Organic matter processing by microbial communities throughout the Atlantic water column as revealed by metaproteomics
Bergauer, K.; Fernàndez-Guerra, A.; Garcia, J.A.L.; Sprenger, R.R.; Stepanauskas, R.; Pachiadaki, M.G.; Jensen, O.N.; Herndl, G. (2018). Organic matter processing by microbial communities throughout the Atlantic water column as revealed by metaproteomics. Proc. Natl. Acad. Sci. U.S.A. 115(3): E400-E408. https://dx.doi.org/10.1073/pnas.1708779115Additional data: In: Proceedings of the National Academy of Sciences of the United States of America. The Academy: Washington, D.C.. ISSN 0027-8424; e-ISSN 1091-6490, more |   |
| Author keywords | transporter proteins; organic matter; deep sea; Atlantic Ocean; metaproteomics |
| Authors | | Top | - Bergauer, K.
- Fernàndez-Guerra, A.
- Garcia, J.A.L.
- Sprenger, R.R.
| - Stepanauskas, R.
- Pachiadaki, M.G.
- Jensen, O.N.
- Herndl, G., more
| |
| Abstract | The phylogenetic composition of the heterotrophic microbialcommunity is depth stratified in the oceanic water column downto abyssopelagic layers. In the layers below the euphotic zone, it hasbeen suggested that heterotrophic microbes rely largely on solubilizedparticulate organic matter as a carbon and energy sourcerather than on dissolved organic matter. To decipher whetherchanges in the phylogenetic composition with depth are reflectedin changes in the bacterial and archaeal transporter proteins, wegenerated an extensive metaproteomic and metagenomic datasetof microbial communities collected from 100- to 5,000-m depth inthe Atlantic Ocean. By identifying which compounds of the organicmatter pool are absorbed, transported, and incorporated intomicrobial cells, intriguing insights into organic matter transformationin the deep ocean emerged. On average, solute transportersaccounted for 23% of identified protein sequences in the lowereuphotic and ∼39% in the bathypelagic layer, indicating the centralrole of heterotrophy in the dark ocean. In the bathypelagic layer,substrate affinities of expressed transporters suggest that, in additionto amino acids, peptides and carbohydrates, carboxylic acidsand compatible solutesmay be essential substrates for themicrobialcommunity. Key players with highest expression of solute transporterswere Alphaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria,accounting for 40%, 11%, and 10%, respectively,of relative protein abundances. The in situ expression of solutetransporters indicates that the heterotrophic prokaryotic communityis geared toward the utilization of similar organic compoundsthroughout the water column, with yet higher abundances of transporterstargeting aromatic compounds in the bathypelagic realm. |
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