The effect of CO2 acidified sea water and reduced salinity on aspects of the embryonic development of the amphipod Echinogammarus marinus (Leach)

We investigated the effect of CO2 acidified sea water (S = 35, 22 and 10PSU) on embryonic development of the intertidal amphipod Echinogammarus marinus (Leach). Low pH, but not low salinity (22PSU), resulted in a more protracted embryonic development in situ although the effect was only evident at low salinity. However reduced salinity, not pH, exerted a strong significant effect, on numbers and calcium content of hatchlings. Females exposed to low salinity (10PSU) did not carry eggs through to hatching. There was no significant difference in the number of viable hatchlings between females cultured in 22 and 35PSU but the exoskeleton of the juveniles at 22PSU contained significantly less calcium. Ocean acidification may affect aspects of E. marinus development but exposure to realistic low salinities appear, in the short term, to be more important in impacting development than exposure to CO2 acidified sea water at levels predicted for 300 years time.