# Carbon balance modification in Sphagnum-dominated peat mesocosms invaded by Molinia caerulea

Fabien Leroy, Sébastien Gogo, Christophe Guimbaud, Léonard

Bernard-Jannin, Fatima Laggoun-Défarge

► To cite this version:

Fabien Leroy, Sébastien Gogo, Christophe Guimbaud, Léonard Bernard-Jannin, Fatima Laggoun-Défarge. Carbon balance modification in Sphagnum-dominated peat mesocosms invaded by Molinia caerulea. EGU General Assembly 2017, Apr 2017, Vienne, Austria. insu-01664678

HAL Id: insu-01664678

https://insu.hal.science/insu-01664678

Submitted on 13 Feb 2022

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>

Distributed under a Creative Commons Attribution 4.0 International License
<figure><img src="image_2.png" /></figure>

# Carbon balance modification in Sphagnum-dominated peat mesocosms invaded by Molinia caerulea

Fabien Leroy (1,2,3), Sébastien Gogo (1,2,3), Christophe Guimbaud (4,5), Léonard Bernard-Jannin (1,2,3), Fatima Laggoun-Défarge (1,2,3)

(1) Université d'Orléans, ISTO, UMR 7327, 45071, Orléans, France, (2) CNRS, ISTO, UMR 7327, 45071 Orléans, France,

(3) BRGM, ISTO, UMR 7327, BP 36009, 45060 Orléans, France, (4) Université d'Orléans, LPC2E, UMR 7328, 45071, Orléans, France, (5) CNRS, LPC2E, UMR 7328, 45071, Orléans, France

Plant communities have a key role in regulating greenhouse gas (GHG) emissions in peatland ecosystems and thus on their capacity to act as carbon (C) sink. However, in response to global change, boreal and temperate peatlands may shift from Sphagnum to vascular plant-dominated peatlands that may alter their C-sink function. We set up a mesocosm experiment to investigate how the main GHG fluxes (CO₂ and CH₄) are affected by plant community modification from Sphagnum mosses to Molinia caerulea dominance. Gross primary production (GPP), ecosystem respiration (ER) and CH₄ emissions models were used to compare the C balance and global warming potential under both vegetation cover. While the annual CO₂ and CH₄ emissions modeling estimated an output of respectively 652 and 18 gC m⁻² y⁻¹ in Sphagnum mesocosms, it represented a release of 1473 and 50 gC m⁻² y⁻¹ with Molinia caerulea occurrence. Annual modeled GPP was respectively -495 and -1968 gC m⁻² y⁻¹ in Sphagnum and Molinia mesocosms leading to a net ecosystem carbon balance (NECB) of 175 g C m⁻² y⁻¹ in Sphagnum mesocosms (i.e. a C-source) and of -445 gC m⁻² y⁻¹ for Molinia ones (i.e. a C-sink). Even if CH₄ emission accounted for a small part of the gaseous C efflux (~ 3%), its global warming potential value to get CO₂ equivalent makes both plant communities acting as a warming climate effect. The vegetation shift from Sphagnum mosses to Molinia caerulea seems beneficial for C sequestration regarding the gaseous pool. However, roots and litters of Molinia caerulea could further provide substrates for C emissions and dissolved organic C release.