Saros, J. E. Lehigh University, jeg7@lehigh.edu
Fritz, S. E. University of Nebraska,

 
CHANGES IN THE OUTCOME OF NUTRIENT COMPETITION BETWEEN SALINE-LAKE DIATOMS IN RESPONSE TO VARIATION IN N:P RATIOS, SALINITY, AND BRINE TYPE
 
Diatom stratigraphies in closed-basin lake sediments are commonly used to reconstruct climate change based on the observation that diatom species distributions are highly correlated with salinity and anion composition. Although strong correlations exist, the actual mechanisms behind these correlations are unknown. Both salinity and anion composition have an impact on nutrient dynamics in saline systems, hence nutrients may serve as a mechanistic link between diatom community structure and ionic concentration/composition. To provide insight into the basis of these correlations, we tested the effect of salinity (5, 8, and 11 ) and brine type (sulfate vs. bicarbonate) on the outcome of nutrient competition between 4 diatom taxa. A suite of N:P ratios was used, as the cycling of these nutrients typically differs between sulfate and bicarbonate systems. In general, we found that Chaetoceros elmorei fared well under all conditions, whereas Cyclotella quillensis biomass declined at high N:P ratios. Cymbella pusilla was more abundant at low N:P ratios, particularly in the 5 bicarbonate treatments. Anomoneis costata declined under all conditions.
 
Day: Thursday, Feb. 4
Time: 09:15 - 09:30am
Location: Sweeney Center
 
Code: CS62TH0915S