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B. Lauer, R. Grandin, Y. Klinger. (2020). Fault Geometry and Slip Distribution of the 2013 Mw 7.7 Balochistan Earthquake From Inversions of SAR and Optical Data (Vol. 125).
Abstract: The 2013 Mw 7.7 Balochistan earthquake ruptured the Hoshab fault (Pakistan) over 200 km. It was dominated by left-lateral slip, with a secondary reverse component. By combining optical (SPOT 5 and Landsat 8) and radar satellite data (RADARSAT-2 and TerraSAR-X ScanSAR), we derive the 3-D coseismic displacement field and the slip distribution. Our modeling strategy involves two successive inversions allowing to explore first the fault geometry and then slip distribution. Following a statistical analysis of the coseismic surface trace, the fault is discretized into 16 segments. To determine the dip angle and down-dip width of the segments, we then perform a non-linear elastic inversion of the geodetic data set. Using output of this model, we prescribe the fault geometry and linearly invert for slip at depth with refined discretization. Results show a decrease of the fault dip, reaching 50° in the central part of the fault that structurally connects the two sub-vertical terminations dipping at >70°. The distribution of strike-slip forms a shallow continuous patch (0–8 km) that peaks at 12.7 m of slip near the epicenter. Reverse slip is distributed on several patches and becomes shallower near the southern termination, where it peaks at 5.7 m. Our model shows an absence of shallow slip deficit (SSD), as for other Mw 7.5 + strike-slip earthquakes elsewhere, hence suggesting that SSD is only found for lesser magnitude earthquakes. We speculate that moment magnitude is a key element in the occurrence of SSD.
Keywords: Balochistan earthquake earthquake rupture modeling earthquake source processes InSAR optical data shallow slip deficit
Programme: 133
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Vincent A. Viblanc, Quentin Schull, Antoine Stier, Laureline Durand, Emilie Lefol, Jean-Patrice Robin, Sandrine Zahn, Pierre Bize, François Criscuolo. (2020). Foster rather than biological parental telomere length predicts offspring survival and telomere length in king penguins.
Abstract: Because telomere length and dynamics relate to individual growth, reproductive investment and survival, telomeres have emerged as possible markers of individual quality. Here, we tested the hypothesis that, in species with parental care, parental telomere length can be a marker of parental quality that predicts offspring phenotype and survival. In king penguins (Aptenodytes patagonicus), we experimentally swapped the single egg of 66 breeding pairs just after egg laying to disentangle the contribution of prelaying parental quality (e.g., genetics, investment in the egg) and/or postlaying parental quality (e.g., incubation, postnatal feeding rate) on offspring growth, telomere length and survival. Parental quality was estimated through the joint effects of biological and foster parent telomere length on offspring traits, both soon after hatching (day 10) and at the end of the prewinter growth period (day 105). We expected that offspring traits would be mostly related to the telomere lengths (i.e., quality) of biological parents at day 10 and to the telomere lengths of foster parents at day 105. Results show that chick survival up to 10 days was negatively related to biological fathers’ telomere length, whereas survival up to 105 days was positively related to foster fathers’ telomere lengths. Chick growth was not related to either biological or foster parents’ telomere length. Chick telomere length was positively related to foster mothers’ telomere length at both 10 and 105 days. Overall, our study shows that, in a species with biparental care, parents’ telomere length is foremost a proxy of postlaying parental care quality, supporting the “telomere – parental quality hypothesis.”
Keywords: gene and early life environmental effects growth penguins reproduction investment telomere
Programme: 119
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Ross J. Turner, Martin Gal, Mark A. Hemer, Anya M. Reading. (2020). Impacts of the Cryosphere and Atmosphere on Observed Microseisms Generated in the Southern Ocean (Vol. 125).
Abstract: The Southern Ocean (in the region 60–180° E) south of the Indian Ocean, Australia, and the West Pacific is noted for the frequent occurrence and severity of its storms. These storms give rise to high-amplitude secondary microseisms from sources, including the deep ocean regions, and primary microseisms where the swells impinge on submarine topographic features. A better understanding of the varying microseism wavefield enables improvements to seismic imaging and development of proxy observables to complement sparse in situ wave observations and hindcast models of the global ocean wave climate. We analyze 12–26 years of seismic data from 11 seismic stations either on the East Antarctic coast or sited in the Indian Ocean, Australia, and New Zealand. The power spectral density of the seismic wavefield is calculated to explore how the time-changing microseism intensity varies with (i) sea ice coverage surrounding Antarctica and (ii) the Southern Annular Mode (SAM) climate index. Variations in sea ice extent are found to be the dominant control on the microseism intensity at Antarctic stations, which exhibit a seasonal pattern phase-shifted by 4–5 months compared to stations in other continents. Peaks in extremal intensity at East Antarctic stations occur in March–April, with the highest peaks for secondary microseisms occurring during negative SAM events. This relationship between microseism intensity and the SAM index is opposite to that observed on the Antarctic Peninsula. This work informs the complexity of microseism amplitudes in the Southern Hemisphere and assists ongoing interdisciplinary investigations of interannual variability and long-term trends.
