Piece 6 - The Critical Zone
How does the aquifer itself evolve?
The Critical Zone
Groundwater, weathering, vegetation and erosion
The basement aquifer is part of a much larger critical zone, extending from the vegetation canopy to the depth reached by groundwater circulation. In this system, groundwater is not only stored and transported: it also participates in chemical weathering and the export of dissolved elements.
Key findings
- Although smectites represent only about 4% of the soil volume, their dissolution accounts for approximately 75% of dissolved silica export, while primary silicate dissolution contributes about 15%.
- Vegetation strongly modifies water and solute fluxes. At Mule Hole, evapotranspiration limits runoff, while 80–90% of the annual solute flux exported by the stream passes through vegetation.
The groundwater system is part of a coupled rock–soil–water–vegetation system in which hydrology, weathering and biological processes interact.
OZCAR: The French Network of Critical Zone Observatories
J. Gaillardet, I. Braud, F. Hankard, S. Anquetin, O. Bour, N. Dorfliger, J.R. de Dreuzy, S. Galle, C. Galy, S. Gogo, L. Gourcy, F. Habets, F. Laggoun, L. Longuevergne, T. Le Borgne, F. Naaim-Bouvet, G. Nord, V. Simonneaux, D. Six, T. Tallec, C. Valentin, G. Abril, P. Allemand, A. Arènes, B. Arfib, L. Arnaud, N. Arnaud, P. Arnaud, S. Audry, V. Bailly Comte, C. Batiot, A. Battais, H. Bellot, E. Bernard, C. Bertrand, H. Bessière, S. Binet, J. Bodin, X. Bodin, L. Boithias, J. Bouchez, B. Boudevillain, I. Bouzou Moussa, F. Branger, J. J. Braun, P. Brunet, B. Caceres, D. Calmels, B. Cappelaere, H. Celle-Jeanton, F. Chabaux, K. Chalikakis, C. Champollion, Y. Copard, C. Cotel, P. Davy, P. Deline, G. Delrieu, J. Demarty, C. Dessert, M. Dumont, C. Emblanch, J. Ezzahar, M. Estèves, V. Favier, M. Faucheux, N. Filizola, P. Flammarion, P. Floury, O. Fovet, M. Fournier, A. J. Francez, L. Gandois, C. Gascuel, E. Gayer, C. Genthon, M. F. Gérard, D. Gilbert, I. Gouttevin, M. Grippa, G. Gruau, A. Jardani, L. Jeanneau, J. L. Join, H. Jourde, F. Karbou, D. Labat, Y. Lagadeuc, E. Lajeunesse, R. Lastennet, W. Lavado, E. Lawin, T. Lebel, C. Le Bouteiller, C. Legout, Y. Lejeune, E. Le Meur, N. Le Moigne, J. Lions, A. Lucas, J. P. Malet, C. Marais-Sicre, J. C. Maréchal, C. Marlin, P. Martin, J. Martins, J. M. Martinez, N. Massei, A. Mauclerc, N. Mazzilli, J. Molénat, P. Moreira-Turcq, E. Mougin, S. Morin, J. Ndam Ngoupayou, G. Panthou, C. Peugeot, G. Picard, M. C. Pierret, G. Porel, A. Probst, J. L. Probst, A. Rabatel, D. Raclot, L. Ravanel, F. Rejiba, P. René, O. Ribolzi, J. Riotte, A. Rivière, H. Robain, L. Ruiz, J. M. Sanchez-Perez, W. Santini, S. Sauvage, P. Schoeneich, J. L. Seidel, M. Sekhar, O. Sengtaheuanghoung, N. Silvera, M. Steinmann, A. Soruco, G. Tallec, E. Thibert, D. Valdes Lao, C. Vincent, D. Viville, P. Wagnon, R. Zitouna
Vadose Zone Journal, vol. 17, 2018, p. 180067
Jean-Jacques Braun, Jean-Christophe Maréchal, Jean Riotte, Jean-Loup Boeglin, Jean-Pierre {Bedimo Bedimo}, Jules Remy {Ndam Ngoupayou}, Brunot Nyeck, Henri Robain, M. Sekhar, Stéphane Audry, Jérôme Viers
Geochimica et Cosmochimica Acta, vol. 99, 2012, pp. 243-270
