Monday, January 21, 2008

The Earth Moved by Amy Stewart

On the Remarkable Achievements of Earthworms

Nearly thirty years ago in Long Beach, across the street from the office building where I worked was a gooey black-caked field where once had been stored oil-field equipment, used pipes and barrels, all dripping with remnants of oil and refinery waste. One day, there was this barren plain stretching eight square blocks; the next there were mounds of soil curtained with poly sheets to prevent runoff trenching. It was part of an experiment to see how soil remidiation could be performed with one simple ingredient: earthworms.

Today, there are new offices, houses, cafes and shops on that ground. The earthworms accomplished it all. No measurable trace of toxins or hydrocarbons remains, other that what would be expected in rich soil. I thought a lot about that transformation as I read Amy Stewart's The Earth Moved, a paean to the accomplishments of the lowly earthworm.

An organic gardener, Stewart describes the worms she keeps in a composting bin beside her back door as an opener to this journey through the lives and doings of worms. She has brilliant company on the way: Charles Darwin, who spent the last years of his life studying the way worms produce compost, Thoreau and e.e. cummings and even Friedrich Nietzsche. But it is the worms who have center stage, from the giant Oregon worm (which may be extinct — we simply can't dig fast enough to find out) to the microscopic nematode.

Stewart's passion for the topic is evident as she details the ways, beneficial and not, in which earthworms affect our planet. For example, the toxic remediation I witnessed in Long Beach is one of the promising accomplishments of worms. In digesting organic matter in the soil, worms can balance methane outgassing, eliminate toxins by combining them into less-harmful substances, and erect a chemical barrier against certain kinds of garden pests. They also encourage the growth of molds and the mycelia of fungi, which help the roots of plants take up nutrients from the coil.

On the other hand, non-native worms released in some areas can do great harm: the native hardwood forests in the Northeastern US, for example, are in danger from introduced earthworms. As the worms move in from surrounding lawns and golf courses, or are introduced as discarded live bait, the ground layer or "duff" in the forest changes. Animals and plants that require the buildup of this duff layer are driven out by the action of the worms.

Stewart makes it clear that there is still much to be learned from studying this humble life form that is capable of so much. The lively prose coupled with her passion for these remarkable creatures makes this a fascinating, funny and informative treat.