Secretion of sulfated fucans by diatoms may contribute to marine aggregate formation

Microalgae produce copious amounts of structurally diverse polysaccharides, some are bound within cells and cell walls, while others secreted into the surrounding seawater. A fraction polysaccharides assembles particles promoting aggregation in turn formation aggregates increases export carbon deep ocean via sinking. However, specific contributing to particle remain unknown. Here, we studied microalgae polysaccharide composition a system reduced complexity consisting lab grown monospecific cultures centric diatom species Thalassiosira weissflogii Chaetoceros socialis. We followed abundance dynamics five types dissolved particulate organic matter (DOM POM) for two weeks. Polysaccharides were detected using monoclonal antibodies (mAbs) ?-1,4-mannan, ?-1,4-xylan, arabinogalactan, fucose-containing sulfated (FCSP) epitopes. Additionally, glycan all samples was analyzed by monosaccharide analysis. The time series revealed partition differently between pools. ?-1,4-xylan ?-1,4-mannan mainly present POM, possibly as wall polymers, FCSPs found both DOM POM. data showed that main component diatoms polysaccharide, which accumulated over time. Roller tank experiments used induce aggregate finding FCSP transitioned from POM under aggregating conditions. These results suggest diatom-secreted involved aggregates, promote particles, potentially export.