High-frequency sampling of microbial eukaryotes in the Baltic Sea

Heterotrophic nanoflagellates (HNF) are a key component of the microbial food web (MFW), facilitating nutrient recycling and energy transfer in aquatic ecosystems. They have been largely considered as typical bacterivores, but they can be also omnivorous (feeding on prokaryotes and other eukaryotes) and predatory grazers (feeding on other eukaryotes). This study investigates HNF community composition and dynamics in the Baltic Sea from spring to autumn, focusing on their functional roles within the MFW. To follow rapid changes in microbial communities and match flagellate duplication times, we carried out two high-frequency sampling campaigns during spring (March-May) and autumn (September-November) phytoplankton blooms.