Distribution of organic carbon in sediments from the Arabian Sea

Abstract

Many earlier studies on the distribution of organic carbon in the Arabian Sea, sediments have projected contradictory opinions on the factors favouring accumulation and preservation of organic carbon in the Arabian Sea. An attempt is made to revaluate the role of various sedimentary parameters on the surficial distribution of organic carbon in the Arabian Sea. The revaluation identifies two regional bands of organic-rich sediments: one along the slope of the Arabian Peninsula and the other along the western slope of India. The organic carbon distribution mirrors the surface productivity - high in the peripheral portions and low in the open ocean suggesting it mainly from marine origin. A perfect coincidence of organic enrichment on the slopes with the oxygen minimum zone (150 - 150 m) clearly demonstrates the influence of anoxixc waters on organic enrichment. Bottom water anoxia, though a principal factor for organic enrichment on the slopes, and its interplay with other depositional parameters cumulatively determines the 'degree of preservation' and fix the location of organic enrichment along the slopes