitrogen form, and supply N:P affect the ionome (i.e., elemental composition beyond carbon, N, and P) and eco-physiological traits of Microcystis aeruginosa (LE3). We grew quadruplicates consisting of nitrate or urea as the N-form, at a N:P of 2, 16, 30, and 50, and across a four-temperature gradient ranging from 20 to 32 degrees Celsius and measured the volume corrected, cell quotas, and biovolume of the ionome, and chlorophyll a. We found numerous two-way and three-way interactions among the N:P supply, N-form, and temperature. The ionomic composition was affected by N:P supply, N-form, and temperature. Overall, our results highlight the interconnectedness of the ionomic composition within and among N:P supply and N-form and, when incorporated into a predictive framework, may be better at predicting bloom size and toxin potential. 

Primary Presenter: Nicole Wagner, Oakland University (nicolegouldingwagner@gmail.com)

Authors:

Nicole Wagner, Oakland University  (nicolewagner@oakland.edu)

Tessa Wallace, Oakland University  (tvwallace@oakland.edu)

Olivia Sowa, Oakland University  (oliviasowa@oakland.edu)

Ryan Andrews, Oakland University  (ryanandrews@oakland.edu)

Clay Prater, University of Arkansas  (prater.clay@gmail.com)