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May 29, 2017 | by  | in Features |
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Coral Reefs: The Responsibility of Science, or Society?

On December 26, 2004, a massive earthquake and cycle of tsunamis now known as the Sumatra-Andaman event devastated much of Southeast Asia. Coastal communities, especially in western Indonesia, were inundated with walls of water up to 19 metres high that penetrated over two kilometres inland. The death toll was (conservatively) estimated at 230,000.

West of the epicentre, and in the direct path of the radiating tsunamis, lies the small island nation of the Maldives. Despite sitting barely a few metres above sea level, they escaped nearly unscathed. Damage was limited to a few outlying islands; the death toll was considerably less than nearby Sri Lanka, and just one third that of Somalia, which was over 3000km further away from the tsunami’s source. How could this low-lying set of islands escape major damage, when surrounding mainland populations were nearly annihilated?

The answer is coral reefs. To many, they are nothing more than an abstract marine beauty, devoid of function or practicality. But the numerous surge channels and rugged nature of corals buffer storms and large waves, protecting the land beyond. The Maldives, with their complete surrounding coral reef system, thus sustained much less damage than countries with more degraded reefs, like Indonesia and Thailand.  

For people who respond to more financial persuasion, corals reefs were estimated (in 1998) to be worth $375 billion annually. They support tourism and encourage economic development in numerous countries, and are a crucial protein sources for millions of people (one third of commercial fisheries in Indonesia are conducted on coral reefs). In terms of value per hectare, coral reefs are the most important ecosystem on the planet.

But corals are dying.

***

Corals are recognised for their brilliant, variable colours and complex three-dimensional structure. However, this state is becoming increasingly atypical. Beginning in 2014, a massive bleaching event extended across the Pacific and Indian oceans, stimulated by an El Niño (basically a hot round weather ball). The El Niño hit its peak in 2015, decimating corals of the Great Barrier Reef where up to 90% of corals bleached. Significantly, this event also extended to the Indian Ocean, which had previously escaped massive bleaching.

The reefs of the Maldives, that had saved so many lives a decade earlier, suffered bleaching described by the surveying scientists as “haunting.” When corals bleach, their colours disappear and they become a ghastly white. It also makes them more susceptible to strong waves and other stressors, and this weakness leads to frequent breakages. The result of this is what is known as coral rubble: a haphazard assortment of off-white coral bits laid across the bottom, a far cry from the gorgeous assemblages they can be.

Inside the cells of coral live small algae called symbionts, photosynthesising and providing up to 95% of the nutrients that corals require to survive. In extreme temperatures, this association breaks down and the symbionts are expelled: this is the mechanism behind bleaching and the reason for the appalling colour loss. Deprived of their major nutrient source, the corals will soon die.

El Niños, like the ones that caused the mass bleaching, are natural weather events, but in recent years they have become increasingly severe thanks to climate change. Some people (read: ignorant fools) object to the severity with which scientists treat this issue. They say that the world goes through temperature cycles, that it has been this hot before and corals adapted. All of this is true. So why can’t they again?

The issue is pace. The rapidity with which average sea surface temperature is increasing leaves evolution no time to work. More favourable versions of heat-related genes in both corals and symbionts would need to develop (for example through mutation), and then be able to proliferate through coral communities. Additionally, while there are different species of symbiont, corals often host only one specific type — they can’t just pick up random new symbionts, however beneficial they may be. Dealing with all these variables has been manageable for corals in the past, in the 10,000 year thermal cycles of the natural world. But the 50% increase of CO2 in the atmosphere in the last 100 years, and the associated temperature rise, means that evolutionary change is made redundant.

However, evolution can be fast-tracked. Hybridisation (sex and subsequent offspring between two different species) is a rapid way to make new genetic combinations, potentially allowing for the production of more thermally resistant coral types. This could also help corals take up better symbiont types — if half the genes come from a symbiont they would normally associate with, they may be more inclined to accept it.

And so in April I found myself travelling to Atauro Island, to explore the potential for symbiont hybridisation on the coral reefs there. Atauro Island is part of Timor-Leste, a small, recently independent country just north of Australia. This locale was chosen for two reasons. Firstly, some previous evidence of symbiont hybridisation has been found, but it was from Lord Howe Island — an atypical, low-latitude reef. Timor-Leste sits in the heart of the coral triangle, and so evidence from there is more widely applicable to other reefs. Secondly, Conservation International has recently named Atauro Island the most diverse reef fish community in the world, and the reefs there appear to be in pretty good nick (they have avoided much of the devastating bleaching that has occurred elsewhere). It will be useful to assess the diversity of symbiont communities there, and see if there is anything special going on. Actually, there’s a third reason too — who wouldn’t want to go do fieldwork in a tropical country?

***

Atauro Island lies roughly 30 kilometres north of Dili, the capital of Timor-Leste. Flying into Dili, I got a great view of where I would spent the next fortnight, and was struck by its emptiness. There are a few scattered villages on the east and west coasts, a mountainous centre, and that’s about it. At that distance, I could see no evidence of infrastructure at all, which gave me a clue as to why their reefs are so high-quality. The reefs are visible from the air — rippling patches of pale blue-green encircling the island, with an occasional flash of reflected colour, even from a kilometre away. Anybody who has flown over a reef will know this description hardly does justice to their aerial appearance. Crossing over the Banda Sea from Dili, the effect of the reefs was immediate — the choppy water abruptly became placid and glasslike as we neared Atauro Island, the reefs beneath the boat buffering and absorbing the waves.

