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Author |
Mardon Jérôme, Saunders Sandra M, Bonadonna Francesco, |
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Title |
From preen secretions to plumage: the chemical trajectory of blue petrels' Halobaena caerulea social scent
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Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Avian Biology |
Abbreviated Journal |
0908-8857 |
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Volume |
42 |
Issue |
1 |
Pages |
29-38 |
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Keywords |
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Abstract |
Petrel seabirds heavily rely on their olfactory sense and are thus appropriate models for the study of avian chemical communication. The uropygial secretions of blue petrels Halobaena caerulea, for instance, have been shown to encapsulate elaborate sociochemical information including species, gender and identity. Yet, it is the plumage, and not preening secretions per se, which acts as the final substrate of avian scents. Importantly, the chemical relationship between secretions from the uropygial gland, located at the dorsal base of the tail, and plumage lipids has been considered in only a handful of studies which reported large qualitative differences. The emission process of avian scents, and the possible participation of the uropygial gland in particular, are therefore not elucidated. In the present study, we examine the early chemical trajectory of blue petrels' social chemosignals by comparing secretion and feather samples using Gas-Chromatography Mass-Spectrometry (GC/MS) and recently developed multivariate statistics. Our results indicate that (1) 85% of the feather lipids come from the uropygial secretions, (2) chemical differentiation between secretions and feather lipids includes qualitative and quantitative variations, which both have interesting implications for scent production, (3) the sociochemical information contained within the secretions (i.e. a sex-specific signal and individual chemical signatures) are present in very conserved forms on the plumage. In the light of these results, it is apparent that the uropygial gland plays a critical role for chemical communication in petrels and possibly other avian groups.
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354 |
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Blackwell Publishing Ltd |
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1600-048X |
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yes |
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Call Number |
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Serial |
3381 |
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Author |
Brodier S, Pisanu B, Villers A, Pettex E, Lioret M, Chapuis J-L, Bretagnolle V, |
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Title |
Responses of seabirds to the rabbit eradication on Ile Verte, sub-Antarctic Kerguelen Archipelago
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Type |
Journal Article |
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Year |
2011 |
Publication |
Animal Conservation |
Abbreviated Journal |
1367-9430 |
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Volume |
14 |
Issue |
5 |
Pages |
459-465 |
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Keywords |
Oryctolagus cuniculus, invasive mammal, burrowing petrels, brown skua, conservation program, Sub-Antarctic island, |
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Abstract |
Studies on the role of introduced rabbits, Oryctolagus cuniculus, on islands have mainly focused on their negative impacts on vegetation. However, little attention has been paid to their influence on vertebrate communities. On Ile Verte (148 ha) in the sub-Antarctic Kerguelen Archipelago, rabbits are the only mammal that have been introduced. The long-term consequences of their eradication in 1992 on both native, burrowing seabird prey populations and their predator, the brown skua Catharacta skua, were investigated between 1991 and 2005. Densities of breeding petrels were followed on site with three plant communities differing in their soil depth. In addition, the diet and breeding activities of skuas were evaluated on the entire island area. The density of breeding pairs of the most abundant petrel species, the blue petrel Halobaena caerulea, which only nested at the site with deep-soil, increased by approximately eightfold during the 6 years following the rabbit eradication. Of the other species nesting in deep soil, there was an approximately fourfold reduction in the Antarctic prion, Pachyptila desolata, but such a decrease in breeding pair densities was not observed in areas with shallow soils. The South-Georgian diving petrels, Pelecanoides georgicus, was the rarest species, nesting only on mineral soils, and for which breeding pairs did not vary through time. The total numbers of fledged chicks of skua on the island significantly increased during the study period, but not the total number of breeding pairs. Thus, brown skuas were not affected by the disappearance of rabbits and rather benefited from an increase of their preferred prey. Blue petrels recovered quickly to sites with deep-soil, benefiting from the rabbit eradication and the cessation of burrow disturbance. The decrease of Antarctic prions could have been the result of an exclusion process from nesting areas on the deep soil site by blue petrels.
