Schmidt, A.; Alard, F.; Handrich, Y. (2006). Changes in body temperatures in king penguins at sea: the result of fine adjustments in peripheral heat loss? Am. J. Physiol. Regul. Integr. Comp. Physiol., 291(3), R608–618.
Abstract: To investigate thermoregulatory adjustments at sea, body temperatures (the pectoral muscle and the brood patch) and diving behavior were monitored during a foraging trip of several days at sea in six breeding king penguins Aptenodytes patagonicus. During inactive phases at sea (water temperature: 4-7{degrees}C), all tissues measured were maintained at normothermic temperatures. The brood patch temperature was maintained at the same values as those measured when brooding on shore (38{degrees}C). This high temperature difference causes a significant loss of heat. We hypothesize that high-energy expenditure associated with elevated peripheral temperature when resting at sea is the thermoregulatory cost that a postabsorptive penguin has to face for the restoration of its subcutaneous body fat. During diving, mean pectoral temperature was 37.6 {+/-} 1.6{degrees}C. While being almost normothermic on average, the temperature of the pectoral muscle was still significantly lower than during inactivity in five out of the six birds and underwent temperature drops of up to 5.5{degrees}C. Mean brood patch temperature was 29.6 {+/-} 2.5{degrees}C during diving, and temperature decreases of up to 21.6{degrees}C were recorded. Interestingly, we observed episodes of brood patch warming during the descent to depth, suggesting that, in some cases, king penguins may perform active thermolysis using the brood patch. It is hypothesized that functional pectoral temperature may be regulated through peripheral adjustments in blood perfusion. These two paradoxical features, i.e., lower temperature of deep tissues during activity and normothermic peripheral tissues while inactive, may highlight the key to the energetics of this diving endotherm while foraging at sea.
Programme: 394
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Sciare, J.; Baboukas, E.; Kanakidou, M.; Krischke, U.; Belviso, S.; Bardouki, H.; Mihalopoulos, N. (2000). Spatial and temporal variability of atmospheric sulfur-containing gases and particles during the Albatross campaign. J. Geophys. Res., 105.
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. (2019). Plumage microbiota covaries with the major histocompatibility complex in blue petrels (Vol. 28).
Abstract: To increase fitness, a wide range of vertebrates preferentially mate with partners that are dissimilar at the major histocompatibility complex (MHC) or that have high MHC diversity. Although MHC often can be assessed through olfactory cues, the mechanism by which MHC genes influence odour remains largely unclear. MHC class IIB molecules, which enable recognition and elimination of extracellular bacteria, have been suggested to influence odour indirectly by shaping odour-producing microbiota, i.e. bacterial communities. However, there is little evidence of the predicted covariation between an animal's MHC genotype and its bacterial communities in scent-producing body surfaces. Here, using high-throughput sequencing, we tested the covariation between MHC class IIB genotypes and feather microbiota in the blue petrel (Halobaena caerulea), a seabird with highly developed olfaction that has been suggested to rely on oduor cues during an MHC-based mate choice. First, we show that individuals with similar MHC class IIB profiles also have similar bacterial assemblages in their feathers. Then, we show that individuals with high MHC diversity have less diverse feather microbiota and also a reduced abundance of a bacterium of the genus Arsenophonus, a genus in which some species are symbionts of avian ectoparasites. Our results, showing that feather microbiota covary with MHC, are consistent with the hypothesis that individual MHC genotype may shape the semiochemical-producing microbiota in birds.
Keywords: bacteria feathers MHC microbiome seabirds uropygial gland
Programme: 354
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. (2002). Measurement of the specific surface area of 176 snow samples using methane adsorption at 77 K. J. Geophys. Res., 107.
Keywords: 1863 Hydrology: Snow and ice; 3947 Mineral Physics: Surfaces and interfaces; 0399 Atmospheric Composition and Structure: General or miscellaneous; 0320 Atmospheric Composition and Structure: Cloud physics and chemistry
Programme: 437
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Preunkert, S.; Jourdain, B.; Legrand, M.; Udisti, R.; Becagli, S.; Cerri, O. (2008). Seasonality of sulfur species (dimethyl sulfide, sulfate, and methanesulfonate) in Antarctica: Inland versus coastal regions. J. Geophys. Res., 113, D15302.
Keywords: sulfur cycle; DMS; 0365 Atmospheric Composition and Structure: Troposphere: composition and chemistry; 0315 Atmospheric Composition and Structure: Biosphere/atmosphere interactions; 0305 Atmospheric Composition and Structure: Aerosols and particles
Programme: 414;903;1181
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A. Barbero, J. Savarino, R. Grilli, C. Blouzon, G. Picard, M. M. Frey, Y. Huang, N. Caillon. (2021). New Estimation of the NOx Snow-Source on the Antarctic Plateau (Vol. 126).
Keywords: Antarctic Plateau flux chamber nitrate photolysis snowpack emissions
Programme: 1177
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Collins T., Meuwis M.A, Gerday C. & Feller G. (2003). Activity, stability and flexibility in glycosisases adapted to extreme thermal environments. J. Mol. Biol., 328(2), 419–428.
