Dr. Marla Schwarzfeld and Victoria Nowell (AAFC) displayed mites extracted from soil at FWG and elsewhere, just visible under 10X scopes.

by Lynn Ovenden

For the mite workshop on July 12, participants arriving at Fletcher Wildlife Garden found the entry bedecked with a line of stained shredded undies. This was the result of a SoilYourUndies experiment conducted by five FWG volunteers following the Soil Conservation Council’s protocol. In early May, each pair of 100% white cotton underwear was buried in a different habitat, leaving only the waistband above ground. After 8 weeks in the soil, each pair was unearthed for us to see.

Decomposition of the cotton into shreds indicates biological activity which is important for soil health. A multitude of tiny organisms in soil feeds growing plants by turning dead plant material into useable nutrients. They also help create soil organic matter, which holds water and reduces the risk of soil erosion.

Isabelle, Barbara, Catherine, Michelle and Sandy (left to right) stand behind the results of decomposition in their respective habitats: Ontario bed, butterfly bed, new woods, B_H-trail woods, rich forest).

In our experiment, the pair of undies reduced to mere shreds (righthand side of photo) had been buried in a rich forest with ferns and fir trees, well outside of Ottawa. The other four undies were +/- half gone; they had been buried at FWG, in the butterfly bed and sunny Ontario beds of the Backyard Garden, in the new woods behind the baseball field and in the entryway woods along the Bill Holland trail. If our goal at FWG were to create soil with the biological activity of rich forest, we still have a ways to go. Fletcher volunteers are constantly adding compost, leaf mulch and more plants to these habitats; we trust these actions contribute to soil health.

After we all took photos of the undies and introduced ourselves, Dr. Marla Schwarzfeld treated us to an entertaining overview of soil mites, complete with jokes, exquisite images (some credited to Andy Murray, www.chaosofdelight.org) and short videos, showing some bumbling, trudging, scurrying, preening, and stealth behaviours of the very foreign world at our feet.

Bdellid mite from litter collected in a deciduous forest near Pink Lake in Gatineau Park, Quebec. Photo by Victoria Nowell.

Marla and Victoria Nowell are acarologists in the research branch of AAFC, developing expertise and knowledge about soil mites. They estimate that much fewer than 10% of mite species are known to science and that detailed study of almost any soil sample reveals new species.

Dr. Marla Schwarzfeld shows how to set up a Berlese funnel to extract soil organisms from soil into a jar that will be screwed onto the bottom of the funnel.

We saw pictures of mites from the three major groups of mites: oribatids with their round turtle-like shells (they mostly scavenge for fungi and dead plants and insects), mesostigmatids which are more elongate, predatory, and have their breathing hole at mid body, and prostigmatids in which the breathing hole is typically up front close to the itty-bitty slashing mouth parts.

Marla and Victoria then showed us how to extract soil organisms from grab samples of soil using a Berlese funnel. Heat from a light bulb in the lid chases the insects and mites down through a cheesecloth filter into a jar beneath the funnel. Extractions had been set up for two soil samples the night before so we could see tiny moving mites under the 10X microscopes. It took patience and a quick eye to see them on the damp bottom of the jar. We also looked at more concentrated collections of mites that had been extracted into alcohol at study sites elsewhere in Ontario and Quebec.

Everyone left the evening with thanks to Marla and Victoria for opening our eyes to this microscopic cosmos and the skill of those who can show us its wonders.