Format

Send to

Choose Destination
FEMS Microbiol Ecol. 2007 Apr;60(1):40-50. Epub 2007 Jan 24.

Modulation of microbial predator-prey dynamics by phosphorus availability: growth patterns and survival strategies of bacterial phylogenetic clades.

Author information

1
Department of Limnology, Institute of Plant Biology, University of Zurich, Kilchberg, Switzerland.

Abstract

We simultaneously studied the impact of top-down (protistan grazing) and bottom-up (phosphorus availability) factors on the numbers and biomasses of bacteria from various phylogenetic lineages, and on their growth and activity parameters in the oligo-mesotrophic Piburger See, Austria. Enhanced grazing resulted in decreased proportions of bacteria with high nucleic acid content (high-NA bacteria) and lower detection rates by FISH. There was a change in the composition of the bacterial assemblage, whereby Betaproteobacteria were heavily grazed while Alphaproteobacteria and Cytophaga-Flavobacterium-Bacteroides were less affected by predators. Changes in bacterial assemblage composition were also apparent in the treatments enriched with phosphorus, and even more pronounced in the incubations in dialysis tubes (allowing relatively free nutrient exchange). Here, Betaproteobacteria became dominant and appeared to act as successful opportunistic competitors for nutrients. In contrast, Actinobacteria did not respond to surplus phosphorus by population growth, and, moreover, maintained their small size, which resulted in a very low biomass contribution. In addition, significant relationships between high-NA bacteria and several bacterial phylogenetic clades were found, indicating an enhanced activity status. By combining several single-cell methods, new insight is gained into the competitive abilities of freshwater bacteria from a variety of phylogenetic lineages under contrasting sets of bottom-up and top-down constraints.

[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for Wiley
Loading ...
Support Center