Bacterial Abundance and Production in July 1997 in the vicinity of Tokdo, East Sea

Participating in a multi-disciplinary oceanography program in July 1997 in the vicinity of Tokdo, we studied the distributions of bacterial abundance and production along with those of phytoplankton and heterotrophic nanoflagellates. In the euphotic zone, chlorophyll a (chl a) concentrations ranged from 0.14 to 0.52 ${\mu}$g 1$^{-1}$. Bacterial abundance in the euphotic zone (0.12-0.21 ${\times}$ 10$^9$ cells 1$^{-1}$) in the study area was quite lower than that expected from the observed chi a concentration in the marine environment. The low bacterial abundance seemed to be due to active grazing pressure on bacteria. The fraction of primary production utilized by bacteria was also low(8-12%). Interestingly, surface water temperatures were love. at stations near islands compared to an offshore station located between Ulleungdo and Tokdo and the highest values of bacterial production and chi a were found at stations near islands, strongly indicating island mass effects.