Distribution of phytoplankton biomass and nutrient concentrations in the Barents and Kara Seas during the 1st Korea-Russia Arctic expedition in August, 2000

Abstract

During the 1st Korea-Russia Arctic Expedition from 3 to 26 August, 2000 phytoplankton biomass and nutrient concentration were measured in the Barents and Kara Seas. Total of 57 surface samples were collected for the phytoplankton related measurements. Chlorophyll a (chl a) concentraitons were measured to investigate the relations between physico-chemical factors and phytoplankton biomass distribution. Chl a values ranged from 0.14 to 2.34 mg m-3 (mean of 0.65 ± 0.42 mg m-3) over the surface stations. The elevated values of the chl a concentrations (1.49∼2.34 mg m-3) were found in the southeastern Barents Sea near the Pechora River. Nanoplanktonic (<20 μm) phytoflagellates were the important contributors for the increase of the chl a. The nano-sized phytoflagellates accounted for more than 80% of the total chl a biomass in the study area. Mean chl a concentration in the Barents Sea (0.72 ± 0.57 mg m-3) was higher than in the Kara Sea (0.52 ± 0.45 mg m-3), but there was no big difference between two areas. Surface temperatures and salinities ranged from 4.1 to 11.7°C (mean of 8.8 ± 1.9°C) and from 23.8 to 32.5psu (mean of 30.3 ± 1.9 psu), respectively. The physical factors were not highly correlated with phytoplankton distribution. It is speculated that the insignificant correlation between phytoplankton biomass and physical factor was due to the same current which introduced similar water mass with higher water temperature and lower salinity into the study area. The mean values of major nutrients such as ammonia, nitrite, nitrate, phosphate, and silicate were 0.42 ± 0.31 μM, 0.10. ± 0.03 μM, 1.44 ± 1.03 μM, 0.35 ± 0.12 μM, 10.99 ± 3.45 μM, respectively. The relations between phytoplankton biomass and nutrient concentration were not close, indicating that the surface nutrient concentrations during the study seem to be controlled by other physical factors such as input of fresh water (i.e. dilution effects).