School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Environ Microbiol. 2012 Sep;14(9):2272-82. doi: 10.1111/j.1462-2920.2012.02821.x. Epub 2012 Jul 11.
Drylands are the largest terrestrial biome on Earth and a ubiquitous feature is desert pavement terrain, comprising rocks embedded in the mineral soil surface. Quartz and other translucent rocks are common and microbial communities termed hypoliths develop as biofilms on their ventral surfaces. In extreme deserts these represent major concentrations of biomass, and are emerging as key to geobiological processes and soil stabilization. These highly specialized communities are dominated by cyanobacteria that support diverse heterotrophic assemblages. Here we identify global-scale trends in the ecology of hypoliths that are strongly related to climate, particularly with regard to shifts in cyanobacterial assemblages. A synthesis of available data revealed a linear trend for colonization with regard to climate, and we suggest potential application for hypoliths as 'biomarkers' of aridity on a landscape scale. The potential to exploit the soil-stabilizing properties of hypolithic colonization in environmental engineering on dryland soils is also discussed.
干旱地区是地球上最大的陆地生物群系，普遍存在的特征是沙漠铺砌地形，包括嵌入矿物土壤表面的岩石。石英和其他半透明岩石很常见，微生物群落被称为石内生物，在其腹面形成生物膜。在极端沙漠中，这些代表了生物量的主要集中地，并正在成为地球生物化学过程和土壤稳定的关键。这些高度专业化的群落主要由蓝藻组成，它们支持多样化的异养组合。在这里，我们确定了石内生物生态学的全球范围趋势，这些趋势与气候密切相关，特别是与蓝藻组合的变化有关。对现有数据的综合分析显示出与气候有关的定植线性趋势，我们建议将石内生物作为景观尺度干旱的“生物标志物”进行潜在应用。还讨论了在干旱地区土壤的环境工程中利用石内生物定植稳定土壤的特性的潜力。
