Seabed geomorphology, substrate and benthic habitats informing long-term conservation of the Ascension Island Marine Protected Area

The Ascension Island Marine Protected Area (AI-MPA) is one of the largest areas of protected ocean, safeguarding a unique ecosystem in the South Atlantic Ocean. This study presents the first seabed geomorphology, substrate and benthic habitat maps of the AI-MPA, produced using high-resolution bathymetry data acquired by the British Geological Survey, the Royal Navy and the United Kingdom Hydrographic Office. Mapping combined a semi-automated approach with expert manual interpretation. The resulting datasets reveal a diverse range of previously unmapped volcanic, erosional, depositional and coastal features including submerged lava flows, rocky outcrops, ridges, submarine landslides, and sandy plains that support a rich variety of marine life seldom documented in such detail for remote mid-oceanic islands. These maps provide essential baseline data for monitoring of the marine environment and improve our understanding of geological features and processes around Ascension Island, supporting present and future marine conservation and management.