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Loïc Teulier, Benjamin Rey, Jérémy Tornos, Marion Le Coadic, Pierre-Axel Monternier, Aurore Bourguignon, Virginie Dolmazon, Caroline Romestaing, Jean-Louis Rouanet, Claude Duchamp, Damien Roussel |
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Title |
Lipid-induced thermogenesis is up-regulated by the first cold-water immersions in juvenile penguins |
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Journal |
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Year |
2016 |
Publication |
Journal of Comparative Physiology B |
Abbreviated Journal |
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Volume |
186 |
Issue |
5 |
Pages |
639-650 |
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Keywords  |
Energy substrates Metabolism Mitochondria Oxidative phosphorylation efficiency Skeletal muscle |
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Abstract |
The passage from shore to marine life is a critical step in the development of juvenile penguins and is characterized by a fuel selection towards lipid oxidation concomitant to an enhancement of lipid-induced thermogenesis. However, mechanisms of such thermogenic improvement at fledging remain undefined. We used two different groups of pre-fledging king penguins (Aptenodytes patagonicus) to investigate the specific contribution of cold exposure during water immersion to lipid metabolism. Terrestrial penguins that had never been immersed in cold water were compared with experimentally cold-water immersed juveniles. Experimentally immersed penguins underwent ten successive immersions at approximately 9–10 °C for 5 h over 3 weeks. We evaluated adaptive thermogenesis by measuring body temperature, metabolic rate and shivering activity in fully immersed penguins exposed to water temperatures ranging from 12 to 29 °C. Both never-immersed and experimentally immersed penguins were able to maintain their homeothermy in cold water, exhibiting similar thermogenic activity. In vivo, perfusion of lipid emulsion at thermoneutrality induced a twofold larger calorigenic response in experimentally immersed than in never-immersed birds. In vitro, the respiratory rates and the oxidative phosphorylation efficiency of isolated muscle mitochondria were not improved with cold-water immersions. The present study shows that acclimation to cold water only partially reproduced the fuel selection towards lipid oxidation that characterizes penguin acclimatization to marine life. |
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131 |
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ISSN |
1432-136X |
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1432-136X |
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yes |
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Serial |
7220 |
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Thomas Merkling, Scott A. Hatch, Sarah Leclaire, Etienne Danchin, Pierrick Blanchard |
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Title |
Offspring sex-ratio and environmental conditions in a seabird with sex-specific rearing costs: a long-term experimental approach |
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Journal |
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Year |
2019 |
Publication |
Evolutionary Ecology |
Abbreviated Journal |
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Volume |
33 |
Issue |
3 |
Pages |
417-433 |
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Keywords |
Energy expenditure Life-history trade-off Oceanographic conditions Parental effort Reproductive cost |
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Abstract |
Sex allocation studies among birds and mammals are notoriously inconsistent with theoretical predictions. One explanation is the difficulty of collecting data on costs and benefits of sex-ratio adjustments, which prevents the investigation of underlying assumptions. Some predictions may thus have been tested in species where they should not have been expected. Here, we focus on the “cost of reproduction hypothesis”, which states that parents with low investment capacity should avoid producing the most expensive sex to minimise the decrease in their residual reproductive value. In the black-legged kittiwake (Rissa tridactyla), sons are energetically more expensive than daughters. Using 10 years of data (1172 chicks from 790 broods) from a long-term feeding experiment, we predicted a stronger decrease in the probability of producing a son with deteriorating environmental conditions among Control than among supplementally Fed parents. To test this prediction, we used three proxies of environmental conditions and a recent sliding window approach. We found no support for our prediction. Hence, we investigated between-year sex-ratio variation in relation to feeding status to detect a response to an unmeasured environmental variable. There was no interaction between year and feeding status, nor any effect of feeding status itself. However, the probability of producing a male increased with time, which could be a response to an oceanic regime shift that occurred around our colony, but that our proxies failed to capture. Our study further highlights the difficulty of explaining sex-ratio variation in long-lived species with complex life-histories where multiple selective pressures can occur simultaneously. |
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1162 |
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ISSN |
1573-8477 |
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yes |
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Serial |
8396 |
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Author |
Van der Putten Nathalie, Verbruggen Cyriel, Ochyra Ryszard, Verleyen Elie, Frenot Yves, |
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Title |
Subantarctic flowering plants: pre-glacial survivors or post-glacial immigrants?
