AME 76:27-37 (2015)  -  DOI: https://doi.org/10.3354/ame01765

Interspecific interactions drive chitin and cellulose degradation by aquatic microorganisms

Gianluca Corno1,*, Ivette Salka2, Kirsten Pohlmann2, Alex R. Hall3, Hans-Peter Grossart2,4 

1CNR-Institute of Ecosystem Study, Largo Tonolli 50, 28922 Verbania, Italy
2Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2, 16775 Stechlin, Germany
3Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
4Institute of Biochemistry and Biology, Potsdam University, Am neuen Palais 10, 14469 Potsdam, Germany
*Corresponding author:

ABSTRACT: Complex biopolymers (BPs) such as chitin and cellulose provide the majority of organic carbon in aquatic ecosystems, but the mechanisms by which communities of bacteria in natural systems exploit them are unclear. Previous degradation experiments in artificial systems predominantly used microcosms containing a single bacterial species, neglecting effects of interspecific interactions. By constructing simplified aquatic microbial communities, we tested how the addition of other bacterial species, of a nanoflagellate protist capable of consuming bacteria, or of both, affect utilization of BPs. Surprisingly, total abundance of resident bacteria in mixed communities increased upon addition of the protist. Concomitantly, bacteria shifted from free-living to aggregated morphotypes that seemed to promote utilization of BPs. In our model system, these interactions significantly increased productivity in terms of overall bacterial numbers and carbon transfer efficiency. This indicates that interactions on microbial aggregates may be crucial for chitin and cellulose degradation. We therefore suggest that interspecific microbial interactions must be considered when attempting to model the turnover of the vast pool of complex biopolymers in aquatic ecosystems.


KEY WORDS: Aggregation · Flagellate grazing · Ecological interactions · Microbial carbon transfer · Polymer degradation · System ecology


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Cite this article as: Corno G, Salka I, Pohlmann K, Hall AR, Grossart HP (2015) Interspecific interactions drive chitin and cellulose degradation by aquatic microorganisms. Aquat Microb Ecol 76:27-37. https://doi.org/10.3354/ame01765

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