Trace metal content in annually banded scleractinian coral 'Porites lobata' across the northern Persian Gulf

Abstract

Concentrations of trace metals in skeleton growth bands of dominant scleractinian coral 'Porites lobata' in different years were investigated in Kharg and Hebourabi islands in the northern coast of the Persian Gulf. The highest average concentrations of metals respectively were Sr> Mg> Zn> Ba> Cu> U> Ni> Mn> Cr> Co> Pb> V> Cd in Kharg and Sr> Mg> Ba> Cu> U> Ni> Zn> Mn> Cr> Co> V> Pb> Cd in Hendourabi. The coefficient of variation percentages (CV%) of Cr, Mn, Zn, Ba, and Pb in Kharg and Cu and Ba in Hendourabi were more than 50%. Results of PCA analyses revealed that the levels of trace metals in Kharg were defined by three principle components: the first component (Mn, V, Pb, Zn, Ni and half of Mg, Cr and Co) corresponding to the past regional military conflicts and oil pollution, the second component (Sr, U, and Mg) corresponding to sea surface temperature (SST) changes, and the third component (Cr and Co) corresponding to other factors. The results of PCA analyses revealed that trace metals in Hendourabi were defined by two principle components including the first component (Co, Ni, Cr, Mn, and half of Ba) corresponding to annual precipitation changes and the second component (U, Zn, and Ba) corresponding to coastal constructions. The results showed that trace metal contamination in Kharg is higher than those of Hendourabi as a result of the oil exploration-related activities and war.

Keywords: Coastal constructions; Oil explorations; Oil pollution; SST; Trace metals.