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Aaron O’Dea’s time machine is a 20-foot aluminum tube. Beneath the waters of Panama’s western Caribbean,
he drives it into the rubbly seabed with a 45-pound cylindrical hammer. The strenuous effort quickly depletes oxygen tanks and leaves Aaron
and his team aching and breathless.

Although the dive site seems pristine, the scenery is deceiving. Surrounded by warm, emerald waters and untouched mangrove islets, Panama’s Bocas del Toro -like most coasts of the Caribbean- abounds in natural beauty. But beneath the surface, the seabed once blanketed in vibrant reef communities is now covered with grayish dead coral.

Like a detective on a cold case, Aaron O’Dea, a paleobiologist at the Smithsonian Tropical Research Institute (STRI) and collaborators Katie Cramer (Smithsonian MarineGEO post-doc) and Richard Norris (Scripps Institution of Oceanography), drill down hundreds of years into the seabed in search of clues to present day changes in marine ecosystems of the Caribbean.

Coral fossils are emissaries of the ocean’s past. Highly sensitive to environmental changes, they serve as indicators of ocean health. Though warming seas, acidification, pollution and overfishing are generally held responsible for the decline of coral reef communities, precisely when and why their deterioration began is unknown.

“The health of the oceans is like a patient with a complex medical history who falls ill in a foreign country. If local doctors treating the patient don’t have a full medical history, they may endanger the patient’s life,” says O’Dea who sees how baseline data will aid marine conservation efforts. “If we wish to diagnose and treat life in the seas, it is essential we know the ocean’s history.”

With each hammer strike, the coring system delves into the past collecting sediments and fossils. Aaron and collaborators journey 50 years back in time just prior to the precipitous decline of the reefs. One hundred years ago reveals the impact of Bocas del Toro’s first intensive banana plantations. Five hundred years into the past corresponds to the arrival of Europeans to this 9,000 year-old archipelago that is now an international tourist destination.

“The question is, what did the Caribbean look like in the past and what were the principal drivers of the changes we see today,” says O’Dea. The fossils will tell the story.

Core samples with marine sediments layered one on top of the other will be sent to Scripps Institution of Oceanography where state-of-the-art scans will determine the types of sediment retrieved. Shellfish fossils will be dated with uranium-thorium, revealing their dates to within a handful of years. Back in Panama and California, the team of lab assistants and students will spend months interpreting the fossilized mollusks, coral, clams and more; cleaning and classifying them according to age to reconstruct the marine history of Bocas del Toro.

“Once we demonstrate our aim in Bocas del Toro, we’ll expand both spatially and temporally throughout the Caribbean and the rest of the world. Our findings will be used to direct the recovery of the seas.”

The team’s coring system consists of a 6-meter (20-foot) aluminum tube marked off into 20-centimeter (8-inch) sections. These visual references help his team monitor how far the cylinder has entered the seabed.