Eddy covariance measurements reveal a decreased carbon sequestration strength 2010-2022 in an African semiarid savanna

Wieckowski Aleksander, Vestin Patrik, Ardö Jonas, Roupsard Olivier, Ndiaye Ousmane, Diatta Ousmane, Ba Seydina, Agbohessou Yélognissè frédi, Fensholt Rasmus, Verbruggen Wim, Gebremedhn Haftay Hailu, Tagesson Torbern. 2024. Eddy covariance measurements reveal a decreased carbon sequestration strength 2010-2022 in an African semiarid savanna. Global Change Biology, 30 (9):e17509, 18 p.

https://doi.org/10.1111/gcb.17509

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

Prévisualisation

Version publiée - Anglais
Sous licence

.
Global Change Biology - 2024 - Wieckowski - Eddy covariance measurements reveal a decreased carbon sequestration strength.pdf
Télécharger (20MB) | Prévisualisation

Url - jeu de données - Entrepôt autre : https://doi.org/10.5061/dryad.3ffbg79t0

Résumé : Monitoring the changes of ecosystem functioning is pivotal for understanding the global carbon cycle. Despite its size and contribution to the global carbon cycle, Africa is largely understudied in regard to ongoing changes of its ecosystem functioning and their responses to climate change. One of the reasons is the lack of long-term in situ data. Here, we use eddy covariance to quantify the net ecosystem exchange (NEE) and its components—gross primary production (GPP) and ecosystem respiration (Reco) for years 2010–2022 for a Sahelian semiarid savanna to study trends in the fluxes. Significant negative trends were found for NEE (12.7 ± 2.8 g C m2 year−1), GPP (39.6 ± 7.9 g C m2 year−1), and Reco (32.2 ± 8.9 g C m2 year−1). We found that NEE decreased by 60% over the study period, and this decrease was mainly caused by stronger negative trends in rainy season GPP than in Reco. Additionally, we observed strong increasing trends in vapor pressure deficit, but no trends in rainfall or soil water content. Thus, a proposed explanation for the decrease in carbon sink strength is increasing atmospheric dryness. The warming climate in the Sahel, coupled with increasing evaporative demand, may thus lead to decreased GPP levels across this biome, and lowering its CO2 sequestration.

Mots-clés Agrovoc : séquestration du carbone, cycle du carbone, écosystème, zone semi-aride, changement climatique, carbone, variation saisonnière, atténuation des effets du changement climatique, dioxyde de carbone, conditions météorologiques

Mots-clés géographiques Agrovoc : Sahel, Sénégal

Mots-clés libres : Carbon loss, Climate Change, Eddy covariance, Rainfall, Sahel, Semiarid savanna, Vapor pressure deficit, Water availability

Agences de financement européennes : European Commission

Agences de financement hors UE : Danmarks Frie Forskningsfond, Svenska Research Council Formas, Swedish National Space Agency, Lunds Universitet

Auteurs et affiliations