Evaluation of the mycobiome of ballast water and implications for fungal pathogen distribution

Marine transport has the potential to alter the geographic range of microorganisms through ballast water movement. Recent culture-independent studies investigated the bacteriome of ballast water, but no prior studies have examined the mycobiome. Here were examined 60 ballast and harbor samples from 4 major ports and 5 ocean samples using culture-independent techniques to determine (1) the composition of harbor and ballast water mycobiomes; (2) if ballast contained human and environmentally relevant fungal pathogens; and (3) the potential risk of introduction to coastal ecosystems. Results indicate that ballast water and harbor water contain a diverse mycobiome and that ballast water may contain fungal taxa that are relevant human and marine fish pathogens. Fungal genera were identified that contain known coral and coastal plant pathogen species; however, species-level identification of these potential pathogens could not be conclusively resolved. Ballast and harbor mycobiomes contained similar taxa, suggesting that environmental filtering may not inhibit the spread of fungal taxa between these ecosystems. This study highlights the potential risks of ballast movement and suggests further research of the ballast mycobiome is needed.