Meeting Abstract

46.1  Saturday, Jan. 5  Small-scale spatial and temporal variation in metabolic and antioxidant enzyme capacities within a population of rocky intertidal mussels (Mytilus californianus) DOWD, W.W.*; FELTON, C.; HEYMANN, H.M.; KOST, L.E.; SOMERO, G.N.; Loyola Marymount University; Hopkins Marine Station of Stanford University; Hopkins Marine Station of Stanford University; Hopkins Marine Station of Stanford University; Hopkins Marine Station of Stanford University wdowd@lmu.edu

Denizens of wave-exposed, rocky intertidal shores inhabit a spatially complex and dynamic environment, characterized by rhythmic and/or stochastic exposures to both environmental (e.g., emersion, desiccation, temperature extremes) and biological challenges (e.g., predation, competition, food availability). Much effort has been devoted to studying patterns of physiological and/or genetic variation within and between such species, along latitudinal, vertical, seasonal or other relatively large scales. More recently, attention has been focused on small-scale, intra-population variation in physiology and the factors that might regulate it. For example, other work has documented temporal variation in gene expression in the intertidal mussel Mytilus californianus over the course of tidal cycles. In the present study, we approached this issue of intra-population variation from a functional perspective. We quantified temporal changes (over a 5-d period) in biochemical capacities for ATP generation (citrate synthase and malate dehydrogenase) and antioxidant defense (catalase and superoxide dismutase) in mussels from four different micro-sites separated in space by short distances. The patterns of temporal variation varied among micro-sites, but overall metabolic and antioxidant capacities were strongly correlated. We then examined candidate environmental factors that might contribute to spatial and temporal variation in physiology, including variation in emersion time, thermal history, or food abundance. Our results implicate a complex suite of interacting factors that influence the biochemical state of intertidal mussels.