- 1Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Department of Biology and Environmental Science, Linnaeus University, Kalmar, Sweden (janina.rahlff@lnu.se)
- 2Aero-Aquatic Virus Research Group, Faculty of Mathematics and Computer Science, Friedrich Schiller University Jena, Jena, Germany
- 3Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), Jena, Germany
- 4York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
In polar regions, aquatic viruses play a pivotal role in shaping microbial communities yet face significant challenges such as low host availability and harsh environmental conditions. During the Synoptic Arctic Survey 2021 aboard the icebreaker Oden (Snoeijs-Leijonmalm, 2022), we investigated viral diversity, survival mechanisms, and host interactions in the Central Arctic's surface microlayer (SML), the uppermost millimeter of the ocean, and compared them with ~60 cm depth from the ocean and a melt pond. This study addresses the knowledge gap surrounding near-atmosphere aquatic ecosystems, highlighting the SML as a critical platform for viral adaptation and dispersal in one of Earth's most extreme environments. Our study uncovered 1154 viral operational taxonomic units (vOTUs) >10 kb in size, two-thirds of which were predicted bacteriophages (viruses that infect bacteria). Flavobacteriales were identified as key hosts, with one dominant melt pond vOTU linked to a Flavobacterium sp. isolate. Melt pond viral communities displayed lower diversity compared to open water, indicating selective pressures in these transient systems. We found that 17.2% of vOTUs carried 87 unique auxiliary metabolic genes (AMGs) involved in pathways such as amino acid, glycan polymer, and porphyrin metabolism, supporting host survival under extreme conditions. Notably, 16 vOTUs encoded glycerol-3-phosphate cytidylyltransferase (tagD), which may function in cryoprotection. While lytic phages could not be found via plaque assays, prophage induction experiments using the bacterial isolate Leeuwenhoekiella aequorea Arc30 and mitomycin C revealed active phages with siphovirus morphology and minimal protein similarity to known phages. Our findings also highlight the SML’s role in viral dispersal, as vOTU abundance correlated with spread across the Arctic via the boundary layer. These sophisticated viral strategies emphasize their ability to thrive in remote, inhospitable, and host-limited environments (Rahlff et al., 2024). These discoveries underscore the importance of viruses in Arctic ecosystem dynamics, influencing microbial communities, and in the broader context, nutrient cycling, gas exchange and resilience to climate change.
References:
Rahlff, J., Westmeijer, G., Weissenbach, J., Antson, A., & Holmfeldt, K. (2024). Surface microlayer-mediated virome dissemination in the Central Arctic. Microbiome, 12(1), 218. https://doi.org/10.1186/s40168-024-01902-0
Snoeijs-Leijonmalm, P. (2022). Expedition Report SWEDARCTIC Synoptic Arctic Survey 2021 with icebreaker Oden. In: Swedish Polar Research Secretariat.
How to cite: Rahlff, J., Westmeijer, G., Weissenbach, J., Antson, A., and Holmfeldt, K.: Surface microlayer ecosystems as platforms for viral adaptation and dispersal in the Central Arctic, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1665, https://doi.org/10.5194/egusphere-egu25-1665, 2025.
