Changes in survival rates of the harpacticoid copepod, Tigriopus japonicus sensu lato, with increases in dissolved CO2 in seawater

Abstract

The recent rapid ocean acidification is expected to bring significant changes to the marine life. Accordingly, we used the entity of each growth stage of Harpacticoid copepod, believed to be ecologically important for its reaction, to the concentration of dissolved carbon dioxide (CO2). Tigriopus japonicus sensu lato was selected as the experimental organism and was categorized into either collected or adopted species. The concentrations of dissolved CO2 were 400, 1,000, and 1,550 ppm, and the changes in the survival rate over a 14-day period of the 2 different stages, adult and nauplius, were analyzed. The decrease in the survival rate escalated with the increase in the concentration over time. Particularly for the 1,550 ppm concentration, the survival rate decreased by more than 20% compared to 400 ppm at the end of the experiment. Furthermore, the survival rate decreased by a greater amount in all concentrations in nauplius rather than in the adult, and in the collected rather than in adopted species.oncentration of dissolved carbon dioxide (CO2). Tigriopus japonicus sensu lato was selected as the experimental organism and was categorized into either collected or adopted species. The concentrations of dissolved CO2 were 400, 1,000, and 1,550 ppm, and the changes in the survival rate over a 14-day period of the 2 different stages, adult and nauplius, were analyzed. The decrease in the survival rate escalated with the increase in the concentration over time. Particularly for the 1,550 ppm concentration, the survival rate decreased by more than 20% compared to 400 ppm at the end of the experiment. Furthermore, the survival rate decreased by a greater amount in all concentrations in nauplius rather than in the adult, and in the collected rather than in adopted species.