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Cyril Dégletagne, Damien Roussel, Jean Louis Rouanet, Fanny Baudimont, Elodie-Marie Moureaux, Steve Harvey, Claude Duchamp, Yvon Le Maho, Mireille Raccurt. (2013). Growth Prior to Thermogenesis for a Quick Fledging of Adélie Penguin Chicks (Pygoscelis adeliae) (Vol. 8).
Abstract: The evolutionary trade-off between tissue growth and mature function restricts the post natal development of polar birds. The present study uses an original integrative approach as it includes gene expression, plus biochemical and physiological analysis to investigate how Adélie penguin chicks achieve a rapid growth despite the energetic constraints linked to the cold and the very short breeding season in Antarctica. In pectoralis muscle, the main thermogenic tissue in birds, our data show that the transition from ectothermy to endothermy on Day 15 post- hatching is associated with substantial and coordinated changes in the transcription of key genes. While the early activation of genes controlling cell growth and differentiation (avGHR, avIGF-1R, T3Rβ) is rapidly down-regulated after hatching, the global increase in the relative expression of genes involved in thermoregulation (avUCP, avANT, avLPL) and transcriptional regulation (avPGC1α, avT3Rβ) underlie the muscular acquisition of oxidative metabolism. Adélie chicks only become real endotherms at 15 days of age with the development of an oxidative muscle phenotype and the ability to shiver efficiently. The persistent muscular expression of IGF-1 throughout growth probably acts as a local mediator to adjust muscle size and its oxidative capacity to anticipate the new physiological demands of future Dives in cold water. The up-regulation of T3Rβ mRNA levels suggests that circulating T3 may play an important role in the late maturation of skeletal muscle by reinforcing, at least in part, the paracrine action of IGF-1. From day 30, the metabolic shift from mixed substrate to lipid metabolism, with the markedly increased mRNA levels of muscle avLPL, avANT and avUCP, suggests the late development of a fatty acid-enhanced muscle non-shivering thermogenesis mechanism. This molecular control is the key to this finely-tuned strategy by which the Adélie penguin chick successfully heads for the sea on schedule.
Keywords: Birds Body temperature Gene expression Mitochondria Muscle biochemistry Penguins Skeletal muscles Thermogenesis
Programme: 131
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Françoise Amélineau, David Grémillet, Delphine Bonnet, Tangi Le Bot, Jérôme Fort. (2016). Where to Forage in the Absence of Sea Ice? Bathymetry As a Key Factor for an Arctic Seabird (Vol. 11).
Abstract: The earth is warming at an alarming rate, especially in the Arctic, where a marked decline in sea ice cover may have far-ranging consequences for endemic species. Little auks, endemic Arctic seabirds, are key bioindicators as they forage in the marginal ice zone and feed preferentially on lipid-rich Arctic copepods and ice-associated amphipods sensitive to the consequences of global warming. We tested how little auks cope with an ice-free foraging environment during the breeding season. To this end, we took advantage of natural variation in sea ice concentration along the east coast of Greenland. We compared foraging and diving behaviour, chick diet and growth and adult body condition between two years, in the presence versus nearby absence of sea ice in the vicinity of their breeding site. Moreover, we sampled zooplankton at sea when sea ice was absent to evaluate prey location and little auk dietary preferences. Little auks foraged in the same areas both years, irrespective of sea ice presence/concentration, and targeted the shelf break and the continental shelf. We confirmed that breeding little auks showed a clear preference for larger copepod species to feed their chick, but caught smaller copepods and nearly no ice-associated amphipod when sea ice was absent. Nevertheless, these dietary changes had no impact on chick growth and adult body condition. Our findings demonstrate the importance of bathymetry for profitable little auk foraging, whatever the sea-ice conditions. Our investigations, along with recent studies, also confirm more flexibility than previously predicted for this key species in a warming Arctic.
Keywords: Birds Copepods Foraging Oceans Predation Sea ice Seabirds Zooplankton
Programme: 388
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Aline Peltier, Arnaud Chulliat. (2010). On the feasibility of promptly producing quasi-definitive magnetic observatory data (Vol. 62).
Abstract: Magnetic observatories currently distribute two types of data: preliminary data, available in less than 72 hrs in the case of INTERMAGNET observatories, and definitive baseline-corrected data, produced only once a year. Several users and groups of users have expressed the need for baseline-corrected observatory data produced in a continuous manner. The main applications for such quasi-definitive data include geomagnetic field modeling and the calculation of geomagnetic activity indices. We present an original method for producing quasi-definitive data at the end of each calendar month using temporary baselines. Preliminary and definitive data at nine INTERMAGNET observatories are used to test this method, simulating the production of quasi-definitive data throughout the year 2008. The temporary baselines obtained are very close to the definitive ones, except during the last few days of each time interval. The means and standard deviations of the differences between quasi-definitive and definitive data do not exceed 0.3 nT, well below the current INTERMAGNET standard of accuracy. This result demonstrates the feasibility of promptly producing quasi-definitive data at most magnetic observatories of INTERMAGNET type.
