Carbon dioxide (CO2) enrichment in seawater because of increased use of fossil fuels can possibly cause detrimental effects on the physiological processes of marine life, especially shell builders, due to CO2-induced ocean acidification. We investigated, for the first time, specifically the effect of CO2 enrichment on post-ecydsial shell mineralization in Crustacea using the blue crab, Callinectes sapidus, as the model crustacean. It was hypothesized that CO2 enrichment of seawater would adversely affect exoskeletal mineralization in the blue crab. This experiment used two groups of post-ecydsial crabs, with one group exposed to seawater at a pH of 8.20 and the other group treated with CO2-acidified seawater with a pH of 7.80 – 7.90. After a period of 7 days, samples of exoskeleton and hemolymph were collected from the survivors. CO2 enrichment was found to significantly increase exoskeletal magnesium content by 104% relative to control, while a statistically non-significant elevation of 31% in exoskeletal calcium was registered. Because CO2 treatment did not change the content of magnesium and calcium in the hemolymph, we postulate herein that increased exoskeletal mineralization in post-ecydsial blue crabs must stem from an increased influx of bicarbonate ions from the medium through the gill, to the hemolymph, and across the epidermis. Additionally, the observed significant increase in the mass of exoskeleton following CO2 treatment must be at least partly accounted for by enhanced postmolt carbonate salt deposition to the shell.
Soorya Y. & Zou E., in press. How does CO2-induced acidification affect post-ecydsial exoskeletal mineralization in the blue crab, Callinectes sapidus?. Environmental Toxicology and Chemistry. Article.
