How we're growing baby corals to rebuild reefs | Kristen Marhaver

134,918 views ・ 2015-12-23

TED


Please double-click on the English subtitles below to play the video.

00:12
What was the most difficult job you ever did?
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Was it working in the sun?
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Was it working to provide food for a family or a community?
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Was it working days and nights trying to protect lives and property?
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Was it working alone
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or working on a project that wasn't guaranteed to succeed,
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but that might improve human health or save a life?
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Was it working to build something, create something, make a work of art?
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Was it work for which you were never sure
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you were fully understood or appreciated?
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The people in our communities who do these jobs
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deserve our attention, our love and our deepest support.
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But people aren't the only ones in our communities
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who do these difficult jobs.
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These jobs are also done by the plants, the animals
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and the ecosystems on our planet,
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including the ecosystems I study: the tropical coral reefs.
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Coral reefs are farmers.
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They provide food, income and food security
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for hundreds of millions of people around the world.
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Coral reefs are security guards.
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The structures that they build protect our shorelines
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from storm surge and waves,
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and the biological systems that they house filter the water
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and make it safer for us to work and play.
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Coral reefs are chemists.
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The molecules that we're discovering on coral reefs are increasingly important
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in the search for new antibiotics and new cancer drugs.
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And coral reefs are artists.
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The structures that they build
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are some of the most beautiful things on planet Earth.
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And this beauty is the foundation of the tourism industry
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in many countries with few or little other natural resources.
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So for all of these reasons, all of these ecosystem services,
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economists estimate the value of the world's coral reefs
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in the hundreds of billions of dollars per year.
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And yet despite all that hard work being done for us
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and all that wealth that we gain,
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we have done almost everything we possibly could to destroy that.
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We have taken the fish out of the oceans
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and we have added in fertilizer, sewage,
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diseases, oil, pollution, sediments.
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We have trampled the reefs physically with our boats, our fins, our bulldozers,
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and we have changed the chemistry of the entire sea,
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warmed the waters and made storms worse.
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And these would all be bad on their own,
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but these threats magnify each other
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and compound one another and make each other worse.
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I'll give you an example.
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Where I live and work, in Curaçao, a tropical storm went by a few years ago.
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And on the eastern end of the island,
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where the reefs are intact and thriving,
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you could barely tell a tropical storm had passed.
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But in town, where corals had died from overfishing, from pollution,
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the tropical storm picked up the dead corals
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and used them as bludgeons to kill the corals that were left.
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This is a coral that I studied during my PhD --
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I got to know it quite well.
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And after this storm took off half of its tissue,
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it became infested with algae,
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the algae overgrew the tissue and that coral died.
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This magnification of threats, this compounding of factors
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is what Jeremy Jackson describes as the "slippery slope to slime."
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It's hardly even a metaphor because many of our reefs now
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are literally bacteria and algae and slime.
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Now, this is the part of the talk
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where you may expect me to launch into my plea
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for us to all save the coral reefs.
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But I have a confession to make:
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that phrase drives me nuts.
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Whether I see it in a tweet, in a news headline
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or the glossy pages of a conservation brochure,
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that phrase bothers me,
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because we as conservationists have been sounding the alarms
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about the death of coral reefs for decades.
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And yet, almost everyone I meet, no matter how educated,
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is not sure what a coral is or where they come from.
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How would we get someone to care about the world's coral reefs
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when it's an abstract thing they can barely understand?
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If they don't understand what a coral is or where it comes from,
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or how funny or interesting or beautiful it is,
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why would we expect them to care about saving them?
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So let's change that.
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What is a coral and where does it come from?
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Corals are born in a number of different ways,
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but most often by mass spawning: all of the individuals of a single species
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on one night a year,
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releasing all the eggs they've made that year
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into the water column,
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packaged into bundles with sperm cells.
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And those bundles go to the surface of the ocean and break apart.
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And hopefully -- hopefully -- at the surface of the ocean,
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they meet the eggs and sperm from other corals.
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And that is why you need lots of corals on a coral reef --
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so that all of their eggs can meet their match at the surface.
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When they're fertilized, they do what any other animal egg does:
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divides in half again and again and again.
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Taking these photos under the microscope every year
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is one of my favorite and most magical moments of the year.
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At the end of all this cell division, they turn into a swimming larva --
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a little tiny blob of fat the size of a poppy seed,
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but with all of the sensory systems that we have.
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They can sense color and light, textures, chemicals, pH.
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They can even feel pressure waves; they can hear sound.
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And they use those talents
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to search the bottom of the reef for a place to attach
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and live the rest of their lives.
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So imagine finding a place where you would live the rest of your life
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when you were just two days old.
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They attach in the place they find most suitable,
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they build a skeleton underneath themselves,
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they build a mouth and tentacles,
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and then they begin the difficult work of building the world's coral reefs.
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One coral polyp will divide itself again and again and again,
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leaving a limestone skeleton underneath itself
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and growing up toward the sun.
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Given hundreds of years and many species,
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what you get is a massive limestone structure
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that can be seen from space in many cases,
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covered by a thin skin of these hardworking animals.
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Now, there are only a few hundred species of corals on the planet, maybe 1,000.
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But these systems house millions and millions of other species,
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and that diversity is what stabilizes the systems,
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and it's where we're finding our new medicines.
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It's how we find new sources of food.
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I'm lucky enough to work on the island of Curaçao,
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where we still have reefs that look like this.
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But, indeed, much of the Caribbean and much of our world
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is much more like this.
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Scientists have studied in increasing detail
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the loss of the world's coral reefs,
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and they have documented with increasing certainty the causes.
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But in my research, I'm not interested in looking backward.
