From storing carbon to guarding against ocean acidification, seagrass is fundamental to keeping ocean ecosystems in balance. But new research shows that seagrass meadows play another crucial, if overlooked, role: protecting shipwrecks and other underwater historical heritage. Ancient weapons, prehistoric fishing tools, and textiles are just some of the items scientists have discovered buried beneath the protective cover of seagrass, says Oscar Serrano, a marine ecologist at Edith Cowan University in Australia. Until now, Serrano says, no one has investigated the cultural value of seagrass meadows, which “play an important role in revealing clues about the human past.”

For thousands of years, seafood has sustained communities, livelihoods, and economies across the world. In ancient Rome, wealthy entrepreneurs snapped up beachfront property and built elaborate fish farms. In 15th-century Chile, coastal people bartered shellfish for inland resources. The Vikings living on Norway’s Lofoten Islands were fierce and powerful raiders, but they were also prodigious fishers of Atlantic cod. Over millennia, shifts in politics and changing technology have drastically altered when and where people go to fish. But accurate scientific records of this vast history of fishing activity capture, at best, a tiny sliver of the whole.

Vibrant images of coral reefs are popular features in glossy travel magazines. This spiraling kaleidoscope of neon corals leads many to believe that “pretty” must also mean “healthy.” But according to Julie Vercelloni, a marine scientist at the University of Queensland in Australia, something more sinister is often at play when corals turn a fluorescent shade.