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Type |
Journal Article |
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Year |
2010 |
Publication |
Journal of Biogeography |
Abbreviated Journal |
J. Biogeogr. |
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Volume |
37 |
Issue |
3 |
Pages |
582 -592 |
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Keywords |
Endemism, glacial refugia, LGM ice cover, palaeobotany, phanerogamic flora, post-glacial immigration, pre-LGM survivors, regionalism, subantarctic islands, |
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Abstract |
Abstract Aim The aim here was to assess whether the present-day assemblage of subantarctic flowering plants is the result of a rapid post-Last Glacial Maximum (LGM) colonization or whether subantarctic flowering plants survived on the islands in glacial refugia throughout the LGM. Location The circumpolar subantarctic region, comprising six remote islands and island groups between latitudes 46° and 55° S, including South Georgia in the South Atlantic Ocean, the Prince Edward Islands, Îles Crozet, Îles Kerguelen, the Heard Island group in the South Indian Ocean and Macquarie Island in the South Pacific Ocean. Methods Floristic affinities between the subantarctic islands were assessed by cluster analysis applied to an up-to-date dataset of the phanerogamic flora in order to test for the existence of provincialism within the subantarctic. A review of the primary literature on the palaeobotany, geology and glacial history of the subantarctic islands was carried out and supplemented with additional palaeobotanical data and new field observations from South Georgia, Île de la Possession (Îles Crozet) and Îles Kerguelen. Results First, a strong regionalism was observed, with different floras characterizing the islands in each of the ocean basins, and endemic species being present in the South Indian Ocean and South Pacific Ocean provinces. Second, the majority of the plant species were present at the onset of accumulation of post-glacial organic sediment and there is no evidence for the natural arrival of new immigrants during the subsequent period. Third, a review of geomorphological data suggested that the ice cover was incomplete during the LGM on the majority of the islands, and ice-free biological refugia were probably present even on the most glaciated islands. Main conclusions Several independent lines of evidence favour the survival of a native subantarctic phanerogamic flora in local refugia during the LGM rather than a post-LGM colonization from more distant temperate landmasses in the Southern Hemisphere.
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136 |
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Blackwell Publishing Ltd |
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ISSN |
1365-2699 |
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yes |
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Serial |
75 |
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Author |
S. Véron, A. Bernard, E. Lebreton, C. Rodrigues-Vaz, M. Durand, L. Procopio, M. Hélion, M. Gayot, G. Viscardi, G. A. Krupnick, C. M. S. Carrington, V. Boullet, B. Mallet, A. Dimassi, T. Pailler, J. Hivert, M. Lebouvier, P. Agnola, D. Bruy, G. Gateblé, G. Lannuzel, S. Meyer, O. Gargominy, G. Gigot, V. Invernon, S. Leblond, M. Pignal, S. Tercerie, S. Muller, G. Rouhan |
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Title |
Pre-assessments of plant conservation status in islands: the case of French Overseas Territories |
Type |
Journal |
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Year |
2023 |
Publication |
Biodiversity and Conservation |
Abbreviated Journal |
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Volume |
32 |
Issue |
4 |
Pages |
1165-1187 |
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Keywords |
Endemics French overseas territories Islands Pre-assessments Red List Tracheophytes |
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Abstract |
Assessment methods have been developed to estimate a preliminary conservation status for species and subsequently to facilitate the building of Red Lists. Such pre-assessment methods could be particularly useful in the French Overseas Territories (FOTs) where Red Lists tend to be out-dated or absent and where a high number of endemic species face detrimental anthropogenic pressures. We first aimed to conduct a preliminary assessment (hereafter, pre-assessment) of the conservation status of endemic plants from Guadeloupe, Martinique, Réunion, Mayotte, French sub-Antarctic islands, New Caledonia, and Scattered Islands. We then compared the various methods used in conducting the pre-assessment and discussed ways to adapt these methods to small territories. We compiled occurrence data of endemic species identified thanks to a previous taxonomic work and pre-assessed their conservation status under Red List criteria A and B and the use of a Random Forest algorithm. We then measured the accuracy, specificity, and sensitivity of each method based on existing Red Lists. The Random Forest algorithm and a method based on range-size performed best at correctly attributing conservation status. Using these pre-assessment methods, we estimated that up to 60% of the endemic flora of the FOTs is potentially threatened. Range restriction but also anthropogenic pressures were key factors that explained these risks. Pre-assessment methods are useful tools to get a first measure of species conservation status. These methods should be adapted to the territories considered and their conservation issues in order to reach a good performance. |
