Unveiling Gas Seeps: A Dive into Water Column Data Analysis

Abstract Multibeam Echo Sounders (MBES) have significantly advanced underwater acoustic data analysis, allowing for the detection of various marine features. The enhanced capabilities of water column acoustic data analysis by MBES have played a crucial role in numerous research projects, including mapping methane gas flux and studying free gas release. This research aims to detect and quantify underwater gas seeps by leveraging the advanced imaging capabilities of MBES. The workflow involved displaying water column data, removing irrelevant echoes, applying amplitude threshold filtering, validating Local Intensity Maxima (LIM) values, exporting final coordinates, and calculating volumes using voxel-based methods. Results showed that higher frequencies (200 and 400 kHz) provided more detailed and accurate gas seep detection at 30 m depth, with average volumes of 25.972 m 3 and 31.050 m 3 , respectively. However, at a depth of 60 m, the 100 kHz frequency was more effective, with an average volume of 28.324 m 3 . These findings underscore the importance of frequency selection in MBES surveys for accurate gas seep detection and quantification. This study provides valuable insights into underwater gas seeps, enhancing our understanding of their impacts on the marine environment and the global carbon cycle. This study supports SDG 14 by advancing marine ecosystems, including the management of marine resources.