日本地球惑星科学連合2019年大会

講演情報

[J] ポスター発表

セッション記号 B (地球生命科学) » B-BG 地球生命科学・地圏生物圏相互作用

[B-BG02] 地球惑星科学と微生物生態学の接点

2019年5月28日(火) 13:45 〜 15:15 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:砂村 倫成(東京大学大学院理学系研究科地球惑星科学専攻)、諸野 祐樹(海洋研究開発機構高知コア研究所)、濱村 奈津子(九州大学)

[BBG02-P02] Exploring biogeographic patterns of marine planktonic cyanobacteria in coastal habitats- integrating uncultured and cultured approaches

*Punyasloke Bhadury1 (1.Integrative Taxonomy and Microbial Ecology Research Group, Centre for Climate and Environmental Studies, Indian Institute of Science Education and Research Kolkata)

キーワード:Coast, marine planktonic cyanobacteria, diversity, 16S rRNA

The structure of marine planktonic cyanobacterial communities in coastal habitats can strongly influence rates and fluxes of coastal carbon cycling. Biogeographic patterns of marine planktonic cyanobacterial assemblages were elucidated from four coastal habitats namely, Baltic Sea (BL), Monterey Bay (MB), South China Sea (SCS) and Sundarbans (SB) based on deep phylogeny of 16S rRNA sequences generated using next generation sequencing and Sanger sequencing approaches. Based on 16S rRNA phylogeny, four major taxonomic orders of marine planktonic cyanobacteria were recovered in varying proportions with several novel 16S rRNA sequences in each of the four targeted habitats. Members of the order Synechococcales were dominant in all the habitats (−94% sequences) while the orders Chroococcales and Oscillatoriales were only detected in SB and SCS, respectively. In the phylogenetic tree, Synechococcus-like sequences showed overwhelming dominance in SB and they were found in three other habitats. Prochlorococcus-like sequences were found in sizeable number in MB and SCS but were absent in SB and coastal BL. Synechococcus-like sequences were represented by three major marine clusters (5.1, 5.2, and 5.3). Three novel clades as part of Synechococcus cluster were detected only in SB and one novel clade in BL. These clades could have potential functional significance in coastal carbon cycling. Interestingly, cultured based approaches also revealed a new species of Synechococcus, Synechococcus moorigangaii from SB which has the ability to grow across a range of salinity and metabolize different forms of nitrogen as well as fix di-nitrogen. This reflects the potential vast unexplored functional diversity of marine planktonic cyanobacteria in coastal habitats which needs to be identified and can help towards understanding of export of carbon in coastal oceans. Overall the study has revealed that majority of the marine planktonic cyanobacterial OTUs were found to be exclusive to each habitat, whereas some were shared by two or more habitats based on beta-diversity analysis.