Calcite and aragonite saturation States of Kamaran strait surface seawater, Yemen: summer time

Abstract

Surface seawater samples from Kamaran Strait of Yemen were collected for physical and chemical parameter determinations. This work reports the results of air and surface seawater temperature, salinity, pH, and total alkalinity measurements. The air temperature ranged from 29.9°C to 36.5°C with an average value of 31.5 ± 1.5°C, whereas the seawater surface temperature ranged from 34.0°C to 36.0°C with a mean value of 34.5 ± 0.5°C. The salinity was observed to be high, ranging from 38.03 to 38.81 with an average value of 38.45 ± 0.22. The pH ranged from 7.74 to 8.27 with a mean value of 8.11 ± 0.10. The total alkalinity was found to range from 2.3860 to 2.5000 meq L−1 with an average value of 2.4288 ± 0.0351 meq L−1. The result of the study showed that there was a negative correlation between the pH and surface seawater temperature and salinity. The surface seawater of the Kamaran Strait was found to be several fold supersaturated with respect to calcium carbonate. The measured percent degree of saturation ranged from 454% to 668% with respect to calcite and from 246% to 361% with respect to aragonite. The lowest value of supersaturation with respect to both calcite and aragonite were found in front of as-Salif port, where human and developmental activities are intensively increased. The visual inspection of coral reefs distribution and their intensity were obviously observed in areas of high value of supersaturation with respect to both minerals, high transparency of seawater column, and low human activities. Further studies are needed to investigate the occurrence, distribution, and mineralogy of corals and the effects of physical and chemical parameters upon their growth in the region.