The effects of elevated temperature and pCO2 on the developmental eco-physiology of the European lobster, Homarus gammarus (L.)

The successful completion of the early developmental stages in organisms with complex life cycles is crucial to the persistence of a species both at the local and global scale. Thus changes in the abiotic environment experienced during larval and early benthic development can have profound effects on the development and ultimately dynamics of populations of marine invertebrates. The effects of elevated temperature and pCO2 in line with future predictions of anthropogenic climate change, ocean warming and ocean acidification (OA), on the survivorship and growth during early development of marine invertebrates is beginning to be understood, yet the underlying physiological ontogeny driving such changes, and the more subtle effects on physiological performance of climate change drivers, has yet to be distinguished. Therefore the aim of the present study is to investigate the effects of elevated temperature and pCO2 on the developmental eco-physiology of an economically and ecologically important species, the European lobster, Homarus gammarus, to characterise the underlying physiological responses of early development behind responses of survival and growth. The main findings relate to how changing optimal temperature conditions during larval development results in changes in metabolic performance and therefore aerobic scope, ultimately driving survival and growth. Larval stages which exhibit narrower aerobic scope were also sensitive to elevated pCO2 evident as reduced survival, changes to energetic demands and organic content, and reduced calcification. Furthermore, this is the first attempt to characterise the physiological response of early benthic juveniles to climate change drivers. Early benthic juveniles are quite different in underlying physiology to later juveniles and adults, cumulating in this stage being energy limited. Such limitations are expressed as a reduction in aerobic scope in relation to elevated temperature and pCO2, and associated sensitiveness to elevated pCO2 resulting in increased moult related mortalities and the breakdown of haemolymph buffering capacity under combinations of elevated temperature and pCO2. Throughout early development, elevated temperature and pCO2, through underlying physiological responses, may have dramatic effects on the geographic range and successful development of H. gammarus.Plymouth Marine Laboratory, National Lobster Hatchery, National Marine Aquariu