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Author Alain Royer, Florent Domine, Alexandre Roy, Alexandre Langlois, Nicolas Marchand, Gautier Davesne
Title New northern snowpack classification linked to vegetation cover on a latitudinal mega-transect across northeastern Canada Type Journal
Year 2021 Publication Écoscience Abbreviated Journal
Volume Issue Pages 1-18
Keywords classification de la couverture de neige Gradient latitudinal interactions neige-végétation Latitudinal gradient propriétés de la neige snow cover classification snow–vegetation interaction snowpack properties
Abstract Changes in mass, extent, duration, and physical properties of snow are key elements for studying associated climate change feedbacks in northern regions. In this study, we analyzed snowpack physical properties along a ‘mega’ transect from 47°N to 83°N (4,000 km) in northeastern Canada, which includes marked transitions between ecozones from boreal forest to subarctic and arctic ecosystems. Our unique dataset of 391 detailed snowpits acquired over the last 20 years, complemented with snow data from weather stations, shows that snowpack properties such as snow water equivalent, snow depth, density, grain size and basal depth hoar fraction (DHF) are strongly linked to vegetation type. Based on these results, we propose an updated classification of snow types in three classes: boreal forest snow (47–58°N), tundra snow (58–74°N) and polar desert snow (74–83°N), which is more appropriate to the study area than the general north hemisphere classification commonly used. We also show that shrub presence along the transect contributes to a significant increase in DHF development which contributes most strongly to the thermal insulation properties of the snowpack. Overall, our analysis suggests that snow–vegetation interactions have a positive feedback effect on warming at northern latitudes.
Programme (up) 1042
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 1195-6860 ISBN 1195-6860 Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 7971
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Author Mathilde Poirier, Dominique Fauteux, Gilles Gauthier, Florent Domine, Jean-François Lamarre
Title Snow hardness impacts intranivean locomotion of arctic small mammals Type Journal
Year 2021 Publication Ecosphere Abbreviated Journal
Volume 12 Issue 11 Pages e03835
Keywords Arctic burrowing behavior digging fossorial hardness lemming locomotion rain-on-snow rodent snow subnivean tunnel
Abstract Fossorial locomotion is often considered as the most energetically costly of all terrestrial locomotion. Small arctic rodents, such as lemmings, dig tunnels not only in the soil but also through the snowpack, which is present for over 8 months of the year. Lemmings typically dig in the softest snow layer called the depth hoar but with climate change, melt-freeze and rain-on-snow (ROS) events are expected to increase in the Arctic, leading to a higher frequency of hardened snowpacks. We assessed the impacts of snow hardness on the locomotion of two lemming species showing different morphological adaptations for digging. We hypothesized that an increase in snow hardness would (1) decrease lemming performance and (2) increase their effort while digging, but those responses would differ between lemming species. We exposed four brown lemmings (Lemmus trimucronatus) and three collared lemmings (Dicrostonyx groenlandicus) to snow of different hardness (soft, hard, and ROS) during 30-min trials (n = 63 trials) in a cold room and filmed their behavior. We found that the digging speed and tunnel length of both species decreased with snow hardness and density, underlining the critical role of snow properties in affecting lemming digging performance. During the ROS trials, time spent digging by lemmings increased considerably and they also started using their incisors to help break the hard snow, validating our second hypothesis. Overall, digging performance was higher in collared lemmings, the species showing more morphological adaptations to digging, than in brown lemmings. We conclude that the digging performance of lemming is highly dependent on snowpack hardness and that the anticipated increase in ROS events may pose a critical energetic challenge for arctic rodent populations.
Programme (up) 1042
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2150-8925 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8028
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Author Guillaume Schwob, Nicolás I. Segovia, Claudio González-Wevar, Léa Cabrol, Julieta Orlando, Elie Poulin
Title Exploring the Microdiversity Within Marine Bacterial Taxa: Toward an Integrated Biogeography in the Southern Ocean Type Journal
Year 2021 Publication Frontiers in Microbiology Abbreviated Journal
Volume 12 Issue Pages 1985
Keywords
Abstract Most of the microbial biogeographic patterns in the oceans have been depicted at the whole community level, leaving out finer taxonomic resolution (i.e., microdiversity) that is crucial to conduct intra-population phylogeographic study, as commonly done for macroorganisms. Here, we present a new approach to unravel the bacterial phylogeographic patterns combining community-wide survey by 16S rRNA gene metabarcoding and intra-species resolution through the oligotyping method, allowing robust estimations of genetic and phylogeographic indices, and migration parameters. As a proof-of-concept, we focused on the bacterial genus Spirochaeta across three distant biogeographic provinces of the Southern Ocean; maritime Antarctica, sub-Antarctic Islands, and Patagonia. Each targeted Spirochaeta operational taxonomic units were characterized by a substantial intrapopulation microdiversity, and significant genetic differentiation and phylogeographic structure among the three provinces. Gene flow estimations among Spirochaeta populations support the role of the Antarctic Polar Front as a biogeographic barrier to bacterial dispersal between Antarctic and sub-Antarctic provinces. Conversely, the Antarctic Circumpolar Current appears as the main driver of gene flow, connecting sub-Antarctic Islands with Patagonia and maritime Antarctica. Additionally, historical processes (drift and dispersal limitation) govern up to 86% of the spatial turnover among Spirochaeta populations. Overall, our approach bridges the gap between microbial and macrobial ecology by revealing strong congruency with macroorganisms distribution patterns at the populational level, shaped by the same oceanographic structures and ecological processes.
