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Author Visser K, Trampert J, Kennett B L N,
Title Global anisotropic phase velocity maps for higher mode Love and Rayleigh waves Type Journal Article
Year 2008 Publication Geophysical Journal International Abbreviated Journal
Volume 172 Issue 3 Pages 1016-1032
Keywords Inverse theory, Surface waves and free oscillations, Seismic anisotropy, Seismic tomography,
Abstract It is well established that the Earth's uppermost mantle is anisotropic, but there are no clear observations of anisotropy in the deeper parts of the mantle. Surface waves are well suited to observe anisotropy since they carry information about both radial and azimuthal anisotropy. Fundamental mode surface waves, for commonly used periods up to 200 s, are sensitive to structure in the first few hundred kilometres, and therefore, do not provide information on anisotropy below. Higher mode surface waves have sensitivities that extend to and beyond the transition zone, and should thus give insight about azimuthal anisotropy at greater depths. We have measured higher mode Love and Rayleigh phase velocities using a model space search approach, which provides us with consistent relative uncertainties from measurement to measurement and from mode to mode. From these phase velocity measurements, we constructed global anisotropic phase velocity maps. Prior to inversion, we determine the optimum relative weighting for anisotropy. We present global azimuthal phase velocity maps for higher mode Rayleigh waves (up to the sixth higher mode) and Love waves (up to the fifth higher mode) with corresponding average model uncertainties. The anisotropy we derive is robust within the uncertainties for all modes. Given the ray theoretical sensitivity kernels of Rayleigh and Love wave modes, the source of anisotropy is complex, but mainly located in the asthenosphere and deeper. Our models show a good correspondence with other studies for the fundamental mode, but we have been able to achieve higher resolution.
Programme 133
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Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-246X ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 2813
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Author Frederiksen Morten, Moe Børge, Daunt Francis, Phillips Richard A, Barrett Robert T, Bogdanova Maria I, Boulinier Thierry, Chardine John W, Chastel Olivier, Chivers Lorraine S, Christensen-Dalsgaard Signe, Clément-Chastel Céline, Colhoun Kendrew, Freeman Robin, Gaston Anthony J, González-Solís Jacob, Goutte Aurélie, Grémillet David, Guilford Tim, Jensen Gitte H, Krasnov Yuri, Lorentsen Svein-Håkon, Mallory Mark L, Newell Mark, Olsen Bergur, Shaw Deryk, Steen Harald, Strøm Hallvard, Systad Geir H, Thórarinsson Thorkell L, Anker-Nilssen Tycho,
Title Multicolony tracking reveals the winter distribution of a pelagic seabird on an ocean basin scale Type Journal Article
Year 2011 Publication Diversity and Distributions Abbreviated Journal Divers. Distrib.
Volume Issue Pages no-no
Keywords Black-legged kittiwake, geolocation, migration, non-breeding ecology, North Atlantic, Rissa tridactyla,
Abstract Aim An understanding of the non-breeding distribution and ecology of migratory species is necessary for successful conservation. Many seabirds spend the non-breeding season far from land, and information on their distribution during this time is very limited. The black-legged kittiwake, Rissa tridactyla, is a widespread and numerous seabird in the North Atlantic and Pacific, but breeding populations throughout the Atlantic range have declined recently. To help understand the reasons for the declines, we tracked adults from colonies throughout the Atlantic range over the non-breeding season using light-based geolocation. Location North Atlantic. Methods Geolocation data loggers were deployed on breeding kittiwakes from 19 colonies in 2008 and 2009 and retrieved in 2009 and 2010. Data from 236 loggers were processed and plotted using GIS. Size and composition of wintering populations were estimated using information on breeding population size. Results Most tracked birds spent the winter in the West Atlantic, between Newfoundland and the Mid-Atlantic Ridge, including in offshore, deep-water areas. Some birds (mainly local breeders) wintered in the North Sea and west of the British Isles. There was a large overlap in winter distributions of birds from different colonies, and colonies closer to each other showed larger overlap. We estimated that 80% of the 4.5 million adult kittiwakes in the Atlantic wintered west of the Mid-Atlantic Ridge, with only birds from Ireland and western Britain staying mainly on the European side. Main conclusions The high degree of mixing in winter of kittiwakes breeding in various parts of the Atlantic range implies that the overall population could be sensitive to potentially deteriorating environmental conditions in the West Atlantic, e.g. owing to lack of food or pollution. Our approach to estimating the size and composition of wintering populations should contribute to improved management of birds faced with such challenges.
