남해 연안 어류 양식장이 퇴적물의 유기물 분해와 영양염 플럭스에 미치는 영향

Abstract

Environmental impacts of fish farming in the southern coast of Korea, Kangjin Bay, on geochemical properties, total oxygen uptake in the sediment, and benthic nutrient fluxes were investigated. Geochemical properties (NH4+, PO43-, and HS-) in the pore water, total oxygen uptake, benthic nutrient fluxes at farm sites were higher than at the control sites. Due to formation of stratification at farm site water column during July, the HS- concentration at the farm site in July (6.7 mmol m-2) was 3.5 folds higher than in September (1.9 mmol m-2). Because of increased food input at the farm site in September, total oxygen uptake at the farm site was 2.1 folds higher in September (204.9 mmol m-2 d-1) than in July (98.8 mmol m-2 d-1). PO43- and HS- at the farm site in the pore water that mineralization rate of organic matter was stmulated in September, were not accumulated due to high concentration of FeOOH in the sediment. The dissolved inorganic nitrogen and phosphate fluxes at the farm site accounted for 325-530% and 257-1967%, respectively, of the N and P demands for primary production that indicate the tight benthic-pelagic coupling at the farm site. The results of this study suggest that the operation of fish farm could enhance TOU, and could repeat the vicious cycle that excessive nutrient fluxes cause eutrophication in the water column, and its enhance additional load of organic matter into the sediment, and finally benthic nutrient flux increase extremely.