A team of experts from the Scripps Institution of Oceanography, the University of California, San Diego (United States), Chungnam National University (Republic of Korea) and the University of Hawaii (USA), have mapped 19,000 previously unknown seamounts and volcanoes in the world's oceans using data from radar satellites.
In their paper published in the journal Earth and Space Science, the group describes how this new seafloor-observing technology is used to find and map relatively small submarine volcanoes and explains why understanding the morphology and evolution of these geological formations is important.
The ocean floor, like dry land masses, features a wide variety of terrain. And just like with the mainland, the features that really stand out are the mountains; in the ocean they are called seamounts. And just like on Earth, they can be created by tectonic plates pushing against each other, or by erupting or dormant volcanoes.
Currently, only a quarter of the sea floor has been mapped in detail, meaning no one knows how many seamounts exist or where they might be. This can be a problem for submarines. In the last decade, at least two US submarines are known to have collided with seamounts, putting the vehicles and their crews at risk. But not knowing where the seamounts are presents another problem. Prevents oceanographers from creating models that represent the flow of ocean water around the world.
In this new effort, the research team set out to discover and map as many seamounts as possible, using data from satellites with radar equipment to do so. Such satellites cannot actually see seamounts, but instead measure the altitude of the sea surface, which differs due to changes in the gravitational pull related to the topography of the seabed; an effect known as sea mounding. In doing so, they found 19,000 previously unknown seamounts, many of them caused by volcanoes.
In their paper, the team notes that other important reasons to map the ocean floor include things like helping with seafloor mining efforts: Seamounts are home to vast amounts of rare-earth minerals. More comprehensive seamount maps would also help geologists better map plate tectonics and the planet's geomagnetic field. In addition, some seamounts provide a habitat for a wide variety of marine life.
One notable aspect is that seamounts have a very strong impact on deep-water ocean flow. As currents rush toward these elevations they are pushed toward the surface, carrying cooler water with them and mixing in unknown ways. Mapping such currents is more important as the oceans absorb more heat and carbon dioxide from the atmosphere, and fresh water melts, due to ongoing climate change.
