Disentangling microbial exopolymer dynamics in intertidal sediments
Identification of microbial exopolymer producers in sandy and muddy intertidal sediments by compound-specific isotope analysis
Recommendation: posted 10 October 2023, validated 11 October 2023
Risse-Buhl, U. and Rädecker, N. (2023) Disentangling microbial exopolymer dynamics in intertidal sediments. Peer Community in Ecology, 100519. 10.24072/pci.ecology.100519
The secretion of extracellular polymeric substances (EPS) enables microorganisms to shape and interact with their environment . EPS support cell adhesion and motility, offer protection from unfavorable conditions, and facilitate nutrient acquisition and transfer between microorganisms . EPS production and consumption thus control the formation and structural organization of biofilms . However, in marine environments, our understanding of the sources and composition of EPS is limited.
In this study, Hubas et al.  compare the carbon and nitrogen isotope ratios in EPS with the carbon isotope ratios of fatty acid biomarkers to identify the main EPS producers in intertidal sediments. The authors find pronounced differences in the diversity, composition, isotope signatures, and production/consumption dynamics of EPS between muddy and sandy environments. While the contribution of diatoms was highest in the bound fraction of EPS in muddy environments, diatom contribution was highest in the colloidal fraction of EPS in sandy environments. These differences between sites likely reflect the functional differences in EPS dynamics of epipelic and episammic sediment communities.
Taken together, the innovative approach of the authors provides insights into the diversity and origin of EPS in microphytobenthic communities and highlights the importance of different microbial groups in EPS production. These findings are vital for understanding EPS dynamics in microbial interactions and their role in the functioning of coastal ecosystems.
- Flemming, H.-C. (2016) EPS-then and now. Microorganisms 4, 41 https://doi.org/10.3390/microorganisms4040041
- Wolfaardt, G.M. et al. (1999) Function of EPS. In Microbial Extracellular Polymeric Substances, pp. 171–200, Springer Berlin Heidelberg https://doi.org/10.1007/978-3-642-60147-7
- Flemming, H.-C. et al. (2007) The EPS matrix: the “house of biofilm cells.” J. Bacteriol. 189, 7945–7947 https://doi.org/10.1128/jb.00858-07
- Hubas, C. et al. (2022) Identification of microbial exopolymer producers in sandy and muddy intertidal sediments by compound-specific isotope analysis. bioRxiv, ver. 2 peer-reviewed and recommended by Peer Community in Ecology. https://doi.org/10.1101/2022.12.02.516908
The recommender in charge of the evaluation of the article and the reviewers declared that they have no conflict of interest (as defined in the code of conduct of PCI) with the authors or with the content of the article. The authors declared that they comply with the PCI rule of having no financial conflicts of interest in relation to the content of the article.
This study was supported by the BIO-Tide project (The role of microbial biodiversity in the functioning of marine tidal flat sediments), funded through the 2015–2016 BiodivERsA COFUND call for research proposals, with the national funders BelSPO (BRAIN-be contract BR/175/A1/BIO-Tide-BE), FWO (3G0H6816), ANR (ANR-16-EBI3-0008), and SNSF. We additionally acknowledge funding from FWO project G003820N. The post-doctoral grant of J. G-B was supported by the Regional Council of Brittany, SAD program and META-Tide projects.
Evaluation round #1
DOI or URL of the preprint: https://doi.org/10.1101/2022.12.02.516908
Version of the preprint: 1
Author's Reply, 14 Jul 2023
Decision by Ute Risse-Buhl, posted 27 Mar 2023, validated 27 Mar 2023
Dear Dr. Hubas and co-authors,
both reviewers and I very much enjoyed reading your preprint. You illustrate a very interesting and novel approach. The reviewers highlighted that your preprint contains much needed information on EPS and is of high impact. You will see that both reviewers raised a number of suggestions on how to improve the manuscript. I highly recommend revising the pre-print and considering the comments of both reviewers.