Posts Tagged ‘Coral’

Diving in the Maldives

Sunday, September 13th, 2009
whitetip reef shark (Triaenodon obesus)

whitetip reef shark (Triaenodon obesus)

The Maldives claims to be the place where “even the sharks are friendly”. I’m not too sure I’d want to meet a ‘friendly’ shark, I’d settle for ‘indifferent’. In my experience, the sharks in the Maldives are definitely that, I’ve seen several dozen and they’ve never shown the slightest interest in me. That’s not the only reason why the Maldives is a fantastic place to dive, though it certainly helps. If you’re thinking of going there for a diving holiday, I can recommend it.

I’ve visited four islands on diving holidays, some of them two or three times. I learned to dive with Sea Explorer, at Reethi Beach (Baa atoll), back in 2000. I’ve dived at Machafushi (Ari atoll), where they have an impressive wreck, deliberately sunk on the house reef. I’ve also dived with Ocean-pro dive-team, at Coco Palm (Baa atoll) and Mirihi (Ari atoll).

It has to be said, none of the websites for the islands or their dive-schools do them justice. They are very pretty to look at, but don’t really give any idea of what it’s like to dive in those places. Hopefully, I can go some small way to filling that gap, with this and future articles.



The Maldives is a great place to learn. Shallow lagoons make for easy first lessons, and warm waters mean no messing around with thick wetsuits. The resorts all have a large variety of dive-sites to choose from, normally with a good range for all levels of ability and all interests, from beginner to expert diver. Many (if not all) of the resorts are PADI dive-centres, though I believe they also accept most other internationally recognised certificates. Your tour-operator can probably check for you if you are in any doubt.

Although PADI certify divers to 40 metres (120 feet) (with the Deep Diver certification), the Maldives imposes its own limit of 30 metres (90 feet). Diving below that is not permitted in order to limit disturbance to the environment. That’s not really a handicap, there’s plenty to see in that 30 metres. That said, it’s true that the scenery does change with the depth, and if you are limited to shallower depths by your certification, you might want to consider taking an extra course while you’re there, to get the full value from your dives.

lionfish (Pterois Volitans) at Kihaa Rock

lionfish (Pterois Volitans) at Kihaa Rock

You can dive on the house-reef of your resort, but most of the diving happens from boats. Depending on your resort, there may be one or two boats in the morning, and one or two in the afternoon. Reethi Beach, for example, run two boats in the morning, one which leaves early and does two dives (with an hour’s rest between them) and one which leaves later, doing only one dive. That lets you choose the pace you want for your holiday.

You have to sign up for the boat you want the day before, so they know how many people to expect. Places are limited on each boat, and some popular dive-sites get fully subscribed quickly, so depending on how fanatical your fellow holiday-makers are, you may have to be quick! If you miss out on a site you wanted to visit, just ask the dive-centre. They’ll be willing to re-schedule it soon enough, after giving a day or two to avoid over-diving at the same site, and you’ll get your chance.



Some resorts, Coco Palm is one of them, also organise all-day trips. The boat leaves Coco Palm early in the morning and takes in three dive-sites. You eat lunch on board, and because it’s a longer trip, you get to go to some of the farther sites, places that you might otherwise not get to. It can be quite tiring, but it’s great fun!

House reefs can also be a lot of fun. If you want a rest from the boats, a house-reef is a more leisurely dive. In fact, the house reef at Machafushi is the place I’ve dived at most in the Maldives. The ship sunk there attracts a great deal of life, and it was always a pleasure to dive there.

For first-time divers, there are a couple of specific tips I can think of. These apply anywhere, not just to the Maldives. First, if you’re hiring equipment from the dive-centre, check the pockets of your BCD when you collect it, in case there are extra weights in them. It’s quite possible that the previous user had bouyancy problems, in which case his or her instructor may well have put an extra kilo of weight in the pockets to help them. If they forgot to remove that weight, it could upset your own diving.

black cheeked moray eel (Gymnothorax Breedeni)

black cheeked moray eel (Gymnothorax Breedeni)

Second, if you’re assigned an instructor or divemaster to follow, make sure you know what they look like. That sounds trivial, but if you’re on your first open water dive, it’s quite possible to forget that, for example, your instructor is bald, and discover that the person you are following is not. Yes, I did that! Some instructors make a point of having mis-matched fins, one blue and one yellow, for example. This makes them easy to identify underwater.

banded boxer shrimp (Stenopus Hispidus)

banded boxer shrimp (Stenopus Hispidus)

Such mistakes are probably very rare, and you should not be put off from diving because I mention them. For divers of all levels, the Maldives has a lot to offer. There’s the big stuff, sharks, mantas, morays, fish and corals, which are always fun to see. But there’s also a lot of small stuff hidden away, and it’s a great incentive to improve your diving. Many of the smaller creatures live in small holes or under ledges, and you need good bouyancy control to be able to approach them without disturbing them or damaging the reef. I personally prefer looking for the smaller creatures, and find that diving slowly and close to the reef is more relaxing than swimming hard to cover a lot of ground.

