Krausfeldt Lauren E, Tang Xiangming, van de Kamp Jodie, Gao Guang, Bodrossy Levente, Boyer Gregory L, Wilhelm Steven W
Department of Microbiology, The University of Tennessee, Knoxville, TN 37919, USA.
Taihu Laboratory for Lake Ecosystem Research, State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
FEMS Microbiol Ecol. 2017 Apr 1;93(4). doi: 10.1093/femsec/fix024.
Harmful cyanobacterial blooms (cyanoHABs) are a major threat to freshwater ecosystems worldwide. Evidence suggests that both nitrogen and phosphorus are important nutrients in the development and proliferation of blooms, yet much less is known about nitrogen cycling dynamics in these systems. To assess the potential nitrogen cycling function of the cyanoHAB community, surface water samples were collected in Lake Tai (Taihu), China over a 5-month bloom event in 2014. The expression of six nitrogen cycling genes (nifH, hzsA, nxrB, nrfA, amoA, nosZ) was surveyed using a targeted microarray with probes designed to provide phylogenetic information. N-Cycling gene expression varied spatially across Taihu, most notably near the mouth of the Dapu River. Expression of nifH was observed across the lake and attributable to both Proteobacteria and Cyanobacteria: Proteobacteria were major contributors to nifH signal near shore. Other N transformations such as anaerobic ammonia oxidation and denitrification were evident in the surface waters as well. Observations in this study highlight the potential importance of heterotrophic bacteria in N-cycling associated with cyanoHABs.
有害蓝藻水华（cyanoHABs）是全球淡水生态系统面临的主要威胁。有证据表明，氮和磷都是水华发生和扩散过程中的重要养分，但对于这些系统中氮循环动态的了解却少得多。为评估cyanoHAB群落潜在的氮循环功能，于2014年在中国太湖发生的一次为期5个月的水华事件期间采集了表层水样。使用带有旨在提供系统发育信息的探针的靶向微阵列，对六个氮循环基因（nifH、hzsA、nxrB、nrfA、amoA、nosZ）的表达进行了检测。太湖中氮循环基因的表达在空间上存在差异，最显著的是在大浦河口附近。整个湖泊均观察到nifH的表达，其来源既有变形菌门又有蓝细菌门：变形菌门是近岸nifH信号的主要贡献者。其他氮转化过程，如厌氧氨氧化和反硝化作用，在表层水体中也很明显。本研究中的观察结果突出了异养细菌在与cyanoHABs相关的氮循环中的潜在重要性。
