Primary production and organic carbon budget in Lake Soyang

 

Kim, Bomchul1, Gilson Hwang2 and Dong-Sup Kim3

1Dept. of Environmental Science, Kangwon National Univ. Chunchon, 200-701

2Rural Development Corporation, Rural Research Center

3Korea Water Resources Corporation, Water Resource Research Institute

 

 

Abstract

 

The organic carbon budget was surveyed to clarify the contribution of phytoplankton  primary production in Lake Soyang from 1986 to 1995. Autochthonous organic carbon was calculated from the primary production of phytoplankton. Allochthonous organic carbon was analyzed by measuring COD input from watershed and discharge from fishfarms in the lake. Outflowing organic carbon from lake were measured by COD at the outlet of the lake. Daily primary production ranged 4 5,357 C m-2 day-1, and it was higher in the rainy season. But, it was only 2 3 month in a year that primary production over the criteria of eutrophic lake, 1,000 C m-2 day-1. Both autochthonous and allochthonous loading of organic carbon were highest in the rainy season from June to September. The inorganic nutrients and organic carbon input with storm runoff stimulate the phytoplankton production in this period. The contribution of organic carbon loading from fishfarms and autochthonous production accounted for 2 7% and 35 70% of the annual organic carbon loading, respectively. Autochthonous production in Lake Soyang contributed not so much compare with the other artificial reservoirs in Korea