南沙珊瑚礁对大气CO_2含量上升的响应

Response of coral reef in Nansha waters to increasing atmospheric CO_2

本文利用南沙海域的碳酸盐化学以及相关调查资料,分析了表层CaCO3饱和度的分布特征,通过碳酸盐的热力学计算模式,定量评估了未来大气CO2增加对表层CaCO3饱和度的潜在影响,利用CaCO3饱和度与珊瑚钙化速率的经验关系式,进一步预测了珊瑚礁对大气CO2上升可能产生的生物地球化学响应.初步结果显示,工业革命前至2100年,南沙海域的CaCO3饱和度将下降43%左右,从而将引起珊瑚礁的平均钙化速率减少33%.如果未来大气CO2浓度继续保持目前的上升趋势,南沙海域珊瑚礁可能会停止生长,甚至某些造礁生物面临灭绝的危险.

Carbonate and related physical, chemical data obtained during April to May of 2001 in Nansha waters were utilized to describe the distribution characteristics of calcite and aragonite saturation degree. The potential effect of increased atmospheric CO2 on the degree of carbonate saturation in the surface waters were estimated by using the thermodynamic calculations, furthermore, the biogeochemical responses of coral reefs to rising atmospheric CO2 were predicted by using the empirical relationship between the relative rate of calcification and the degree of carbonate saturation. The preliminary results showed that the degree of carbonate saturation would have decreased to about 43 %, and the reduced saturation degree would lead to an average 33% decrease in calcification rate of coral reefs from pre-industrial to 2100. in future if increasing rate of atmospheric CO2 remains constant at present level, the coral reefs would likely stop growing, and some calcifying organisms might be in danger of extinction in the Nansha Waters.