SEAMAP: targeted underway bathymetry for mapping uncharted seamounts and assessing their role in the ocean system

Seamounts number in the hundreds of thousands across all ocean basins and constitute a fundamental component of the ocean floor. They provide constraints on intraplate magmatism, mantle melting processes, lithospheric stress and flexure, and the evolution of oceanic plates. At the same time, seamounts are hotspots of biodiversity, and their morphology modifies ocean circulation and mixing, further influencing benthic ecosystems. Addressing these aspects requires high-resolution bathymetric mapping, yet most seamounts inferred from satellite-derived gravity data have never been directly surveyed.

The German marine research community contributes to systematic seafloor mapping during transits of the large German research vessels through the underway research-data project coordinated within the German Marine Research Alliance (DAM). While this approach steadily improves coverage and contributes to international efforts such as Seabed 2030, the scale of the remaining mapping gap of about 75% motivates complementary strategies that increase scientific return without substantially increasing ship time. Within the SEAMAP project, we pursue a collaborative approach in which research vessel transits are actively planned to intersect previously uncharted seamounts, with minimal impact on cruise logistics and primary scientific objectives. The goal is to link underway data acquisition to active research questions in geodynamics and ocean sciences.

We present initial results from SEAMAP. Modified transits have so far been planned for five research cruises, resulting in new multibeam bathymetric coverage of approximately 80 previously unmapped seamounts across a range of tectonic settings and plate ages. The acquired data are being integrated into studies addressing intraplate volcanic construction, machine-learning-based bathymetry prediction and validation, and flow–topography interactions, including enhanced mixing and turbulence in seamount wakes. In parallel, SEAMAP supports rapid data availability by integrating new bathymetric products into the harmonized data streams for German research vessels established by DAM. These results illustrate how targeted seamount mapping during transit legs can efficiently improve seafloor coverage while supporting interdisciplinary ocean science on the role of seamounts within the Earth system.