The Shatt al-Arab River: A nutrient salt and organic matter source to the Arabian Gulf

The distribution of dissolved reactive phosphate, nitrate and nitrite in the waters as well as total organic carbon, total phosphorus and Kjeldahl nitrogen in the sediments of the Shatt al-Arab Estuary and the NW Arabian Gulf were studied from November 1979 to April 1980. The Shatt al-Arab waters contain 0.18 to 0.70 µg-at P-PO _inf4 ^sup3– l^–1, 26.12 to 52.39 µg-at N-N0 _inf3 ^sup– l^–1 and 0.53 to 0.70 µg-at N-NO _inf2 ^sup– l^–1, indicating that this river should be considered a source of nutrients to the Arabian Gulf. It is concluded that most of the nitrate is supplied in dissolved form, while an appreciable amount of phosphate is absorbed to fine suspended particles and released at higher salinities. Total organic carbon in surficial sediments was found to vary between 0.14% and 0.96%. These rather low values are attributed to dilution by dust fallout, which is a major cource of sediments in this area.