Phytoplankton blooms and associated variations in transparent exopolymer particles in Tokyo Bay

Abstract

Annual study was conducted in Tokyo Bay to investigate the influence of anthropogenic influx on phytoplankton community and concentrations of transparent exopolymer particles (TEP). Enhancement of TEP as a result of high phytoplankton biomass was observed with an empirical relationship between TEP and chlorophyll a. Of the phytoplankton groups derived by the CHEMTAX analysis using pigment composition, diatoms invariably dominated the phytoplankton community. Multivariate analysis between TEP and chlorophyll a of different algal groups indicated the major influence of diatoms and raphidophytes on TEP concentration. Laboratory experiments conducted with Skeletonema costatum and Heterosigma akashiwo confirmed the higher contribution of H. akashiwo to dissolved organic matter production and subsequent TEP concentrations. In addition to phytoplankton biomass and composition, growth stage of the organisms appears to be an important factor controlling TEP concentrations in the aquatic ecosystems. © 2002, The Japanese Society of Fisheries Science. All rights reserved.