Aquatic Sciences Meeting, Albuquerque 2001

SS19 Revisiting Redfield: C:N:P Stoichiometry in Aquatic Ecosystems (Disciplinary Connections)

Date: Tuesday, February 13, 2001, Time: 12:15:00 PM

Location: Acoma/Zuni/Tesuque

Elser, J, J, Arizona State University, Tempe, AZ, USA, j.elser@asu.edu

Kyle, M, , Arizona State University, Tempe, AZ, USA,

Yoshida, T, , Kyoto University, Kyoto, Japan,

Makino, W, , University of Minnesota, St. Paul, MN, USA,

Andersen, T, , Norwegian Institute for Water Research, Oslo, USA,

Urabe, J, , Kyoto University, Kyoto, USA,

REDUCED LIGHT INCREASES HERBIVORE PRODUCTION DUE TO STOICHIOMETRIC EFFECTS OF LIGHT:NUTRIENT BALANCE.

Ecological common sense says that decreased solar energy should reduce herbivore production because of reduced energy flow through primary producers. However, a field experiment in a phosphorus-limited lake showed that production of zooplankton herbivores was increased by shading. This paradoxical outcome was caused by a decoupling of producer carbon fixation and nutrient uptake under high light that reduced food quality for herbivores. At low nutrient supplies, shading increased nutrient contents relative to carbon within algal food, outweighing effects of decreased primary production. Thus, light:nutrient balance affects the degree of mismatch between primary producers and herbivores in nature, which in turn influences mass transfer efficiencies along food chains. To predict how energy transfer efficiency and biological interactions will respond to perturbations, it is essential to take into account changes in light:nutrient balance and its effects on the stoichiometry of autotroph - herbivore interactions.

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Aquatic Sciences Meeting, Albuquerque 2001

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