Community composition of aquatic fungi across the thawing Arctic

Thermokarst activity at permafrost sites releases considerable amounts of ancient carbon to the atmosphere. A large part of this carbon is released via thermokarst ponds, and fungi could be an important organismal group enabling its recycling. However, our knowledge about aquatic fungi in thermokarstic systems is extremely limited. In this study, we collected samples from five permafrost sites distributed across circumpolar Arctic and representing different stages of permafrost integrity. Surface water samples were taken from the ponds and, additionally, for most of the ponds also the detritus and sediment samples were taken. All the samples were extracted for total DNA, which was then amplified for the fungal ITS2 region of the ribosomal genes. These amplicons were sequenced using PacBio technology. Water samples were also collected to analyze the chemical conditions in the ponds, including nutrient status and the quality and quantity of dissolved organic carbon. This dataset gives a unique overview of the impact of the thawing permafrost on fungal communities and their potential role on carbon recycling.

Wicklowia phuketensis (Wicklowiaceae, Pleosporales), a novel freshwater taxon from Thailand

An investigation of aquatic fungi in Thailand resulted in the collection and isolation of a new species of Wicklowia (Wicklowiaceae) from submerged wood. Wicklowia phuketensis sp. nov. differs from known species in morphology and multigene phylogenetic analyses. Both W. submersa and W. phuketensis lack appendages at both ends, while W. aquatica has basal appendages. Wicklowia phuketensis differs from other species in the dimensions of the ascomata, asci and ascospores. The combined LSU and SSU sequence data placed the new species within Wicklowiaceae.