Response of Antarctic cryoconite microbial communities to light.
Response of Antarctic cryoconite microbial communities to light.
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DOI：
10.1093/femsec/fiw076
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发表时间：
2016-06
影响因子：
4.2
通讯作者：
Dubnick A
中科院分区：
文献类型：
--
作者：
Bagshaw EA;Wadham JL;Tranter M;Perkins R;Morgan A;Williamson CJ;Fountain AG;Fitzsimons S;Dubnick A
极地冰川表面的微生物群落被发现分散在冰面上，或集中在冰孔和冰湖中，这些冰孔和冰湖是一层冰层覆盖的碎片的积累，全年或全年都有。冰盖限制了光合有效辐射（PAR）对沉积物层的渗透，因为冰衰减了高达99%的入射辐射。这一系列的野外和室内试验表明，PAR是冰晶和冰湖生态系统初级生产的重要控制因素。增加光照强度提高了受控实验室孵育来自南极洲麦克默多干谷乔伊斯冰川表面的碎片的初级生产效率。然而，当光强增加到接近冰表面的水平时，没有冰盖的保护，效率下降，光生理测量表明群落遭受光胁迫。因此，这些群落很好地适应了低光照水平。与北极冰锥菌群落相比，北极冰锥菌群落在大部分消融季节通常没有被冰盖覆盖，这表明这些生物也受到强光的胁迫，因此它们必须采取措施防止光损伤。南极冰川上的冰晶洞和冰湖中的微生物群落适应低光照水平，当暴露在强光下时表现出压力。
Microbial communities on polar glacier surfaces are found dispersed on the ice surface, or concentrated in cryoconite holes and cryolakes, which are accumulations of debris covered by a layer of ice for some or all of the year. The ice lid limits the penetration of photosynthetically available radiation (PAR) to the sediment layer, since the ice attenuates up to 99% of incoming radiation. This suite of field and laboratory experiments demonstrates that PAR is an important control on primary production in cryoconite and cryolake ecosystems. Increased light intensity increased efficiency of primary production in controlled laboratory incubations of debris from the surface of Joyce Glacier, McMurdo Dry Valleys, Antarctica. However, when light intensity was increased to levels near that received on the ice surface, without the protection of an ice lid, efficiency decreased and measurements of photophysiology showed that the communities suffered light stress. The communities are therefore well adapted to low light levels. Comparison with Arctic cryoconite communities, which are typically not covered by an ice lid for the majority of the ablation season, showed that these organisms were also stressed by high light, so they must employ strategies to protect against photodamage. Microbial communities in cryoconite holes and cryolakes on glaciers in Antarctica are adapted to low light levels and exhibit stress when exposed to high light.