It’s 4 a.m. and the alarm rings out in the dark of our little boat cabin. We are anchored along the coast of Grand Turk, and the sky is still a canopy of stars. My husband Alexis and I fumble through the sailing morning ritual -coffee, life jackets, and raising the sails. And by the time the anchor’s up, we’re slicing into the pre-dawn sea, riding the wind toward our next stop: Providenciales.

From the outside, “Provo” is a Caribbean postcard. White sand beaches, turquoise shallows, calm coves. But beneath that surface lies a reef system in crisis.

Turks and Caicos, like much of the Caribbean, is facing an ecological emergency. Climate change has long posed a threat to coral reefs. But now, a fast-spreading and lethal disease is devastating them at an unprecedented pace. It’s called Stony Coral Tissue Loss Disease, or SCTLD. And in the span of just a few years, it’s changed everything.

When we arrive in Provo, I meet with Alizee Zimmermann, Executive Director of the Turks and Caicos Reef Fund. Her team has invited me to their underwater coral nursery, where coral fragments are grown and tended before hopefully being reintroduced back onto reefs.

The morning is hot. We bounce in a beat-up truck down dusty roads toward the coast, where their dive boat waits to ferry us, along with a handful of volunteers, to the south of the island. As we load tanks, fins, and crates of gear onto the deck, the heat shimmers off the horizon. It’s hard to imagine looking around at the glittering ocean, that beneath it, a crisis is unfolding.

Twenty minutes later, we’re floating above the nursery. Kitted up in scuba gear, I plunge into the crystal clear water and descend slowly, watching the coral trees below rising out of the seafloor. Built from PVC piping, they stand tall like trees in an underwater orchard, each one hung with strands of growing coral. It’s otherworldly and peaceful. But it takes a lot of hard work to maintain it.