Particulate organic carbon and particulate humic material in the Arabian Sea

Variations in particulate organic carbon (POC) and particulate humic materi al (PHM) were studied in winter (February-March 1995) and intermonsoon (Apr il-May 1994) seasons in the Arabian Sea. Higher levels of POC were found in the north than in the southeastern side of the Arabian Sea close to the co ast caused by higher biological production as a consequence of winter overt urning. The PHM showed significant aggregation between 100 and 200 m during winter and was negligibly low towards north and relatively more towards so uth indicating accumulation of humic material. In contrast, PHM occurred in north than in south in,intermonsoon. The north south trends could be seen in POC and PHM along 64 degrees E in the Arabian Sea. The POC levels were l ower in the Central Arabian Sea in winter, than in intermonsoon, its concen tration increasing slightly towards north in accordance with the microzoopl akton and bacterial production. The abundance of PHM seems to be related to the intensity of biological activity, the nature of organic material and t he spatial and temporal variations in biochemical conditions.