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A. Chambodut, J.M.G. Merayo, M. Menvielle and S. Vennerstroem. (2011). A Magnetometer for Mars tested at Concordia Magnetic Observatory, Antarctica .
Abstract: IUGG 2011 Melbourne Australia.
Programme: 139
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A. Chambodut, M. Menvielle, V. Mendel, J.M. Brendle, A. Bernard, A. Marchaudon, C. Lathuillère. (2015). New international service of geomagnetic indices' web site.
Abstract: 26th IUGG general assembly 2015
Programme: 139
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A. Corbeau, J. Collet, F. Orgeret, P. Pistorius, H. Weimerskirch. (2021). Fine-scale interactions between boats and large albatrosses indicate variable susceptibility to bycatch risk according to species and populations (Vol. 24).
Abstract: Many seabirds are attracted to fishing boats where they exploit foraging opportunities, often involving bycatch-related mortality. Bycatch risk is generally estimated by overlapping seabirds foraging ranges with coarse-scale monthly maps of fishing efforts, but a more direct estimation would be the time birds actually spend attending fishing boats. Here we matched data from Automatic Identification Systems from all declared boats in the Southern Ocean, with 143 simultaneous foraging trips from all populations of large albatrosses (Diomedea amsterdamensis and Diomedea exulans) breeding in the Indian Ocean (Marion, Crozet, Kerguelen, Amsterdam islands). We quantified and compared real-time co-occurrence between boats and albatrosses, at different scales (100, 30 and 5 km). We also examined to what extent co-occurrence at a large-scale (5×5° grid cell) predicted fine-scale attendance (5 km). Albatrosses on average spent about 3 h per trip attending fishing boats (<5 km) at both Amsterdam and Marion and about 30 h per trip at Kerguelen. In all populations, >90% of declared fishing boat attendances occurred within Economic Exclusive Zones (EEZ) where bycatch mitigation measures are enforced. Outside EEZs, birds from all populations to a large extent also attended non-fishing boats. Fishing boat density at a large scale (5 × 5°, 100 km) was a poor predictor of time spent attending fishing boats (<5 km) across populations. Our results indicate a large variation in fishing boat densities within the foraging ranges of different populations and in the time birds spent attending boats. We discuss the pros and cons of considering bycatch risk at a large geographical scale and methods that can be implemented to improve the estimation of seabird vulnerability to fishing activities when fine-scale data are available, particularly for the conservation of those highly threatened species.
Keywords: albatross populations biologging bycatch assessment bycatch risk ecological trap fisheries fishing boat bycatch seabirds
Programme: 109
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A. Dommergue, P. Martinerie, J. Courteaud, E. Witrant, D. M. Etheridge. (2016). A new reconstruction of atmospheric gaseous elemental mercury trend over the last 60 years from Greenland firn records (Vol. 136).
Abstract: This study presents measurements of gaseous elemental mercury (GEM) concentrations in the 80 m of firn air at the international drilling site of NEEM in Greenland (2452 m, 77°25.8 N, 51°06.4 W). Using inverse modeling, we were able to reconstruct the atmospheric GEM trend at this Arctic site over the last 60 years. We show discrepancies between this record and the previous firn record of Summit. This could be attributed to experimental biases and/or differences in air mass transport. A multisite inverse model was used to derive an atmospheric scenario reconciling the two firn records. We show that GEM seasonal variations are very limited at these high altitude sites and thus probably unaffected by spring/summer photochemistry. The firn reconstructions suggest an increase of GEM concentrations since the 1950s peaking in the late 1960s and early 1970s. A decrease is then observed with minimum GEM concentrations around 1995–2000. The reconstruction compares well with historical mercury (Hg) releases and recent simulations of atmospheric Hg. Our optimal GEM scenario does not allow to categorically conclude on recent trends for GEM concentrations over the 2000–2010 decade.
Keywords: Archive Arctic Atmospheric mercury Firn Greenland Mercury
Programme: 1025
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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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A. Fougerat, L. Guérineau, N. Tellier. (2018). High-quality signal recording down to 0.001 Hz with standard MEMS accelerometers.
Abstract: Recording very low-frequency signal below 1 hertz is a major concern for seismology, in particular passive noise tomography, and is now also considered for some oil and gas applications. The seismic sensors commonly in use for hydrocarbon deposit surveys (geophones and previous generation of MEMS accelerometers) previously had performance limitations in such applications due to their technological design with very low-frequency signal being concealed by instrument noise. Tests on a recent generation of MEMS (Micro Electro-Mechanical System) sensor with an ultra-low noise floor were performed in our lab, and showed outstanding very low-frequency performance in terms of instrument noise and full scale. A teleseism that occurred during our tests was also duly detected. Presentation Date: Tuesday, October 16, 2018 Start Time: 1:50:00 PM Location: Poster Station 10 Presentation Type: Poster
Programme: 133
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A. Ghelfi, D. Maurin, A. Cheminet, L. Derome, G. Hubert, F. Melot. (2017). Neutron monitors and muon detectors for solar modulation studies: 2. ϕ time series (Vol. 60).