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My colleagues and I in Curaçao are interested in looking forward
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at what might be.
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And we have the tiniest reason to be optimistic.
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Because even in some of these reefs
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that we probably could have written off long ago,
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we sometimes see baby corals arrive and survive anyway.
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And we're starting to think that baby corals may have the ability
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to adjust to some of the conditions that the adults couldn't.
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They may be able to adjust
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ever so slightly more readily to this human planet.
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So in the research I do with my colleagues in Curaçao,
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we try to figure out what a baby coral needs
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in that critical early stage,
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what it's looking for
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and how we can try to help it through that process.
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I'm going to show you three examples of the work we've done
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to try to answer those questions.
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A few years ago we took a 3D printer and we made coral choice surveys --
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different colors and different textures,
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and we simply asked the coral where they preferred to settle.
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And we found that corals, even without the biology involved,
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still prefer white and pink, the colors of a healthy reef.
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And they prefer crevices and grooves and holes,
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where they will be safe from being trampled
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or eaten by a predator.
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So we can use this knowledge,
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we can go back and say we need to restore those factors --
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that pink, that white, those crevices, those hard surfaces --
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in our conservation projects.
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We can also use that knowledge
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if we're going to put something underwater, like a sea wall or a pier.
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We can choose to use the materials and colors and textures
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that might bias the system back toward those corals.
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Now in addition to the surfaces,
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we also study the chemical and microbial signals
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that attract corals to reefs.
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Starting about six years ago, I began culturing bacteria
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from surfaces where corals had settled.
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And I tried those one by one by one,
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looking for the bacteria that would convince corals to settle and attach.
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And we now have many bacterial strains in our freezer
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that will reliably cause corals
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to go through that settlement and attachment process.
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So as we speak,
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my colleagues in Curaçao are testing those bacteria
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to see if they'll help us raise more coral settlers in the lab,
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and to see if those coral settlers will survive better
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when we put them back underwater.
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Now in addition to these tools, we also try to uncover the mysteries
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of species that are under-studied.
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This is one of my favorite corals, and always has been:
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dendrogyra cylindrus, the pillar coral.
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I love it because it makes this ridiculous shape,
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because its tentacles are fat and look fuzzy
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and because it's rare.
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Finding one of these on a reef is a treat.
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In fact, it's so rare,
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that last year it was listed as a threatened species
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on the endangered species list.
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And this was in part because in over 30 years of research surveys,
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scientists had never found a baby pillar coral.
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We weren't even sure if they could still reproduce,
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or if they were still reproducing.
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So four years ago, we started following these at night
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and watching to see if we could figure out when they spawn in Curaçao.
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We got some good tips from our colleagues in Florida,
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who had seen one in 2007, one in 2008,
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and eventually we figured out when they spawn in Curaçao
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and we caught it.
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Here's a female on the left with some eggs in her tissue,
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about to release them into the seawater.
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And here's a male on the right, releasing sperm.
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We collected this, we got it back to the lab, we got it to fertilize
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and we got baby pillar corals swimming in our lab.
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Thanks to the work of our scientific aunts and uncles,
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and thanks to the 10 years of practice we've had in Curaçao
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at raising other coral species,
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we got some of those larvae to go through the rest of the process
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and settle and attach,
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and turn into metamorphosed corals.
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So this is the first pillar coral baby that anyone ever saw.
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(Applause)
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And I have to say -- if you think baby pandas are cute,
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this is cuter.
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(Laughter)
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So we're starting to figure out the secrets to this process,
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the secrets of coral reproduction and how we might help them.
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And this is true all around the world;
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scientists are figuring out new ways to handle their embryos,
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to get them to settle,
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maybe even figuring out the methods to preserve them at low temperatures,
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so that we can preserve their genetic diversity
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and work with them more often.
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But this is still so low-tech.
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We are limited by the space on our bench, the number of hands in the lab
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and the number of coffees we can drink in any given hour.
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Now, compare that to our other crises
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and our other areas of concern as a society.
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We have advanced medical technology, we have defense technology,
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we have scientific technology,
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we even have advanced technology for art.
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But our technology for conservation is behind.
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Think back to the most difficult job you ever did.
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Many of you would say it was being a parent.
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My mother described being a parent
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as something that makes your life far more amazing and far more difficult
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than you could've ever possibly imagined.
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I've been trying to help corals become parents for over 10 years now.
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And watching the wonder of life
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has certainly filled me with amazement to the core of my soul.
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But I've also seen how difficult it is for them to become parents.
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The pillar corals spawned again two weeks ago,
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and we collected their eggs and brought them back to the lab.
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And here you see one embryo dividing,
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alongside 14 eggs that didn't fertilize
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and will blow up.
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They'll be infected with bacteria, they will explode
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and those bacteria will threaten the life of this one embryo
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that has a chance.
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We don't know if it was our handling methods that went wrong
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and we don't know
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if it was just this coral on this reef, always suffering from low fertility.
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Whatever the cause,
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we have much more work to do before we can use baby corals
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to grow or fix or, yes, maybe save coral reefs.
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So never mind that they're worth hundreds of billions of dollars.
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Coral reefs are hardworking animals and plants and microbes and fungi.
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They're providing us with art and food and medicine.
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And we almost took out an entire generation of corals.
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But a few made it anyway, despite our best efforts,
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and now it's time for us to thank them for the work they did
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and give them every chance they have to raise the coral reefs of the future,
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their coral babies.
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Thank you so much.
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(Applause)
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