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136 |
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ISSN |
1572-9710 |
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yes |
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Call Number |
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Serial |
8634 |
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Author |
Sara Labrousse, Alexander D. Fraser, Michael Sumner, Takeshi Tamura, David Pinaud, Barbara Wienecke, Roger Kirkwood, Yan Ropert‐Coudert, Ryan Reisinger, Ian Jonsen, Rick Porter‐Smith, Christophe Barbraud, Charles-André Bost, Rubao Ji, Stéphanie Jenouvrier |
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Title |
Dynamic Fine-Scale Sea Icescape Shapes Adult Emperor Penguin Foraging Habitat in East Antarctica |
Type |
Journal |
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Year |
2019 |
Publication |
Geophysical Research Letters |
Abbreviated Journal |
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Volume |
46 |
Issue |
20 |
Pages |
11206-11218 |
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Keywords |
emperor penguin fast ice foraging ecology iceberg polynya sea ice |
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Abstract |
The emperor penguin, an iconic species threatened by projected sea ice loss in Antarctica, has long been considered to forage at the fast ice edge, presumably relying on large/yearly persistent polynyas as their main foraging habitat during the breeding season. Using newly developed fine-scale sea icescape data and historical penguin tracking data, this study for the first time suggests the importance of less recognized small openings, including cracks, flaw leads and ephemeral short-term polynyas, as foraging habitats for emperor penguins. The tracking data retrieved from 47 emperor penguins in two different colonies in East Antarctica suggest that those penguins spent 23% of their time in ephemeral polynyas and did not use the large/yearly persistent, well-studied polynyas, even if they occur much more regularly with predictable locations. These findings challenge our previous understanding of emperor penguin breeding habitats, highlighting the need for incorporating fine-scale seascape features when assessing the population persistence in a rapidly changing polar environment. |
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Programme |
109,394,1091 |
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Bachelor's thesis |
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ISSN |
1944-8007 |
ISBN |
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Approved |
yes |
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Call Number |
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Serial |
7636 |
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| Permanent link to this record |
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Author |
Songtao Ai, Xi Ding, Florian Tolle, Zemin Wang, Xi Zhao |
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Title |
Latest Geodetic Changes of Austre Lovénbreen and Pedersenbreen, Svalbard |
Type |
Journal |
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Year |
2019 |
Publication |
Remote Sensing |
Abbreviated Journal |
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Volume |
11 |
Issue |
24 |
Pages |
2890 |
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Keywords |
elevation change glacier retreat mass balance snow depth surface DEM |
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Abstract |
Geodetic mass changes in the Svalbard glaciers Austre Lovénbreen and Pedersenbreen were studied via high-precision real-time kinematic (RTK)-global positioning system (GPS) measurements from 2013 to 2015. To evaluate the elevation changes of the two Svalbard glaciers, more than 10,000 GPS records for each glacier surface were collected every year from 2013 to 2015. The results of several widely used interpolation methods (i.e., inverse distance weighting (IDW), ordinary kriging (OK), universal kriging (UK), natural neighbor (NN), spline interpolation, and Topo to Raster (TTR) interpolation) were compared. Considering the smoothness and accuracy of the glacier surface, NN interpolation was selected as the most suitable interpolation method to generate a surface digital elevation model (DEM). In addition, we compared two procedures for calculating elevation changes: using DEMs generated from the direct interpolation of the RTK-GPS points and using the elevation bias of crossover points from the RTK-GPS tracks in different years. Then, the geodetic mass balances were calculated by converting the elevation changes to their water equivalents. Comparing the geodetic mass balances calculated with and without considering snow depth revealed that ignoring the effect of snow depth, which differs greatly over a short time interval, might lead to bias in mass balance investigation. In summary, there was a positive correlation between the geodetic mass balance and the corresponding elevation. The mass loss increased with decreasing elevation, and the mean annual gradients of the geodetic mass balance along the elevation of Austre Lovénbreen and Pedersenbreen in 2013–2015 were approximately 2.60‰ and 2.35‰, respectively. The gradients at the glacier snouts were three times larger than those over the whole glaciers. Additionally, some mass gain occurred in certain high-elevation regions. Compared with a 2019 DEM generated from unmanned aerial vehicle measurement, the glacier snout areas presented an accelerating thinning situation in 2015–2019. |
