Abstract: During the last decade, increasing information on little auk (Alle alle) biology, ecology and behaviour has been reported. However, only a few of these studies have focused on the breeding population in the Avanersuaq (Thule) district of Northwest Greenland, where 80 % of the global little auk population is estimated to breed. This study reports on the chick diet composition from one of the largest colonies, the Paakitsoq colony, located on the south-eastern margin of the North Water (NOW) Polynya. Results revealed the highest proportion of Calanus hyperboreus, a large lipid-rich copepod, in chick diet reported for any little auk colony. Results confirmed that the cold,
highly productive waters of the NOW Polynya are favourable foraging grounds for the little auks during the breeding season. Species diversity within and between the chick meals was low, which probably reflects a high availability of a few preferred prey species. Individual chick meals were generally low in number of prey items and total energy content compared with other published results. This may be explained by a higher feeding frequency or by the samples being collected late in the breeding period (during late chick rearing), when chicks have a reduced growth rate and may require less energy than at earlier developmental stages.

Abstract: During July 7-12, 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapour isotopic composition using surface in situ observations in Bermuda Island, South Greenland coast (Ivittuut) and Northwest Greenland ice sheet (NEEM), as well as remote sensing observations (IASI instrument on-board MetOp-A), depicting propagation of similar surface and mid-tropospheric humidity and δD signals. Simulations using Lagrangian moisture source diagnostic and water tagging in a regional model showed that Greenland was affected by an atmospheric river transporting moisture from the western subtropical North Atlantic Ocean, which is coherent with observations of snow pit impurities deposited at NEEM. At Ivittuut, surface air temperature, humidity and δD increases are observed. At NEEM, similar temperature increase is associated with a large and long-lasting ~100 δD enrichment and ~15 deuterium excess decrease, thereby reaching Ivittuut level. We assess the simulation of this event in two isotope-enabled atmospheric general circulation models (LMDz-iso and ECHAM5-wiso). LMDz-iso correctly captures the timing of propagation for this event identified in IASI data but depict too gradual variations when compared to surface data. Both models reproduce the surface meteorological and isotopic values during the event but underestimate the background deuterium excess at NEEM. Cloud liquid water content parametrization in LMDz-iso poorly impacts the vapour isotopic composition. Our data demonstrate that during this atmospheric river event the deuterium excess signal is conserved from the moisture source to Northwest Greenland.

Abstract: Aim. Dispersal explains the disjunct distributions of many austral plant lineages.
However, the role of Antarctica is largely uncertain and the routes of
dispersal have remained speculative. Based on niche conservatism we can make
predictions about the timing of disjunction establishment, as well as the availability
of direct transoceanic, Antarctic stepping-stone, and out-of-Antarctica
dispersal routes over time. We evaluate these predictions using molecular
divergence time estimates for the establishment of disjunct distributions across
multiple plant lineages.
Location. Southern Hemisphere.
Methods. We estimated the timing of disjunction establishment and determined
habitat affinities for 72 austral plant groups. We used Wilcoxon rank
sum tests to compare the timing of disjunction establishment between cold
and temperate climate lineages for the full data set, as well as within several
subsets. We compared our results with those from a literature survey.
Results. As niche conservatism predicts, the timing of disjunction establishment
in cold and temperate climate austral lineages is consistent with the availability
of the corresponding habitats over time. Our results also suggest that
disjunction establishment has involved a combination of Antarctic and direct
dispersal routes. For cold climate lineages, both out-of-Antarctica and direct
dispersal routes are required to explain the observed estimates, while stepping
stone routes cannot be ruled out. It appears that for these lineages the importance
of the three dispersal routes differs with environmental, geographical and
temporal context.
Main conclusions. Both direct and Antarctic dispersal routes are necessary to
explain the establishment of contemporary austral distributions. Evidence that
some taxa were, until recently, restricted to Antarctica changes how we view
the evolutionary histories of austral floras and the lineages they contain. Moreover,
that we detect differences in the importance of alternative dispersal routes
suggests that long-distance plant dispersal processes can be explicitly incorporated
into models of climate change response.

Abstract: Assessing the enormous diversity of Southern Ocean benthic species and their evolutionary histories is a central task in the era of global climate change. Based on mitochondrial markers, it was recently suggested that the circumpolar giant sea spider Colossendeis megalonyx comprises a complex of at least six cryptic species with mostly small and non-overlapping distribution ranges. Here, we expand the sampling to include over 500 mitochondrial COI sequences of specimens from around the Antarctic. Using multiple species delimitation approaches, the number of distinct mitochondrial OTUs increased from six to 15-20 with our larger dataset. In contrast to earlier studies, many of these clades show almost circumpolar distributions. Additionally, analysis of the nuclear internal transcribed spacer region for a subset of these specimens showed incongruence between nuclear and mitochondrial results. These mito-nuclear discordances suggest that several of the divergent mitochondrial lineages can hybridize and should not be interpreted as cryptic species. Our results suggest survival of C. megalonyx during Pleistocene glaciations in multiple refugia, some of them probably located on the Antarctic shelf, and emphasize the importance of multi-gene datasets to detect the presence of cryptic species, rather than their inference based on mitochondrial data alone.