What Does the Triple Isotopic Composition of Oxygen in Precipitation, Groundwater, Soil Water, Plant Water, and Phytoliths Reveal About Current and Past Hydrological Cycles?
Year: 2025
Type: article
Abstract: Quantitative data are needed to constrain the feedback loops between vegetation and hydroclimate. In this study, the amplitudes of variations in the triple oxygen isotope composition of water at the soil‐plant‐atmosphere interface are measured in savanna and dry forest contexts in West Africa (Benin and Senegal). Comparison of in situ data and model estimates reveals the following: (a) The value of 17 O‐excess for reconstructing climate archives is confirmed, given its small variability in precipitation (a few per meg) compared to the very large magnitude of change in the 17 O‐excess of phytoliths (hundreds of per meg) in response to RH changes. (b) At the beginning of the dry season, the 17 O‐excess in soil water is lower than that of precipitation by only 30 per meg in the sandy‐loam soils and 50 per meg in the sandy soil. This shows the limited contribution of evaporated water to bulk soil water and provides clues to constrain the complex hydrological functioning of soils; (c) The regression line connecting the triple oxygen isotope composition of water in the stems and leaves of grasses and trees can be used to determine the origin of the water absorbed by the roots. Semi‐evergreen trees draw their water from the water table during the dry season, whereas grasses and semi‐evergreen trees use surface water during the wet season. These original data open up new perspectives for the use of the triple oxygen isotope composition of water and phytoliths to better understand current and past hydrological cycles.
DOI: 10.1029/2024jg008615
Authors: Anne Alexandre, Clement Outrequin, Christine Vallet‐Coulomb, Christophe Peugeot, Manuela Grippa, Julie Aleman, Claudia Voigt, Amaelle Landais, Eric Mougin, Ousmane Ndiaye, Corinne Sonzogni, David Au Yang, Jean‐Charles Mazur, Martine Couapel, Jérôme Ogée, Theodore Ouani, Simon Afouda, Maxime Wubda, Nogmana Soumaguel, Alfred Houngnon, Torbern Tagesson, Rasmus Fensholt
Institutions: Centre National de la Recherche Scientifique, Aix-Marseille Université, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Centre de Recherche et d’Enseignement de Géosciences de l’Environnement, Institut de Recherche pour le Développement, Laboratoire HydroSciences Montpellier, Géosciences Environnement Toulouse, Université de Toulouse, Technische Universität Dresden, Université de Versailles Saint-Quentin-en-Yvelines, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Laboratoire des Sciences du Climat et de l'Environnement, Institut Sénégalais de Recherches Agricoles, Interaction Sol Plante Atmosphère, Institut de Recherche pour le Développement, Lund University, University of Copenhagen
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,070
Awards: G122150903, Improving African sub-seasonal vegetation feedback in Earth system models using multiple satellite observations and field measurements, G3497940434, Lesbian Moms and Their Kids At Court, G3936060667, Past dynamic of continental atmospheric humidity and vegetation: new insights from the triple isotopic composition of oxygen, Quantitative reconstruction of past hydroclimates : the triple oxygen isotope composition (17O-excess) of biogenic silica perspective, Decreasing uncertainties in the regional contributions to the global carbon cycle with state-of-the-art Earth observation products, Impact of land use on land-atmosphere exchange of greenhouse gases in savannahs of Sahel, G6267888834, G6584163665, G6803667113
OpenAlex ID: W7091473218