The Maldives is a place where strong currents can occur, and some of the best diving is to be had where the current runs fast. Small fish come out from the reef to feed, big fish come to feed on the small fish, and corals will sometimes open, even during the day. Fighting against a current is hard work, so unless you know how to stay close to the reef and minimise your exertions you may soon find you are using up your air too quickly, or that you have reached the end of the reef early.

strong current at Anga Faru, Baa atoll (note the bubbles streaming away to the right!)

strong current at Anga Faru, Baa atoll (note the bubbles streaming away to the right!)

Either way, your dive will be over, and you will be back on the boat while other people are still enjoying their dives. Of course, if you’re going to stay close to the reef, you need to be very careful not to damage it, so you need to know what you are doing. The dive-centre staff will be happy to give you tips (thank you Robert Schneider!), and you should take every opportunity to talk to them and learn from them.

Even if you are certified to dive on your own, you may want to follow the divemaster or instructor, at least for a few dives. They will know the best places to look for small creatures and interesting things, which can help you learn how to find things for yourself. If you are more confident, heading out on your own away from other divers (but always with your buddy!) means there will be less people near you disturbing the animals you are looking for, which may make them easier to find.

One thing you really must try, even if you are a beginner, is a night-dive. The boat will leave around sunset, and you enter the water as twilight descends. You can still see where you are going and get your bearings, so there’s no difficulty in orienting yourself. Soon, the light disappears, and you and your buddy are left with your torches to explore a reef that looks very different to its daytime appearance. I once dived on the reef at Thiladhoo, in Baa atoll, in the afternoon and night of the same day. They could have been two completely distinct reefs, things were so different. Oh yes, I thoroughly recommend night-dives!

anthias and reef, Ari atoll

anthias and reef, Ari atoll

If you are planning to visit the Maldives in winter, you should consider getting flu vaccinations well before you fly. The last thing you want is to be paying 5-star rates to stay in bed with a cold, and you certainly can’t dive with a congested nose.

For a diving holiday, you will need at least two weeks, one week is just too short. You need a day to get over the jet-lag of getting there, and you can’t dive for 24 hours before your return flight, so a week just wouldn’t give enough time to dive.

More importantly, once you’ve dived in the Maldives, you’ll want to do it again. Even as you board the plane to come home, you’ll be trying to figure out when you can come back again. Take my word for it. Or better yet, don’t take my word, go there and find out for yourself!

World Oceans Day, June 8th

Saturday, June 6th, 2009

The Aegean

The Aegean

Next Monday, June 8th, is World Oceans Day. At the risk of turning this blog into a diary of global eco-events, I’d like to draw your attention to it.

The idea to have a world-day for the oceans came in 1992 from Canada, at the Earth Summit in Rio de Janeiro. It’s been celebrated every year since then, but this year marks the first time it has official U.N. recognition. Henceforth, World Oceans Day will be celebrated on June 8th, every year.

You might think that since I live near Geneva, about as far away from the sea as it is possible to get in Western Europe, I would not have much to say about the sea. If you think that, you must be new to this blog (welcome!), the sea is one thing I can talk about for hours. I grew up in England, closer to the coast than most people there. Nobody in England is more than 70 miles from the sea, I grew up much closer than that, about one mile away from the shore, on an island, no less. I spent many a childhood summer day freezing in the cold water, picking my way over the stony beaches, trying to see what I could through the opaque grey-green waters of the north Kent coast (not much, as it happens). I collected foraminifera (tiny shells, less than 1 mm across) and looked at them under a microscope. I remember the first time I saw sea-anemones, on the beaches of Jersey on a family holiday. I’ve seen octopus and nudibranchs on crowded Greek beaches, and sharks and dolphins in the Maldives. Oh yes, I can safely say I love the sea.

The oceans are huge. They cover almost three-quarters of the surface of the earth, and something like three fifths of the earth is over a mile below the surface of the sea. There is an awful lot of seawater out there. So why do we need a world-day event to draw attention to the oceans? Well, as it turns out, the seas and oceans of the world are not in good shape, and it’s our fault, again. You can find out more about the threats to the oceans on the Marine Conservation Society website, here are a few of the highlights.

Everyone knows about global warming, and the melting of the polar ice-caps. That’s bad news for penguins and polar bears, but also for people. A large fraction of humanity lives near the coast, making a substantial part of their living from what they can haul out of the sea. Rising seas and warming waters will change that. Not only will islands and low-lying regions be lost under the waves, the ecosystems at the coastal fringes will suffer too. Coral reefs, for example, provide living space and nurseries for a great many species, and are essential to the marine environment. Even creatures that don’t live on or in them directly often depend on the animals that do. Excessively warm water leads to ‘coral bleaching’, which can kill it if the water stays warm for long enough. Bleaching events are more common than they used to be, and are predicted to become much worse over time. Despite some research showing that some corals may adapt to warmer waters, there is strong reason to believe that most corals will be killed by warm seas by the end of this century unless we make big cuts in our emissions of greenhouse gasses. Scientists are working to find ways to help coral survive, but they’re racing against the clock.



