Meeting Abstract

4.2  Monday, Jan. 4  Effects of elevated atmospheric CO₂ on growth in newly-settled coral polyps ROGERS-LOWERY, CL; Catawba College clowery@catawba.edu

As levels of atmospheric carbon dioxide increase due to anthropogenic causes, it is projected that the pH of the oceans will become more acidic. Lower pH decreases aragonite saturation of seawater and may, as a consequence, negatively impact the growth and survival of coral While much research has been dedicated to the impact of CO₂ levels on calcification and other physiological mechanisms of adult coral, little has dealt with early developmental stages. In the current study, newly-settled polyps of the coral Favia fragum were exposed to different levels of atmospheric CO₂ and growth was measured over 12 weeks. The average growth of coral in normal conditions (380 ppm CO₂) was 987.5±135.3% of initial polyp area, which was significantly greater than those reared under conditions of 600 and 1000 ppm CO₂ (408.8±81.3% and 248.9±44.6%, respectively). Other parameters of growth and physiological state, including protein content to skeletal weight ratio, calcium content, and ultrastructure of the skeleton, were compared between coral reared in normal and elevated atmospheric CO₂. The oceans deposit a very important amount of carbon through calcification in marine organisms. If calcification of cnidarians is lowered significantly, then it is possible that on a global scale much less carbon will be sequestered by the oceans. This could then lead decreased ability of the oceans to absorb the surplus carbon from the atmosphere, leading to accelerated climate change.