Abstract
Analysis of coral reef species enables characterization of the coral reefs and the degree to which human activities influence the reef composition. Geochemical characteristics, X-ray diffraction, and natural radionuclides analyses of four common coral reef species representing the branching and massive forms were conducted at the three areas under threat ( Quseir Harbor, Safaga Harbor, and El-Esh area) along the Red Sea coast. Branching recorded higher carbonates and lower organic matter than the massive forms. Stylophora pistillata at Safaga Harbor and El-Esh area and Acropora humilis at Qusier Harbor recorded the highest carbonate percentages ( 96.88, 96.24, and 96.89%, respectively) meanwhile Platygyra daedalea at Safaga Harbor recorded the highest organic matter contents ( 5.07 and 4.91%). The highest Ca contents were observed in S. pistillata and Porites solida ( 65.87 and 64.87%), the highest Mg was in Acropora humilis and P. daedalea ( 1.06 and 0.88%) at Qusier Harbor, whilst the highest Sr was in S. pistillata and P. daedalea at Safaga Harbor. Then highest value of 226Ra recorded in A. humilis and P. solida ( 71 +/- 3.5 Bq/kg and 63 +/- 3.1 Bq/k) and Th-232 in S. pistillata at El-Esh area may attribute to petroleum exploration activities. A. humilis and P. daedalea at Safaga Harbor recorded significant high K-40 values ( 505 +/- 30 and 472 +/- 13 Bq/kg, respectively) relative to the other localities. The low Ca and High Sr as well as the highest averages of Th-232 and K-40 at Safaga Harbor indicated that the coral reef communities were highly affected by the terrestrial inputs from phosphate shipments.