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Author | R. Traversi, S. Becagli, M. Brogioni, L. Caiazzo, V. Ciardini, F. Giardi, M. Legrand, G. Macelloni, B. Petkov, S. Preunkert, C. Scarchilli, M. Severi, V. Vitale, R. Udisti | |||||
Title | Multi-year record of atmospheric and snow surface nitrate in the central Antarctic plateau | Type | Journal | |||
Year | 2017 | Publication | Chemosphere | Abbreviated Journal ![]() |
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Volume | 172 | Issue | Pages | 341-354 | ||
Keywords | Aerosol Antarctica Dome C Nitrate Stratosphere-troposphere exchange Surface snow | |||||
Abstract | Continuous all year-round samplings of atmospheric aerosol and surface snow at high (daily to 4-day) resolution were carried out at Dome C since 2004-05 to 2013 and nitrate records are here presented. Basing on a larger statistical data set than previous studies, results confirm that nitrate seasonal pattern is characterized by maxima during austral summer for both aerosol and surface snow, occurring in-phase with solar UV irradiance. This temporal pattern is likely due to a combination of nitrate sources and post-depositional processes whose intensity usually enhances during the summer. Moreover, it should be noted that a case study of the synoptic conditions, which took place during a major nitrate event, showed the occurrence of a stratosphere-troposphere exchange. The sampling of both matrices at the same time with high resolution allowed the detection of a an about one-month long recurring lag of summer maxima in snow with respect to aerosol. This result can be explained by deposition and post-deposition processes occurring at the atmosphere-snow interface, such as a net uptake of gaseous nitric acid and a replenishment of the uppermost surface layers driven by a larger temperature gradient in summer. This hypothesis was preliminarily tested by a comparison with surface layers temperature data in the 2012-13 period. The analysis of the relationship between the nitrate concentration in the gas phase and total nitrate obtained at Dome C (2012-13) showed the major role of gaseous HNO3 to the total nitrate budget suggesting the need to further investigate the gas-to-particle conversion processes. | |||||
Programme | 414 | |||||
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ISSN | 0045-6535 | ISBN | 0045-6535 | Medium | ||
Area | Expedition | Conference | ||||
Notes | Approved | yes | ||||
Call Number | Serial | 6671 | ||||
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Author | J. Grazioli, C. Genthon, B. Boudevillain, C. Duran-Alarcon, M. Del Guasta, J.-B. Madeleine, A. Berne | |||||
Title | Measurements of precipitation in Dumont d'Urville, Adélie Land, East Antarctica | Type | Journal | |||
Year | 2017 | Publication | The Cryosphere | Abbreviated Journal ![]() |
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Volume | 11 | Issue | 4 | Pages | 1797-1811 | |
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Abstract | The first results of a campaign of intensive observation of precipitation in Dumont d'Urville, Antarctica, are presented. Several instruments collected data from November 2015 to February 2016 or longer, including a polarimetric radar (MXPol), a Micro Rain Radar (MRR), a weighing gauge (Pluvio2), and a Multi-Angle Snowflake Camera (MASC). These instruments collected the first ground-based measurements of precipitation in the region of Adélie Land (Terre Adélie), including precipitation microphysics. Microphysical observations during the austral summer 2015/2016 showed that, close to the ground level, aggregates are the dominant hydrometeor type, together with small ice particles (mostly originating from blowing snow), and that riming is a recurring process. Eleven percent of the measured particles were fully developed graupel, and aggregates had a mean riming degree of about 30 %. Spurious precipitation in the Pluvio2 measurements in windy conditions, leading to phantom accumulations, is observed and partly removed through synergistic use of MRR data. The yearly accumulated precipitation of snow (300 m above ground), obtained by means of a local conversion relation of MRR data, trained on the Pluvio2 measurement of the summer period, is estimated to be 815 mm of water equivalent, with a confidence interval ranging between 739.5 and 989 mm. Data obtained in previous research from satellite-borne radars, and the ERA-Interim reanalysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) provide lower yearly totals: 655 mm for ERA-Interim and 679 mm for the climatological data over DDU. ERA-Interim overestimates the occurrence of low-intensity precipitation events especially in summer, but it compensates for them by underestimating the snowfall amounts carried by the most intense events. Overall, this paper provides insightful examples of the added values of precipitation monitoring in Antarctica with a synergistic use of in situ and remote sensing measurements. | |||||
Programme | 1143 | |||||
