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Experimental manipulations of microbial food web interactions in a humic lake: shifting biological drivers of bacterial community structure
Author(s) -
Kent Angela D.,
Jones Stuart E.,
Lauster George H.,
Graham James M.,
Newton Ryan J.,
McMahon Katherine D.
Publication year - 2006
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.1462-2920.2006.01039.x
Subject(s) - bacterioplankton , microbial food web , biology , food web , phytoplankton , ribosomal intergenic spacer analysis , trophic level , ecology , ecological succession , community structure , abundance (ecology) , microbial ecology , microbial population biology , unifrac , phylogenetic tree , nutrient , 16s ribosomal rna , ribosomal dna , bacteria , biochemistry , genetics , gene
Summary A previous multiyear study observed correlations between bacterioplankton community composition (BCC) and abundance and the dynamics of phytoplankton populations and bacterivorous grazers in a humic lake. These observations generated hypotheses about the importance of trophic interactions (both top‐down and bottom‐up) for structuring bacterial communities in this lake, which were tested using two multifactorial food web manipulation experiments that separately manipulated the intensity of grazing and the composition of the phytoplankton community. Our results, combined with field observations, suggest that a hierarchy of drivers structures bacterial communities in this lake. While other studies have noted links between aggregate measures of phytoplankton and bacterioplankton communities, we demonstrate here correlations between succession of phytoplankton assemblages and BCC as assessed by automated ribosomal intergenic spacer analysis (ARISA). We used a novel approach linking community ARISA data to phylogenetic assignments from sequence analysis of 16S rRNA gene clone libraries to examine the responses of specific bacterial phylotypes to the experimental manipulations. The synchronous dynamics of these populations suggests that primary producers may mediate BCC and diversity through labile organic matter production, which evolves in quality and quantity during phytoplankton succession. Superimposed on this resource‐mediated control of BCC are brief periods of intense bacterivory that impact bacterial abundance and composition.