Spatial and seasonal variations in suspended particulate matter concentration and composition in the Persian Gulf: From dust deposition and sediment resuspension to biological production in the regulation of the particulate trace elements

The present document is intended to fill the knowledge gap on spatiotemporal variation of suspended particulate matter (SPM) concentration and composition by collecting samples from 26 stations during two contrasting seasons of summer and winter. The horizontal distribution of surface SPM is characterized by hotspots (up to 4.0 mg/l) along the river estuaries which sharply declined to <1 mg/l in the offshore region. The average SPM concentration for surface, 25 m, and near-bottom decreased from summer to winter by a factor of 1.1, 1.3, and 1.7, respectively. In the offshore region, the particle composition was dominated by particulate organic matter which accounted for 66 % of bulk SPM. The concentration of opaline silica increased from summer to winter presumably from the bloom of diatoms. The concentration of particulate trace elements in winter decreased in the order of Fe >> Ba > Mn approximate to Zn > Ni approximate to Cr >> Pb > Cd. The non-crustal portion is the predominant fraction for most trace metals and shows enrichment relative to the upper continental crust, local soil background, and deposited dust that is highest for Cd and lowest for Mn.