title: Micro-scale environmental variation amplifies physiological variation among individual mussels.
abstract: The contributions of temporal and spatial environmental variation to physiological variation remain poorly resolved. Rocky intertidal zone populations are subjected to thermal variation over the tidal cycle, superimposed with micro-scale variation in individuals' body temperatures. Using the sea mussel (Mytilus californianus), we assessed the consequences of this micro-scale environmental variation for physiological variation among individuals, first by examining the latter in field-acclimatized animals, second by abolishing micro-scale environmental variation via common garden acclimation, and third by restoring this variation using a reciprocal outplant approach. Common garden acclimation reduced the magnitude of variation in tissue-level antioxidant capacities by approximately 30% among mussels from a wave-protected (warm) site, but it had no effect on antioxidant variation among mussels from a wave-exposed (cool) site. The field-acclimatized level of antioxidant variation was restored only when protected-site mussels were outplanted to a high, thermally stressful site. Variation in organismal oxygen consumption rates reflected antioxidant patterns, decreasing dramatically among protected-site mussels after common gardening. These results suggest a highly plastic relationship between individuals' genotypes and their physiological phenotypes that depends on recent environmental experience. Corresponding context-dependent changes in the physiological mean-variance relationships within populations complicate prediction of responses to shifts in environmental variability that are anticipated with global change.
authors.affiliation: Department of Biology, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.
authors.forename: Ana Gabriela
authors.initials: AG
authors.lastname: Jimenez
authors.affiliation: Department of Chemistry and Biochemistry, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.
authors.forename: Sarah
authors.initials: S
authors.lastname: Jayawardene
authors.affiliation: Department of Chemistry and Biochemistry, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.
authors.forename: Shaina
authors.initials: S
authors.lastname: Alves
authors.affiliation: Department of Biology, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045.
authors.forename: Jeremiah
authors.initials: J
authors.lastname: Dallmer
authors.affiliation: Department of Biology, Loyola Marymount University, 1 LMU Drive, Los Angeles, CA 90045 wdowd@lmu.edu.
authors.forename: W Wesley
authors.initials: WW
authors.lastname: Dowd
mesh_terms: D000064:Acclimatization / Q000502:physiology; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001831:Body Temperature; D002374:Catalase / Q000378:metabolism; D004777:Environment; D006358:Hot Temperature; D009132:Muscles / Q000201:enzymology; D049878:Mytilus / Q000502:physiology*; D025341:Principal Component Analysis; D055871:Tidal Waves
chemical_list: D000975:Antioxidants; D002374:Catalase
keywords: antioxidant; inter-individual variation; intertidal zone; metabolic rate; physiological plasticity; temperature