Characterization of Microbial Community Structure in the Surface Sediment of Osaka Bay, Japan, by Phospholipid Fatty Acid Analysis

Abstract

Twenty-eight sediment samples collected from Osaka Bay, Japan, were analyzed for phospholipid esterlinked fatty acids (PLFA) to determine regional differences in microbial community structure of the bay. The abundance of three major groups of C10 to Clg PLFA (saturated, branched, and monounsaturated PLFA), which accounted for 84 to 97% of the total PLFA, indicated the predominance of prokaryotes in the sediment. The distribution of six clusters obtained by similarity analysis in the bay revealed a marked regional distribution in the PLFA profiles. Total PLFA concentrations (0.56 to 2.97 ,g/g [dry weight] of the sediment) in sediments also showed marked variation among the stations, with higher concentrations of total PLFA in the central part of the bay. The biomass, calculated on the basis of total PLFA concentration, ranged from 0.25 x 108 to 1.35 x 108 cells per g (dry weight) of the sediment. The relative dominance of microbial groups in sediments was described by using the reported bacterial biomarker fatty acids. Very small amounts of the characteristic PLFA of microeukaryotes in sediments indicated the restricted distribution of microeukaryotes. By examining the distribution of clusters and groups of microorganisms in the bay, there were two characteristics of the distribution pattern: (i) the predominance of anaerobic bacteria and gram-positive prokaryotes, characterized by the high proportions of branched PLFA in the eastern and northeastern sides of the bay, where the reported concentrations of pollutants were also high, and (ii) the predominance of aerobic prokaryotes and eukaryotes, except for a few stations, in the western and southwestern sides of the bay, as evidenced by the large amounts of monounsaturated PLFA. Such significant regional differences in microbial community structure of the bay indicate shifts in microbial community structure.

Benthic ecosystem functioning beneath fish farms in different hydrodynamic environments

“…The C-isotopic ratios were corrected for the single methyl group inserted during derivatization. Bacterial biomass was measured by GC-IRMS, and bacterial biomass was calculated as PLFA (iC 14:0 , iC 15:0 , aiC 15:0 , iC 16:0 , iC 17:0 , aiC 17:0 , cyclo C 19:0 , 10 Methyl-C 16:0 ) concentration (mmol) mL 21 sediment/(a 3 b), where a is the average PLFA concentration in bacteria of 0.056 g C PLFA g 21 biomass (Brinch-Iversen and King 1990), and b is the average fraction-specific bacterial PLFA encountered in sediment dominated by bacteria (0.29; calculated after Rajendran et al 1993Rajendran et al , 1994. The prefixes ''i'' and ''ai'' refer to ''iso'' and ''antiso,'' respectively.…”

Diversity and abundance of Gram positive bacteria in a tidal flat ecosystem

“…Quantitative studies on marine Gram positive bacteria are still scarce, but they have been detected as substantial components of bacterial communities in various marine sediments (Rajendran et al, 1994;Moran et al, 1995;Llobet-Brossa et al, 1998;Ravenschlag et al, 1999) as well as in the open ocean and estuarine regions (Elifantz et al, 2005;Fuchs et al, 2005;Kirchman et al, 2005;Morris et al, 2005). It is of particular interest to reveal the significance, composition and abundance of Gram positive bacterial communities in coastal tidally affected ecosystems and whether in this land-sea transition zone indigenous Gram positive bacteria do exist.…”

Sea‐floor fissures, biological communities and sediment fatty acids of the Northern Okushiri Ridge, Japan Sea: Implications for possible methane seepage

“…The FAME were then extracted into the mixture of hexane and methyl tert-butyl ether (1:1 by volume). The short-chain (C 9-20 ) FAME profiles were analyzed on a gas chromatograph (Hewlett-Packard 5890 Series II) equipped with a phenylmethyl silicone capillary (HP 19091B-102, Ultra 2), a flame ionization detector, and an automatic sampler (HP 7673 A 201) (Rajendran et al 1994).…”

“…Certain fatty acids are present in notable quantity or are unique for specific bacterial taxa. Such fatty acids often serve as biomarkers to characterize the microflora of environmental samples (Rajendran et al 1994). In this present study, the biomarker fatty acids for the key biogeochemical processes and micro-organisms were selected as follows Parkes 1987;Goodwin et al 1989;Findlay & Dobbs 1993;Jahnke et al 1995).…”

“…1;Miyashita et al confirmed by the occurrence of chemosynthetic micro-organisms in association with the fissures. For this purpose, the amounts and compositions of sediment fatty acids are known to characterize the sediment microflora effectively (Rajendran et al 1994;Naganuma et al 1996).…”