A day in the life of baby coral | ideas.ted.com - 0 views
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The star coral here is preparing to spawn, holding a bundle of gametes in each of its mouths (about 100 of them in this shot). The bright green color at the ends of the tentacles is produced by the coral’s own sunscreen-like pigments while the brown color is produced by the algae living inside the coral’s tissue. The light pink color is the gamete bundles, each made up of 50-100 eggs glued together with sperm. Yes, that’s right… they’re hermaphrodites. Not every coral is, but in this particular species each individual animal makes both eggs and sperm. But one individual coral colony can’t fertilize itself, so it still has to find a partner to mate with. How do you find a mate when you’re stuck to the bottom of the ocean? Most spawning coral species solve this puzzle by sending their sperm and eggs to meet at the water surface, cleverly turning a three-dimensional problem into a two-dimensional one.
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synchronize their spawning times
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dozens of colonies all release their bundles into the water simultaneously
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The egg-sperm bundles are buoyant; they rise slowly in the seawater thanks to the large amount of fat in the eggs
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The sperm and egg cells are only viable for an hour or so,
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he bundles in this picture are just beginning to break up: the tiny clouds of sperm are visible and a few eggs are starting to separate. It’s amazing to see, and humbling to work with; each bundle is the entire reproductive effort for a coral polyp for the entire year.
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Star coral eggs take almost two hours to start dividing after they’re fertilized
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Finally, some of the eggs begin to pinch in half, forming two cells
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At this stage we can score fertilization rates
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The cells keep dividing until they form a hollow ball; this is the “blastocyst” stage
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At this point in the night we can even FEEL the biology happening: the temperature in the lab goes up from all the biological activity going on.
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opying all of their DNA every 40 minutes
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The next morning, the embryos have developed into larvae
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By the afternoon, they have truly learned to swim
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The corals have now gone through the full settlement process including attachment, metamorphosis (growing their tentacles, mouth, and digestive system), and are beginning to grow their skeletons (the small white cups).
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The species only grows about a half an inch a year, so this colony is probably three or four years old.
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he star coral here could be over 500 years old s
