On a clear, calm night in the waters of Australia's Great Barrier Reef last week, local photographers slipped into scuba gear, grabbed underwater cameras, and dove into a colorful underwater snowstorm.
The corals were growing.
Video clips show coral spawning in the Great Barrier Reef.
Nick De Gabriele is a producer for Calypso productions.
We're looking at all the beautiful coral colonies and just watching the little parcels of sperm and egg. "Then all of a sudden, they just erupt, kind of like a smokestack going up, but made up of tiny pink balls drifting up to the surface," said a marine biologist who has observed corals for 10 years.
Corals are colonies of animals. They open up and release millions of eggs and sperm in a breeding event.
It's the largest sexual event on the planet.
In the past, spawning events have either been a trickle or a mass explosion. He said that this year it was like a bunch of different corals releasing their bundles.
"There seemed to be different species spawning in waves, one after the other," saidPhillips, who runs Reef Teach, a tourism and research center. It's gratifying to see the reef give birth.
Eggs and sperm will be released in the Great Barrier Reef.
Gabriel Guzman/Calypso productions.
The photographers captured amazing photos and footage. Many of the divers who have watched parts of the reef die off over the last few years were happy to see the breeding frenzy.
Warming oceans threaten corals everywhere.
sperm and eggs will be released in the Great Barrier Reef.
The teacher is GarethPhillips/Reef Teach.
Humans have pumped carbon dioxide into the atmosphere for more than a century, raising the temperature and acidity of the oceans. Corals look white when they don't have algae, and this is known as "coral bleaching." Corals expel colorful algae that live on them and serve as their food source. Corals can be killed by bleach, but they often die after.
The Global Coral Reef Monitoring Network (GCRMN), in collaboration with the United Nations, published a report last month showing that rising ocean temperatures caused the death of 14 percent of the world's coral.
That's more coral than all of Australia's reefs.
The coral is in the Great Barrier Reef.
The teacher is GarethPhillips/Reef Teach.
Reefs have recovered from coral damage before. The 1998 global bleaching event killed 8% of the world's coral, but the reefs recovered to pre-1998 coral cover during the ensuing decade according to the GCRMN report.
The 2010s were warm enough to cause back-to-back global bleaching events, which killed more coral than was killed in 1998. The Great Barrier Reef had its worst ever bleaching events in 2016 and 2017.
Terry Hughes, director of the Centre of excellence for Coral Reef Studies at James Cook University, told CNN at the time that they were all in shock. Three severe bleaching events in five years is not something we anticipated until the middle of the century.
The coral is in the Great Barrier Reef.
The teacher is GarethPhillips/Reef Teach.
This year's explosion is cause for hope forPhillips.
The Washington Post quotedPhillips as saying that the event is a great showcase.
25% of the planet's marine animals and plants are found on coral reefs. According to the GCRMN report, they provide food, jobs, recreation, and a buffer against coastal flooding for hundreds of millions of people.
This is why we need to look after it.
The Great Barrier Reef has coral spawning.
Gabriel Guzman.
Scientists don't know what causes corals to grow, and they can't predict when it will happen.
In the northern Great Barrier Reef, corals usually start to grow in November or December after the full moon. The water must be warm enough for eggs to mature in the weeks before spawning. The Great Barrier Reef authority says that the events are linked to the tide, length of the day, and saltiness of the waters.
"While we are able to predict a time when it might happen, so much about this annual event is still a mystery," saidPhillips.