Programme: 133
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Vojtěch Brlík, Jaroslav Koleček, Malcolm Burgess, Steffen Hahn, Diana Humple, Miloš Krist, Janne Ouwehand, Emily L. Weiser, Peter Adamík, José A. Alves, Debora Arlt, Sanja Barišić, Detlef Becker, Eduardo J. Belda, Václav Beran, Christiaan Both, Susana P. Bravo, Martins Briedis, Bohumír Chutný, Davor Ćiković, Nathan W. Cooper, Joana S. Costa, Víctor R. Cueto, Tamara Emmenegger, Kevin Fraser, Olivier Gilg, Marina Guerrero, Michael T. Hallworth, Chris Hewson, Frédéric Jiguet, James A. Johnson, Tosha Kelly, Dmitry Kishkinev, Michel Leconte, Terje Lislevand, Simeon Lisovski, Cosme López, Kent P. McFarland, Peter P. Marra, Steven M. Matsuoka, Piotr Matyjasiak, Christoph M. Meier, Benjamin Metzger, Juan S. Monrós, Roland Neumann, Amy Newman, Ryan Norris, Tomas Pärt, Václav Pavel, Noah Perlut, Markus Piha, Jeroen Reneerkens, Christopher C. Rimmer, Amélie Roberto‐Charron, Chiara Scandolara, Natalia Sokolova, Makiko Takenaka, Dirk Tolkmitt, Herman van Oosten, Arndt H. J. Wellbrock, Hazel Wheeler, Jan van der Winden, Klaudia Witte, Bradley K. Woodworth, Petr Procházka. (2020). Weak effects of geolocators on small birds: A meta-analysis controlled for phylogeny and publication bias (Vol. 89).
Abstract: Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light-level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta-analyses did not evaluate unpublished data and impact of multiple life-history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially. We quantitatively reviewed 549 records extracted from 74 published and 48 unpublished studies on over 7,800 tagged and 17,800 control individuals to examine the effects of geolocator tagging on small bird species (body mass <100 g). We calculated the effect of tagging on apparent survival, condition, phenology and breeding performance and identified the most important predictors of the magnitude of effect sizes. Even though the effects were not statistically significant in phylogenetically controlled models, we found a weak negative impact of geolocators on apparent survival. The negative effect on apparent survival was stronger with increasing relative load of the device and with geolocators attached using elastic harnesses. Moreover, tagging effects were stronger in smaller species. In conclusion, we found a weak effect on apparent survival of tagged birds and managed to pinpoint key aspects and drivers of tagging effects. We provide recommendations for establishing matched control group for proper effect size assessment in future studies and outline various aspects of tagging that need further investigation. Finally, our results encourage further use of geolocators on small bird species but the ethical aspects and scientific benefits should always be considered.
Keywords: condition migration phenology reproduction return rate survival tag effect tracking device
Programme: 1036
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Helle A. Pedersen, Nicolas Leroy, Dimitri Zigone, Martin Vallée, Adam T. Ringler, David C. Wilson. (2020). Using Component Ratios to Detect Metadata and Instrument Problems of Seismic Stations: Examples from 18 Yr of GEOSCOPE Data (Vol. 91).
Abstract: Replacement or deterioration of seismic instruments and the evolution of the installation conditions and sites can alter the seismic signal in very subtle ways; therefore, it is notoriously difficult to monitor the signal quality of permanent seismic stations. We present a simple way to characterize and monitor signal quality, using energy ratios between each pair of the three components, as a complement to existing methods. To calculate stable daily energy ratios over a large frequency range (0.01–5 Hz), we use the daily median energy ratio over all 5 min windows within the day. The method is applied to all GEOSCOPE stations, for continuous BH channel data collected since 2001. We show applications to identify past gain problems (stations ROCAM and CRZF), to provide feedback after field interventions at remote sites (Antarctic station DRV), and to shed light on complex instrument problems (stations ECH and KIP). Our results show that component energy ratios have excellent time resolution and that they are visually simple for identification of problems. They can be used both for ongoing continuous monitoring of the signal quality, or as a tool to identify past problems. The Python code to produce the results in this work and the Python code for daily monitoring used by GEOSCOPE are available (see Data and Resources).
