Global diversity and geography of planktonic marine fungi

Abstract

Growing interest in understanding the relevance of marine fungi to food webs, biogeochemical cycling, and biological patterns necessitates establishing a context for interpreting future findings. To help establish this context, we summarize the diversity of cultured and observed marine planktonic fungi from across the world. While exploring this diversity, we discovered that only half of the known marine fungal species have a publicly available DNA locus, which we hypothesize will likely hinder accurate highthroughput sequencing classification in the future, as it does currently. Still, we reprocessed >600 high-throughput datasets and analyzed 4.9 × 10 9 sequences (4.8 × 10 9 shotgun metagenomic reads and 1.0 × 10 8 amplicon sequences) and found that every fungal phylum is represented in the global marine planktonic mycobiome; however, this mycobiome is generally predominated by three phyla: the Ascomycota, Basidiomycota, and Chytridiomycota. We hypothesize that these three clades are the most abundant due to a combination of evolutionary histories, as well as physical processes that aid in their dispersal. We found that environments with atypical salinity regimes (>5 standard deviations from the global mean: Red Sea, Baltic Sea, sea ice) hosted higher proportions of the Chytridiomycota, relative to open oceans that are dominated by Dikarya. The Baltic Sea and Mediterranean Sea had the highest fungal richness of all areas explored. An analysis of similarity identified significant differences between oceanographic regions. There were no latitudinal gradients of marine fungal richness and diversity observed. As more high-throughput sequencing data become available, expanding the collection of reference loci and genomes will be essential to understanding the ecology of marine fungi.

Global diversity and biogeography of theZostera marinamycobiome

“…This is generally consistent with the proportion of fungi in other marine eukaryotic studies (e.g. 1.3% fungal sequences in Hassett et al (2020)).…”

“…In comparison to the greater than 120,000 terrestrial fungal species known (Hawksworth & Lücking, 2017), there are currently only ∼1,692 described species of marine fungi, though estimates of the true diversity of these organisms is much higher (Jones, 2011;Jones et al, 2015Jones et al, , 2019. Recent studies have examined the global distribution of marine planktonic, pelagic, and benthic fungi (Tisthammer et al, 2016;Morales et al, 2019;Hassett et al, 2020), yet the distribution of host-associated fungi in the marine environment is still relatively unknown. Fungi have been reported in association with many marine animals including sponges (Gao et al, 2008), corals (Littman et al, 2011) and other invertebrates (Yarden, 2014), with algae and seaweeds (Zuccaro et al, 2008;Gnavi et al, 2017), and flowering plants, like seagrasses (Borovec & Vohník, 2018).…”

Diverse groups of fungi are associated with plastics in the surface waters of the Western South Atlantic and the Antarctic Peninsula

“…We suggest that the same does not happen with plastic‐associated fungi from WSA and AP. Many of the fungal taxa found on the plastics were found in both broad regions, e.g., the genera Aspergillus and Cladosporium and the order Pleosporales, and indeed these genera are cosmopolitan within the marine environment and found in many locations (Hassett, Vonnahme, Peng, Jones, & Heuzé, 2019; Richards et al., 2012; Rosa, 2019). Some of the fungi OTUs identified in the specific and general data sets were common to both WSA and AP, e.g., Sterigmatomyces halophilus, Aspergillus versicolor and Cladosporium sp.…”

“…Detection of spores raises an important question about the activity of several of the fungal taxa associated with our plastics. However, given that the majority of the groups have been reported in marine environments world‐wide (Hassett, Vonnahme, et al, 2019; Richards et al., 2015; Taylor & Cunliffe, 2016) and several studies have used RNA based approaches (as a marker of active taxa RNA is degraded more rapidly than DNA and is continually produced by activity metabolising cells) and detected similar taxa in our study it is likely that majority of taxa are indeed active (Orsi, Biddle, & Edgcomb, 2013; Richards et al., 2015). In marine plastic pollution research, further work should aim to address the issue of activity with RNA based techniques and microscopy.…”

Fungal Communities in Sediments Along a Depth Gradient in the Eastern Tropical Pacific

“…Furthermore, what is known about the microbial ecology in deep-sea sediments is mainly about bacteria and archaea ( Edgcomb et al, 2011 ; Nagano and Nagahama, 2012 ; Dekas et al, 2016 ; Xu et al, 2018 ). Therefore, detailed knowledge of deep-sea fungi is required to understand better the overall fungal contribution to marine food webs and biogeochemical cycles at the global scale ( Manohar and Raghukumar, 2013 ; Barone et al, 2018 ; Drake and Ivarsson, 2018 ; Grossart et al, 2019 ; Román et al, 2019 ; Hassett et al, 2020 ).…”