Choon Weng Lee, Isao Kudo, Mitsuru Yanada & Yoshiaki Maita (2001) Bacterial 
abundance and production and their relation to primary production in Funka Bay. 
Plankton Biology and Ecology 48(1): 1-9

Abstract: Abundances of bacteria, phototrophic picoplankton and heterotrophic and 
phototrophic nanoflagellates in Funka Bay were measured on five occasions (from 
June to November) in a water column with a summer thermocline. Nutrient 
concentrations (nitrate, nitrite, ammonium and phosphate) in the euphotic layer were 
low whereas chlorophyll-a concentrations fluctuated from 0.3 to 1.2 µg l-1. Bacterial 
abundance ranged from 3.1 x 105 to 1.1 x 106 cells ml-1, whereas the heterotrophic 
nanoflagellate (HNF) abundance ranged from 4.2 x 102 to 3.5 x 103 cells ml-1. In the 
euphotic layer, cyanobacterial abundance ranged from 1.3 x 104 to 2.9 x 105 cells ml-1. 
Bacterial abundance correlated significantly with both chlorophyll-a concentration 
and HNF. Bacterial growth rates in the euphotic layer were estimated using a dilution 
culture method, and ranged from 0.024 to 0.048 h-1. Bacterial net production ranged 
from 8.7 to 23.9 mg C m-3 d-1, Net primary production measured in this study ranged 
from 1.1 to 52.5 mg C m-3 d-1, We found that for the euphotic layer, integrated 
bacterial net production (460-780 mg C m-2 d-1) was higher than integrated net 
primary production (220-610 mg C m-2 d-1). The disparity between bacterial net 
production and net primary production allowed us to suggest that primary production 
may not be adequate to support bacterial carbon demand, and that other sources of 
organic matter were also used.