| |
Records |
Links |
|
Author |
Neige Calonne, Maurine Montagnat, Margret Matzl, Martin Schneebeli |
|
| |
Title |
The layered evolution of fabric and microstructure of snow at Point Barnola, Central East Antarctica |
Type |
Journal |
| |
Year |
2017 |
Publication |
Earth and Planetary Science Letters |
Abbreviated Journal |
|
|
| |
Volume |
460 |
Issue |
|
Pages |
293-301 |
|
| |
Keywords |
Antarctica c-axis orientation snow microstructure temperature gradient metamorphism |
|
| |
Abstract |
Snow fabric, defined as the distribution of the c-axis orientations of the ice crystals in snow, is poorly known. So far, only one study exits that measured snow fabric based on a statistically representative technique. This recent study has revealed the impact of temperature gradient metamorphism on the evolution of fabric in natural snow, based on cold laboratory experiments. On polar ice sheets, snow properties are currently investigated regarding their strong variability in time and space, notably because of their potential influence on firn processes and consequently on ice core analysis. Here, we present measurements of fabric and microstructure of snow from Point Barnola, East Antarctica (close to Dome C). We analyzed a snow profile from 0 to 3 m depth, where temperature gradients occur. The main contributions of the paper are (1) a detailed characterization of snow in the upper meters of the ice sheet, especially by providing data on snow fabric, and (2) the study of a fundamental snow process, never observed up to now in a natural snowpack, namely the role of temperature gradient metamorphism on the evolution of the snow fabric. Snow samples were scanned by micro-tomography to measure continuous profiles of microstructural properties (density, specific surface area and pore thickness). Fabric analysis was performed using an automatic ice texture analyzer on 77 representative thin sections cut out from the samples. Different types of snow fabric could be identified and persist at depth. Snow fabric is significantly correlated with snow microstructure, pointing to the simultaneous influence of temperature gradient metamorphism on both properties. We propose a mechanism based on preferential grain growth to explain the fabric evolution under temperature gradients. Our work opens the question of how such a layered profile of fabric and microstructure evolves at depth and further influences the physical and mechanical properties of snow and firn. More generally, it opens the way to further studies on the influence of the snow fabric in snow processes related to anisotropic properties of ice such as grain growth, mechanical response, electromagnetic behavior. |
|
| |
Programme |
1052,1150 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
Bachelor's thesis |
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0012-821X |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial  |
8191 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
External influences on the Mertz Glacier Tongue (East Antarctica) in the decade leading up to its calving in 2010 |
Type |
Journal |
| |
Year |
2015 |
Publication |
Journal of Geophysical Research: Earth Surface |
Abbreviated Journal |
|
|
| |
Volume |
120 |
Issue |
3 |
Pages |
490-506 |
|
| |
Keywords |
dynamics glacier tongue grounding icebergs |
|
| |
Abstract |
|
|
| |
Programme |
1050 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
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 |
2169-9011 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8190 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
|
Type |
Journal |
| |
Year |
2017 |
Publication |
Quaternary science reviews |
Abbreviated Journal |
|
|
| |
Volume |
162 |
Issue |
|
Pages |
128-144 |
|
| |
Keywords |
Cl cosmic-ray exposure dating Glacier fluctuations Holocene Kerguelen Late Glacial |
|
| |
Abstract |
|
|
| |
Programme |
1048 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
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 |
0277-3791 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8189 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
Glacier extent in sub-Antarctic Kerguelen archipelago from MIS 3 period: Evidence from 36Cl dating |
Type |
Journal |
| |
Year |
2018 |
Publication |
Quaternary Science Reviews |
Abbreviated Journal |
|
|
| |
Volume |
183 |
Issue |
|
Pages |
110-123 |
|
| |
Keywords |
|
|
| |
Abstract |
|
|
| |
Programme |
1048 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
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 |
0277-3791 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8188 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
Evolution of the Cook Ice Cap (Kerguelen Islands) between the last centuries and 2100 ce based on cosmogenic dating and glacio-climatic modelling |
Type |
Journal |
| |
Year |
2021 |
Publication |
Antarctic Science |
Abbreviated Journal |
|
|
| |
Volume |
33 |
Issue |
3 |
Pages |
301-317 |
|
| |
Keywords |
degree-day glaciological model future projections glacial fluctuations in situ cosmogenic chlorine-36 dating moraines sub-Antarctic islands |
|
| |
Abstract |
The Cook Ice Cap (CIC) on the sub-Antarctic Kerguelen Islands recently experienced extremely negative surface mass balance. Further deglaciation could have important impacts on endemic and invasive fauna and flora. To put this exceptional glacier evolution into a multi-centennial-scale context, we refined the evolution of the CIC over the last millennium, investigated the associated climate conditions and explored its potential evolution by 2100 ce. A glaciological model, constrained by cosmic ray exposure dating of moraines, historical documents and recent direct mass balance observations, was used to simulate the ice-cap extents during different phases of advance and retreat between the last millennium and 2100 ce. Cosmogenic dating suggests glacial advance around the early Little Ice Age (LIA), consistent with findings from other sub-Antarctic studies, and the rather cold and humid conditions brought about by the negative phase of the Southern Annular Mode (SAM). This study contributes to our currently limited understanding of palaeoclimate for the early LIA in the southern Indian Ocean. Glaciological modelling and observations confirm the recent decrease in CIC extent linked to the intensification of the SAM. Although affected by large uncertainties, future simulations suggest a complete disappearance of CIC by the end of the century. |
