低温高海拔湖泊岸边带厌氧氨氧化菌的存在、生物多样性及活性——以天山天池为例

本文旨在通过聚合酶链反应PCR、构建克隆文库、15N同位素示踪等技术研究厌氧氨氧化细菌在以天山天池为代表的高海拔低温水生态系统中的存在、发生、活性及对氮循环的影响.通过定量PCR测得天山天池沉积物厌氧氨氧化菌的丰度为(2.93×105±0.25×105)copy/每克干沉积物土样,证明了存在有一定数量的厌氧氨氧化菌;在分别对厌氧氨氧化细菌的16S rRNA和hzs B功能基因构建克隆文库,并对阳性克隆进行生物多样性分析,发现天山天池沉积物中16S rRNA阳性克隆子均属于同一个独立操作单元,与已知的厌氧氨氧化菌的相似度高于99%;而hzs B功能基因克隆文库中,其生物多样性略高于16S rRNA文库.通过同位素示踪技术测得该样品的厌氧氨氧化速率为1.162 nmol·g-1·h-1,其对氮气生成的贡献率高达82%,远高于以往报道的淡水环境中厌氧氨氧化对氮气生成的贡献率.推断高海拔和低温等环境可能不是限制厌氧氨氧化细菌生长的关键因素.

The activity and diversity analysis of anaerobic ammonium oxidation bacteria in the littoral sediments of the Heavenly Lake

This paper aims to use molecular biology technique such as PCR technology, the clone libraries, isotope tracer to validate that anaerobic ammonium oxidation (anammox) bacteria can live in wetland ecosystems with high altitude and low temperature represented by Heavenly Lake, and we also analyzed its biological diversity. Through the construction of clone libraries for 16S rRNA and hzsB gene of anammox bacteria, we categorized and analyzed the positive clones. To 16S rRNA clone library, it was found that all of the positive clones in sediment of The Heavenly Lake, with a similarity higher than 99%; belongd to the same Operational Taxa Unit (OTU); while in the hzsB gene clone library, positive clones were classified into three OTUs, two of which belonged to genus Brocadia, and another between Brocadia and Jettenia, which was identical with the 16S rRNA library. Then through quantitative PCR and isotope tracing method, the abundance of anammox bacteria was measured to (2.93×10⁵±0.25×10⁵)copies per gram of dry sediment and the anammox rate is 1.162 nmol·g^-1·h^-1, 82% to N₂ production, respectively. This indicate that the high altitude and low temperature might not the critical factors which limited the growth of anammox bacteria, and the anammox bacteria may has a low biological diversity but high contribution to the N₂ production in the nature of the anaerobic environment.