Patterns of variation in levels of Hsp70 in natural rocky shore populations from microscales to mesoscales

An important step in connecting the organismal response to thermal stress to patterns of community structure is determining at what scale discernable levels of variation are manifested. The temperature signal to which organisms may potentially respond varies at many spatial scales including microhabitat, tidal height, site and latitude. A number of studies have taken physiological assessment of the heat shock response (HSR) into the intertidal both as a tool for examining the HSR in nature and for examining the utility of HSR molecules as population or community level indicators. Most commonly, immunodetection of the total pool of the Hsp70 family of isoforms is used. Here we present data on levels of Hsp70 in intertidal organisms from microhabitat to the mesoscale. Our data and previously published work show that Hsp70 levels vary at all scales examined, similar to other physical and biological variables of interest. This demonstrates both the potential utility of Hsp70 detection as a molecular tool for field biologists and to the care that must be taken in assessing scale of variation when looking for potential bioindicator molecules.