As things heat up here on Earth, our oceans are warming faster than anything else, and our reefs just can’t take it anymore.

Clearly, that’s bad news for reefs. But it’s also bad news for all of us.

Because reefs are like the rainforests of the ocean, and if they die, they take enormous ecosystems down with them. So scientists have started looking into some pretty off-the-hook ideas that just might help save coral reefs. Including 3-D printing them from scratch. [intro jingle]

Corals are especially sensitive to climate change because of where they live: in tropical waters that get lots of sun.

They need all that sun because they get their energy from algae that live inside their cells, and those algae run on photosynthesis. The problem is, these sun-soaked  regions are heating up extra fast. But while some other animals can move to cooler waters, there’s no way out for corals.

So, some researchers have started thinking about ways we might keep these areas livable… by setting up a kind of  cooling system for coral reefs. Basically, AC for the ocean. Now, in some parts of the world, the ocean already has a kind  of natural cooling system.

It’s called upwelling, and it’s what happens when colder water from deep down rises up to the surface. Because if you’ve got a bunch of wind pushing aside a warm, upper layer of water, the cooler water that was below that warm water can suddenly rise up to take its place. So that got some scientists wondering if they could create upwelling in certain places and flush colder water through coral reefs.

In theory, they might be able to do this by installing long tubes around reefs to pump up water from dozens  of meters below the surface. Of course, we don’t want to start just messing around with a fragile ecosystem that’s already in crisis, so one team of researchers tested out the idea in tanks. They put three types of corals in water that was too warm for them, but they pumped cooler water through the tank once a day, for one to two hours, to see if it offered the corals any relief.

After three weeks, they took a look at how the corals responded. It wasn’t a perfect solution, and one of the species didn’t fare any better than species in a control group. But the other two did show lower stress responses.

So the researchers are currently testing out longer pulses of even colder water, and running the  experiment for twice as long. And according to them, they’re already seeing some  more promising results. So, in the future, artificial upwellings might offer some relief to  corals on the hottest days.

Another way scientists are trying to preserve these ecosystems is by focusing their efforts  on specific parts of reefs that are most likely to survive. Because for some reason, certain parts seem to be weathering climate change better than others. These areas are called refugia, and scientists aren’t quite sure why they’re so special.

Maybe they have corals with useful genetic mutations, or maybe something about the environment is helping them out. In any case, with a little assistance, the corals in these refugia could potentially survive and hold down the fort until conditions improve, or until we come up with some better solution. The trick is finding these  refugia in the first place.

It’s hard to gauge how a whole reef is doing by studying it up close, for the same reason that it’s hard to see how a forest is doing looking at individual trees. But we can get a pretty good sense of what’s going on underwater by looking from the air. Scientists first demo-ed this with a year-long experiment in Hawaiʻi.

In January 2019, they flew a plane a couple kilometers above the ocean, where they had a bird’s-eye view of its reefs. As the plane passed over top, they snapped images in both  visible and infrared light, and they used a scanning technology called LiDAR to create a topographical map of the area. All of this data gave them a detailed picture of the shape, color, and temperature of the reefs.

Then a year later, after an extraordinarily hot summer, they surveyed the area again. By comparing the observations from one year to the next, they could see where parts of the  reef had died off or grown back, or where the temperature had changed. And that gave them an idea which regions were the most resilient, so they could pick out possible refugia.

It was a successful test, and these scientists hope that installing the same systems onto satellites will make observations like this possible on a global scale. But sometimes it is helpful to get up close and personal with a reef. Because in order to come up  with new ways to save them, we have to really understand what’s happening to them, beyond just noticing which ones are dead and alive.

One way scientists are thinking of doing that is through artificial corals. And we’re talking high-quality knock-offs here… like, realistic down to the cellular level. But that’s not all!

They also have built-in sensors for researchers to keep tabs on all the chemical and biological processes that corals need to do to stay in tip-top shape. So to make these so-called biohybrid corals, scientists are developing a type of technology called bioprinting. So to make these so-called biohybrid corals, scientists are developing a type of technology called 3-D bioprinting.

The process uses living cells to create tissues or even tiny organs that will function similarly to the real ones. This gives scientists the ability to test things they can’t with actual coral. But creating realistic corals is surprisingly difficult to pull off.

You need to create both the tissues and the mineral structure underneath the skeleton. Their tissue is like a layered cake, with each layer having a different function. Some layers have symbiotic algae to help with harvesting energy from sunlight, others have stinging cells for defense and feeding.

The very bottom layer of  cells builds the skeleton. Most corals have a skeleton made of a biomineral called aragonite, which is a type of limestone. This is not from corals though this is from our Rocks Box.

They build their skeletons by extracting the mineral  element out of the water, and this is what builds the reef. To create a skeleton close enough to the real thing that coral cells will live on it in a lab, researchers use bioink that hardens and provides structural support. Then scientists can study the effect of light and other parameters on the sensitive coral cells in order to develop ways to  help them be more resilient.

Of course, monitoring coral reefs isn’t the same as saving real ones. But what we learn from doing it could set us on the right track. We already know none of this is going to be easy.

But remember: we’re a species that can create biohybrid corals, underwater climate control, and monitor the seafloor from space. I think we’re up for the challenge. Thanks for watching this episode!

And a big thanks to ASU’s College of Global Futures, and School of Ocean Futures particularly Yvonne Sawall, Liza Roger, and Greg Asner, whose research informed this video. If you're passionate about marine conservation and coastal ecosystems, you might want to learn more about ASU Online’s Master of Science in Coastal and Marine Science and Management. This program equips students with the tools to develop sustainable solutions and protect vital ecosystems around the world.

Whether you're interested in policy, science, or management, this program has it all. To learn more, click the link in the description! [outro]