Responses of the metabolism of the larvae of Pocillopora damicornis to ocean acidification and warming

PLoS One. 2014 Apr 25;9(4):e96172. doi: 10.1371/journal.pone.0096172. eCollection 2014.

Abstract

Ocean acidification and warming are expected to threaten the persistence of tropical coral reef ecosystems. As coral reefs face multiple stressors, the distribution and abundance of corals will depend on the successful dispersal and settlement of coral larvae under changing environmental conditions. To explore this scenario, we used metabolic rate, at holobiont and molecular levels, as an index for assessing the physiological plasticity of Pocillopora damicornis larvae from this site to conditions of ocean acidity and warming. Larvae were incubated for 6 hours in seawater containing combinations of CO2 concentration (450 and 950 µatm) and temperature (28 and 30°C). Rates of larval oxygen consumption were higher at elevated temperatures. In contrast, high CO2 levels elicited depressed metabolic rates, especially for larvae released later in the spawning period. Rates of citrate synthase, a rate-limiting enzyme in aerobic metabolism, suggested a biochemical limit for increasing oxidative capacity in coral larvae in a warming, acidifying ocean. Biological responses were also compared between larvae released from adult colonies on the same day (cohorts). The metabolic physiology of Pocillopora damicornis larvae varied significantly by day of release. Additionally, we used environmental data collected on a reef in Moorea, French Polynesia to provide information about what adult corals and larvae may currently experience in the field. An autonomous pH sensor provided a continuous time series of pH on the natal fringing reef. In February/March, 2011, pH values averaged 8.075 ± 0.023. Our results suggest that without adaptation or acclimatization, only a portion of naïve Pocillopora damicornis larvae may have suitable metabolic phenotypes for maintaining function and fitness in an end-of-the century ocean.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Anthozoa / metabolism*
  • Carbon Dioxide / chemistry
  • Citrate (si)-Synthase / metabolism
  • Global Warming
  • Hydrogen-Ion Concentration
  • Larva / metabolism
  • Oxygen Consumption
  • Pacific Ocean
  • Temperature

Substances

  • Carbon Dioxide
  • Citrate (si)-Synthase

Grants and funding

Funding was provided by the Moorea Coral Reef Long Term Ecological Research mini-grant awarded to E.B.R. and G.E.H. E.B.R. was supported by the National Science Foundation Graduate Research Fellowship Program. Portions of this project were supported by funds from the University of California in support of a multi-campus research program, Ocean Acidification: A Training and Research Consortium (http://oceanacidification.msi.ucsb.edu/) to G.E.H. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.