Meeting Abstract
High temperatures during low tide periods are typically viewed as a potential detriment to the energy budget and survival of intertidal organisms. Because most marine organisms stop feeding or curtail photosynthesis during aerial exposure, there is no immediate opportunity to offset increasing metabolic demands by increasing energy intake while warm, such that faster metabolic rates and the induction of heat shock responses could lower the scope for growth. Using a novel manipulation of substratum temperature conditions during low tide, we tracked densities of microalgal food resources and growth rates of herbivorous limpets over several months at our central California field site. In contrast to our expectations, when low tide temperature conditions were warm but not close to limpets’ lethal limits, we found evidence of increased growth rates in warmer microhabitats provided that sufficient food was available for feeding during high tide. Limpets in warmer microhabitats may be able to exploit warm low tide conditions to increase rates of both catabolic and anabolic processes, and may increase subsequent grazing effort during high tide to accommodate their higher metabolic rates in warm microsites. In view of the increases in average global temperature projected for the coming decades, small increases in air temperature as the climate warms may initially increase energy transfer through this simple trophic chain and increase the top-down control on microalgal communities by grazing limpets.
