Strange seagrass circles in Croatia leave experts stumped
Thursday, May 15, 2014, 5:04 - Aerial photos along the coastline of Croatia show several sand circles in a bed of posidonia oceanica seagrass and experts aren't sure why, Mashable.com reports.
Biologist Mosor Prvan told Mashable there the circles are about each 50 metres in length and roughly 300 metres away from each other.
They were first discovered in 2013 via aerial photos, but experts aren't sure what is causing them.
"At first we thought it was some sort of photo manipulation, so we dived at one of the locations, and sure enough, the circles were there. They had a perfect edge, as if someone pulled the posidonia out with a corkscrew," he told Mashable.
This isn't the first time strange circles have been discovered under the sea.
Earlier this year, experts determined that a series of strange rings in Denmark waters were the result of a poison that was killing off sections of seagrass, but the Croatian markings have different characteristics.
For example, they're larger and appear to be more uniform in shape.
Prior to that a series of 'mystery circles' captivated divers off the southern coast of Japan starting in 1995.
The mystery was solved in 2011 when the culprit was caught in the act: It was a male pufferfish that was in search of love.
The species creates incredible, intricate designs on the sea floor in order to attract a mate.