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 — corals can die in a matter of days, sometimes without bleaching. Heat shock kills the polyps and causes their soft tissue to slough off their skeleton.

Starting in July 2023, water temperatures in Southeast Florida, home to........

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