Variation in the sensitivity of organismal body temperature to climate change over local and geographic scales

doi:10.1073/pnas.0510992103

Variation in the sensitivity of organismal body temperature to climate change over local and geographic scales

Department of Biological Sciences, University of South Carolina, Columbia, SC 29208

Edited by Christopher B. Field, Carnegie Institution of Washington, Stanford, CA, and approved May 8, 2006 (received for review December 21, 2005)

Abstract

Global climate change is expected to have broad ecological consequences for species and communities. Attempts to forecast these consequences usually assume that changes in air or water temperature will translate into equivalent changes in a species’ organismal body temperature. This simple change is unlikely because an organism’s body temperature is determined by a complex series of interactions between the organism and its environment. Using a biophysical model, validated with 5 years of field observations, we examined the relationship between environmental temperature change and body temperature of the intertidal mussel Mytilus californianus over 1,600 km of its geographic distribution. We found that at all locations examined simulated changes in air or water temperature always produced less than equivalent changes in the daily maximum mussel body temperature. Moreover, the magnitude of body temperature change was highly variable, both within and among locations. A simulated 1°C increase in air or water temperature raised the maximum monthly average of daily body temperature maxima by 0.07–0.92°C, depending on the geographic location, vertical position, and temperature variable. We combined these sensitivities with predicted climate change for 2100 and calculated increases in monthly average maximum body temperature of 0.97–4.12°C, depending on location and climate change scenario. Thus geographic variation in body temperature sensitivity can modulate species’ experiences of climate change and must be considered when predicting the biological consequences of climate change.

Footnotes

*To whom correspondence should be sent at the present address:
Friday Harbor Laboratories, University of Washington, 620 University Road, Friday Harbor, WA 98250.
E-mail: gilmans{at}u.washington.edu
Author contributions: S.E.G., D.S.W., and B.H. designed research; S.E.G., D.S.W., and B.H. performed research; D.S.W. contributed new reagents/analytic tools.; S.E.G. analyzed data; and S.E.G., D.S.W., and B.H. wrote the paper.
Conflict of interest statement: No conflicts declared.
This paper was submitted directly (Track II) to the PNAS office.
Abbreviations:

Abbreviations:

DBTM,

daily body temperature maximum;

BTS,

body temperature sensitivity;

Tw,

water temperature;

Ta,

air temperature;

Ts,

surface temperature;

SRES,

Special Report on Emission Scenarios.