Polar Research

A thermophilic hormone-sensitive lipase family esterase Est1404 identified from an Antarctic bacterium Pseudomonas sp. E2-15

Yuanfang He — 2026-04-27

Esterases are a group of enzymes with a diverse range of uses in industry. We identified a novel hormone-sensitive lipase (HSL) in the esterase family, Est1404, through cloning and expression from the Antarctic bacterium Pseudomonas sp. E2–15, from soil collected on King George Island. Investigations showed that the Est1404 enzyme is a thermophilic esterase that maintains 90–100% activity throughout the temperature range of 60–90 °C. It exhibits the highest catalytic activity towards p-nitrophenol butyrate at 70 °C and pH 8.5. Est1404 was inhibited by the serine-modifying reagent phenylmethylsulfonyl fluoride, but thiol reagents such as dithiolthreitol stimulated its activity. Metal chelating chemicals, such as ethylenediaminetetraacetic acid, did not affect its activity. Phylogenetic analysis indicated that Est1404 is in the GDSAG subfamily of HSL. The enzyme contains a GDSAG motif with an active serine (S) positioned within a catalytic triad consisting of highly conserved Ser¹⁵⁶, Asp²⁵⁰ and His²⁸⁰ residues. The thermal stability of the Est1404 esterase makes it potentially useful in industrial catalysis.

Weathering above the tides: how iceberg-roll-generated waves shape Arctic rocky shores

Oskar Kostrzewa — 2026-04-13

A significant limitation of the current understanding of cold coast evolution is the paucity of field observations on the development of rocky coasts in glaciated parts of the Arctic. To address this gap, we present a pilot study that utilizes a Schmidt hammer to investigate variations in rock surface resistance across four distinct horizontal zones along the rocky bay of Zion Church, Ilulissat, near one of the prevailing routes of iceberg transport in western Greenland. The primary finding of the study is a substantial decrease in rock resistance within the area above the high-tide level. We relate this result mainly to waves generated by iceberg-roll events in conjunction with chemical and biological weathering. This case study seeks to elevate the status of iceberg-roll-generated waves from a mere curiosity to a substantial geomorphic agent that shapes the microrelief of Arctic coastlines.

Documenting an isolated and high-priority Arctic cultural heritage site: case study from Kapp Pettersen, Svenskøya, Svalbard

Iwo Wieczorek — 2026-03-10

With a warming climate, changing weather patterns and increased erosion from various permafrost- and marine-related processes, the cultural heritage (CH) sites in Svalbard are increasingly vulnerable to destruction. Documentation of CH sites in the Arctic can be very difficult on account of the harsh environment, remoteness (and associated costs), limited access time windows and—in Svalbard—the need to obtain permits from local authorities. The main objectives of this study are: (1) to document an isolated and prioritized CH site in Svalbard—the hut at Kapp Pettersen, Svenskøya—using an uncrewed aerial vehicle and ground photography; (2) to identify the effects of coastal erosion and permafrost-related processes on the cabin; and (3) to gain a better understanding of the landscape surrounding the site. We found that the shoreline had retreated, on average, by 0.42 m/yr between 2010 and 2024. This is significantly more than has been documented at other CH sites in Svalbard. The limited number of photographs of the hut meant that a three-dimensional representation could not be made. However, a detailed auditory description of the hut was made during the visit. This study highlights the challenges and limitations of Arctic CH documentation.

Comparative metagenomics of two shallow marine microbial communities in western Greenland

Daniel G. Dick — 2026-04-13

Metagenomic profiles of marine microbial communities from Greenlandic coastal waters remain scarce, despite the central role played by this region in discussions of global climate change. This study characterizes the taxonomic and functional structure of two near-shore shallow marine fjord mouth microbial communities from sites in western Greenland that differ in sea-surface temperatures, mean annual ice-coverage levels and annual glacial meltwater flux rates. Results indicate limited taxonomic and functional overlap between these two locations, with significant differences in the normalized abundance of 3372 species (25% of observed taxa) and 620 functional genes (49% of functional genes observed). At Sisimiut, a typical open-water “Baffin Bay” site characterized by moderate sea-surface temperatures, minimal annual sea-ice cover and limited glacial input, the metagenome is dominated by diverse chemolithotrophic taxa, including sulphate-reducing, nitrogen-fixing and methanogenic lineages. At the Ilulissat Icefjord, where low sea-surface temperatures, high turbidity, low salinity and strong glacial influences prevail, the community is less diverse and is dominated by psychrophilic (cold-adapted) bacteria such as Colwellia hornerae PAMC 20917. Functional profiles further distinguish these sites: the Ilulissat metagenome is enriched in genes common to ice-associated and cold-adapted metabolisms (e.g., exopolysaccharide biosynthesis, dimethyl-sulphide and dimethylsulfoniopropionate cycling), whereas these genes are comparatively rare at Sisimiut. Together, these data sets provide a descriptive baseline for these two sites and a framework for future comparative studies in the region.

Bowhead whales (Balaena mysticetus) are copycats, imitating sounds heard in their environment

Samuel M. Llobet — 2026-04-10

In this study, we provide evidence that bowhead whales (Balaena mysticetus) imitate bearded seal (Erignathus barbatus) calls, integrating them into their own elaborate songs, demonstrating this cetacean species’ capacity for complex vocal learning. Bowhead whales also appear to imitate additional species—narwhal (Monodon monoceros)—and even environmental noise (ice sounds) in the Svalbard area. This behaviour likely reflects evolutionary pressure related to song diversity, mating success and ecological adaptation.

An Adélie penguin (Pygoscelis adeliae) 200 km from the sea

Sebastien Descamps — 2026-04-07

This brief note reports an observation of an Adélie penguin (Pygoscelis adeliae) 200 km from the open sea, at Troll Research Station, in Dronning Maud Land, Antarctica, on the morning of 5 January 2026. The bird, which appeared to be in good condition, was not interfered with and was last seen walking away from the station in the afternoon. This observation and previous reports of penguin signs so far inland are rare and raise questions about how these birds navigate.

Actor participation in the Arctic Council, 1998–2025: a new data set

Anna Ivanova — 2026-04-16

The Arctic Council, once the primary forum for Arctic governance, has been facing significant disruptions since 2022, raising questions about the future direction of regional cooperation. Stored at the Arctic Data Center in the US, the ArcticPart data set covers over 25 years of participation in 171 meetings of the Arctic Council, including Ministerial, Senior Arctic Officials and selected working, expert and task force groups. It offers the most complete and systematically organized record of actor participation from 1998 to 2025. This data set provides opportunities to analyse the evolution of Arctic governance, including changes in member state participation after 2022, the shift of meetings to the working group level, the changing role of observers and non-state actors in maintaining cooperation and the effects of chairship rotation.