Impact of the 26-30 May 2003 solar events on the earth ionosphere and thermosphere.

During the last week of May 2003, the solar active region AR 10365 produced a large number of flares, several of which were accompanied by Coronal Mass Ejections (CME). Specifically on 27 and 28 May three halo CMEs were observed which had a significant impact on geospace. On 29 May, upon their arrival at the L1 point, in front of the Earth's magnetosphere, two interplanetary shocks and two additional solar wind pressure pulses were recorded by the ACE spacecraft. The interplanetary magnetic field data showed the clear signature of a magnetic cloud passing ACE. In the wake of the successive increases in solar wind pressure, the magnetosphere became strongly compressed and the sub-solar magnetopause moved inside five Earth radii. At low altitudes the increased energy input to the magnetosphere was responsible for a substantial enhancement of Region-1 field-aligned currents. The ionospheric Hall currents also intensified and the entire high-latitude current system moved equatorward by about 10°. Several substorms occurred during this period, some of them - but not all - apparently triggered by the solar wind pressure pulses. The storm's most notable consequences on geospace, including space weather effects, were (1) the expansion of the auroral oval, and aurorae seen at mid latitudes, (2) the significant modification of the total electron content in the sunlight high-latitude ionosphere, (3) the perturbation of radio-wave propagation manifested by HF blackouts and increased GPS signal scintillation, and (4) the heating of the thermosphere, causing increased satellite drag. We discuss the reasons why the May 2003 storm is less intense than the October-November 2003 storms, although several indicators reach similar intensities

Offspring sex ratio in relation to parental structural size and body condition in the long-lived wandering albatross (Diomedea exulans)

International audienceSex ratio theory is one of the most controversial topics in evolutionary ecology. Many deviations from an equal production of males and females are reported in the literature, but few patterns appear to hold across species or populations. There is clearly a need to identify fitness effects of sex ratio variation. We studied this aspect in a population of a long-lived seabird, the wandering albatross (Diomedea exulans), using molecular sex-identification techniques. We report that parental traits affect both (1) fledgling traits in a sex-dependent way and (2) chick sex: Sons are overproduced when likely to be large at fledging and, to a lesser extent, daughters are overproduced when likely to be in good body condition at fledging. Because for the same population, a previous study reported that postfledging survival was positively affected by size in males and by body condition in females, our results suggest that wandering albatrosses manipulate offspring sex to increase post-fledging survival

Monitoring prey availability via data loggers deployed on seabirds: advances and present limitations

Seabirds constitute a key group of marine top-predators. While foraging seabirds prey mostly on schooling pelagic fish, crustaceans and squids. Because seabirds distribute over a wide spatial range they are sensitive to physical and biotic changes at several temporal scales. In the last 20 years bio-logging science has revolutionized our knowledge of how seabirds can act as monitors of prey stocks. One of the most interesting applications of data loggers on seabirds is determination of the distribution and availability of prey on which we have little knowledge such as mesopelagic fish, squid, and krill. There are now known to be several variables measurable by data loggers which estimate the number of prey caught by free-ranging seabirds. Such data loggers, in combined deployment on seabirds with time-depth or movement loggers (which record acceleration in one or more dimensions) provide data sets representing dependable indices of prey availability. While knowledge of seabird behaviour continues to improve, we still know little about the relationships between seabird behaviour and prey density/availability. Unravelling these relationships is a key step to calibrating the proxies of prey availability recorded by data loggers. Continuing to develop the use of instrumented seabirds as bio-indicators of marine resources is important in the quest to understand marine ecosystems and the conservation of top-predators