Niche Differentiation of Active Methane-Oxidizing Bacteria in Estuarine Mangrove Forest Soils in Taiwan

Abstract

Mangrove forests are one of the important ecosystems in tropical coasts because of their high primary production, which they sustain by sequestering a substantial amount of CO2 into plant biomass. These forests often experience various levels of inundation and play an important role in CH4 emissions, but the taxonomy of methanotrophs in these systems remains poorly understood. In this study, DNA-based stable isotope probing showed significant niche differentiation in active aerobic methanotrophs in response to niche differentiation in upstream and downstream mangrove soils of the Tamsui estuary in northwestern Taiwan, in which salinity levels differ between winter and summer. Methylobacter and Methylomicrobium-like Type I methanotrophs dominated methane-oxidizing communities in the field conditions and were significantly 13C-labeled in both upstream and downstream sites, while Methylobacter were well adapted to high salinity and low temperature. The Type II methanotroph Methylocystis comprised only 10–15% of all the methane oxidizers in the upstream site but less than 5% at the downstream site under field conditions. 13C-DNA levels in Methylocystis were significantly lower than those in Type I methanotrophs, while phylogenetic analysis further revealed the presence of novel methane oxidizers that are phylogenetically distantly related to Type Ia in fresh and incubated soils at a downstream site. These results suggest that Type I methanotrophs display niche differentiation associated with environmental differences between upstream and downstream mangrove soils.

Salinidade E Disponibilidade De Substratos: Implicações Sobre a Atividade Metanogênica Em Duas Lagoas Costeiras Do Norte Fluminense

“…Deve-se destacar os efeitos da salinidade sobre a oxidação do metano, ou metanotrofia, pois a emissão de metano está associada ao saldo entre os processos de produção e oxidação do gás. Alguns estudos destacam esta influência em mangues e regiões estuarinas (Ho et al 2018, Osudar et al 2017, Shiau et al 2020. Os resultados apontam para diferentes respostas quanto à metanotrofia com relação à concentração de NaCl.…”

Dissolved greenhouse gases and benthic microbial communities in coastal wetlands of the Chilean coast semiarid region

“…For instance, Nitrosomonas dominated the freshwater areas compared to Nitrosospira which was more abundant in brackish water of the Ythan estuary (Scotland) [ 60 ]. Previous research has documented that the abundance of other methanotrophic species, such as Methylomirabilis oxifera and Methylocystis sp., decreased in areas with higher salinity of coastal wetlands [ 61 , 62 ].…”

Dynamics of Methane in Mangrove Forest: Will It Worsen with Decreasing Mangrove Forests?

“…Methanotrophs exist under both aerobic and anaerobic conditions. Aerobic methanotrophs are phylogenetically divided into two main groups: type I (Gammaproteobacteria, e.g., Methylococcaceae) and type II (Alphaproteobacteria, e.g., Methylocystaceae) [86][87][88][89], nitrate-or nitrite-dependent [90,91] and metal-dependent [92] CH 4 oxidizers, respectively. Type I methanotrophs tend to be dominant in natural environments with sufficient nutrients and substrates (i.e., relatively high O 2 concentration, low CH 4 concentration) [39,58,93], whereas type II methanotrophs tend to be abundant in resource-limited environments with a high affinity for their nutrients and substrates (i.e., relatively low O 2 concentration, high CH 4 concentration) [84,87,94,95].…”