Some aspects of the nitrogen cycling in the Arabian Sea

Abstract

Extensive observations made in the Arabian Sea establish it as one of the largest oceanic reducing sites accounting for approximately 1/3 of the global water column denitrification. Evidence for large short-term (seasonal) variations in the intensity of the oxygen-deficient conditions is provided by data on the nitrogen system as well as the activity of the electron transport system (ETS). The results imply a quick renewal of the oxygen-depleted waters. Denitrification in the Arabian Sea is unique in that it does not occur beneath centres of most intense seasonal upwelling; instead, it is most intense in offshore areas of relatively low primary productivity. Estimates of some important terms in the nitrogen cycling are evaluated.