P3.46 Friday, Jan. 6 Hawaiian littoral gastropods’ heated existence. COCKETT, P.M.*; NEDVED, B.T.; HADFIELD, M.G.; Univ. of Hawaii, Manoa; Univ. of Hawaii, Manoa; Univ. of Hawaii, Manoa email@example.com
Organisms that live within the littoral zone of Hawaii must tolerate extreme environmental stressors. In mid-summer, temperatures experienced by littoral organisms in a single tidal cycle range from 25° to 45°C. Other studies have shown that the expression of heat shock proteins (HSP) in gastropods occupying the highest portions of the temperate littoral zone is constituitive, while the HSPs of snails living closer to mean low tide are induced by increasing temperatures. The Intergovernmental Panel on Climate Change (IPCC) predicts that average surface temperatures will increase between 2° and 6°C by the end of the 21st century. This is cause for concern if the littoral gastropods are already living at or near their thermal limits. Thermal tolerances and vertical distributions were examined for four intertidal gastropods in Hawaii: Littoraria pintado, Siphonaria normalis, Nerita picea, and Morula granulata. These four gastropods occupy niches that extend from the uppermost portions of the littoral zone to mean low tide. Field surveys undertaken to determine the vertical distributions of these snails revealed significant differences in mean height among the four species, and temperatures of the rocks adjacent to the snails (collected with iButton® temperature loggers) showed significant differences among the snail habitats. Lethal temperatures for the four gastropods were determined in the laboratory and compared to the temperatures they experience in the field; resulting data confirmed that each species lives close to its uppermost thermal limit. Currently we are attempting to quantify HSP expression in each of the gastropod species using western blotting techniques.