Programme: 133
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Stéphanie Jenouvrier, Marika Holland, David Iles, Sara Labrousse, Laura Landrum, Jimmy Garnier, Hal Caswell, Henri Weimerskirch, Michelle LaRue, Rubao Ji, Christophe Barbraud. (2020). The Paris Agreement objectives will likely halt future declines of emperor penguins (Vol. 26).
Abstract: The Paris Agreement is a multinational initiative to combat climate change by keeping a global temperature increase in this century to 2°C above preindustrial levels while pursuing efforts to limit the increase to 1.5°C. Until recently, ensembles of coupled climate simulations producing temporal dynamics of climate en route to stable global mean temperature at 1.5 and 2°C above preindustrial levels were not available. Hence, the few studies that have assessed the ecological impact of the Paris Agreement used ad-hoc approaches. The development of new specific mitigation climate simulations now provides an unprecedented opportunity to inform ecological impact assessments. Here we project the dynamics of all known emperor penguin (Aptenodytes forsteri) colonies under new climate change scenarios meeting the Paris Agreement objectives using a climate-dependent-metapopulation model. Our model includes various dispersal behaviors so that penguins could modulate climate effects through movement and habitat selection. Under business-as-usual greenhouse gas emissions, we show that 80% of the colonies are projected to be quasiextinct by 2100, thus the total abundance of emperor penguins is projected to decline by at least 81% relative to its initial size, regardless of dispersal abilities. In contrast, if the Paris Agreement objectives are met, viable emperor penguin refuges will exist in Antarctica, and only 19% and 31% colonies are projected to be quasiextinct by 2100 under the Paris 1.5 and 2 climate scenarios respectively. As a result, the global population is projected to decline by at least by 31% under Paris 1.5 and 44% under Paris 2. However, population growth rates stabilize in 2060 such that the global population will be only declining at 0.07% under Paris 1.5 and 0.34% under Paris 2, thereby halting the global population decline. Hence, global climate policy has a larger capacity to safeguard the future of emperor penguins than their intrinsic dispersal abilities.
Keywords: Antarctica climate change mitigation dispersion emission reduction pledges seabirds
Programme: 109
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Sacré N. (2020). Modélisation des réseaux trophiques dans les environnements marins côtiers des Iles Kerguelen.
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Meudec L. (2020). Caractérisation des habitats marins benthiques en zones côtières aux Iles Kerguelen par analyse d’images sous-marines.
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Natacha Garcin. (2020). The effects of stress hormones on king penguin's growth, energetics and ageing rate.
Abstract: Stress exposure and stress response are likely to vary according to life history strategies and across environmental contexts. If the release of glucocorticoids (e.g. corticosterone, CORT) in response to acute stress enables animals to rightfully cope with the situation, chronic exposure to high CORT levels can lead to deleterious cascading effects on animal’s physiology, behavior and fitness. Some species may be more adapted to cope with stressful events than others and might exhibit natural adaptations to limit the adverse consequences of prolonged high CORT levels. The aim of this study was to investigate the effects of experimentally elevated CORT levels on the growth, energetics and ageing of king penguin chicks (Aptenodytes patagonicus), using sub-cutaneous CORT implants. We investigated the effects of CORT both on the medium (23 days
after implant) and the long-term (fledging: ~ 200 days after the implant) on morphological (i.e. body mass and size), behavioral (i.e. aggressivity, physical activity) and physiological traits (i.e. heart rate, CORT response to acute stress, oxidative stress, mitochondrial density and telomere length). Although CORT-treated chicks were taller, more aggressive and displayed lower CORT response to acute stress on the medium-term, there was no significant impact of CORT on the body mass and whole-body energetics assessed through heart rate and physical activity. Moreover, CORT chicks displayed lower oxidized glutathione on the medium and long-term, thus indirectly preventing
oxidative damage, while telomere length and mitochondrial density were not influenced by CORT implants. Although chronic elevation of glucocorticoid levels is mostly known to result in negative physiological and behavioral outcomes, our results indicating some positive effects of CORT implants are consistent with the hypothesis that species who encounter several noxious stressors in their environment, could be naturally adapted to cope with them. The growth-enhancing effect of CORT might be mediated by a higher efficiency at which food is assimilated and/or used, and CORT chicks might benefit from aggressive behaviors during competitive interactions or predation
encounters. Through the antioxidant glutathione system, CORT treated chicks seem to have developed a resistance to oxidative stress that could last over time (i.e. possibly through a reduction
of ROS production). While CORT implants did not accelerate ageing or bring short and mediumterm costs, possible long lasting programming effects of CORT should be further investigated.
