Nestled among giant fish tanks at the California Academy of Sciences, there's a black box—just big enough to hold six aquariums and maybe five humans. What it lacks in size, though, it makes up for in preciousness: Running here is a experiment that could help save corals from annihilation.
The corals in these tanks are reproducing sexually. Which is weird, because even out in the wild, coral spawning is a fragile process, easily disrupted by changes in temperature and acidity. Reproduction has to be precisely timed with the phases of the moon, and it occurs just once a year, as corals release great clouds of sperm and eggs that mix together, fertilize, and descend once more to the seafloor.
Corals are animals, not plants; each organism is made up of lots and lots of polyps. Some species can reproduce asexually, essentially producing clones of themselves. But not the ones in this black box, which are somehow spawning away thanks to some fancy technology and a team of doting humans.