The vertical and temporal distributions of sulfate-reducing bacteria in sediments of Lake Aha

The distribution of sulfate-reducing bacteria( SRB) in the sediments of Lake Aha was analyzed based on evaluation of the presence and quantity of six main groups of SRB in sediments collected during spring and autumn. The results show that four SRB groups( Desulfotomaculum,Desulfobulbus,Desulfococcus-Desulfonema-Desulfosarcina and Desulfovibrio- Desulfomicrobium) are present in autumn,while only three groups( Desulfotomaculum,Desulfobulbus and Desulfococcus- Desulfonema-Desulfosarcina) are detected in spring. Compared with the autumn of Lake Aha,sediments in spring have relatively high dissolved oxygen contents and low temperature,which may lead to the inactive status of Desulfovibrio-Desulfomicrobium in the sediments and then the Desulfovibrio-Desulfomicrobium is undetectable due to its low activity. The distribution of each SRB group is wider in sediments collected in autumn than in spring,and they show a greater overall presence and quantity in autumn than in spring. These findings indicate that the environmental conditions in autumn are more suitable for SRBs.