[A-HW22] Material transportation and cycling in watershed ecosystems; from headwaters to coastal areas

[AHW22-P21] Metagenomic analysis on the groundwater in the Ryukyu Limestone area

*Maruyama Rio¹, Nanami Mizusawa¹, Jun Yasumoto², Mariko Iijima³, Yasumoto Ko¹, Mina Hirose⁴, Akira Iguchi³, Mitsuru Jimbo¹, Shugo Watabe¹ (1.School of Marine Biosciences, Kitasto University, 2.Faculty of Agriculture, University of the Ryukyus, 3.National Institute of Advanced Industrial Science and Technology , 4.Tropical Technology Plus)

Keywords:metagenomic analisis, groundwater, okinawajima, Limestone area, Bacteria

While the microbial community has been considered to play an important role in organic matter decomposition and nutrient cycling in various ecosystems, our current understanding of the microbial community involved in groundwater ecosystem is strikingly insufficient. As a first step to evaluate the effect of the groundwater on coastal ecosystem, we performed metagenomic analysis on the groundwater of the Okinawajima in the southernmost region of Japan, along with measurement of environmental factors. Groundwater samples were collected from the Yaese Town characterized by high agricultural activities. Samples were filtered through 0.2 µm pore size filter and DNA were extracted from these filters using DNeasy PowerWater Kit (QIAGEN) for shotgun metagenomic analysis. The shotgun data of the groundwater showed that bacteria accounted for 93-98% of the total bacteria at the domain level for all the sampling locations, and Proteobacteria was most dominant at the phylum level, followed by Actinobacteria. Metagenomic analysis revealed the environmental parameters including Oxidation-reduction potential (ORP), Na, Fe and Pb were significantly correlated with certain microbial communities in the groundwater. Further studies are needed to elucidate how the bacterial communities are associated with organic matter decomposition and nutrient cycling in the groundwater and subsequent effects of its submarine discharge on coastal ecosystem.