Hendry Katharine R, Sales de Freitas Felipe, Arndt Sandra, Beaton Alexander, Friberg Lisa, Hatton Jade E, Hawkings Jonathan R, Jones Rhiannon L, Krause Jeffrey W, Meire Lorenz, Ng Hong Chin, Pryer Helena, Tingey Sarah, van de Velde Sebastiaan J, Wadham Jemma, Wang Tong, Woodward E Malcolm S
British Antarctic Survey, High Cross, Cambridge, UK.
School of Earth Sciences, University of Bristol, Bristol, UK.
Commun Earth Environ. 2025;6(1):305. doi: 10.1038/s43247-025-02264-7. Epub 2025 Apr 19.
The polar regions are biologically productive and play a critical role in regional and global biogeochemical cycling. A key nutrient is dissolved silicon, required for the growth of siliceous phytoplankton, diatoms, which form an important component of polar ecosystems. Glacial weathering is thought to be an important dissolved silicon source to coastal waters, especially critical in regions experiencing seasonal silicon limitation of diatom growth. However, complex physical and biogeochemical interactions in fjords and coastal regions modulate the downstream supply of dissolved and particulate nutrients, including silicon. Here, we review the biogeochemical complexities of glaciated margins and the insights into this system that silicon isotope geochemistry offer. We show that stable and radioisotopic measurements and biogeochemical numerical modelling provide a quantitative mechanistic understanding of subglacial silica mobilisation and its cycling across the land-ocean continuum. Subglacial weathering produces isotopically light amorphous silica, which dissolves in seawater to release dissolved silicon. Our findings show that isotopically light, detrital silica, likely containing glacial material, reaches the ocean and there could support a substantial proportion of diatom productivity, especially in the Arctic. Outstanding questions about silicon cycling in these crucial environments will be addressed through novel and cross-discipline approaches that overcome traditionally viewed ecosystem boundaries.
极地地区生物生产力高，在区域和全球生物地球化学循环中发挥着关键作用。一种关键营养素是溶解态硅，它是硅质浮游植物（硅藻）生长所必需的，而硅藻是极地生态系统的重要组成部分。冰川风化被认为是沿海水域溶解态硅的重要来源，在经历硅藻生长季节性硅限制的地区尤为关键。然而，峡湾和沿海地区复杂的物理和生物地球化学相互作用调节了包括硅在内的溶解态和颗粒态营养素的下游供应。在这里，我们综述了冰川边缘的生物地球化学复杂性以及硅同位素地球化学对该系统的见解。我们表明，稳定同位素和放射性同位素测量以及生物地球化学数值模拟为冰川下二氧化硅的 mobilisation 及其在陆地 - 海洋连续体中的循环提供了定量的机理理解。冰川下风化产生同位素轻的无定形二氧化硅，它溶解在海水中释放出溶解态硅。我们的研究结果表明，同位素轻的碎屑硅，可能含有冰川物质，进入海洋，并且可能支持相当一部分硅藻的生产力，特别是在北极地区。通过克服传统上看待的生态系统边界的新颖和跨学科方法，将解决这些关键环境中关于硅循环的突出问题。
