"Because they are assumed to live very close to their thermal tolerance limits, organisms inhabiting the rocky intertidal zone have emerged in recent years as potential harbingers of the effects of climate change on species distribution," explain the authors, three of whom are from the University of California, Santa Barbara.
Coauthor Carol Blanchette, a researcher with the Marine Science Institute at the University of California, Santa Barbara, says that neither air nor water temperatures alone are good proxies for body temperatures in intertidal organisms. Multiple climatic factors drive body temperature and the pattern of exposure to these conditions is influenced by shifts in the tidal cycle with latitude.
The researchers put temperature loggers, modified to thermally match living mussels, in mussel beds at eight sites spanning 14 degrees of latitude ranging from northern Washington to Point Conception, Calif. and measured temperatures over the course of a year.
They found that Lompoc Landing, Calif., one of the more southern sites, was thermally very similar to Tatoosh Island, Wash.the northernmost site where instruments were deployed.
In several cases the animals in southern sites are submerged in the afternoon. "As
a result, even if terrestrial climatic conditions become progressively hotter as one moves south along the West Coast, as they likely do, animals at southern sites may be afforded considerable protection by being submerged during the hottest parts of the day," explain the
Contact: Gail Gallessich
University of California - Santa Barbara