September 22, 2023

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Science is worth exploring

Satellite details reveal nearly 20,000 previously unknown deep-sea mountains

The quantity of recognised mountains in Earth’s oceans has approximately doubled. International satellite observations have unveiled approximately 20,000 previously not known seamounts, researchers report in the April Earth and House Science.

Just as mountains tower in excess of Earth’s floor, seamounts also increase higher than the ocean ground. The tallest mountain on Earth, as calculated from base to peak, is Mauna Kea, which is portion of the Hawaiian-Emperor Seamount Chain.

These underwater edifices are often scorching spots of marine biodiversity (SN: 10/7/16). That is in part due to the fact their craggy partitions — shaped from volcanic activity — provide a plethora of habitats. Seamounts also boost upwelling of nutrient-wealthy h2o, which distributes useful compounds like nitrates and phosphates during the drinking water column. They are like “stirring rods in the ocean,” claims David Sandwell, a geophysicist at the Scripps Establishment of Oceanography at the University of California, San Diego.

Additional than 24,600 seamounts have been previously mapped. Just one prevalent way of getting these hidden mountains is to ping the seafloor with sonar (SN: 4/16/21). But that is an highly-priced, time-intense system that requires a ship. Only about 20 p.c of the ocean has been mapped that way, claims Scripps earth scientist Julie Gevorgian. “There are a lot of gaps.”

So Gevorgian, Sandwell and their colleagues turned to satellite observations, which provide world wide coverage of the world’s oceans, to choose a census of seamounts.

The workforce pored above satellite measurements of the height of the sea surface area. The scientists appeared for centimeter-scale bumps induced by the gravitational influence of a seamount. For the reason that rock is denser than h2o, the existence of a seamount marginally variations the Earth’s gravitational industry at that spot. “There’s an additional gravitational attraction,” Sandwell suggests, that results in water to pile up above the seamount.

Employing that system, the team noticed 19,325 earlier not known seamounts. The scientists as opposed some of their observations with sonar maps of the seafloor to confirm that the recently found seamounts were likely true. Most of the freshly found underwater mountains are on the modest facet — involving around 700 and 2,500 meters tall, the researchers estimate.

Nevertheless, it is doable that some could pose a danger to mariners. “There’s a point when they’re shallow sufficient that they are in the depth variety of submarines,” claims David Clague, a maritime geologist at the Monterey Bay Aquarium Exploration Institute in Moss Landing, Calif., who was not involved in the study. In 2021, the USS Connecticut, a nuclear submarine, ran into an uncharted seamount in the South China Sea. The vessel is nonetheless undergoing repairs at a shipyard in Washington condition.