CS39A Zooplankton - Feeding, Reproduction, Growth and Molecular Diversity
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
SpeekmannCL, University of Texas at Austin, Marine Science Institute, Port Aransas, USA, christa@utmsi.utexas.edu
Buskey, E, J, University of Texas at Austin, Marine Science Institute, Port Aransas, USA, buskey@utmsi.utexas.edu
 
ASSESSING THE HEALTH OF PLANKTONIC FOOD WEBS USING RNA:DNA RATIOS
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Marine copepods are normally the dominant zooplankton taxa and are an important link in the food web between phytoplankton and larval fish. Evaluating the vigor of copepod populations in nature can be attempted by measuring growth or egg production rates, but these methods involve tedious experiments with long incubation times. RNA:DNA ratios have been used to describe growth and nutritional conditions of field collected copepods, but the standard ethidium bromide method requires pooling of 10 small copepods, sacrificing measures of individual variability. Using new fluorescent dyes to detect RNA and DNA, ratios can be determined for a single small copepod. Both methods are based on the assumption DNA per somatic cell is constant in adults, while the amount of RNA is positively correlated with protein synthesis. We will report the results of laboratory experiments measuring the effect of nutrition on egg production, RNA content and RNA:DNA ratios of individual adult female Acartia tonsa. We hope to apply the results of this study to field collected A. tonsa, to asses the health of the planktonic food wed in local bays.