文章基本信息

标题：The structure, biological activity and biogeochemistry of cryoconite aggregates upon an Arctic valley glacier: Longyearbreen, Svalbard
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作者：Andy Hodson ; Karen Cameron ; Carl Bøggild 等
期刊名称：Journal of Glaciology
印刷版ISSN：0022-1430
电子版ISSN：1727-5652
出版年度：2010
卷号：56
期号：196
页码：349-362
DOI：10.3189/002214310791968403
出版社：Cambridge University Press
摘要：Glacier surfaces support unique microbial food webs dominated by organic and inorganic debris called ‘cryoconite’. Observations from Longyearbreen, Spitsbergen, show how these aggregate particles can develop an internal structure following the cementation of mineral grains (mostly quartz and dolomite) by filamentous microorganisms. Measurements of carbon and dissolved O 2 show that these microorganisms, mostly cyanobacteria, promote significant rates of photosynthesis (average 17 μgC g −1 d −1 ) which assist aggregate growth by increasing the biomass and producing glue-like extracellular polymeric substances. The primary production takes place not only upon the surface of the aggregates but also just beneath, due to the translucence of the quartz particles. However, since total photosynthesis is matched by respiration (average 19 μgC g −1 d −1 ), primary production does not contribute directly to cryoconite accumulation upon the glacier surface. The microorganisms therefore influence the surface albedo most by cementing dark particles and organic debris together, rather than simply growing over it. Time-lapse photographs show that cryoconite is likely to reside upon the glacier for years as a result of this aggregation. These observations therefore show that a better understanding of the relationship between supraglacial debris and ablation upon glaciers requires an appreciation of the biological processes that take place during summer.