부산대학교 도서관

Microorganisms are important in soil development, inputs and biogeochemical cycling of nutrients and organic matter during early stages of ecosystem development, but little is known about their diversity, distribution, and function in relation to the chemical and physical changes associated with the progress of succession. In this study, we characterized the community structure and activity of nitrogen-fixing microbes during primary succession on a copper tailings. Terminal fragment length polymorphism ( T- RFLP) and clone sequencing of nifH genes indicated that different N2-fixing communities developed under primary succession. Phylogenetic analysis revealed a diversity of nifH sequences that were mostly novel, and many of these could be assigned to the taxonomic divisions P roteobacteria, C yanobacteria, and F irmicutes. Members of the C yanobacteria, mostly affiliated with Nostocales or not closely related to any known organisms, were detected exclusively in the biological soil crusts and represented a substantial fraction of the respective diazotrophic communities. Quantitative PCR (and statistical analyses) revealed that, overall, copy number of nifH sequences increased with progressing succession and correlated with changes in physiochemical properties (including elementary elements such as carbon and nitrogen) and the recorded nitrogenase activities of the tailings. Our study provides an initial insight into the biodiversity and community structure evolution of N2-fixing microorganisms in ecological succession of mine tailings. [ABSTRACT FROM AUTHOR]