UNKNOWN WORLDS
IT’S NOT ONLY NEW SPECIES THAT ARE WAITING TO BE FOUND – THE DISCOVERY OF WHOLE ECOSYSTEMS, FROM THE SEA FLOOR TO RAINFORESTS, CONTINUES TO CONFOUND SCIENTISTS, REPORTS JOHN VIDAL.
The text books are unanimous. Coral reefs don’t form at the mouths of the world’s major rivers because the huge quantity of mud and sediment washed out to sea by a river’s plume blocks sunlight and prevents photosynthesis. No light means no corals.
But Brazilian marine ecologist Fabiano Thompson had his doubts. Fishermen reportedly dragged up corals and sponges near the mouth of the Amazon, and fish and lobsters normally associated with reefs were also sometimes found there. Something strange was going on.
Between 2012 and 2014, Thompson and other scientists got their chance to find out more. Joining US research vessels, they took water samples and measured the light and oxygen levels at different depths of the murky waters 96–160km off the coast of Brazil.
Thompson was surprised to find carbonates in the sediment, indicating the presence ce of corals, plus red algae ae known as rhodoliths and sponges. But at first, rst, the implications of these ese findings led the scientists tists to suspect their measurements were incorrect.
It was only when Thompson hompson returned home and wasas going over the data that he truly ruly understood its significance. cance.
“My moment of astonishment onishment came when I realised that the
chemical profile of water in the plume of the river was different to the non-plume areas,” he said. It suggested that a reef was being formed by the algae carried in the river sediment.
CORAL BREAKTHROUGH
After this, Thompson and 38 other oceanographers, biologists and marine scientists from 12 Brazilian institutions made further expeditions to dredge and measure small areas of the seabed. Last May, they finally published a major scientific paper announcing the discovery of a massive coral reef at the mouth of the Amazon.
It was, they said, 1,000km long and covered nearly 9,500km2 – that’s about half the size of Wales – at depths of 30–120m. They thought it was relatively “impoverished” compared to other coral reefs but even so, they reported 60 species of sponge and 73 species of fish, plus spiny lobsters, starfish and many other types of marine wildlife commonly associated with coral reefs.
In February this year, Thompson and three other scientists returned, this time with Greenpeace, which had hired a two-man submarine, for them to observe the reef for the first time. Within a few dives, he knew that they had greatly underestimated its importance.
The submarine revealed a huge, pristine reef, covered in life. “It was far richer, deeper and more important than we ever imagined,” he said.
Many aspects of its geological, chemical and biological composition are unique, Thompson added. “In the first three dives we found three new species of fish and dozens of others we never knew lived in this area. It’s as important for life as the Great Barrier Reef and we have only explored a tiny bit of it.”
His colleague Ronaldo Filho, a marine ecologist from Paraíba University, was equally astonished. “There could be many new life forms down there,” he said. “The discovery is beyond amazing – we are rewriting the textbooks.”
The discovery of the reef has excited oceanographers, ecologists and a public hungry for positive news about the environment, especially coral reefs which are suffering the effects of climate change and pollution. Deep reefs such as this may be less susceptible to negative impacts than shallowwater ones, Filho said, and could act as refuges for some species.
Nick Polunin, professor of marine ecology at Newcastle University, applauded the Brazilian researchers, but said he was not altogether surprised.
THE NEW CORAL REEF IS NEARLY 1,000KM LONG AND COVERS SOME 9,500KM2.”
73 The number of fish species discovered on the new Amazon coral reef. IN 2008, THE LARGEST TRACT OF MID-ALTITUDE RAINFOREST IN SOUTHERN AFRICA WAS DISCOVERED.
“Nearly all ocean research has been done in the top 20m of water by diving,” he said. “Divers can’t easily go beyond 100m for safety reasons, so the deep sea floor is a huge unknown. We know less than one per cent of what goes on down there.”
MYSTERIES OF MOZAMBIQUE
Even on land, scientists can still discover new ecosystems. British conservationist-explorer Julian Bayliss was on a Kew Gardens expedition to the Mount Mulanje massif in southern Malawi in 2005 when he observed a range of similarlooking granite hills in the distance towards Mozambique.
“I wondered how similar they were to Mulanje,” Bayliss said. “There was no information about them, so I turned to Google Earth and identified six mountains over 1,500m high. Then I went on a recce.”
Bayliss found old abandoned tea estates around Mount Mabu, but very few people living there because Mozambique was still emerging from a long civil war. Around the bottom of the mountain, he could see a vast expanse of forest that had never been mapped.
He returned in 2008 with an expedition and discovered the largest and most intact tract of mid-altitude rainforest known to exist in southern Africa. This biodiversity hotspot had never been mapped before and yet it covered nearly 80km2. The expedition found many new species of snakes, butterflies, crabs and plants, many of which are still to be described, as well as a new pygmy chameleon.
“There is so much more to find,” Bayliss said. “People assume that we have discovered most things and most places, but there are very many remote areas where no one has been.”
Indeed, taxonomists suggest there could be more than eight million species on Earth, but science has discovered fewer than two million, which means that three quarters of all species have yet to be found and named.
More recently, Bayliss has identified, again in Mozambique and using Google Earth, an ancient volcano with thick forest in its crater. Because its granite sides are smooth he says it is quite possible that it will be another lost world – possibly with unique species – where no human has ever set foot.
TABLETOP TEASERS
Other known ‘unknown worlds’ include the tepuis or tabletop mountains of Venezuela and especially their cave systems, where researchers have discovered endemic life forms such as blind cave fish.
In 2006, the discovery was reported of a new species of poison-dart frog in a tepui cave so huge that an expedition was able to land helicopters in it. Incredibly, the Cueva de Fantasma or Cave of the Ghost had never been photographed before. But scientists know they have only scratched the surface of these remote environments.
Exploration is the lifeblood of science and the Brazilian scientists who discovered the Amazon reef, Bayliss who found a rainforest, and dozens of other oceanographers, biologists and ecologists will continue to explore the deepest, remotest and least known places on Earth.
“Who knows what else is out there?” said Ronaldo Filho. “All we do know is that there are plenty new life forms and places left to discover.”