Predation as a shaping force for the phenotypic and genotypic composition of planktonic bacteria |
| |
Authors: | Jürgens Klaus Matz Carsten |
| |
Institution: | Max Planck Institute for Limnology, Pl?n, Germany. juergens@mpil-ploen.mpg.de |
| |
Abstract: | Predation is a major mortality factor of planktonic bacteria and an important shaping force for the phenotypic and taxonomic
structure of bacterial communities. In this paper we: (1) summarise current knowledge on bacterial phenotypic properties which
affect their vulnerability towards grazers, and (2) review experimental evidence demonstrating that this phenotypic heterogeneity
results in shifts of bacterial community composition during enhanced protist grazing pressure. Size-structured interactions
are especially important in planktonic systems and bacterial cell size influences the mortality rate and the type of grazer
to which bacteria are most susceptible. When protists are the major bacterivores, both very small and large bacterial cells
gain some size refuge. Recent studies have revealed that also various non-morphological traits such as motility, physicochemical
surface characters and toxicity affect bacterial vulnerability and protist feeding success. These properties are effective
at different stages during the feeding process of interception feeding flagellates (encounter, capture, ingestion, digestion).
Grazing-resistant bacteria in natural communities can account for a substantial portion of the total bacterial biomass at
least in more productive aquatic systems. In field and laboratory experiments it has been demonstrated that increased protozoan
grazing results in shifts in the phenotypic and genotypic composition of the bacterial assemblage. The importance of this
shaping force for the bacterial community structure depends, however, on the overall food web structure, especially on the
composition of the metazooplankton. Whereas the structuring impact of bacterial grazers is well documented, relatively little
is known about how grazing-mediated changes in bacterial communities influence microbially mediated processes and biogeochemically
important transformations.
This revised version was published online in August 2006 with corrections to the Cover Date. |
| |
Keywords: | bacterial community structure bacterioplankton phenotypic properties predation predator– prey interactions protozoa |
本文献已被 PubMed SpringerLink 等数据库收录! |
|