LONDON: The Mascarene plateau is below the Indian ocean, but you can see it from space. For the past three years, scientists, divers, yachtsmen, fishermen, local children — and even Prince William on his gap year — have been drafted in to explore the mysteries of the Mascarene plateau in the Shoals of Capricorn project. Led by the UK’s Royal Geographical Society and the Royal Society, the project’s findings will be presented next week — but these waters still run deep.

The Royal Geographical Society periodically drops in on some part of the planet and takes it to pieces to see how it works. Having taken close looks at the deserts of Oman, Africa, the rainforest and so on, the expedition researchers decided on an ocean “choke point” where waters are squeezed and interesting things happen.They might have chosen the straits of Gibraltar, or the Yemen-Red Sea region.

But they opted for the Mascarene plateau which runs 2,000 kms from the Seychelles in the north to Mauritius and the islands of Rodrigues and Reunion in the south. The landscape that now reaches 3,000 metres up from the sea bed, staying 50 metres below the surface bar a few scattered islands, once formed an archipelago of islands the size of the Isle of Wight, or Jersey and Guernsey. This dry land once supported plants and animals — and possibly even humans.

“There are people who think human beings might have got there,” says Nic Flemming of the Southampton Oceanography Centre, and a researcher on the Shoals project. “All the fossil indicators of landscape and shoreline have been found and we expect to find much more. The terrain, the soil, probably the pollen, the seeds which will tell us about vegetation, mangroves; All that will be found, together with snails, small beach shells, possibly fossils of insects and so on, in anoxic muds and mangrove roots. What the landscape would have been like and what would have lived on it should become clear.”

The waters above the Mascarene plateau are rich in life. Biologists conferring in Rodrigues identified 1,000 species from nine big grouping. They identified 177 fish species, 175 gastropods, 150 kinds of algae, 106 bivalves and 104 species of coral, as well as crinoids, starfish, amphipods, and so on. The riddle, once again, is where the nutrients for such richness comes from.

Tom Spencer, science director and a geographer at Cambridge University, thinks the food source may lie in the rich beds of seagrass on the banks. Or it may be shipped in from the vast deep. The south equatorial current has to cross the Mascarene plateau, and although ocean surface waters are nutrient-poor, the depths are another kettle of fish.

“So what happens to that water, as it moves across? It has got to get over that structure. It gets squeezed, some through the passages in the ridge, and some of it presumably gets pushed up over the top, so it must be accelerated,” he says. “The surface oceans are areas of very low productivity — people talk of ocean deserts — but there is very nutrient rich, carbon dioxide rich, cold deep water underneath. So potentially these areas are highly productive. Knowing more about the patterns of productivity and how they change over time and space is extremely important.”

There are more puzzles. One is why the plateau is there at all. Another is why it remains submerged. Huge structures such as the Great Barrier Reef, off the coast of Australia, would also have been drowned when sea levels rose at the end of the ice age. Nevertheless, the reefs of living coral managed to keep up with sea level rise, or at least catch up later. The Seychelles in the north are bits of granitic material left behind by the Indian landmass as it crept across the planet’s surface after the break up of Gondwanaland. The islands of Reunion and Mauritius in the south are volcanic. In between are the shallow limestone banks and shoals which were once coral reefs.

“When sea level rose again, 10,000 years ago, why didn’t these systems switch, and either keep pace with sea level change or catch up with sea level when it slowed down 6,000 years ago?” Dr Spencer asks. He thinks it may have a lot to do with ocean temperatures. Corals tend to live near the top of their range of tolerance (and experts have been predicting that global warming could kill off most of the world’s coral reefs.) Between 1997 and 1998, as the Shoals of Capricorn project began, there was a powerful El Nino event, heating up the oceans. The researchers got a chance to see, at first hand, just what such a blister of ocean heat could achieve.

“There was very severe coral bleaching in parts of this region. In the Seychelles, 80 per cent or more of the corals were killed in this warming of the waters,” he says. “But we know from the geological record and elsewhere that there were El Nino events in the ice ages. My pet theory is that perhaps there was some kind of warm water event which knocked the corals out long enough for the sea level to rise.” The research bases launched by the project, and the data they gathered, will now go to local institutions, but the scientists reckon the study should continue.

“Any good research programme throws up as many questions as it answers. I think we have just started, really,” says Dr Spencer. “When you were young and you wanted to learn about the oceans you worked your way to the back of the atlas, and there was a fixed map of what the ocean currents were, what ocean temperature was. But those are long-term averages. What we are starting to learn about now is what one might call ocean weather. We can actually see systems in the oceans, in the way we might see atmospheric systems, and that gives us this enormously new dynamic view.”

Nic Flemming, agrees. Geographers have in effect begun to resurrect an Atlantis-type landscape, a drowned testament to a vanished world.

“We have opened the box,” he says. “It is not a can of worms, it is much more fun than that. We picked an area which we thought would be extraordinary. At the end of three years, we know that it really is extraordinary.” —Dawn/The Guardian News Service.