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Aerobic and anaerobic methanotrophic communities in urban landscape wetland

Chen, Sili, Chen, Jianfei, Chang, Sha, Yi, Hao, Huang, Dawei, Xie, Shuguang, Guo, Qingwei
Applied microbiology and biotechnology 2018 v.102 no.1 pp. 433-445
Methylocystis, constructed wetlands, genes, landscapes, methane, methanotrophs, nitrogen content, organic carbon, oxidation, ribosomal RNA, sediments, urban areas, vegetation types
Both aerobic methane-oxidizing bacteria (MOB) and nitrite-dependent anaerobic methane oxidation (n-damo) organisms can be important methane sinks in a wetland. However, the influences of the vegetation type on aerobic MOB and n-damo communities in wetland, especially in constructed wetland, remain poorly understood. The present study investigated the influences of the vegetation type on both aerobic MOB and n-damo organisms in a constructed urban landscape wetland. Sediments were collected from eight sites vegetated with different plant species. The abundance (1.19–3.27 × 10⁷ pmoA gene copies per gram dry sediment), richness (Chao1 estimator = 16.3–81.5), diversity (Shannon index = 2.10–3.15), and structure of the sediment aerobic MOB community were found to vary considerably with sampling site. In contrast, n-damo community abundance (8.74 × 10⁵–4.80 × 10⁶ NC10 16S rRNA gene copies per gram dry sediment) changed slightly with the sampling site. The richness (Chao1 estimator = 1–11), diversity (Shannon index = 0–0.78), and structure of the NC10 16S rRNA gene-based n-damo community illustrated slight site-related changes, while the spatial changes of the pmoA gene-based n-damo community richness (Chao1 estimator = 1–8), diversity (Shannon index = 0–0.99), and structure were considerable. The vegetation type could have a profound impact on the wetland aerobic MOB community and had a stronger influence on the pmoA-based n-damo community than on the NC10 16S-based one in urban wetland. Moreover, the aerobic MOB community had greater abundance and higher richness and diversity than the n-damo community. Methylocystis (type II MOB) predominated in urban wetland, while no known type I MOB species was detected. In addition, the ratio of total organic carbon to total nitrogen (C/N) might be a determinant of sediment n-damo community diversity and aerobic MOB richness.