Schulz, K. L. University of Minnesota,
Sterner, R. W. University of Minnesota,
Hessen, D. O. University of Oslo,
Elser, J. J. Arizona State University,

Most work on zooplankton community composition has focussed on predation, both invertebrate and vertebrate, as the primary or sole structuring force. However, zooplankton nutritional requirements may result in 'zones of exclusion': areas where certain species can not exist, despite apparently optimal environmental and predatory conditions. Recent laboratory work demonstrates that Daphnia, a zooplankton species with a high phosphorous (P) content, requires a high concentration of phosphorus in its food to maintain adequate nutrition. Zooplankton with lower P contents, such as Bosmina and Diaphanosoma, do not seem to require large amounts of P. In addition to these laboratory findings, we predict that because many copepod nauplii possess a high P content, they will also be constrained by the amount of P in their food. These experimental and stoichiometric data allow us to predict quantitatively 'zones of exclusion' in which organisms such as Daphnia and some nauplii would receive inadequate nutrition for population growth due to low P content of the available food. How real are these nutritional exclusion zones? The predicted P constraints will be tested with a large data set containing hundreds of seston and zooplankton observations from many North American and Norwegian lakes and reservoirs to determine the strength of P nutritional constraints in nature.
Day: Wednesday, Feb. 3
Time: 09:15 - 09:30am
Location: Hilton of Santa Fe
Code: SS21WE0915H