Fresh Hope for Dying Reefs: Coral Sperm Bank

Corals are coming under stress, reefs are shrinking - and these scientists had an idea how to help.

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Coral is an animal, albeit a primitive one, and it proliferates through sex – through their intercourse is remote. Every year, when conditions are optimal, the corals of Australia's Great Barrier Reef release billions of eggs and sperm into the ocean.

The gametes meet by the chance motion of the water, and where they come together, new colonies form.

But the cycle of reproduction going back hundreds of millions of years is now being overwhelmed by environmental factors that have decimated the coral over the last several decades. The reefs are shrinking at an alarming rate, and one group of researchers say a radical response is needed if the corals are to be saved from extinction.

Their solution: A coral sperm bank, led by Doctor Mary Hagedorn of the Smithsonian Institution. The technology is the same as that used to preserve human sperm. Coral samples are collected and deep frozen in liquid nitrogen where they'll be stored indefinitely.

"The idea was to bring cryopreservation technology to the Great Barrier Reef," Hagedorn says. "It creates a coral fertility clinic." And when needed, these coral cells can be used.

Their dearest hope is that the bank won't be necessary, and that the imperiled reefs will recover on their own. But it pays to be prepared, says Dr Rebecce Spindler of the Taronga Conversation Society, adding that the team is making progress.

"We've just collected our sixth species to be added in the bank, and that makes this the biggest cryopopulation in the world apart from humans," Spindler says.

The researchers say that preserving the corals in the Great Barrier Reef could also help protect countless other species that depend on the reef for their own survival.
In fact, coral has been coming under stress the world wide.

Here in Israel, the most famous (and only) reef is in Eilat – where it has been suffering from tide extremes. In September last year, for instance, an extremely low tide earlier exposed part of the coral to the sun. Over time such exposure is fatal to coral.
Until a few years ago, the nature authority’s staff would wet the coral to protect it. Ecologists would sail along the exposed part of the reef, creating a wave that helped protect the reef from the sun.
But in recent years, the nature authority decided not to interfere with the natural process and let the coral face the environmental changes alone.

Corals off the coast of Norway.Credit: Reuters