González-Wevar C.A., Hüne M., Segovia N.I., Nakano T., Spencer H., Chown S.L., Saucède T.; Johnstone G., Mansilla A. & E. Poulin. (2016). Following the Antarctic Circumpolar Current: Patterns and processes in the biogeography of the limpet Nacella (Mollusca: Patellogastropoda) across the Southern Ocean. J. Biogeogr., .
Abstract: Aim We use an integrative biogeographical approach to further understand the evolution of an important Southern Ocean marine benthic element, the limpet genus Nacella (Mollusca: Patellogastropoda). Location Southern Ocean. Methods We used multi-locus time-calibrated phylogeny of Nacella at the scale of the whole Southern Ocean to elucidate the underlying processes involved in the origin and diversification of the genus. Results Divergence-time estimates suggest that soon after its origin during the mid-Miocene (c. 12.5 Ma), Nacella separated into two main lineages currently distributed in (1) South America and (2) Antarctica and the sub-Antarctic islands. We identified two pulses of diversification, during the late Miocene (8 to 5.5 Ma) and the Pleistocene (< 1 Ma). Main conclusions Major periods of climatic and oceanographical change strongly affected the biogeography of Nacella and demonstrate both the long- and short-term influence of the Antarctic Circumpolar Current across the Southern Ocean. Our analyses support the validity of all currently recognized Nacella species and reveal a new South-American lineage. This work constitutes the most detailed molecular-based study of an ecologically important, near-shore invertebrate Southern Ocean group and in so doing contributes to the improved understanding of the underlying patterns and processes in the origin and diversification of marine benthic fauna across this globally important region.
Programme: 1044
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Solomina, O., Bradley., R.S., Jomelli, V., Geirsdottir, A., Kaufman, D., Koch, J., Masiokas, M., Miller, G., Nesje, A., Nicolussi, K., Owen, L., Wanner, H., Wiles, G., Yang, B. (2016). Glacier fluctuations in the last 2000 years. . QUATERNARY SCIENCE REVIEWS, 149(13), 61–90.
Abstract: A global compilation of glacier advances and retreats for the past two millennia grouped by 17 regions (excluding Antarctica) highlights the nature of glacier fluctuations during the late Holocene. The dataset includes 275 time series of glacier fluctuations based on historical, tree ring, lake sediment, radiocarbon and terrestrial cosmogenic nuclide data. The most detailed and reliable series for individual glaciers and regional compilations are compared with summer temperature and, when available, winter precipitation reconstructions, the most important parameters for glacier mass balance. In many cases major glacier advances correlate with multi-decadal periods of decreased summer temperature. In a few cases, such as in Arctic Alaska and western Canada, some glacier advances occurred during relatively warm wet times. The timing and scale of glacier fluctuations over the past two millennia varies greatly from region to region. However, the number of glacier advances shows a clear pattern for the high, mid and low latitudes and, hence, points to common forcing factors acting at the global scale. Globally, during the first millennium CE glaciers were smaller than between the advances in 13th to early 20th centuries CE. The precise extent of glacier retreat in the first millennium is not well defined; however, the most conservative estimates indicate that during the 1st and 2nd centuries in some regions glaciers were smaller than at the end of 20th/early 21st centuries. Other periods of glacier retreat are identified regionally during the 5th and 8th centuries in the European Alps, in the 3rd–6th and 9th centuries in Norway, during the 10th–13th centuries in southern Alaska, and in the 18th century in Spitsbergen. However, no single period of common global glacier retreat of centennial duration, except for the past century, has yet been identified. In contrast, the view that the Little Ice Age was a period of global glacier expansion beginning in the 13th century (or earlier) and reaching a maximum in 17th–19th centuries is supported by our data. The pattern of glacier variations in the past two millennia corresponds with cooling in reconstructed temperature records at the continental and hemispheric scales. The number of glacier advances also broadly matches periods showing high volcanic activity and low solar irradiance over the past two millennia, although the resolution of most glacier chronologies is not enough for robust statistical correlations. Glacier retreat in the past 100–150 years corresponds to the anthropogenic global temperature increase. Many questions concerning the relative strength of forcing factors that drove glacier variations in the past 2 ka still remain.
Programme: 1048
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Bourriquen M., Baltzer A., Mercier D., Fournier J., Pérez L., Haquin S., Bernard E., Jensen M., . (2016). Delta progradation and offshore sedimentary lobes in the northern coast of the Brøgger Peninsula (Spitsberg, Svalbard).
Abstract: presented during the 11th International Conference on Permafrost (ICOP 2016) », Potsdam, 2016, June, 20-24.
Programme: 1172
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Poirson M. (2016). Étude des habitats côtiers rocheux des îles Kerguelen et bilan des connaissances dans le but de mettre en place un suivi à long terme des communautés benthiques. Master 1.
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Bazin A. (2016). Intérêt de l’étude des signatures isotopiques δ13C et δ15N pour la caractérisation de la sensibilité d’espèces marines confrontées aux changements environnementaux. Master 2.
