A blue-ice ecosystem on the margin's of the East Antarctic ice sheet
A blue-ice ecosystem on the margin's of the East Antarctic ice sheet
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DOI：
10.3189/2013jog12j052
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发表时间：
2013-01-01
影响因子：
3.4
通讯作者：
Laybourn-Parry, Johanna
中科院分区：
文献类型：
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作者：
Hodson, Andy;Paterson, Harriet;Laybourn-Parry, Johanna
低温、干燥和强烈的太阳辐射使南极冰盖表面成为地球上最恶劣的栖息地之一。然而，我们在东南极洲Vestfold Hills地区的研究表明，微生物生产的有利条件已经在蓝冰区域的表面下建立起来，这些区域总共覆盖了约2%的冰盖外围。它们半透明的、被风打磨过的表面允许太阳能加热在深达1米的温室式环境中产生融水。在黑暗碎片颗粒或低温结晶周围，我们发现微生物活动最活跃，融化加剧。光合作用速率（平均2060 ng C （g cryoconite)）（-1） d(-1)）适应低光强度（类似于表面辐照值的10%），最可能由蓝藻和绿质体主导。异养细菌群落也被发现在冰晶中活跃，尽管平均细菌生长速率（5.7 ng C （g冰晶）（-1）d(-1)）远低于平均群落呼吸速率（1870 ng C （g冰晶）（-1）d(-1)）。大部分呼吸碳极有可能与自养生物和几种原生生物有关。因此，在地球上最冷的冰原周围，蓝冰区构成了微生物生命的绿洲。
Freezing temperatures, desiccation and high levels of solar radiation make the surface of the Antarctic ice sheet one of Earth's harshest habitats. However, our study in the Vestfold Hills area of East Antarctica shows that favourable conditions for microbial production become established just beneath the surface of blue-ice areas, which collectively cover about 2% of the ice-sheet periphery. Their translucent, wind-polished surface allows solar heating to create meltwater in a greenhouse-type environment at depths of up to 1 m. Melting is intensified around dark debris particles, or cryoconite, where we found microbiological activity to be greatest. Rates of photosynthesis (average 2060 ng C (g cryoconite)(-1) d(-1)) were adapted to low light intensities (similar to 10% of surface irradiance values) and most likely dominated by cyanobacteria and Chloroplastida. A heterotrophic bacterial community was also found to be active within the cryoconite, although average bacterial growth rates (5.7 ng C (g cryoconite)(-1) d(-1)) were far lower than average community respiration (1870 ng C (g cryoconite)(-1) d(-1)). The majority of the respired carbon was most likely associated with the autotrophs and several protists. Therefore, blue-ice areas constitute oases for microbial life around the periphery of Earth's coldest ice sheet.