Authors: HK Song S Sonkaria V Khare K Dong HT Lee SH Ahn HK Kim HJ Kang SH Lee S P Jung J M Adams
Publish Date: 2015/01/16
Volume: 70, Issue: 1, Pages: 168-174
Abstract
Formation of magnetite in anaerobic sediments is thought to be enhanced by the activities of ironreducing bacteria Geobacter has been implicated as playing a major role as in culture its cells are often associated with extracellular magnetite grains We studied the bacterial community associated with magnetite grains in sediment of a freshwater pond in South Korea Magnetite was isolated from the sediment using a magnet The magnetitedepleted fraction of sediment was also taken for comparison DNA was extracted from each set of samples followed by PCR for 16S bacterial ribosomal RNA rRNA gene and HiSeq sequencing The bacterial communities of the magnetiteenriched and magnetitedepleted fractions were significantly different The enrichment of three abundant operational taxonomic units OTUs suggests that they may either be dependent upon the magnetite grain environment or may be playing a role in magnetite formation The most abundant OTU in magnetiteenriched fractions was Geobacter bolstering the case that this genus is important in magnetite formation in natural systems Other major OTUs strongly associated with the magnetiteenriched fraction rather than the magnetitedepleted fraction include a Sulfuricella and a novel member of the Betaproteobacteria The existence of distinct bacterial communities associated with particular mineral grain types may also be an example of niche separation and coexistence in sediments and soils which cannot usually be detected due to difficulties in separating and concentrating minerals
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