Chemical oceanography of the Arabian Sea: Part 1 - Hydrochemical and hydrographical features of the Northern basin

Abstract

Three water masses in the Arabian Sea have been identified from their physical and chemical characteristics: (i) water mass which originates in the surface layer and has high salinity,low oxygen and high pH ; (ii) water mass below it which has its origin in the Persian Gulf and has high salinity and low oxygen ; and (iii) deep water which has low salinity, low temperature,lower nutrients but high oxygen and PH. Two oxygen minima are observed the 1st at depthsbetween 100 and 400 m and the 2nd between 800 and 1500 m.Denitrification is observed at thelevel of the 1st oxygen minimum resulting in AN:AP ratio of 6:1 by atoms in water.