Written by Alan Barker, Freelance Writer, British Science Festival 

Coral reefs are facing an unprecedented threat from rising sea temperatures. But the story is not all doom and gloom: Heidi Burdett (the Lyell Centre, Heriot Watt) who’s delivering the Charles Lyell Award Lecture at the 2018 British Science Festival, is on the case.

Alan Barker took the plunge and found out more.

Heidi Burdett will shed insight into how examining the resilience mechanisms of some corals could provide the answers to their salvation

Why are rising sea temperatures such a serious threat for coral reefs?

Principally, because of how corals get their energy. I’m a marine biologist: I study the physiology of coral and algae. Corals are animals, but they exist in a symbiosis with algae, which photosynthesise and provide the corals with their energy. But when the corals become stressed, these algae are expelled, and so the corals lose their energy source. That causes a process called bleaching: they lose all their beautiful colours and become completely white.

And they can’t repair themselves?

Unfortunately, bleaching can damage or destroy a coral reef very quickly, but reefs grow very slowly. They’re huge – the Great Barrier Reef is the world’s largest living structure – but it takes thousands of years to reach that size.

So bleaching kills the reef?

Not necessarily. During a bleaching event, not all the corals bleach nor die. We’re trying to understand the physiology of the more resilient corals so that we might be able to manage reefs better in the future. For example, some corals always live in very unfavourable conditions, whilst others simply don’t bleach, despite being surrounded by others that have.

Do other kinds of impact affect coral reefs – like diving?

They absolutely do. Coral reefs are a fantastic economic resource. Divers pay lots of money to go to them. But divers can have a damaging effect simply by being around the reef. Swimming for example stirs up sand that makes the water cloudier, making photosynthesis more difficult. Balancing the economic advantages of tourism with environmental damage is tough. But we can educate divers to dive safely: take only photos, leave only bubbles.

Divers can have a damaging effect simply by being around the reef.

Do reefs support other industries?

Oh yes. Fishing in particular.  A healthy reef supports a healthy, and economically productive, fish population.

Do you directly engage with these industries?

We do a lot of work in the Maldives – yes, I know, but someone’s got to do it! – where 100% of their income from natural resources is from coral reefs – principally fishing and tourism. We stay and work with local people and local businesses. Local knowledge is always the best way to understand how reefs are responding to change. Whilst we can put down temperature loggers to monitor change in water temperature over a season, the fishermen have been around for decades and they know exactly what’s going on in the reef.

Do they regard you as friends?

I like to think so.

A healthy reef supports a healthy, and economically productive, fish population

Because presumably they have an interest in the reefs surviving…

Absolutely. Scientists and conservationists can sometimes be seen as trying to stop things happening – leaving things alone might be the best choice ecologically-speaking. But that’s often not a realistic solution, because these people are also trying to make a living. Working together, we can help to make their activities sustainable, ensuring their livelihoods are not compromised, whilst also ensuring the reef has the best chance for long-term survival.

Can we build artificial reefs?

That’s not yet been a part of my work, but yes we can. By placing structures on the seabed you provide a base for new corals to settle and grow. We can also select corals that appear to be resilient to bleaching, grow them into multiple corals and then transplant them onto the reef. However, these solutions are very labour-intensive and it takes a very long time to grow a reef from scratch.

Will the new reef be as diverse as the old one?

Possibly. Bleaching doesn’t necessarily kill corals, and if they can get their algae back soon enough, they can fully recover. If some corals survive, but others do not, the make-up of the reef can change.

So we could just sprinkle algae all over the reef and hope that…

I wish! Unfortunately, corals are quite picky; different corals like different algae. And that’s actually something we’re trying to work out: which specific corals like which specific algae.  Kind of like speed-dating for coral!

Resilient reefs takes place on Tuesday 11 September, at 15:00, at Middleton Hall, University of Hull. Book your tickets here