On the Pollution Caused by Organic Materials in Chinhae Bay,Korea

In August 1989, oxygen deficient conditions of bottom waters occurred in the Chinhae Bay together with a steep pycnocline. Dissolved oxygen contents were lower than 1 ml/l from 3 m depth in the inner Masan Bay and from 10 m depth in the outer Masan Bay. in Kohyonsong Bay, surface salinity was about 29%_° and an oxygen deficient condition occurred in the bottom waters. Near Somodo Island, surface waters containing more than 30 μ/l of chlorophyll α and over 50 μmol/l of nitrate could be distinguished. in Masan Bay ammonia and phosphate concentrations increased with increasing depth suggesting the active degradation of organic materials in the bottom waters and leaching from sediments.

In Kohyonsong Bay, nitrate contents ranged from 1.9 to 5.4 μmol/l in the surface waters and subsurface maximum of chlorophyll α could be observed. ETS activity was 286.1 μl O₂/l-h in the surface waters of Masan Bay and respiratory oxygen consumption is likely to proceed at a rate of 1320 ml O₂/m²-d in the bottom waters of this bay. Primary productivity was 15.60 gC/m²-d in the inner Masan Bay and 0.75 gC/m²-d in Kohyonsong Bay.

In Masan Bay, amino acids content in the sinking materials collected by the sediment trap deployed at the bottom layer was 264 mgC/m²-d. This amount is equivalent to 6.8% of the amino acids produced in the water column by primary production. in Kohyonsong Bay 95 mg/Cm²-d of amino acids was collected corresponding to 50.8% of amino acids produced in the water column. in Kohyonsong Bay large faecal pellets produced in shellfish farms were easily settled in the sediment because of the weak current regime.