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Programme |
1108 |
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yes |
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Serial |
7710 |
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Author |
N. Aubone, M. Saraceno, M. L. Torres Alberto, J. Campagna, L. Le Ster, B. Picard, M. Hindell, C. Campagna, C. R. Guinet |
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Title |
Physical changes recorded by a deep diving seal on the Patagonian slope drive large ecological changes |
Type |
Journal |
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Year |
2021 |
Publication |
Journal of Marine Systems |
Abbreviated Journal |
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Volume |
223 |
Issue |
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Pages |
103612 |
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Keywords |
Elephant seals Malvinas current Patagonian shelf slope Southwestern Atlantic Ocean |
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Abstract |
The Patagonian slope is the region where Subantarctic waters and bathymetry give raise to physical and ecological processes that support a rich biodiversity and a large-scale industrial fisheries. Unique among the species that depend on this region is the deep diving southern elephant seal, Mirounga leonina. We report here on changes in the foraging behavior of a female seal explained by the combined effect of a cold and high salinity water mass and a decrease in surface chlorophyll-a concentration. Behavioral and oceanographic data from about 5000 profiles of temperature, conductivity, pressure, light and prey encounters were collected within an area ranging 59.5–61°W and 46–47.5°S, at depths of 300–700 m, on the Patagonian slope, during November–December 2018. A decrease in temperature (0.15 °C) and an increase in salinity (0.03) was found below the mixed layer, during December. Light data revealed a significant increase of irradiance in December (almost reaching the ocean bottom) associated with a decrease of chlorophyll-a in the upper levels. Concomitantly, the seal had a different diving behavior in December, foraging near the surface at night and close to the bottom during daylight hours. Also, the seal doubled the prey capture attempts in December compared to November. This study reveals the importance of ocean physical properties on seal's diving and foraging behavior, and how this changes, although small, can impact on seals diet and body composition during their post-breeding trips. |
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1201 |
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ISSN |
0924-7963 |
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yes |
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Serial |
8771 |
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Author |
A. Marchaudon, P.-L. Blelly, M. Grandin, A. Aikio, A. Kozlovsky, I. Virtanen |
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Title |
IPIM Modeling of the Ionospheric F2 Layer Depletion at High Latitudes During a High-Speed Stream Event |
Type |
Journal |
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Year |
2018 |
Publication |
Journal of Geophysical Research: Space Physics |
Abbreviated Journal |
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Volume |
123 |
Issue |
8 |
Pages |
7051-7066 |
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Keywords |
EISCAT high-speed stream ionosondes SuperDARN |
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Abstract |
Our aim is to understand the effect of high-speed stream events on the high-latitude ionosphere and more specifically the decrease of the foF2 frequency during the entire day following the impact. First, we have selected one summertime event, for which a large data set was available: Super Dual Auroral Radar Network (SuperDARN) and European Incoherent SCATter (EISCAT) radars, Tromsø and Sodankylä ionosondes, and the CHAllenging Minisatellite Payload (CHAMP) satellite. We modeled with the IPIM model (IRAP Plasmasphere Ionosphere Model) the dynamics of the ionosphere at Tromsø and Sodankylä using inputs derived from the data. The simulations nicely match the measurements made by the EISCAT radar and the ionosondes, and we showed that the decrease of foF2 is associated with a transition from F2 to F1 layer resulting from a decrease of neutral atomic oxygen concentration. Modeling showed that electrodynamics can explain short-term behavior on the scale of a few hours, but long-term behavior on the scale of a few days results from the perturbation induced in the atmosphere. Enhancement of convection is responsible for a sharp increase of the ion temperature by Joule heating, leading through chemistry to an immediate reduction of the F2 layer. Then, ion drag on neutrals is responsible for a rapid heating and expansion of the thermosphere. This expansion affects atomic oxygen through nonthermal upward flow, which results in a decrease of its concentration and amplifies the decrease of [O]/[N2] ratio. This thermospheric change explains long-term extinction of the F2 layer. |
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312 |
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ISSN |
2169-9402 |
ISBN |
2169-9402 |
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yes |
