Meeting Abstract

7.5  Friday, Jan. 4  Variation in size of juvenile corals and sensitivity to ocean acidification TARRANT, AM*; MCCORKLE, DC; DEPUTRON, SJ; CHURCH, C; HENRY, J; COHEN, AL; Woods Hole Oceanographic Institution; Woods Hole Oceanographic Institution; Bermuda Institute of Ocean Sciences; Woods Hole Oceanographic Institution; Woods Hole Oceanographic Institution; Woods Hole Oceanographic Institution atarrant@whoi.edu

Anthropogenic input of carbon dioxide into the atmosphere has resulted in a decline of pH in the surface ocean (ocean acidification), leading to decreases in the carbonate ion concentration and aragonite saturation state. In laboratory experiments, decreased aragonite saturation state can lead to decreases in skeletal growth of both adult and juvenile corals. In experiments conducted with corals and other animals, individuals vary in their apparent resistance or sensitivity to the effects of acidification. To investigate possible maternal effects on coral growth and sensitivity to ocean acidification, we collected brooded larvae released by nine maternal colonies of Porites astreoides, settled them on tiles and reared them for two weeks under conditions of ambient or elevated carbon dioxide (targeting aragonite saturation states of 3.6 and 1.6, respectively). The maternal colonies produced larvae that varied substantially in settlement success, ranging from 2-54%. After two weeks, polyp diameter and weight varied significantly among maternal colonies, but little to no difference was observed in response to CO2. These experiments demonstrate that over a short time period, P. astreoides juveniles appear to be relatively insensitive to moderate acidification. Under controlled conditions, maternal colonies produce offspring that vary dramatically in their settlement rates and size, which may lead to differential survival and eventual recruitment. Further experiments are needed to identify the environmental and/or genetic factors that contribute to these differences.