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Biologist Mike Dilger leads a thrilling tour of the subterranean world.
Monday 9.00-9.30pm 1 December, 2003

The series begins with a most unusual soil safari. Using sophisticated audio techniques, the microscopic world is magnified so that the presenter, Mike Dilger, can travel through the leaf litter and down between the air spaces of the soil to meet the underground inhabitants.

mole, worm, Mike, hedgehog
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Programme 1 Soil Safari

Its an astonishing thought, when you think about it, that more than half of all life on earth is beneath our feet and what’s more, that without it, we simply couldn’t survive. Beneath our feet are the recyclers and decomposers essential for the sustainability of life itself.

By the power of radio,  listeners are able to join Mike as he journeys down through the soil profile. To help him on his way, he catches a ride on an earthworm, watches in amazement as water-bears re-hydrate before him, and spring-tails leap about around him. He slips past a nematode, avoids being engulfed a fungal hyphae, excavated by a mole and eaten by a hedgehog. Through these encounters with the underground workers, he uncovers a world of recycling and decomposition crucial to supporting life above ground.

Within just handful of garden soil, there are more creatures than there are humans on the entire planet.” (David Wolfe, Professor of Ecology at Cornell University, and author of "Tales from the Underground").

There are about 5 million amoebae (single celled animals) in every teaspoon of soil “ (Liz Stockdale, Rothamsted Research)

“… in a square metre of soil, 50-100,000 individual springtails” (Steve Hopkins, Reading University)

Its likely that every grain of soil (certainly topsoil) has passed through the body of an earthworm … from 2 to 250 tonnes per hectare per year pass through the guts of earthworms “ (Kevin Butt, University of Central Lancashire)

As Mike's journey proceeds, a series of “talking heads” are heard. These are the voices of microbiologists, naturalists and soil ecologists who guide Mike through the soil environment describing the inhabitants, their adaptations to their underground lifestyle, and their various roles in the recycling (of carbon, nitrogen and oxygen what’s waste for us is food for them) and decomposition industries below ground, which are essential to life above ground.

Of course, travelling underground can be a treacherous business, and Mike has to watch out for moles as they tunnel through the soil. Moles are supremely well adapted for their underground life, even to the extent that their blood is adapted to take up oxygen at the very low levels in the soil environment; rather like llamas at high altitudes in the Andes!

Of course, moles aren’t the only danger: in the leaf litter and upper soil layer, hedgehogs can be a serious threat to earthworms and beetles etc. Hedgehogs have an incredibly good sense of smell, which helps them track down their prey.

And then deep down in the soil, there’s another insidious killer; a predatory fungus called Arthrobotrys armed with inflatable lassos, which can be released when touched. They capture and strangle their prey before digesting it.

En route, Mike also discovers how some fungi form a relationship with plant roots which benefits not only the fungi but the plants as well, and he discovers why a "knobbly" legume root, can be a healthy sign of life and how the entire nitrogen fixation of the planet, one of the key cycles of life, is down to just 5-10lbs of nitrogenase enzyme “its kinda spooky” points our ecologist, David Wolfe!

Sources of Further Information

Tales from the Underground: A Natural History of Subterranean Life by David W. Wolfe,
published by Perseus Publishing, Cambridge, Massachusetts, 2001
ISBN 0-7382-0128-6

Hedgehogs, by Nigel Reeve,
T & A D Poyser Ltd. London,
ISBN 0-85661-081-X,

The Formation of Vegetable Mould, Through the Action of Worms, With Observations on Their Habits by Charles Darwin, 1881

For University and Institute websites for further information relating to the work of other contributors see below

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