Response of the methanogenic microbial communities in A mazonian oxbow lake sediments to desiccation stress

作者：Ralf Conrad, Yang Ji, Matthias Noll, Melanie Klose, Peter Claus, Alex Enrich‐Prast · 发表于：Environmental Microbiology · 年份：2013 · DOI：10.1111/1462-2920.12267 · 被引用次数：71 · 研究领域：Methane Hydrates and Related Phenomena、Microbial Community Ecology and Physiology、Anaerobic Digestion and Biogas Production

Methanogenic microbial communities in soil and sediment function only when the environment is inundated and anoxic. In contrast to submerged soils, desiccation of lake sediments happens only rarely. However, some predictions suggest that extreme events of drying will become more common in the Amazon region, and this will promote an increase in sediments drying and exposure. We asked whether and how such methanogenic communities can withstand desiccation stress. Therefore, we determined the rates and pathways of CH(4) production (analysis of CH(4) and δ(13) C of CH(4), CO(2) and acetate), the copy numbers of bacterial and archaeal 16S rRNA genes and mcrA genes (quantitative PCR), and the community composition of Archaea and Bacteria (T-RFLP and pyrosequencing) in oxbow lake sediments of rivers in the Brazilian Amazon region. The rivers were of white water, black water and clear water type. The measurements were done with sediment in fresh state and after drying and rewetting. After desiccation and rewetting the composition of both, the archaeal and bacterial community changed. Since lake sediments from white water rivers exhibited only negligible methanogenic activity, probably because of relatively high iron and low organic matter content, they were not further analysed. The other sediments produced CH(4), with hydrogenotrophic methanogenesis usually accounting for > 50% of total activity. After desiccation and rewetting, archaeal and bacterial gene copy numbers decreased. Th...