Continued efforts to learn more about the submerged worlds hidden under Earth's oceans have been rewarded with the discovery of thousands of previously uncharted seamounts.
A team led by David Sandwell and Brook Tozer at the Scripps Institution of Oceanography in San Diego, California, uncovered the new undersea mountains –– estimated to range in number from 5,000 to 10,000 –– thanks to advancements in satellite technology, according to New Scientist. The team's findings, valuable for applications like undersea navigation, climate modeling and tsunami prediction, have been added as an update to SRTM15+V2.0, the world's most detailed map of the ocean floor.
"Despite the importance of Earth's ocean floor to our quality of life, we have made much better maps of the surfaces of other planets, moons, and asteroids," writes Sandwell in Bathymetry in Space, a 2002 report summarizing the need for better a topographic understanding of the ocean floor.
What lies beneath
Seamounts, typically formed by extinct volcanoes and rising anywhere from 3,000 feet to over 13,000 feet, are estimated to number at least 100,000 throughout the Earth's oceans. Of the 350 or so that have been sampled, they've also been found to host extremely rich ecosystems for a wide array of marine species. As a result, scientists are eager to document as many as possible in an effort to protect these biodiversity hotspots from destructive fishing and deep sea mining practices.
"If you think of it, the deep sea is where most of the living space on this planet actually is," Dr. Carl Gustaf Lundin of the International Union for Conservation of Nature told ABC. "And you are dealing with large machines that could really turn up a lot of the sea bottom and cause significant changes to some of the key habitats down there."
With ship-based sonar having only mapped between 10-15 percent of the sea floor, the real breakthroughs for seamount discovery have come via satellites equipped with altimeters. Because seamounts exert a gravitational pull on the water above and around them, altimeters are able to pick them up via small "bumps" in sea levels on the ocean's surface. With each new generation of satellite technology, researchers have been able to take advantage of ever-increasing sensitivity to detect these subtle surface features.
"In 2014, we could map all the seamounts more than about 2 kilometer tall, today we can detect any taller than about 1.5 kilometer," Sandwell told New Scientist.
Dive every mountain
A map of a seamount in the Arctic Ocean created by NOAA's Office of Coast Survey by gathering data with a multibeam echo sounder. (Photo: NOAA/Flickr)
Researchers are looking ahead to 2021, when NASA's SWOT satellite (Surface Water and Ocean Topography) is expected to launch aboard a SpaceX Falcon 9. Developed by an international group of hydrologists and oceanographers, the satellite will create the first global survey of the Earth's surface water, with seamount detection as sensitive as 1 kilometer (3,200 feet) high.
Together with the United Nations-backed Project Seabed 2030, a $3 billion effort to map the entire sea floor, it's hoped that whatever mysteries we uncover will help inform future conservation policies.
"People keep saying we don't want to touch the ocean, it's too pristine, it's too rich, but we don't even know what to conserve," Geoffroy Lamarche, a team member of the project, told ABC. "We need to know what's there, to know how to conserve it for future generations."