The Impacts of Acidification and Warming on the Growth and Metabolism of Juvenile Blue Crab (Callinectes sapidus) from the Patuxent River, Chesapeake Bay

Future climate scenarios predict increases in both oceanic temperature and dissolved carbon dioxide (CO₂) over the next century.  Calcifying invertebrates, which depend on specific conditions of temperature and carbonate chemistry for many biological processes, may be especially impacted by these climate changes.  Here we report the results of a study on the combined effects of increased water temperature and CO₂ on the growth and metabolism of juvenile blue crab, Callinectes sapidus.  Crabs were kept individually in one of four temperature/CO₂ treatments (ambient/ambient, ambient /high, high/ambient, high /high) for two complete molts.  The growth per molt (GPM) and intermolt period (IMP) were quantified for each crab and analyzed by temperature/CO₂ treatment.  After exposure, respiration was determined by measuring oxygen consumption of crabs in closed chambers with a fiber-optic oxygen electrode.  GPM and IMP were not impacted by the combined effects of increased temperature and CO₂ (P>0.05).  However, temperature and CO₂ imposed a synergistic effect on crab respiration.  Respiration of crabs in the high temperature/high CO₂ treatment was significantly higher than the respiration of crabs in all other treatments (P<0.05).  These data imply that there may be an increased energetic cost for crabs living in the climate conditions of the future.