Gulf of Mexico soundscape dominated by anthropogenic contributors

The Gulf of Mexico is a biodiversity hotspot, encompassing diverse habitats ranging from coral reefs to deep-sea seeps and supporting an array of marine species. Anthropogenic activity in the region, however, is widespread, with over 3000 actively drilling oil rigs including associated seismic exploration surveys, and over 10 international ports supporting extensive marine traffic. These activities generate underwater noise, impacting marine species that rely on sound for daily life functions. In this study, we analyzed sound levels from long-term passive acoustic recordings at eight sites across the Gulf to evaluate the influence of anthropogenic activity on the soundscape. A source separation analysis was conducted on hourly spectra to examine prominent subcomponents of the soundscape. Specific frequency bands were extracted to identify variations in sound levels associated with airguns, vessels, and wind noise. Excess noise levels were computed to determine increases in noise from modeled pre-industrial levels. Results reveal that seismic exploration airgun signals were a dominant contributor, significantly altering the low-frequency acoustic environment for the majority of the sites with noise levels at some sites reaching excess levels of over 40 dB. This research underscores the critical role of measuring underwater sound levels in assessing the ecological impacts of human activities on marine environments.