What Controls the Variability of the Southern Ocean Productivity and Carbon Uptake?

由于我们对海洋生态系统对物理强迫、海洋迁移和气候变化的反应的了解不全面，南大洋生物生产力的可变性以及相应的碳吸收，包括化石燃料二氧化碳的吸收，受到了阻碍。这项建模研究将解决三个主要问题：i）气候动态和生物生产之间的联系机制是什么？ii）微量营养素铁限制的机制是什么以及不同铁源的相对重要性？中尺度涡旋对区域碳和铁收支的作用是什么？根据麻省理工学院的海洋环流模式（MITgcm），从南大洋状态估计中得出的允许涡流（1/60 x 1/60纬度; 42个深度）的物理环流场将受到一个非常大的南大洋特性观测数据集的约束。将对照观测到的表面叶绿素和海洋地球化学示踪剂的变化，对模型模拟进行测试，改进了对大陆架铁源的表示，并包括大气中分压增加与富含CO2的冷沃茨上涌之间的相互作用。这项研究应该会对最近和未来几年的碳和铁预算产生更真实的估计。该项目的教育方面将在格鲁吉亚理工学院培训一名研究生和一名本科生实习生进行地球系统建模。

The variability of the biological productivity and correspondingly the carbon uptake, including fossil fuel CO2, of the Southern Ocean are hampered by our incomplete understanding of the responses of the marine ecosystems to physical forcings, oceanic transport and climate change. This modeling study will address three main questions: i) what are the mechanism that link climate dynamics and biological production? ii) what are the mechanisms for micronutrient iron limitation and the relative importance of different iron sources? and iii) what are the roles of mesoscale eddies on regional carbon and iron budgets? Based on the MIT ocean general circulation model (MITgcm), eddy permitting (1/60 x 1/60 lat lon; 42 depth levels) physical circulation fields from the Southern Ocean State Estimate will be constrained by a very large observational data set of Southern ocean properties. Model simulations, with improved representations of iron sources from continental shelves, and including the interplay between increasing partial pressure (pCO2) in the atmosphere and upwelling of cold CO2 rich waters, will be tested against the observed variability of surface chlorophyll and biogeochemical tracers. This research should yield a more authentic estimate of the carbon, and iron budgets for recent and future years. Educational aspect of the project will train a graduate student and undergraduate student interns in earth-system modeling at Georgia Institute of Technology.