Abstract: This database includes over 7,100 georeferenced occurrence records of sea urchins (Echinodermata: Echinoidea) obtained from samples collected in the Southern Ocean (+180°W/+180°E; -35°/-78°S) during oceanographic cruises led over 150 years, from 1872 to 2015. Echinoids are common organisms of Southern Ocean benthic communities. A total of 201 species is recorded, which display contrasting depth ranges and distribution patterns across austral provinces and bioregions. Echinoid species show various ecological traits including different nutrition and reproductive strategies. Information on taxonomy, sampling sites, and sampling sources are also made available. Environmental descriptors that are relevant to echinoid ecology are also made available for the study area (-180°W/+180°E; -45°/-78°S) and for the following decades: 1955–1964, 1965–1974, 1975–1984, 1985–1994 and 1995–2012. They were compiled from different sources and transformed to the same grid cell resolution of 0.1° per pixel. We also provide future projections for environmental descriptors established based on the Bio-Oracle database (Tyberghein et al. 2012).

Abstract: We present the results of a study of the morphometric properties of a talus slope in subarctic Quebec (Nunavik) using field-based methods, including geomorphological, granulometric and plant distribution surveys, and statistical analyses. Slope processes are currently active, despite the limited altitudinal difference between the apical-to-distal parts of the slope and the imminent depletion of the debris supply. The near-rectilinear long profiles of the talus highlight the distribution of debris across the slope and demonstrate that free-fall of rock fragments is not the only process operating (redistribution is higher in the westernmost profile, which exhibits a clear concave shape). The spatial distribution of vegetation covering the screes highlights the recent age of parts of the talus, showing that present-day processes are still active, although limited. The short remaining apical rockwall highlights the shortage of debris following deglaciation, as debris are mostly supplied by freeze-thaw processes to the talus, and are then reworked by other processes which need to be better defined in subsequent research.

Abstract: Changes in mass, extent, duration, and physical properties of snow are key elements for studying associated climate change feedbacks in northern regions. In this study, we analyzed snowpack physical properties along a ‘mega’ transect from 47°N to 83°N (4,000 km) in northeastern Canada, which includes marked transitions between ecozones from boreal forest to subarctic and arctic ecosystems. Our unique dataset of 391 detailed snowpits acquired over the last 20 years, complemented with snow data from weather stations, shows that snowpack properties such as snow water equivalent, snow depth, density, grain size and basal depth hoar fraction (DHF) are strongly linked to vegetation type. Based on these results, we propose an updated classification of snow types in three classes: boreal forest snow (47–58°N), tundra snow (58–74°N) and polar desert snow (74–83°N), which is more appropriate to the study area than the general north hemisphere classification commonly used. We also show that shrub presence along the transect contributes to a significant increase in DHF development which contributes most strongly to the thermal insulation properties of the snowpack. Overall, our analysis suggests that snow–vegetation interactions have a positive feedback effect on warming at northern latitudes.

Abstract: The lichenized genus Steinera is revised for the archipelagos of Crozet and of Kerguelen, with a high level of endemism revealed. It is shown to represent a good example of convergent evolution between two different orders. Phylogenetic analyses using nuLSU, RPB1 and mtSSU sequences show that two different species groups can be recognized: Steinera s. str. belongs to the Arctomiaceae (Arctomiales) and is characterized notably by species having pluriseptate ascospores, and a second species group belongs to the Koerberiaceae (Peltigerales) and is characterized notably by simple ascospores sometimes having a plasma-bridge. The genus Henssenia is newly described to accommodate this latter group. The type species of Steinera is shown to have been erroneously treated in the past, with Steinera molybdoplaca being the type of Steinera and “S.” glaucella belonging to the genus Henssenia. A sorediate morph is recorded for S. molybdoplaca and the results confirmed using a 4-gene phylogeny, including nuITS sequences. Some species previously described in the genera Arctomia and Massalongia from the Southern Hemisphere are shown to belong to Steinera s. str. Five new species are described: Steinera isidiata Ertz & R.S. Poulsen, S. membranacea Ertz & R.S. Poulsen, S. lebouvieri Ertz, S. pannarioides Ertz & R.S. Poulsen and Henssenia subglaucella Ertz & R.S. Poulsen along with seven new combinations: Steinera intricata (Øvstedal) Ertz, S. latispora (Øvstedal) Ertz, S. olechiana (Alstrup & Søchting) Ertz & Søchting, S. subantarctica (Øvstedal) Ertz, Henssenia glaucella (Tuck.) Ertz, R.S. Poulsen & Søchting, H. radiata (P. James & Henssen) Ertz and H. werthii (Zahlbr.) Ertz, R.S. Poulsen & Søchting. An epitype is chosen for Henssenia glaucella and a neotype for H. werthii. “Steinera” symptychia has an isolated phylogenetic position in the Koerberiaceae and might represent a distinct, new genus. World-wide identification keys to the species of Henssenia and Steinera are provided.

Abstract: A new centric diatom genus, Ferocia Van de Vijver & Houk gen. nov. is described based on Melosira setosa Greville. Several samples collected in lava tunnels on Ile Amsterdam, a small isolated, volcanic island in the southern Indian Ocean where the latter taxon dominated the diatom flora, were investigated. The new genus is characterized by having heavily silicified, spherical frustules, connected into long chains by large, complex linking spines. Valves are dome-shaped with a high mantle with rounded to irregularly shaped areolae. Numerous small rimoportulae forming a marginal ring are present near the mantle edge. The cingulum is composed of a large number of narrow, open copulae. A second species, Ferocia ninae Van de Vijver & Houk sp. nov., is described from the nearby Crozet archipelago. Besides the typical features of the genus Ferocia, the rimoportulae in F. ninae are almost equidistant, the valves have a relatively low valve height and the spines are relatively small.         Both F. ninae and F. setosa were found in shaded lava tunnels with a sparse moss vegetation. The two species are illustrated and discussed based on detailed LM and SEM observations.