Science's last frontier lies just beneath our feet

Posted: 16 December 2002

Author: Tim Radford

Scientists have launched a systematic study of the last great unexplored territory of the globe: the few inches of soil beneath our feet.

Researchers in seven countries have begun a five-year, $26m (£16.8m) discovery of the tiny, unknown plants and animals that make the rest of the world work.

Tiny creatures - microbes, worms, fungi, beetles and mites - turn the soil, break down dead wood and leaves, fix nitrogen from the air, produce fresh nutrients for crops, manage the water cycle, release carbon dioxide, methane and other greenhouse gases and underpin all life above ground.

Forests, savannahs and farmland are all supported by a huge and largely unknown suite of creatures living in the first metre of soil below the surface. They have yielded some of the world's most important antibiotics, and have saved farmers billions of pounds in fertilisers and pesticides.

They could launch a new agricultural revolution and yield untold riches for the industries of the future. They are the least studied organisms on the planet.

"When people think of where new species might be found, they tend to think of rainforests, mangrove swamps, or places like mountain peaks - not millimetres below their toes," said Klaus Toepfer, the director of the UN environment programme.

The nations in the UN-backed programme are Ivory Coast, Uganda, Kenya, Indonesia, India, Brazil and Mexico. Research will begin in the tropics, because these regions are the least studied.

Thin skin

Jo Anderson, of Exeter University and the chairman of the programme's advisory group, said: "We have this image of this incredibly fragile, and critically important skin across the earth which is maintaining just about everything we are familiar with. It is vital to life as we know it. But we are simply unaware of the diversity of organisms supporting that."

There was probably greater biological diversity in a handful of soil from a garden in Devon than there were plants and animals in the tropical rainforest. A piece of soil the size of a sugar lump might hold five metres of fungal filaments of the kind usually visible on mouldy bread.

"We are dealing with incredible numbers," he said. "Some of these woodlands, up to almost a kilometre square, have got one genetic individual of a fungus which is probably thousands of years old and collectively weighs more than the largest dinosaur, or a blue whale. A tonne of soil could contain millions of varieties of bacteria. Only 4,000 have been named. The 72,000 species of fungi known so far represent only about 5 per cent of the possible total."

Researchers have identified 15,000 nematode worms: there could be 100,000 species. There are probably twice as many earthworms as the 3,600 so far studied.

Streptomycin and penicillin were both made by soil-dwelling bacteria. Chemical industries and pharmaceutical giants have launched massive programmes to screen soil organisms for unusual and useful properties. But the biggest rewards may lie in managing soil organisms to save on pesticides and fertiliser use. Releases of native earthworms in tea plantations in India boosted productivity almost threefold and raised profits by $5,500 (£3,500) a hectare each year.

The right strains of nitrogen-fixing bacteria sprinkled on soybean plantations in Brazil had replaced artificial fertilisers and were now saving the national economy $1bn a year.

Researchers will also work with farmers and indigenous peoples in each country to make the best of local knowledge. They will also look at ants and termites. These play a huge role in enriching tropical soils. Termites also provide health supplements as they spread new soil from deep underground over fresh leaf litter and animal dung.

"That is immensely fertile," Professor Anderson said. "In some areas of Africa, the women when they are pregnant have a tradition of eating this termite soil. Analysis shows it is very rich in available iron and zinc. It is like a vitamin tablet."

Tim Radford is Science Editor for The Guardian.logoThis article was first published in The Guardian, (Friday November 29, 2002). All rights reserved. Reproduced with kind permission.