(Table 1) Vertical turbulent eddy diffusivity of selected stations from the Nathaniel B. Palmer cruise NBP09-01

Dissolved iron (DFe) and total dissolvable Fe (TDFe) were measured in January-February 2009 in Pine Island Bay, as well as in the Pine Island and Amundsen polynyas (Amundsen Sea, Southern Ocean). Iron (Fe) has been shown to be a limiting nutrient for phytoplankton growth, even in the productive continental shelves surrounding the Antarctic continent. However, the polynyas of the Amundsen Sea harbor the highest concentrations of phytoplankton anywhere in Antarctica. Here we present data showing the likely sources of Fe that enable such a productive and long lasting phytoplankton bloom. Circumpolar Deep Water (CDW) flows over the bottom of the shelf into the Pine Island Bay where DFe and TDFe were observed to increase from 0.2 to 0.4 nM DFe and from 0.3-4.0 to 7-14 nM TDFe, respectively. At the southern end of Pine Island Bay, the CDW upwelled under the Pine Island Glacier, bringing nutrients (including Fe) to the surface and melting the base of the glacier. Concentrations of DFe in waters near the Pine Island Glacier and the more westward lying Crosson, Dotson, and Getz Ice Shelves varied between 0.40 and 1.31 nM, depending on the relative magnitude of upwelling, turbulent mixing, and melting. These values represent maximum concentrations since associated ligands (which increase the solubility of Fe in seawater) were saturated with Fe (Thuroczy et al., 2012, doi:10.1016/j.dsr2.2012.03.009). The TDFe concentrations were very high compared to what previously has been measured in the Southern Ocean, varying between 3 and 106 nM. In the Pine Island Polynya, macronutrients and DFe were consumed by the phytoplankton bloom and concentrations were very low. We calculate that atmospheric dust contributed < 1% of the Fe necessary to sustain the phytoplankton bloom, while vertical turbulent eddy diffusion from the sediment, sea ice melt, and upwelling contributed 1.0-3.8%, 0.7-2.9%, and 0.4-1.7%, respectively. The largest source was Fe input from the PIG, which could satisfy the total Fe demand by the phytoplankton bloom by lateral advection of Fe over a range of 150 km from the glacier. The role of TDFe as a phytoplankton nutrient remains unclear, perhaps representing an important indirect Fe source via dissolution and complexation by dissolved organic ligands (Gerringa et al., 2000, doi:10.1016/S0304-4203(99)00092-4; Borer et al., 2005, doi:10.1016/j.marchem.2004.08.006).2009年1—2月，研究人员于派恩岛湾（Pine Island Bay）以及南大洋阿蒙森海（Amundsen Sea）区域的派恩岛冰间湖与阿蒙森冰间湖（Pine Island and Amundsen polynyas）中，对溶解态铁（Dissolved iron, DFe）与总可溶态铁（Total dissolvable Fe, TDFe）开展了测定。铁（Fe）被证实为浮游植物生长的限制性营养盐，即便在南极大陆周边生产力旺盛的大陆架海域亦是如此。然而，阿蒙森海的冰间湖孕育着南极全域浮游植物生物量最高的海域。本研究呈现的数据，揭示了支撑该区域高产且持久的浮游植物水华所需铁元素的潜在来源。 绕极深层水（Circumpolar Deep Water, CDW）沿陆架底部流入派恩岛湾，观测显示该海域内DFe浓度由0.2 nM升至0.4 nM，TDFe浓度则由0.3~4.0 nM升至7~14 nM。在派恩岛湾南端，绕极深层水在派恩岛冰川（Pine Island Glacier, PIG）下方发生涌升，将包括铁在内的营养盐带至表层，并消融冰川底部。派恩岛冰川附近，以及更西侧的克罗松冰架、多森冰架与格茨冰架周边海域的DFe浓度介于0.40~1.31 nM之间，其浓度变化取决于涌升流、湍流混合与冰川消融的相对强度。由于与铁结合、可提升海水中铁溶解度的相关配体已被铁饱和（Thuroczy等，2012，doi:10.1016/j.dsr2.2012.03.009），上述浓度代表了该区域的最高观测值。 本次测得的TDFe浓度远高于此前南大洋的实测结果，介于3~106 nM之间。在派恩岛冰间湖中，浮游植物水华消耗了大量营养盐与DFe，致使其浓度极低。经计算，维持浮游植物水华所需的总铁中，大气尘埃贡献占比不足1%；而来自沉积物、海冰融化与上升流的垂直湍流涡旋扩散分别贡献了1.0%~3.8%、0.7%~2.9%与0.4%~1.7%。最主要的铁来源为派恩岛冰川输入的铁，通过从冰川向外150 km范围的铁侧向平流输送，即可满足浮游植物水华的总铁需求。 总可溶态铁作为浮游植物营养盐的角色仍未明确，其或许可通过溶解有机配体的溶解与络合作用，成为重要的间接铁来源（Gerringa等，2000，doi:10.1016/S0304-4203(99)00092-4；Borer等，2005，doi:10.1016/j.marchem.2004.08.006）。