AME 84:121-126 (2020)  -  DOI: https://doi.org/10.3354/ame01932

ABSTRACT: The northwestern Pacific Ocean and East China Sea (ECS) are frequently affected by typhoons during the summer period. To identify changes in production and consumption rates of phytoplankton (<20 and 20~200 µm) affected by Typhoon Maria (9-10 July 2018), 2 sampling periods were compared: a pre-typhoon cruise (4-9 July 2018) and a post-typhoon cruise (13-17 July 2018). Results showed that <20 and 20~200 µm phytoplankton production was 14- and 1.8-fold higher, respectively, in the post-typhoon period compared to the pre-typhoon. Accompanying this post-typhoon shift from pico- and nanophytoplankton to microphytoplankton, the consumption rate of microzooplankton on <20 µm phytoplankton was 11.6 mgC m^-3 d^-1 in the pre-typhoon period, and increased to 203.3 mgC m^-3 d^-1 after the typhoon. Furthermore, the ingestion fluxes were 4.9 and 8.0 mgC m^-3 d^-1 through mesozooplankton grazing on microzooplankton (ciliates and dinoflagellates) pre- and post-typhoon, respectively. Our findings show that organisms from the microbial food web (i.e. ciliates and dinoflagellates) may control the phytoplankton assemblage during the post-typhoon period of increased productivity, and thus represent an important trophic link between the classical and microbial food webs in the southern ECS.

KEY WORDS: Typhoons · East China Sea · Microzooplankton · Phytoplankton · Mesozooplankton · Microbial food webs