https://oskar-bordeaux.fr/handle/20.500.12278/109283 2026-04-28T02:49:16Z https://oskar-bordeaux.fr/handle/20.500.12278/206474 COULON, Cécile; WHITE, Jeremy T.; PRYET, Alexandre; GATEL, Laura; LEMIEUX, Jean-Michel Abstract. In coastal zones, a major objective of groundwater management is often to determine sustainable pumping rates which avoid well salinization. Understanding how model and climate uncertainties affect optimal management solutions is essential for providing groundwater managers with information about salinization risk and is facilitated by the use of optimization under uncertainty (OUU) methods. However, guidelines are missing for the widespread implementation of OUU in real-world coastal aquifers and for the incorporation of climate uncertainty into OUU approaches. An ensemble-based OUU approach was developed considering parameter, observation and climate uncertainty and was implemented in a real-world island aquifer in the Magdalen Islands (Quebec, Canada). A sharp-interface seawater intrusion model was developed using MODFLOW-SWI2 and a prior parameter ensemble was generated containing multiple equally plausible realizations. Ensemble-based history matching was conducted using an iterative ensemble smoother which yielded a posterior parameter ensemble conveying both parameter and observation uncertainty. Sea level and recharge ensembles were generated for the year 2050 and were then used to generate a predictive parameter ensemble conveying parameter, observation and climate uncertainty. Multi-objective OUU was then conducted, aiming to both maximize pumping rates and minimize the probability of well salinization. As a result, the optimal trade-off between pumping and the probability of salinization was quantified considering parameter, historical observation and future climate uncertainty simultaneously. The multi-objective, ensemble-based OUU led to optimal pumping rates that were very different from a previous deterministic OUU and close to the current and projected water demand for risk-averse stances. Incorporating climate uncertainty into the OUU was also critical since it reduced the maximum allowable pumping rates for users with a risk-averse stance. The workflow used tools adapted to very high-dimensional, nonlinear models and optimization problems to facilitate its implementation in a wide range of real-world settings. 2024-01-18T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206473 GENET, Marion 2024-11-01T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206472 SHCHEPETKINA, Alina; MOAL, Paul; PEKAR, Stephen; WILLIAMS, Trevor We present a simple, quick, and high-resolution (approx.10 cm) method for calculating almost continuous calciumcarbonate (CaCO3) proxy records in deep-marine sediment cores based on the well-known dependence of NGR (natural gamma ray) on sediment clay content. The method used in this study is based on the assumption that sediment composition along the SAT (South Atlantic Transect) consists of two components: carbonate and clay. This assumption is reasonably accurate for the region under investigation. At carbonate-rich Site U1583 (66–97 wt% CaCO3), calculated CaCO3 wt% contents are within 4.18% at 1 standard deviation (r) of geochemical analyses of the CaCO3 wt% contents of discrete samples (measured using a coulometer), while at the more lithologically variable Site U1557 (0.1–92 wt% CaCO3), they are within 15.6% at 1r. Results indicate good to excellent correlations between the NGR- and coulometry-derived datasets, supporting the use of this method for carbonate stratigraphy, paleoceanography, and paleoclimate reconstructions. We provide an equation to derive CaCO3 wt% from NGR based on the SAT datasets. The procedure described below can be used to construct the higher resolution proxy CaCO3 records at other sites worldwide compared to discrete CaCO3 values. This method can assist with shipboard lithology determination and can guide core sampling. 