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J. Rojas, J. Duprat, C. Engrand, E. Dartois, L. Delauche, M. Godard, M. Gounelle, J. D. Carrillo-Sánchez, P. Pokorný, J. M. C. Plane. (2021). The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth (Vol. 560).
Abstract: The annual flux of extraterrestrial material on Earth is largely dominated by sub-millimetre particles. The mass distribution and absolute value of this cosmic dust flux at the Earth's surface is however still uncertain due to the difficulty in monitoring both the collection efficiency and the exposure parameter (i.e. the area-time product in m2.yr). In this paper, we present results from micrometeorite collections originating from the vicinity of the CONCORDIA Station located at Dome C (Antarctica), where we performed several independent melts of large volumes of ultra-clean snow. The regular precipitation rate and the exceptional cleanliness of the snow from central Antarctica allow a unique control on both the exposure parameter and the collection efficiency. A total of 1280 unmelted micrometeorites (uMMs) and 808 cosmic spherules (CSs) with diameters ranging from 30 to 350 μm were identified. Within that size range, we measured mass fluxes of 3.0 μg.m−2.yr−1 for uMMs and 5.6 μg.m−2.yr−1 for CSs. Extrapolated to the global flux of particles in the 12-700 μm diameter range, the mass flux of dust at Earth's surface is 5,200±12001500 tons.yr−1 (1,600±500 and 3,600±7001000 tons.yr−1 of uMMs and CSs, respectively). We indicate the statistical uncertainties expected for collections with exposure parameters in the range of 0.1 up to 105 m2.yr. In addition, we estimated the flux of altered and unaltered carbon carried by heated and un-heated particles at Earth's surface. The mass distributions of CSs and uMMs larger than 100 μm are fairly well reproduced by the CABMOD-ZoDy model that includes melting and evaporation during atmospheric entry of the interplanetary dust flux. These numerical simulations suggest that most of the uMMs and CSs originate from Jupiter family comets and a minor part from the main asteroid belt. The total dust mass input before atmospheric entry is estimated at 15,000 tons.yr−1. The existing discrepancy between the flux data and the model for uMMs below 100 μm suggests that small fragile uMMs may evade present day collections, and/or that the amount of small interplanetary particles at 1 AU may be smaller than expected.
Keywords: Antarctic micrometeorites atmospheric entry cosmic spherules extraterrestrial flux interplanetary dust particles zodiacal cloud
Programme: 1120
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Chiara Papetti, Massimiliano Babbucci, Agnes Dettai, Andrea Basso, Magnus Lucassen, Lars Harms, Celine Bonillo, Franz Maximilian Heindler, Tomaso Patarnello, Enrico Negrisolo. (2021). Not Frozen in the Ice: Large and Dynamic Rearrangements in the Mitochondrial Genomes of the Antarctic Fish (Vol. 13).
Abstract: The vertebrate mitochondrial genomes generally present a typical gene order. Exceptions are uncommon and important to study the genetic mechanisms of gene order rearrangements and their consequences on phylogenetic output and mitochondrial function. Antarctic notothenioid fish carry some peculiar rearrangements of the mitochondrial gene order. In this first systematic study of 28 species, we analyzed known and undescribed mitochondrial genome rearrangements for a total of eight different gene orders within the notothenioid fish. Our reconstructions suggest that transpositions, duplications, and inversion of multiple genes are the most likely mechanisms of rearrangement in notothenioid mitochondrial genomes. In Trematominae, we documented an extremely rare inversion of a large genomic segment of 5,300 bp that partially affected the gene compositional bias but not the phylogenetic output. The genomic region delimited by nad5 and trnF, close to the area of the Control Region, was identified as the hot spot of variation in Antarctic fish mitochondrial genomes. Analyzing the sequence of several intergenic spacers and mapping the arrangements on a newly generated phylogeny showed that the entire history of the Antarctic notothenioids is characterized by multiple, relatively rapid, events of disruption of the gene order. We hypothesized that a pre-existing genomic flexibility of the ancestor of the Antarctic notothenioids may have generated a precondition for gene order rearrangement, and the pressure of purifying selection could have worked for a rapid restoration of the mitochondrial functionality and compactness after each event of rearrangement.
Programme: 1124
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Jesús A Ballesteros, Emily V W Setton, Carlos E Santibáñez-López, Claudia P Arango, Georg Brenneis, Saskia Brix, Kevin F Corbett, Esperanza Cano-Sánchez, Merai Dandouch, Geoffrey F Dilly, Marc P Eleaume, Guilherme Gainett, Cyril Gallut, Sean McAtee, Lauren McIntyre, Amy L Moran, Randy Moran, Pablo J López-González, Gerhard Scholtz, Clay Williamson, H Arthur Woods, Jakob T Zehms, Ward C Wheeler, Prashant P Sharma. (2021). Phylogenomic Resolution of Sea Spider Diversification through Integration of Multiple Data Classes (Vol. 38).
