Fungal parasitism on diatoms alters formation and bio-physical properties of sinking aggregates



: Klawonn Isabell, Van den Wyngaert Silke, Iversen Morten H, Walles Tim JW, Flintrop Clara M, Cisternas-Novoa Carolina, Nejstgaard Jens C, Kagami Maiko , Grossart Hans P

Publisher: NATURE PORTFOLIO

: 2023

: Communications Biology

: COMMUNICATIONS BIOLOGY

: COMMUN BIOL

:  206

: 6

: 1

: 14

DOI: https://doi.org/10.1038/s42003-023-04453-6

: https://www.nature.com/articles/s42003-023-04453-6

: https://research.utu.fi/converis/portal/detail/Publication/179136857


Phytoplankton forms the base of aquatic food webs and element cycling in diverse aquatic systems. The fate of phytoplankton-derived organic matter, however, often remains unresolved as it is controlled by complex, interlinked remineralization and sedimentation processes. We here investigate a rarely considered control mechanism on sinking organic matter fluxes: fungal parasites infecting phytoplankton. We demonstrate that bacterial colonization is promoted 3.5-fold on fungal-infected phytoplankton cells in comparison to non-infected cells in a cultured model pathosystem (diatom Synedra, fungal microparasite Zygophlyctis, and co-growing bacteria), and even >= 17-fold in field-sampled populations (Planktothrix, Synedra, and Fragilaria). Additional data obtained using the Synedra-Zygophlyctis model system reveals that fungal infections reduce the formation of aggregates. Moreover, carbon respiration is 2-fold higher and settling velocities are 11-48% lower for similar-sized fungal-infected vs. non-infected aggregates. Our data imply that parasites can effectively control the fate of phytoplankton-derived organic matter on a single-cell to single-aggregate scale, potentially enhancing remineralization and reducing sedimentation in freshwater and coastal systems.Fungal parasites are found to effectively control the fate of phytoplankton-derived organic matter, potentially enhancing remineralization and reducing sedimentation in freshwater and coastal systems.

Last updated on 2024-26-11 at 23:23