For many scientists, there are only two types of material: living and dead. "It makes thinking nice and easy," says Paul Kench, a geologist with the University of Auckland in New Zealand.
Islands, for example, are generally assigned to the sphere of the inanimate. Kench, however, wants to convince the scientific world that the opposite is true. That's why he is currently spending much of his time swimming around with flippers in the emerald-green waters of the Indian Ocean.
Kench traveled to the Maldives with five fellow scientists. Together, they intend to fathom the true essence of the tropical archipelago. "These islands are like a growing organism, constantly changing and sometimes even ceasing to exist," says Kench.
The New Zealand scientist has studded this unusual body of islands with sensors to measure its growth. The other team members want to see how he does it, and so, equipped with masks and snorkels, they dive into the amazing underwater world of the islands' lagoons. Flat, rounded shapes with jagged edges and odd-looking spheres become visible. They see a forest of coral, whose chalky skeletons form the reefs. The islands owe their existence to the life-and-death cycle of these marine organisms.
A tube about as long as a forearm comes into sight in the midst of this bizarre underwater landscape, wedged between two table corals. Kench gives the thumbs-up signal and the other divers nod. The tube is one of the sediment traps they have set up. They are designed to collect limestone particles from dead corals, the grains that form the foundation for the magnificent beaches of this tropical paradise.
The volume of captured sediments reveals how much new sand is coming from the corals, material that contributes to the growth of the islands. "By taking these readings," Kench explains after surfacing from the dive, still a little out of breath, "we hope to come up with as precise an assessment as possible."
The solution to this question is of more than just academic interest. Like many other atoll islands, the Maldives are considered an endangered paradise, as global warming causes sea levels to rise. According to the grim scenario many scientists envision, the archipelagos, unprotected against the tides, are doomed.
"But this concept is much too simple," says Kench. He is, of course, aware of the explosive nature of such a statement.
Symbols of Climate Change
Like polar bears on their melting ice floes, the sinking island paradises have become symbols of climate change. In a calculated effort to draw attention to the plight of his country, Maldives President Mohamed Nasheed held an underwater cabinet meeting at the end of last year, just before the United Nations Climate Change Conference in Copenhagen. "If we want to save the world, saving the Maldives, I suggest, is a very good starting point," Nasheed said.
In this heated climate, Kench and his fellow scientists warn against drawing premature conclusions. Only last month, Kench and Arthur Webb of the Fuji-based Pacific Island Applied Geoscience Commission published a study whose results were completely unexpected.
The geomorphologists compared old aerial photographs taken in World War II with current satellite images. To their surprise, they found that most of the atolls they were studying had either grown or remained unchanged in the last few decades, even though the sea level has already risen by 12 centimeters (about 5 inches).
As soon as it was published, the study became ammunition in the political battle over global warming. Climate activists questioned its conclusions, which would normally be welcomed as good news. Skeptics of anthropogenic climate change, on the other hand, seized upon the study as evidence that all the excitement over global warming is completely unnecessary.
Time to Scrap the Model
Scientists find this polarization distressing. "We take climate change very seriously," says Kench. "But in order to correctly predict the real consequences for the atolls, we first have to understand how they will actually respond to rising sea levels in the future."
So far, research into the consequences of climate change has drawn on a relatively simplistic model, according to which the islands should have been shrinking for some time. Despite its weaknesses, the model is still used today, and it even played a role in studies for a report by the United Nations Intergovernmental Panel on Climate Change (IPCC). Kench and his fellow scientists, who refer to their atoll research group as REEForm, believe it is high time to scrap the model.
Considering the size of the public interest in the topic, we know surprisingly little about the dynamics of coral islands. Geomorphologists like Kench, who are familiar with the growth processes of atolls, are a rarity. Indeed, half of the world's experts in the field are part of his small team conducting research in the Maldives.
'Storms Are the Real Architects of the Islands'
The only local resident in the expedition is Ibrahim Naeem, director of the Maldives' environmental protection agency. The 38-year-old scientist is playing tour guide for the scientists as they explore the coral islands. Their first stop is an island that's about the size of a football field, with a name -- Bodukaashihuraa -- that no one on the boat can pronounce. The uninhabited speck of land is home to three palm trees.
The scientists are welcomed by swarms of mosquitoes but, caught up in the excitement of their work, they hardly even notice. They are more interested in determining whether it makes sense to drill into the reef to take a sediment sample. Together with Scott Smithers, an Australian geologist, Kench gets to work.
The two scientists have already drilled quite a few holes into the atoll. By studying the samples, they were able to determine that the Maldives attained their current form about 4,000 to 5,000 years ago.
The corals to which the islands owe their existence colonize underwater mountaintops, the remnants of sunken volcanoes. Their limestone skeletons are the building material of atolls. In the Maldives, they form a reef around the sunken volcanoes, which continues to grow until it rises above sea level in some spots. Waves and currents grind up the dead corals and deposit the sediment, which eventually accumulates to form beaches and islands.
Kench, who, with his athletic physique, looks more like a surfer than a professor, grabs a shovel and plunges it into the loose sand directly above the beach. The roots of a young banyan tree permeate the soil. All it takes is a few cuts with the spade to reveal the structure of the island, which consists of alternating layers of gray and yellow material, resembling a sandwich. After digging about a meter into the soil, Kench has already exposed half a dozen of these layers.
He explains that the gray layers are the remains of weathered plants, while the yellow layers are coral sand that periodically washes across the island after heavy storms. "Storms are the real architects of the islands," says Kench. Even natural disasters like the 2004 tsunami, which killed at least 82 people in the Maldives, do not destroy the islands. On the contrary, the Indian Ocean tsunami even added new sediments. "We've measured up to 30 centimeters of growth in some places," he says.
