If you've been to Hilton Head Island's beach this week, you may have seen — and smelled — an unfamiliar type of seaweed that's been washing up in recent days.
It's green when it floats ashore, and as it dries out, it turns brown and gives off a fishy smell, but — after a recent shark attack and the appearance of stinging Portuguese man-of-wars over the Memorial Day weekend — you may be relieved to find that this seaweed, called sargassum, is a harmless algae.
Carlos Chacon, manager of natural history with the Coastal Discovery Museum at Honey Horn, said on Wednesday that sargassum comes from far out in the open Atlantic. And — though is is unsightly and smelly — it does not sting or bite.
He said it originates in an area of the ocean known as the Sargasso Sea, where it floats far offshore in huge mats that are usually kept in place by the currents that surround it.
At sea, sargassum is an important habitat for loggerhead sea turtle hatchlings and American eels, as well as other sea creatures, he said.
Occasionally though, wind and currents will cause pieces of it to break off and quantities will drift ashore. "It happens every now and then," he said.
"It's not dangerous. There's no detriment aside from the way it looks — it looks kind of trashy."
He said the algae will will quickly deteriorate in warm weather and full sun, but as it does so, it will give off a pungent smell. If no more washes up, it should be gone in a week or two.
The only question is how much of it there will be. So far this year, only a small amount has wound up on the beach, but if conditions are right, there can be a lot. In 2012, a large raft of it washed ashore and caused a brief sensation as it piled up along the high tide line before eventually decomposing.