Effect of acidified seawater and high temperature on the survival and behaviour of supralittoral and sublittoral amphipods (Crustacea)

Abstract

Amphipods are one of the most diverse groups of marine crustaceans. The impacts of changing environmental parameters on such organisms are unclear. The study aimed to determine the effect of low pH and high temperatures on the survival and behaviour of two amphipods from contrasting environments; namely Platorchestia cf platensis (supralittoral) and Cymadusa filosa (sublittoral). Amphipods were collected from the field, exposed to artificially acidified seawater (pH 7.0, 6.0, 5.0), and to temperatures of 30 - 39ºC. C. filosa could not build tubes, and P. platensis did not display its normal jumping behaviour but remained burrowed in the sediment at low pH and high temperatures. P. platensis was tolerant to 33ºC but not to 36ºC and 39ºC. High temperatures (30ºC, 33ºC, 36ºC) are lethal to C. filosa (100% mortality recorded within 10 days). P. platensis was able to tolerate pH variations with at least 50% survival at the end of 4 weeks. C. filosa do not survive more than 20 days at the lowest pH treatment (7.0). There was no significant difference between survival rates of the males, females and juveniles of both species (p>0.05) at the various temperatures and pH. Size and gender had little effect on the tolerance of the individual amphipod species. P. platensis was found to be more tolerant to changes compared to C. filosa. The current study provides insights into the species-specific nature of responses, survival and behaviour of organisms due to climate change related environmental parameters.