Abstract


THE EFFECT OF TEMPERATURE ON NITROGEN FIXATION IN NOSTOC SPECIES IN STREAMS IN THE HENGILL REGION OF ICELAND

Nitrogen-fixing cyanobacteria play an important role in nutrient dynamics in freshwater ecosystems, yet it is unclear how various taxa will respond to climate warming. To explore the response of three different Nostoc species to changing temperature, we conducted transplant experiments across a naturally-occurring stream temperature gradient in the Hengill region of Iceland, in streams ranging from 5-20 ˚C. Each species occurs at a different temperature range from cold streams, dominated by Nostoc pruniforme (5-8 ˚C), intermediate temperatures occupied by Nostoc spongiaeforme (8-12 ˚C), and Nostoc amplissimum, found in warmer streams (12-18 ˚C). N2-fixation measurements were made 24-h after transplant using in situ acetylene reduction assays in both resident and transplant locations (n=5). There was a significant positive relationship between N2-fixation rate and temperature across transplant locations in Nostoc spongiaeforme (R2=0.92, p<0.01), while there was no significant difference in N2-fixation rate in Nostoc amplissiumum or Nostoc pruniforme across the temperature gradient. Results indicate that acclimation to temperature is variable across taxa and species-specific responses will influence how much nitrogen is supplied to freshwater ecosystems, influencing productivity and food web dynamics.

Authors

Ahles, A. M., St. Catherine University, USA, amahles@stkate.edu

Welter, J. R., St. Catherine University, USA, jrwelter@stkate.edu

Goldschmidt, J. B., St. Catherine University, USA, jbgoldschmidt@stkate.edu

Sander, D. R., St. Catherine University, USA, drsander@stkate.edu

Furey, P. C., St. Catherine University, USA, pcfurey@hotmail.com

Details

Poster presentation

Session #:024
Date: 5/22/2014
Time: 18:00 - 20:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 106