A major scientific breakthrough in ocean floor mapping has been achieved with new data from NASA’s Surface Water and Ocean Topography (SWOT) satellite, which revealed approximately 100,000 seamounts across the globe—more than doubling previous estimates. This achievement marks a significant advancement in the ability to chart underwater topography, an area covering over 70% of Earth’s surface. Researchers have long struggled to create detailed maps of the ocean floor, but the precision offered by SWOT represents a pivotal shift in marine exploration.
David Sandwell, a geophysicist at Scripps Institution of Oceanography, highlights that SWOT’s capabilities are a monumental leap forward in ocean floor mapping. Published in Science in December 2024, the findings demonstrate how the satellite’s ability to detect minute centimeter-scale differences in sea surface height—caused by gravitational pulls from underwater features like seamounts—allows scientists to identify even smaller seafloor formations. Previous satellites could only detect seamounts taller than one kilometer; SWOT now detects those half that size, drastically expanding our underwater vision.
The new maps reveal a rich variety of geological formations: towering seamounts, abyssal hills arranged like washboard ridges, deep ocean trenches, continental margins, and tectonic fracture zones. Yao Yu, lead author of the study, notes that abyssal hills—parallel bands formed as tectonic plates move apart—are the most abundant landform on Earth, covering roughly 70% of the seafloor. These features are now visible thanks to sophisticated color-coded mapping, where reduced gravity areas appear purple and elevated structures green, enhancing scientists’ interpretation of complex underwater landscapes.
Despite the high precision of sonar mapping from ships, only about 25% of the ocean floor has been surveyed that way. The SWOT satellite’s broad coverage helps bridge critical gaps, providing unprecedented insights into geological processes that shape Earth’s surface over millions of years. Through ocean floor mapping, scientists can reconstruct ancient tectonic movements and better understand planetary evolution.
Seamounts, in particular, have profound ecological significance. Acting as underwater oases, they influence deep-sea circulation patterns, concentrate nutrients, and harbor diverse marine ecosystems. The discovery of tens of thousands of previously uncharted seamounts suggests that many more biodiversity hotspots exist, potentially supporting unique life forms adapted to extreme environments. Recent findings even show living microbes thriving in ancient rock formations, hinting at untapped biological mysteries beneath the waves.
Beyond ecological value, detailed seafloor maps are essential for practical purposes such as safer maritime navigation and the strategic placement of underwater communication cables—the backbone of the global internet. Understanding how underwater landscapes interact with ocean currents also informs weather modeling, an increasingly important area as climate change accelerates.
The gravitational mapping techniques demonstrated by SWOT exemplify the powerful fusion of space technology and marine science. These methods may one day be adapted to explore extraterrestrial oceans, like those suspected beneath Jupiter’s moon Europa. Just as SWOT advances ocean floor mapping on Earth, similar techniques could help detect hidden features on distant worlds.
Ultimately, this landmark achievement in ocean floor mapping reveals a hidden but vital world that shapes marine biodiversity, global climate systems, and our broader understanding of Earth’s dynamic history. As technology progresses, humanity’s grasp of the deep ocean—our planet’s final frontier—will only deepen and expand.
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