Fish in the Florida Keys swim above the coral reef, near Key Largo. | Carolyn Van Houten/The Washington Post via Getty Images

The idea of extinction — the permanent loss of life — is frightening. Yet the stakes of losing plants and animals are often unclear. If an already-rare bird vanishes from the forest, most people probably won’t feel the impact.

But a troubling situation unfolding in Florida is different. Following a record-shattering heat wave in 2023, two marine species are now nearly extinct in the state — and the impact of that loss on human life will likely be felt for generations.

In a new study published this week in Science, researchers found that elkhorn and staghorn corals — two species once fundamental to the structure of Florida’s reef — are now “functionally extinct” in the state. That means these animals are so rare that they no longer serve a function in Florida’s marine ecosystem.

Why extreme heat kills corals

Corals are colonies of living animals, known as polyps, that have a symbiotic relationship with a kind of algae that lives inside their cells. The algae give coral food — and their color — in exchange for nutrients and a place to absorb sunlight.

When the ocean gets too hot, however, this symbiotic relationship breaks down, and the polyps expel the algae and turn white. This is bleaching. When a coral is bleached, it’s essentially weak and starving, and if the heat persists, it can die.

During extreme marine heat waves — like what Florida saw in summer 2023 —........

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