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Marine Ecology Progress Series

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MEPS 444:263-274 (2012)  -  DOI:

Enhancing thermal tolerance by eliminating the pejus range: a comparative study with three ­decapod crustaceans

Jennifer A. Jost1,2, Stephanie M. Podolski1, Markus Frederich1,*

1Department of Marine Sciences, University of New England, Biddeford, Maine 04005, USA
2Present address: Biology Department, Bradley University, Peoria, Illinois 61625, USA

ABSTRACT: Marine invertebrates in the intertidal and subtidal zones are often exposed to highly variable environmental conditions, especially rapid changes in temperature. The ability to survive at different temperatures has previously been described using an extended version of Shelford’s law of tolerance, with optimum, pejus (Latin: ‘turning worse’), and pessimum ranges, and the respective thresholds, critical (Tc) and pejus (T p) temperatures, that mark the transition from one range into the next. The width of the pejus range, in which the scope for activity gradually declines, varies among species. We tested the hypothesis that the width of the pejus range is correlated to the temperature stability of the species’ respective habitats. We used locomotor activity, heart rate, lactate accumulation, heat shock protein 70 (HSP70) levels, and the activation of AMP-activated protein kinase (AMPK) to identify Tc and T p in 3 decapod crustaceans: green crab Carcinus maenas, rock crab Cancer irroratus, and lobster Homarus americanus. We found ­species-specific patterns of temperature-induced changes in all parameters, especially in HSP70 protein and AMPK activity. The width of the pejus range (between T p and Tc) was 8 to 12°C for rock crabs and 12 to 16°C for lobsters. Most importantly, green crab, the most temperature-tolerant of our 3 species and which lives in a highly variable habitat, switched directly from optimum to pessimum range, meaning that the pejus range was eliminated completely. Additionally, even lethal temperatures did not activate AMPK in green crabs, pointing to a different cellular tolerance strategy than in rock crabs and lobsters. This modified tolerance pattern might represent a broader strategy to enhance ­physiological tolerance in a highly variable habitat.

KEY WORDS: AMP-activated protein kinase · AMPK · Heat shock protein 70 · HSP70 · ­Temperature stress · Critical temperatures

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Cite this article as: Jost JA, Podolski SM, Frederich M (2012) Enhancing thermal tolerance by eliminating the pejus range: a comparative study with three ­decapod crustaceans. Mar Ecol Prog Ser 444:263-274.

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