Some hydrological features of the eastern Arafura Sea and the Gulf of Carpentaria in August 1964

Abstract

Charts of the distribution of salinity, temperature, inorganic phosphate, nitrate nitrogen, oxygen, and particulate organic phosphorus, for the eastern Arafura Sea and Gulf of Carpentaria in August 1964 are presented. Interrelationships of these properties show that at least three water masses were identifiable in this month. Two were very low in nutrients (phosphate less than 0.20, nitrate less than 1.0 µg-atom/l) but differed in salinity (less than 33.00‰ and greater than 35.50‰). The third was high in nutrients (phosphate greater than 1.40, nitrate greater than 17 µg-atom/l) and had salinities between 33.80 and 34.70‰. The high nutrient water mass was derived from Banda Sea slope water at around 100-150 m, wlth its nutrients increased subsequently by biological action. The other two water masses were formed in the coastal region of West Irian and the Coral Sea. High surface oxygen saturation (139%) and accumulation of organic phosphorus in near-bottom waters of the eastern Arafura Sea were the result of an uplift of Banda slope waters, much earlier in the year than August. In the Gulf of Carpentaria, the August salinity temperature characteristics were formed by the southward drift along the eastern margin of Coral Sea waters, which increased in salinity and decreased in temperature by evaporation. Low salinity water of the previous summer occurred in August, only in the north-west of the gulf.