Mysterious underwater crop circle

The mysterious underwater circles discovered off the coast of Denmark are not the work of aliens or spiders. Or alien spiders, unfortunately. Rather, the rings are the result of poisonous sulfides soaked into the mud that coats the seabed, experts say.

Photos of undersea rings first surfaced in 2008. Since then, people have compared the mysterious things to crop circles or fairy rings, those lovely little mushroom designs that can sometimes sprout on your lawn. . But no one knew what the water rings were or why they were there. Some of them were nearly 50 feet across, were they WWII era bomb craters?

In 2011, scientists determined that the rings themselves were made of seagrass, a native type of seagrass that is home to small fish and other crustaceans.

Late last year, after studying the circles, the same team discovered that an interaction between seagrass and seabed sulphides sculpt mysterious shapes.

Normally, eel stands grow outward in a radial pattern, forming large circular mats of grass. But as the grasses grow and populate the shallows, they tend to grab and sequester the mud that would normally continue to move along the seafloor. As the sulfur-saturated mud accumulates around the seagrass, the poison begins to kill the plants, starting with the oldest, weakest weeds in the center of the circle.

Reports: wired