Honolulu - coral bleaching and an optimistic scuba instructor called Ollie

December 14, 2017

Wed 6th - 21km

Thurs 7th - 21km


I arrived in Honolulu at about 11pm on Tuesday where my Air BnB host named Star was waiting for me at the airport in her blue Ford pick-up. When we got back to the accommodation, Star apologised for the mess in the lounge, explaining that she had spent all week moving house. “I’ve had a huge clear out – I had to bin half my stuff” Star told me. I queried whether the three large metal buckets full of what looked like acorns and the collection of coke bottles (those ones with people’s names on them) had some sort of sentimental value, having appeared to have made it into the top half of Star’s possessions. “Oh no that’s not mine - that’s Greg’s work stuff – he keeps it here as he is in-between jobs at the moment”. What jobs this unknown man called Greg, who appeared to be in the industry of manufacturing personalised nutty-flavoured cola, was in-between, remained a mystery.

I ran two half marathons, both along pristine coastline, during my 48-hour stop-over in Honolulu. I was pleasantly surprised at how beautiful and untouched the beaches were, considering the size of the city and the considerable development that has occurred along its shores.  From a height, as you look directly down at the translucent blue water, you can see the dark shadows and outlines of the coral reefs that lie just below its surface. The corals that make up these reefs are alive and they are unlike any other species on earth. They have the ability to build their own environments and create their own habitats, colourful and vibrant 3D cities, where every fish has its own unique home. Hawaii itself has over 2000km of coral reefs.


A piece of coral is alive and is made up of thousands of small structures called polyps (a small circular mouth-like thing covered in tentacles). Inside the tissues of those polyps are tiny little plants called microalgae, which are what gives the coral its colour. These plants photosynthesise inside the polyps and the coral uses the carbohydrates produced from the photosynthesis, for food. Essentially, they have tiny little food-factories located inside them. This coral animal grows over a skeleton, and as it grows, it deposits more skeleton underneath it, expanding in size. There are a number of different species of corals and together they make up a reef. 


However, corals here and all around the world are dying. In the last 30 years, we have lost 50% of the world’s corals. When carbon is realised into the atmosphere, it traps heat, causing temperatures to rise. What is not so well-known, is that 93% of this heat is being absorbed by the ocean. Like most species, corals only have a limited temperature range in which they can survive. If the temperature spikes just a little bit above their normal range, corals will start to bleach. In this region, two thirds of the north-western Hawaiian Islands are seeing a level of warming that would usually trigger bleaching. 


Bleaching occurs because the tiny plants that live inside the coral find it hard to photosynthesise and make food. The coral senses that these small plants are no longer functioning properly and gets rid of them, essentially ejecting its internal food source and the organism that gives it its colour. What you are left with is a translucent skin and a bleached white skeleton underneath, with the corals in a sort of dormant coral-coma. Although the coral is not dead, it cannot live for long without its internal food source. So, unless favourable environmental conditions return pretty quickly, the coral dies. There is an amazing 2017 documentary available on Netflix called “Chasing Coral”. It follows a group of scientists and coral-lovers as they dive every day for a month and a half, manually capturing the death and bleaching of certain areas of coral along the Great Barrier Reef and its surrounds.  Here are some of the startling pictures showing the reefs when they arrived compared to just 45 days later:


The death of so many corals around the world is extremely concerning. Coral reefs are an essential habitat for around a quarter of all marine species. Because of this they are a particularly important resource for local communities, providing a critical food source as well as a revenue stream through tourism. Small island economies have grown to rely on coral reefs (the Hawaiian reefs generate about $800 million a year).  Further, corals provide a natural and often essential breakwater providing small islands with a form of natural protection from tropical storms and hurricanes. Even some cancer-fighting drugs come from coral reefs.


 From 2014 to 2016, nearly 50% of the corals in Hanauma Bay Nature Preserve in Hawaii bleached and almost 10% died. I ran out to Hanauma Bay (which was annoyingly a little further than 21km from Honolulu) to check this out. I asked scuba-instructor Ollie, at Hanauma Bay snorkel rentals, if he had noticed a difference in tourism due to bleaching. “Well, I suppose it’s increasing in the fact that you came here just to see the bleached coral”. Cheers, Ollie. That was the opposite answer to the one I was looking for.


Snorkelling along the coast I saw a number of colourful fish species, but also a number of white coral structures. Truthfully, my animal biology 202 paper didn’t provide me with the requisite training to tell the difference between bleached coral and coral that is just normally white…. But regardless, the lack of underwater colour was definitely apparent. I can’t really show you pictures of this as all my footage seems to be unflattering, up-close, selfies or underwater rocks.


And if you don’t trust the results from my ill-informed 15-minute snorkelling excursion, the appalling statistics should speak for themselves:

  • 25% of the Great Barrier Reef died in 2016 alone. One-quarter of the Great Barrier Reef – gone in a year.

  • Scientists claim that we have lost 80 – 90% of coral in Florida. What used to look like a colourful underwater garden is now just a coral graveyard – the skeletons are still there, but the life has gone.

  • The once vibrant Airport reef in American Samoa is now white as far as the eye can see. This change literally occurred over a number of weeks.

  • Mexico, El Salvador, Costa Rica, the East Texas Flower Gardens, French Polynesia, Vanuatu, Bali, Sri Lanka, Thailand, Tanzania, Egypt, Japan and more have all experienced mass bleaching events.

This is not a natural cycle, it is something directly attributed to climate change, and something that we have only started seeing in recent years.[1] Based on current trends, in the next 30 years bleaching will kill most of the world’s corals. This means that we will see the eradication of an entire ecosystem in our lifetime. The destruction of some of the most beautiful natural structures on earth, will be completely on our watch.

This will have disastrous consequences on so many aspects of the natural environment and on human life. However, at least coral bleaching is having a positive effect on Ollie at Hanauma Bay snorkel rentals, who has seen tourism numbers up by one.


[1] The first global mass bleaching event occurred in 1998/1999 with the second occurring around 12 years later in 2010.


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