Microbial contribution to continental wetland carbon budget

Project Information

MICADO

Grant agreement ID: 896189

DOI

10.3030/896189

Project terminated on 28 September 2022

EC signature date 24 April 2020

Start date 4 January 2021

End date 3 January 2023

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 196 707,84

EU contribution

€ 196 707,84

Coordinated by

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France

Periodic Reporting for period 1 - MICADO (Microbial contribution to continental wetland carbon budget)

Reporting period: 2021-01-04 to 2023-01-03

Summary of the context and overall objectives of the project

Continental wetlands are major carbon dioxide sinks but the second largest source of methane. Monitoring of wetland methane emissions revealed large inter-site variability that is hard to explain in the framework of current biogeochemical theories. Methane production in wetlands is an anaerobic microbial driven process involving a complex set of microbial metabolisms depending on the availability of (i) energy (via the presence of specific redox couples), (ii) organic substrates and (iii) specific microbial communities. To understand the complexity of microbial drivers on wetland methane emissions and quantify their contribution, the MICADO project will set up a multidisciplinary approach linking isotope organic geochemistry and environmental microbiology to assess microbial functioning in situ. As an organic geochemist I have developed an innovative approach to trace in situ microbial activity via compound specific carbon isotope analysis of microbe macromolecules and organic metabolites. The host institution is a leader in France in environmental microbiology and biogeochemistry developing high-throughput metagenomics and microbial rate assessments, for which I will be trained during the MICADO project. These techniques are highly complementary and combined they will provide a comprehensive knowledge on microbial metabolisms involved in organic matter degradation encompassing their complexity and interactions. This will revisit the relationships between organic substrate availability and microbial communities and will contribute at estimating the impact of microbial activity on wetland methane emissions. This project will give me the opportunity to acquire fundamental knowledge and to develop original lines of research that will consolidate my position as an independent scientist in biogeochemistry.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

A field campaign was organized in June 2021 to collect soil, porewater and atmospheric samples. From these samples, genomic and lipidomic data were extracted and the concentration of reactive dissolved gases as well as major nutrients and inorganic constituents was determined. This enabled to identify the major microbial taxa present in the wetland as well as the major microbial processes. In particular, an increase of archaeal taxa, dominated by Ca. Bathyarchaeota, was observed with depth. Combined analysis of metagenomic data and compound specific isotopic composition of microbial membrane lipids evidenced, for the first time in continental settings, the autotrophic metabolism of Ca. Bathyarchaeaota. In the second year of the project, soil samples were incubated in flow-through reactors with either carbon dioxide (CO2) or methane (CH4) as the major carbon source. Genomic and lipidomic data are under interpretation but preliminary data of the analysis of CO2, CH4 and major inorganic compounds revealed substantial anaerobic oxidation of CH4, potentially related to sulfate reduction.

Related internship supervised :
-Pierre Lebreton, undergraduate internship, 12/04/2021 - 18/06/2021, dissolved gases measurements in flow-through reactors by membrane inlet mass spectrometry (MIMS).
-Karine Lemaître, graduate internship, 28/02/2022 – 27/08/2022, methane dynamics in continental wetlands

Communications in international conferences :
-Coffinet S., Dufresne A., Quaiser A., Longuevergne L., Hinrichs K.-U. Laverman A.M. Identification of microbial methane sources and sinks in an aquifer-fed continental wetland with a multi-omics approach. Goldschmidt, virtual conference, July 2021.
-Coffinet S., Dufresne A., Quaiser A., Hinrichs K.-U. Laverman A. M., Identification of microbial methane sources and sinks in an aquifer-fed continental wetland with a multi-omics approach, EGU General Assembly, Vienne, Austria, April 2022.

Communications in national events :
-Coffinet S., Dufresne A., Quaiser A., Longuevergne L., Hinrichs K.-U. Laverman A. M., Identification of microbial methane sources and sinks in an aquifer-fed continental wetland with a multi-omics approach, 10th symposium of the French association in microbial ecology (AFEM), virtual edition, November 2021.
-Coffinet S., Dufresne A., Quaiser A., Longuevergne L., Hinrichs K.-U. Laverman A.M. Identification of microbial methane sources and sinks in an aquifer-fed continental wetland with a multi-omics approach. OZCAR Summer School, Barcelonnette, France, July 2021.
-Lemaître K., Coffinet S., Chatton E., Dufresne A., Quaiser A., Labasque T., Laverman A. Methane dynamics in continental wetlands, 5th meeting of the French Researchers in Organic Geochemistry (FROG), Rennes, France, July 2022.

Invited seminars:
-Hinrichs’ lab, MARUM, Bremen University, Germany (March 2022).

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

During this project, the importance of a recently discovered archaeal phylum, Ca. Bathyarchaeota, in the carbon cycle of continental wetlands was revealed. For the first time, we were able to show that this phylum has an autotrophic behavior assimilating dissolved CO2 supplied by the underlying aquifer. We expect, based on the data collected during the flow-through incubation set up in the second year of the project, to identify the major microbial taxa related to the production and consumption of CH4 which will be of utmost importance to predict the behavior of the studied wetland under future climate conditions.

This project also generated several opprtunities to raise the general public's awareness of the importance of microbial processes for maintaining ecosystems functions, notably via the participation of the ECR to the events listed below:
-Village des sciences, Champs Libres, Rennes, France (October 2021).
-Participation to the radio show (In)attendue of the C-Lab radio (https://www.c-lab.fr/emission/inattendue/inattendue-village-des-sciences-2021.html).
-Village des sciences, Champs Libres, Rennes, France (October 2022).

Overview of carbon processes in continental wetlands