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Call Number |
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Serial |
7362 |
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Author |
Gonzáles-Solís J, Shaffer SA, |
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Title |
Introduction and synthesis: spatial ecology of seabirds at sea
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Type |
Journal Article |
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Year |
2009 |
Publication |
Mar Ecol Prog Ser |
Abbreviated Journal |
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Volume |
391 |
Issue |
391 |
Pages |
117 -120 |
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Keywords |
Ecosystems · Impacts · Marine · Seabirds · Spatiotemporal dynamics · Tracking |
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Abstract |
The spatial ecology of seabirds has greater precedence today than ever before because of impacts on the marine environment from human exploitation, pollution, and climate change. Specific life history traits make seabirds particularly sensitive to these impacts, currently driving many species to unsustainable population declines. To evaluate the risk posed by human activities, we need integrative studies on seabird abundance, distributions, and movements in relation to the biophysical marine environment. Also interpreting the limits of these relationships is fundamental to understanding historical constraints and behavioural adaptations of seabirds that are shaped by evolutionary processes. In this Theme Section, we assembled 4 review papers and 10 case studies that highlight some of the latest techniques to study seabird spatial ecology. This includes the application of tracking tags, ship-based surveys, and remotely sensed environmental data, to characterize seabird movement patterns, fine scale behaviour, and overall distribution combined with measures of the oceanic habitats to enhance our understanding of the functional role that seabirds play. Overall, this knowledge is crucial for understanding and predicting the impacts that fisheries, climate change and pollution are exerting on marine ecosystems and will provide opportunities for developing marine protected areas, conservation action plans and species management. |
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333 |
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yes |
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2005 |
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Author |
Cotté Cédric, Dragon Anne-Cécile, Guinet Christophe, Lévy Marina, |
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Title |
Flexible preference of southern elephant seals for distinct mesoscale features within the Antarctic Circumpolar Current
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Type |
Journal Article |
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Year |
2015 |
Publication |
Progress in Oceanography |
Abbreviated Journal |
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Volume |
131 |
Issue |
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Pages |
46-58 |
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Keywords |
Ecosystem, Elephant seal, Mesoscale, Southern ocean, Top predators, |
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Abstract |
The open ocean is a highly variable environment where marine top predators are thought to require optimized foraging strategies to locate and capture prey. Mesoscale and sub-mesoscale features are known to effect planktonic organisms but the response of top predators to these features results from behavioural choices and is poorly understood. Here, we investigated a multi-year database of at-sea distribution and behaviour of female Southern elephant seals (Mirounga leonina) to identify their preference for specific structures within the intense eddy field of the dynamic Antarctic Circumpolar Current (ACC). We distinguished two behavioural modes, i.e. travelling and intensive foraging, using state-space modelling. We employed multisatellite Lagrangian diagnostics to describe properties of (sub-)mesoscale oceanic circulation. Statistical analyses (GAMMs and Student’s t-tests) revealed relationships between elephant seal behaviour and (sub-)mesoscale features during the post-moulting period (January–August): travelling along thermal fronts and intensive foraging in cold and long-lived mesoscale water patches. A Lagrangian analysis suggests that these water patches – where the prey field likely developed and concentrated – corresponded to waters which have supported the bloom during spring. In contrast, no clear preference emerged at the (sub-)mesoscale during the post-breeding period (October–December), although seals were distributed within the Chlorophyll-rich water plume detaching from the plateau. We interpret this difference in terms of a seasonal change in the prey field. Our interdisciplinary approach contributes to elucidate the foraging strategies of top predators in a complex and dynamic environment. It also brings top down insights on prey distribution in remote areas where information on mid-trophic levels are strongly lacking and it identifies important physical-biological interactions relevant for ecosystem modelling and management. |
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0079-6611 |
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yes |
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6174 |
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