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136 |
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Blackwell Publishing Ltd |
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ISSN |
1469-1795 |
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yes |
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Call Number |
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Serial |
3540 |
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Author |
Mémin A, Rogister Y, Hinderer J, Omang O C, Luck B, |
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Title |
Secular gravity variation at Svalbard (Norway) from ground observations and GRACE satellite data
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Type |
Journal Article |
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Year |
2011 |
Publication |
Geophysical Journal International |
Abbreviated Journal |
0956-540X |
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Volume |
184 |
Issue |
3 |
Pages |
1119-1130 |
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Keywords |
Satellite geodesy, Time variable gravity, Global change from geodesy, Arctic region, |
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Abstract |
The Svalbard archipelago, Norway, is affected by both the present-day ice melting (PDIM) and Glacial Isostatic Adjustment (GIA) subsequent to the Last Pleistocene deglaciation. The induced deformation of the Earth is observed by using different techniques. At the Geodetic Observatory in Ny-Ålesund, precise positioning measurements have been collected since 1991, a superconducting gravimeter (SG) has been installed in 1999, and six campaigns of absolute gravity (AG) measurements were performed between 1998 and 2007. Moreover, the Gravity Recovery and Climate Experiment (GRACE) satellite mission provides the time variation of the Earth gravity field since 2002. The goal of this paper is to estimate the present rate of ice melting by combining geodetic observations of the gravity variation and uplift rate with geophysical modelling of both the GIA and Earth's response to the PDIM. We estimate the secular gravity variation by superimposing the SG series with the six AG measurements. We collect published estimates of the vertical velocity based on GPS and VLBI data. We analyse the GRACE solutions provided by three groups (CSR, GFZ, GRGS). The crux of the problem lies in the separation of the contributions from the GIA and PDIM to the Earth's deformation. To account for the GIA, we compute the response of viscoelastic Earth models having different radial structures of mantle viscosity to the deglaciation histories included in the models ICE-3G or ICE-5G. To account for the effect of PDIM, we compute the deformation of an elastic Earth model for six models of ice-melting extension and rates. Errors in the gravity variation and vertical velocity are estimated by taking into account the measurement uncertainties and the variability of the GRACE solutions and GIA and PDIM models. The ground observations agree with models that involve a current ice loss of 25 km3 water equivalent yr1 over Svalbard, whereas the space observations give a value in the interval [5, 18] km3 water equivalent yr1. A better modelling of the PDIM, which would include the precise topography of the glaciers and altitude-dependency of ice melting, is necessary to decrease the discrepancy between the two estimates.
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337 |
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Blackwell Publishing Ltd |
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ISSN |
1365-246X |
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yes |
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Call Number |
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Serial |
3617 |
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Author |
Dietrich Muriel, Kempf Florent, Gómez-Díaz Elena, Kitaysky Alexander S, Hipfner J Mark, Boulinier Thierry, McCoy Karen D, |
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Title |
Inter-oceanic variation in patterns of host-associated divergence in a seabird ectoparasite
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Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of Biogeography |
Abbreviated Journal |
J. Biogeogr. |
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Volume |
39 |
Issue |
3 |
Pages |
545-555 |
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Keywords |
Co-evolution, host race, hostparasite interactions, Ixodes uriae, microsatellite, North Atlantic, North Pacific, tick, |
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Abstract |
Aim Parasites with global distributions and wide host spectra provide excellent models for exploring the factors that drive parasite diversification. Here, we tested the relative force of host and geography in shaping population structure of a widely distributed and common ectoparasite of colonial seabirds, the tick Ixodes uriae. Location Two natural geographic replicates of the system: numerous seabird colonies of the North Pacific and North Atlantic Ocean basins. Methods Using eight microsatellite markers and tick samples from a suite of multi-specific seabird colonies, we examined tick population structure in the North Pacific and compare patterns of diversity and structure to those in the Atlantic basin. Analyses included population genetic estimations of diversity and population differentiation, exploratory multivariate analyses, and Bayesian clustering approaches. These different analyses explicitly took into account both the geographic distance among colonies and host use by the tick. Results Overall, little geographic structure was observed among Pacific tick populations. However, host-related genetic differentiation was evident, but was variable among host types and lower than in the North Atlantic. Main conclusions Tick population structure is concordant with the genetic structure observed in seabird host species within each ocean basin, where seabird populations tend to be less structured in the North Pacific than in the North Atlantic. Reduced tick genetic structure in the North Pacific suggests that host movement among colonies, and thus tick dispersal, is higher in this region. In addition to information on parasite diversity and gene flow, our findings raise interesting questions about the subtle ways that host behaviour, distribution and phylogeographic history shape the genetics of associated parasites across geographic landscapes.
