Effect of calcium carbonate saturation state on the calcification rate of an experimental coral reef

作者：Chris Langdon, Taro Takahashi, Colm Sweeney, Dave Chipman, John G. Goddard, Francesca Marubini, Heather L. Aceves, H. Barnett, Marlin J. Atkinson · 发表于：Global Biogeochemical Cycles · 年份：2000 · DOI：10.1029/1999gb001195 · 被引用次数：626 · 研究领域：Coral and Marine Ecosystems Studies、Ocean Acidification Effects and Responses、Marine and coastal ecosystems

The concentration of CO 2 in the atmosphere is projected to reach twice the preindustrial level by the middle of the 21st century. This increase will reduce the concentration of CO 3 2− of the surface ocean by 30% relative to the preindustrial level and will reduce the calcium carbonate saturation state of the surface ocean by an equal percentage. Using the large 2650 m 3 coral reef mesocosm at the BIOSPHERE‐2 facility near Tucson, Arizona, we investigated the effect of the projected changes in seawater carbonate chemistry on the calcification of coral reef organisms at the community scale. Our experimental design was to obtain a long (3.8 years) time series of the net calcification of the complete system and all relevant physical and chemical variables (temperature, salinity, light, nutrients, Ca 2+ , p CO 2 , T CO 2 , and total alkalinity). Periodic additions of NaHCO 3 , Na 2 CO 3 , and/or CaCl 2 were made to change the calcium carbonate saturation state of the water. We found that there were consistent and reproducible changes in the rate of calcification in response to our manipulations of the saturation state. We show that the net community calcification rate responds to manipulations in the concentrations of both Ca 2+ and CO 3 2− and that the rate is well described as a linear function of the ion concentration product, [Ca 2+ ] 0.69 [CO 3 2− ]. This suggests that saturation state or a closely related quantity is a primary environmental factor that influences calcifica...