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Guillaumot c. (2016). Hétérogénéités spatiales, temporelles et efforts d'échantillonnage: influence sur la modélisation de distribution d'espèces. Le cas d'étude des échinides du plateau des Kerguelen. Master 2..
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Charlène Guillaumot, Alexis Martin, Marc Eléaume, Thomas Saucède. (2016). Temporal, spatial, and sampling heterogeneities in species distribution modeling. The case study of the data-poor area of the Kerguelen Plateau. 34th SCAR Open Science Conference and Biennal Meetings, 19-31 août 2016, Kuala Lumpur, Malaysia..
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V. Masson-Delmotte. (2016). Svalbard isotopic measurements.
Abstract: French-Swedish partnership, GIWA project
Programme: 1134
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Steen-Larsen, H.C., Risi, C., Masson-Delmotte, V., Werner, M., Yoshimura, K. (2016). Evaluating the skills of isotope-enabled general circulation models against in situ atmospheric water vapor isotope observations. J. Geophys. Res., 122(1), 2016JD025443.
Abstract: The skills of isotope-enabled general circulation models are evaluated against atmospheric water vapor isotopes. We have combined in situ observations of surface water vapor isotopes spanning multiple field seasons (2010, 2011, and 2012) from the top of the Greenland Ice Sheet (NEEM site: 77.45°N, 51.05°W, 2484 m above sea level) with observations from the marine boundary layer of the North Atlantic and Arctic Ocean (Bermuda Islands 32.26°N, 64.88°W, year: 2012; south coast of Iceland 63.83°N, 21.47°W, year: 2012; South Greenland 61.21°N, 47.17°W, year: 2012; Svalbard 78.92°N, 11.92°E, year: 2014). This allows us to benchmark the ability to simulate the daily water vapor isotope variations from five different simulations using isotope-enabled general circulation models. Our model-data comparison documents clear isotope biases both on top of the Greenland Ice Sheet (1–11‰ for δ18O and 4–19‰ for d-excess depending on model and season) and in the marine boundary layer (maximum differences for the following: Bermuda δ18O = ~1‰, d-excess = ~3‰; South coast of Iceland δ18O = ~2‰, d-excess = ~ 5‰; South Greenland δ18O = ~4‰, d-excess = ~7‰; Svalbard δ18O = ~2‰, d-excess = ~7‰). We find that the simulated isotope biases are not just explained by simulated biases in temperature and humidity. Instead, we argue that these isotope biases are related to a poor simulation of the spatial structure of the marine boundary layer water vapor isotopic composition. Furthermore, we specifically show that the marine boundary layer water vapor isotopes of the Baffin Bay region show strong influence on the water vapor isotopes at the NEEM deep ice core-drilling site in northwest Greenland. Our evaluation of the simulations using isotope-enabled general circulation models also documents wide intermodel spatial variability in the Arctic. This stresses the importance of a coordinated water vapor isotope-monitoring network in order to discriminate amongst these model behaviors.
Programme: 1134
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Angot, H., Magand, O., Helmig, D., Ricaud, P., Quennehen, B., Gallée, H., Del Guasta, M., Sprovieri, F., Pirrone, N., Savarino, J., and Dommergue, A. (2016). New insights into the atmospheric mercury cycling in central Antarctica and implications on a continental scale. ATMOSPHERIC CHEMISTRY AND PHYSICS, 16(13), 8249–8264.
Abstract: Under the framework of the GMOS project (Global Mercury Observation System) atmospheric mercury monitoring has been implemented at Concordia Station on the high-altitude Antarctic plateau (75°06′?S, 123°20′?E, 3220?m above sea level). We report here the first year-round measurements of gaseous elemental mercury (Hg(0)) in the atmosphere and in snowpack interstitial air on the East Antarctic ice sheet. This unique data set shows evidence of an intense oxidation of atmospheric Hg(0) in summer (24-hour daylight) due to the high oxidative capacity of the Antarctic plateau atmosphere in this period of the year. Summertime Hg(0) concentrations exhibited a pronounced daily cycle in ambient air with maximal concentrations around midday. Photochemical reactions and chemical exchange at the air–snow interface were prominent, highlighting the role of the snowpack on the atmospheric mercury cycle. Our observations reveal a 20 to 30?% decrease of atmospheric Hg(0) concentrations from May to mid-August (winter, 24?h darkness). This phenomenon has not been reported elsewhere and possibly results from the dry deposition of Hg(0) onto the snowpack. We also reveal the occurrence of multi-day to weeklong atmospheric Hg(0) depletion events in summer, not associated with depletions of ozone, and likely due to a stagnation of air masses above the plateau triggering an accumulation of oxidants within the shallow boundary layer. Our observations suggest that the inland atmospheric reservoir is depleted in Hg(0) in summer. Due to katabatic winds flowing out from the Antarctic plateau down the steep vertical drops along the coast and according to observations at coastal Antarctic stations, the striking reactivity observed on the plateau most likely influences the cycle of atmospheric mercury on a continental scale.
Programme: 910
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