Programme: 119
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Pierre Friedlingstein, Michael O'Sullivan, Matthew W. Jones, Robbie M. Andrew, Judith Hauck, Are Olsen, Glen P. Peters, Wouter Peters, Julia Pongratz, Stephen Sitch, Corinne Le Quéré, Josep G. Canadell, Philippe Ciais, Robert B. Jackson, Simone Alin, Luiz E. O. C. Aragão, Almut Arneth, Vivek Arora, Nicholas R. Bates, Meike Becker, Alice Benoit-Cattin, Henry C. Bittig, Laurent Bopp, Selma Bultan, Naveen Chandra, Frédéric Chevallier, Louise P. Chini, Wiley Evans, Liesbeth Florentie, Piers M. Forster, Thomas Gasser, Marion Gehlen, Dennis Gilfillan, Thanos Gkritzalis, Luke Gregor, Nicolas Gruber, Ian Harris, Kerstin Hartung, Vanessa Haverd, Richard A. Houghton, Tatiana Ilyina, Atul K. Jain, Emilie Joetzjer, Koji Kadono, Etsushi Kato, Vassilis Kitidis, Jan Ivar Korsbakken, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Zhu Liu, Danica Lombardozzi, Gregg Marland, Nicolas Metzl, David R. Munro, Julia E. M. S. Nabel, Shin-Ichiro Nakaoka, Yosuke Niwa, Kevin O'Brien, Tsuneo Ono, Paul I. Palmer, Denis Pierrot, Benjamin Poulter, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Adam J. P. Smith, Adrienne J. Sutton, Toste Tanhua, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Guido van der Werf, Nicolas Vuichard, Anthony P. Walker, Rik Wanninkhof, Andrew J. Watson, David Willis, Andrew J. Wiltshire, Wenping Yuan, Xu Yue, Sönke Zaehle. (2020). Global Carbon Budget 2020 (Vol. 12).
Abstract: Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFOS) are based on energy statistics and cement production data, while emissions from land-use change (ELUC), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2010–2019), EFOS was 9.6 ± 0.5 GtC yr−1 excluding the cement carbonation sink (9.4 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and ELUC was 1.6 ± 0.7 GtC yr−1. For the same decade, GATM was 5.1 ± 0.02 GtC yr−1 (2.4 ± 0.01 ppm yr−1), SOCEAN 2.5 ± 0.6 GtC yr−1, and SLAND 3.4 ± 0.9 GtC yr−1, with a budget imbalance BIM of −0.1 GtC yr−1 indicating a near balance between estimated sources and sinks over the last decade. For the year 2019 alone, the growth in EFOS was only about 0.1 % with fossil emissions increasing to 9.9 ± 0.5 GtC yr−1 excluding the cement carbonation sink (9.7 ± 0.5 GtC yr−1 when cement carbonation sink is included), and ELUC was 1.8 ± 0.7 GtC yr−1, for total anthropogenic CO2 emissions of 11.5 ± 0.9 GtC yr−1 (42.2 ± 3.3 GtCO2). Also for 2019, GATM was 5.4 ± 0.2 GtC yr−1 (2.5 ± 0.1 ppm yr−1), SOCEAN was 2.6 ± 0.6 GtC yr−1, and SLAND was 3.1 ± 1.2 GtC yr−1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 409.85 ± 0.1 ppm averaged over 2019. Preliminary data for 2020, accounting for the COVID-19-induced changes in emissions, suggest a decrease in EFOS relative to 2019 of about −7 % (median estimate) based on individual estimates from four studies of −6 %, −7 %, −7 % (−3 % to −11 %), and −13 %. Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2019, but discrepancies of up to 1 GtC yr−1 persist for the representation of semi-decadal variability in CO2 fluxes. Comparison of estimates from diverse approaches and observations shows (1) no consensus in the mean and trend in land-use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent discrepancy between the different methods for the ocean sink outside the tropics, particularly in the Southern Ocean. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Friedlingstein et al., 2019; Le Quéré et al., 2018b, a, 2016, 2015b, a, 2014, 2013). The data presented in this work are available at https://doi.org/10.18160/gcp-2020 (Friedlingstein et al., 2020).
Programme: 416
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