Keywords: baseline data processing geomagnetic modeling Magnetic observatory quasi-definitive data
Programme: 139
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Maria V. Murgia, Lesley Bell-Sakyi, José de la Fuente, Timothy J. Kurtti, Benjamin L. Makepeace, Ben Mans, Karen D. McCoy, Ulrike Munderloh, Olivier Plantard, Claude Rispe, Manuel Rodriguez Valle, Ala Tabor, Saravanan Thangamani, Jyothi Thimmapuram, Catherine A. Hill. (2019). Meeting the challenge of tick-borne disease control: A proposal for 1000 Ixodes genomes (Vol. 10).
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J. Gutt, E. Isla, A. N. Bertler, G. E. Bodeker, T. J. Bracegirdle, R. D. Cavanagh, J. C. Comiso, P. Convey, V. Cummings, R. De Conto, D. De Master, G. di Prisco, F. d'Ovidio, H. J. Griffiths, A. L. Khan, J. López-Martínez, A. E. Murray, U. N. Nielsen, S. Ott, A. Post, Y. Ropert-Coudert, T. Saucède, R. Scherer, S. Schiaparelli, I. R. Schloss, C. R. Smith, J. Stefels, C. Stevens, J. M. Strugnell, S. Trimborn, C. Verde, E. Verleyen, D. H. Wall, N. G. Wilson, J. C. Xavier. (2018). Cross-disciplinarity in the advance of Antarctic ecosystem research (Vol. 37).
Abstract: The biodiversity, ecosystem services and climate variability of the Antarctic continent and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disciplinary studies are especially important in Antarctic research. The conceptual study presented here is based on a workshop initiated by the Research Programme Antarctic Thresholds – Ecosystem Resilience and Adaptation of the Scientific Committee on Antarctic Research, which focussed on challenges in identifying and applying cross-disciplinary approaches in the Antarctic. Novel ideas and first steps in their implementation were clustered into eight themes. These ranged from scale problems, through risk maps, and organism/ecosystem responses to multiple environmental changes and evolutionary processes. Scaling models and data across different spatial and temporal scales were identified as an overarching challenge. Approaches to bridge gaps in Antarctic research programmes included multi-disciplinary monitoring, linking biomolecular findings and simulated physical environments, as well as integrative ecological modelling. The results of advanced cross-disciplinary approaches can contribute significantly to our knowledge of Antarctic and global ecosystem functioning, the consequences of climate change, and to global assessments that ultimately benefit humankind.
Keywords: Multiple stressors Response to environmental changes Risk maps Scaling Sea-ice Southern Ocean
Programme: 1091
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Kélig Mahé, Romain Elleboode, Christophe Loots, Philippe Koubbi. (2016). Growth of an Inshore Antarctic fish, Trematomus newnesi (Nototheniidae), off Adelie Land (Vol. 10).
Abstract: Dusky rockcod, Trematomus newnesi, is a widely distributed neritic circumpolar Antarctic fish species. We conducted a study on age and growth of T. newnesi in coastal waters of Adélie Land in East Antarctica. A total of 289 specimens were collected in 2003, 2005, 2006 and 2009. They consisted of 122 females, 132 males and 35 immature specimens. Total length (TL) and total weight (W) of these fish ranged from 13.5 to 25 cm and 19.7–174 g respectively for females and from 12 to 20.9 cm and from 24.1 to 144.1 g for males. The TL/W relationship was described by the following parameters: a = 7.2.10−3 and b = 3.127, showing no significant difference between sex (ANCOVA, P < 0.05). Fish age was estimated by counting annual growth increments on polished transverse sections of sagittal otoliths. Age estimates varied from 3 to 14 years. There was a significant relationship between otolith morphological features (weight and radius) and age with no difference between males and females (p > 0.05). The estimated values of Von Bertalanffy growth curve L∞ (cm), W∞ (g) and k were 26.6, 200.6 and 0.13 for females and 24.5, 147.0 and 0.15 for males respectively. The indices of growth performance between sexes were not significant. However, potential difference in growth rate between the morphs cannot be neglected.
Keywords: Adélie land Age Antarctic fish Growth Otoliths Trematomus newnesi
Programme: 1142
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A. Saintenoy, J.-M. Friedt, A. D. Booth, F. Tolle, E. Bernard, D. Laffly, C. Marlin, M. Griselin. (2012). Deriving ice thickness, glacier volume and bedrock morphology of Austre Lovénbreen (Svalbard) using GPR (Vol. 11).
