Tropical Storm Lee showed oil left over from last year’s BP spill isn’t breaking down as quickly as some scientists thought it would.
The latest wave of gooey tar balls that washed ashore during the storm appeared relatively fresh, smelled strongly and hardly changed chemically from the weathered oil that collected on Gulf beaches during the spill, said researchers from Auburn University.
Mats of oil — not weathered tar, which is harder and contains fewer hydrocarbons —still remain submerged on the seabed and could pose a long-term risk to coastal ecosystems, the researchers said.
BP added cleanup crews and extended their hours after large patches of tar balls polluted the white sand at Gulf Shores and Orange Beach starting Sept. 6. Tar balls also washed ashore in Pensacola, Fla., which is to the east and was farther from the storm’s path.
Marine scientist George Crozier said the findings make sense because submerged oil degrades slowly due to the relatively low amount of oxygen in the Gulf’s sandy bottom.
“It weathered to some extent after it moved from southern Louisiana to Alabama … but not much has happened to it since then,” said Crozier, longtime director of the state sea laboratory at Dauphin Island.
Crozier said remnants of the spill are “economically toxic” for tourism, but he doubts there is much of an environmental threat. The oil lingering on the seabed is of a consistency and chemical composition somewhere between crude oil and tar, he said.