Detection and projection of carbonate dissolution in the water column and deep‐sea sediments due to ocean acidification
Detection and projection of carbonate dissolution in the water column and deep‐sea sediments due to ocean acidification
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DOI：
10.1029/2012gl051272
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发表时间：
2012-03
影响因子：
5.2
通讯作者：
T. Ilyina;R. Zeebe
中科院分区：
文献类型：
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作者：
T. Ilyina;R. Zeebe
化石燃料CO2在海水中的溶解导致碳酸盐离子浓度降低和海水pH值降低，可能对许多海洋生物产生负面影响。我们项目可检测的变化碳酸盐溶解和评估其潜力，以减轻大气CO2和海洋酸化与全球海洋地球化学模型HAMOCC被迫不同的CO2排放情景。我们的研究结果表明，随着人为CO2信号渗透到海洋内部，碳酸盐矿物的饱和状态将急剧下降-在下一个世纪，从海底到100-150 m深度的欠饱和延伸。这将导致大量的碳酸钙溶解在水柱和沉积物中，在未来2500年内，海洋表面和海洋内部的总碱度（TA）将增加180 μmol kg−1。模型结果表明，不同海洋盆地之间的反应不均匀：大西洋碳酸盐化学反应更快，在二氧化碳排放停止后两千年开始恢复，而太平洋的情况并非如此。CaCO 3雨在2230年左右在太平洋停止。使用观测得出的TA检测阈值，我们预测仅在2070年在表层海洋中以及2230年和2500年后在大西洋和太平洋深处分别出现可检测的溶解驱动变化。我们发现，不同的模型假设溶解和钙化率对未来的预测影响不大。相反，人为CO2排放量压倒性地控制着海洋化学的扰动程度。总之，海洋碳酸盐溶解在下一个千年减缓大气CO2和海洋酸化方面的潜力微不足道。
Dissolution of fossil fuel CO2 in seawater results in decreasing carbonate ion concentration and lowering of seawater pH with likely negative impacts for many marine organisms. We project detectable changes in carbonate dissolution and evaluate their potential to mitigate atmospheric CO2 and ocean acidification with a global biogeochemistry model HAMOCC forced by different CO2 emission scenarios. Our results suggest that as the anthropogenic CO2 signal penetrates into ocean interior, the saturation state of carbonate minerals will drop drastically – with undersaturation extending from the ocean floor up to 100–150 m depth in the next century. This will induce massive dissolution of CaCO3 in the water column as well as the sediment, increasing the Total Alkalinity (TA) by up to 180 μmol kg−1 at the surface and in the ocean interior over the next 2500 years. Model results indicate an inhomogeneous response among different ocean basins: Atlantic carbonate chemistry responds faster and starts recovering two millennia after CO2 emissions cease, which is not the case in the Pacific. CaCO3rain stops in the Pacific Ocean around 2230. Using an observation‐derived detection threshold for TA, we project detectable dissolution‐driven changes only by the year 2070 in the surface ocean and after 2230 and 2500 in the deep Atlantic and Pacific respectively. We show that different model assumptions regarding dissolution and calcification rates have little impact on future projections. Instead, anthropogenic CO2 emissions overwhelmingly control the degree of perturbation in ocean chemistry. In conclusion, ocean carbonate dissolution has insignificant potential in mitigating atmospheric CO2 and ocean acidification in the next millennia.