Distinct acoustic survey as signatures of gas and oil seepage impacts on the coral reefs of Jubal area, Red Sea

Abstract

Bubble streams were detected from natural seep sites to the west of Jubal Island. They produced obvious signatures on acoustic images rising from the sea bottom to the water surface. The gas bubbles produced high backscatter, while the oily gas bubbles produced acoustic backscatter shadows. The oil coating the bubbles generated specific signatures, although all bubbles reverberated during the oftenness test. Bubbles were detected by the side-scan sonar and imaged by the ROV where the slicks were apparent on the water surface. The influence of the oil seepage on the coral reefs was clearly observed from the recorded images of the ROV. The long extension of hard and soft corals was determined from the analysis of the backscatter images.