Physical Controls on Oxygen Distribution and DenitrificationPotential in the North West Arabian Sea
Bastien Y. Queste1, Clément Vic2, Karen J. Heywood1, and Sergey A. Piontkovski3
1Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, UK
2Department of Ocean and Earth Sciences, University of Southampton, Southampton, UK
3College of Agricultural Marine Sciences, Sultan Qaboos University, Muscat, Oman
At suboxic oxygen concentrations, key biogeochemical cycles change and denitrification becomes the dominant remineralization pathway. Earth system models predict oxygen loss across most ocean basins in the next century; oxygen minimum zones near suboxia may become suboxic and therefore denitrifying. Using an ocean glider survey and historical data, we show oxygen loss in the Gulf of Oman (from 6–12 to <2 μmol/kg1) not represented in climatologies. Because of the nonlinearity between denitrification and oxygen concentration, resolutions of current Earth system models are too coarse to accurately estimate denitrification. We develop a novel physical proxy for oxygen from the glider data and use a high-resolution physical model to show eddy stirring of oxygen across the Gulf of Oman. We use the model to investigate spatial and seasonal differences in the ratio of oxic and suboxic water across the Gulf of
Oman and waters exported to the wider Arabian Sea.
Taxonomic Composition and Seasonal Changes of Fish Larvae
Assemblages in Coastal Waters of Muscat, Sea of Oman
1Nadir M. Al-Abri, 2Sergey A. Piontkovski, 3Mahnaz Rabbaniha, 2Khalid Al-Hashmi and 1Tatyana Chesalina
1Marine Science and Fisheries Center, Muscat, Sultanate of Oman
2College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O. Box 34, Al-Khod 123, Sultanate of Oman
3Iranian Fisheries Research Organization, P.O. Box 14155-6116, Tehran, Iran
Fish landings and Oman shelf area
Sergey A. Piontkovski1, H.E. Hamed S. Al-Oufi2, and Nadir M. Al-Abri2
1Sultan Qaboos University, College of Agricultural and Marine Sciences, Dpt. of Marine Science and Fisheries.
2 Ministry of Agriculture and Fisheries Wealth. PO 467, Muscat 113.
Sultanate of Oman.
Data from five field surveys carried out along the shelf in the 20-250m depth range and historical data on artisanal fishery were analyzed. A positive linear relationship between the demersal fish biomass and the shelf area was pronounced for a certain (intermediate) stratum only: 50-100m. No statistical link was found for the strata above it (25-50m) and beneath it (100-150m and 150-250m). The pronounced one was associated with the low boundary of the oxygen minimum zone impinging on the shelf. Annual landings of demersal fishes in the region with the largest shelf area exceeded landings in the region with the smallest area by as much as 1.6 times. The ratio of small pelagic to demersal fish landings decreased as a factor of 10, from small to large shelf areas.
Fish landings; Arabian Sea; continental shelf; oxygen minimum zone; Oman