Abstract: Despite significant advances in invertebrate phylogenomics over the past decade, the higher-level phylogeny of Pycnogonida (sea spiders) remains elusive. Due to the inaccessibility of some small-bodied lineages, few phylogenetic studies have sampled all sea spider families. Previous efforts based on a handful of genes have yielded unstable tree topologies. Here, we inferred the relationships of 89 sea spider species using targeted capture of the mitochondrial genome, 56 conserved exons, 101 ultraconserved elements, and 3 nuclear ribosomal genes. We inferred molecular divergence times by integrating morphological data for fossil species to calibrate 15 nodes in the arthropod tree of life. This integration of data classes resolved the basal topology of sea spiders with high support. The enigmatic family Austrodecidae was resolved as the sister group to the remaining Pycnogonida and the small-bodied family Rhynchothoracidae as the sister group of the robust-bodied family Pycnogonidae. Molecular divergence time estimation recovered a basal divergence of crown group sea spiders in the Ordovician. Comparison of diversification dynamics with other marine invertebrate taxa that originated in the Paleozoic suggests that sea spiders and some crustacean groups exhibit resilience to mass extinction episodes, relative to mollusk and echinoderm lineages.
Programme: 1124
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Dedieu, J.-P., A. Wendleder, B. Cerino, J. Boike, E. Bernard, J.-C. Gallet, and H.-W. Jacobi. (2021). Snow change detection from polarimetric SAR time-series at X-band (Svalbard, Norway), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-149..
Abstract: Due to recent climate change conditions, i.e. increasing temperatures and changing precipitation patterns, arctic snow cover dynamics exhibit strong changes in terms of extent and duration. Arctic amplification processes and impacts are well documented expected to strengthen in coming decades. In this context, innovative observation methods are helpful for a better comprehension of the spatial variability of snow properties relevant for climate research and hydrological applications. Microwave remote sensing provides exceptional spatial and temporal performance in terms of all-weather application and target penetration. Time-series of Synthetic Active Radar images (SAR) are becoming more accessible at different frequencies and polarimetry has demonstrated a significant advantage for detecting changes in different media. Concerning arctic snow monitoring, SAR sensors can offer continuous time-series during the polar night and with cloud cover, providing a consequent advantage in regard of optical sensors. The aim of this study is dedicated to the spatial/temporal variability of snow in the Ny-Ålesund area on the Br∅gger peninsula, Svalbard (N 78°55’ / E 11° 55’). The TerraSAR-X satellite (DLR, Germany) operated at X-band (3.1 cm, 9.6 GHz) with dual co-pol mode (HH/VV) at 5-m spatial resolution, and with high incidence angles (36° to 39°) poviding a better snow penetration and reducing topographic constraints. A dataset of 92 images (ascending and descending) is available since 2017, together with a high resolution DEM (NPI 5-m) and consistent in-situ measurements of meteorological data and snow profiles including glaciers sites. Polarimetric processing is based on the Kennaugh matrix decomposition, copolar phase coherence (CCOH) and copolar phase difference (CPD). The Kennaugh matrix elements K0, K3, K4, and K7 are, respectively, the total intensity, phase ratio, intensity ratio, and shift between HH and VV phase center. Their interpretation allows analysing the structure of the snowpack linked to the near real time of in-situ measurements (snow profiles). The X-band signal is strongly influenced by the snow stratigraphy: internal ice layers reduce or block the penetration of the signal into the snow pack. The best R2 correlation performances between estimated and measured snow heights are ranging from 0.50 to 0.70 for dry snow conditions. Therefore, the use of the X-band for regular snow height estimations remains limited under these conditions. Conversely, this study shows the benefit of TerraSAR-X thanks to the Kennaugh matrix elements analysis. A focus is set on the Copolar Phase Difference (CPD, Leinss 2016) between VV and HH polarization: Φ CPD = Φ VV – Φ HH. Our results indicate that the CPD values are related to the snow metamorphism: positive values correspond to dry snow (horizontal structures), negative values indicate recrystallization processes (vertical structures). Backscattering evolution in time offer a good proxy for meteorological events detection, impacting on snow metamorphism. Fresh snowfalls or melting processes can then be retrieved at the regional scale and linked to air temperature or precipitation measurements at local scale. Polarimetric SAR time series is therefore of interest to complement satellite-based precipitation measurements in the Arctic.
Programme: 1126
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Lucien Goulet. (2021). Télédétection radar en bande X appliquée à la neige sur la péninsule de Brøgger (Svalbard).
Abstract: Dans un contexte de changement climatique, il est important de déterminer avec précision l’évolution actuelle et future des processus environnementaux pouvant avoir un impact sur les populations. Ainsi, connaitre l’évolution saisonnière du couvert neigeux s’avère crucial car c’est une composante du cycle de l’eau, jouant un rôle de stockage au printemps. La télédétection spatiale joue un rôle important pour le suivi de l’évolution du manteau neigeux aux échelles continentale et régionale. Des études ont déjà mis en avant certains avantages du radar en bande X (notamment son signal de phase). L’analyse du lien entre la réponse de plusieurs paramètres polarimétriques (K0, K3, K4, K7, CCOH et le CPD) et des données météorologiques (dont l’épaisseur du manteau), a permis de conforter l’utilité de la bande X pour la cible neige. On note un intérêt pour l’intensité totale (K0) qui s’avère être intéressante pour l’étude de la hauteur totale de neige. La différence de phase (CPD), ne s’avère pas concluante pour retracer l’épaisseur totale du manteau neigeux dans notre cas d’application. En revanche, elle offre un bon diagnostic des chutes de neige fraiche et pour la cartographie du métamorphisme de la neige.
