|
Hughes Kevin A, Lee Jennifer E, Tsujimoto Megumu, Imura Satoshi, Bergstrom Dana M, Ware Chris, Lebouvier Marc, Huiskes Ad HL, Gremmen Niek JM, Frenot Yves, Bridge Paul D, Chown Steven L, . (2011). Food for thought: Risks of non-native species transfer to the Antarctic region with fresh produce
. Biological Conservation, 144(5), 1682–1689.
Abstract: To understand fully the risk of biological invasions, it is necessary to quantify propagule pressure along all introduction pathways. In the Antarctic region, importation of fresh produce is a potentially high risk, but as yet unquantified pathway. To address this knowledge gap, >11,250 fruit and vegetables sent to nine research stations in Antarctica and the sub-Antarctic islands, were examined for associated soil, invertebrates and microbial decomposition. Fifty-one food types were sourced from c. 130 locations dispersed across all six of the Earths inhabited continents. On average, 12% of food items had soil on their surface, 28% showed microbial infection resulting in rot and more than 56 invertebrates were recorded, mainly from leafy produce. Approximately 30% of identified fungi sampled from infected foods were not recorded previously from within the Antarctic region, although this may reflect limited knowledge of Antarctic fungal diversity. The number of non-native flying invertebrates caught within the Rothera Research Station food storage area was linked closely with the level of fresh food resupply by ship and aircraft. We conclude by presenting practical biosecurity measures to reduce the risk of non-native species introductions to Antarctica associated with fresh foods.
Keywords: Alien, Non-indigenous, Biosecurity, Propagules, Food, Polar, Antarctica, Sub-Antarctic,
Programme: 136
|
|
|
Renault D, . (2011). Sea water transport and submersion tolerance as dispersal strategies for the invasive ground beetle Merizodus soledadinus (Carabidae)
. 0722-4060, 34(10), 1591–1595.
Abstract: The alien ground beetle Merizodus soledadinus was introduced to the sub-Antarctic Kerguelen Islands in 1913. It colonized several small islands and islets of this archipelago, without any apparent human assistance in some locations, and crossed several large rivers and alluvial plains. As aggregations of this species on the tidal drift line are common at the Kerguelen Islands, the present work examined whether adult individuals of M. soledadinus could disperse by flotation on the sea. Different sample sizes of ground beetles (from 1 to 10) were placed on sea water at 8°C in plastic vials. Survival (50% lethal times) significantly increased from 2.1 ± 0.2 days for single beetles to 6.5 ± 0.3 days for groups of 10 beetles per vial, with there being no difference in the survival duration for groups of 2, 5, and 10 beetles per vial. Similar survival durations were found for beetles in vials with artificially agitated water and controls. In addition, the duration of survival was twice as high under freshwater versus sea water conditions, when groups of 10 adults were used. Finally, the survival to total submersion in freshwater was evaluated, and ranged from 3 to 4 days. This ability to survive extended periods both floating on and/or submerged beneath salt and freshwater conditions, indicates the presence of a successful dispersal mechanism, which may facilitate the dispersal range of M. soledadinus across the Kerguelen Islands, comprising over 300 islands and islets in total.
Keywords: Biomedical and Life Sciences,
Programme: 136
|
|
|
Klein K-L, Trottet G, Samwel S, Malandraki O, . (2011). Particle Acceleration and Propagation in Strong Flares without Major Solar Energetic Particle Events
. Solar Physics, 269(2), 309–333.
Abstract: Solar energetic particles (SEPs) detected in space are statistically associated with flares and coronal mass ejections (CMEs). But it is not clear how these processes actually contribute to the acceleration and transport of the particles. The present work addresses the question why flares accompanied by intense soft X-ray bursts may not produce SEPs detected by observations with the GOES spacecraft. We consider all X-class X-ray bursts between 1996 and 2006 from the western solar hemisphere. 21 out of 69 have no signature in GOES proton intensities above 10 MeV, despite being significant accelerators of electrons, as shown by their radio emission at cm wavelengths. The majority (11/20) has no type III radio bursts from electron beams escaping towards interplanetary space during the impulsive flare phase. Together with other radio properties, this indicates that the electrons accelerated during the impulsive flare phase remain confined in the low corona. This occurs in flares with and without a CME. Although GOES saw no protons above 10 MeV at geosynchronous orbit, energetic particles were detected in some (4/11) confined events at Lagrangian point L1 aboard ACE or SoHO. These events have, besides the confined microwave emission, dm-m wave type II and type IV bursts indicating an independent accelerator in the corona. Three of them are accompanied by CMEs. We conclude that the principal reason why major solar flares in the western hemisphere are not associated with SEPs is the confinement of particles accelerated in the impulsive phase. A coronal shock wave or the restructuring of the magnetically stressed corona, indicated by the type II and IV bursts, can explain the detection of SEPs when flare-accelerated particles do not reach open magnetic field lines. But the mere presence of these radio signatures, especially of a metric type II burst, is not a sufficient condition for a major SEP event.
Keywords: Physics and Astronomy,
Programme: 227
|
|
|
Schott Jean-Jacques, Thébault Erwan, . (2011). Modelling the earth's magnetic field from global to regional scales, in: Geomagnetic Observations and Models, IAGA Special Sopron Book Series (Vol. 5). Bachelor's thesis, Springer Netherlands, .