|
| |
Programme |
1048 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
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 |
0954-1020, 1365-2079 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8187 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
|
Type |
Journal |
| |
Year |
2021 |
Publication |
Antarctic Science |
Abbreviated Journal |
|
|
| |
Volume |
33 |
Issue |
1 |
Pages |
103-115 |
|
| |
Keywords |
Antarctic Cold Reversal glacier fluctuations Holocene in situ cosmogenic chlorine-36 dating palaeoclimate sub-Antarctic |
|
| |
Abstract |
|
|
| |
Programme |
1048 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
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 |
0954-1020, 1365-2079 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8186 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
Regional modeling of surface mass balance on the Cook Ice Cap, Kerguelen Islands (49?S, 69?E) |
Type |
Journal |
| |
Year |
2019 |
Publication |
Climate Dynamics |
Abbreviated Journal |
|
|
| |
Volume |
53 |
Issue |
9 |
Pages |
5909-5925 |
|
| |
Keywords |
|
|
| |
Abstract |
|
|
| |
Programme |
1048 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
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 |
1432-0894 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8185 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
Selecting environmental descriptors is critical for modelling the distribution of Antarctic benthic species |
Type |
Journal |
| |
Year |
2020 |
Publication |
Polar Biology |
Abbreviated Journal |
|
|
| |
Volume |
43 |
Issue |
9 |
Pages |
1363-1381 |
|
| |
Keywords |
|
|
| |
Abstract |
Species distribution models (SDMs) are increasingly used in ecological and biogeographic studies by Antarctic biologists, including for conservation and management purposes. During the modelling process, model calibration is a critical step to ensure model reliability and robustness, especially in the case of SDMs, for which the number of selected environmental descriptors and their collinearity is a recurring issue. Boosted regression trees (BRT) was previously considered as one of the best modelling approach to correct for this type of bias. In the present study, we test the performance of BRT in modelling the distribution of Southern Ocean species using different numbers of environmental descriptors, either collinear or not. Models are generated for six sea star species with contrasting ecological niches and wide distribution ranges over the entire Southern Ocean. For the six studied species, overall modelling performance is not affected by the number of environmental descriptors used to generate models, BRT using the most informative descriptors and minimizing model overfitting. However, removing collinear descriptors also helps reduce model overfitting. Our results confirm that BRTs may perform well and are relevant to deal with complex and redundant environmental information for Antarctic biodiversity distribution studies. Selecting a limited number of non-collinear descriptors before modelling may generate simpler models and facilitate their interpretation. The modelled distributions do not differ noticeably between the different species despite contrasting species ecological niches. This unexpected result stresses important limitations in using SDMs for broad scale spatial studies, based on limited, spatially aggregated data, and low-resolution descriptors. |
|
| |
Programme |
1044,1124 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
Bachelor's 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 |
8184 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
|
|
| |
Title |
The high diversity of Southern Ocean sea stars (Asteroidea) reveals original evolutionary pathways |
Type |
Journal |
| |
Year |
2021 |
Publication |
Progress in oceanography |
Abbreviated Journal |
|
|
| |
Volume |
190 |
Issue |
|
Pages |
102472 |
|
| |
Keywords |
Antarctica Biodiversity COI mtDNA Echinodermata Evolution Phylogeography |
|
| |
Abstract |
Benthic life in the Southern Ocean (SO) features unique life history traits and species assemblages, but the origin and evolution of many of these taxonomic groups is still unclear. Sea stars (Asteroidea) are a diversified and abundant component of benthic ecosystems in the SO, in which they can play key ecological roles. Former studies suggest that the diversity of the entire class is still poorly known and underestimated, hampering the assessment of the origin and evolution of the class in the SO. In the present study, we analyse spatial patterns of SO sea star diversity using an occurrence database of ~14,000 entries. The biogeographic analysis is coupled with the exploration of an extensive molecular phylogeny based on over 4,400 specimen sequences to inform, support and/or question the observed diversity patterns. We show that the current taxonomy of SO asteroids needs revision and that their diversity has generally been overlooked and misinterpreted. Molecular results highlight the recent diversification of most studied taxa, at genus and species levels, which supports an evolutionary scenario referring to successive invasion and exchange events between the SO and adjacent regions, and clade diversification during periods of rapid environmental changes driven by the succession of glacial cycles. Our work advocates for employing, and endorsing the use of extensive genetic barcode libraries for biodiversity studies. |
|
| |
Programme |
1044,1124 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
Bachelor's thesis |
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0079-6611 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8183 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Laine Chanteloup, Fabienne Joliet, Thora M. Herrmann |
|
| |
Title |
Learning and insights from a participatory photography project with Cree and Inuit about the land (Nunavik, Canada) |
Type |
Journal |
| |
Year |
2019 |
Publication |
Polar Geography |
Abbreviated Journal |
|
|
| |
Volume |
42 |
Issue |
2 |
Pages |
125-143 |
|
| |
Keywords |
Canada indigenous Peoples Interculturality Nunavik Participatory methods and design participatory photography |
|
| |
Abstract |
|
|
| |
Programme |
1043 |
|
| |
Campaign |
|
|
| |
Address |
|
|
| |
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 |
1088-937X |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
yes |
|
| |
Call Number |
|
Serial |
8182 |
|
| Permanent link to this record |
