Aquatic Sciences Meeting, Albuquerque 2001

PC15 Photochemistry

Date: Thursday, February 15, 2001

Location: Southwest Hall

Zirbel, M, J, Western Washington University/ Shannon Point Marine Center, Anacortes, USA, mjozirbel@hotmail.com

Strom, S, , Western Washington Universtiy/ Shannon Point Marine Center, Anacortes, USA, stroms@cc.wwu.edu

LIGHT-ENHANCED DIGESTION BY MICROZOOPLANKTON

Microzooplankton grazing and growth experiments historically have been conducted in the dark to control for light effects. We hypothesized that light may affect herbivorous microzooplankton metabolism, by causing reactive oxygen species to form in stressed photosynthetic prey cells. Reactive oxygen in grazer food vacuoles may enhance the digestion of algal prey, by breaking down lipid membranes and amino acids. The reactive oxygen probe Dihydrorhodamine-123 indicated higher reactive oxygen concentrations in the heterotrophic dinoflagellate Noctiluca scintillans digesting algae in high light (249 umol photons/sec/m2) compared to Noctiluca digesting in the dark. Experiments were conducted to compare microzooplankton grazing and growth rates in the light and dark. The coupling of irradiance and microzooplankton metabolism would have major implications for our understanding of microbial loop dynamics.

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Aquatic Sciences Meeting, Albuquerque 2001

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