Cellular responses of encapsulated gastropod embryos to multiple stressors associated with climate change

As a consequence of global warming, environmental conditions such as temperature and salinity are likely to change in near-shore waters. Early life history phases are expected to be particularly vulnerable to changes in these abiotic variables. To evaluate the effect of multiple stressors on the responses of invertebrate larvae, to conditions anticipated under scenarios of climate change, we examined the cellular responses of embryos of three common rocky intertidal gastropod species to temperature and salinity changes. Encapsulated embryos of each species were exposed for 72 h to six combinations of ecologically realistic temperature and salinity levels (22° and 30 °C and 25, 35 and 45 ppt). Embryonic mortality and the responses of two biomarkers: total antioxidant capacity and lipid peroxidation, were then determined. We predicted that those organisms exposed to physiologically stressful levels of the combined stressors would show the strongest responses. The general trend was that both extremes of salinity (25 and 45 ppt) and high temperature (30 °C) negatively affected the embryos studied inducing oxidative stress and increasing lipid peroxidation, leading to increased embryonic mortality. The intensity of the response remained species-specific, with no clear pattern established as to which species was the most sensitive to salinity and temperature changes. Consequently, climate change induced temperature and salinity changes do exert molecular and physiological effects on early life stages of rocky shore gastropods, however, response to these stressors is species-specific.