coral larvae under ocean acidification survival, metabolism, and metamorphosis珊瑚幼虫在海洋酸化生存、新陈代谢和蜕变.pdfVIP

Coral Larvae under Ocean Acidification: Survival, Metabolism, and Metamorphosis 1 ¤ 1 2 1 Masako Nakamura * , Shun Ohki , Atsushi Suzuki , Kazuhiko Sakai 1 Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan, 2 Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan Abstract Ocean acidification may negatively impact the early life stages of some marine invertebrates including corals. Although reduced growth of juvenile corals in acidified seawater has been reported, coral larvae have been reported to demonstrate some level of tolerance to reduced pH. We hypothesize that the observed tolerance of coral larvae to low pH may be partly explained by reduced metabolic rates in acidified seawater because both calcifying and non-calcifying marine invertebrates could show metabolic depression under reduced pH in order to enhance their survival. In this study, after 3-d and 7-d exposure to three different pH levels (8.0, 7.6, and 7.3), we found that the oxygen consumption of Acropora digitifera larvae tended to be suppressed with reduced pH, although a statistically significant difference was not observed between pH conditions. Larval metamorphosis was also observed, confirming that successful recruitment is impaired when metamorphosis is disrupted, despite larval survival. Results also showed that the metamorphosis rate significantly decreased under acidified seawater conditions after both short (2 h) and long (7 d) term exposure. These results imply that acidified seawater impacts larval physiology, suggesting that suppressed metabolism and metamorphos