Microbial diversity in alpine tundra wet meadow soil: novel Chloroflexi from a cold, water-saturated environment
Microbial diversity in alpine tundra wet meadow soil: novel Chloroflexi from a cold, water-saturated environment
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DOI：
10.1111/j.1462-2920.2006.01041.x
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发表时间：
2006-08-01
影响因子：
5.1
通讯作者：
Schmidt, Steven K.
中科院分区：
文献类型：
--
作者：
Costello, Elizabeth K.;Schmidt, Steven K.
寒冷、水饱和的土壤发挥着重要的生物地球化学作用，但对在这种条件下活跃的微生物的身份和栖息地几乎一无所知。我们调查了全年的微环境的高山冻原湿草甸土壤在科罗拉多落基山脉，重点是春季融雪的土壤地球化学和微生物多样性-高山生态系统的动态时间。现场测量显示，春季和秋季的长期温度稳定在0摄氏度附近，深层土壤（30厘米）比表层土壤更稳定，夏季和冬季更温和，等温期更长。土壤是饱和的，水的可用性受到冷冻而不是干燥的限制。生物可利用的氧化还原物种的分析表明，从锰还原净铁还原在2-3厘米的深度，升高SO 42-和减少可溶性锌在春季融雪。末端限制性片段长度多态性谱检测到细菌群落组成在表面到表面下的过渡相关的转变。从沿着深度剖面汇集的饱和春季土壤DNA中扩增细菌和古细菌小亚基rRNA基因。这些次表面偏向文库的最显着的特点是高相对丰度的新的，未培养的Chloroflexi相关序列，包括采样的第三大细菌部门，并代表七个新的Chloroflexi亚部门，从而大大扩大了已知的多样性，这种细菌部门。我们认为，这些新的Chloroflexi是活跃在近0摄氏度的温度下，在可能的缺氧条件下，并利用地球化学输入，如硫化物上坡风化。
Cold, water-saturated soils play important biogeochemical roles, yet almost nothing is known about the identity and habitat of microbes active under such conditions. We investigated the year-round microenvironment of an alpine tundra wet meadow soil in the Colorado Rocky Mountains, focusing on the biogeochemistry and microbial diversity of spring snowmelt - a dynamic time for alpine ecosystems. In situ measurements revealed spring and autumn periods of long-term temperature stability near 0 degrees C, and that deeper soil (30 cm) was more stable than surface soil, with more moderate summers and winters, and longer isothermal phases. The soil was saturated and water availability was limited by freezing rather than drying. Analyses of bioavailable redox species showed a shift from Mn reduction to net Fe reduction at 2-3 cm depth, elevated SO42- and decreased soluble Zn at spring snowmelt. Terminal restriction fragment length polymorphism profiles detected a correlated shift in bacterial community composition at the surface to subsurface transition. Bacterial and archaeal small-subunit rRNA genes were amplified from saturated spring soil DNA pooled along a depth profile. The most remarkable feature of these subsurface-biased libraries was the high relative abundance of novel, uncultivated Chloroflexi-related sequences comprising the third largest bacterial division sampled, and representing seven new Chloroflexi subdivisions, thereby dramatically expanding the known diversity of this bacterial division. We suggest that these novel Chloroflexi are active at near -0 degrees C temperatures, under likely anoxic conditions, and utilize geochemical inputs such as sulfide from upslope weathering.