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Energy expenditure of Adélie penguins during the breeding season: females pay the cost in years of low food availability
No full textInternational audienceChanges in prey availability can lead to mismatches between consumers and resources, decreasing the fitness of consumers, especially during periods of high energy demand such as reproduction. We investigated interseasonal variation in the foraging behaviour of chick-rearing Adélie penguins, Pygoscelis adeliae, in a declining colony in the West Antarctic Peninsula to assess the impact of changes in prey abundance. Specifically, we analysed how these changes affect the energetic cost of males and females during the breeding season. Using information from foraging trips, diet, body condition and daily energy expenditure of 38 Adélie penguins breeding in Ardley Island, King George Island, in 2019/2020 and 2021/2022, we found that during low food availability conditions, penguins were forced to increase their foraging effort and their body mass was lower. Specifically, females extended their foraging trips, resulting in 40% higher energy expenditure compared to a year with high prey availability. We observed no significant changes in physiological condition, breeding success or trophic niche. The lower fat reserves and higher energy expenditure of females during the breeding season with low food availability may render them more vulnerable to the challenging conditions of the winter season, with potential negative consequences on population trends
A new global high-resolution wave model for the tropical ocean using WAVEWATCH III version 7.14
No full textInternational audienceClimate change is driving sea-level rise and potentially intensifying extreme events in the tropical belt, thereby increasing coastal hazards. On tropical islands, extreme sea levels and subsequent marine flooding can be triggered by cyclones but also distant-source swells. Knowledge of sea states in the tropical ocean is thus of key importance, and their study is usually based on spectral wave models. However, existing global wave models typically employ regular grids with a coarse resolution, which fail to accurately represent volcanic archipelagos, a problem usually circumvented by the use of obstruction grids but typically resulting in large negative biases. To overcome this problem, this study presents a new global wave model with a focus on distant-source swells, which have received less attention than waves generated by cyclones. To accurately simulate sea states in tropical areas, we implemented the spectral wave model WAVEWATCH III© (WW3) over a global unstructured grid with a spatial resolution ranging from 50 km to 100 m. The model is forced by ERA5 wind fields, corrected for negative biases through a quantile–quantile approach based on satellite radiometer data. The wind input source terms adjusted accordingly and the explicit representation of tropical islands result in improved predictive skills in the tropical ocean. Moreover, this new simulation allows for the first time direct comparisons with the in situ data collected on volcanic islands at water depths ranging from 10 to 30 m, which corresponds to a few hundred meters from the shore
Trophic niche differentiation and foraging plasticity of long-finned pilot whales (Globicephala melas edwardii) in Tasmanian waters: insights from isotopic analysis
No full textInternational audienceUnderstanding the foraging preference of cetaceans is crucial for assessing their role as apex predators and indicators of marine ecosystem health. Using stable isotope analysis, we investigated trophic niche differentiation and foraging plasticity in 141 long-finned pilot whales ( Globicephala melas edwardii ) that stranded along the Tasmanian coast at three locations (Marion Bay, King Island, and Maria Island). Stranding location accounted for most of the variability in skin isotopic values ( δ 13 C: - 17.9 ± 0.2 ‰ to –16.9 ± 0.2 ‰, Principal Coordinate 1 = 89%), likely reflecting differences in foraging habitats. In addition, isotopic niche overlap ranged from minimal (0-10% between Marion Bay and Maria Island) to moderate (between Marion Bay and King Island, and King Island and Maria Island). While sex related differences in isotopic niche space were minimal overall, there was some variability in the core niche space between males and females at Maria Island. Dietary proportions from our mixing model support a predominantly cephalopod diet for pilot whales in Tasmanian waters (91%, CI: 63-90%), with greater contributions from offshore dietary sources (68%, CI: 25-95%). The dietary variability across the three strandings highlights the foraging plasticity of pilot whales, which despite their preferences for a wide range of oceanic cephalopods, can adopt a more generalist feeding strategy when necessary. These findings provide valuable insights into the ecological role and adaptability of pilot whales in Tasmanian waters, highlighting the importance of monitoring apex predators to inform conservation and ecosystem management strategies in dynamic marine ecosystems
Dynamics of Infragravity Waves Across the Southern Reef Barrier of Mayotte, Indian Ocean
No full textInternational audienceDue to climate change, tropical islands are being increasingly exposed to coastal hazards. Under energetic incident swells, infragravity (IG) waves can have a key contribution to extreme water levels and flooding, but their dynamics at barrier reef remains little studied. In this context, this study analyses IG wave generation mechanisms and transformations across a barrier reef to the southwest of Mayotte (Indian Ocean), combining a new comprehensive field dataset with phase resolving wave modelling. This analysis reveals that IG waves are mostly breakpoint-forced and suffer a substantial dissipation by bottom friction, particularly at low tide. Numerical experiments with reduced bottom friction representing a degraded coral reef suggest that IG waves would grow by about 20% across the reef at high tide. This study highlights the key role of coral reefs to dissipate IG waves and hence limit extreme water levels and subsequent coastal hazards.</div
A novel airflow zonal model for urban microclimate modelling at the block scale
No full textInternational audienc
La plantez - Édition, traduction et notes d'après le manuscrit de Bern, Burgerbibliothek, Cod. 354
No full textÉdition, traduction et notes de La plantez d'après le manuscrit de Bern, Burgerbibliothek, Cod. 35
L'espervier - Édition, traduction et notes d'après le manuscrit BnF NAF 1104
No full textÉdition, traduction et notes de L'espervier d'après le ms. BnF NAF 110
Les trois dames qui troverent l'anel 1 - Édition, traduction et notes d'après le ms. BnF fr. 837
No full textÉdition, traduction et notes des Trois dames qui troverent l'anel 1 d'après le ms. BnF fr. 83
Establishing bio-logging data collections as dynamic archives of animal life on Earth
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Guide méthodologique : évaluer les solutions d'adaptation au changement climatique fondées sur la nature
No full textCette méthodologie d’évaluation a été conçue dans le cadre du projet de recherche ADAPTOM, soutenu par la Fondation de France (2022-2026) et appliquée à 26 projets déployés Outre-Mer.En 2025-2026, cette méthodologie d’évaluation sera à nouveau utilisée dans le cadre du projet de recherche ADAPTNAT, financé par l’Agence française de développement dans le cadre de son programme AdaptAction dont la Phase 2 porte sur l’océan Indien, pour évaluer les projets de SafN déployés à Maurice, aux Comores et à Madagascar.En complément, sur la période 2025-2028, cette méthodologie d’évaluation sera appliquée à différents projets d’adaptation côtière déployés dans l’océan Pacifique, dans le cadre de deux projets de recherche : (1) le projet PPR Océan et Climat FUTURISKS France 2030 (2022- 2028), coordonné par Virginie Duvat et Xavier Bertin, UMRi LIENSs, La Rochelle Université- CNRS ; et (2) le projet « Évaluation de l’adaptation côtière au changement climatique : application aux Petites îles tropicales » développé par Virginie Duvat dans le cadre d’une Chaire Senior Innovation à l’Institut Universitaire de France.Cette méthodologie d’évaluation a déjà fait l’objet de différentes formes d’utilisation et de valorisation :- Utilisation par le Ministère de la Transition Écologique et de la Cohésion des Territoires (MTECT) pour évaluer les projets candidats au 2ème AAP national SfN « Des solutions fondées sur la nature pour adapter les territoires côtiers à l’érosion » en 2024.- Utilisation par des acteurs opérationnels impliqués dans le financement et la mise en œuvre de SafN