Why Paleontologists Are Getting Into Florida’s Oyster Business – Mother Jones

The Florida Panhandle has been an oyster paradise for many years. Apalachicola Bay—which is one of the last places in the country where oystermen are still required to use wooden tongs to harvest wild oysters, rather than dredging—has been its epicenter. These salty waters once produced 90 percent of Florida’s oysters, which were slurped up by connoisseurs throughout the Southeast. Over the past century, however, overharvesting and suffocating sediment have caused many of the panhandle’s oyster reefs to vanish. The rise in industrial waste along the coast has contributed to the coast’s decline. In 1971, the poor water quality led to an outbreak of disease that wiped out more than 90 percent of the region’s harvestable oysters. Apalachicola Bay closed its once-vibrant oyster farm in 2020. It did so for five consecutive years.

The ripple effect of the loss oysters had on the entire coast environment. Oysters are vital ecosystem engineers and top-notch water filters—a single adult oyster can filter up to 50 gallons of water in just 24 hours. Oyster reefs protect coastal areas from waves and storms. Due to their economic and ecological importance, the need to restore the area’s oyster reefs was obvious. The problem was that restoration efforts in the area hit a snag in 2018. It was because of poor environmental monitoring prior to the reefs’ collapse, no one knew what a successful restoration looked like. “The question I get asked all the time is, ‘what was this area like before?’” says Jonathan Brucker, manager of the Florida Panhandle’s aquatic preserves. “All I can say is, ‘I don’t know.’”

Paleontologists were therefore an unlikely ally for conservationists. “It’s the only way possible to answer these questions,” Dietl says.

“By digging down into the reef, we can essentially go back in time,” Dietl explains. “We’re filling in the data they never collected.” To accomplish this, Dietl and his team used sediment cores to dig through the top layer of living shells and access the compacted underworld of the area’s once-thriving oyster community. The shells age faster the deeper you dig. “The shell that was at that location in the past gets entombed in the reef framework,” says paleontologist Stephen Durham, who obtained his Ph.D. under Dietl at Cornell and now works for the DEP. “It was these historical buried shells that we were after.”

However, harvesting oysters was difficult. The oyster reefs are surrounded at low tide by viscous, sometimes thigh high mud. The shells are razor-sharp, and often covered with bacteria. This made heavy gloves and a solid balance necessary when maneuvering around the exposed coral reefs.

The gray, fossilized oyster shells, rough and often stippled with barnacles, don’t look like much, but collectively they preserve decades-worth of crucial data. The researchers were particularly interested in how oyster size had shifted over the course of the fishery’s collapse. According to Durham, the size of an oyster’s shell can tell you how fast the animal grew, how long it lived, and how it responded to changes in water quality during its lifetime, among other information.

Measuring the shell sizes of past generations and creating a timeline based on that data also helped the scientists combat the phenomenon of shifting baselines—what Dietl calls “generational amnesia.” Because environmental decline occurs over time, it can alter perception of natural conditions. Although the oysters that poke above the waves today may appear normal, researchers may discover that they are half the size and more robust than their ancestors.

After they are measured, the shells are deposited in PRI’s collection. Some 40,000 shells harvested from Florida’s oyster reefs have already made their way up to Ithaca, neatly arranged in drawers or swaddled in plastic and stored in buckets. Each shell contains important data that helps to determine the future of Florida’s oysters. All of the information is added to a database that will help environmental managers determine which reefs have declined the most—and which have the potential to be saved.