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Patrik Vestin

Patrik Vestin

Research engineer

Patrik Vestin

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

Author

  • Aleksander Wieckowski
  • Patrik Vestin
  • Jonas Ardö
  • Olivier Roupsard
  • Ousmane Ndiaye
  • Ousmane Diatta
  • Seydina Ba
  • Yélognissè Agbohessou
  • Rasmus Fensholt
  • Wim Verbruggen
  • Haftay Hailu Gebremedhn
  • Torbern Tagesson
Show all

Summary, in English

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.

Department/s

  • MERGE: ModElling the Regional and Global Earth system
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • Dept of Physical Geography and Ecosystem Science

Publishing year

2024-09-01

Language

English

Publication/Series

Global Change Biology

Volume

30

Issue

9

Document type

Journal article

Publisher

Wiley-Blackwell

Topic

  • Climate Science
  • Physical Geography

Keywords

  • carbon loss
  • climate change
  • eddy covariance
  • rainfall
  • Sahel
  • semiarid savanna
  • vapor pressure deficit
  • water availability

Status

Published

ISBN/ISSN/Other

  • ISSN: 1354-1013