Dobberfuhl, D. R. Arizona State Universtiy, dean.d@asu.edu
Elser, J. R. Arizona State University, j.elser@asu.edu

 
COMMUNITY-LEVEL PATTERNS OF ECOLOGICAL STOICHIOMETRY IN THE LOWER FOOD WEB ACROSS A BROAD LATITUDINAL GRADIENT
 
Considerable variation in the elemental composition of individual species of algae and zooplankton have been recorded. However, the limited amount of existing evidence suggests that, for zooplankton, elemental composition at the bulk community level is uniform and species-level differences are not manifested. Much of the current data come from temperate lakes and it is not known how environmental variables or evolutionary conditions in other regions might affect stoichiometric patterns in the lower food web. To address this question we determined the C:N:P composition of seston and mixed zooplankton communities in lakes in Wisconsin (10 lakes) and Alaska (30 lakes). Zooplankton community C:P ratio was lower in Alaska relative to Wisconsin. Seston C:N ratio was lower while seston N:P ratio was higher in Alaska than in Wisconsin. These data may indicate that arctic zooplankton communities have higher P content, possibly due to growth rate requirements necessary for success in environments with extremely short growing seasons. In contrast, arctic seston appeared to have lower P contents and higher N contents. Thus, elemental imbalance (the difference between resource P content and animal P content) is further accentuated in the arctic lakes relative to the temperate systems. These differences indicate that nutritional constraints on zooplankton may change as a function of latitude.
 
Day: Wednesday, Feb. 3
Time: 02:45 - 03:00pm
Location: Sweeney Center
 
Code: SS49WE0245S