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The Roving Microscope – Fieldnotes #2

Danielle's wormery

‘Good compost has per teaspoon 1 billion bacteria, 400 to 900 feet of fungal hyphae, 10,000 to 50,000 protozoa and 30 to 300 nematodes. Compost can inoculate, maintain, or alter a soil food web in a given area.’

Jeff Lowenfels and Wayne Lewis, Teaming with Microbes – A Gardener’s Guide to the Soil Food Web (Portland, Oregan: Timber Press, 2010), p. 131.

There are three basic shapes of bacteria represented in this sample taken from Danielle’s wormery: coccus (round or oval); bascillus (rod-shaped); and spiral (corkscrew).

A microscope image of an amoeba surrounded by bacteria (magnified x 400)

The large roundish organism on the left is an amoeba, the hundreds of assorted round and rod-shaped organisms are bacteria.

A microscope image of a nematode (magnified x 100)

This worm-like organism is a nematode – it looks like a fungal feeder. The dark clumps are the organic matter, and there are lots and lots of bacteria across the whole slide, which is a sign of healthy compost.

A microscope image of a spirilla bacteria (magnified x 400)

The corkscrew shape running top to bottom is a pathogen. This is not a good sign; it is most likely an indicator that the compost is too wet and starting to become anaerobic. The best thing to do in this situation is to oxygenate the compost by adding shredded paper or cardboard, which will soak up the excess moisture. The worms need oxygen, so adding some paper will help. The large brownish clumps are organic material. Many cocci bacteria (round or oval) and bacillus bacteria (rod-shaped) are visible.

A microscope image of a testate amoeba (magnified x 400)

The large organism in the centre of the image is a testate amoeba. It makes a shell called a test from debris, which provides a shelter for the amoeba inside and protects it from predators. You can see that it is feeding on bacteria. On its left is another amoeba, which is also feeding on the surrounding smaller bacteria. The dark circle below is a spore, an indicator of fungi or mould. This is normal and presents no problem for vermicomposting.

A microscope image of a testate amoeba surrounded by cocci and bacillus bacteria (magnified x 100)

The larger organisms are testate amoebae, who are busy feeding. The presence of so many cocci and bacillus bacteria indicates that the vermicompost is healthy.

A microscope image of a cheese mite

A microscope image of a cheese mite (magnified x 100)

These images are an added extra; they do not come from Danielle's compost. This is a cheese mite taken from the rind of some cheese. It looks enormous through the microscope, but is invisible to the naked eye – quite a shocker!