FITZHENRY, T.M; PODOLSKY, B.E.; Univ. of North Carolina; Univ. of North Carolina: Consequences of site selection, temperature stress and its effects on reproductive success in Chthamalus fragilis

Temperature stress is an important factor in the distribution and physiological performance of intertidal organisms. The exact location of an organism, including its orientation, tidal height, and surrounding surfaces, will directly affect the amount of temperature stress experienced by that organism. For a sessile organism settlement site will therefore play a large role in its future environmental exposure. Increased exposure to temperature stress can lead to loss of reproductive output. In brooding intertidal organisms, temperature stress has the potential to affect not only future reproductive output but also currently brooded offspring. The brood�s fitness may decrease due to high temperatures. To address the effects of temperature stress on reproductive success, I am studying the intertidal barnacle Chthamalus fragilis, which can be exposed to high temperatures during low tides. C. fragilis inhabits the upper intertidal zone which other barnacles, mainly Balanus sp., are excluded due to their heat intolerance. It has been shown that Chthamalus sp brood during the hot summer months and are capable of producing multiple broods per year. During high temperature events C. fragilis produces heat shock proteins (Hsps) that allow for the recovery of heat-denatured proteins. This response however, can be energetically costly, and the effects of C. fragilis Hsp production on reproductive output and brooded offspring are unknown. In this study I am testing the temperature conditions under which C. fragilis induced to express Hsp70 and the maximum temperature from which C. fragilis can recover. These results will be the foundation for future work examining the effects of temperature stress on reproductive success.