[A-HW20] 流域の物質輸送と栄養塩循環－人間活動および気候変動の影響－

[AHW20-11] The examination of environmental factors on the community composition of riverine bacteria and microalgae in an epilithon during irrigation season in the Yasu River, Japan

*池谷 透¹、石田 卓也¹、上原 佳敏¹、淺野 悟史²、奥田 昇¹、潮 雅之^3,4、藤永 承平³、小林 由紀⁵、Chia-Ying Ko⁶、Elfritzson Peralta⁷、陀安 一郎¹、岩田 智也⁸ (1.総合地球環境学研究所、2.滋賀県琵琶湖環境科学研究センター、3.京都大学生態学研究センター、4.さきがけ 科学技術振興機構、5.山口大学大学院医学系研究科、6.国立台湾大学、7.サント・トマス大学、8.山梨大学生命環境学部)

キーワード：バクテリア、微細藻類、16S、次世代シーケンサー

We analyzed the composition of bacteria and microalgae which were collected at the 29 sampling sites at the Yasu River in late spring, 2016, in order to assess the possible effect of anthropogenic effect of land use on the microflora of epilithic communities. The analyses were made with MiSeq 16S rRNA gene sequencing and cell counting for the bacteria and microalgae, respectively. A control data set was obtained at the same sampling sites at the Yasu River in 2012 to elucidate the general and seasonal dynamics of the microbial and algal communities.
The previous examination has shown that both the microbial and algal communities in the Yasu River watershed during irrigation season showed site-specific differences. 1) The important environmental gradients for microbial communities may be formed by land use. 2) The important parameters were temperature, DOC, current, and PP of EOM. 3) The spatial pattern of phycobilin occurrence was consistent to the β diversity deduced from algal counts and metagenomics. The further analyses of the bacterial and algal taxa have shown site-specific occurrence of particular groups during irrigation season, which suggest that particular functional groups determined the spatial pattern of species diversity in response to the environmental factors, such as nutrient, temperature and turbidity.