Multi-omics for studying and understanding polar life

Abstract

Polar ecosystems are experiencing amongst the most rapid rates of regional warming on Earth. Here, we discuss 'omics' approaches to investigate polar biodiversity, including the current state of the art, future perspectives and recommendations. We propose a community road map to generate and more fully exploit multi-omics data from polar organisms. These data are needed for the comprehensive evaluation of polar biodiversity and to reveal how life evolved and adapted to permanently cold environments with extreme seasonality. We argue that concerted action is required to mitigate the impact of warming on polar ecosystems via conservation efforts, to sustainably manage these unique habitats and their ecosystem services, and for the sustainable bioprospecting of novel genes and compounds for societal gain.

Fig. 1. Different polar environments.

A Scientific divers inspect benthic communities on a submerged wall on Anchorage Island, near Rothera Research Station on the Antarctic Peninsula. Photo from BAS photo library. Photographer John Withers. B The Arctic winter on the MOSAiC expedition, during which the German research icebreaker Polarstern spent a year drifting through the Arctic Ocean trapped in the ice (https://mosaic-expedition.org/). Photographer Marcel Nicolaus, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany. C McMurdo Dry Valleys in Victoria Land, East Antarctica. These valleys are an unusual region of extremely low humidity without snow or ice cover, which have not seen precipitation for ~2 million years. Photo from BAS photo library. Photographer John Shears. D Arctic intertidal region near Upernavik, Greenland. Intertidal species include blue mussels (Mytilus edulis) and macroalgae. Photographer Jakob Thyrring. E Sea ice upturned by the ice strengthened research vessel RRS Bransfield in the Weddell Sea, Antarctica exposing ice algae growing on and within the underside of the sea ice. Ice algae are an abundant source of food for overwintering krill. Photo from BAS photo library. Photographer Chris Gilbert. F Arctic permafrost in Svalbard dominated by biological soil crusts with characteristic geomorphic feature of tundra polygons. Photographer Svenja Heesch, University of Rostock. G Nunatak on the northern Churchill Peninsula (Oscar II Coast, Graham Land) and frozen freshwater melt pool. Photo from BAS photo library. Photographer Teal Riley. H Arctic tundra on Svalbard with endemic reindeer. Photographer Melody Clark (BAS). All photographs published with permission and all supporting imagery from the BAS Image Collection is published according to the image rights agreement between each photographer and the British Antarctic Survey.

Fig. 2. Examples of polar species with unique adaptations.

More extensive details of adaptations with associated references in Supplementary Note 2. A Polar bears have a modified cardiovascular system allowing them to tolerate chronically elevated levels of serum cholesterol in their diet. Photo from BAS photo library. Photographer Angelika Renner. B Antarctic sea spiders are examples of polar gigantism. Photo from BAS photo library. Photographer Dave Bowden. C Antarctic diatoms produce ice antifreeze proteins to survive in sea ice. Photograph from Thomas Mock, University of East Anglia. D Copepods accumulate lipids (up to 70% of individual dry weight) to survive Arctic winters. Photograph from Kim Last, Scottish Association for Marine Sciences. E Antarctic springtails survive down to −30 °C via rapid cold hardening. Photo from BAS photo library. Photographer Pete Bucktrout. F Icefish are the only vertebrates that lack haemoglobin. Photograph from Gianfranco Santovito, University of Padua. G Antarctic endolithic communities in rock survive the most extreme conditions. Photo from BAS photo library. Photographer David Wynn-Williams. H Krill has the largest biomass of any wild animal on the planet. Photo from BAS photo library. Photographer Pete Bucktrout. I Arctic tern undertakes the longest migration on Earth. Photo from BAS photo library. Photographer Callan Duck. J Antarctic nematodes normally live in temperatures of down to −7 °C, but some can survive at −80 °C. Photograph from Kevin Newsham, British Antarctic Survey. K Arctic Bell-heather thrives in deep snow over winter. Photographer from Melody Clark, British Antarctic Survey. L Polar cod shows convergent evolution of antifreeze glycoprotein to survive the cold. Photograph from Till Luckenbach, Helmholtz Centre for Environmental Research—UFZ. M Blue mussels and macroalgae can survive to 36 °C in the Greenland intertidal. Photographer Jakob Thyrring, Aarhus University. N Ectomycorrhiza colonise plant roots and play vital roles in protecting the plant from extreme conditions. Photographer Kevin Newsham, British Antarctic Survey. O An Ocean quahog holds the record of the longest-lived animal on Earth. Photographer Al Wanamaker, Iowa State University. P Antarctic fur seal genomics is revealing signals of past hunting pressures. Photographer Joseph Hoffman, University of Bielefeld. All photographs published with permission and all supporting imagery from the BAS Image Collection is published according to the image rights agreement between each photographer and the British Antarctic Survey.

Fig. 3. Schematic showing simplified polar ecosystems.

Omics can be used to evaluate biodiversity across the whole of the polar Tree of Life from microbes in the ocean, land, ice and permafrost through to the large charismatic mega fauna, such as polar bears, whales, seals and sea birds, as discussed in the main text. Such analyses will reveal adaptations to life in the cold from the single gene to whole animal levels. Furthermore, sequencing multiple individuals in different populations, as represented by the groups of seals, penguins and polar bears will reveal evolutionary histories and population variability, which may provide indications of future resilience. Sequencing of gut contents from any of the species depicted can provide insight into current and changing food webs on land and in the sea. Using the past to predict the future is represented by the frozen woolly mammoth and permafrost. Long-term monitoring for surveillance is represented at both poles by the two research stations, with automatic sampling depicted by the unmanned vehicle autosub. Related to surveillance is the pictogram of the ship, representing the potential introduction of alien invasives, as can be monitored using eDNA.