Department of Biology, University of York, York, North Yorkshire, UK
Department of Biology, University of York, York, North Yorkshire, UK.
J R Soc Interface. 2017 Dec;14(137). doi: 10.1098/rsif.2017.0729.
Concentrations of trace gases trapped in ice are considered to develop uniquely from direct snow/atmosphere interactions at the time of contact. This assumption relies upon limited or no biological, chemical or physical transformations occurring during transition from snow to firn to ice; a process that can take decades to complete. Here, we present the first evidence of environmental alteration due to microbial metabolism of trace gases (methyl halides and dimethyl sulfide) in polar snow. We collected evidence for ongoing microbial metabolism from an Arctic and an Antarctic location during different years. Methyl iodide production in the snowpack decreased significantly after exposure to enhanced UV radiation. Our results also show large variations in the production and consumption of other methyl halides, including methyl bromide and methyl chloride, used in climate interpretations. These results suggest that this long-neglected microbial activity could constitute a potential source of error in climate history interpretations, by introducing a so far unappreciated source of bias in the quantification of atmospheric-derived trace gases trapped within the polar ice caps.
被困在冰中的痕量气体的浓度被认为是在接触时直接通过雪-气相互作用而独特形成的。这一假设依赖于在从雪到粒雪再到冰的转变过程中几乎没有或没有发生生物、化学或物理转化；这个过程可能需要几十年才能完成。在这里，我们首次提供了由于痕量气体（甲基卤化物和二甲基硫）在极地雪中的微生物代谢导致环境变化的证据。我们在不同年份从北极和南极地点收集了正在进行的微生物代谢的证据。在暴露于增强的紫外线辐射后，雪层中的碘化甲基的生成量显著减少。我们的结果还表明，其他甲基卤化物（包括在气候解释中使用的甲基溴化物和一氯甲烷）的产生和消耗存在很大差异。这些结果表明，这种长期被忽视的微生物活动可能会导致在气候历史解释中引入一个潜在的误差源，因为它在极地冰盖内捕获的源自大气的痕量气体的量化中引入了一个迄今未被认识到的偏差源。
