Cyanobacteria in Polar and Alpine Ecosystems
Cyanobacteria in Polar and Alpine Ecosystems
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DOI：
10.1007/978-3-319-57057-0_9
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发表时间：
2017
影响因子：
--
通讯作者：
A. Jungblut;W. Vincent
中科院分区：
文献类型：
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作者：
A. Jungblut;W. Vincent
蓝藻通常存在于极地和高山地区的淡水、土壤和冰川环境中。迄今为止的研究表明，这些冷居光养生物是耐冷的，而不是嗜冷的，其生长的最佳温度远高于其周围环境的温度范围。蓝藻垫出现在湖泊，池塘和溪流的底部，以及冰川和冰架上的融水栖息地。它们可以积累大量的生物量储存，并可能占这种环境中生态系统总生产力的主要部分。已知这些底栖生物群落中的某些分类群会产生蓝藻毒素，包括微囊藻毒素。浮游蓝细菌在许多高纬度湖泊中也有发现，特别是picocyanobacteria，但它们在极地海洋中明显缺乏或代表性很差，可能是由于它们在极端寒冷中的生长速度最低。蓝细菌也出现在寒冷地区的各种非水生栖息地，包括岩石上和岩石内，并作为极地和高山沙漠土壤结皮的主要成分。一些蓝藻的固氮能力使它们对冰川退缩后新暴露的土壤的自然富集特别重要。在寒冷的生物圈中蓝藻生态类型的进化和生物地理学是基因组分析和极间比较的当前焦点，这些研究提供了关于微生物生态系统如何在早期地球上长时间的寒冷和冻结中生存的见解。
Cyanobacteria are commonly found in freshwaters, soils and glacial environments in polar and alpine regions. Studies to date indicate these cold-dwelling phototrophs are psychrotolerant rather than psychrophilic, with temperature optima for growth that lie well above the temperature ranges of their ambient environment. Cyanobacterial mats occur at the bottom of lakes, ponds and streams and within meltwater habitats on glaciers and ice shelves. They can accumulate large biomass stocks and may account for the dominant fraction of total ecosystem productivity in such environments. Certain taxa in these benthic communities are known to produce cyanotoxins, including microcystins. Planktonic cyanobacteria are also found in many high latitude lakes, specifically picocyanobacteria, but they are conspicuously absent or poorly represented in polar seas, probably as a result of their minimal growth rates in extreme cold. Cyanobacteria also occur in a variety of nonaquatic habitats in the cold regions, including on and within rocks, and as a major constituent of soil crusts in polar and alpine deserts. The nitrogen-fixing capabilities of some cyanobacteria make them especially important for the natural enrichment of soils that have been newly exposed after glacial retreat. The evolution and biogeography of cyanobacterial ecotypes in the cold biosphere is a current focus of genomic analysis and pole-to-pole comparisons, and these studies are providing insights into how microbial ecosystems survived prolonged periods of cold and freeze-up on early Earth.