Globally, there’s an even bigger threat, ocean-acidification. The oceans absorb a great deal of the excess carbon dioxide that we are pumping into the atmosphere, and this is slowly turning the seas more acidic. This slows coral growth because it is harder for the coral to form its chalky skeleton. Other creatures, many of which are right at the bottom of the marine food chain, will suffer the same fate. Acidification of the oceans is a global problem by its very nature. It will affect reefs and other ecosystems worldwide, not just those near to cities and industries.

Overfishing is another major problem for the oceans. By depleting stocks of even a few species, we change the way entire ecosystems behave, often seriously. Tuna have been fished almost to extinction in the Mediterranean sea, and there is little sign that common sense will prevail to reduce the pressure on them. Tuna are predators, high up in the food chain. When you remove top predators, often the result is that a few species lower down the food-chain start to dominate, out-competing other creatures. The ecosystem becomes unbalanced, and may change its nature completely. It may not be enough to simply stop hunting the predators, the ecosystem may no longer be able to recover on its own.

Floating garbage is another serious problem. On the tiny atoll of Midway in the Pacific ocean, albatross often mistake floating plastic garbage for food, which they then feed to their chicks. That kills many of them, not surprisingly. Albatross aren’t meant to digest golf-tees, toothbrushes, and lego blocks.

Even the efforts we go to to protect the oceans and their inhabitants can often be misguided. I’m sure we’ve all heard of dolphin-safe tuna, it even got a mention in Lethal Weapon 2, released some 20 years ago. I’m fond of dolphins, like many people, but I was shocked to learn about just how much damage dolphin-safe tuna-fishing can do. The methods used to catch tuna without harming dolphins have a much higher rate of bycatch than other methods. ‘Bycatch’ is another word for ‘collateral damage’, animals accidentally killed while hunting a specific species at sea. Much of the bycatch in dolphin-safe tuna is in itself seriously endangered, far more so than dolphins themselves. No, dolphin-safe tuna is not a good thing for the marine environment.

Sunset on the Beach

Sunset on the Beach

More and more people are becoming aware of and involved in environmental issues. They are paying attention to the environmental cost of the goods they purchase, insisting on packaging that can be recycled, lower power consumption from electrical goods, or higher mileage from their cars, for example. But what can you change in your daily activities to help the oceans, especially if you live far from the sea? The Marine Conservation Society have some advice, and there’s also a page of hints at The Ocean Project. One obvious thing is to be more informed and cautious in your seafood purchases, both sites have suggestions there. If you prefer to avoid seafood altogether, simply buying organic food is a good idea. That encourages farmers to produce more of it, which means less pesticide in use. Reduced pesticide use means less of it getting into our rivers and from there into the sea, finally ending up in marine mammals like that dolphin we were trying to save a moment ago.

You can find out more about World Ocean Day at the World Ocean Network site. Maybe one of the events that they list is taking place somewhere near you. If not, there are plenty of web-based resources available, like the 24 hours in the Ocean online event from the Musée Nausicaä. I’ll certainly be following that for some of the day.

Zemanta, and the Marine Conservation Society of the UK

Sunday, May 24th, 2009
Zemanta Firefox plugin
Image by Tom Raftery via Flickr

Zemanta recently won second prize in the Change the Web Challenge for web-innovation, and they are giving away the prize money to whichever charities most people vote for. Zemanta, in case you haven’t heard of it, is a tool for suggesting content (photos and links to related articles) to add to your blog, based on whatever you’ve already typed in. It works for WordPress, Blogger, TypePad, and a wole bunch of other blogging platforms. If you’re using FireFox, you can run it as a plugin in your browser, so you don’t need to install it on your blogging host.

You can try the interactive demo on their website. Just cut and paste the text from one of your old blog posts to replace the sample text they put there, hit the ‘run demo’ button, and see what pops out. I’m willing to bet you’ll be impressed. Oh, and did I mention it’s free?

So, Zemanta, congratulations on winning that prize, and thank you for a great tool. Now on to my vote. I would like you to donate to the Marine Conservation Society UK, to help them with the work they do. The Marine Conservation Society UK is involved in a large number of activities around the British coast, and beyond. Coastline is something that Britain has lots of, so it’s an important charity!

They actively campaign to persuade the UK government to establish Marine Protected Areas, and encourage people to get involved at several levels, such as reporting sightings of basking shark, turtles, pink sea fan and many other creatures that can be seen in the seas around Britain. They encourage divers to become better observers by learning about their marine environment so they can in turn provide more accurate and useful observations to help drive conservation efforts.

