They wanted to find out if snails continue to manufacture proteins in their cells when exposed to high temperatures.
Somero and Tomanek compared two snail species commonly found in Monterey Bay. One type, Tegula funebralis, lives near the surface and frequently is exposed to full sun during low tide. The other, T. brunnea, usually is submerged and therefore experiences less intense heat during the day.
When kept at a temperature of 86 F (30 C) for 2.5 hours, T. funebralis continued to manufacture proteins - unlike its cousin, T. brunnea, which virtually stopped all protein production and eventually died.
``These data help to explain the different vertical distribution of these two species of Tegula,`` notes Somero. ``The lower-occurring species, T. brunnea, simply cannot continue to manufacture proteins at temperatures routinely experienced by its higher-occurring cousin, T. funebralis.
``But even T. funebralis is poised near its thermal tolerance limit for protein synthesis,`` he concludes, ``and if an organism can no longer make proteins - the molecules responsible for metabolism - then its survival is in jeopardy. Therefore, additional warming could create serious problems for both snail species.``
These experiments may help to explain why so many marine invertebrates, once common in Monterey Bay, have become less abundant there.
``It appears that some species are at the upper boundary of their thermal tolerance range,`` says Somero, ``so higher ocean temperatures may force them to seek out cooler pastures.``
And even if these displaced species avoid extinction by moving to cooler regions, their disappearance could significantly perturb the ecosystem, he maintains.