Scientists plant heat-resistant hybrid corals to revive Florida's dying reefs

Scientists have taken a bold step to revive Florida’s devastated elkhorn coral populations. This spring, nearly three dozen lab-grown corals—including a new cross-bred variety—were planted in Dry Tortugas National Park. The move follows the near-total loss of these vital reef-builders after a record-breaking marine heatwave in 2023. Elkhorn corals once thrived across Florida and the Caribbean, forming the backbone of reef ecosystems. But in 2023, extreme ocean temperatures triggered a catastrophic bleaching event, wiping out almost every colony in the region. By the end of that year, researchers declared the species functionally extinct in the Florida Keys and Dry Tortugas.

In response, Andrew Baker, a marine biologist at the University of Miami, searched for solutions beyond Florida’s waters. His team turned to elkhorn colonies in Tela Bay, Honduras, known for their resilience to heat stress. In early 2024, they collected and transported these hardier corals to Florida for cross-breeding experiments.

The effort produced the first generation of hybrid corals, nicknamed 'Flondurans'—a blend of Florida and Honduran genetic lines. These lab-raised corals were nurtured in tanks before being carefully moved to the ocean. Bailey Marquardt, a doctoral student at the university, oversaw their outplanting in April, marking the first time the new hybrids were introduced to the wild.

The project aims to test whether these cross-bred corals can better withstand rising sea temperatures. If successful, they could help restore Florida’s reefs, which provide essential habitat for marine life and protect coastlines from erosion. The newly planted corals now face their first real test in the open ocean. Their survival could determine whether cross-breeding offers a lifeline for Florida’s struggling reefs. For now, scientists will monitor their progress closely in the months ahead.