Coral reefs in Papua New Guinea
Image via Wikipedia

They have a lot of educational resources for schools and project-suggestions for college students. They even organise coral reef surveys in the Maldives for recreational divers.

For the less well-heeled visitor to the British seaside, they monitor the state of beaches and publish an annual guide to the best beaches in the UK. This is not just cosmetic, many beaches pose health risks for swimmers, so knowing where to go is important. To help you get there, they even provide downloadable maps for your in-car GPS. How’s that for service!

Zemanta have had over 50 charities proposed to them so far, and will donate to the five that get the most votes. If you think that the Marine Conservation Society UK deserves a donation from them, all you need do is blog about it yourself, to add your vote.

Image representing Zemanta as depicted in Crun...
Image via CrunchBase

This blog post is part of Zemanta’s “Blogging For a Cause” campaign to raise awareness and funds for worthy causes that bloggers care about.

The Coral Reefs of the Maldives

Friday, May 1st, 2009
Anthias on the reef

Anthias on the reef

Verena Wiesbauer is a marine biologist, with particular knowledge of coral propagation and restoration techniques. In March 2009, she gave a lecture to the Maldives Science Society. Someone in the audience filmed it, and was kind enough post it on google-video, so now you can all enjoy watching “The Coral Reefs of the Maldives” as I have.

I learned a lot from this presentation, it’s very educational and entertaining. There’s a ‘pop-quiz’ early on, in which you are asked to identify what type of plant or animal is being shown. I pride myself on having correctly recognised Coriocella (though I did have to look up how to spell it), having seen them in Baa Atoll a few years ago.

Verena tells us that the Maldives sits on a volcanic chain which forms the basement of the islands. These volcanoes were active around 67 million years ago, so around the time the dinosaurs were dodging asteroids. Coral first started growing on these volcanoes some 55-57 million years ago. Since then, sea-level has changed several times, most recently after the last ice-age when it rose dramatically as the ice melted and retreated. The Maldivian atolls were flooded at that time, and the upward growth of coral only succeeded in creating islands around 3000-4000 years ago. The actual coral growth in the Maldives now forms a layer about 2000 metres thick. That’s a lot of coral!

soft coral

soft coral

Having shown us some of the animals that live in and around the Maldivian reefs, Verena goes on to tell us about some of the problems that are affecting the reefs today. Beach erosion is a serious problem. With two monsoons each year, coming from different directions, it is natural for the sand to shift from one side of an island to the other during the year. In 2000, half of the islands were sufferring from beach erosion. There are simple measures that the Maldivians can take to protect themselves from the worst effects of such erosian, such as not building too close to the shoreline and using sand and aggregates imported from India for construction (instead of dredged from their own reefs).

They can also protect the islands by protecting the living reef. A living reef will protect against beach erosion by reducing the force of the waves as they come inshore, a dead reef will soon be destroyed by the waves and offer little or no protection. A reef needs at least 50% live coral-cover to provide adequate protection, few of the Maldivian reefs have that at this time.

There are other threats to the reefs too. The Maldivians themselves generate a lot of waste, and they have nowhere to put it. The island of Thilafushi is a municipal landfill, and there is concern that all sorts of toxic waste from it may leak into the ocean and harm the environment.

gorgonian sea fan

gorgonian sea fan

Discarded fishing-lines cause a lot of damage too. One horrible slide in the presentation shows a turtle that became entangled in a fishing-line while it was young. It survived, and grew up with the fishing-line constricting its growth. I’ve never seen a turtle with an hour-glass figure before, and I hope I never do again.

Another major cause of damage to coral reefs is the tourist industry. Divers, even experienced ones, can cause a lot of damage. Verena gives a personal account of diving with tourists who lay down on the reef to watch sharks, and who were upset with her for not doing the same because she might scare the sharks away! I’ve seen divers who allowed their diving lamps to trail along the bottom of a reef like a wrecking-ball while they were concentrating on getting closer to a few manta-rays nearby.

Not surprisingly, divers with cameras cause more damage than those without, they’re focussed (literally!) on what they’re looking at, not what they’re bumping into. Diving from shore causes more damage than diving from boats, and night-diving causes more damage than diving during the day. Even without direct physical contact, reefs can be damaged by divers who kick up sediment with their fins, smothering the corals they have paid so much to see.

It’s not only divers, but also snorkellers, that damage reefs. Snorkellers will often stand on the reef to adjust their equipment, and can do a great deal of damage by careless contact. Verena cites a paper by W.R.Allison in 1996 which showed that snorkellers can can do an immense amount of damage in a short period of time.

Verena says that the dive-schools could give better briefings, for both divers and snorkellers. Her own experience is that people appreciate being reminded of the simple things they can do to reduce their personal impact. I know some dive-schools don’t like to impose on their divers, so will not mention such things in their briefings. You can always invite them to say something when they ask if there are any questions. Put your hand up and say “I have a question, do we have to be careful about what we touch on this dive?”. It’s worth a try!

