Center for Geomicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark.
GEOMAR, Helmholtz Centre for Ocean Research Kiel, Kiel, Germany.
Nat Commun. 2021 Mar 1;12(1):1349. doi: 10.1038/s41467-021-21558-w.
The Arctic has the highest warming rates on Earth. Glaciated fjord ecosystems, which are hotspots of carbon cycling and burial, are extremely sensitive to this warming. Glaciers are important for the transport of iron from land to sea and supply this essential nutrient to phytoplankton in high-latitude marine ecosystems. However, up to 95% of the glacially-sourced iron settles to sediments close to the glacial source. Our data show that while 0.6-12% of the total glacially-sourced iron is potentially bioavailable, biogeochemical cycling in Arctic fjord sediments converts the glacially-derived iron into more labile phases, generating up to a 9-fold increase in the amount of potentially bioavailable iron. Arctic fjord sediments are thus an important source of potentially bioavailable iron. However, our data suggests that as glaciers retreat onto land the flux of iron to the sediment-water interface may be reduced. Glacial retreat therefore likely impacts iron cycling in coastal marine ecosystems.
北极地区的升温速度是地球上最快的。冰川峡湾生态系统是碳循环和埋藏的热点，对这种变暖极为敏感。冰川对于从陆地向海洋输送铁非常重要，并为高纬度海洋生态系统中的浮游植物提供这种必需的营养物质。然而，高达 95%的冰川铁沉降到靠近冰川源的沉积物中。我们的数据表明，虽然 0.6-12%的总冰川铁具有潜在的生物可利用性，但北极峡湾沉积物中的生物地球化学循环将冰川衍生的铁转化为更活跃的相，从而使潜在生物可利用铁的数量增加了 9 倍。因此，北极峡湾沉积物是潜在生物可利用铁的重要来源。然而，我们的数据表明，随着冰川退回到陆地上，铁向沉积物-水界面的通量可能会减少。因此，冰川退缩可能会影响沿海海洋生态系统中的铁循环。
