Research above the Arctic Circle reveals an unusually high diversity of soil fauna
Ing. Marek Renčo, PhD., from the Parasitological Institute of the Slovak Academy of Sciences (SAS) in Košice, was part of an international research team studying soil fauna in the Arctic tundra in central Spitsbergen, Svalbard. In Petuniabukta Bay, he investigated how selected Arctic plant species influence soil nematode communities (roundworms).
Due to the harsh climatic conditions, some plant species develop specific growth forms known as cushion-forming plants—namely Silene acaulis, Saxifraga oppositifolia, and Dryas octopetala. Others, such as Salix polaris, Cassiope tetragona, and Carex rupestris, form low-growing vegetation referred to as mat-forming plants.
“The plant species and its growth form proved to be key factors determining the composition, abundance, and species diversity of soil nematode communities. Under the extreme conditions of the Arctic tundra, Silene acaulis (stalkless campion) creates the most favourable microenvironment in the form of compact cushions. These supported nematode communities with the highest abundance, greatest species diversity, highest biomass, and the most stable and well-developed food web structure,” explains Marek Renčo from the Parasitological Institute of the SAS. Favourable conditions for soil nematodes were also observed in the rhizosphere of Dryas octopetala (mountain avens) and Carex rupestris (rock sedge). In total, the researchers identified 109 species of soil nematodes belonging to 66 genera—an indication of remarkable diversity despite the severe climatic conditions. Bacteria-feeding species dominated (45 species), followed by plant parasites (20 species), fungal feeders (19 species), omnivores (18 species), and predators (7 species).
“This research shows that even in a landscape seemingly limited by cold and nutrient scarcity, plants play a fundamental role in shaping soil life. Tundra vegetation is not merely a passive product of harsh conditions; it actively structures the entire ecosystem, including what lies hidden beneath the soil surface,” the researcher adds.
Equally intriguing findings emerged from research conducted in so-called cryoconites on the Lenangsbreen Glacier in Norway. Cryoconites are small meltwater pools that form on glacier surfaces during summer, freeze in winter, and reappear the following summer. Given the constant temperature of around 0 °C, high UV radiation, and minimal organic material, nematodes were not expected to occur there.“The discovery of a nematode population was therefore particularly surprising. These specimens were later
classified as Monhysteridae. Unfortunately, due to insufficient DNA material for analysis and limited quality of specimens for morphological identification, further species-level classification was not possible. Nevertheless, this represents the first confirmed global record of Nematoda in glacial cryoconites,” states Renčo.
Both studies were carried out in collaboration with the Institute of Soil Biology and Biogeochemistry of the Biology Centre of the Czech Academy of Sciences in České Budějovice. They were financially supported by the Czech Science Foundation (project No. 22-28778S).
Prepared and photo: Marek Renčo, Institute of Parasitology SAS