Dive-schools should also respect the ‘carrying-capacity’ of dive-sites, and not visit them too frequently, so they have time to recover from each invasion. This is a particular problem in the Red Sea, where many reefs are seriously degraded by divers. Of course, that’s not easy when there are many dive-schools competing to take people to the most popular sites.

Individually, divers can take steps to reduce their impact even more. Those of you that dive with PADI can take the Peak Performance Buoyancy course (other organisations probably have something similar). You’ll find you dive better (i.e. use less air, are more relaxed) and do less harm to the reef because you have more control. You’ll see more on each dive, too, because you will spend less time fighting with your equipment and frightening fish with your thrashing, and more time looking around.

Coco-palm encourages tourists to preserve the environment

Coco-palm encourages tourists to preserve the environment

Tourism can also be a positive force. invented the slogan “When the buying stops, the killing can too“, and used it in their campaign against shark-finning. You can kill a shark for its fins only once, but if you leave it alive, tourists will pay again and again to come and see it when they dive.

Verenas’ presentation has an optimistic tone, she clearly loves her work. There are things that can be done to help the reefs, and she mentions some of the many restoration and conservation projects in the Maldives. She herself has assisted in the creation of an artificial reef at Huvafenfushi. I’ll end this post with a quotation she gave at the beginning of per presentation. It’s from Baba Dioum, a Senegalese environmentalist or poet (depending on who you ask):

In the end we will conserve only what we love, we will love only what we understand and we will understand only what we are taught

It would be good if people were taught more about the world we live in today.

“Don’t be Stupid” about climate change

Sunday, March 22nd, 2009

Mohamed Nasheed, president of the Maldives, has recently given the best political speech I have ever heard. Released with the premier of “Age of Stupid“, his message to the world about climate change was very clear. If you’ve never heard a politician talking straight and making sense before, you may find it refreshing.


Come to think of it, that makes two politicians I know of who know how to make sense, Presidents Nasheed and Obama. Hopefully it’s catching.

Pete Poslethwaite as the Archivist

“Age of Stupid” was released on March 15th in the UK. Set in 2055, it’s a film about the consequences of global warming, made using a lot of real news footage from recent times. For example, one clip features French mountain guide Fernand Pareau reflecting on the way the glaciers and Alps have changed in his 82 years. The film stars Pete Poslethwaite as a man looking back at 2008 and asking “why didn’t we stop climate change when we had the chance?”. Pete is a lovely actor, highly charismatic and gloriously ugly (no offense intended, Pete). I just loved him in “Jurassic Park – The Lost World”, a role rather at the opposite end of the ecological spectrum. Pete clearly believes in the message of “Age of Stupid”, he has a wind turbine in his garden in Shropshire.

Back to President Nasheed, what did he say in his speech? Well, for one thing, he announced that the Maldives is going to be carbon-neutral within a decade. In his own words:

The cost of this probably will be high, but please understand, failure to act will cost us the world. If the Maldives, a small, relatively poor country, can achieve a big reduction in its greenhouse gas emissions, there can be no excuse from richer nations who claim that going green is to complex, too expensive or too much bother.

That’s a bold statement, but is it really such a big deal for such a small nation to achieve that? I think so, it’s not like they have a great deal of flexibility in going carbon-neutral, their choices are very limited. They import all their wheat, so it’s unlikely they can grow biofuel crops. They can’t relocate to higher ground to escape rising sea levels, because they don’t have any high ground to go to. They have no mineral resources and very little in the way of agriculture. As far as natural resources go, they have sand, sea, coral, fish, and tourists. That’s not a lot to work with.

The credit-crunch is already affecting the Maldivian tourist trade, tourism is down 14% on last year. They are calling it the ‘financial tsunami’, referring to the drop in tourism after the tsunami of December 2004.

Global warming will damage the reefs in many ways, such as bleaching through heat-stress, acidification from the extra CO2 dissolved in the ocean, and erosion from rising sea levels and extreme weather events. When the reefs suffer, the fish suffer too, so they get hit from all sides. No, small as they are, I reckon that going carbon-neutral has to be a lot harder for them than it would be for many other nations with more resources at their disposal.

President Nasheed is taking other measures to protect his nation. I’ve written before about some of the things the Maldivian government is doing to address climate change, but that’s not all of it. He’s reduced the cost of the presidency from $150 million per year to $4 million, and is selling the $7.5 million presidential yacht. He chose not to occupy the presidential palace, it may become a museum or a university. Instead, he shares an office with his secretary. Clearly he doesn’t want to squander the resources at his disposal.

