Sedimentation rate and bioturbation in the Arabian Gulf

• Published in: Environment international 1998-01, Vol.24 (1), p.23-31
• Main Authors: Al-Ghadban, A.N., Abdali, F., Massoud, M.S.
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Marine; Marine and continental quaternary; Pollution, environment geology; Surficial geology
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/S0160-4120(97)00118-9

The Arabian Gulf is a shallow marginal sea of the Indian Ocean. It is a semi-closed basin which extends for nearly 1000 km from Shatt Al-Arab, the nexus of the Tigris, Euphrates, and Karun Rivers in the northwest, to the Strait of Hormuz in the southeast, and covers a surface area of about 239 000 km 2. In addition to Shatt Al-Arab, river inflow into the Gulf occurs primarily on the Iranian northeastern side, the estuary of major rivers such as the Hendijan, the Rud Hilleh, and the Mand. The bathymetry of the Inner Sea basin shallows to the northwest and to the west coast (Reynolds 1993), whilst the basin floor is asymmetric with its axis lying close to the Iranian Coast. It slopes gradually from the shallow deltaic northern part to deeper waters in the south, with the depth rarely exceeding 100 m (only 36 m on average). It is a region of great interest to environmental scientists. It is bordered by rock sequences which contain the richest oil deposits in the world, and one-third of world oil energy is transported through this body of water. Despite the tremendous stress exerted by oil production and transportation, this area was also a subject of man-made pollution. Between 19 and 30 January 1991, an estimated 10.8 million (1.7 Mm 3) barrels of oil were spilled deliberately by Iraqi troops in the Gulf waters, mainly from seven abandoned tankers and the Al-Ahmadi Sea Island terminal near the coast of Kuwait, in addition to smaller discharges from the Iraqi Mina Al-Bakr terminal and nearby sunken tankers, and the Saudi Ras Al-Zur refinery at Mina Sa'ud (Tawfiq and Olsen 1993). It is also estimated that 8 million (1.3 Mm 3) barrels of oil fallout from the smoke plumes of the 727 oil well blowouts and fires in Kuwait oil fields, started in late February 1991 by departing Iraqi troops, were deposited in the Gulf marine environment (Al-Rabeh et al. 1992; Literathy 1993). The airborne fallouts, which contained oil-combustion products, particularly ash, and trace metals originally present in the burnt crude oil, doubled the size of the oil slick and made the event the largest of its kind in the history of marine pollution (Reynolds 1993). As part of the efforts exerted by the international community to assess the impact of the Kuwait oil slick, an integrated programme was planned and sponsored by the Regional Organization for the Protection of Marine Environment (ROPME), the Intergovernmental Oceanographic Commission (IOC), the United Nations Environmental Progra