Biogeochemical control of the coupled CO2-O 2 system of the Baltic Sea: a review of the results of Baltic-C.

Past, present, and possible future changes in the Baltic Sea acid–base and oxygen balances were studied using different numerical experiments and a catchment–sea model system in several scenarios including business as usual, medium scenario, and the Baltic Sea Action Plan. New CO2 partial pressure data provided guidance for improving the marine biogeochemical model. Continuous CO2 and nutrient measurements with high temporal resolution helped disentangle the biogeochemical processes. These data and modeling indicate that traditional understandings of the nutrient availability–organic matter production relationship do not necessarily apply to the Baltic Sea. Modeling indicates that increased nutrient loads will not inhibit future Baltic Sea acidification; instead, increased mineralization and biological production will amplify the seasonal surface pH cycle. The direction and magnitude of future pH changes are mainly controlled by atmospheric CO2 concentration. Apart from decreasing pH, we project a decreasing calcium carbonate saturation state and increasing hypoxic area.

通过不同的数值实验以及一个集水区 - 海洋模型系统，在包括“一切照旧”、“中度情景”和《波罗的海行动计划》在内的几种情景下，对波罗的海酸碱和氧平衡过去、现在以及可能的未来变化进行了研究。新的二氧化碳分压数据为改进海洋生物地球化学模型提供了指导。具有高时间分辨率的连续二氧化碳和营养物质测量有助于理清生物地球化学过程。这些数据和模型表明，对营养物质可利用性 - 有机物生产关系的传统理解不一定适用于波罗的海。模型显示，营养物质负荷增加不会抑制未来波罗的海的酸化；相反，矿化作用和生物生产的增加将放大季节性表层pH值循环。未来pH值变化的方向和幅度主要受大气二氧化碳浓度控制。除了pH值下降，我们还预测碳酸钙饱和度会降低，缺氧区域会增加。