title: Influence of seawater intrusion on microbial communities in groundwater.
abstract: Groundwater is the sole source of potable water on Jeju Island in the Republic of (South) Korea. Groundwater is also used for irrigation and industrial purposes, and it is severely impacted by seawater intrusion in coastal areas. Consequently, monitoring the intrusion of seawater into groundwater on Jeju is very important for health and environmental reasons. A number of studies have used hydrological models to predict the deterioration of groundwater quality caused by seawater intrusion. However, there is conflicting evidence of intrusion due to complicated environmental influences on groundwater quality. Here we investigated the use of next generation sequencing (NGS)-based microbial community analysis as a way to monitor groundwater quality and detect seawater intrusion. Pristine groundwater, groundwater from three coastal areas, and seawater were compared. Analysis of the distribution of bacterial species clearly indicated that the high and low salinity groundwater differed significantly with respect to microbial composition. While members of the family Parvularculaceae were only identified in high salinity water samples, a greater percentage of the phylum Actinobacteria was predominantly observed in pristine groundwater. In addition, we identified 48 shared operational taxonomic units (OTUs) with seawater, among which the high salinity groundwater sample shared a greater number of bacterial species with seawater (6.7%). In contrast, other groundwater samples shared less than 0.5%. Our results suggest that NGS-based microbial community analysis of groundwater may be a useful tool for monitoring groundwater quality and detect seawater intrusion. This technology may also provide additional insights in understanding hydrological dynamics.
authors.affiliation: Faculty of Biotechnology, College of Applied Life Sciences, SARI, Jeju National University, Jeju 690-756, Republic of Korea. Electronic address: tatsu@jejunu.ac.kr.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Unno
authors.affiliation: Faculty of Biotechnology, College of Applied Life Sciences, SARI, Jeju National University, Jeju 690-756, Republic of Korea.
authors.forename: Jungman
authors.initials: J
authors.lastname: Kim
authors.affiliation: Faculty of Biotechnology, College of Applied Life Sciences, SARI, Jeju National University, Jeju 690-756, Republic of Korea.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Faculty of Biotechnology, College of Applied Life Sciences, SARI, Jeju National University, Jeju 690-756, Republic of Korea; Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Viet Nam.
authors.forename: Son G
authors.initials: SG
authors.lastname: Nguyen
authors.affiliation: Faculty of Biotechnology, College of Applied Life Sciences, SARI, Jeju National University, Jeju 690-756, Republic of Korea.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Guevarra
authors.affiliation: Jeju Water Resources Headquarters, Jeju 695-962, Republic of Korea.
authors.forename: Gee Pyo
authors.initials: GP
authors.lastname: Kim
authors.affiliation: Department of Bioenvironmental Chemistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Soil, Water, and Climate, BioTechnology Institute, University of Minnesota, St. Paul, MN 55108, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sadowsky
mesh_terms: D004784:Environmental Monitoring; D060587:Groundwater / Q000737:chemistry / Q000382:microbiology*; D062070:Hydrology; D056910:Republic of Korea; D054712:Salinity; D012623:Seawater / Q000032:analysis*
keywords: 16S rRNA gene; Freshwater quality; Microbial community; Seawater intrusion