Nematode (Round worm)
Length:0.3-1.5 mm (a line of 20 would stretch across a postage stamp).Lifespan:Unknown.
Total Nematode Population:up to 30 million per square meter (5,000 in one teaspoon of soil).
Go anywhere in the soil and you're likely to bump into a roundworm, or nematode at work. They're the most common multi-cellular animals in soil. And they live all over the world. Roundworms also live as parasites in animals, including people. They aren't related to earthworms at all. Roundworms belong to a very exclusive group of animals—they're the only members!
Don't be fooled by their plain looks. Nematodes feed at every level of the soil food chain. This species hunts for bacteria. It swallows them whole and digests them in its gut. Other kinds of soil roundworms eat dead organic matter. Some prey on protozoa and other nematodes. Still others eat fungus. Roundworms that eat and live in plant roots can badly damage farm crops and flowers.
Nematodes wriggle their way through the thin film of water between soil particles. Some kinds of fungus actually trap nematodes in little nooses. Once the nematode is stuck, the fungus digests it.
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Pictures: Saskatchewan Interactive/Dr. Jeff Bettany | Point Pelee National Park, Canada |
Ana Luisa Child | Sven Boström