The Maldivian government also recently introduced a total ban on shark fishing within their waters, extending a previous ban which only covered the tourist atolls. Sharks are top predators in the marine environment, and as such they are essential to maintaining the health of a coral reef ecosystem. The Maldivian Ministry of Fisheries is working to find alternate livelihoods for the shark-fishermen, so they will have no reason to defy the ban. This is important when you realise that these are not rich people killing sharks for fun, but just poor people trying to feed their families, and one shark-fin can be worth $100. There’s a very good discussion on shark-finning on the Southern Fried Scientist blog, but be warned, the video linked there is not for the faint of heart.

President Nasheed says “for untold fossil fuel consumption in our lifetime, we are trading our children’s place in an earthly paradise”. It would be understandable to think that the Maldives has more at stake than the rest of us, since they are such a small, island nation, but that would be totally and terribly wrong. If the world can’t save countries such as the Maldives today, we won’t be able to save places such as London, New York, or Hong Kong tomorrow. Much of Manhattan could be under water by the end of this century, and the longer it takes for us to act, the worse it will be.

The last part of President Nasheeds’ speech is directed towards the climate conference in Copenhagen in December of this year:

Copenhagen can be one of two things. It can be an historic event where the world unites against carbon pollution, in a collective spirit of cooperation and collaboration, or Copenhagen can be a suicide pact. The choice is that stark. My message to you, my message to the world, is simply this: Please, don’t be stupid.

Well said, President Nasheed, it seems to me the world could do with more leaders like you. Perhaps if we all send a clear message to our own leaders, we might get the message through in time.

Charles Darwin’s first theory of evolution

Thursday, February 12th, 2009
Coral Island in the Maldives

Coral Island in the Maldives

Charles Darwin was born 200 years ago, on February 12th 1809. Possibly the most famous scientist ever, his fundamental and beautiful theory of evolution has stood the test of time. Darwin formed his theory as a result of his observations during the voyage of the Beagle, but it was many years from then until he actually published his ideas.

Blogging for Darwin

Blogging for Darwin

It is less well-known that, in the same voyage, Charles Darwin produced another theory of evolution, not of life but of coral reefs. The formation of coral reefs was a matter of some debate at that time, in fact, one of the mission objectives for the Beagle voyage was to study their nature. Darwin’s theory was published in his book The Structure and Distribution of Coral Reefs in May 1842, some 6 years after the Beagle came home, and 17 years ahead of his more famous work, On the Origin of Species.

Darwin’s theory of coral reef formation is all the more remarkable for having been thought out completely before he had ever seen a reef. In his own words:

“No other work of mine was begun in so deductive a spirit as this, for the whole theory was thought out on the west coast of South America, before I had seen a true coral-reef. I had therefore only to verify and extend my views by a careful examination of living reefs.”

Such a statement could imply that Darwin was biased in his views, and it would be natural to believe that he sought only such evidence as supported his theory. That this is not the case becomes apparent on reading the book. Darwin was a meticulous and thorough observer, seeking as much information as he could from a wide variety of sources. The appendix of his book, fully one third as long as the main text, contains a detailed description of a large number of coral reefs, all of which he examined in the light of his theory. The book also includes a map of the world, showing the locations of all these reefs.

Darwin accumulated such a wealth of information on reef structure and history that his theory emerges as almost an inevitable consequence. He tests his theory for its ability to explain the features of a variety of reefs and atolls, as well as the distribution of different types of reef in different parts of the world.

Island and Atolls

Island and Atolls

The theory states that, in conditions where coral can survive, it will form fringing reefs (reefs close to shore) around islands and other land masses. If that land is rising over time, the reef will grow outwards as the land rises, and the fringing reef will be stable. If the land is neither rising nor sinking, the reef will expand outwards over time, forming a barrier reef (a reef enclosing an island, at some distance from it). If the land is subsiding, the coral will grow upwards in consequence, and eventually a barrier reef, then an atoll (a more or less circular reef with no land enclosed), will be formed.

Darwins evidence was drawn from a great many sources. Using plumb-lines, he measured the depth of the sea around many reefs, at different distances from the reef. This showed him a slope too steep to be consistant with reefs being formed on volcanic craters, as was thought at the time. By using soft wax on the bottom of the lead weight, he was able to gain clues to the nature of the sea-bottom. Sand and other fragments would become embedded in the wax, hard rock would simply leave impressions in it. This helped him deduce the limits of depth at which coral can grow.

Some of his soundings were as deep as 7200 feet (2160 metres), so he was definitely doing more than just scratching the surface!

Darwin noted the importance of sediment, both in forming islands as it is washed up by the waves, and in inhibiting coral growth by smothering corals or preventing them from getting a good anchorage inside lagoons. He dissected several parrotfish to investigate their stomach contents, verifying that they do indeed eat coral, pass it through their bodies, and excrete fine sand which contributes to the sediment.

