Effect of environmental changes on diversity and functions of soil microbes in peat lands.

在沼泽中，植物残体在低温高湿条件下形成泥炭。有机物的分解速率非常低，并且取决于矿化速率，营养物质变得非常缓慢，纤维素分解细菌在其中发挥重要作用。在这样一个贫营养生态系统中，水分水平、矿物质供应、基质质量和其他影响分解速率的物理和化学因素最近被自然和人工源改变。本研究从日本三个地区不同地理类型的沼泽中分离出纤维素分解细菌，揭示其功能多样性，结果如下：从高原摩尔的泥炭藓垫中分离出的纤维素分解细菌主要为单细胞形成细菌，而从森林和芦苇沼泽的泥炭土中分离出的纤维素分解细菌数量较少，其中以放线菌为主。利用Biolog系统对分离的单细胞细菌进行碳底物利用模式的检测，并将其分为功能不同的类群。来自泥炭藓垫的分离物使用多种烃类和少量有机酸和氨基化合物作为碳底物，而来自森林泥炭土的分离物使用有限的烃类和某些羧酸和氨基化合物作为碳底物。这些结果可能反映了分离物所生活的湿地土壤中潜在碳基质的差异。

In mires, plant residues become into peat under low temperature and high moisture level condition. Decomposition rate of organic matter is very low and, and nutrients become available very slowly depending on the rate of mineralization, through which cellulose decomposing bacteria play an important roll. In such an oligotrophic ecosystem, moisture level, mineral supply, quality of substrate and other physical and chemical factors, which influence the decomposition rate, are changed recently by natural and artificial sources. In the present study, cellulose decomposing bacteria were isolated from geographically various type of mire in three areas in Japan, to reveal its functional diversity with following results :Mainly single cell forming bacteria was isolated from Sphagnum mat in highland moor, whereas small number of such bacteria was isolated from peat soil in forest and reed marsh, where mainly actinomycetes was dominant as cellulose decomposing bacteria. The isolated single cell bacteria were examined C-substrate utilization patterns by Biolog system and classified functionally different groups. Isolates from sphagnum mat used many kinds of hydrocarbons and small number of organic acids and amino compounds, whereas isolates from peat soil in a forest used limited hydrocarbons and some kinds of carboxylic acids and amino compounds as C-substrate. These results might reflect the difference of potential C-substrates in the habitats where the isolates living wetland soils.