Fungi is ubiquitous in marine environment and its role in organic matter cycling is emerging alongside heterotrophic prokaryotes. Here, we examined the fungi community recovered from four discrete size-fractions, from 0.8 to 2000 μm, from global sunlit oceans by analyzing 18s rDNA amplicon sequencing data. We found a decrease in fugal diversity from the smallest to the largest size-fractions with drastic changes in the community composition. Additionally, the fungi relative abundance also decreased toward large fractions but become more correlated with the chlorophyll concentration. Notably, 12% of fungal species was identified as feature species and accounted for over 75% of the total fungal abundance. These feature species were indicative for community response to environmental changes between size fractions, depth layers and oceanic regions, but barely interacted with other fungal species as reflected by co-occurrence networks. Our results provided comprehensive results for the biodiversity and biogeography of fungi community living in the sunlit ocean.
 

marine fungi, biogeography, size-fraction