Darwin saw that the types of coral on the outer margins of a reef were different from those inside the lagoon. On the outside of the reef, larger corals grow well. Inside the lagoon, corals are less vigorous. This is largely because the outside margins have the full force of the current, bringing nutrients to the coral. Inside the lagoon, the currents are weaker, so the coral does not grow as fast. He was able to identify some of the corals in the outer margins by walking the beaches after storms and looking at the new types of coral fragments that were washed ashore.

Darwin also investigated the channels that cut through many reefs. He saw that the channels tend to form on the side away from the current. Channels facing the current would tend not to accumulate as much sediment as those on the other side, so corals could take hold and grow into the channel, closing it up over time.

Darwin was able to deduce the growth-rate of corals from many sources. He used accounts of one ship that grew a 2 foot (60 cm) thickness of coral on its hull in 20 months, as well as information about ship-anchors that had become embedded in reefs over the years, and direct observations from other naturalists.

Having been led to his theory by his intuition, and having backed it up with observation, Darwin then goes on to test his theory in many ways.

Maldivian reef

Maldivian reef

Many atolls have deep lagoons, which can be best explained by upward growth at the rim while the whole of the land subsides. If the land were rising, there is no reason for the rim to rise faster than the interior, so a deep lagoon would not be formed.

Many atolls occur in the open ocean, rising steeply from depths beyond which coral cannot grow. There is no obvious explanation that could cause such a reef to rise from the depths, but if the reef were growing upwards at the same pace as the land is sinking, these isolated reefs are to be expected.

There are smaller, irregular reefs in many places, and these too can be accounted for. As a land-mass sinks and its peaks become separated islands, linear reefs may form between them, which may persist as irregular reefs long after the land subsides.

The larger reefs of the Maldives appear to be slowly separating into smaller reefs. Darwin accounts for this by noting that particularly large atolls may be breached by wide channels. Coral can grow at the edges of these channels, and if the channel is wide enough the coral growth may eventually cut the atoll in two.

Fringing reefs occur near land that is stable or rising, but atolls and barrier reefs are formed where the land is sinking. The map shows clearly that fringing reefs tend to be apart from atolls and barrier reefs. For the same reason, volcanoes should not often be close to atolls and barrier reefs, and indeed they are not.

Darwin’s theory of reef formation and development, like his other theory of evolution, has stood the test of time. Unlike his other theory, it was well received by the scientific community and the public from the moment it was published. If it had been the only thing he published, it would still be an important work. Darwin produced many other books and papers, you can find his complete works online at I think I’ll read a few more, though the one on fossilised barnacles will not be near the top of my list. You can read more about Darwin and his work at Blog for Darwin, the site that inspired this post.

Happy birthday, Charles Darwin.


Sunday, January 4th, 2009

Climate-change and global-warming are among the main themes for this blog, and that is one subject certain to encourage the pessimism in a person. On the face of it, if you accept the scientific evidence for global warming and the rate at which climate-change is happening, it can seem hopeless to attempt do anything about it. Individual actions are just so small on the scale of the problem we all face, and actions of nations on the other side of the world can make everything you do seem irrelevant. Coral reefs are sufferring, the Arctic ice is disappearing fast, extreme weather events are on the increase, and major governments are waiting for someone else to take the first step. The world’s climate has already been changed by mankind, and further change is inevitable, no matter what we do next. Why bother to try to recycle, to save petrol or polar bears, or do anything at all when faced with such a challenge?


Despite this, I personally am optimistic about the future. It’s true that we face a challenge of immense proportions, but individual actions really can make a difference. We talk about “saving the planet”, but the planet is not in peril. It is us, our children, and the plants and animals we share this planet with which need saving. Solving the problem of climate-change means nothing if it is not about saving those lives, those species. The problems of climate-change and conservation of wildlife are closely related. Action is needed by governments, yes, but also by individuals. Governments won’t be able to solve this problem if we don’t want them to. Every level of society needs to be involved, from the UN down to you and me. We don’t need someone else to go first before we act, we can all start now and do something in our own corner. The more people act, the sooner they act, the more difference it makes.

Here are some of the things that happened last year that give me cause to be optimistic.

In Britain, the Royal Society for the Protection of Birds ran a campaign in 2008 asking people to do something in their gardens to help birds and the insects they depend upon. Some 25,000 homes responded, with all sorts of contributions. Even something as simple as choosing the right plants for your balcony can make a difference to your local birds by encouraging the right sorts of insects at difficult times.


In September last year, the European Parliament published the results of a survey of 30,000 people around europe to find out their attitudes to climate-change. It seems that 3 people out of every 5 have already taken some personal measure to reduce their carbon footprint. So the majority of europeans have already done something on their own, without waiting for their governments!

Interestingly, 1 person in 10 said that they did not know what they could do to reduce their carbon footprint. Simply talking to people and spreading information is therefore an important thing to do.

