黑龙江林甸地热田热水微生物多样性与群落结构分析

Analysis of microbial diversity and community structure in thermal waters from Lindian geothermal field,Heilongjiang Province

【研究目的】研究地热系统微生物群落组成有助于揭示地热流体地球化学演化和指示热储地球化学环境。已有研究显示,林甸地热田热水还原性强且富含甲烷,但关于微生物在甲烷形成中的作用研究较少。本文旨在分析林甸地热田热水中微生物的群落结构和多样性特征,并揭示其甲烷生成途径。【研究方法】在地热供暖季和非供暖季采集并测试了9个热水微生物样品,并对热水中微生物多样性、群落结构及功能基因进行了分析。【研究结果】属水平上,林甸地热水中优势细菌主要为不动杆菌属(Acinetobacter,>80%),与已有报道的地热系统有一定差异,而同油田热水相似;供暖季和非供暖季热水中细菌多样性差异较大,非供暖季细菌多样性高于供暖季,但古菌多样性基本不受开采影响;优势古菌以广古菌门(Euryarchaeota)产甲烷菌为主,地热流体中的甲烷气体主要源于H_(2)还原CO_(2)产甲烷途径,而甲基歧化产甲烷作用和H_(2)还原甲基化合物产甲烷途径次之。【结论】林甸地热田热水中微生物多样性和群落结构较为独特,与地层中有机质含量较高、地热开采扰动有关。

This paper is the result of geothermal survey engineering.[Objective]Researches on microbial community in geothermal systems is key to indicate geochemical environment and evolution of thermal fluids.Previous researches have shown that the thermal water in Lindian geothermal field is highly reducing and is rich in methane.The objective of this paper is to characterize the microbial diversity and community structure of the thermal water.[Methods]A total of 9 thermal water samples were collected and tested during exploitation and non-exploitation periods,and the microbial diversity,community structure and functional genes of the samples were analyzed.[Results]The dominant bacterial genera in the thermal water is mainly Acinetobacter,which is different from most geothermal systems reported,but are similar to that of oil fields.The bacterial diversity of the thermal waters during the exploitation period and the non-exploitation period is significantly different,i.e.,the bacterial diversity in the non-exploitation period is higher than that in the exploitation period,while the archaeal diversity is not affected significantly by exploitation.The dominant archaea are mainly Euryarchaeota methanogens.Functional gene prediction of archaea shows that methane production in Lindian geothermal field is dominated by hydrogenotrophic methanogenesis,and secondarily by disproportionation of methyl groups and reduction of methyl compounds with H_(2).[Conclusions]The microbial diversity and community structure of the thermal waters from Lindian geothermal field is relatively unique,which is related to the high content of organic matters and thermal water exploitation.