I really didn’t know what to expect. Timor-Leste has had a turbulent recent history, fighting for independence from Portugal and Indonesia until 2002, and then more internal conflict until 2006. As such, the international scientific community has been largely excluded from the ecosystem until very recently. So in my preparation for the trip I found that literature on what may be out there was largely lacking.

I have had the privilege of snorkelling coral reefs in Rarotonga, Indonesia, and Australia, but the Atauro Island reefs were the best I’d seen by far. A couple of the sites we visited were the first I’d experienced where a coral reef was just all reef. There were no empty sandy patches, no coral rubble, just meadows of hard and soft coral as far as you could see. Also amazing was the diversity. Most reefs around the world have a few dominant species which appear again and again (normally of the genus Acropora). Here, every coral you saw was a new one.

This suited us well — we wanted to sample as much diversity as we could. One of us would go down and sample a small bit of the coral with a trusty pair of pliers, gently snapping off an end of a branch. For the rounded brain corals, a chisel was also used to chip away a small part of the base. The other person would take a photo so the coral could be identified later. These photos were taken up close (within 20cm) as many corals can only be identified through tiny variations in their skeletons.

This sampling method has caused a sticking point among many of my friends — surely I shouldn’t be taking small bits of coral if I am trying to save them? But the bits we were taking were tiny and ecologically insignificant — an M&M size or smaller, from colonies bigger than most people. And anyway, that’s an entirely useless point of view. It’s like saying you shouldn’t send up weather balloons to monitor global patterns because that will add a tiny amount of greenhouse gas to the atmosphere. Attitudes like that will get you nowhere.

After a full day sampling, we would add our coral bits to a DNA buffer — a liquid that keeps DNA stable, preserving samples until they can be processed properly. Following our week on Atauro Island, we travelled back to Dili, the capital of Timor-Leste. Shaun’s wife is a diplomat, so we stayed in a diplomatic house for the next week. I spent the majority of the time in the spare bathroom. No, I didn’t have some hilarious stomach bug — Shaun had set up a pretty thorough DNA lab in there. I extracted DNA from all our coral samples (600 of them), and brought the DNA back to New Zealand. Back here, I will do a whole lot of laboratory stuff, and hopefully be able to provide some useful comments on symbiont diversity, hybridisation, and how corals can best be helped.

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Corals from top to bottom: Galaxea fascicularis (‘octopus coral’); Montipora (unidentified species); Echinopora lamellosa (‘hedgehog coral’); Acropora millepora; Acropora (unidentified species). April, 2017. Atauro Island.

***

After visiting Indonesia and now Timor-Leste, I feel a little cynical about my sort of research. Increasingly I feel it’s like choosing to study a surgery textbook when someone is bleeding out in front of you. Climate change will harm coral, sure. But I have witnessed so many immediate impacts that are happening right now.

Litter physically abrades coral, and blocks light which stops the symbionts from photosynthesising. In Indonesia, I did a brief study of plastic on a reef near Jakarta — along one 50m transect, I counted 28 bits of plastic floating in the water. That was not per any unit area, that was just direct line of sight along 50m. At one point, a full-size discarded mattress, which had been carried by the current from Jakarta, slowly sank before my eyes and nestled among the coral. I will never forget that sight. Even on Atauro Island, with its tiny population, many of the beaches around the villages were covered in trash.

In order to compensate for lowered fisheries takes thanks to previous overfishing, increasingly destructive fishing practices are utilised. Bomb fishing is common, where “fishermen” simply throw dynamite over the side, killing swathes of fish which can easily be collected. The scars left on coral are abysmal to behold.

Even tourism, so important in developing economies, can be harmful. Inexperienced snorkelers kick the reef and can knock off whole branches, something I witnessed even in Australia where tourist education is a high priority.

As part of our sampling, we employed a Timorese man called Ricky, who helped us manage our gear and communicate with local chiefs. He was lovely and chatty. He told us about the history of Atauro Island, about his wife and children, about local customs. He told us how both his parents were tortured by the Indonesian authorities, and how he was born in an Indonesian prison. There are more pressing issues for some, than the degradation of coral reefs.

***

However, the overarching threat of climate change lingers over coral reefs. Despite their social issues, nations are acting in recognition of this fact. Last year, a forum was held in Lautoka, Fiji, to galvanise local action on climate change and to highlight to the international community that they will not give up their coral reefs without a fight. Programs of a similar theme are underway all around the Pacific. Samoa worked with Conservation International to produce a radio show that aired nationwide about the importance of the reefs and the threats they face. In Rarotonga, there has been a recent reintroduction of Ra’ui — traditional locally managed areas. These programs combine the knowledge of international scientists with locals, to bridge the gaps between science and society.

Our research in Timor-Leste was featured on the New Zealand Embassy Facebook page to communicate both the beauty of what we found and the danger that climate change poses. These programs are a start, but consistent collaborative action is required to ameliorate the greatest threat reefs have ever faced.

At this point, I would like to offer something substantive. Something constructive that you or I can do to help. But I can’t. There is no easy fix, no simple action that can be taken to save reefs. Without a global response to climate change, there will be no reefs left to save. All I can do is try to raise awareness through my channels of the myriad issues that face corals. All I can do is highlight that social issues are as prevalent as scientific ones, and often these need to be addressed first. All I can do is try help corals adapt to climate change, and hope there are still enough reefs alive for it to count.

Sunset. April, 2017. Atauro Island.

Sunset. April, 2017. Atauro Island.

 

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