Applicability of cryoconite consortia of microorganisms and glacier-dwelling animals in astrobiological studies

For several years it has been of interest to astrobiologists to focus on Earth’s glaciers as a habitat that can be similar to glaciers on other moons and planets. Microorganisms on glaciers form consortia – cryoconite granules (cryoconites). They are granular/spherical mineral particles connected with archaea, cyanobacteria, heterotrophic bacteria, algae, fungi, and micro animals (mainly Tardigrada and Rotifera). Cryophilic organisms inhabiting glaciers have been studied in different aspects: from taxonomy, ecology and biogeography, to searching of biotechnological potentials and physiological strategies to survive in extreme glacial habitats. However, they have never been used in astrobiological experiments. The main aim of this paper is brief review of literature and supporting assumptions that cryoconite granules and microinvertebrates on glaciers, are promising models in astrobiology for looking for analogies and survival strategies in terms of icy planets and moons. So far, astrobiological research have been conducted on single strains of prokaryotes or microinvertebrates but never on a consortium of them. Due to the hypothetical similarity of glaciers on the Earth to those on other planets these cryoconites consortia of microorganisms and glacier microinvertebrates may be applied in astrobiological experiments instead of the limno-terrestrial ones used currently. Those consortia and animals have qualities to use them in such studies and they may be the key to understanding how organisms are able to survive, reproduce and remain active at low temperatures

Area, depth and elevation of cryoconite holes in the Arctic do not influence Tardigrada densities

Water bears (Tardigrada) are known as one of the most extremophile animals in the world. They inhabit environments from the deepest parts of the oceans up to the highest mountains. One of the most extreme and still poorly studied habitats which tardigrades inhabit are cryoconite holes. We analysed the relation between area, depth, elevation and tardigrades densities in cryoconite holes on four glaciers on Spitsbergen. The mean (+/- SD) of cryoconite area was 1287.21 +/- 2400.8 cm(2), while the depth was on average 10.8 +/- 11.2 cm, the elevation 172.6 +/- 109.66 m a.s.l., and tardigrade density 24.9 +/- 33.0 individuals per gram of wet material (n = 38). The densities of tardigrades on Hans Glacier reached values of up to 168 ind. cm(3), 104 ind. g(-1) wet weight, and 275 ind. g(-1) dry weight. The densities of tardigrades of the three glaciers in Billefjorden were up to 82 ind. cm2, 326 ind. g(-1) wet weight and 624 ind. g(-1) dry weight. Surprisingly, although the model included area, depth and elevation as independent variables, it cannot explain Tardigrada density in cryoconite holes. We propose that due to the rapid melting of the glacier surface in the Arctic, the constant flushing of cryoconite sediments, and inter-hole water-sediment mixing, the functioning of these ecosystems is disrupted. We conclude that cryoconite holes are dynamic ecosystems for microinvertebrates in the Arctic

Diversity and distribution of Tardigrada in Arctic cryoconite holes

Despite the fact that glaciers and ice sheets have been monitored for more than a century, knowledge on the glacial biota remains poor. Cryoconite holes are water-filled reservoirs on a glacier's surface and one of the most extreme ecosystems for micro-invertebrates. Tardigrada, also known as water bears, are a common inhabitant of cryoconite holes. In this paper we present novel data on the morphology, diversity, distribution and role in food web of tardigrades on Arctic glaciers. From 33 sampled cryoconite holes of 6 glaciers on Spitsbergen, in 25 tardigrades were found and identified. Five taxa of Tardigrada (Eutardigrada) were found in the samples, they are: Hypsibius dujardini, Hypsibius sp. A, Isohypsibius sp. A., Pilatobius recamieri, and one species of Ramazzottiidae. H. dujardini and P. recamieri were previously known from tundra in the Svalbard archipelago. Despite the number of studies on Arctic tundra ecosystems, Hypsibius sp. A, one species of Ramazzottiidae and Isohypsibius sp. A are known only from cryoconite holes. Tardigrade found in this study do not falsify the hypothesis that glaciers and ice sheets are a viable biome (characteristic for biome organisms assemblages -tardigrades). Diagnosis of Hypsibius sp. A, Isohypsibius sp. A, and species of Ramazzottiidae with discussion on the status of taxa, is provided. To check what analytes are associated with the presence of tardigrades in High Arctic glacier chemical analyses were carried out on samples taken from the Buchan Glacier. pH values and the chemical composition of anions and cations from cryoconite holes water from the Buchan Glacier are also presented. The current study on the Spitsbergen glaciers clearly indicates that tardigrade species richness in cryoconite holes is lower than tardigrade species richness in Arctic tundra ecosystems, but consists of unique cryoconite hole species. As cryoconite tardigrades may feed on bacteria as well as algae, they are primary consumers and grazers-secondary consumers of the decomposer food chain in this extreme ecosystem

The terrestrial and freshwater invertebrate biodiversity of the archipelagoes of the Barents Sea; Svalbard, Franz Josef Land and Novaya Zemlya

Arctic terrestrial ecosystems are generally considered to be species poor, fragile and often isolated. Nonetheless, their intricate complexity, especially that of the invertebrate component, is beginning to emerge. Attention has become focused on the Arctic both due to the importance of this rapidly changing region for the Earth and also the inherent interest of an extreme and unique environment. The three archipelagoes considered here, Svalbard, Franz Josef Land and Novaya Zemlya, delineate the Barents Sea to the west, north and east. This is a region of convergence for Palearctic and Nearctic faunas re-colonising the Arctic following the retreat of the ice after the Last Glacial Maximum (LGM). Despite the harsh Arctic environment and the short period since deglaciation, the archipelagoes of the Barents Sea are inhabited by diverse invertebrate communities. But there is an obvious imbalance in our knowledge of many taxa of each archipelago, and in our knowledge of many taxa. Research effort in Svalbard is increasing rapidly while there are still few reports, particularly in the western literature, from Franz Josef Land and Novaya Zemlya. Nevertheless, there appears to be a surprising degree of dissimilarity between the invertebrate faunas, possibly reflecting colonization history. We provide a baseline synthesis of the terrestrial and freshwater invertebrate fauna of the Barents Sea archipelagoes, highlight the taxa present, the characteristic elements of fauna and the complexity of their biogeography. In doing so, we provide a background from which to assess responses to environmental change for a region under increasing international attention from scientific, industrial and political communities as well as non-governmental organizations and the general public

Inventory of the terrestrial and freshwater fauna of the Svalbard archipelago

This is an inventory created by searching species names from almost 800 scientific publications from 1869 until 2023. This inventory was then assessed by taxon experts and synonyms or obvious errors removed. The inventory forms the data for the redescription of the Svalbard terrestrial and freshwater invertebrate fauna appearing in Coulson et al. in prep. Arctic Science