Programme: 1126
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Alexandra Lavrillier, Semen Gabyshev, Liudmila Egorova, Galina Makarova, Maia Lomovtseva-Adukanova. (2021). Analysing Non-Existent and Existing Tourisms in Eastern Siberia among the Evenki, Even, Koryak and Itelmen.
Abstract: Depuis l'effondrement de l'Union soviétique, les villageois et les nomades autochtones sibériens ont souvent eu du mal à subvenir à leurs besoins. Certains natifs pensent que l'ethno-tourisme peut être une source de revenus, mais il y a actuellement peu de tourisme en Sibérie. Dans l'Arctique circumpolaire, le tourisme est présenté comme une source de croissance économique. Le Plan Officiel de Développement Economique de la Fédération de Russie à l'Horizon 2030 vise également le développement du tourisme et, à cette fin, la Russie mobilise des équipes spécialisées. Quelles seront les conséquences économiques, sociales et culturelles pour les communautés autochtones? Quelles formes de tourisme leur seraient bénéfiques ? Quelles perceptions les autochtones de Sibérie ont-ils du tourisme ?Cet article transdisciplinaire compare le tourisme inexistant, tel qu'il est imaginé, souhaité ou déploré par les citadins, les villageois, les éleveurs nomades autochtones de la République Sakha-Yakoutie et de la région de l'Amour, avec diverses expériences d’ethno-tourisme existants au Kamtchatka. Basé sur des données ethnographiques recueillies entre 1994 et 2016, l'article a utilisé les méthodes de terrains participatifs et de l’anthropologie classique, et des mises en hypothèses effectuées par des co-chercheurs autochtones et un anthropologue. Il analyse les aspects économiques, sociaux, culturels et administratifs des tourismes existants et non existants.
Keywords: changement culturel communautés autochtones economies Even Evenk invention de la tradition Itelmen Koriak nomades Russie Sibérie Tourisme
Programme: 1127
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Alexandra Lavrillier, Semen Gabyshev. (2021). An Indigenous science of the climate change impacts on landscape topography in Siberia (Vol. 50).
Abstract: As with many Indigenous Peoples, the Siberian Evenki nomadic reindeer herders and hunters have observed increasing consequences of climate change on the cryosphere and biodiversity. Since 2017, they have observed previously unthinkable changes in topography. Based exclusively on an Evenki Indigenous Ecological Knowledge system-social anthropology coproduction and community-based continuous observation from 2013, this paper analyses what a Subarctic People observes, knows, does not know, hypothesizes, and models (collectively or individually) about climate change impacts on Indigenous landscape types typical for local river systems. These landscapes are crucial tools for traditional activities. To the nomads, the landscape changes emerge from general anomalies: competition from new plant species; atmosphere–ground–vegetation interactions; icing blisters decrease; rising receding river water interactions; the formation of new soil, ice, and snow types; increasing ground, air, and water temperatures; and the (non)circulation of harsh air throughout the snowpack. We demonstrate the science-like structure and value of Indigenous typologies and hypotheses.
Programme: 1127
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Lavrillier, A., Gabyshev S. (2021). A Siberian Indigenous Knowledge System for Understanding Climate Change (Vol. II).
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Lavrillier A. (2021). Le pas léger sur la Terre des peuples des neiges (Vol. Hors-Série).
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Armelle Decaulne, Najat Bhiry, Janie Faucher-Roy, Clara Pelletier Boily. (2021). The development of Kangiqsualujjuaq and the threat of snow avalanches in a permafrost degradation context, Nunavik, Canada.
Abstract: Slope processes are active in the rolling plateau landscapes of Nunavik, Northern Québec, Canada. There are a few short but very steep escarpments in this region. On January 1st, 1999 a powerful snow avalanche struck Kangiqsualujjuaq, one of the 14 Inuit villages in Nunavik. Nine people died and 25 were injured. This village and its surrounding are located within a glacial valley, in a periglacial environment. There is significant population growth, as well as in the other villages in Nunavik. As early as 1999-2000, there was a significant spatial reorganization of the village's infrastructures to avoid the impact of other snow-avalanche events. The main objective of this paper is to examine the village expansion in response to snow-avalanche process and population growth, within an area constrained with permafrost thawing and steep slopes. From naturalist geomorphologic methods, written sources such as archive documents and aerial photographs, the results show that slopes above Kangiqsualujjuaq are prone to release snow avalanches during blizzards from uncommon directions, and that the newly built housing may be at risk in some places, due to the conjunction of snow avalanches and permafrost thawing.
Keywords: active layer Canada demographic growth Nordic village slopes snow avalanches
Programme: 1148
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