期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2014
卷号：111
期号：46
页码：16303-16308
DOI：10.1073/pnas.1414323111
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThis approach of estimating basin-scale calcification rates and the relative role of margins (reefs) versus pelagic carbonate deposition can be applied as a long-term monitoring scheme for the effects of ocean acidification. The database for the response of individual organisms to elevated CO2 levels is growing steadily, but in situ measurements assessing this response are very local. The study demonstrates the feasibility of estimating the relative calcification rates of planktonic and benthic populations over a whole basin and provides a tool for the monitoring of these complex systems on large spatial scales. Basin-scale calcification rates are highly important in assessments of the global oceanic carbon cycle. Traditionally, such estimates were based on rates of sedimentation measured with sediment traps or in deep sea cores. Here we estimated CaCO3 precipitation rates in the surface water of the Red Sea from total alkalinity depletion along their axial flow using the water flux in the straits of Bab el Mandeb. The relative contribution of coral reefs and open sea plankton were calculated by fitting a Rayleigh distillation model to the increase in the strontium to calcium ratio. We estimate the net amount of CaCO3 precipitated in the Red Sea to be 7.3 {+/-} 0.4{middle dot}1010 kg{middle dot}y-1 of which 80 {+/-} 5% is by pelagic calcareous plankton and 20 {+/-} 5% is by the flourishing coastal coral reefs. This estimate for pelagic calcification rate is up to 40% higher than published sedimentary CaCO3 accumulation rates for the region. The calcification rate of the Gulf of Aden was estimated by the Rayleigh model to be [~]1/2 of the Red Sea, and in the northwestern Indian Ocean, it was smaller than our detection limit. The results of this study suggest that variations of major ions on a basin scale may potentially help in assessing long-term effects of ocean acidification on carbonate deposition by marine organisms.
