Changes of nitrogen and carbon budget by effluent of land-based aquaculture farm in the coastal area of Jeju, Korea

Abstract

Approximately 350 land-based aquaculture farms (LAF) have developed in Jeju, pollutions of coastal environment by the effluent discharge have recently become an issue. The effluent has high nutrient concentration and high organic matter content, which has a serious impact on the coastal ecosystem. We set up a demonstration area (850,000 m2) in the Handong coastal area (HCA) to identify the nitrogen (N) and carbon (C) budget. The amount of effluent from the LAF to the HCA is 780,000 m3/day. The average dissolved inorganic nitrogen (DIN) and particulate organic carbon (POC) concentrations in effluents are 72.86 &#61549 mol/L and 375.02 mg/m-3, respectively. The DIN and POC loads into HCA, calculated using concentrations and nominal flow of the effluents, amount to 796 and 293 kg/day, respectively. The amounts of dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) discharged into the HCA are 254 and 655 kg/day, respectively. Generally in Jeju, cultured water in the LAF uses coastal water and submarine groundwater (SG) at a ratio of 6:4. The amount of culture water flowing into the LAF from the HCA is 468,000 m3/day, and DIN, POC, DON and DOC are 52, 129, 45 and 473 kg/day, respectively. The N and C contents of effluent water are 9 and 2 times higher than that of the original cultured water, respectively. The N and C inputs to the coastal area are dominated by effluent (72% and 75%), followed by SG dischatent, which has a serious impact on the coastal ecosystem. We set up a demonstration area (850,000 m2) in the Handong coastal area (HCA) to identify the nitrogen (N) and carbon (C) budget. The amount of effluent from the LAF to the HCA is 780,000 m3/day. The average dissolved inorganic nitrogen (DIN) and particulate organic carbon (POC) concentrations in effluents are 72.86 &#61549 mol/L and 375.02 mg/m-3, respectively. The DIN and POC loads into HCA, calculated using concentrations and nominal flow of the effluents, amount to 796 and 293 kg/day, respectively. The amounts of dissolved organic nitrogen (DON) and dissolved organic carbon (DOC) discharged into the HCA are 254 and 655 kg/day, respectively. Generally in Jeju, cultured water in the LAF uses coastal water and submarine groundwater (SG) at a ratio of 6:4. The amount of culture water flowing into the LAF from the HCA is 468,000 m3/day, and DIN, POC, DON and DOC are 52, 129, 45 and 473 kg/day, respectively. The N and C contents of effluent water are 9 and 2 times higher than that of the original cultured water, respectively. The N and C inputs to the coastal area are dominated by effluent (72% and 75%), followed by SG discha