US EPA

542810 

Journal Article 

Bio-mineralization processes and heavy metal incorporations in the scleractinian coral skeletons, Red Sea, Egypt 

Dar, MA; Mohammed, TA 

2006 

32 

87-104 

The bio-mineralization processes of the heavy metals in the skeletal frameworks were studied in eight living coral species belonging to three dominant forms; branching, massive and encrusting corals collected from three environmental and anthropogenic different localities. The organic matrix (1) of each spacemen including; mucus, zooxanthellae and organic tissue was sequestrated from the underlying aragonite skeleton (S) in the laboratory, subsequently; the metal contents in the organic matrices and the corals skeletons were measured separately. The heavy metals mineralization inside the skeletal framework of scleractinian corals is controlled essentially by; the exposing surface area, the bulk density, the organic matrix thickness and the continuality of the supplying sources. Fe, Zn, Ni and Pb concentrations are pronouncedly high in the organ matrices; their occurrences in the tissues are a function to their contents in the underlying skeletons which mean that the metals increasing in tissue supervened by the same increasing in the skeletons. Mn, Cu and Cd are not belonging this role, they behave mineralization mechanism in the coral skeletons from the surrounding seawater rather than the incorporation from the overlying organic matrix. T/S ratios illustrated distinctly the metal quantities that can mineralize in the skeletal framework of the corals. T/S ratios in the branching corals are higher than those in the massive and encrusting corals. The increasing ratio deals to that the incorporated metals in the organic matrices are much higher than the mineralized in the skeletal frameworks, subsequently, the excess metals are rejecting to the surrounding seawater according to the following the sequence; Fe > Pb > Zn > Cu.