Nitrogen loss by nirS-type denitrifying bacterial communities in eutrophic coastal sediments
Nitrogen loss by nirS-type denitrifying bacterial communities in eutrophic coastal sediments
复制标题
富营养化沿海沉积物中 nirS 型反硝化细菌群落的氮损失
DOI：
10.1016/j.ibiod.2020.104955
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发表时间：
2020-05-01
影响因子：
4.8
通讯作者：
Chang, Xiangyang
中科院分区：
文献类型：
--
作者：
Liu, Xiaohan;Wu, Jiapeng;Chang, Xiangyang
反硝化作用在不同生态系统中对活性无机氮的去除起着主导作用。本文对胶州湾沉积物中编码nirS的硝化细菌的活性、丰度和群落组成进行了研究。通过N-15添加和培养实验，测得表层沉积物的反硝化速率为0.18 ~ 9.97 nmol Ng（-1）h（-1），占总N-2产生量的81.45-99.93%，而估算的氮去除通量约为5.66 × 10（4）t Ny（-1）。此外，nirS基因的丰度范围为5.20 x 10（5）至3.01 x 10（8）拷贝/克。使用高通量测序技术靶向nirS基因，结果显示19个相似性为93%的优势OTU 5被分配到7个簇中。聚类2主要隶属于硫丝菌属，聚类4主要隶属于沃氏菌属，其他聚类与从几个沿海河口和海湾沉积物中获得的未培养的细菌相似。NH 4+和NO3-含量是影响JZB表层沉积物中浮游生物群落组成和分布的两个主要因素。总体而言，我们的研究结果表明，社区的nirS型硝化细菌具有多样性的组成，并可能高度有助于富营养化系统中的氮损失。
Denitrification plays a dominant role in the removal of reactive inorganic nitrogen species in different ecosystems. In this study, we investigated the activity, abundance, and community composition of nirS-encoding denitrifying bacteria from sediments of Jiaozhou Bay (JZB). The rates of denitrification, measured by N-15 amendment and incubation experiments, varied from 0.18 to 9.97 nmol N g(-1) h(-1) and contributed to 81.45-99.93% of the total N-2 production, while the estimated flux of nitrogen removal was about 5.66 x 10(4) t N y(-1) in surface sediments. Additionally, the abundance of nirS gene ranged from 5.20 x 10(5) to 3.01 x 10(8) copies per gram. High-throughput sequencing technique was used to target the nirS gene, which revealed 19 dominant OTU5 at 93% similarity that were assigned to 7 clusters. Cluster 2 was mainly affiliated to Thiothrix, while Cluster 4 was mainly affiliated to Woeseia and the other clusters were similar to uncultured denitrifiers obtained from sediments of several coastal estuaries and bays. NH4+ and NO3- contents were identified as the two main factors affecting community composition and distribution of denitrifiers among the surface sediments of JZB. Overall, our results showed that the community of nirS-type denitrifying bacteria had a diverse composition and could highly contribute to nitrogen loss in eutrophic systems.