The blob (Chukchi Sea algae)
The blob was the name given to a large black algal bloom that was first spotted floating in the Chukchi Sea between the Alaskan cities of Wainwright and Utqiaġvik in July 2009. == Discovery and location == The mass was initially discovered by a civilian boat from Wainwright and reported to the U.S. Coast Guard due to concerns that it could have been an oil spill.
Source: Wikipedia — The blob (Chukchi Sea algae) (CC BY-SA 4.0)