The role of groundwater in CO2 production and carbon storage in Mediterranean peatlands: An isotope geochemistry approach

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State: Public
Version: Author's accepted manuscript
License: Not specified
Serval ID
serval:BIB_993E21D1B403
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The role of groundwater in CO2 production and carbon storage in Mediterranean peatlands: An isotope geochemistry approach
Journal
The Science of the total environment
Author(s)
Santoni S., Garel E., Gillon M., Babic M., Spangenberg J.E., Bomou B., Sebag D., Adatte T., van Geldern R., Pasqualini V., Mattei A., Huneau F.
ISSN
1879-1026 (Electronic)
ISSN-L
0048-9697
Publication state
Published
Issued date
25/03/2023
Peer-reviewed
Oui
Volume
866
Pages
161098
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Abstract
Peatlands are permanent wetlands recognized for ecosystem services such as biodiversity conservation and carbon storage capacity. Little information is available about their response to global change, the reason why most Earth system climate models consider a linear increase in the release of greenhouse gases (GHG), such as CO <sub>2</sub> , with increasing temperatures. Nevertheless, numerous studies suggest that an increase in the temperature may not imply a decrease in photosynthesis and carbon storage rates if water availability is sufficient, the latter being under the control of local hydrology mechanisms. Mediterranean peatlands well illustrate this fact. Since they are groundwater-dependent, they are hydrologically resilient to the strong seasonality of hydroclimatic conditions, especially during the summer drought. In the present study, we demonstrate that, even if such peatlands release CO <sub>2</sub> into the atmosphere, they can maintain a carbon storage capacity. To this end, a geochemical study disentangles the origin and fate of carbon within a Mediterranean peatland at the watershed scale. Field parameters, major ions, dissolved organic and inorganic carbon content and associated δ <sup>13</sup> C values allow for characterizing the seasonality of hydrochemical mechanisms and carbon input from an alluvial aquifer (where rain, river, shallow, and deep groundwater flows are mixing) to the peatland. The inorganic and organic content of peat soil and δ <sup>13</sup> C values of total organic matter and CO <sub>2</sub> complete the dataset, making it possible to provide arguments in favour of lower organic matter oxidation compared to primary production. Overall, this study highlights the groundwater role in the fluxes of CO <sub>2</sub> at the peatland-atmosphere interface, and more broadly the need to understand the interactions between the water and carbon cycles to build better models of the future evolution of the global climate.
Keywords
Groundwater-dependent ecosystem,, Origin of carbon, Peatland-atmosphere interface, Peatland‑carbon-water system, Sources and sinks of carbon
Pubmed
Web of science
Create date
06/03/2023 10:33
Last modification date
02/08/2023 7:13
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