Trouble at the reef: The twenty-first century's medicine cabinet

Trouble at the reef: The twenty-first century’s medicine cabinet

It is this layer that forms the basic structure of the ufabet reef, and without these little chaps there would be nowhere for its myriad creatures to live.

Trouble at the reef: The twenty-first century’s medicine cabinet

Trouble at the reef: The twenty-first century's medicine cabinet

Corals depend on sunlight and clear, warm seas. The polyps need sunlight because they are packed with single-celled, symbiotic dinoflagellates, called zooxanthellae, which live in their tissues. They manufacture food by photosynthesis, and the coral polyps obtain up to 90 per cent of their energy from them.

The remaining nutrients come from food particles trapped by the polyp’s tentacles. Without their tiny lodgers the polyps would be unable to grow fast enough to build and maintain the massive reef structures we see today, yet the polyp-zooxanthellae relationship is a fragile co-existence.

If polyps are stressed by change for sustained periods, such as significantly warmer or colder water, pollution, or smothering by sediment from rivers, they expel their zooxanthellae, a process known as ‘bleaching’. The corals literally turn white, since the sunlight-harvesting pigments in the zooxanthellae give corals their colour.

The corals are not necessarily dead and can survive short periods of elevated temperatures however, if temperatures remain high for extended periods of time they will bleach permanently and die. Corals often live just below levels that can cause thermal ยูฟ่าเบท stress and are therefore highly vulnerable to climate change and coral bleaching.

Australia’s Great Barrier Reef is currently reeling from the worst bleaching event in its history, according to the Great Barrier Reef Marine Park Authority. In the northern part of the reef, 95 per cent of corals have been damaged, including the home of Percy the tuskfish.

Even so, for all their fragility, corals are enormously resilient and can bounce back from, say, a single major change. Nowadays, though, they are being hit by more frequent changes in the environment – one day heatwaves and cyclones, the next day an outbreak of voracious crown-ofthorns starfish: it’s death by a thousand cuts. And coral reefs, as we have learned, are the ocean’s pharmacopoeia.

If we lose them, the twenty-first century’s medicine cabinet starts to look bare.