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ISSN | 1994-0424 | ISBN | 1994-0424 | Medium | ||
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Notes | Approved | yes | ||||
Call Number | Serial | 6673 | ||||
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Author | Cyril Palerme, Christophe Genthon, Chantal Claud, Jennifer E. Kay, Norman B. Wood, Tristan L’Ecuyer | |||||
Title | Evaluation of current and projected Antarctic precipitation in CMIP5 models | Type | Journal | |||
Year | 2017 | Publication | Climate Dynamics | Abbreviated Journal ![]() |
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Volume | 48 | Issue | 1-2 | Pages | 225-239 | |
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Abstract | On average, the models in the Fifth Climate Model Intercomparison Project archive predict an increase in Antarctic precipitation from 5.5 to 24.5 % between 1986–2005 and 2080–2099, depending on greenhouse gas emissions scenarios. This translates into a moderation of future sea level rise ranging from −19 to −71 mm between 2006 and 2099. However, comparison with CloudSat and ERA-Interim data show that almost all the models overestimate current Antarctic precipitation, some by more than 100 %. If only the models that agree with CloudSat data within 20 % of error are considered, larger precipitation changes (from 7.4 to 29.3 %) and impact on sea level (from −25 to −85 mm) are predicted. A common practice of averaging all models to evaluate climate projections thus leads to a significant underestimation of the contribution of Antarctic precipitation to future sea level. Models simulate, on average, a 7.4 %/°C precipitation change with surface temperature warming. The models in better agreement with CloudSat observations for Antarctic snowfall predict, on average, larger temperature and Antarctic sea ice cover changes, which could explain the larger changes in Antarctic precipitation simulated by these models. The agreement between the models, CloudSat data and ERA-Interim is generally less in the interior of Antarctica than at the peripheries, but the interior is also where climate change will induce the smallest absolute change in precipitation. About three-quarters of the impact on sea level will result from precipitation change over the half most peripheral and lowest elevation part of the surface of Antarctica. | |||||
Programme | 1143 | |||||
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ISSN | 0930-7575, 1432-0894 | ISBN | 0930-7575, 1432-0894 | Medium | ||
Area | Expedition | Conference | ||||
Notes | Approved | yes | ||||
Call Number | Serial | 6674 | ||||
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Author | Madeleine J.-b., C. Genthon, E. Vignon, F. Hourdin, F. Lemonnier, H. Gallée, And L. Piard | |||||
Title | Measuring and Modeling Ice Supersaturation at Dome C | Type | Communication | |||
Year | 2017 | Publication | 12th workshop on antarctic meteorlogy and climate, boulder, co, usa, 28-29 juin 2017 | Abbreviated Journal ![]() |
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Programme | 1013 | |||||
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Notes | Approved | yes | ||||
Call Number | Serial | 6678 | ||||
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Author | Merkling Thomas, Blanchard Pierrick, Chastel Olivier, Glauser Gaëtan, Vallat‐Michel Armelle, Hatch Scott A., Danchin Etienne, Helfenstein Fabrice, Isaksson Caroline | |||||
Title | Reproductive effort and oxidative stress: effects of offspring sex and number on the physiological state of a long‐lived bird | Type | Journal | |||
Year | 2017 | Publication | Functional Ecology | Abbreviated Journal ![]() |
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Volume | 31 | Issue | 6 | Pages | 1201-1209 | |
Keywords | black‐legged kittiwake cost of reproduction hypothesis malondialdehydes oxidative cost of reproduction parental care Rissa tridactyla: superoxide dismutase sex allocation | |||||
Abstract | Summary Individuals must trade?off between energetically costly activities to maximize their fitness. However, the underlying physiological mechanism remains elusive. Oxidative stress, the imbalance between reactive oxygen species production and antioxidant and/or repair activities, has been suggested to underlie life?history trade?offs: greater investment in reproduction supposedly generating higher oxidative damage, thus reducing life span. While most studies used natural or experimental variation in offspring number to examine how reproduction affects oxidative stress, none studied the impact of offspring sex, although it could influence physiological costs and fitness, if the sexes differ in terms of energetic cost. Here, we aim at further understanding how reproduction (in terms of offspring sex, experimentally manipulated and number, not manipulated) influences oxidative stress in a wild seabird, where sons are energetically costlier than daughters. We did so by conducting a chick fostering experiment (to disentangle foster and produced sex ratio) and using four oxidative stress markers plus baseline corticosterone. First, the