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ORIGINAL RESEARCH article

Front. Microbiol.

Sec. Terrestrial Microbiology

This article is part of the Research TopicMicrobial Diversity and Survival Strategies in Polar EnvironmentsView all 3 articles

Summer and autumn photosynthetic activity in High Arctic biological soil crusts and their winter recovery

Provisionally accepted
  • 1Botanicky ustav Akademie ved Ceske republiky Vedecke pracoviste Trebon, Třeboň, Czechia
  • 2Univerzita Karlova Prirodovedecka fakulta, Prague, Czechia
  • 3Universitat zu Koln Institut fur Pflanzenwissenschaften, Cologne, Germany
  • 4Jihoceska Univerzita v Ceskych Budejovicich Prirodovedecka Fakulta, Ceske Budejovice, Czechia
  • 5Zapadoceska univerzita v Plzni Fakulta pedagogicka, Pilsen, Czechia

The final, formatted version of the article will be published soon.

Introduction: Biological soil crusts, found in arid and semi-arid areas worldwide, play a crucial role in the carbon cycle. This study analysed biocrusts from three different altitudes in Svalbard (High Arctic) in 2022–2024. Methods and Results: Monitoring of microclimatic parameters, including irradiance, humidity, air, and soil temperature revealed unexpected extremes at the lowest elevation site. Molecular methods were used to determine the diversity of microalgae, revealing the presence of Trebouxiophyceae and Chlorophyceae as the dominant eukaryotic algal groups. Among the cyanobacteria, the dominant taxonomical groups were Nostocales, Pseudanabaenales, and Oscillatoriales. Measured photosynthetic activity was largely driven by irradiance across the different seasons and locations. Higher maximum quantum yield (FV/FM) values (approximately 0.6) were measured at lower irradiance levels (<100 µmol m−2 s−1). Photosynthetic activity was observed in early October 2022, and diurnal changes were even noticeable at subzero temperatures in late October 2023, with the low irradiance curve being mirrored by the development of FV/FM. Furthermore, thawed biocrusts in winter exhibited the ability to rapidly restore photosynthetic activity, which was also supported by the expression of photosynthesis-related genes. Metatranscriptomic analysis revealed that the differential gene expression observed for the D1, RbcS, Ohp1, and ELIP proteins suggests that light stress induced photoinhibition plays a major role in biocrusts, particularly in winter. Conclusion: The biocrusts can remain active for extended periods and provide carbon fixation during times when tundra plants primarily engage in respiration, making them very important for the polar environment.

Keywords: Arctic, biological soil crust, Cyanobacteria, diurnal cycle, Microalgae, Photosynthetic activity

Received: 12 Aug 2025; Accepted: 31 Oct 2025.

Copyright: © 2025 Hejduková, Pushkareva, Kvíderová, Becker and Elster. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Eva Hejduková, hejdukova.eve@gmail.com

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