Programme (up) 1044
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN 1664-302X ISBN 1664-302X Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6457
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Author Van Hanja J
Title Caractérisation des habitats marins benthiques en zones côtières aux Iles Kerguelen par analyse d'images sous-marines Type Master 1
Year 2021 Publication Master 1 Océanographie, Université de Liège Abbreviated Journal
Volume Issue Pages 10 pp
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Programme (up) 1044
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Notes Approved yes
Call Number Serial 8062
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Author Meudec L.
Title Analyse de la diversité des astéries du Plateau des Kerguelen par approches génétique et morphologique et modélisation des habitats Type Master 2
Year 2021 Publication Master 2 Sciences de la Mer, Sorbonne Universités Abbreviated Journal
Volume Issue Pages 50 pp
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Programme (up) 1044
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Area Expedition Conference
Notes Approved yes
Call Number Serial 8063
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Author Pierre-Yves Pascal, Yann Reynaud, Elie Poulin, Chantal De Ridder, Thomas Saucede
Title Feeding in spatangoids: the case of Abatus Cordatus in the Kerguelen Islands (Southern Ocean) Type Journal
Year 2021 Publication Polar Biology Abbreviated Journal
Volume 44 Issue 4 Pages 795-808
Keywords
Abstract Irregular urchins exclusively live in marine soft bottom habitats, dwelling either upon or inside sediments and selectively picking up sediment grains and organic particles, or swallowing bulk sediment to feed on the associated organic matter. The exact food source and dietary requirements of most irregular echinoids, however, remain incompletely understood. The schizasterid species Abatus cordatus (Verrill, 1876) is a sub-Antarctic spatangoid that is endemic to the Kerguelen. The feeding behaviour of A. cordatus was investigated using simultaneously metabarcoding and stable isotope approaches. Comparison of ingested and surrounding sediments by metabarcoding revealed a limited selective ingestion of prokaryotes and eukaryotes by the urchin. Compared to surrounding sediments, the gut content had (i) higher carbon and nitrogen concentrations potentially due to selective ingestion of organic matter and/or the sea urchin mucus secretion and (ii) δ15N enrichment due to the selective assimilation of lighter isotope in the gut. Feeding experiments were performed using 13C and 15 N-enriched sediments in aquariums. The progression of stable isotope enrichment in proximal and distal parts of the digestive track of A. cordatus revealed that all particles are not similarly transported likely due to siphon functioning. Ingestion of water with associated dissolved and particulate organic matter should play an important role in urchin nutrition. A. cordatus had a gut resident time fluctuating between 76 and 101 h and an ingestion rate of 36 mg dry sediment h−1 suggesting that dense populations of the species may play a key ecological role through bioturbation in soft bottom shallow-water habitats of the Kerguelen Islands.
Programme (up) 1044
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1432-2056 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8000
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Author Margot Arnould-Pétré, Charlène Guillaumot, Bruno Danis, Jean-Pierre Féral, Thomas Saucède
Title Individual-based model of population dynamics in a sea urchin of the Kerguelen Plateau (Southern Ocean), Abatus cordatus, under changing environmental conditions Type Journal
Year 2021 Publication Ecological Modelling Abbreviated Journal
Volume 440 Issue Pages 109352
Keywords Climate change Dynamic energy budget Ecological modelling Endemic echinoderm Individual-based model Kerguelen Model sensitivity
Abstract The Kerguelen Islands are part of the French Southern Territories, located at the limit of the Indian and Southern oceans. They are highly impacted by climate change, and coastal marine areas are particularly at risk. Assessing the responses of species and populations to environmental change is challenging in such areas for which ecological modelling can constitute a helpful approach. In the present work, a DEB-IBM model (Dynamic Energy Budget – Individual-Based Model) was generated to simulate and predict population dynamics in an endemic and common benthic species of shallow marine habitats of the Kerguelen Islands, the sea urchin Abatus cordatus. The model relies on a dynamic energy budget model (DEB) developed at the individual level. Upscaled to an individual-based population model (IBM), it then enables to model population dynamics through time as a result of individual physiological responses to environmental variations. The model was successfully built for a reference site to simulate the response of populations to variations in food resources and temperature. Then, it was implemented to model population dynamics at other sites and for the different IPCC climate change scenarios RCP 2.6 and 8.5. Under present-day conditions, models predict a more determinant effect of food resources on population densities, and on juvenile densities in particular, relative to temperature. In contrast, simulations predict a sharp decline in population densities under conditions of IPCC scenarios RCP 2.6 and RCP 8.5 with a determinant effect of water warming leading to the extinction of most vulnerable populations after a 30-year simulation time due to high mortality levels associated with peaks of high temperatures. Such a dynamic model is here applied for the first time to a Southern Ocean benthic and brooding species and offers interesting prospects for Antarctic and sub-Antarctic biodiversity research. It could constitute a useful tool to support conservation studies in these remote regions where access and bio-monitoring represent challenging issues.
