Arctic aquatic ecosystems are important at both regional and global scales, however at present we have a limited understanding of the fungi that thrive in these habitats.  Sea ice ecosystems were sampled along a transect from second year ice (SYI) on Greenland’s shelf to first year ice (FYI) at the North Pole and off Svalbard. Two major Arctic River systems, the Lena and Kolyma, were also sampled in a separate campaign. Environmental DNA and RNA were used to assess fungal abundance and diversity. Greenland shelf SYI contains distinct fungal communities compared to younger FYI in other regions. Surface SYI was dominated by yeasts. Chytrids dominated the fungal communities in the bottom ice and showed potential diatom host specificity. Chytrids also dominated the Kolyma fungal communities. In the Lena, fungi were more diverse, with chytrids, as well as Ascomycota and unidentified fungi showing similar abundances. Chytrid in both river systems were dominated by the algal parasite Zygophlyctis. The dominating Zygophlyctis were compared with diatom and cyanobacterial hosts to determine possible parasite-host relationships. Zygophlyctis correlated significantly with the diatoms Aulacoseira and Synedra, both genera have been shown to be hosts for Zygophlyctis in temperate aquatic ecosystems. Potential Zygophlyctis dynamics showed seasonal-scale shifts in the Kolyma River. This work is set in the context of the rapidly changing Arctic and developing a better understanding of the Arctic ecosystems that are being lost or drastically modified because of global climate change.  

Primary Presenter: Michael Cunliffe, Marine Biological Association (micnli@mba.ac.uk)

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