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333 |
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Blackwell Publishing Ltd |
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ISSN |
1365-2699 |
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yes |
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Call Number |
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Serial |
3776 |
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Author |
Gómez-Díaz Elena, Boulinier Thierry, Sertour Natacha, Cornet Muriel, Ferquel Elisabeth, McCoy Karen D, |
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Title |
Genetic structure of marine Borrelia garinii and population admixture with the terrestrial cycle of Lyme borreliosis
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Type |
Journal Article |
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Year |
2011 |
Publication |
Environmental Microbiology |
Abbreviated Journal |
Environ. Microbiol. |
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Volume |
13 |
Issue |
9 |
Pages |
2453-2467 |
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Keywords |
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Abstract |
Despite the importance of population structure for the epidemiology of pathogenic bacteria, the spatial and ecological heterogeneity of these populations is often poorly characterized. Here, we investigated the genetic diversity and population structure of the Lyme borreliosis (LB) spirochaete Borrelia garinii in its marine cycle involving colonial seabirds and different host races of the seabird tick Ixodes uriae. Multilocus sequence analyses (MLSA) on eight chromosomal and two plasmid loci (ospA and ospC) indicate that B. garinii circulating in the marine system is highly diverse. Microevolution in marine B. garinii seems to be mainly clonal, but recombination and selection do occur. Sequence types were not evenly distributed among geographic regions, with substantial population subdivision between Atlantic and Pacific Ocean basins. However, no geographic structuring was evident within regions. Results of selection analyses and phylogenetic discordance between chromosomal and plasmid loci indicate adaptive evolution is likely occurring in this system, but no pattern of host or vector-associated divergence was found. Recombination analyses showed evidence for population admixture between terrestrial and marine strains, suggesting that LB spirochaetes are exchanged between these enzootic cycles. Importantly, our results highlight the need to explicitly consider the marine system for a complete understanding of the evolutionary ecology and global epidemiology of Lyme borreliosis.
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333 |
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Publisher |
Blackwell Publishing Ltd |
Place of Publication |
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Edition |
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ISSN |
1462-2920 |
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Approved |
yes |
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Call Number |
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Serial |
3778 |
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Author |
Schimmel M, Stutzmann E, Gallart J, |
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Title |
Using instantaneous phase coherence for signal extraction from ambient noise data at a local to a global scale
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Type |
Journal Article |
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Year |
2011 |
Publication |
Geophysical Journal International |
Abbreviated Journal |
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Volume |
184 |
Issue |
1 |
Pages |
494-506 |
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Keywords |
Time series analysis, Interferometry, Body waves, Surface waves and free oscillations, |
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Abstract |
Stacks of ambient noise cross-correlations are more and more routinely used to extract empirical Green's functions between station pairs. The success of the cross-correlations is due to waves which are recorded by both stations and that constructively sum at lag times which equal their propagation time between the station pair. Stacking cross-correlograms corresponding to different time spans improves the azimuthal noise coverage and further enhances the signals. Here we show how the instantaneous phase coherence can be used for a more efficient signal extraction from ambient noise cross-correlations. The instantaneous phase coherence is obtained by analytic signal processing and can be employed through the phase cross-correlation and/or through the time-frequency domain phase-weighted stack. The phase cross-correlation is more sensitive to waveform similarity but less sensitive to strong amplitude features than the conventional cross-correlation. The time-frequency domain phase-weighted stack cleans the ambient noise cross-correlograms by attenuating incoherent noise and permits an improved signal identification. We show that both approaches are powerful tools in the recovery of signals from ambient noise data and show examples where they improve the extraction of P and Rayleigh waves by considering local and global scale applications.
