The sensitivity of the early benthic juvenile stage of the European lobster Homarus gammarus (L.) to elevated pCO2 and temperature

The early benthic juvenile stage of many marine invertebrates is a key step in the transition from the planktonic larval stages to the benthic adult stage. It is characterised by high mortality, in part, due to sensitivities to abiotic factors. The impacts of elevated p CO 2 and temperature on the physiology and life history of these sensitive life stages are, however, poorly understood. Consequently, the aim of the present study was to investigate the vulnerability of survival, growth, metabolic rate, feeding rate, organic content, and carapace mineralisation of the early benthic juvenile stage of the European lobster Homarus gammarus (L.) to predicted levels of elevated p CO 2 [ocean acidification (OA) and carbon capture and storage (CCS) scenarios] and elevated temperature [ocean warming (OW)]. Early benthic juvenile H. gammarus exhibited increased mortality under both OA and CCS conditions at both experimental temperatures, and these mortalities were due to moult death syndrome. There were OA-related reductions in metabolism, food acquisition, and carapace mineral content, while CCS-exposed lobsters exhibited severe shell dissolution. We suggest that disruption of metabolic and calcium homoeostasis is associated with, and possible the cause of, the increased incidence of moult-related mortalities in juvenile lobsters. We conclude that early benthic juvenile lobsters are sensitive, in terms of physiology and life history traits, to both OA and CCS, with OW sometimes mitigating and at other times increasing sensitivities.