Laboratoire Chrono-environnement, Université de Franche-Comté, UMR UFC/CNRS 6249 USC INRA, Montbéliard 25211 CEDEX, France.
Can J Microbiol. 2011 Mar;57(3):226-35. doi: 10.1139/W10-116.
Microbial communities living in Sphagnum are known to constitute early indicators of ecosystem disturbances, but little is known about their response (including their trophic relationships) to climate change. A microcosm experiment was designed to test the effects of a temperature gradient (15, 20, and 25°C) on microbial communities including different trophic groups (primary producers, decomposers, and unicellular predators) in Sphagnum segments (0-3 cm and 3-6 cm of the capitulum). Relationships between microbial communities and abiotic factors (pH, conductivity, temperature, and polyphenols) were also studied. The density and the biomass of testate amoebae in Sphagnum upper segments increased and their community structure changed in heated treatments. The biomass of testate amoebae was linked to the biomass of bacteria and to the total biomass of other groups added and, thus, suggests that indirect effects on the food web structure occurred. Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors. The sensitivity of these assemblages made them interesting indicators of climate change. Phenolic compounds represented an important explicative factor in microbial assemblages and outlined the potential direct and (or) indirect effects of phenolics on microbial communities.
生活在泥炭藓中的微生物群落被认为是生态系统干扰的早期指标，但人们对它们（包括其营养关系）对气候变化的反应知之甚少。本研究设计了一个微宇宙实验，以测试温度梯度（15、20 和 25°C）对包括不同营养类群（初级生产者、分解者和单细胞捕食者）在内的泥炭藓片段（帽状部的 0-3 cm 和 3-6 cm 处）中的微生物群落的影响。还研究了微生物群落与非生物因素（pH 值、电导率、温度和多酚）之间的关系。在加热处理中，泥炭藓上部段的有壳变形虫的密度和生物量增加，其群落结构发生变化。有壳变形虫的生物量与细菌的生物量以及其他添加组的总生物量相关，这表明食物网结构发生了间接影响。冗余分析表明，微生物组合在与非生物因素相关的温度梯度上，在泥炭藓上部段有很强的差异。这些组合的敏感性使它们成为气候变化的有趣指标。酚类化合物是微生物组合的一个重要解释因素，概述了酚类化合物对微生物群落的直接和（或）间接影响。
