For the first time, the phenomenon of a double whirlpool has been observed. The discovery was made by a team of scientists at the University of Liverpool, and serves as a confirmation of an occurrence that was only theoretically possible for decades.
The Double Whirlpool
Large whirlpools in the open ocean are known as eddies, and these huge spiraling pools can span hundreds of miles. Two connected eddies spinning in opposite directions was considered a possibility, but hadn’t been observed until now. Chris Hughes, a University of Liverpool oceanographer, was lead author of the study.
“Ocean eddies almost always head to the west, but by pairing up they can move to the east and travel ten times as fast as a normal eddy, so they carry water in unusual directions across the ocean.”
A double whirlpool is known as a modon, and has been theorized to exist for decades at this point. While we had never seen one in the wild, Hughes and the team received solid evidence of a double whirlpool while studying satellite footage of the ocean surrounding Australia. In an interview with Popular Science, Hughes elaborated on his find.
“I happened to notice one little feature down in the Tasman Sea that was behaving very strangely compared to everywhere else…Almost all these eddies drift slowly westwards, but this little feature was going quickly eastwards.”
It turns out that modons are not actually as rare as scientists originally thought. Apparently, there have been multiple instances of a double whirlpool captured on satellite imagery for quite some time – scientists were just looking in the wrong place.
Double Whirlpool Mechanics and Significance
There’s still a significant amount of research that needs to be done to determine conclusively what exactly causes a double whirlpool, but scientists have arrived at a theory that could potentially explain the occurrence.
The current idea is that a double whirlpool forms when two whirlpools collide together in the ocean. It’s also possible that the whirlpools form from friction impacting eddies close to the coast. Once a whirlpool is formed, a modon makes an underwater vortex and can last for up to six months.
While the formation of a double whirlpool is a cool find in and of itself, it turns out that these modons could play a significant role in the ocean ecosystem. Hughes shared his thoughts with Popular Science:
“My thinking is that these linked, fast-moving eddies could ‘suck-up’ small marine creatures and carry them at high speed and for long distances across the ocean…You would get particular blobs of water where the biology and the conditions are totally different from the surrounding area. It’s quite possible there are shoals of particular types of fish following these eddies for their special conditions. Fish would actually actively follow the eddies by choice because of what’s in them.”
There’s no doubt that more research is needed to determine how exactly a double whirlpool forms as well as the exact implications of such a phenomenon, but this confirmation of a theory that has been held for decades is an exciting breakthrough for oceanographers.
For more information, you can take a look at the study in Geophysical Research Letters.