In earlier epochs, the islands also proved to be extremely hardy. For example, when the glaciers melted after the last ice age, the Maldives held their ground against the resulting rise in sea level -- thanks to the constantly growing corals. Based on their sediment samples, the scientists conclude that, around 2,000 years ago, the water level must have been even higher than it is today. "Constant change is the real constant in the life of coral reefs," says Smithers.
But will the islands also survive the future rise in sea level, which is likely to occur more rapidly than in the past? As global warming continues, the sea level could rise by more than half a centimeter a year. According to the IPCC, the world's oceans could rise to levels more than half a meter higher than at the beginning of industrialization.
The reseachers theorize that rising tides will flush the sediment to higher and higher elevations behind the beach. Their biggest concern is the interior of the islands, which the coral sands are not as likely to reach. If the center of an island grows more slowly than the perimeter, its elevation will be lower and lower relative to the rising sea level. And if people live in this area, their houses will likely be flooded by spring tides with growing frequency. Dumping more sand into the central parts of the islands could avert this problem, however.
Adapting to Warmer Temperatures
Biologist Bernhard Riegl, 49, of the National Coral Reef Institute in Florida has just returned from a dive, where he inspected the coral reef. "Everything depends on how well the corals continue to grow in the future," says Riegl, who is originally from Austria. As the concentration of CO2 in the earth's atmosphere rises, so does the acid content of the oceans -- and acid dissolves the limestone skeletons of the corals.
Extreme heat is also stressful to many corals. "They are extremely well-adapted to their environment here, and they'll bleach out if the water temperature rises by only one or two degrees," Riegl warns. The year 1998, for example, was particularly warm, with temperatures in the Indian Ocean higher than normal. "In the end, the corals in many reefs were completely destroyed," says the biologist. If water temperatures continue to rise as a result of climate change, things could become dicey for the corals.
On the other hand, corals are also relatively adaptable. "I saw a coral species down there that's also found in the Persian Gulf," says Riegl. There, he explains, the species has adapted to the warmer temperatures. "It tolerates water that's 10 degrees warmer than the water here."
The Importance of Excrement
Riegl made another interesting observation during his dive. He saw large numbers of parrotfish swimming in the coral garden. Scientists now know how important a role the fish play in the development of the tropical islands.
"They gnaw at the algae on the coral, and in doing so they always remove a small amount of limestone from the surface," Riegl explains. The fish digest the material and excrete the limestone, which is then flushed onto the beaches by waves. "Their excrements help the islands grow," says Riegl.
But parrotfish often end up in fishing nets. "The people here control much of their future," says Riegl.
The Sins of Civilization
Why this is the case becomes clear to the scientists when they explore another island. There are 600 people living on the tiny speck of land. Most are fishermen, and all are devout Muslims. When the scientists arrive, the inhabitants, wearing white caps, are hurrying to the mosque at the center of the island. The muezzin is calling the faithful to Friday prayers.
The scientists, meanwhile, are investigating the sins of civilization. "What kind of sea grass is this?" Kench asks the local environmental official, who smiles and shrugs his shoulders. The proliferating grass makes for an idyllic scene, its blades swaying back and forth with the motion of the waves. But the scientists know better. They speculate that nutrient-rich sewage is what makes the grass grow so rampantly. "It's an excellent fertilizer, ideal for the plants but bad for the atoll," says Webb.
Webb gives a brief open-air lecture on coastline management. "The sea grass intercepts the sand as it's flushed in from the coral reef," he says. As a result, the coral sand doesn't reach the beach, where it's needed to stabilize the island. "To protect the Maldives," Kench adds, "people have to refrain from doing all the things that hamper the natural growth of the islands."
'The Wheel of Time Can't Be Turned Back'
Breakwaters and quay walls, especially when they are too long, are detrimental because they block the path of the coral sand. Modern civilization, with its concrete buildings that are displacing traditional wooden huts on more and more islands in the Indian Ocean and Pacific, is not very compatible with the varied character of the islands. Resort hotels are also a problem. "But the wheel of time can't be turned back again," says Kench. For this reason, he suggests that protecting the beach shouldn't be the top priority. In the best-case scenario, the beach should continue to grow with the tides anyway.
"It would make more sense to build up the lower-lying interiors of the islands," says Kench. Those who insist on building there, he adds, should build their houses on stilts, "so that everything isn't destroyed when the island becomes flooded in a storm."
Naeem, the environmental official, listens impassively. He knows that the Maldives government has already taken other, more rigorous steps to secure the islands' future.
Plenty of Space
A speedboat takes the scientists to Hulhumalé, an island with an angular shape that has little in common with the shapes created by nature in the Indian Ocean. As they approach the island, they notice its steel sheet pile walls, which have a concrete crown. "Welcome to an artificial island," Naeem says proudly.
The scientists board a bus that takes them along wide asphalt streets, but there are no cars yet, only four-story apartment buildings painted in orange and green. All the buildings are neatly numbered, a suburban landscape with freshly planted palm trees.
The government intends to resettle families from the overpopulated main island, Malé, on Hulhumalé. But Naeem also anticipates an onslaught of new residents from remote atolls, of people who will succumb to the temptations of cooking in tiled kitchens and riding around on mopeds.
Of course, he adds, there will be plenty of space for all those whose land is in fact sinking. The island, created by engineers, can also grow -- not with the help of corals, but with cranes.
"If the water rises up to our necks," says Naeem, "we'll just raise the pile walls again."