QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online September 11, 2009
Journal of Experimental Biology 212, 3051-3059 (2009)
Published by The Company of Biologists 2009
doi: 10.1242/jeb.031401

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Sperfeld, E. Articles by Wacker, A. PubMed PubMed Citation Articles by Sperfeld, E. Articles by Wacker, A. Social Bookmarking                         What's this?

Effects of temperature and dietary sterol availability on growth and cholesterol allocation of the aquatic keystone species Daphnia

Erik Sperfeld^* and Alexander Wacker

Department of Theoretical Aquatic Ecology, Institute of Biochemistry and Biology, University of Potsdam, Am Neuen Palais 10, D 14469 Potsdam, Germany

^* Author for correspondence (eriksperfeld{at}googlemail.com)

Accepted 30 June 2009

Enhanced water temperatures promote the occurrence of cyanobacterial blooms, which may be detrimental to aquatic herbivores. Especially, the often-dominant crustaceans could be negatively affected because cyanobacteria are deficient in phytosterols, which are required by the crustaceans to form the membrane component cholesterol, which in turn plays a role in thermal adaptation. Here, we determined the influence of temperature on growth, reproduction and the allocation of dietary sterol into somatic tissues and eggs of the keystone species Daphnia magna raised along a dietary cholesterol gradient. Mass-specific growth rates of D. magna increased with the increasing availability of dietary cholesterol up to an incipient limiting level, which increased with increasing temperature. This indicates a higher demand for cholesterol for growth at higher temperatures and may explain the consistently smaller clutch sizes of reproducing females at the highest temperature. The cholesterol content of the individuals increased with increasing dietary cholesterol; this increase was enhanced at higher temperatures, indicating a higher demand for cholesterol for tissues and probably specifically for membranes. Surprisingly, the daphnids showed different allocation strategies with regard to temperature and dietary sterol availability. The cholesterol content of eggs was enhanced at higher temperature, which suggested that females allocate more cholesterol to their offspring, presumably to ensure sufficient egg development. When dietary cholesterol was limiting, however, females did not allocate more cholesterol to their eggs. Our data suggest that during cyanobacterial blooms, a potential dietary sterol limitation of Daphnia can be intensified at higher water temperatures, which can occur with global warming.

Key words: allocation strategy, cholesterol, growth, reproduction, temperature adaptation, zooplankton

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?