PARENT SESSION
Symposium #33: The ecology and evolution of coupled energy and material flows: integration of multiple scales and multiple biota.

Organized by: JD Schade, T Markow, and S Hobbie
Friday, August 9. 9:00 AM to 12:00 PM. Crystal Ballroom, TCC.

Seston stoichiometry at the regional scale: What is the mean and variance of C:N:P of the average lake?

STERNER, ROBERT^*,1, ELSER, JAMES², HENDRIXSON, HEATHER¹, ¹ University of Minnesota, St. Paul, MN² Arizona State University, Tempe, AZ

ABSTRACT- The C:P and C:N ratios of particulate matter (seston) in lakes is known to vary both in time and space. Here we combine newly collected data on the seston chemistry of 128 lakes of the Upper Midwest (So. and No. Dakota, Iowa, Minnesota, and Michigan) with previously analyzed data from Ontario and Michigan to create a dataset with seston chemistry for more than 150 lakes in this region. We use this data to address the question of what is a "typical" stoichiometry for seston for lakes in this region, as well as what the stoichiometric variation looks like. The mean C:P ratio (330) is similar to values previously suggested to indicate a transition between C and P limitation in some zooplankton. We also partition variation regionally; we found that lakes of northwest Ontario (the Experimental Lakes Area) have generally higher C:P ratios than other lakes. Furthermore, we find big differences in seston C:P ratios between stratified and shallow, unstratified lakes, particularly at high fertility.

KEY WORDS: stoichiometry, plankton, phosphorus, lake