San Diego, California – A groundbreaking discovery in ocean floor mapping has unveiled an astonishing 100,000 seamounts across the world, thanks to data collected by NASA’s Surface Water and Ocean Topography (SWOT) satellite. This new detailed cartography represents a significant leap in our understanding of underwater topography, far surpassing previous estimates of 44,000 known seamounts.
For decades, scientists have been striving to create comprehensive maps of the ocean floor, which makes up more than 70% of our planet. The recent release of one of the most detailed seafloor maps ever developed marks a pivotal moment in marine exploration. By utilizing data obtained from NASA’s SWOT satellite, researchers have exposed underwater landscapes that were previously hidden from human knowledge.
David Sandwell, a geophysicist from the Scripps Institution of Oceanography who has been utilizing satellite data to map the seafloor since the 1990s, underscores the significance of this breakthrough. The SWOT satellite represents a crucial advancement in our ability to map the ocean floor. Their findings, published in Science in December 2024, showcase the extraordinary precision of this new mapping technology.
The SWOT satellite, a joint project between NASA and the French space agency CNES, covers around 90% of the planet every 21 days. This frequent revisiting enables the satellite to detect subtle centimeter-scale variations in sea surface height caused by underlying seafloor features. Utilizing the technology behind this, geological formations like seamounts, which have greater mass than their surroundings, create slightly stronger gravitational pulls that result in measurable bumps on the sea surface.
Previously, ocean observation satellites could solely detect massive seafloor formations, such as seamounts taller than one kilometer. However, advancements in modern space missions now allow the detection of features less than half that height, significantly expanding our underwater vision.
The detailed mapping of the seafloor reveals various distinct geological formations that enrich our understanding of Earth’s underwater landscapes, such as seamounts, abyssal hills, continental margins, fracture zones, and deep ocean trenches. The seamounts, in particular, serve as underwater oases, concentrating nutrients on their slopes and attracting a diverse array of marine organisms. They also impact deep-sea circulation patterns and create unique habitats in less hospitable areas of the ocean floor.
Yao Yu, an oceanographer at Scripps Institution of Oceanography and the lead author of the study, emphasizes the ecological importance and abundance of abyssal hills, which form in parallel bands due to tectonic plate movements. The color patterns on the detailed maps aid scientists in interpreting the complex underwater landscapes across vast oceanic regions, with areas of reduced gravity and increased gravity denoting depressions and elevated structures, respectively.
Beyond scientific discovery, detailed seafloor maps have practical applications in various maritime activities, including safe navigation and the strategic placement of underwater communication cables. Understanding seafloor topography also enhances our knowledge of deep-sea currents and tides that impact marine life and weather patterns. The mapping techniques developed for this project could have broader applications beyond Earth, potentially aiding in the exploration of distant planetary systems and exoplanets through gravitational mapping techniques.