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Ecological niche separation in the Polynucleobacter subclusters linked to quality of dissolved organic matter: a demonstration using a high sensitivity cultivation‐based approach
Author(s) -
Watanabe Keiji,
Komatsu Nobuyuki,
Kitamura Tatsumi,
Ishii Yuichi,
Park HoDong,
Miyata Ryo,
Noda Naohiro,
Sekiguchi Yuji,
Satou Takayuki,
Watanabe Mirai,
Yamamura Shigeki,
Imai Akio,
Hayashi Seiji
Publication year - 2012
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2012.02815.x
Subject(s) - bacterioplankton , biology , dissolved organic carbon , organic matter , relative species abundance , niche , bacteria , abundance (ecology) , ecology , microbial ecology , botany , environmental chemistry , nutrient , phytoplankton , chemistry , genetics
Summary The free‐living, cosmopolitan, freshwater betaproteobacterial bacterioplankton genus Polynucleobacter was detected in different years in 11 lakes of varying types and a river using the size‐exclusion assay method (SEAM). Of the 350 strains isolated, 228 (65.1%) were affiliated with the Polynucleobacter subclusters PnecC (30.0%) and PnecD (35.1%). Significant positive correlations between fluorescence in situ hybridization and SEAM data were observed in the relative abundance of PnecC and PnecD bacteria to Polynucleobacter communities (PnecC + PnecD). Isolates were mainly PnecC bacteria in the samples with a high specific UV absorbance at 254 nm (SUVA 254 ), and a low total hydrolysable neutral carbohydrate and amino acid (THneutralCH + THAA) content of the dissolved organic matter (DOM) fraction, which is known to be correlated with a high humic content. In contrast, the PnecD bacteria were abundant in samples with high chlorophyll a and/or THneutralCH + THAA concentrations, indicative of primary productivity. With few exceptions, differences in the relative abundance of PnecC and PnecD in each sample, determined using a high‐sensitivity cultivation‐based approach, were due to DOM quality. These results suggest that the major DOM component in the field, which is allochthonously or autochthonously derived, is a key factor for ecological niche separation between PnecC and PnecD subclusters.