The Greenland Ice Sheet as a hot spot of phosphorus weathering and export in the Arctic
The Greenland Ice Sheet as a hot spot of phosphorus weathering and export in the Arctic
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DOI：
10.1002/2015gb005237
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发表时间：
2016-02-01
影响因子：
5.2
通讯作者：
Nienow, Peter
中科院分区：
文献类型：
--
作者：
Hawkings, Jon;Wadham, Jemma;Nienow, Peter
由于缺乏现场数据，冰盖对全球磷生物地球化学循环的贡献在很大程度上尚不清楚。在这里，我们首次对格陵兰冰盖冰川的磷输出进行了全面研究。我们的研究结果表明，冰盖是北极磷输出的热点地区。可溶性活性磷 (SRP) 浓度高达 0.35 μM，与北极河流中观察到的浓度相似。 SRP的产量是文献中最高的，剥蚀率为17-27kgPkm(-2)yr(-1)。与非冰川流域一样，颗粒相主导磷输出（> 总磷通量的 97%）。研究的两个冰川之间的不稳定颗粒部分有所不同，较大冰川的产量显着更高（57.3 vs 8.3kgPkm(-2)yr(-1)）。总磷产量比文献报道的河流值高一个数量级。我们估计，冰盖贡献了北冰洋生物可利用磷总量的 15%（相当于 11Ggyr(-1)），并且在总磷输入量（408Ggyr(-1)）中占主导地位，是北极河流估计磷输入量（126Ggyr(-1)）的 3 倍多。我们预测，未来这些通量将随着冰盖淡水排放量的增加而增加。
The contribution of ice sheets to the global biogeochemical cycle of phosphorus is largely unknown, due to the lack of field data. Here we present the first comprehensive study of phosphorus export from two Greenland Ice Sheet glaciers. Our results indicate that the ice sheet is a hot spot of phosphorus export in the Arctic. Soluble reactive phosphorus (SRP) concentrations, up to 0.35 mu M, are similar to those observed in Arctic rivers. Yields of SRP are among the highest in the literature, with denudation rates of 17-27kgPkm(-2)yr(-1). Particulate phases, as with nonglaciated catchments, dominate phosphorus export (>97% of total phosphorus flux). The labile particulate fraction differs between the two glaciers studied, with significantly higher yields found at the larger glacier (57.3 versus 8.3kgPkm(-2)yr(-1)). Total phosphorus yields are an order of magnitude higher than riverine values reported in the literature. We estimate that the ice sheet contributes similar to 15% of total bioavailable phosphorus input to the Arctic oceans (similar to 11Ggyr(-1)) and dominates total phosphorus input (408Ggyr(-1)), which is more than 3 times that estimated from Arctic rivers (126Ggyr(-1)). We predict that these fluxes will rise with increasing ice sheet freshwater discharge in the future.