High microbial activity on glaciers: importance to the global carbon cycle
High microbial activity on glaciers: importance to the global carbon cycle
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DOI：
10.1111/j.1365-2486.2008.01758.x
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发表时间：
2009-04-01
影响因子：
11.6
通讯作者：
Sattler, Birgit
中科院分区：
文献类型：
--
作者：
Anesio, Alexandre M.;Hodson, Andrew J.;Sattler, Birgit
冰晶洞可以覆盖冰川表面积的0.1-10%，是由太阳能加热的无机和有机碎屑融化成冰时在冰川表面形成的充满水的小洼地（通常直径小于1米，深度通常小于0.5米）。最近的研究表明，冰凝石被各种各样的微生物定植，包括病毒、细菌和藻类。冰川表面的微生物群落是在积极地影响生物地球化学循环，还是只是处于休眠状态，长期以来一直是一个有争议的问题。本文报道了斯瓦尔巴群岛、格陵兰岛和欧洲阿尔卑斯山脉冰川上冰晶洞的初级生产和群落呼吸。尽管最高温度很少超过0.1摄氏度，但低温结晶洞中的微生物活性很高。在夏季，低温结晶的原位初级生产和呼吸通常与温暖和营养丰富地区的土壤相当。仅考虑南极洲以外的冰川地区和冰川表面的保守平均冰凝石分布，我们发现在全球范围内，冰凝石孔每年有可能固定多达64 Gg的碳（即98 Gg的光合作用减去34 Gg的群落呼吸作用）。大多数湖泊和河流通常被认为是异养系统，但我们的研究结果表明，包含地球75%淡水的冰川在很大程度上是自养系统。
Cryoconite holes, which can cover 0.1-10% of the surface area of glaciers, are small, water-filled depressions (typically < 1 m in diameter and usually < 0.5 m deep) that form on the surface of glaciers when solar-heated inorganic and organic debris melts into the ice. Recent studies show that cryoconites are colonized by a diverse range of microorganisms, including viruses, bacteria and algae. Whether microbial communities on the surface of glaciers are actively influencing biogeochemical cycles or are just present in a dormant state has been a matter of debate for long time. Here, we report primary production and community respiration of cryoconite holes upon glaciers in Svalbard, Greenland and the European Alps. Microbial activity in cryoconite holes is high despite maximum temperatures seldom exceeding 0.1 degrees C. In situ primary production and respiration in cryoconites during the summer is often comparable with that found in soils in warmer and nutrient richer regions. Considering only glacier areas outside Antarctica and a conservative average cryoconite distribution on glacial surfaces, we found that on a global basis cryoconite holes have the potential to fix as much as 64 Gg of carbon per year (i.e. 98 Gg of photosynthesis minus 34 Gg of community respiration). Most lakes and rivers are generally considered as heterotrophic systems, but our results suggest that glaciers, which contain 75% of the freshwater of the planet, are largely autotrophic systems.