Physiological and biochemical traits correlate with differences in growth rate and temperature adaptation among groups of the eastern oysterCrassostrea virginica

Abstract

SUMMARYWe tested two hypotheses in this study: first, that intraspecific growth variations in a marine bivalve are correlated with physiological (basal metabolic rate and scope for growth) and biochemical (membrane lipids) characteristics, and, second, that this bivalve shows intraspecific variations in physiological and biochemical adaptations to temperature. To test these hypotheses, five genetically distinct groups of juvenile oysters Crassostrea virginica that showed differences in their growth rates were maintained in the laboratory (1) for further measurements of growth and standard metabolic rates and (2) subjected to acclimation at 4°C, 12°C and 20°C and further examined for scope for growth and determination of membrane lipid composition. Our results show that a lower basal metabolic rate and lower unsaturation index of membrane lipids coincides with higher growth rates and a higher scope for growth in oysters. We provide evidence that intraspecific differences in basal metabolic rate in oysters are related to membrane unsaturation as predicted by Hulbertʼs theory of membranes as metabolic pacemakers. Furthermore, our results suggest that the theory of membranes as metabolic pacemakers is related to intraspecific differences in growth. A perfect negative relationship was observed between the acclimation temperature and the unsaturation index of membrane lipids in oysters, as predicted by the homeoviscous adaptation theory. However, changes in the unsaturation index in response to temperature were mainly due to variations in the eicosapentaenoic (20:5n-3) fatty acid in fast-growing oysters, whereas slowgrowing animals changed both docosahexaenoic acid (22:6n-3) and 20:5n-3. Thus, the pattern of biochemical compensation in response to temperature in this species shows intraspecific variation.

Seasonal changes in the behaviour and respiration physiology of the freshwater duck musselAnodonta anatina.

“…On the face of it, bivalves do not appear to compensate oxygen consumption rates at low temperatures, but do partially compensate at intermediate, and in some species, at high temperatures. Evidence for this can be drawn from several marine species, namely Mytilis edulis (Newell and Pye, 1970a;Widdows, 1973), Ostrea edulis (Newell et al, 1977), Crassostrea virginica (Pernet et al, 2007;Pernet et al, 2008), Perna perna (Resgalla et al, 2007), Protothaca thaca (Riascos et al, 2012) and Littorea littorea (Newell and Pye, 1970a). Similar patterns have also been observed in freshwater bivalves, namely Dreissena polymorpha (Alexander and McMahon, 2004) and Amblema plicata (Baker and Hornbach, 2001).…”

“…We are unaware of any data relating the behaviours we studied to temperature change; however, a comparison of previously published data examining the effects of temperature change on oxygen consumption from a range of bivalves is possible. Evidence from a number of marine (Newell and Pye, 1970a;Newell and Pye, 1970b;Widdows, 1973;Newell et al, 1977;Pernet et al, 2007;Resgalla et al, 2007;Pernet et al, 2008;Riascos et al, 2012) and freshwater (Hornbach et al, 1983;Baker and Hornbach, 2001;Alexander and McMahon, 2004) bivalve species indicates that bivalves compensate oxygen consumption rates at intermediate, and in some species, higher temperatures, while there is no evidence of compensation at lower temperatures. As our primary interest was the difference between summer-and winter-acclimatized mussels, we did not measure oxygen consumption rates in Table 1 for a summary of the statistical analysis.…”

Remodeling of membrane lipids in gills of adult hard clam Mercenaria mercenaria during declining temperature

“…Intraspecific variations in membrane lipid remodeling have been reported in hard clams Mercenaria mercenaria and eastern oysters Crassostrea virginica (Pernet et al 2006(Pernet et al , 2008. For example, the phospholipid to sterol ratio in wild hard clams increased transiently with the lowering of temperature, whereas it remained constant in the selectively bred M. mercenaria var.…”

The effect of seasonal temperature variation on behaviour and metabolism in the freshwater mussel (Unio tumidus)

“…In general, oxygen consumption in a range of marine and freshwater bivalves exhibits no thermal compensation at low to intermediate temperatures and only minimal evidence of compensation at intermediate to high temperatures characteristic of their natural thermal range (Alexander and McMahon, 2004;Baker and Hornbach, 2001;Hornbach et al, 1983;Huebner, 1982;Newell et al, 1977;Newell and Pye, 1970;Pernet et al, 2007Pernet et al, , 2008Resgalla et al, 2007;Riascos et al, 2012;Tankersley and Dimock, 1993;Widdows, 1973).…”