1Ibaraki Univ. College of Agri., 2Grad. Sch. of Biotechnol., Universit. Gadjah Mada, Indonesia, 3, ,
Mt. Merapi is one of the most active volcanoes in Indonesia. Due to the 2010 eruption, the land around the mountain was covered by pyroclastic materials. For the environmental rehabilitation, it is important to know the pioneer soil microbial communities and their contribution to C and N accumulation and further to ecosystem development. The aim of this study was to analyze the early microbial communities, particularly the population density and compositions of N2-fixing bacteria, in the Mt. Merapi unvegetated volcanic deposits. Our investigation was designed to compare the microbial communities of the volcanic deposits with those of forest soil near the mountain by using molecular genetic approaches targeting bacterial 16S rRNA genes and nifH genes. Two unvegetated sites, BR and BRU, were established, together with a forest site (FR) as a reference. The microbial community composition was studied by T-RFLP profiling of the 16S rRNA genes. The NMDS ordination of the T-RFLP profiles showed a distinct clustering of the bacterial communities across the three sites. The diversity index were 3.11, 2.25, and 2.91 on sites BR, BRU, and FR, respectively, which indicated that the bacterial diversity was relatively higher in site BR than in the other sites. Clone library analysis of nifH genes is now in progress to analyze the compositions of N2-fixing bacteria.
keywords:volcanic deposit ,early ecosystem,early microbial community,,