NASA's new underwater map reveals nearly 100,000 hidden mountains beneath the ocean

Scientists have come up with a new high-resolution map of the ocean floor. The newly released findings show nearly 100,000 underwater mountains that were previously unknown.

David Sandwell from Scripps Institution of Oceanography contributed to this research and credits advanced satellite observations for the detailed results.

The SWOT mission, launched in December 2022, is central to collecting the critical data that enabled this mapping effort.

How satellites outpace ships

Mapping the ocean floor with ships takes time, fuel, and money. Even with sonar, a single vessel might only cover a narrow strip of seafloor each day.

Satellites like SWOT cover about 90% of the Earth every 21 days. They don’t match the detail of sonar, but they make up for it with speed, scale, and frequency of observation.

Why seafloor maps matter

Ships equipped with sonar instruments can survey the ocean bottom directly, but only about one-quarter of the seafloor has been charted in this way. That knowledge gap spurred scientists to turn to satellite-based data for a bigger picture.

“Seafloor mapping is key in both established and emerging economic opportunities, including rare-mineral seabed mining, optimizing shipping routes, hazard detection, and seabed warfare operations,” said Nadya Vinogradova Shiffer at the end of a NASA statement.

Accurate mapping has practical uses for navigation and cable-laying, and it also shapes our understanding of ocean processes. 

Hidden ocean mountains

Seamounts are underwater mountains that rise from the ocean floor but do not break the surface. These features were once hard to detect if they measured less than about 3,300 feet in height.

The new satellite map can sense seamounts less than half that tall. By zeroing in on tiny gravitational “bumps” on the water’s surface, the data predict the position of these newly discovered peaks, boosting known seamount counts from 44,000 to nearly 100,000.

The technique behind the map depends on gravity – not cameras. Since seamounts and abyssal hills have more mass than the surrounding seafloor, they tug slightly more on the ocean above them.

That tug creates tiny rises in the water’s surface, sometimes only a few centimeters high. The SWOT satellite detects those subtle changes and translates them into detailed maps that outline what’s below.

Influence of abyssal hills

“Abyssal hills are the most abundant landform on Earth, covering about 70% of the ocean floor,” said Yao Yu at the end of a recent study. Scientists also looked at abyssal hills, which are smaller mounds covering much of the deep sea. 

These rolling ridges can be just a few miles wide, making them difficult to observe from previous satellites. Any shifts in tectonic plates over time leave patterns on these hills, creating a geological record that is now clearer than ever.

Ocean mountains, currents, and tides

Seafloor structures direct deep-sea currents that move heat and nutrients across the globe. Currents flowing over steep slopes can drive pockets of marine life to gather near the slopes, forming biodiversity hotspots.

Understanding these dynamics leads to better insights about how ocean patterns impact climate and marine ecosystems.

Oceanographers look at everything from tidal movements to nutrient exchange in these areas and plan to refine that analysis further with ongoing data collection.

Life thrives in hidden places

Underwater mountains and hills create slopes where currents slow down just enough to drop nutrients. These nutrient-rich zones become gathering spots for plankton, fish, and deep-sea corals.

Even in the darkest parts of the ocean, these formations act like magnets for life. Mapping them helps scientists locate fragile ecosystems that may need protection from deep-sea mining and trawling.

Bridging the knowledge gap

Mapping isn’t the main purpose of the SWOT satellite, but its radar altimeter collects precise measurements of water heights.

That information can be converted into a topographic map of the sea surface, which mirrors the contours of the bottom.

This helps researchers chart terrain in places where ship-based sonar data remain sparse. It also complements efforts by the Seabed 2030 project to fully survey the global seafloor by the end of this decade.

Unexpected military and climate benefits

Improved seafloor maps don’t just help scientists and sailors. Defense agencies use them to detect submarines, design sonar strategies, and assess undersea terrain for stealth operations.

The same data also play a role in climate modeling. Accurate bathymetry helps researchers trace heat flow in the ocean, a major factor in predicting long-term weather patterns and identifying areas vulnerable to sea level changes.

What’s next for these ocean mountains?

Scientists plan to measure the depth of each feature more precisely next. They have squeezed out nearly all possible details about seafloor shapes from the first year of SWOT data, which could revolutionize future marine research.

Even with the best technology, complete sonar-based coverage of Earth’s ocean will still take time. However, satellite missions like SWOT will speed up progress and ensure more sections of the ocean floor are understood.

The study is published in Science.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–