2024-09-20T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206471 MICHALET, Richard; LOSAPIO, Gianalberto; KIKVIDZE, Zaal; BROOKER, Rob W.; BUTTERFIELD, Bradley J.; CALLAWAY, Ragan M.; CAVIERES, Lohengrin A.; LORTIE, Christopher J.; PUGNAIRE, Francisco I.; SCHÖB, Christian AbstractPlant interactions in extreme environments are often inferred from spatial associations and quantified by means of paired sampling. Yet, this method might be confounded by habitat‐sharing effects. Here, we address whether paired and random sampling methods provide similar results at varying levels of environmental heterogeneity. We quantified spatial associations with the two methods at three sites that encompass different micro‐environmental heterogeneity and stress levels: Mediterranean environments in Canary Islands, Spain, and Sardinia, Italy, and a cold alpine environment in Hokkaido, Japan. Then, we simulated plant communities with different levels of species micro‐habitat preferences, environmental heterogeneity, and stress levels. We found that differences in species associations between paired and random sampling were indistinguishable from zero in a homogeneous space. When simulating codispersion over a decreasing abundance gradient, both sampling methods correctly identified facilitation and distinguished it from codispersion. Yet, the pairwise method provided higher facilitation estimates than the random one. At each site, there were strong differences between beneficiary species in their spatial association with nurse species, and associations became more positive with increasing stress in Spain. Most importantly, there were no differences in results yielded by the two methods at any of the different stress levels at the Spanish and Japanese sites. At the Italian site, although micro‐environmental heterogeneity was low, we found weakly significant differences between methods that were unlikely due to habitat‐sharing effects. Thus, the paired sampling method can provide significant insights into net and long‐term effects of plant interactions in spatially conspicuous environments. 2023-07-05T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206455 CHKILI, Oumayma; BÉAT, Blanche Saint; KOUSRI, Kaouther Mejri; MEDDEB, Marouan; GAUVIN, Paula; DAVID, Valerie; SAFI, Georges; HLAILI, Asma Sakka; NIQUIL, Nathalie 2023-11-24T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206453 CHERIF, Wafa; KTARI, Leila; HMANI, Imen; ISMAIL, Amel; AHMED, Mehboob; GRIGNON DUBOIS, Micheline; BOUR, Monia El SPRINGER https://oskar-bordeaux.fr/handle/20.500.12278/206451 CABEZAS RABADAN, Carlos; PARDO-PASCUAL, J.E.; PALOMAR-VÁZQUEZ, J.; ROCH-TALENS, A.; GUILLÉN, J. 2024-03-01T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206449 BOURDON, Charlotte; CACHOT, Jérôme; GONZALEZ, Patrice; COUTURE, Patrice 2024-01-24T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206442 WUNDERLING, Nico; VON DER HEYDT, Anna; AKSENOV, Yevgeny; BARKER, Stephen; BASTIAANSEN, Robbin; BROVKIN, Victor; BRUNETTI, Maura; COUPLET, Victor; KLEINEN, Thomas; LEAR, Caroline; LOHMANN, Johannes; ROMAN-CUESTA, Rosa; SINET, Sacha; SWINGEDOUW, Didier; WINKELMANN, Ricarda; ANAND, Pallavi; BARICHIVICH, Jonathan; BATHIANY, Sebastian; BAUDENA, Mara; BRUUN, John; CHIESSI, Cristiano; COXALL, Helen; DOCQUIER, David; DONGES, Jonathan; FALKENA, Swinda; KLOSE, Ann; OBURA, David; ROCHA, Juan; RYNDERS, Stefanie; STEINERT, Norman; WILLEIT, Matteo 2024-01-26T00:00:00Z https://oskar-bordeaux.fr/handle/20.500.12278/206441 PETTON, Sébastien; PERNET, Fabrice; LE ROY, Valérian; HUBER, Matthias; MARTIN, Sophie; MACÉ, Éric; BOZEC, Yann; LOISEL, Stéphane; RIMMELIN-MAURY, Peggy; GROSSTEFFAN, Émilie; REPECAUD, Michel; QUEMENER, Loïc; RETHO, Michael; MANAC'H, Soazig; PAPIN, Mathias; PINEAU, Philippe; LACOUE-LABARTHE, Thomas; DEBORDE, Jonathan; COSTES, Louis; POLSENAERE, Pierre; RIGOUIN, Loïc; BENHAMOU, Jérémy; GOURIOU, Laure; LEQUEUX, Joséphine; LABOURDETTE, Nathalie; SAVOYE, Nicolas; MESSIAEN, Grégory; FOUCAULT, Elodie; OUISSE, Vincent; RICHARD, Marion; LAGARDE, Franck; VORON, Florian; KEMPF, Valentin; MAS, Sébastien; GIANNECCHINI, Léa; VIDUSSI, Francesca; MOSTAJIR, Behzad; LEREDDE, Yann; ALLIOUANE, Samir; GATTUSO, Jean-Pierre; GAZEAU, Frédéric 2024-04-04T00:00:00Z