Sources and reaction pathways of soluble Fe from the Western Antarctic Peninsula to the Southern Ocean

本研究的目的是揭示南大洋中靠近海洋岛屿的区域可溶性铁的高供应来源和机制，这些区域通常具有刺激浮游生物生长的作用。本研究将以南极半岛西部的乔治王岛为研究对象。利用冰川冲刷物、陆架沉积物和孔隙水、水柱剖面样条的铁同位素，结合全成岩无机地球化学剖面，对铁的来源和供给路径进行指纹识别。鉴于全球变暖导致KGI冰川快速退缩和冰川侵蚀物质外流加剧，本文将研究三种可能的反应途径：1)高生产力推动铁的早期成岩再循环和沉积物扩散；2)表层沉积物中固体活性铁相（包括成岩铁氧化物）的聚集和再悬浮；3)冰川冲洗液直接溶解活性铁矿物和富铁硅酸盐。为了解决铁供应途径的动态及其与气候变化的潜在关系，将高外溢区（波特湾，麦克斯韦湾）与低外溢区（金钟湾）进行比较。

The objective of this study is to reveal sources and mechanisms responsible for high supply of soluble Fe in regions close to ocean islands in the otherwise HPLC Southern Ocean with the common effect of stimulating plankton growth. The focus of this study will be on King George Island (KGI), Western Antarctic Peninsula. Fe isotopes from glacial outwash material, shelf sediments and porewaters, and transects of water column profiles together with full diagenetic inorganic geochemical profiling will be used to fingerprint Fe sources and supply pathways. In the light of rapid glacier retreat on KGI due to global warming and enhanced outwash of glacially eroded material, three possible reaction pathways will be investigated: 1) early diagenetic recycling of Fe and diffusion out of sediments fuelled by high productivity; 2) accumulation and resuspension of solid reactive Fe phases (including diagenetic Fe-oxyhydroxides) in surface sediments; 3) direct dissolution of reactive Fe minerals and Fe-rich silicates from glacial outwash. In order to address the dynamics of Fe supply pathways and a potential relationship to climate change, high outwash regions (Potter Cove, Maxwell Bay) will be compared with a low outwash region (Admiralty Bay).