Abstract: Pasteurella multocida is one of the major causes of mass mortalities in wild birds. Here, we report the complete genome sequences of two P. multocida isolates from wild populations of two endangered seabird species, the Indian yellow-nosed albatrosses (Thalassarche carteri) and the northern rockhopper penguins (Eudyptes moseleyi).

Abstract: The Antarctic atmosphere is rapidly changing, but there are few observations available in the interior of the continent to quantify this change due to few ground stations and satellite measurements. The Concordia station is located on the East Antarctic Plateau (75° S, 123° E, 3233 m above mean sea level), one of the driest and coldest places on Earth. Several remote sensing instruments are available at the station to probe the atmosphere, together with operational meteorological sensors. In order to observe in situ clouds, temperature, relative humidity and supercooled liquid water (SLW) at a high vertical resolution, a new project based on the use of an unmanned aerial vehicle (drone) vertical take-off and landing from the DeltaQuad Company has been set up at Concordia. A standard Vaisala pressure, temperature and relative humidity sensor was installed aboard the drone coupled to an Anasphere SLW sensor. A total of thirteen flights were conducted from 24 December 2022 to 17 January 2023: nine technology flights and four science flights (on 2, 10, 11 and 13 January 2023). Drone-based temperature and relative humidity profiles were compared to (1) the balloon-borne meteorological observations at 12:00 UTC, (2) the ground-based microwave radiometer HAMSTRAD and (3) the outputs from the numerical weather prediction models ARPEGE and AROME. No SLW clouds were present during the period of observations. Despite technical issues with drone operation due to the harsh environments encountered (altitude, temperature and geomagnetic field), the drone-based observations were consistent with the balloon-borne observations of temperature and relative humidity. The radiometer showed a systematic negative bias in temperature of 2 °C, and the two models were, in the lowermost troposphere, systematically warmer (by 2–4 °C) and moister (by 10–30%) than the drone-based observations. Our study shows the great potential of a drone to probe the Antarctic atmosphere in situ at very high vertical resolution (a few meters).

Abstract: Our understanding of how microbiome signatures are modulated in wild fish populations remains poorly developed and has, until now, mostly been inferred from studies in commercial and farmed fish populations. Here, for the first time, we have studied changes in the skin and blood microbiomes of the Salmo trutta population of the volcanic Kerguelen archipelago located at the northern limit of the Antarctic Ocean. The Kerguelen Islands present a natural framework of population expansion and reveal a likely situation representing further climate change in distribution areas. Our results showed that S. trutta of the Kerguelen Islands has a microbiome signature distinct from those of salmonids of the Northern Hemisphere. Our study also revealed that the skin and blood microbiomes differ between sedentary and migratory S. trutta. While 18 phyla were shared between both groups of trout, independent of the compartment, 6 phyla were unique to migratory trout. Further analyses showed that microbiome signatures undergo significant site-specific variations that correlate, in some cases, with the peculiarity of specific ecosystems. Our study also revealed the presence of potential pathogens at particular sites and the impact of abiotic factors on the microbiome, most notably due to the volcanic nature of the environment. This study contributes to a better understanding of the factors that modulate the microbiome signatures of migratory and sedentary fish populations. It will also help to better monitor the impacts of climate change on the colonization process in the sub-Antarctic region.

Abstract: With its imaged debris disk of dust, its evaporating exocomets, and an imaged giant planet, the young (~23 Myr) β Pictoris system is a unique proxy for detailed studies of planet formation processes as well as planet–disk interactions. Here, we study ten years of European Southern Observatory/High Accuracy Radial Velocity Planet Searcher (HARPS) high-resolution spectroscopic data of β Pictoris. After removing the radial velocity (RV) signals arising from the δ Scuti pulsations of the star, a ~1,200-d periodic signal remains, which, within our current knowledge, we can only attribute to a second planet in the system. The β Pic c mass is about nine times the mass of Jupiter; it orbits at ~2.7 au on an eccentric (e ~ 0.24) orbit. More RV data are needed to obtain more precise estimates of the properties of β Pic c. The current modelling of the planet’s properties and the dynamic of the whole system has to be reinvestigated in light of this detection.

Abstract: An unknown Pinnularia taxon was recorded during a survey of the limno-terrestrial diatom flora of some hot springs in the Val Travers area (Grande Terre, Iles Kerguelen, sub-Antarctic region). The morphology of the species was investigated using both light and scanning electron microscopy. Based on these results, the species could not be identified using the currently available literature and is therefore described as a new species: Pinnularia schoelynckiana sp. nov. The new species is characterized by rhombic-lanceolate valves, radiate, geniculate striae changing into strongly convergent near the apices and an undulating, lateral raphe. A detailed morphological comparison is made with similar Pinnularia species, described from the Antarctic Region and worldwide. Brief notes on the associated diatom flora and its ecology are added.