Easier detection of invertebrate "identification-key characters" with light of different wavelengths

The marine α-taxonomist often encounters two problems. Firstly, the "environmental dirt" that is frequently present on the specimens and secondly the difficulty in distinguishing key-features due to the uniform colours which fixed animals often adopt

First and repeated records of the tropical-temperate crab Asthenognathus atlanticus Monod, 1932 (Decapoda: Brachyura) in the eastern part of the Bay of Seine (eastern English Channel, France)

International audienceAsthenognathus atlanticus Monod, 1932, has been reported for the first time from the eastern part of the bay ofSeine (eastern english Channel). A total of 30 specimens were collected between the years 2008 and 2011, along thenormandy coast from ouistreham to Antifer, mainly on mud and muddy sand habitats, between 10 and 25 m depth. thedistribution range of A. atlanticus has been previously known to cover eastern Atlantic coasts from Angola to the westernenglish Channel, where it reached its northern limits. it is also present in the western part of the Mediterranean Sea. thechanges in the sediment composition of the eastern bay of Seine have probably led to the development of a potentiallyfavorable habitat for this species. However, the data collected have not yet been sufficient to ascertain the origin, and themethod of introduction of the eastern english Channel specimens. in the discussion, we ponder if they might haveoriginated from the western english Channel populations, and was transported as larvae in the eastern english Channel;they could have originated from a more distant population, and have been brought to the eastern english Channel throughhuman activities. each hypothesis is possible in theory

Maerl grounds : habitats of high biodiversity in European seas

The BIOMAERL programme is a 3-year collaborative programme between laboratories in UK, Spain, France and Malta which began in February 1996. Its main plans are described in the workplan. A full inventory of the biological composition (biodiversity) of maerl bed assemblages in these regions therefore has yet to be completed, but progress is outlined below.peer-reviewe

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

Solar Winds Driven by Nonlinear Low-Frequency Alfven Waves from the Photosphere : Parametric Study for Fast/Slow Winds and Disappearance of Solar Winds

(abridged) We investigate how the properties of the corona and solar wind in the open coronal holes depend on the properties of the magnetic fields and their footpoint motions at the surface, by perfoming 1D MHD simulations from the photosphere to 0.3 or 0.1AU. We impose low-frequency (<0.05Hz) transverse fluctuations of the field lines at the photosphere with various amplitude, spectrum, and polarization in the open flux tubes with different photospheric field strength, B, and super-radial expansion of the cross section, f_max. We find that a transonic solar wind is the universal consequence. The atmosphere is also stably heated up to >10^6K by the dissipation of the Alfven waves through compressive-wave generation and wave reflection in the case of the sufficient wave input with photospheric amplitude, > 0.7km/s. The density, and accordingly the mass flux, of solar winds show a quite sensitive dependence on because of an unstable aspect of the heating by the nonlinear Alfven waves. A case with =0.4km/s gives ~50 times smaller mass flux than the fiducial case for the fast wind with =0.7km/s; solar wind almost disappears only if becomes half. We also find that the solar wind speed has a positive correlation with B/f_max, which is consistent with recent observations. We finally show that both fast and slow solar winds can be explained by the single process, the dissipation of the low-frequency Alfven waves, with different sets of and B/f_max. Our simulations naturally explain the observed (i) anticorrelation of the solar wind speed and the coronal temperature and (ii) larger amplitude of the Alfvenic fluctuations in the fast winds. In Appendix, we also explain our implementation of the outgoing boundary condition of the MHD waves with some numerical tests.Comment: 27 pages, 16 figures embedded, accepted for publication in J. Geophys. Re

Effets biogènes sur la sédimentation en baie de Concarneau

Long-term monitoring of communities in the bay of Concarneau allows to describe the differents stages of succession, explained by biotic interactions between trophic groups. The tubicolous amphipod Haploops tubicola actively participated to consolidation and thickening of the muds. Biological changes are linked with general eutrophication of coastal environment and with trawling prohibition from 1974.Le suivi à long terme des peuplements de la baie de Concarneau montre les différentes étapes de la dynamique successionnelle décrites grâce aux mécanismes intervenant entre les différentes catégories trophiques. Le développement de l’amphipode tubicole Haploops tubicola a participé à l’exhaussement de la vasière en stabilisant le sédiment. Ceci en réponse à l’eutrophisation générale du milieu côtier, mais aussi à l’arrêt des chalutages dans cette baie depuis 1974.Glémarec Michel, Grall Jacques. Effets biogènes sur la sédimentation en baie de Concarneau. In: Cahiers Nantais, n°59, 2003. Comprendre et gérer la nature littorale. pp. 123-130