Abstract: Austre Lovénbreen is a 4.6 km2 glacier on the Archipelago of Svalbard (79o N) that has been surveyed over the last 47 years in order to monitor in particular the glacier evolution and associated hydrological phenomena in the context of nowadays global warming. A three-week field survey during April 2010 allowed for the acquisition of a dense mesh of ground-penetrating radar (GPR) data with an average of 14 683 points per km2 (67 542 points total) on the glacier surface. The profiles were acquired using Malå equipment with 100 MHz antennas, towed slowly enough to record on average every 0.3 m, a trace long enough to sound down to 189 m of ice. One profile was repeated with a 50 MHz antenna set to improve electromagnetic wave propagation depth in scattering media observed in the cirques closest to the slopes. The GPR was coupled to a GPS system to position traces. Each profile was manually edited using standard GPR data processing including migration, to pick the reflection arrival time from the ice-bedrock interface. Snow cover was evaluated through 42 snow drilling measurements regularly spaced to cover the entire glacier. These data were acquired at the time of the GPR survey and subsequently spatially interpolated using ordinary kriging. Using a snow velocity of 0.22 m/ns, the snow thickness was converted to electromagnetic wave traveltimes and subtracted from the picked traveltimes to the ice-bedrock interface. The resulting traveltimes were converted to ice thickness using a velocity of 0.17 m/ns. The velocity uncertainty is discussed from a common midpoint profile analysis. A total of 67 542 geo-referenced data points with GPR-derived ice thicknesses, in addition to a glacier boundary line derived from satellite images taken during summer, were interpolated over the entire glacier surface using kriging with a 10 m grid size. Some uncertainty analyses were carried out and we calculated an averaged ice thickness of 76 m and a maximum depth of 164 m with a relative error of 11.9%. The volume of the glacier is derived as 0.3487 ± 0.041 km3. Finally a 10 m grid map of the bedrock topography was derived by subtracting the ice thicknesses from a dual-frequency GPSderived digital elevation model of the surface. These two data sets are the first step for modelling thermal evolution of a glacier and its bedrock, as well as the main hydrological network.
Programme: 1108
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Vincent Zvénigorosky, Eric Crubézy, Morgane Gibert, Catherine Thèves, Clémence Hollard, Angéla Gonzalez, Sardana A. Fedorova, Anatoly N. Alexeev, Rozalia I. Bravina, Bertrand Ludes, Christine Keyser. (2016). The genetics of kinship in remote human groups (Vol. 25).
Abstract: For fifteen years, part of the work of our research team has been focused on the study of parental links between individuals living hundreds or thousands of years ago, whose remains have been found in single graves or large funerary complexes. These studies have been undertaken using methods developed by forensic genetics to identify individuals, mainly based on the genotyping of autosomal STR (Short Tandem Repeats). Issues arose from this work, namely the limits of studying small numbers of subjects, originating from groups of finite sizes where kinships cannot be inferred a priori and for which reference allelic frequencies do not exist. Although ideal human populations are rare when undertaking such studies, the Yakuts of Eastern Siberia constitute a very advantageous model, with large numbers of small pastoral communities and well-preserved archaeological material. The study of kinship in the ancient Yakuts allowed us to highlight the difficulties in analysing genetic data from small ancient human groups and to develop a strategy to improve the accuracy of statistical computations. This work describes this strategy and possible solutions to the study of populations outside of the frame of reference of global meta-populations, due either to isolation, remoteness or antiquity.
Keywords: Ancient DNA Genetic kinship Population genetics Short tandem repeats Yakutia
Programme: 1038
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A. El Yazidi, M. Ramonet, P. Ciais, G. Broquet, I. Pison, A. Abbaris, D. Brunner, S. Conil, M. Delmotte, F. Gheusi, F. Guerin, L. Hazan, N. Kachroudi, G. Kouvarakis, N. Mihalopoulos, L. Rivier, D. Serça. (2017). Identification of spikes associated with local sources in continuous time series of atmospheric CO, CO2 and CH4 (Vol. 11).
