Ortho-phosphate in the sea water of the South China Sea. Area II: Sabah, Sarawak and Brunei Darussalam

Abstract

The distribution of ortho-phosphate in the South China Sea off Sarawak, Sabah and Brunei Darussalam waters was studied in the SEAFDEC Interdepartmental Collaborative Research Survey : Area II. The samples were collected by M.V. SEAFDEC on 8 July to 3 August 1996 (pre monsoon period) and 1 to 24 May 1997 (post monsoon period). Seventy-nine stations were established in this study. The average concentration of ortho-phosphate of the pre monsoon period at 0-1 meter, 10 meter, 20 meter, 50 meter, 100 meter and 200 meter, 500 meter, 1000 meter and 1500 meter depth of the third survey cruise were 0.14 μM, 0.09 μM, 0.10 μM, 0.09 μM, 0.50 μM, 0.90 μM, 1.94 μM, 2.59 μM and 3.10 μM respectively. The average concentration of ortho-phosphate of the post monsoon period at 0-1 meter, 10 meter, 20 meter, 50 meter, 100 meter, 200 meter, 500 meter, 1000 meter and 1500 meter depth were 0.24μM, 0.28 μM, 0.20 μM, 0.25 μM, 1.15 μM and 2.27 μM, 4.13 μM, 5.19 μM and 5.41 μM respectively. The ortho-phosphate levels were low in the surface water and increase with depth. The results indicated that the deep water of the study area is very rich in phosphate.