Distribution of water masses and variation of nutrients in the coastal areas of Gangwon Province of the Korean East Sea from 2008 to 2012

Abstract

The distribution of water masses and variation of nutrients according to the change of seasons and locations were investigated 4 times per year in the coastal areas of Gangwon province of the Korean East Sea from 2008 to 2012. The surveys of the physico-chemical parameters (temperature and salinity) and nutrients (NO2-N, NO3-N, NH4-N, PO4-P, and SiO2-Si) were carried out at 6 locations (Goseong, Sokcho, Yangyang, Gangneung, Donghae and Samcheok). The water masses included in the study area were divided into 4 groups 1) Tsushima Surface Water (TSW), 2) Tsushima Middle Water (TMW), 3) North Korean Cold Water (NKCW), and 4) East Sea Proper Water (ESPW). The distribution of water masses was affected by the change of season. In February, surface water was derived from the TMW. The TSW was not observed in May, but only observed in August. In November, as the influence of the TSW weakened, that of the NKCW strengthened. The average concentration of nitrate for 4 years at surface was 12.322 μM and bottom was 15.700 μM. The average concentration of phosphate for 4 years at surface was 1.086 μM, and bottom was 1.331 μM. Silicate for 4 years at surface was 20.706 μM, and bottom was 1.331 μM. The annual average concentration of nutrients at surface showed the highest concentration in 2009. The annual average concentration of nutrients at bottom increased sharply since 2010, and showed the highest concentration in 2011. The seasonal average concentration of nutrients at surface showed the highest concentration in February, and gradually decreased thereafter. On the other hand, the seasonal average concentration of nutrients at bottom increased since February, and showed the highest concentration in August. The average surface concentrations of nutrients at various locations showed a similar concentration, but showed the lowest at Samcheok.