COMPARISON OF MICROBIAL COMMUNITY STRUCTURE IN SURFACE SEDIMENTS OF SAROMA KO LAGOON WITH SETO INLAND SEA IN WINTER (16th Symposium on Polar Biology)

• Main Authors: / マツダ オサム, サコウ ヒロアキ, Narasimmalu RAJENDRAN, Osamu MATSUDA, Hiroaki SAKOH
• Format: Report
• Language: English
• Published: Proceeding 1995
• Subjects: Polar Biology; Proceedings of the NIPR Symposium on Polar Biology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=5256; http://id.nii.ac.jp/1291/00005256/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5256&item_no=1&attribute_id=18&file_no=1

Microbial community structure in surface sediments of Saroma Ko lagoon, as estimated by phospholipid ester-linked fatty acids (PLFA), has been compared with eutrophic bays (Osaka Bay and Hiroshima Bay) and a lake (Lake Kojima) in the Seto Inland Sea of Japan during winter. Sixty PLFAs were identified in sediments. The abundant PLFAs included 14:0, i15:0, 16:1d9c, 16:1d11, 16:0, 10Me16:0, a17:0, 18:1d9, 18:1d911, 18:0 and 20:5. Biomarker fatty acids of sulfate reducing bacteria (SRB) were also detected. High amounts of fatty acids in the range of 12-19 demonstrated that the prokaryotes were a significant component of sediment organic matter. The mean total PLFA concentration varied from 0.6 (Osaka Bay) to 28.6 μg/g dry weight of the sediment (Saroma Ko lagoon). High total PLFA concentration in the sediments of Saroma Ko lagoon indicated significantly high amounts of microbial biomass. From the presence of the bacterial biomarker fatty acids in sediments, the distribution of different microbial groups in sediments can be defined. In sedimentary microbial community structure of the study areas, the relative dominance of the microbial groups is in the following descending order: 1. Aerobic prokaryotes and eukaryotes, 2. Gram-positive bacteria and anaerobic bacteria, 3. SRB and other anaerobic bacteria, 4. Microeukaryotes. The aerobic prokaryotes and eukaryotes were dominantly present in Saroma Ko lagoon, whereas microeukaryotes, and gram-positive bacteria and anaerobic bacteria were abundantly present in Hiroshima Bay and Osaka Bay. The characteristic fatty acids of SRB and other anaerobic bacteria in Lake Kojima were higher than in other areas. The variation in the relative proportion of these microbial groups in sediments has been discussed in relation to the environmental conditions and pollution.