Marine Fungal Ecology and Biodiversity

Fungi are integral yet historically underappreciated constituents of marine ecosystems, colonising habitats from sunlit surface waters to the deep‐sea subsurface. They encompass a wide phylogenetic breadth, including Chytridiomycota, Ascomycota and Basidiomycota lineages, many of which remain undescribed. Marine fungi contribute to organic matter degradation, nutrient cycling and the formation and turnover of particulate aggregates, thereby influencing the marine carbon pump. Parasitic and symbiotic interactions with phytoplankton, algae and invertebrates can regulate host population dynamics and shape community succession. Extremotolerant fungi inhabiting hypersaline brines and glacial ice employ specialised osmoadaptation strategies and possess enzymes active at low temperatures and high salinities, suggesting biotechnological potential. Despite advances in environmental DNA and RNA sequencing, large gaps persist in mapping fungal distribution, elucidating life cycles and quantifying ecological functions across biomes. A concerted integration of molecular surveys, cultivation efforts and process‐level experiments is essential to fully appreciate the global significance of marine fungal diversity.

Research from Nature Portfolio

Analyses of millions of ribosomal RNA sequences from diverse marine and freshwater projects have revealed that chytrid‐like fungi dominate aquatic fungal assemblages, often representing over half of all reads. These novel chytrid lineages display high species richness and pronounced niche separation, with many sequences affiliating to phytoplankton‐parasitic clades, underscoring a key role in algal bloom dynamics and carbon transformation. In high‐latitude sediments, pyrosequencing of the internal transcribed spacer region uncovered over 100 fungal operational taxonomic units, spanning multiple phyla and including many unknown lineages. Spatial patterns among basins indicate that sedimentary fungal communities are influenced by terrestrial inputs, water mass circulation and local environmental gradients, offering a model for studying community assembly in polar marine sediments.

Marine Fungal Ecology and Biodiversity publication trend

The graph below shows the total number of articles in marine fungal ecology and biodiversity across all publications each year (not limited to Nature Index journals).

Technical terms

Mycoplankton: Free‐living fungal communities inhabiting the water column, distinct from benthic or particle‐associated fungi.

Chytrid: Member of Chytridiomycota, often zoosporic parasites of algae and other eukaryotes.

Operational taxonomic unit (OTU): A cluster of similar DNA sequences used as a proxy for species in environmental surveys.

Biological carbon pump: The process by which organic carbon is transported from the surface ocean to the deep sea, partly mediated by microbial communities.

Osmolyte: Small organic compound accumulated by cells to maintain osmotic balance under stress conditions such as high salinity or desiccation.

References

1. Understanding Fungi in Glacial and Hypersaline Environments. Annual Review of Microbiology (2023).
2. The largely neglected ecological role of oceanic pelagic fungi. Trends in Ecology & Evolution (2023).
3. Fungi in the Marine Environment: Open Questions and Unsolved Problems. mBio (2019).
4. Integrating chytrid fungal parasites into plankton ecology: research gaps and needs. Environmental Microbiology (2017).
5. Mycoloop: chytrids in aquatic food webs. Frontiers in Microbiology (2014).
6. Deep Sequencing of Subseafloor Eukaryotic rRNA Reveals Active Fungi across Marine Subsurface Provinces. PLOS ONE (2013).
7. Novel chytrid lineages dominate fungal sequences in diverse marine and freshwater habitats. Scientific Reports (2016).
8. Diversity and distribution of fungal communities in the marine sediments of Kongsfjorden, Svalbard (High Arctic). Scientific Reports (2015).
9. Adaptation to high salt concentrations in halotolerant/halophilic fungi: a molecular perspective. Frontiers in Microbiology (2014).