Some corals look like undersea gardens, gently blowing in the breeze. Others look like alien brains. But in their skeletons are clues that promise to give scientists a detailed picture of the weather from 500 years ago. Reading these bones? Easy. As long as you have the world's most powerful X-ray laser.
DEEP LOOK: a new ultra-HD (4K) short video series created by KQED San Francisco and presented by PBS Digital Studios. See the unseen at the very edge of our visible world. Get a new perspective on our place in the universe and meet extraordinary new friends. Explore big scientific mysteries by going incredibly small.
Is coral a plant or animal?
Corals are unusual creatures. They are actually a partnership- or symbiosis- between an animal (a polyp) and a plant (algae) in which they work together to survive and thrive.
How does coral grow?
Tiny animals called polyps form an exoskeleton to live in. When one polyp dies, another builds a new home right on top of the old one. Beneath lies the abandoned exoskeletons, like an ancient city made of layer upon layer of old dwellings.
What is coral made of?
Coral exoskeletons are mostly made of calcium carbonate. But sometimes the polyps incorporate tiny amounts of other elements from the surrounding water, including the element strontium. Biologists don’t fully understand why polyps absorb strontium, but it’s a phenomenon that happens consistently across the world’s oceans.
When sea surface temperatures are warmer, corals absorb less strontium into their exoskeletons. When they are colder, they absorb more. By comparing the strontium-to-calcium ratio over time, scientists are able to reconstruct sea surface temperatures from the past. They also can chart long-term climate cycles that occurred over the lifespan of the coral. Since these corals can live for over 500 years, this gives us insights into the weather hundreds of years before written scientific records.
Read the article for this video on KQED Science:
More great Deep Look episodes:
Where Are the Ants Carrying All Those Leaves?
What Happens When You Put a Hummingbird in a Wind Tunnel?
Pygmy Seahorses: Masters of Camouflage
See also another great video from the PBS Digital Studios!
It’s Okay to Be Smart: The Oldest Living Things In The World
More KQED Science:
KQED Science: http://ww2.kqed.org/science
Funding for Deep Look is provided in part by PBS Digital Studios and the John S. and James L. Knight Foundation. Deep Look is a project of KQED Science, which is supported by HopeLab, The David B. Gold Foundation; S. D. Bechtel, Jr. Foundation; The Dirk and Charlene Kabcenell Foundation; The Vadasz Family Foundation; Smart Family Foundation and the members of KQED.