Abstract: In the recent years, a large amount of magnetic vector and scalar data have been measured or made available to scientists. They cover different ranges of altitudes from ground to satellite levels and have high horizontal densities over some geographical areas. Processing these potential field data may require alternatives to the widely used Spherical Harmonics. During the past decades, new techniques have been proposed to model regionally the magnetic measurements. They complement the set of older approaches that were revived and sometimes revised in the meantime. The amount of available techniques is intimidating and one often wonders which method is the most appropriate for what purpose. In this paper, we review several modelling strategies. Starting from the Spherical Harmonics, we discuss methods with global support (wavelets, multi-scale, Slepian functions,) and then bring the focus on regional methods with local support (Rectangular Harmonic Analysis, Cylindrical Harmonic Analysis, Spherical Caps,). We briefly examine the theoretical aspects and properties of each approach. We compare them with the help of a unique set of perfect synthetic data that mimic an ideal spatial distribution at a fixed surface. This helps us to better emphasize the theoretical characteristics of each approach and suggest, when relevant, improvements that would be useful for future practical applications.
Keywords: Earth and Environmental Science,
Programme: 139;905
|
|
|
A. Chambodut and M. Menvielle. (2011). From 1-minute to 1-second sampling interval at geomagnetic observatories: example of French magnetic observatories of Austral and Antarctic territories. Bachelor's thesis, , .
Abstract: IUGG 2011 Melbourne Australia.
Programme: 139;905
|
|
|
Landais A, Dreyfus G, Capron E, Pol K, Loutre M F, Raynaud D, Lipenkov V Y, Arnaud L, Masson-Delmotte V, Paillard D, Jouzel J, Leuenberger M, . (2011). Towards orbital dating of the EPICA Dome C ice core using dO2/N2. 1814-9324, 7(3), 2217–2259.
|
|
|
Johann Bourgeois . (2011). Croissance musculaire chez le poussin de manchot royal (Aptenodytes patagonicus) au cours de la période hivernale. Bachelor's thesis, , .
|
|
|
Schlichtholz P, Houssais M-N, . (2011). Forcing of oceanic heat anomalies by air-sea interactions in the Nordic Seas area
. 0148-0227, 116(C1), C01006–.
Abstract: Hydrographic data and atmospheric reanalysis from 1982 to 2005 are used to show a strong link of the Atlantic water temperature (AWT) anomalies observed in the transition zone between the Norwegian Atlantic current and the West Spitsbergen current in summer to the surface heat flux (SHF) anomalies observed over the Barents Sea open water in the preceding late winter. A mechanism proposed for this link is formation of ocean temperature anomalies in a deep mixed layer and their subsequent westward export by a branch of Atlantic water recirculating in the western Barents Sea. The SHF anomalies over the Barents Sea are due to advection of temperature and humidity by anomalous winds across the Arctic ice edge and do not strongly depend on the North Atlantic oscillation (NAO). Correlations of up to about 0.9 between the AWT anomalies and indices of atmospheric variability over the Barents Sea open prospects for seasonal AWT predictability. It is also shown that the wind-forcing responsible for positive AWT anomalies is involved in a cyclonic perturbation of the atmospheric circulation over the Nordic Seas. This perturbation generates, through influence on the sea ice distribution, a lobe of SHF anomalies in the marginal ice zone (MIZ) on the eastern (Barents Sea) and western (Greenland Sea) sides of the Nordic Seas which has the opposite sign to the open water lobe. In contrast to the Barents Sea MIZ, the diabatic heating of the atmosphere by upward SHF anomalies in the Greenland Sea MIZ competes with cold advection.
Keywords: Nordic Seas, heat anomalies, air-sea interactions, interanual variability, Atlantic water, 4215 Oceanography: General: Climate and interannual variability, 4504 Oceanography: Physical: Air/sea interactions, 4207 Oceanography: General: Arctic and Antarctic oceanography, 4263 Oceanography: General: Ocean predictability and prediction, 4572 Oceanography: Physical: Upper ocean and mixed layer processes,
Programme: 452
|
|
|
Houssais Marie-Nolle, Herbaut Christophe, . (2011). Atmospheric forcing on the Canadian Arctic Archipelago freshwater outflow and implications for the Labrador Sea variability
. 0148-0227, 116, C00D02–.
Abstract: The variability of the freshwater export through the Canadian Arctic Archipelago (CAA) is analyzed using a hindcast simulation forced by surface atmospheric forcing from the ERA40 reanalysis (1958–2001). Although the two channels representing the archipelago in the model are both sensitive to the along-channel sea surface height (SSH) gradient, they appear to have very distinct behaviors. The outflow to Lancaster Sound is shown to be largely controlled by the magnitude of the upstream SSH gradient across McClure Strait. The gradient shows a close link to the wind stress curl in the western Arctic but also to a large-scale SSH anomaly pattern which has a strong signal over the shelf to the south of McClure Strait. The latter has, however, little statistical connection to the SSH variability in the Beaufort Gyre. By contrast, the outflow through Nares Strait responds preferentially to SSH variations in the northern Baffin Bay which are remotely forced by air-sea heat exchanges in the Labrador Sea. The variability is largely coherent between the two outflows and is controlled by a dipolar atmospheric pattern reminiscent of the North Atlantic/Arctic Oscillation. When entering the subpolar gyre, the CAA freshwater outflow remains confined to the Labrador shelf with little impact on the salinity of the interior Labrador Sea and potentially on the convection. The latter is represented by a distinct mode of salinity variability in the western subpolar gyre which is rather influenced by the variability of the sea ice export through Fram Strait.
Keywords: Arctic Ocean, freshwater, North Atlantic Oscillation, 4207 Oceanography: General: Arctic and Antarctic oceanography, 4215 Oceanography: General: Climate and interannual variability, 4255 Oceanography: General: Numerical modeling,
Programme: 452
|
|
|
Lacarra M, Houssais M-N, Sultan E, Rintoul SR, Herbaut C, . (2011). Summer hydrography on the shelf off Terre Adélie/George V Land based on the ALBION and CEAMARC observations during the IPY
. Polar Science, 5(2), 88–103.
|
|