Another survey, this time by the BBC, asked 22,000 people worldwide what they know and think about the problems of climate-change. 9 out of every 10 people asked think something should be done, with 2 out of every 3 saying that drastic action is needed in the near future. Even the majority of the Chinese people (7 out of every 10) think that serious action is needed soon. The same picture emerged in almost all the nations included in the survey. Clearly, people accept the need to act when they are well informed.

Trees in Spring
Trees in Spring

On a different scale, the European Parliament recently introduced tougher controls on pesticides, such as banning arial spraying, protecting water-resources with buffer-zones, requiring the use of safer alternatives where they are available, and reducing pesticide use in parks, playgrounds, and other public areas.

Perhaps the most optimistic event of 2008 in this respect has to come from the United States. President-elect Obama has chosen real scientists to take key posts in his administration, including a Nobel laureate. Maybe now more governments will stop looking at each other and start looking at themselves.

None of these things is going to “save the planet” on their own, but each of them together may mean that there will be more of the planet left tomorrow, and the day after. Simply knowing that people do care to act once they know the truth is, to me, very encouraging. It’s a beautiful world, and it always will be. Just how beautiful is up to us.

I wish you a happy and peaceful new year.

Snow on Logs
Snow on Logs

The Maldives

Thursday, December 4th, 2008
Mirihi island, Ari atoll, the Maldives
Mirihi island, Ari atoll, the Maldives

This is Mirihi Island, in the Maldives. It’s a small island in Ari atoll. The Maldives are a chain of coral islands in the Indian Ocean, near the southern tip of India.

I’ve been to the Maldives a few times, and I learned to dive there. Having watched Jacques Cousteau bubbling his way across the screen as a kid, I actually got to do some of it myself.

Sharks at Anga Faru
Sharks at Anga Faru

I went from beginner to PADI divemaster in one year, got myself an underwater housing for my digital camera, and went for it. You can see some of the results here, the sharks at Anga Faru in Baa Atoll, a Giant Moray with a cleaner shrimp, and a nudibranch (Tambja Olivaria).

The Maldives are well-known for many reasons. The word atoll comes from Divehi, the native language. Its use in English was popularised by none other than Charles Darwin, whose theories of reef-formation are one of the lesser-known results of his travels.

Another claim to fame for the Maldives, until recently, was that they had the longest-serving leader in Asia. Maumoon Abdul Gayoom held power for 30 years. He was succeeded recently in democratic elections by Mohamed Nasheed.

Giant Moray with cleaner shrimp
Moray with shrimp

Perhaps they are most famous as a holiday destination, but they also hit the headlines as one of the many nations to fall victim of the tsunami of December 26th 2004.

A more worrying claim to fame is that they are one of the island nations that is almost certainly doomed to disappear in the coming century as a result of global warming. The sea-level in the Maldives is projected to rise 50cm or more, by the end of the 21st century. Given that the Maldives is little more than one or two metres above sea-level at best, this is already a lot. But the Maldives will run into trouble long before the sea actually covers it completely.

The Intergovernmental Panel on Climate Change discusses island nations explicitly in its fourth assessment report. It has a few predictions common to all such small island nations in the report of Working Group II (“Impacts, Adaptation and Vulnerability“).

Tambja Olivaria, a nudibranch
Tambja Olivaria

Flooding, from storms, will intensify. Coastal erosion will accelerate. Coral reefs and fisheries will be affected, and fresh water will become scarce. Agriculture and infrastructure will suffer as a result. Even the tourist industry, a major part of the Maldivian economy, is expected to suffer significantly as the Maldives become less attractive to tourists. These are all predictions of which the IPCC is “highly confident”.

The Maldivian government is not ignorant of these threats, and the IPCC note that their Ministry of Home Affairs has considered ways to help them address the matter. Chapter 16 of Working Group II has a list.

  • Population consolidation i.e., reduction in number of inhabited islands
  • Ban on coral mining
  • Protection of international airport, upgrading existing airports
  • Increase elevation in the future
  • Reduction of human impacts on coral reefs
  • Assigning protection status for more reefs
  • Coastal protection of resort islands
  • Reduce dependency on diving as a primary resort focus
  • Economy diversification
  • Explore alternate methods of growing fruits, vegetables and other foods
  • Crop production using hydroponic systems
  • Protection of groundwater
  • Increasing rainwater harvesting and storage capacity
  • Use of solar distillation
  • Management of storm water
  • Allocation of groundwater recharge areas in the islands
  • Human resource development
  • Institutional strengthening
  • Research and systematic observation
  • Public awareness and education

That’s not enough for the new Maldivian President, who is under no illusions about the future of his country. He clearly realises that all the Maldivians can do where they are will only buy them a little time. So, as the BBC reported recently, he is actually planning to buy a new homeland for the Maldivian people.

The photo at the top of this article was taken 4 days after the tsunami of 2004. Mirihi escaped practically unscathed on that occasion, but its future does not look good. Within my lifetime, this island, and much of the Maldives, could well be gone.