AME 71:15-24 (2013)  -  DOI: https://doi.org/10.3354/ame01660

Reduced diversity and changed bacterioplankton community composition do not affect utilization of dissolved organic matter in the Adriatic Sea

Johanna Sjöstedt1, Mikael Pontarp2, Tinkara Tinta3, Hanna Alfredsson1,5, Valentina Turk3, Per Lundberg2, Åke Hagström1, Lasse Riemann1,4,*

1Department of Natural Sciences, Linnaeus University, 391 82 Kalmar, Sweden
2Theoretical Population Ecology and Evolution Group, Department of Biology, Lund University, 223 62 Lund, Sweden
3Marine Biology Station, National Institute of Biology, 6630 Piran, Slovenia
4Marine Biological Section, University of Copenhagen, 3000 Helsingør, Denmark
5Present address: Department of Geology, Lund University, 223 62 Lund, Sweden
*Corresponding author. Email:

ABSTRACT: To obtain insights into the coupling between community composition, diversity and community function, bacterioplankton assemblages from the Gulf of Trieste (Northern Adriatic Sea) were exposed to increasing environmental stress throughout 2 wk in continuous seawater cultures to construct communities differing in composition and diversity. The assemblages were exposed to (1) decreased temperature, (2) decreased temperature and phosphate addition or (3) decreased temperature, phosphate addition and lowered oxygen level. Bacterial and viral abundances as well as bacterial community composition stabilized during the second week of the experiment. Denaturing gradient gel electrophoresis and pyrosequencing of 16S rRNA genes showed dramatic reductions in bacterial diversity in all treatments and major compositional differences relative to the inoculum. Nevertheless, no differences in the ability to exploit dissolved organic carbon (DOC) were found for the acquired communities relative to the inoculum, indicating that the bacterial communities were functionally redundant. We speculate that oscillations in exploitation of the DOC pool in situ are mainly governed by factors limiting the overall bacterial growth, rather than perturbations affecting only subsets of the microbial biota.


KEY WORDS: Diversity · Functional redundancy · Community structure · Continuous cultures · DOC


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Cite this article as: Sjöstedt J, Pontarp M, Tinta T, Alfredsson H and others (2013) Reduced diversity and changed bacterioplankton community composition do not affect utilization of dissolved organic matter in the Adriatic Sea. Aquat Microb Ecol 71:15-24. https://doi.org/10.3354/ame01660

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