Abstract: To elucidate the strategy of low temperature adaptation for a cold-adapted family 8 xylanase, the thermal and chemical stabilities, thermal inactivation, thermodependence of activity and conformational flexibility, as well as the thermodynamic basis of these processes, were compared with those of a thermophilic homolog. Differential scanning calorimetry, fluorescence monitoring of guanidine hydrochloride unfolding and fluorescence quenching were used, among other techniques, to show that the cold-adapted enzyme is characterized by a high activity at low temperatures, a poor stability and a high flexibility. In contrast, the thermophilic enzyme is shown to have a reduced low temperature activity, high stability and a reduced flexibility. These findings agree with the hypothesis that cold-adapted enzymes overcome the quandary imposed by low temperature environments via a global or local increase in the flexibility of their molecular edifice, with this in turn leading to a reduced stability. Analysis of the guanidine hydrochloride unfolding, as well as the thermodynamic parameters of irreversible thermal unfolding and thermal inactivation shows that the driving force for this denaturation and inactivation is a large entropy change while a low enthalpy change is implicated in the low temperature activity. A reduced number of salt-bridges are believed to be responsible for both these effects. Guanidine hydrochloride unfolding studies also indicate that both family 8 enzymes unfold via an intermediate prone to aggregation.
Programme: 193
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Sofikitis, A. M., Colin, J. L., Desboeufs, K. V., Losno, R. (2004). Iron analysis in atmospheric water samples by atomic absorption spectrmetry (AAS) in water-methanol. Analytical and bioanalytical chemistry, 378(2), 460–464.
Abstract: To distinguish between Fe(II) and Fe(III) species in atmospheric water samples, we have adapted an analytical procedure based on the formation of a specific complex between Fe(II) and ferrozine (FZ) on a chromatographic column. After elution of Fe(III), the Fe(II) complex is recovered with water-methanol (4:1). The possibility of trace iron measurements in this complex medium by graphite-furnace atomic-absorption spectrometry has been investigated. A simplex optimization routine was required to complete the development of the analytical method.
Programme: 1026
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. (2015). Comprehensive laboratory and field testing of cavity ring-down spectroscopy analyzers measuring H2O, CO2, CH4 and CO
. Atmospheric Measurement Techniques Discussions, 8(4), 4219–4272.
Abstract: To develop an accurate measurement network of greenhouse gases, instruments in the field need to be stable and precise and thus require infrequent calibrations and a low consumption of consumables. For about ten years, cavity ring-down spectroscopy (CRDS) analyzers have been available that meet these stringent requirements for precision and stability. Here, we present the results of tests of CRDS instruments in the laboratory (47 instruments) and in the field (15 instruments). The precision and stability of the measurements are studied. We demonstrate that, thanks to rigorous testing, newer models generally perform better than older models, especially in terms of reproducibility between instruments. In the field, we see the importance of individual diagnostics during the installation phase, and we show the value of calibration and target gases that assess the quality of the data. Finally, we formulate recommendations for use of these analyzers in the field.
Programme: 416
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. (2010). Experimental growth pattern calibration of Antarctic scallop shells (Adamussium colbecki, Smith 1902) to provide a biogenic archive of high-resolution records of environmental and climatic changes
. J. Exp. Mar. Biol. Ecol., 393(1-2), 158–167.
Abstract: To determine the potential of Antarctic bivalve shells as biomonitors for environmental and climatic variations in polar marine areas, we developed a growth model for juvenile Adamussium colbecki Smith, 1902 based on the use of in situ temporal calcein markings to calibrate growth patterns in the external striae formation. To minimize scallop stress caused by excessive handling, in situ benthic chambers were used for the marking experiment, during an exposure time of 6 h. Once marked, scallops remained on site in a benthic cage and were collected 18, 26, and 41 days later. Apart from a few specimens affected by possible calcein toxicity effects, the detectable mark in all shells revealed a higher austral summer growth rate for A. colbecki compared to other Antarctic bivalves. Using calcein labeling, we identified a near 14-day periodicity in the striae formation associated with the fortnightly seawater level regime. Striae counting and increment width measurements showed an annual cycle, with no clear cessation of growth in juvenile specimens, allowing age determination. Because of the relatively high growth rate for a polar species and easily recognizable sclerochronological calendar in the shell striae formation, A. colbecki is an appropriate species for high-resolution (infra-monthly) geochemical sampling. Comparison between LA-ICP-MS analyses (Li, B, Mg, Mn, Co, Sr, Ba, Pb) from one shell and hydrological parameters (sea level, temperature, salinity) measured in seawater suggests, however, that more work is needed to calibrate the trace element proxies. Nevertheless, the shell of the Antarctic scallop A. colbecki has tremendous potential for recording environmental conditions from time periods covering months to a few years in polar waters, notably the ice melting date.
Keywords: biology microbiology, ecology environment, marine sciences, meteorology climatology,
Programme: 688
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