NITROGEN FIXATION AND TOXIN PRODUCTION IN APHANIZOMENON FLOS-AQUAE UNDER VARIABLE N:P:FE STOICHIOMETRY

Current research indicates that free nitrate and iron concentrations in waterbodies impact nitrogen fixation as well as cyanotoxin production in cyanobacteria species. The purpose of this experiment was to analyze the effects of nitrogen addition through stoichiometric relationships with respect to iron and phosphorus levels in Aphanizomenon flos-aquae PCC 7905[TH1] . Because Aphanizomenon flos-aquae is a diazotrophic species, we hypothesized that we would observe a tradeoff in which the samples grown in low nitrogen conditions would decrease in toxin production[TH2]  and increase in nitrogen fixation. We tested this hypothesis with a laboratory experiment where we manipulated N:P treatments of 1, 5, 10, 20, and 50 at low iron and high iron concentrations. Gene expression encoding for both toxin production and nitrogen fixation were measured using qPCR following a 28-day experiment and subsequent 48-hr modification. Preliminary data indicated that N fixation may have offset N deficiency and elevated biomass in low N treatments. We will show data on the biomass, stoichiometry, and gene expression rates from our final sample analysis.  

Primary Presenter: Sara Coppellotti, Baylor University (sara_coppellotti1@baylor.edu)

Authors:

Sara Coppellotti, Baylor University  (sara_coppellotti1@baylor.edu)

Abby Smason, Baylor University  (Abby_Smason1@baylor.edu)

Hope Tucker, Baylor University  (Hope_Tucker1@baylor.edu)

Amelia Mullis, Baylor University  (Amelia_Mullis1@baylor.edu)

Zach Bass, Baylor University  (zach_bass2@baylor.edu)

Ruth Deffenbaugh, Baylor University  (ruth_deffenbaugh1@baylor.edu)

Loren Preisler, Baylor University  (Loren_Preisler1@baylor.edu)

Kirsten Schatz, Baylor University  (Kirsten_Shatz1@baylor.edu)

Hali Temkin, Baylor University  (Hali_Temkin1@baylor.edu)

Epiphany Velasco, Baylor University  (Epiphany_Velasco1@baylor.edu)

Victoria Whelan, Baylor University  (Victoria_Whelan1@baylor.edu)

Jaqcuelyn Duke, Baylor University  (jacquelyn_duke@baylor.edu)

Katelyn McKindles, Baylor University  (Katelyn_McKindles@baylor.edu)

Thad Scott, Baylor University  (Thad_Scott@baylor.edu)