Highlighting the Unusual Activity of Coralliths
MES/CEE Professor Mark Patterson published a paper in Bulletin of Marine Science that reveals activity of corallith, an unusual free-living coral found of the Florida coast that thrives from the energy of storms. In his paper, “Giant Mobile Coralliths From the Florida Keys, USA,” Patterson says the exceptionally large colonies of this coral identified may be the largest and oldest spherical coralliths described to date.
This article originally appeared on Northeastern Global News. It was published by Cynthia McCormick Hibbert. Main photo: Mark Patterson, a professor at Northeastern University’s Marine Science Center, studied hundreds of coralliths off the coast of the Florida Keys. Imagery provided by Velvetfish via Getty Images
They’re living boulders on the ocean floor. Northeastern research explains the mysterious corallith
Waves generated by increasingly strong hurricanes and tropical storms have laid waste to endangered coral reefs by smashing coral branches and overturning colonies.
But an oddball type of free-living coral actually thrives on the energy created by storms.
Called a corallith, it is known as the rolling stone of the shallow ocean floor. Coralliths occur when the tumbling motion of wave energy shapes coral into spheres that can grow to be nearly 1.4 meters in diameter, at least in the Florida underwater living boulder field studied by Mark Patterson, a professor at Northeastern’s Marine Science Center.
“That’s ginormous,” Patterson says. Imagine a sphere of coral twice the width of an inflated exercise ball, weighing a couple tons and existing for 100-120 years.
Hundreds of these coralliths — large and small — are living on the sandy seabed off Plantation Key in Islamorada, Florida.
Patterson says they are the oldest and largest coral formations of this type ever discovered.
Don’t expect to find coralliths rolling around like tumbleweeds.
An expert in coral and microfluidics, Patterson calculated in a paper published in the Bulletin of Marine Science that “once every seven years was how frequently you had to have a big storm to roll the big ones.”
“When they get rolled, it’s just enough to turn over. And then enough sand gets jammed in, to stop the rolling. It’s not like they’re going back and forth” all the time, he says.
As a scientist who has studied the devastating impact of climate change on coral reefs, Patterson finds the formation of coralliths an amazing adaptation to tempestuous conditions.
“There have always been waves on this planet,” he says. “This is probably a really ancient way of coping with what storms do to animals in shallow water.”
“They have to take what Mother Nature dishes out. They don’t always get killed—they can adapt and do this marvelous thing of turning into a living sphere.”
What we think of as a hard coral reef or corallith is formed when tiny, cup-shape polyps secrete a skeleton of calcium carbonate. The layers and layers in big reefs can be seen from space.
In the case of coralliths, the polyps that are sitting on the sand probably retract and die, Patterson says.
When a storm comes along, it kicks the colony over and the colony extends its tissue to the dead areas, Patterson says.
Read full story at Northeastern Global News