The Influence of Glacial Cover on Riverine Silicon and Iron Exports in Chilean Patagonia.
The Influence of Glacial Cover on Riverine Silicon and Iron Exports in Chilean Patagonia.
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DOI：
10.1029/2020gb006611
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发表时间：
2020-12
影响因子：
5.2
通讯作者：
Häussermann V
中科院分区：
文献类型：
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作者：
Pryer HV;Hawkings JR;Wadham JL;Robinson LF;Hendry KR;Hatton JE;Kellerman AM;Bertrand S;Gill-Olivas B;Marshall MG;Brooker RA;Daneri G;Häussermann V
冰川环境被认为是生物可利用营养物质的重要来源，冰川融水的输入可能会影响下游生态系统的生产力。然而，目前尚不清楚河流营养物浓度在一系列冰川覆盖范围内如何变化，这使得准确预测随着冰川持续退缩，陆地通量将如何变化变得具有挑战性。我们利用智利巴塔哥尼亚的 40 条河流作为独特的自然实验室，研究冰川覆盖如何影响河流的硅和铁浓度，并推断这些生物必需营养素的出口未来可能如何变化。在冰川供水的河流中，溶解的硅（硅酸）和可溶的铁（0.02米）浓度相对较低，而胶体纳米颗粒（0.02-0.45米）硅和铁的浓度随着冰川覆盖的变化而显着增加。这些胶体纳米颗粒相主要由铝硅酸盐和铁羟基氧化物组成，突出表明需要进行尺寸分级分析和进一步研究以量化胶体纳米颗粒物质的不稳定性。我们还证明了硅和铁的活性颗粒（0.45米）相的重要性，它们通常不计入陆地养分预算，但可以主导河流出口。溶解硅和可溶铁产量估计值没有显示出冰川覆盖的趋势，表明随着冰川的持续退缩，总出口量没有显着变化。然而，在高度冰川化的流域中，胶体纳米颗粒和活性沉积物结合的硅和铁的产量要高出一个数量级，并且与冰川覆盖呈显着的正相关。因此，随着智利巴塔哥尼亚冰川覆盖的消失，这些阶段的区域规模出口可能会减少，并对下游生态系统产生潜在影响。智利巴塔哥尼亚 40 条河流的硅和铁浓度揭示了冰川覆盖对陆地养分循环的影响 硅和铁的胶体和活性颗粒相在冰川供水的河流中升高，并主导出口预算随着冰川的持续退缩，河流硅和铁的出口可能会发生显着变化，这可能会影响下游生态系统的生产力
Glaciated environments have been highlighted as important sources of bioavailable nutrients, with inputs of glacial meltwater potentially influencing productivity in downstream ecosystems. However, it is currently unclear how riverine nutrient concentrations vary across a spectrum of glacial cover, making it challenging to accurately predict how terrestrial fluxes will change with continued glacial retreat. Using 40 rivers in Chilean Patagonia as a unique natural laboratory, we investigate how glacial cover affects riverine Si and Fe concentrations, and infer how exports of these bioessential nutrients may change in the future. Dissolved Si (as silicic acid) and soluble Fe (0.02 m) concentrations were relatively low in glacier‐fed rivers, whereas concentrations of colloidal‐nanoparticulate (0.02–0.45 m) Si and Fe increased significantly as a function of glacial cover. These colloidal‐nanoparticulate phases were predominately composed of aluminosilicates and Fe‐oxyhydroxides, highlighting the need for size‐fractionated analyses and further research to quantify the lability of colloidal‐nanoparticulate species. We also demonstrate the importance of reactive particulate (0.45 m) phases of both Si and Fe, which are not typically accounted for in terrestrial nutrient budgets but can dominate riverine exports. Dissolved Si and soluble Fe yield estimates showed no trend with glacial cover, suggesting no significant change in total exports with continued glacial retreat. However, yields of colloidal‐nanoparticulate and reactive sediment‐bound Si and Fe were an order of magnitude greater in highly glaciated catchments and showed significant positive correlations with glacial cover. As such, regional‐scale exports of these phases are likely to decrease as glacial cover disappears across Chilean Patagonia, with potential implications for downstream ecosystems. Si and Fe concentrations from 40 rivers in Chilean Patagonia reveal the impact of glacial cover on terrestrial nutrient cycling Colloidal and reactive particulate phases of Si and Fe are elevated in glacier‐fed rivers and dominate export budgets Riverine exports of Si and Fe are likely to significantly change with continued glacial retreat, which may impact productivity in downstream ecosystems