results suggest that individual physiological state before laying modulates upcoming reproductive effort. Individuals with higher pre?laying baseline corticosterone and lower antioxidant activity, estimated by their superoxide dismutase activity, subsequently invested more in reproduction, estimated by the cumulative number of days spent rearing chicks. Hence, it seems that only individuals that could afford to invest heavily in reproduction did so. Then, we examined the effects of reproductive effort on individual physiological state at the end of the breeding season. Higher reproductive effort seemed to imply higher physiological costs. Oxidative stress, estimated by the ratio of oxidized over reduced glutathione, increased with more male?biased foster sex ratio among mothers but not among fathers, whereas baseline corticosterone did so in both sexes. Similarly, lipid oxidative damage to red blood cells increased with increasing cumulative number of days spent rearing chicks. Our study provides the first evidence that brood sex ratio variation can affect oxidative balance, potentially in a sex?specific way, although more studies are needed to understand whether the observed physiological costs could lead to fitness costs. It also highlights the need to consider sex ratio in future studies investigating the role of oxidative stress in life?history trade?offs. A lay summary is available for this article. | |||||
Programme | 1162 | |||||
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ISSN | 0269-8463 | ISBN | 0269-8463 | Medium | ||
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Notes | Approved | yes | ||||
Call Number | Serial | 6679 | ||||
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Author | Young Rebecca C., Welcker Jorg, Barger Christopher P., Hatch Scott A., Merkling Thomas, Kitaiskaia Evgenia V., Haussmann Mark F., Kitaysky Alexander S. | |||||
Title | Effects of developmental conditions on growth, stress and telomeres in black‐legged kittiwake chicks | Type | Journal | |||
Year | 2017 | Publication | Molecular Ecology | Abbreviated Journal ![]() |
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Volume | 26 | Issue | 13 | Pages | 3572-3584 | |
Keywords | antioxidant corticosterone early‐life conditions growth rate telomeres thrifty phenotype | |||||
Abstract | Early‐life conditions can drive ageing patterns and life history strategies throughout the lifespan. Certain social, genetic and nutritional developmental conditions are more likely to produce high‐quality offspring: those with good likelihood of recruitment and productivity. Here, we call such conditions “favoured states” and explore their relationship with physiological variables during development in a long‐lived seabird, the black‐legged kittiwake (Rissa tridactyla). Two favoured states were experimentally generated by manipulation of food availability and brood size, while hatching order and sex were also explored as naturally generating favoured states. Thus, the favoured states we explored were high food availability, lower levels of sibling competition, hatching first and male sex. We tested the effects of favoured developmental conditions on growth, stress, telomere length (a molecular marker associated with lifespan) and nestling survival. Generation of favoured states through manipulation of both the nutritional and social environments furthered our understanding of their relative contributions to development and phenotype: increased food availability led to larger body size, reduced stress and higher antioxidant status, while lower sibling competition (social environment) led to lower telomere loss and longer telomere lengths in fledglings. Telomere length predicted nestling survival, and wing growth was also positively correlated with telomere length, supporting the idea that telomeres may indicate individual quality, mediated by favoured states. | |||||
Programme | 1162 | |||||
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ISSN | 0962-1083 | ISBN | 0962-1083 | Medium | ||
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Notes | Approved | yes | ||||
Call Number | Serial | 6680 | ||||
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Author | Charlène Guillaumot | |||||
Title | 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. | Type | Master 2 | |||
Year | 2016 | Publication | Abbreviated Journal ![]() |
