Responses of harpacticoid copepods according to the various exposure methods as regards ocean acidification

Abstract

In recent years, many studies are carried out on the effect of increased dissolved carbon dioxide in seawater and reduced seawater pH (ocean acidification). For our studies, as part of growing need to ascertain the effects of ocean acidification on marine ecosystem and organisms, harpacticoid copepods, one of the most abundant meiofaunal groups were subjected to laboratory experiments. We evaluated and compared the responses of harpacticoid copepods using different exposure methods to determine the most efficient experimental method to various concentrations of dissolved CO2 in seawater. Survival rates of harpacticoid copepods collected from the tidal flat were 35% in control groups exposed to 400 ppm and 30% in treatment groups exposed to 1000 ppm for 48 hours. Survival rates from the experiments using the CO2-addition experimental system at the Seto Marine Biological Laboratory, Kyoto University, were 63.3% in control groups exposed to 400 ppm, 55% and 55.4% in treatment groups exposed to 600 and 1000 ppm for 24 hours. Specific survival rates of Tigriopus japonicus, one of harpacticoid species, were 93% in control groups, and 80% in treatment groups exposed to 1000 ppm for 48 hours.ation on marine ecosystem and organisms, harpacticoid copepods, one of the most abundant meiofaunal groups were subjected to laboratory experiments. We evaluated and compared the responses of harpacticoid copepods using different exposure methods to determine the most efficient experimental method to various concentrations of dissolved CO2 in seawater. Survival rates of harpacticoid copepods collected from the tidal flat were 35% in control groups exposed to 400 ppm and 30% in treatment groups exposed to 1000 ppm for 48 hours. Survival rates from the experiments using the CO2-addition experimental system at the Seto Marine Biological Laboratory, Kyoto University, were 63.3% in control groups exposed to 400 ppm, 55% and 55.4% in treatment groups exposed to 600 and 1000 ppm for 24 hours. Specific survival rates of Tigriopus japonicus, one of harpacticoid species, were 93% in control groups, and 80% in treatment groups exposed to 1000 ppm for 48 hours.