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OLI Grant: Investigating Environmental Controls on Coral Calcification

Grant Funded: 2005

Changes in surface ocean temperature and chemistry caused by increasing atmospheric CO2 pose two of the major threats to global coral reef health this century - temperature through its impact on coral-algal symbiosis and seawater carbonate chemistry through its influence on aragonite precipitation rates. Model predictions of the impacts of these changes on reef building are limited by lack of quantitative data regarding the relative contributions of light, temperature, nutrients, tide, and [CO32-] to coral calcification. The proposed work seeks to quantify the contributions of key environmental parameters to calcification rates of hermatypic and ahermatypic species in a natural environment on time scales of weeks to years. Despite relatively low species diversity and coral cover, the marine environment surrounding the Liquid Jungle Laboratory (LJL) on the Isla Canales de Tierra, Panama, presents a uniquely interesting site for this study. Unlike most tropical & subtropical reefs, LJL corals experience large, abrupt changes in temperature, seawater salinity, nutrient flux (via upwelling and runoff) and - we’re predicting - carbonate chemistry and light through the year, against a background of relatively constant seasonal insolation. Also unlike most reefs today, this site is removed from the direct anthropogenic activities such as overfishing, dynamiting and pollution that would impact calcification rates and confound our efforts to resolve the various environmental forcings. Our main activities will be (1) deployment of in- situ logging devices to measure temperature and photosynthetically active radiation (PAR) on two discrete coral sites, weekly sampling of seawater for salinity, carbonate chemistry, and nutrient and trace element concentrations, and, (2) periodic in situ staining of select coral colonies and microCT analysis of core samples from these colonies to quantify daily-weekly calcification rates over the study period. These environmental data and calcification rate estimates will provide an essential first step toward a long-term study of coral calcification at the LJL, in which we will investigate and anticipate the impact of anthropogenic CO2 release on coral calcification and reef health.

Originally published: February 1, 2005