Bio-mineralization in Skeletons of Some Elasmobranches From Susah and Dernah Coasts, Libya (Estimation Study Using Nano-Technique)

Skeletons of five elasmobranches specimens: [Galeorhinus galeus, Squalus acanthias, Rhinobatus rhinobatus, Raja clavata, and Taeniura grabata] were collected from Susah and Dernah coasts between March and April 2019, and scanned by XRF with Bruker S2 Ranger 2008, to study the bio-mineralization in their skeletons. Calcium carbonates CaCO3 ranged from 46.53% in Tope Shark to 50.69% in Dogfish. G. galeus peaked at its CaO (71.11%), compared to the nadir value of T. grabata (69.03%), the same species had a significant value of SO3 (16.2%), which dropped to 9.21% in R. clavata, which had the same number as the zenith of Phosphates (P2O5), that was lower than 8% in G. galeus, as lower as Silicates (SiO2) (7.80%). Also, R. clavata had maximized values of Magnesium, Aluminum, Iron, and Manganese oxide in this work till 0.32, 0.26, 0.42, and 0.89%, respectively. Tope sharks had the lowest sum of minerals 37.39%, insignificantly as much as the sum of the mineral in Dogfish’s skeleton (39.95%). Also, S. acanthias recorded a significant Ca/P ratio (9.53:1.00), compare to R. clavata (7.70:1.00). These analyses are useful to understand and following the physiology of bio-mineralization and bio-accumulation of minerals in marine organisms in Libyan coast.