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apply. This is Scientific American 60 Second Science.

I'm Annie Sneed.

Coral reefs are among the most productive ecosystems in the world.

They're also in serious danger. Climate change and other threats are killing them off.

But researchers have come up with an invention they think could help the reefs.

3D printed corals. At the heart of reef ecosystems lies a symbiosis between corals and algae.

Colds use light. They're photosynthesizing, so they have microscopic algae inside the tissues.

And these use light to generate energy and that energy is then transferred to the

call animal host and that the animal host in return transfer certain byproducts to the algae and so they have a symbiosis going on.

Daniel Weng Percert, a coral reef scientist at the University of Cambridge.

This tight-knit bond between algae and corals is what makes reef so incredibly productive.

And because of this symbiosis corals have involved sophisticated skeletal and

tissue structures for collecting sunlight.

So usually you would have this kind of rapid light attenuation, but through the skeleton, a light is kind of pumped and guided into deeper otherwise shaded areas.

...