HALPIN, P. M. : The effect of tide height, season, and water column productivity on the heat shock response in intertidal organisms

Intertidal organisms experience stress along a range of temporal and spatial scales. Ecologists and physiologists are currently being challenged to identify ecologically relevant physiological processes and their impact on biological communities. Here we examine both physiological and ecological parameters taken across spatial scales of meters (vertical intertidal zonation) and kilometers in the context of heat stress and the production of heat shock proteins (hsp). Intertidal organisms may experience temperature changes over a 20C range as they are emersed and immersed by the tides. We examine several field studies on how biotic interactions and physiological responses change across physical stress gradients, focusing on the heat shock response in two types of intertidal organisms, sessile filter feeders and mobile herbivores at sites that differ in their concentrations of water column Chl-a and thermal regimes. Results indicate strong temporal and spatial variation in expression of stress proteins at both the small scale (e.g. months and meters) and large scale (e.g. seasons and kilometers). Results also indicate that organisms respond to a suite of environmental variables which must be understood to predict the response of populations and communities to environmental change.