Abstract: This study deals with the problem of identifying atmospheric data influenced by local emissions that can result in spikes in time series of greenhouse gases and long-lived tracer measurements. We considered three spike detection methods known as coefficient of variation (COV), robust extraction of baseline signal (REBS) and standard deviation of the background (SD) to detect and filter positive spikes in continuous greenhouse gas time series from four monitoring stations representative of the European ICOS (Integrated Carbon Observation System) Research Infrastructure network. The results of the different methods are compared to each other and against a manual detection performed by station managers. Four stations were selected as test cases to apply the spike detection methods: a continental rural tower of 100 m height in eastern France (OPE), a high-mountain observatory in the south-west of France (PDM), a regional marine background site in Crete (FKL) and a marine clean-air background site in the Southern Hemisphere on Amsterdam Island (AMS). This selection allows us to address spike detection problems in time series with different variability. Two years of continuous measurements of CO2, CH4 and CO were analysed. All methods were found to be able to detect short-term spikes (lasting from a few seconds to a few minutes) in the time series. Analysis of the results of each method leads us to exclude the COV method due to the requirement to arbitrarily specify an a priori percentage of rejected data in the time series, which may over- or underestimate the actual number of spikes. The two other methods freely determine the number of spikes for a given set of parameters, and the values of these parameters were calibrated to provide the best match with spikes known to reflect local emissions episodes that are well documented by the station managers. More than 96 % of the spikes manually identified by station managers were successfully detected both in the SD and the REBS methods after the best adjustment of parameter values. At PDM, measurements made by two analyzers located 200 m from each other allow us to confirm that the CH4 spikes identified in one of the time series but not in the other correspond to a local source from a sewage treatment facility in one of the observatory buildings. From this experiment, we also found that the REBS method underestimates the number of positive anomalies in the CH4 data caused by local sewage emissions. As a conclusion, we recommend the use of the SD method, which also appears to be the easiest one to implement in automatic data processing, used for the operational filtering of spikes in greenhouse gases time series at global and regional monitoring stations of networks like that of the ICOS atmosphere network.
Programme: 416
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Katerina Garane, Maria-Elissavet Koukouli, Tijl Verhoelst, Christophe Lerot, Klaus-Peter Heue, Vitali Fioletov, Dimitrios Balis, Alkiviadis Bais, Ariane Bazureau, Angelika Dehn, Florence Goutail, Jose Granville, Debora Griffin, Daan Hubert, Arno Keppens, Jean-Christopher Lambert, Diego Loyola, Chris McLinden, Andrea Pazmino, Jean-Pierre Pommereau, Alberto Redondas, Fabian Romahn, Pieter Valks, Michel Van Roozendael, Jian Xu, Claus Zehner, Christos Zerefos, Walter Zimmer. (2019). TROPOMI/S5P total ozone column data: global ground-based validation and consistency with other satellite missions (Vol. 12).
Abstract: Abstract. In October 2017, the Sentinel-5 Precursor (S5P) mission was launched, carrying the TROPOspheric Monitoring Instrument (TROPOMI), which provides a daily global coverage at a spatial resolution as high as 7 km × 3.5 km and is expected to extend the European atmospheric composition record initiated with GOME/ERS-2 in 1995, enhancing our scientific knowledge of atmospheric processes with its unprecedented spatial resolution. Due to the ongoing need to understand and monitor the recovery of the ozone layer, as well as the evolution of tropospheric pollution, total ozone remains one of the leading species of interest during this mission. In this work, the TROPOMI near real time (NRTI) and offline (OFFL) total ozone column (TOC) products are presented and compared to daily ground-based quality-assured Brewer and Dobson TOC measurements deposited in the World Ozone and Ultraviolet Radiation Data Centre (WOUDC). Additional comparisons to individual Brewer measurements from the Canadian Brewer Network and the European Brewer Network (Eubrewnet) are performed. Furthermore, twilight zenith-sky measurements obtained with ZSL-DOAS (Zenith Scattered Light Differential Optical Absorption Spectroscopy) instruments, which form part of the SAOZ network (Système d'Analyse par Observation Zénitale), are used for the validation. The quality of the TROPOMI TOC data is evaluated in terms of the influence of location, solar zenith angle, viewing angle, season, effective temperature, surface albedo and clouds. For this purpose, globally distributed ground-based measurements have been utilized as the background truth. The overall statistical analysis of the global comparison shows that the mean bias and the mean standard deviation of the percentage difference between TROPOMI and ground-based TOC is within 0 –1.5 % and 2.5 %–4.5 %, respectively. The mean bias that results from the comparisons is well within the S5P product requirements, while the mean standard deviation is very close to those limits, especially considering that the statistics shown here originate both from the satellite and the ground-based measurements. Additionally, the TROPOMI OFFL and NRTI products are evaluated against already known spaceborne sensors, namely, the Ozone Mapping Profiler Suite, on board the Suomi National Polar-orbiting Partnership (OMPS/Suomi-NPP), NASA v2 TOCs, and the Global Ozone Monitoring Experiment 2 (GOME-2), on board the Metop-A (GOME-2/Metop-A) and Metop-B (GOME-2/Metop-B) satellites. This analysis shows a very good agreement for both TROPOMI products with well-established instruments, with the absolute differences in mean bias and mean standard deviation being below +0.7 % and 1 %, respectively. These results assure the scientific community of the good quality of the TROPOMI TOC products during its first year of operation and enhance the already prevalent expectation that TROPOMI/S5P will play a very significant role in the continuity of ozone monitoring from space.
Programme: 209
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