The variety of recognized mountains in Earth’s oceans has roughly doubled. International satellite tv for pc observations have revealed almost 20,000 beforehand unknown seamounts, researchers report within the April Earth and House Science.
Simply as mountains tower over Earth’s floor, seamounts additionally rise above the ocean ground. The tallest mountain on Earth, as measured from base to peak, is Mauna Kea, which is a part of the Hawaiian-Emperor Seamount Chain.
These underwater edifices are sometimes scorching spots of marine biodiversity (SN: 10/7/16). That’s partly as a result of their craggy partitions — fashioned from volcanic exercise — present a plethora of habitats. Seamounts additionally promote upwelling of nutrient-rich water, which distributes helpful compounds like nitrates and phosphates all through the water column. They’re like “stirring rods within the ocean,” says David Sandwell, a geophysicist on the Scripps Establishment of Oceanography on the College of California, San Diego.
Greater than 24,600 seamounts have been beforehand mapped. One frequent method of discovering these hidden mountains is to ping the seafloor with sonar (SN: 4/16/21). However that’s an costly, time-intensive course of that requires a ship. Solely about 20 p.c of the ocean has been mapped that method, says Scripps earth scientist Julie Gevorgian. “There are a variety of gaps.”
So Gevorgian, Sandwell and their colleagues turned to satellite tv for pc observations, which offer international protection of the world’s oceans, to take a census of seamounts.
The group pored over satellite tv for pc measurements of the peak of the ocean floor. The researchers seemed for centimeter-scale bumps attributable to the gravitational affect of a seamount. As a result of rock is denser than water, the presence of a seamount barely adjustments the Earth’s gravitational discipline at that spot. “There’s an additional gravitational attraction,” Sandwell says, that causes water to pile up above the seamount.
Utilizing that method, the group noticed 19,325 beforehand unknown seamounts. The researchers in contrast a few of their observations with sonar maps of the seafloor to substantiate that the newly found seamounts had been seemingly actual. Many of the newly found underwater mountains are on the small facet — between roughly 700 and a pair of,500 meters tall, the researchers estimate.
Nonetheless, it’s attainable that some may pose a danger to mariners. “There’s some extent after they’re shallow sufficient that they’re throughout the depth vary of submarines,” says David Clague, a marine geologist on the Monterey Bay Aquarium Analysis Institute in Moss Touchdown, Calif., who was not concerned within the analysis. In 2021, the USS Connecticut, a nuclear submarine, bumped into an uncharted seamount within the South China Sea. The vessel continues to be present process repairs at a shipyard in Washington state.