The barnacle Chthamalus bisinuatus is the only sessile invertebrate colonizing oil patches on beachrocks one year after a massive oil spill on the Northeastern Brazilian coast.

A large-scale oil spill has reached over 3000 km of the NE Brazilian coast since August 2019. The cause and origin of this spill remain mysterious, and the impacts on coastal ecosystems have not been clearly understood so far. Despite the efforts to remove the oil (mainly from local communities), oil stains are still present in beaches, mangroves, and beachrocks.