Great Barrier Reef coral to release trillions of eggs in mass breeding event

ABC NEWS (Australia)

The Great Barrier Reef's annual coral spawning is underway, with the reef's corals releasing trillions of eggs in a mass breeding event. A team of scientists are on site to try to help things along, aiming to feed the baby coral to boost its chances of survival. Dr Jen Matthews is leading the team.

Transcript

00:00It's one of nature's most amazing events. It happens just a few nights of the year after the

00:08full moon and the corals all release their eggs and sperm into the water. It looks like it's snowing

00:14upside down. It's quite spectacular. And then the eggs and sperm float to the surface where

00:19they fertilise and then over the next few days create little coral larvae which then swim down,

00:25find a nice new place to live and cool home and create a new coral. And so without this our reefs

00:31would not exist? That's absolutely right. This is a really critical thing for coral reefs to

00:36both rebuild degraded reefs, expand their reef structures and even establish new reefs in new

00:43areas. Without your help, what is the chance of all of the corals surviving during this mass spawning

00:50event? That's a great question. So corals release millions of eggs but actually typically less than

00:56one percent survive which is a really big bottleneck when we're considering the rate of coral loss on

01:02our reefs. And so to help facilitate that we've created this kind of nutritional supplement or

01:07a coral baby food if you would to help boost their life and fitness during those vulnerable early life

01:14stages. So we tried it in the lab and we found it doubled their survival and now we're taking it to

01:20the reef to see if it does the same thing. And how does it work? Is it much like you know if you have a

01:25pet fish and you feed that in the morning and in the afternoon you sprinkle a little bit of food on

01:30top? How does it work for you? Yeah unfortunately they don't make baby bottles quite small enough to

01:35coral larvae. So what we do we actually fill them with something called a lipid nanoparticle. It's

01:40tiny little balls of fats and the larvae have a small paw a small mouth that they can eat

01:47particulate matter from the water and so they take in these little nanoparticles and that's how we

01:53deliver the food. Yeah right how do you deal with though you know tides and waves and being washed away

02:00and then being only a very small part in a very large ocean? That's a really good question like the

02:06larvae are used to or I guess the corals are used to reproducing in the turbulent waters of the ocean

02:11and so they have built mechanisms to do that. As they say they float over the next couple of days that

02:17helps to avoid any of the banging into the reef structures but it is a really vulnerable life stage

02:24they're just essentially balls of dividing cells so they're really fragile at this point. I read that

02:30you refer to your fantastic team of coral midwives. Is that what you basically are in the marine world?

02:38That's essentially that's right we are the coral midwives for the next week in our little coral

02:42NICU lab looking up at millions of corals. Yeah that's right. So we hear so often Jen about high

02:50sea temperatures coming our way, clot coral bleaching coming our way. Just how important is it that we

02:57understand, nurture and protect these spawning events? That's absolutely right. They're facing so

03:03many different pressures both local and global so they've really got kind of the world against them

03:08at the moment. Our reefs when they're reproducing that's a really great sign that they're healthy

03:13enough to reproduce and they're cycling but it is one of those points where the water at the moment is

03:20a few degrees warmer than it normally is this time of year which is a positive sign. We may experience

03:25another mass bleaching as we get into summer and so having these new baby corals is really important

03:31because it allows for evolution to do its thing and hopefully some of these ones that we're giving

03:37a kickstart to life will survive into the future and be more resilient and provide a more resilient

03:43reef. And Jen given that you're up there and you're spending a lot of time there on the reef

03:47how would you characterise the state of the reef? It's looking absolutely beautiful at the moment but you

03:53can see a number of dead skeletons on the reef that have died recently and as well over the last

03:58couple of years so there's really quite a few evidence of stresses on the reef.

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