Planktonic fungi are, arguably, the last major taxonomic group that has been neglected from biological oceanography studies. We are barely beginning to understand their abundance, distribution and role in ecological and biogeochemical cycles in the open ocean. An initial study, based on metabarcoding at the Bermuda Atlantic Time-series Study site, provided many interesting insights regarding taxonomy and potential functionality, but at the same time raised even more questions owing to the lack of abundance and biomass data. Here we build on that prior work, presenting microscopy data of multicellular fungal plankton from the surface, deep chlorophyll maximum, 200 m and 300 m. Our results demonstrate a maximum of multicellular fungal plankton at upper epipelagic, ranging in morphology from long, isolated hyphae to large, complex colonies, close to a millimeter in size. These large colonies were often associated with dead, visible, organic particles or natural semitransparent aggregates, but sometimes they were observed without a foreign base for development. Abundance and carbon biomass profiles of the fungal plankton were found to be similar in range to those of the heterotrophic eukaryotes. Biomass and nature (developed hyphae vs yeast/pseudohyphae) of the fungal plankton changed with the months and hydrography, which would indicate a seasonal response of the fungal community. These results are compared to those from previous metabarcoding data, for a better understanding of the potential ecological profiles and roles of the fungal plankton in the oligotrophic oceans.

Primary Presenter: Leocadio Blanco Bercial, Bermuda Institute of Ocean Sciences - Arizona State University (leocadio_blanco@hotmail.com)

Authors:

Leocadio Blanco-Bercial, Bermuda Institute of Ocean Sciences - Arizona State University  (leocadio@asu.edu)

Jessica Godfrey, Bermuda Institute of Ocean Sciences - Arizona State University  (jessica.godfrey@bios.edu)