Programme (up) 1044
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Corporate Author Thesis
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3800 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8002
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Author Daniela Levicoy, Sebastián Rosenfeld, Leyla Cárdenas
Title Divergence time and species delimitation of microbivalves in the Southern Ocean: the case of Kidderia species Type Journal
Year 2021 Publication Polar Biology Abbreviated Journal
Volume 44 Issue 7 Pages 1365-1377
Keywords
Abstract The systematics of Subantarctic and Antarctic near-shore marine benthic invertebrates requires major revision and highlights the necessity to incorporate additional sources of information in the specimen identification chart in the Southern Ocean (SO). In this study, we aim to improve our understanding of the biodiversity of Kidderia (Dall 1876) through molecular and morphological comparisons of Antarctic and Subantarctic taxa. The microbivalves of the genus Kidderia are small brooding organisms that inhabit intertidal and shallow subtidal rocky ecosystems. This genus represents an interesting model to test the vicariance and dispersal hypothesis in the biogeography of the SO. However, the description of Kidderia species relies on a few morphological characters and biogeographic records that raise questions about the true diversity in the group. Here we will define the specimens collected with genetic tools, delimiting their respective boundaries across provinces of the SO, validating the presence of two species of Kidderia. Through the revision of taxonomic issues and species delimitation, it was possible to report that the Antarctic species is Kidderia subquadrata and the species recorded in the Subantarctic islands Diego Ramirez, South Georgia and the Kerguelen Archipelago is Kidderia minuta. The divergence time estimation suggests the origin and diversification of Kidderia lineages are related to historical vicariant processes probably associated with the separation of the continental landmasses close to the late Eocene.
Programme (up) 1044
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1432-2056 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8004
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Author Zambra López-Farrán, Charlène Guillaumot, Luis Vargas-Chacoff, Kurt Paschke, Valérie Dulière, Bruno Danis, Elie Poulin, Thomas Saucède, Jonathan Waters, Karin Gérard
Title Is the southern crab Halicarcinus planatus (Fabricius, 1775) the next invader of Antarctica? Type Journal
Year 2021 Publication Global Change Biology Abbreviated Journal
Volume 27 Issue 15 Pages 3487-3504
Keywords climate change establishment niche modelling non-native species reptant crab Southern Ocean survival thermotolerance
Abstract The potential for biological colonization of Antarctic shores is an increasingly important topic in the context of anthropogenic warming. Successful Antarctic invasions to date have been recorded exclusively from terrestrial habitats. While non-native marine species such as crabs, mussels and tunicates have already been reported from Antarctic coasts, none have as yet established there. Among the potential marine invaders of Antarctic shallow waters is Halicarcinus planatus (Fabricius, 1775), a crab with a circum-Subantarctic distribution and substantial larval dispersal capacity. An ovigerous female of this species was found in shallow waters of Deception Island, South Shetland Islands in 2010. A combination of physiological experiments and ecological modelling was used to assess the potential niche of H. planatus and estimate its future southward boundaries under climate change scenarios. We show that H. planatus has a minimum thermal limit of 1°C, and that its current distribution (assessed by sampling and niche modelling) is physiologically restricted to the Subantarctic region. While this species is presently unable to survive in Antarctica, future warming under both ‘strong mitigation’ and ‘no mitigation’ greenhouse gas emission scenarios will favour its niche expansion to the Western Antarctic Peninsula (WAP) by 2100. Future human activity also has potential to increase the probability of anthropogenic translocation of this species into Antarctic ecosystems.
Programme (up) 1044
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-2486 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8005
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Author Le Moan E
Title Utilisation de modèles mixtes pour décrire la réponse de l’oursin spatangue Abatus cordatus (Verrill, 1876), espèce endémique des Kerguelen, aux changements environnementaux Type Master 1
Year 2021 Publication Master 1 Sciences de la Mer, Sorbonne Universités Abbreviated Journal
Volume Issue Pages 15 pp
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Abstract
Programme (up) 1044
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 8069
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