Programme 333
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Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1472-4642 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 2835
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Author Gilg Olivier, Sittler Benoît, Hanski Ilkka
Title Climate change and cyclic predatorprey population dynamics in the high Arctic Type Journal Article
Year 2009 Publication Global Change Biology Abbreviated Journal Glob Chang Biol
Volume 15 Issue 11 Pages 2634-2652
Keywords Alopex lagopus, Arctic community, climate change, cyclic dynamics, Dicrostonyx groenlandicus, Greenland, Mustela erminea, Nyctea scandiaca, predatorprey interaction, Stercorarius longicaudus,
Abstract The high Arctic has the world's simplest terrestrial vertebrate predatorprey community, with the collared lemming being the single main prey of four predators, the snowy owl, the Arctic fox, the long-tailed skua, and the stoat. Using a 20-year-long time series of population densities for the five species and a dynamic model that has been previously parameterized for northeast Greenland, we analyzed the population and community level consequences of the ongoing and predicted climate change. Species' responses to climate change are complex, because in addition to the direct effects of climate change, which vary depending on species' life histories, species are also affected indirectly due to, e.g., predatorprey interactions. The lemmingpredator community exemplifies these complications, yet a robust conclusion emerges from our modeling: in practically all likely scenarios of how climate change may influence the demography of the species, climate change increases the length of the lemming population cycle and decreases the maximum population densities. The latter change in particular is detrimental to the populations of the predators, which are adapted to make use of the years of the greatest prey abundance. Therefore, climate change will indirectly reduce the predators' reproductive success and population densities, and may ultimately lead to local extinction of some of the predator species. Based on these results, we conclude that the recent anomalous observations about lack of cyclic lemming dynamics in eastern Greenland may well be the first signs of a severe impact of climate change on the lemmingpredator communities in Greenland and elsewhere in the high Arctic.
Programme 1036
Campaign
Address
Corporate Author Thesis Bachelor's thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-2486 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 2841
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Author Ritsema J, Van Heijst H J, Woodhouse J H, Deuss A,
Title Long-period body wave traveltimes through the crust: implication for crustal corrections and seismic tomography Type Journal Article
Year 2009 Publication Geophysical Journal International Abbreviated Journal
Volume 179 Issue 2 Pages 1255-1261
Keywords Body waves, Seismic tomography, Wave propagation, Crustal structure,
Abstract The traveltimes of P and SH waves through the crust depend strongly on wave period. At periods longer than 1015 s, where traveltime measurements for indirect (e.g. surface reflected and core reflected) waves are typically made, the traveltimes are shorter than predicted by ray theory. Crustal corrections, often used in global mantle tomography to isolate the effects of the crust on teleseismic traveltimes, may have a complex frequency dependence and influence finite-frequency inversions. Crustal corrections for profiles of CRUST2.0 and the PREM reference model for the mantle may be several seconds larger or smaller than ray-theoretical values, depending on crustal thickness, crustal velocities and wave period. This variability is observed in the difference times between the seismic phases SS and S and between PP and P. It is therefore important to incorporate the effects of the crust on traveltimes in finite-frequency tomography, in order to take full advantage of the variable mantle sensitivity of body waves at different periods.
Programme 133
Campaign
Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-246X ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 2905
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Author Yano Tomoko, Tanimoto T, Rivera L,
Title The ZH ratio method for long-period seismic data: inversion for S-wave velocity structure Type Journal Article
Year 2009 Publication Geophysical Journal International Abbreviated Journal 0956-540X
Volume 179 Issue 1 Pages 413-424
Keywords Surface waves and free oscillations, Seismic tomography, Wave propagation,
Abstract The particle motion of surface waves, in addition to phase and group velocities, can provide useful information for S-wave velocity structure in the crust and upper mantle. In this study, we applied a new method to retrieve velocity structure using the ZH ratio, the ratio between vertical and horizontal surface amplitudes of Rayleigh waves. Analysing data from the GEOSCOPE network, we measured the ZH ratios for frequencies between 0.004 and 0.05 Hz (period between 20 and 250 s) and inverted them for S-wave velocity structure beneath each station. Our analysis showed that the resolving power of the ZH ratio is limited and final solutions display dependence on starting models; in particular, the depth of the Moho in the starting model is important in order to get reliable results. Thus, initial models for the inversion need to be carefully constructed. We chose PREM and CRUST2.0 in this study as a starting model for all but one station (ECH). The eigenvalue analysis of the least-squares problem that arises for each step of the iterative process shows a few dominant eigenvalues which explains the cause of the inversion's initial-model dependence. However, the ZH ratio is unique in having high sensitivity to near-surface structure and thus provides complementary information to phase and group velocities. Application of this method to GEOSCOPE data suggest that low velocity zones may exist beneath some stations near hotspots. Our tests with different starting models show that the models with low-velocity anomalies fit better to the ZH ratio data. Such low velocity zones are seen near Hawaii (station KIP), Crozet Island (CRZF) and Djibuti (ATD) but not near Reunion Island (RER). It is also found near Echery (ECH) which is in a geothermal area. However, this method has a tendency to produce spurious low velocity zones and resolution of the low velocity zones requires further careful study. We also performed simultaneous inversions for volumetric perturbation and discontinuity-depth perturbation. While its formulation and inversion were straightforward, there seemed to be a difficult trade-off problem between volumetric perturbation and discontinuity-depth perturbation.
