鹿児島湾における微小プランクトン群集の季節動態

摘要

We evaluate seasonal changes in biomass, depth distribution and rate process of microbialplankton community in Kagoshima Bay. Micro-sized components dominated phytoplankton biomassthroughout the year and reached a maximum in April to June. Phytoplankton biomass at surface layersdecreased in summertime and increased again in autumn. Zooplankton biomass followed the seasonalpattern of phytoplankton with a smaller temporal fluctuation. Micro-sized components dominated zoop-lankton biomass and appeared near surface throughout the year. Dilution experiments demonstrated thatmore than 70% of phytoplankton production was grazed by microbial predators during October to No-vember. These results suggest that phytoplankton production transfers to grazing food web or exports todeep layers during winter to summer and contributes to carbon flow of microbial food web in autumn.