Bacteria increase arid-land soil surface temperature through the production of sunscreens.
Bacteria increase arid-land soil surface temperature through the production of sunscreens.
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DOI：
10.1038/ncomms10373
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发表时间：
2016-01-20
影响因子：
16.6
通讯作者：
Garcia-Pichel F
中科院分区：
文献类型：
--
作者：
Couradeau E;Karaoz U;Lim HC;Nunes da Rocha U;Northen T;Brodie E;Garcia-Pichel F
土壤表面温度是陆地生物地球化学过程的重要驱动因素，它强烈依赖于土壤反照率，而反照率可以被植物覆盖等因素显著地改变。在植被稀疏的土地上，土壤表面可以被光合微生物定植，这些微生物可以建立生物结壳群落。在这里，我们同时使用物理、生化和微生物分析来表明，成熟的生物外壳可以通过积累大量的次生代谢物——微生物防晒丝胞胺（由一组晚期演替蓝藻产生），使地表土壤温度升高10°C。胞丝蛋白积累显著降低土壤反照率。这种局部变暖对土壤微生物群有明显而直接的影响，导致热敏细菌物种被更耐热的形式所取代。这些结果表明，植被和微生物都是改变陆地反照率的一个因素，可能影响生物圈对过去和未来气候的反馈，并呼吁在更大尺度上直接评估这种影响。土壤表面温度影响着许多生物地球化学过程，它取决于土壤反照率。在这里，Couradeau等人表明，一些蓝藻可以通过积累防晒代谢物将干旱土地土壤表面的温度提高10°C。
Soil surface temperature, an important driver of terrestrial biogeochemical processes, depends strongly on soil albedo, which can be significantly modified by factors such as plant cover. In sparsely vegetated lands, the soil surface can be colonized by photosynthetic microbes that build biocrust communities. Here we use concurrent physical, biochemical and microbiological analyses to show that mature biocrusts can increase surface soil temperature by as much as 10 °C through the accumulation of large quantities of a secondary metabolite, the microbial sunscreen scytonemin, produced by a group of late-successional cyanobacteria. Scytonemin accumulation decreases soil albedo significantly. Such localized warming has apparent and immediate consequences for the soil microbiome, inducing the replacement of thermosensitive bacterial species with more thermotolerant forms. These results reveal that not only vegetation but also microorganisms are a factor in modifying terrestrial albedo, potentially impacting biosphere feedbacks on past and future climate, and call for a direct assessment of such effects at larger scales. Soil surface temperature, which affects many biogeochemical processes, depends on soil albedo. Here, Couradeau et al. show that some cyanobacteria can increase the temperature of arid-land soil surface by as much as 10 °C through the accumulation of a sunscreen metabolite.