Comments on 'The biology and functional morphology of Arctica islandica' by Brian Morton, Marine Biology Research, 2011

Abstract

In a recent review, Morton (2011, 'The biology and functional morphology of Arctica islandica (Bivalvia: Arcticidae) - A gerontophilic living fossil', Marine Biology Research 7:540-53) provides a detailed description of the function of the anatomy of the long-lived Arctica islandica. In the abstract, Morton concludes that the indolent lifestyle and tissue antioxidant levels sustained into gerontocy predisposes it to negligible senescence and states stable tissue antioxidant levels may slow senescence and extend lifespan. While briefly reviewing only a sub-section of the literature on antioxidants in bivalves, Morton further states that high antioxidant capacities may explain the long lifespan of A. islandica. Recent research demonstrates that such statements are misleading or unsubstantiated. Genetic manipulations of antioxidant expression in a range of species and comparisons of antioxidant activities in longer-lived species compared to shorter-lived relatives produces inconsistent results, but more often elevated antioxidants levels rarely extend lifespan The lack of a clear relationship limits our ability to infer longevity consequences from measures of antioxidant status. In addition, it is outlined why the oxidative stress theory of ageing is severely questioned, if not refuted, and antioxidant capacities of long-lived bivalves do not show such a clear pattern as indicated. © 2012 Copyright Taylor and Francis Group, LLC.