1Seikai National Fisheries Research Institute, Taira, Nagasaki 851-2213, 2Nagasaki Prefectural Institute of Fisheries, Taira, Nagasaki 851-2213, Japan
The dynamics of transparent exopolymer particles (TEP) and environmental factors such as water temperature, salinity, chlorophyll a concentration (Chl a), and phytoplankton composition (abundance) were investigated in Isahaya Bay, Kyushu Island, Japan, in spring and autumn, 2007-2008. Phytoplankton composition was dominated by diatoms, particularly Chaetoceros spp., Eucampia zodiacus, Leptocylindrus danicus and Skeletonema spp., during most of the investigation periods. TEP concentration was significantly correlated with water temperature, salinity, Chl a concentration, and phytoplankton abundance, especially diatoms. However, the peak of TEP concentration did not always match the peak of phytoplankton bloom; indeed, it tended to occur in the senescent phase of the bloom. These results indicate that the dynamics of TEP in Isahaya Bay are closely related to the abundance of mainly diatoms, and the complexity of TEP dynamics may be affected by the variations in TEP production by differences in growth and physiological state of diatoms under changing environmental conditions.