Abstract: The level of solar modulation at different times (related to the solar activity) is a central question of solar and galactic cosmic-ray physics. In the first paper of this series, we have established a correspondence between the uncertainties on ground-based detectors count rates and the parameter ϕ (modulation level in the force-field approximation) reconstructed from these count rates. In this second paper, we detail a procedure to obtain a reference ϕ time series from neutron monitor data. We show that we can have an unbiased and accurate ϕ reconstruction (Δϕ/ϕ≃10%). We also discuss the potential of Bonner spheres spectrometers and muon detectors to provide ϕ time series. Two by-products of this calculation are updated ϕ values for the cosmic-ray database and a web interface to retrieve and plot ϕ from the 50’s to today (http://lpsc.in2p3.fr/crdb).
Keywords: Cosmic rays Muon detector Neutron monitor Solar modulation
Programme: 1112
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A. Ghelfi, D. Maurin, A. Cheminet, L. Derome, G. Hubert, F. Melot. (2017). Neutron monitors and muon detectors for solar modulation studies: 2. ϕ time series (Vol. 60).
Abstract: The level of solar modulation at different times (related to the solar activity) is a central question of solar and galactic cosmic-ray physics. In the first paper of this series, we have established a correspondence between the uncertainties on ground-based detectors count rates and the parameter ϕ (modulation level in the force-field approximation) reconstructed from these count rates. In this second paper, we detail a procedure to obtain a reference ϕ time series from neutron monitor data. We show that we can have an unbiased and accurate ϕ reconstruction (Δϕ/ϕ≃10%). We also discuss the potential of Bonner spheres spectrometers and muon detectors to provide ϕ time series. Two by-products of this calculation are updated ϕ values for the cosmic-ray database and a web interface to retrieve and plot ϕ from the 50’s to today (http://lpsc.in2p3.fr/crdb).
Keywords: Cosmic rays Muon detector Neutron monitor Solar modulation
Programme: 1112
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A. Goutte, A. Meillère, C. Barbraud, H. Budzinski, P. Labadie, L. Peluhet, H. Weimerskirch, K. Delord, O. Chastel. (2018). Demographic, endocrine and behavioral responses to mirex in the South polar skua (Vol. 631-632).
Abstract: Population consequences of chronic exposure to multiple pollutants at low environmental doses remain speculative, because of the lack of appropriate long-term monitoring surveys. This study integrates proximate and ultimate aspects of persistent organic pollutants (POP) burden in free-living vertebrates, by coupling hormonal and behavioral endpoints, life-history traits, and population dynamics. Blood samples (N=70) were collected in South polar skuas during two breeding periods, in 2003 and 2005, and individuals were annually monitored until 2011. Multi-state mark recapture models were used to test the effects of POP levels on demographic traits. Survival rate and long-term breeding probability were not related to individual POP levels, whereas long-term breeding success significantly decreased with increasing blood levels of mirex, an organochlorine insecticide. At the proximate level, corticosterone (stress hormone) and prolactin (parental care hormone) levels were not linked to individual POP burden. Nest defense in 2005 was significantly less intensive in chick-rearing skuas bearing higher mirex levels, suggesting reproductive behavioral impairment. Matrix population models were then built to project the rate of population decline according to increasing mirex burden. Although mirex levels were 2.8 times higher in 2003 than in 2005, the population-level effect of mirex was only detected in 2005, the year of higher corticosterone levels. The combination of endocrine traits with demographic analysis thereby enables to provide new support of synergistic interactions between pollutants and stress levels on long-term breeding outputs and population dynamics.
Keywords: Capture–mark–recapture Ecotoxicology Population dynamics Vital rates
Programme: 109
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A. Goutte, Y. Cherel, C. Ozouf-Costaz, C. Robineau, J. Lanshere, G. Massé. (2014). Contribution of sea ice organic matter in the diet of Antarctic fishes: a diatom-specific highly branched isoprenoid approach (Vol. 37).
Abstract: New sets of diatom-specific biomarkers, highly branched isoprenoids (HBIs), have been recently proposed to trace carbon flow from ice algae and pelagic phytoplankton to higher trophic level organisms. In the Antarctic, diene, a HBI of sea ice origin was more abundant in ice-associated species, while triene, a HBI of phytoplanktonic origin, was more abundant in pelagic species. However, this HBI approach has never been applied on Antarctic benthic species. Here, we analyzed diene and triene in the liver and the muscle of eight Antarctic coastal fish species (108 specimens). HBI lipids were detected in all specimens, confirming the contribution of sea ice and pelagic organic matter in coastal benthic fish species. Moreover, HBI markers were much more concentrated in the liver than in white muscle, and the relative concentrations of diene and triene strongly varied among species, as a probable result of species differences in feeding habits and trophic ecology. Seasonal variations in HBI concentrations were detected during the whole year in white muscle, but not in the liver. These findings are consistent with the well-known spring bloom in November–December, just before the annual ice break up, and the second proliferation of ice algae during the land-fast ice formation, in April–May. Therefore, investigation of HBI lipids in white muscle will likely shed new light on seasonal changes in the contribution of ice algal-derived organic matter in higher trophic level organisms.
Programme: 1010
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