Home Page | Help | Contact | Log In | Search | Follow us: Official ASLO 2012 ASM Twitter Feed Official ASLO 2012 ASM Facebook Page

Watanabe, K., National Institute for Environmental Studies, Tsukuba, Japan, watanabe.keiji@nies.go.jp
Imai, A., National Institute for Environmental Studies, Tsukuba, Japan, aimai@nies.go.jp
Watanabe, M., National Institute for Environmental Studies, Tsukuba, Japan, watanabe.mirai@nies.go.jp
Yamamura, S., National Institute for Environmental Studies, Tsukuba, Japan, yshige@nies.go.jp
Hayashi, S., National Institute for Environmental Studies, Tsukuba, Japan, shayashi@nies.go.jp

ECOLOGICAL NICHE SEPARATION IN THE POLYNUCLEOBACTER SUBCLUSTERS LINKED TO QUALITY OF DISSOLVED ORGANIC MATTER

Effective detection of the free-living, cosmopolitan, freshwater betaproteobacterial bacterioplankton genus Polynucleobacter from 11 lakes of varying lake types (oligotrophic, eutrophic, and dystrophic), and a river, were carried out using the size-exclusion assay method with a size-specific filtration step at two times per site in separate years. Of the 350 strains that were isolated only once and by a single plating per sample, 228 strains were shown to be affiliated with Polynucleobacter subclusters PnecC and PnecD. The isolates were mainly PnecC bacteria when the samples had a high specific UV absorbance at 254 nm, and low total hydrolyzable neutral carbohydrates and amino acids (THneutralCH+THAA) content of the dissolved organic matter (DOM) fraction, which are known to be correlated with the content of humic substances. On the other hand, the PnecD bacteria showed high representation in the samples with high chlorophyll a and/or THneutralCH+THAA concentrations, indicative of high primary productivity. These results suggest that the major DOM component in the freshwater environment, which is allochthonously or autochthonously derived, is one of key factors in ecological niche separation between PnecC and PnecD subclusters.

Poster presentation

Session #:SS17
Date: 7/10/2012
Time: 18:00 - 20:00