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Abstract | Species and community distribution modeling is commonly used in ecology, biogeography and can constitute seminal conservation planning tools. However, available data, often compiled from ancient different campaigns, are restricted. This is a common case in low-access and little-investigated areas such as the Southern Ocean. Spatial (areas, strategies, sampling tools) and temporal heterogeneities (environmental changes over the sampling period) are present and influence the performance of modeling tools. Our work aims at testing the performance of widely used procedures (MaxEnt, BRT) to model the current distribution of four echinoid species with contrasted ecological niches over the Kerguelen plateau. Presence-only data were used. They were compiled from different campaigns (1872-2015) and might show significant heterogeneities. Model performance was first tested while comparing subsets with different occurrence numbers and spatial clustering. The influence of known environmental changes and projection quality were compared for the two algorithms. Accounting for these results, potential shifts in species distributions were modeled in accordance with the IPCC A1B scenarii (Intergovernmental Panel on Climate Change) for 2100 and 2200 and were compared to the magnitude of past changes (1955-2012). |
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Programme | 1044 | |||||
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Notes | Approved | yes | ||||
Call Number | Serial | 6681 | ||||
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Author | Emmanuelle Trouslard | |||||
Title | Ecorégionalisation et caractérisation des enjeux de conservation des habitats benthiques marins du plateau de Kerguelen | Type | Master 2 | |||
Year | 2017 | Publication | Abbreviated Journal ![]() |
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Programme | 1044 | |||||
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Notes | Approved | yes | ||||
Call Number | Serial | 6682 | ||||
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Author | Alexis Bazin | |||||
Title | Intérêt de l’étude des signatures isotopiques δ13C et δ15N pour la caractérisation de la sensibilité d’espèces confrontées aux changements environnementaux | Type | Master 2 | |||
Year | 2016 | Publication | Abbreviated Journal ![]() |
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Abstract | Natural environments are increasingly affected by human activities since the early twentieth century. Both Polar Regions are particularly affected by those climate changes. The Southern Ocean plays a key role in global ocean circulation and global climate. It participated in the thermohaline circulation, which regulates the global climate. Marine environments in Kerguelen Islands were relatively little affected by human activities. The isotopic signatures δ13C δ15N of three species of sea urchins harvested in different environments, were analyzed to characterize their food strategies. A mapping of the trophic niche each species was performed by using the SIBER mixing model. This aim to study the trophic plasticity of these organisations and the possible interactions between them. The results show that there is no interaction between species due to their very different diets. However inter-area and inter-species differences have been identified. The isotopic values δ13C and δ15N will be sensitive to the physico-chemical conditions of the environment. A second mixture model is used, SIAR, to characterize the diet of S.diadema at Port Matha (-2m), but also C.nutrix and S.diadema of Ilot des Trois Bergers (-20m). The C.nutrix will favor sponges, S.diadema feed from different sources (sponges, algae, sediment). |
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Programme | 1044 | |||||
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Notes | Approved | yes | ||||
Call Number | Serial | 6683 | ||||
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Author | Marie Cabessut | |||||
Title | Etude des réseaux trophiques dans les environnements côtiers des Iles Kerguelen : analyse des régimes alimentaires d'espèces d'oursins et de leur plasticité trophique à l'aide de traceurs isotopiques (δ13C, δ15N, δ34S). | Type | Master 1 | |||
Year | 2017 | Publication | Abbreviated Journal ![]() |
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Abstract | Few studies have been interested on environmental changes in Austral Ocean. The Kerguelen Islands important for marine currents are interesting for assessing these impacts on marine biodiversity. Ctenocidaris nutrix is an urchin providing micro-habitats for some organisms from his environment. Two populations of urchins were sampled at two different sites, Ile Haute and Ile Suhm, with the aim of analyzing if the two populations belong to the same species. Stable isotopic ratios (δ13C, δ15N) provide a representation of trophic niche of the two populations of C.nutrix. The isotopic mixing model (SIAR) characterizes the plasticity, position of organisms within the trophic network and their diet. The two populations have distinct trophic niches, supported by morphological and isotopic divergences and varied diets. Gut contents were analyzed and supports variations in urchin diet. Genetic analyzes are planned to confirm phenotypic and trophic differences between the two populations and it would permit to conclude whether the two populations belong to the same species. |
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Programme | 1044 | |||||
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Notes | Approved | yes | ||||
Call Number | Serial | 6684 | ||||
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