. (2020). Sex-specific effects of wind on the flight decisions of a sexually dimorphic soaring bird (Vol. 89).
Keywords: biologging foraging behaviour hidden Markov model movement ecology niche specialization optimization sexual segregation wandering albatross
Programme: 109
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. (2020). Detecting Regime Transitions of the Nocturnal and Polar Near-Surface Temperature Inversion (Vol. 77).
Abstract: Abstract Many natural systems undergo critical transitions, i.e., sudden shifts from one dynamical regime to another. In the climate system, the atmospheric boundary layer can experience sudden transitions between fully turbulent states and quiescent, quasi-laminar states. Such rapid transitions are observed in polar regions or at night when the atmospheric boundary layer is stably stratified, and they have important consequences in the strength of mixing with the higher levels of the atmosphere. To analyze the stable boundary layer, many approaches rely on the identification of regimes that are commonly denoted as weakly and very stable regimes. Detecting transitions between the regimes is crucial for modeling purposes. In this work a combination of methods from dynamical systems and statistical modeling is applied to study these regime transitions and to develop an early warning signal that can be applied to nonstationary field data. The presented metric aims to detect nearing transitions by statistically quantifying the deviation from the dynamics expected when the system is close to a stable equilibrium. An idealized stochastic model of near-surface inversions is used to evaluate the potential of the metric as an indicator of regime transitions. In this stochastic system, small-scale perturbations can be amplified due to the nonlinearity, resulting in transitions between two possible equilibria of the temperature inversion. The simulations show such noise-induced regime transitions, successfully identified by the indicator. The indicator is further applied to time series data from nocturnal and polar meteorological measurements.
Programme: 1013
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Florence Piette, Caroline Struvay, Georges Feller. (2011). The protein folding challenge in psychrophiles: facts and current issues (Vol. 13).
Abstract: The protein folding process in psychrophiles is impaired by low temperature, which exerts several physicochemical constraints, such as a decrease in the folding rate, reduced molecular diffusion rates and increased solvent viscosity, which interfere with conformational sampling. Furthermore, folding assistance is required at various folding steps according to the protein size. Recent studies in the field have provided contrasting and sometimes contradictory results, although protein folding generally appears as a rate-limiting step for the growth of psychrophiles. It is proposed here that these discrepancies reflect the diverse adaptive strategies adopted by psychrophiles in order to allow efficient protein folding at low temperature. Cold adaptations apparently superimpose on pre-existing cellular organization, resulting in different adaptive strategies. In addition, microbial lifestyle further modulates the properties of the chaperone machinery, which possibly explains the occurrence of cold-adapted and non-cold-adapted protein chaperones in psychrophiles.
Programme: 1074
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N. Ribeiro, L. Herraiz-Borreguero, S. R. Rintoul, C. R. McMahon, M. Hindell, R. Harcourt, G. Williams. (2021). Warm Modified Circumpolar Deep Water Intrusions Drive Ice Shelf Melt and Inhibit Dense Shelf Water Formation in Vincennes Bay, East Antarctica (Vol. 126).
Keywords: AABW Antarctic Coastal Circulation Antarctic Margins basal melt mCDW intrusions seal CTD
Programme: 109
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. (2021). Antarctic Atmospheric River Climatology and Precipitation Impacts (Vol. 126).
Keywords: Antarctica atmospheric rivers climatology meteorology
Programme: 411
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. (2021). Minute Sea-Level Analysis (MISELA): a high-frequency sea-level analysis global dataset (Vol. 13).
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. (2022). Seven snail species hidden in one: Biogeographic diversity in an apparently widespread periwinkle in the Southern Ocean (Vol. 49).
Keywords: Antarctic cryptic species dispersal Littorinidae species-delimitation analyses sub-Antarctic vicariance
Programme: 1044
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Piero Poli, Nikolai M. Shapiro. (2022). (Vol. 49).
Keywords: backprojection seismology source surface waves Tonga volcanology
Programme: 133
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V. Haberle, A. Marchaudon, A. Chambodut, P.-L. Blelly. (2022). Direct Determination of Geomagnetic Baselines During Quiet Periods for Low- and Mid-Latitude Observatories (Vol. 127).
Abstract: The geomagnetic field is composed of a variety of sources that act on a wide range of timescales and amplitudes. The separation of magnetic storm effects from quiet variations is needed to accurately quantify impacts of space weather events. The extraction of such quiet contributions within geomagnetic measurements is achieved by the determination of baselines, which, ideally, is done by a simple algorithm which captures quiet sources suitably well, while being applicable to an extensive network of magnetic observatories independent of the period of time. In this work, we apply signal filtering techniques on the horizontal components of geomagnetic field measurements from low- and mid-latitude observatories to determine baselines. The variations within the baseline are investigated for magnetically quiet periods between 1991 and 2019, focusing on long-term trends, seasonal and local time dependencies, and day-to-day variability. The analysis confirms that the contributing quiet sources include the secular variation and the solar quiet (Sq) current system. The non-negligible day-to-day variability, that is typical for Sq in low- and mid-latitudes, is embedded within the baseline. Thus, the filter approach extracts quiet magnetic field variations well. Comparisons with other baseline methods show good agreements. We conclude that the filter approach can be used to determine baselines automatically during magnetically quiet periods without the need of further apriori information and is applicable on a wide network of magnetic observatories. It marks the first step for deriving magnetic indices for (near) real-time space weather applications.
Keywords: magnetic baseline magnetic observatory data quiet geomagnetic field Sq current
Programme: 139
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. (2022). Every hooked beak is maintained by a prey: Ecological signal in cephalopod beak shape (Vol. 36).
Abstract: Beaks are among the few hard parts of coleoid cephalopods and are informative for species identification. Although mandible shape has been shown to be adaptive in many vertebrate taxa, it has been suggested that the shape of coleoid beaks does not bear any ecological signal. Yet, previous studies only explored beak shape in 2D and none have provided an in-depth investigation of the potential relationship with ecological variables such as habitat use or diet. The goal of the present study was to understand whether variation in cephalopod beak shape reflects ecology and/or is more driven by phylogenetic relatedness as suggested previously. We imaged 101 lower and 108 upper beaks in 3D using underwater photogrammetry and micro-CT scanning. Our 3D morphometric analysis conducted on 75 species of cephalopod shows that there is a significant but moderate phylogenetic signal. However, comparative phylogenetically informed analyses demonstrate that beak shape is also driven by ecology. We detected significant differences in beak shape between species inhabiting different habitats (pelagic, benthic or demersal) and of different trophic levels. Our results further suggest that beak shape variation can be summarized along a continuum between two main functions: fast closing versus hard biting. These results provide novel insights into the drivers of beak shape diversity in coleoid cephalopods and suggest that beak shape has evolved adaptively in relation to diet and habitat use. Read the free Plain Language Summary for this article on the Journal blog.
Keywords: 3D geometric morphometrics beak cephalopod ecology phylogenetic signal
Programme: 109
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