To understand the effects of lower pH levels due to elevated CO2 and salinity, we designed and constructed a pH-control system that included automatic CO2 infusion and measured the hatching rate of a crustacean model species, Artemia franciscana. The pH-control system was cost-effective and capable of performing animal tests in which pH fluctuated around 8.0 ± 0.1, with the temperature around 27 ± 0.5°C. Hatching rate was observed under four different pH levels (7.0, 7.3, 7.6, and untreated control) combined with three salinity ranges (15, 25, and 35 ppt). The results demonstrated that lower pH levels led to decreased hatching rates regardless of salinity, and the minimum hatching rate was detected at pH 7.0 compared to the control (pH 8.0 ± 0.1), supporting the idea that OA has adverse effects on hatching rates and increases the risk of juveniles being introduced in the ecosystem. In contrast, salinity changes exhibited no synergistic effects with pH and had independent effects.
Salma U., Uddowla H. Md., Lee G., Yeo Y. & Kim H.-W., 2012. Effects of pH change by CO2 induction and salinity on the hatching rate of Artemia franciscana. Fisheries and Aquatic Sciences 15(2): 177-181. Article.