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Programme |
133 |
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Publisher |
Blackwell Publishing Ltd |
Place of Publication |
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ISSN |
1365-246X |
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Approved |
yes |
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Call Number |
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Serial |
3792 |
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Author |
Ritsema J, Deuss A, van Heijst H J, Woodhouse J H, |
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Title |
S40RTS: a degree-40 shear-velocity model for the mantle from new Rayleigh wave dispersion, teleseismic traveltime and normal-mode splitting function measurements
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Type |
Journal Article |
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Year |
2011 |
Publication |
Geophysical Journal International |
Abbreviated Journal |
0956-540X |
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Volume |
184 |
Issue |
3 |
Pages |
1223-1236 |
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Keywords |
Composition of the mantle, Body waves, Surface waves and free oscillations, Seismic tomography, |
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Abstract |
We have developed model S40RTS of shear-velocity variation in Earth's mantle using a new collection of Rayleigh wave phase velocity, teleseismic body-wave traveltime and normal-mode splitting function measurements. This data set is an order of magnitude larger than used for S20RTS and includes new data types. The data are related to shear-velocity perturbations from the (anisotropic) PREM model via kernel functions and ray paths that are computed using PREM. Contributions to phase delays and traveltimes from the heterogeneous crust are estimated using model CRUST2.0. We calculate crustal traveltimes from long-period synthetic waveforms rather than using ray theory. Shear-velocity perturbations are parametrized by spherical harmonics up to degree 40 and by 21 vertical spline functions for a total of 35 301 degrees of freedom. S40RTS is characterised by 8000 resolved unknowns. Since we compute the exact inverse, it is straightforward to determine models associated with fewer or more unknowns by adjusting the model damping. S40RTS shares many characteristics with S20RTS because it is based on the same data types and similar modelling procedures. However, S40RTS shows more clearly than S20RTS the abrupt change in the pattern of shear-velocity heterogeneity across the 660-km phase transition and it presents a more complex patern of shear-velocity heterogeneity in the lower mantle. Utilities to visualise S40RTS and software to analyse the resolution of S40RTS (or models for different damping parameters) are made available.
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Programme |
133 |
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Publisher |
Blackwell Publishing Ltd |
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ISSN |
1365-246X |
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Approved |
yes |
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Call Number |
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Serial |
3793 |
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Author |
Leki V, Romanowicz B, |
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Title |
Inferring upper-mantle structure by full waveform tomography with the spectral element method
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Type |
Journal Article |
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Year |
2011 |
Publication |
Geophysical Journal International |
Abbreviated Journal |
0956-540X |
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Volume |
185 |
Issue |
2 |
Pages |
799-831 |
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Keywords |
Inverse theory, Surface waves and free oscillations, Seismic anisotropy, Seismic tomography, Computational seismology, Wave propagation, |
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Abstract |
Mapping the elastic and anelastic structure of the Earth's mantle is crucial for understanding the temperature, composition and dynamics of our planet. In the past quarter century, global tomography based on ray theory and first-order perturbation methods has imaged long-wavelength elastic velocity heterogeneities of the Earth's mantle. However, the approximate techniques upon which global tomographers have traditionally relied become inadequate when dealing with crustal structure, as well as short-wavelength or large amplitude mantle heterogeneity. The spectral element method, on the other hand, permits accurate calculation of wave propagation through highly heterogeneous structures, and is computationally economical when coupled with a normal mode solution and applied to a restricted region of the Earth such as the upper mantle (SEM). Importantly, SEM allows a dramatic improvement in accounting for the effects of crustal structure. Here, we develop and apply a new hybrid method of tomography, which allows us to leverage the accuracy of SEM to model fundamental and higher-mode long period (>60 s) waveforms. We then present the first global model of upper-mantle velocity and radial anisotropy developed using SEM. Our model, SEMum, confirms that the long-wavelength mantle structure imaged using approximate semi-analytic techniques is robust and representative of the Earth's true structure. Furthermore, it reveals structures in the upper mantle that were not clearly seen in previous global tomographic models. We show that SEMum favourably compares to and rivals the resolving power of continental-scale studies. This new hybrid approach to tomography can be applied to a larger and higher-frequency data set in order to gain new insights into the structure of the lower mantle and more robustly map seismic structure at the regional and smaller scales.