Programme 133
Campaign
Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-246X ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 2922
Permanent link to this record
 

 
Author Ingels Jeroen, Vanreusel Ann, Brandt Angelika, Catarino Ana I, David Bruno, De Ridder Chantal, Dubois Philippe, Gooday Andrew J, Martin Patrick, Pasotti Francesca, Robert Henri,
Title Possible effects of global environmental changes on Antarctic benthos: a synthesis across five major taxa Type Journal Article
Year 2012 Publication Ecology and Evolution Abbreviated Journal
Volume 2 Issue 2 Pages 453-485
Keywords Amphipoda, Echinoidea, Foraminifera, global climate change, Isopoda, Nematoda, Southern Ocean, zoobenthos,
Abstract Because of the unique conditions that exist around the Antarctic continent, Southern Ocean (SO) ecosystems are very susceptible to the growing impact of global climate change and other anthropogenic influences. Consequently, there is an urgent need to understand how SO marine life will cope with expected future changes in the environment. Studies of Antarctic organisms have shown that individual species and higher taxa display different degrees of sensitivity to environmental shifts, making it difficult to predict overall community or ecosystem responses. This emphasizes the need for an improved understanding of the Antarctic benthic ecosystem response to global climate change using a multitaxon approach with consideration of different levels of biological organization. Here, we provide a synthesis of the ability of five important Antarctic benthic taxa (Foraminifera, Nematoda, Amphipoda, Isopoda, and Echinoidea) to cope with changes in the environment (temperature, pH, ice cover, ice scouring, food quantity, and quality) that are linked to climatic changes. Responses from individual to the taxon-specific community level to these drivers will vary with taxon but will include local species extinctions, invasions of warmer-water species, shifts in diversity, dominance, and trophic group composition, all with likely consequences for ecosystem functioning. Limitations in our current knowledge and understanding of climate change effects on the different levels are discussed.
Programme 1124
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Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2045-7758 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 4664
Permanent link to this record
 

 
Author Qin Yilong, Capdeville Yann, Montagner Jean-Paul, Boschi Lapo, Becker Thorsten W,
Title Reliability of mantle tomography models assessed by spectral element simulation Type Journal Article
Year 2009 Publication Geophysical Journal International Abbreviated Journal 0956-540X
Volume 177 Issue 1 Pages 125-144
Keywords Surface waves and free oscillations, Seismic tomography, Computational seismology,
Abstract Global tomographic models collected in the Seismic wave Propagation and Imaging in Complex (SPICE media: a European network) model library () share a similar pattern of long, spatial wavelength heterogeneity, but are not consistent at shorter spatial wavelengths. Here, we assess the performance of global tomographic models by comparing how well they fit seismic waveform observations, in particular Love and Rayleigh wave overtones and fundamental modes. We first used the coupled spectral element method (CSEM) to calculate long-period (>100 s) synthetic seismograms for different global tomography models. The CSEM can incorporate the effect of three-dimensional (3-D) variations in velocity, anisotropy, density and attenuation with very little numerical dispersion. We then compared quantitatively synthetic seismograms and real data. To restrict ourselves to high-quality overtone data, and to minimize the effects of the finite extent of seismic sources and of crustal heterogeneity, we favour deep (>500 km) earthquakes of intermediate magnitude (Mw7). Our comparisons reveal that: (1) The 3-D global tomographic models explain the data much better than the one-dimensional (1-D) anisotropic Preliminary Reference Earth Model (PREM). The current 3-D tomographic models have captured the large-scale features of upper-mantle heterogeneities, but there is still some room for the improvement of large-scale features of global tomographic models. (2) The average correlation coefficients for deep events are higher than those for shallow events, because crustal structure is too complex to be completely incorporated into CSEM simulations. (3) The average correlation coefficient (or the time lag) for the major-arc wave trains is lower (or higher) than that for the minor-arc wave trains. Therefore, the current tomographic models could be much improved by including the major-arc wave trains in the inversion. (4) The shallow-layer crustal correction has more effects on the fundamental surface waves than on the overtones.
