On the drivers of phytoplankton blooms in the Antarctic marginal ice zone: A modeling approach
On the drivers of phytoplankton blooms in the Antarctic marginal ice zone: A modeling approach
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DOI：
10.1029/2012jc008418
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发表时间：
2013
影响因子：
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通讯作者：
Marc H. Taylor;M. Losch;A. Bracher
中科院分区：
文献类型：
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作者：
Marc H. Taylor;M. Losch;A. Bracher
[1]南大洋的远洋区由于高纬度生长季节短、混合层深和铁的限制，初级生产水平一般较低。这包括春季和夏季海冰退缩期间边缘冰区（MIZ）的浮游植物水华。关于水华驱动因素的普遍假设是，海冰退缩通过产生融水增加了水柱的垂直稳定性，并在部分海冰覆盖的地区提供了免受风混合的庇护。这些条件有利于浮游植物的生长，使它们能够保持在水柱上游的位置。这项工作调查的驱动程序MIZ水华使用生化耦合的全球环流模式。结果支持这一假设，即与浅的、垂直稳定的水柱有关的物理条件（例如，混合层深度和可利用的光）是水华动态的最重要的预测因子，而营养限制的重要性较小。我们估计，MIZ水华占南大洋每年净初级生产量的15%，MIZ水华的早期阶段，发生在部分冰层覆盖和遥感不可见的情况下，约占该生产量的三分之二。与MIZ以外的类似生态省份相比，MIZ水华没有发现深度综合净初级生产力的提高，尽管假设表层沃茨浮游植物浓度升高为磷虾等食草生物提供了重要的摄食生境。
[1] The pelagic province of the Southern Ocean generally has low levels of primary production attributable to a short growing season in the higher latitudes, a deep mixed layer, and iron limitation. Exceptions include phytoplankton blooms in the marginal ice zone (MIZ) during spring and summer sea-ice retreat. The prevailing hypothesis as to the drivers of the blooms is that sea-ice retreat increases the vertical stability of the water column through the production of melt water and provides shelter from wind mixing in areas of partial sea-ice coverage. These conditions are favorable to phytoplankton growth by allowing them to maintain their position in the upper reaches of the water column. This work investigates the drivers of MIZ blooms using a biochemically coupled global circulation model. Results support the hypothesis in that physical conditions related to a shallow, vertically stable water column (e.g., mixed layer depth and available light) were the most significant predictors of bloom dynamics, while nutrient limitation was of lesser importance. We estimate that MIZ blooms account for 15% of yearly net primary production in the Southern Ocean and that the earlier phases of the MIZ bloom, occurring under partial ice coverage and invisible to remote sensing, account for about two thirds of this production. MIZ blooms were not found to enhance depth-integrated net primary production when compared to similar ecological provinces outside of the MIZ, although the elevated phytoplankton concentrations in surface waters are hypothesized to provide important feeding habitats for grazing organisms such as krill.