Aquatic Sciences Meeting, Albuquerque 2001

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

Date: Tuesday, February 13, 2001, Time: 4:00:00 PM

Location: Acoma/Zuni/Tesuque

Frost, P, C, Arizona State University, Department of Biology, Tempe, USA, pcfrost@asu.edu

Elser, J, J, Arizona State University, Department of Biology, Tempe, USA, j.elser@asu.edu

POOR ELEMENTAL FOOD QUALITY AFFECTS MAYFLY GROWTH

One well-studied area in ecological stoichiometry is that of food quality effects on animal growth. High C:P ratios in organic matter are common in littoral zones and consequently, growth of benthic grazers could be limited by the P content of their food. We tested this hypothesis with growth experiments using littoral mayflies. In a laboratory experiment, we provided mayflies (Caenis sp.) with monoculture algae having different C:P ratios (high C:P ~650, low C:P ~80). Mayflies given high C:P food did not grow whereas low C:P food resulted in significantly higher and positive growth rates. We repeated this experiment at the Experimental Lakes Area, Canada using mayflies (Ephemerella sp.) grown on natural organic matter. In these experiments, mayfly growth rates were highest in the naturally low C:P (~330) food. P-enriched food (C:P ~50) yielded significantly higher growth compared to unenriched naturally high C:P (~550) food collected from the same lake. Our results demonstrate that mayflies grow slower when consuming food with high C:P ratios and indicate that littoral zone food webs are strongly affected by elemental imbalances at the grazer-producer interface.

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Aquatic Sciences Meeting, Albuquerque 2001

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