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Programme |
133 |
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Publisher |
Blackwell Publishing Ltd |
Place of Publication |
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ISSN |
1365-246X |
ISBN |
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yes |
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Call Number |
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Serial |
3794 |
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Author |
Rains Derek, Weimerskirch Henri, Burg Theresa M, |
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Title |
Piecing together the global population puzzle of wandering albatrosses: genetic analysis of the Amsterdam albatross Diomedea amsterdamensis
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Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Avian Biology |
Abbreviated Journal |
0908-8857 |
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Volume |
42 |
Issue |
1 |
Pages |
69-79 |
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Keywords |
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Abstract |
Wandering albatrosses have been subjected to numerous taxonomic revisions due to discoveries of new species, analyses of morphological data and, more recently, the inclusion of genetic data. The small population of albatrosses (170 individuals including 26 pairs breeding annually) on Amsterdam Island in the Indian Ocean, Diomedea amsterdamensis, has been given species status based on plumage and morphometrics, but genetic data published to date provide weak support and its specific status remains controversial for some authors. We used mitochondrial control region sequence data to elucidate the relationship of the Amsterdam albatross within the wandering albatross complex (Diomedea amsterdamensis, D. antipodensis, D. dabbenena and D. exulans). Three novel haplotypes were present in 35 individuals from Amsterdam Island, and were highly divergent (3.67.3%) from haplotypes found in the other three members of the wandering albatross complex. Low levels of genetic variation in Amsterdam albatross likely resulted, at least in part, from a population bottleneck. Geographic isolation in the wandering albatross complex is maintained by high natal philopatry. As Amsterdam Island is the only breeding ground for this critically endangered species, we strongly urge conservation efforts in the area, especially in relation to long line fisheries and other threats such as disease and introduced predators, and it be listed as a distinct species.
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Programme |
109 |
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Publisher |
Blackwell Publishing Ltd |
Place of Publication |
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Language |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1600-048X |
ISBN |
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Medium |
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Notes |
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Approved |
yes |
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Call Number |
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Serial |
1016 |
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Author |
Verrier Delphine, Guinet Christophe, Authier Matthieu, Tremblay Yann, Shaffer Scott, Costa Daniel P, Groscolas René, Arnould John PY, |
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Title |
The ontogeny of diving abilities in subantarctic fur seal pups: developmental trade-off in response to extreme fasting?
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Type |
Journal Article |
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Year |
2011 |
Publication |
Functional Ecology |
Abbreviated Journal |
0269-8463 |
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Volume |
25 |
Issue |
4 |
Pages |
818-828 |
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Keywords |
aerobic dive limit, behavioural plasticity, diving behaviour, diving physiology, growth strategy, myoglobin, oxygen stores, weaning, |
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Abstract |
1.A major hypothesis of life-history theory is that conditions of early development affect future survival and reproductive success. Responses to detrimental environments during early ontogeny may involve trade-offs between current and future fitness. Yet, the functional mechanisms involved in such evolutionary trade-offs remain poorly documented. 2.The physiological and behavioural ontogeny of diving abilities was examined in subantarctic fur seal (Arctocephalus tropicalis Gray) pups to assess whether the repeated extreme fasts they naturally endure throughout the period of maternal dependence impacts on their development. 3.The ontogeny of pup body oxygen storage capacity was slow, in particular for the muscle compartment, which shows limited increase in myoglobin content (0·230·85 g 100 g wet muscle1). As a consequence, by the time of weaning, mass-specific oxygen stores had only reached 76%, 24% and 61% of adult female capacity for blood, muscle and total, respectively. Concomitantly, in marked contrast to other pinniped infants, they spent decreasing amounts of time in water (167%) with age and exhibited very little diving experience and skills. 4.Overall, in addition to experiencing the longest fasting durations throughout the maternal dependence period, subantarctic fur seal pups demonstrate the lowest levels of mass-specific total oxygen stores and maximum dive duration of any otariid near the age of weaning reported to date. 5.Furthermore, dives that exceeded the calculated aerobic dive limit occurred with a very low frequency (0·04%), suggesting that behavioural limitations linked to the necessity to conserve energy to survive repeated fasting, rather than restricted oxygen storage capacity, constrained pup diving behaviour. 6.Hence, these animals appear to trade-off the early development of both their physiological and behavioural diving abilities in favour of body fat accumulation to survive the prolonged fasts they must endure and, potentially, provide a nutritional buffer while they locate appropriate food patches after weaning. While promoting pre-weaning survival, this strategy renders pups more vulnerable to unpredictable changes in environmental conditions and food availability at the transition to independent foraging and, thus, could have negative impact on post-weaning survival.
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Blackwell Publishing Ltd |
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1365-2435 |
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yes |
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1030 |
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