Coastal areas around Antarctica such as the Amundsen Sea are important sources of trace metals and biological hotspots, but are also experiencing the effects of climate change, including the rapid thinning of ice sheets. In the central Amundsen Sea Polynya (ASP), both bio-essential dissolved Fe (DFe) and dissolved Mn (DMn) were found to be depleted at the surface, indicating substantial biological uptake and/or precipitation. Close to the Dotson Ice Shelf (DIS) there were elevated surface concentrations of DMn (>3 nM) but surprisingly not for DFe (<0.3 nM). While Fe-binding ligand data suggests that ligands were abundant near the DIS, these were most likely not strong enough to outcompete scavenging and thus increase DFe substantially in the outflow. In contrast to the dissolved phase, particulate Fe (PFe) and Mn (PMn) concentrations (both labile and refractory fractions) were elevated over the entire water column close to the DIS and partly in the central ASP. We hypothesize that DFe was released from the DIS and immediately established an equilibrium with the labile particulate Fe (L-PFe)pool, via (reversible) scavenging, as indicated by a positive correlation between L-PFe and DFe in the outflow. This scavenging results in relatively low DFe concentrations, but the pool of labile PFe likely buffers the DFe pool when DFe is decreasing, e.g. due to uptake by phytoplankton. The DFe distribution also shows that inflowing modified circumpolar deep water (mCDW) and benthic sediments are clear and important sources for both DFe and DMn in the ASP. Refractory Fe and Mn likely have a lithogenic source, whereas the labile fractions are mostly biogenic in surface waters, and authigenic in deep waters (>100 m depth). We compared different uptake ratios, underlining that uptake ratio estimates do not necessarily capture natural variability and it is likely better to use a range of values. In the future, climate change may increase the heat flux of mCDW and thereby the melting of the DIS. This will most likely cause an increased input of Fe and Mn into the ASP, which may fuel increased levels of primary productivity in the ASP.

南极洲周围的沿海地区，如阿蒙森海，是微量金属和生物热点的重要来源，但也受到气候变化的影响，包括冰盖迅速变薄。在阿蒙森海波利尼亚 (ASP) 中部，发现生物必需的溶解铁 (DFe) 和溶解的锰 (DMn) 在地表耗尽，表明大量生物吸收和/或沉淀。在 Dotson 冰架 (DIS) 附近，DMn (>3 nM) 的表面浓度升高，但令人惊讶的是 DFe (<0.3 nM) 没有。虽然 Fe 结合配体数据表明配体在 DIS 附近很丰富，但这些配体很可能不足以胜过清除，因此在流出物中显着增加了 DFe。与溶解相相比，颗粒 Fe (PFe) 和 Mn (PMn) 浓度（不稳定和耐火部分）在靠近 DIS 的整个水柱中和部分在中央 ASP 中升高。我们假设 DFe 从 DIS 中释放出来，并通过（可逆）清除立即与不稳定的颗粒 Fe (L-PFe) 池建立平衡，如流出物中 L-PFe 和 DFe 之间的正相关所示。浮游植物。DFe 分布还表明，流入的改性环极深水 (mCDW) 和底栖沉积物是 ASP 中 DFe 和 DMn 的明确和重要来源。难熔的 Fe 和 Mn 可能有成岩来源，而不稳定的部分主要在地表水中是生物成因的，而在深水（>100 m 深度）中是自生的。我们比较了不同的吸收率，强调吸收率估计不一定能捕捉到自然变异性，使用一系列值可能会更好。未来，气候变化可能会增加 mCDW 的热通量，从而导致 DIS 的融化。这很可能会导致 ASP 中的 Fe 和 Mn 输入增加，这可能会推动 ASP 中初级生产力水平的提高。