Programme 133
Campaign
Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-246X ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 2928
Permanent link to this record
 

 
Author Pincemy Gwénaëlle, Dobson F Stephen, Jouventin Pierre,
Title Homosexual Mating Displays in Penguins Type Journal Article
Year 2010 Publication Ethology Abbreviated Journal
Volume 116 Issue 12 Pages 1210-1216
Keywords
Abstract More than 50 yr ago, field studies recorded the same-sex pairs (and trios) of penguins displaying to each other during the mating season, using behavior patterns typical of heterosexual mating displays. Such observations led to a hypothesis that due to a lack of sex recognition pairing occurs at random with respect to sex, an idea countered by the argument that sex recognition is highly accurate. No quantification of same-sex mating displays has tested the frequency of such displays in penguins or tested the hypothesis of random display partners with respect to sex. During their mating season, we studied displaying and paired king penguins, Apenodytes patagonicus, at Kerguelen Island and sexed them using a DNA marker, to quantify any occurrence of this behavior. Indeed, same-sex courtship displays were common (28.3% of 53 displaying pairs), the great majority of which were between males. Some homosexually displaying males eventually paired with females, but such males were significantly slower in heterosexual pairing than males that did not display homosexually. In two extraordinary cases, same-sex pairs learned each others calls, an essential step in the pairing process. The frequency of such pairs was much lower than among displaying couples, significantly so for males. Finally, the frequency of homosexually displaying pairs was significantly lower than expected from random assortment of displaying birds, for both males and females. We examined possible explanations for same-sex display and its biological significance. A population sex-ratio bias in favor of males and high concentration of male sex hormones may help to explain non-reproductive homosexually displaying pairs.
Programme 354
Campaign
Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1439-0310 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 3035
Permanent link to this record
 

 
Author ROLLAND VIRGINIE, WEIMERSKIRCH HENRI, BARBRAUD CHRISTOPHE,
Title Relative influence of fisheries and climate on the demography of four albatross species Type Journal Article
Year 2010 Publication Global Change Biology Abbreviated Journal Glob Chang Biol
Volume 16 Issue 7 Pages 1910-1922
Keywords breeding success, climate, longlining, seabird, survival,
Abstract Worldwide ecosystems are modified by human activities and climate change. To be able to predict future changes, it is necessary to understand their respective role on population dynamics. Among the most threatened species are top predators because of their position in the food web. Albatross populations are potentially affected by both human activities, especially longline fisheries, and climatic fluctuations. Based on long-term data (19852006), we conducted through a comparative approach a demographic analysis (adult survival and breeding success) on four albatross species breeding on the Indian Ocean sub-Antarctic Islands to assess the relative impact of climate and fisheries during and outside the breeding season. The study revealed that adult survival of almost all species was not affected by climate, and therefore probably canalized against climatic variations, but was negatively affected by tuna longlining effort in three species. Breeding success was affected by climate, with contrasted effects between species, with Southern Oscillation Index having an impact on all species but one. Differences in demographic responses depended on the foraging zone and season. In order to predict population trajectories of seabirds such as albatrosses, our results show the importance of assessing the relative influence of fishing and climate impacts on demography.
Programme 109
Campaign
Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1365-2486 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 3066
Permanent link to this record
 

 
Author Gilbert Caroline, McCafferty Dominic, Le Maho Yvon, Martrette Jean-Marc, Giroud Sylvain, Blanc Stéphane, Ancel André,
Title One for all and all for one: the energetic benefits of huddling in endotherms Type Journal Article
Year 2010 Publication Biological Reviews Abbreviated Journal
Volume 85 Issue 3 Pages 545-569
Keywords huddling, group, social behaviour, thermoregulation, energy conservation, ambient temperature, mammals, birds,
Abstract Huddling can be defined as an active and close aggregation of animals. It is a cooperative group behaviour, permitting individuals involved in social thermoregulation to minimize heat loss and thereby lower their energy expenditure, and possibly allowing them to reallocate the saved energy to other functions such as growth or reproduction. Huddling is especially important in the case of animals faced with high heat loss due to a high surface-to-volume ratio, poor insulation, or living in cold environments. Although numerous experimental studies have focused on the huddling behaviour of a wide range of species, to our knowledge, this is the first attempt to review the various implications of this widely used behavioural strategy. Huddling allows individuals to maximise energy savings by (1) decreasing their cold-exposed body surface area, (2) reducing their heat loss through warming of ambient temperatures surrounding the group, and (3) eventually lowering their body temperature through physiological processes. Huddling provides substantial energy savings and is estimated to reduce energy expenditure by between 6 and 53%. Broad variations in the energetic benefits of huddling depend on the number of individuals and species involved in huddles, the ambient temperatures to which individuals are exposed and the density of the aggregations. It has been shown that huddling individuals have increased survival, a lower food intake, a decreased body mass loss, increased growth rate, reduced water loss, and/or a more constant body temperature together with a significant reduction in metabolic rate. Though huddling has been studied widely, this review reveals the intricacies of this adaptive behaviour.
Programme 137
Campaign
Address
Corporate Author Thesis
Publisher (down) Blackwell Publishing Ltd Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1469-185X ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 3125
Permanent link to this record