Gulf Oil Spill Pictures: Oiled Beaches Time Line

July: Heavy Impact

Photograph by Chris Combs, National Geographic

Tar balls and liquid oil from the Gulf spill taint Florida's Pensacola Beach on July 1. (See related pictures: "Gulf Oil Coats Popular Florida Beach.")

By February, most of the visible oil was gone from the famous white strand.

Three factors converged to speed up the oil breakdown: Responsive bacteria, calm weather, and aggressive efforts by cleanup crews organized byDeepwater Horizon Unified Command, the joint federal-industry task force that responded to the Gulf oil spill, experts say.

(See "Gulf Oil Spill Surprise: Methane Almost Gone.")

Published April 19, 2011

July: Glowing Oil

Photograph by Chris Combs, National Geographic

Under UV light, tar from the oil spill lights up orange-yellow on the beaches of Gulf Islands National Seashore, Florida (picture), while clean sand glows purple in a long-exposure picture taken in July.

Scientists who are continuing to monitor Florida's and Alabama's beaches still see traces of the oil via UV light.

(See "3 Future Oil-Spill Fighters: Sponges, Superbugs, and Herders.")

Published April 19, 2011

November: Aggressive Cleanup

Photograph by Dave Martin

Machines excavate oiled sand in Orange Beach, Alabama, on November 9.

In late July and August, raking machines that were supposed to collect oil instead pulverized many of the thick oil sheets into fingertip-size oil pieces that still dotted the beaches, Wang said.

So, over the fall and winter, crews switched to more extreme measures, deploying excavation machines that removed entire sections of sand up to 2 feet (0.6 meter) deep.

The workers then passed that sand through a sieve, catching most of the oil and leaving only fine particles, USF's Wang explained.

Sifting sand in this way gave bacteria a boost, both by breaking it into tinier pieces and making the oil more accessible overall.

(Read more about how nature is fighting the oil spill.)

Published April 19, 2011

March: Ready for Spring Break

Photograph by Eric Thayer

A surfer walks a Pensacola, Florida, beach in March.

By February, most of the visible oil had vanished, leaving them ready for spring break tourists, according to USF's Wang. (See more beach pictures.)

Yet outside Florida, there are few scientists studying oiled Gulf beaches—leaving a lot of shores unsurveyed, FSU's Huettel cautioned.

"Most of the oil layers in the tourist areas are gone, [but it's a] different story in salt marshes and remote islands," he said.

"In these areas, you can anticipate oil layers sit there for a while because you don't have cleanup efforts," he said.

(See "Why the Gulf Oil Spill Isn't Going Away [September].")

Published April 19, 2011

April: Tiny Tar Balls

Photograph courtesy Rip Kirby

Small black tar balls are barely visible amid shells in this closeup of beach sand in Pensacola, Florida, in April.

Though most of the beach oil has degraded, no one knows whether the oil sparked any lasting harm to the environment—or if trace amounts still floating in the ocean are detrimental.

For instance, microbial ecologist Dick Snyder and colleagues have discovered small amounts of polycyclic aromatic hydrocarbons (PAHs)—a toxic ingredient of oil—in water, sand, and beach clams called coquinas.

"It's those low levels of PAHs that are the concern now," said Snyder, of the University of West Florida (UWF) in Pensacola.

That's because, if the coquinas are picking up the pollutant in their bodies, there's a good chance it's found its way into other marine species up the food chain, Snyder said.

Published April 19, 2011

April: Tar Balls Aglow

Photograph courtesy Rip Kirby

Looking like gold nuggets, tiny tar balls gleam orange in UV light on a beach in Pensacola, Florida, in April.

Overall, at least for the Florida Panhandle, the environmental prognosis doesn't seem as dire as it was last summer, UWF's Snyder emphasized.

"Everyone's relieved that we don't have this huge lingering mess on our hands."

Published April 19, 2011