Seawater carbonate chemistry and processes during experiments with Emiliania huxleyi, 2008

Ocean acidification in response to rising atmospheric CO2 partial pressures is widely expected to reduce calcification by marine organisms. From the mid-Mesozoic, coccolithophores have been major calcium carbonate producers in the world's oceans, today accounting for about a third of the total marine CaCO3 production. Here, we present laboratory evidence that calcification and net primary production in the coccolithophore species Emiliania huxleyi are significantly increased by high CO2 partial pressures. Field evidence from the deep ocean is consistent with these laboratory conclusions, indicating that over the past 220 years there has been a 40% increase in average coccolith mass. Our findings show that coccolithophores are already responding and will probably continue to respond to rising atmospheric CO2 partial pressures, which has important implications for biogeochemical modeling of future oceans and climate.

大气二氧化碳分压升高所引发的海洋酸化，学界普遍认为会降低海洋生物的钙化作用。中生代中期以来，颗石藻（coccolithophore）便一直是全球海洋中主要的碳酸钙生产者，目前其贡献约占全球海洋总碳酸钙产出的三分之一。本研究提供实验室证据表明，高二氧化碳分压可显著提升赫氏颗石藻（Emiliania huxleyi）的钙化作用与净初级生产力。深海野外观测得到的证据与上述实验室结论一致，表明在过去220年间，颗石藻的平均颗石质量已提升40%。本研究结果显示，颗石藻现已对大气二氧化碳分压升高产生响应，且未来大概率仍将持续响应，这一发现对未来海洋与气候的生物地球化学建模具有重要意义。