Last full moon, a friend looked at the shitake mushrooms on a stump out back and asked what was the black stuff coating some of the mushrooms. The next morning I looked at the "gritty dust" and saw that the little black dots would occasionally jump. A light went on, and I realized that these dots were "springtails," tiny arthropods that I had read about recently in a great book, "Teaming with Microbes". Springtails eat fungus, but usually they are in the soil, often in great number. Their presence is an indication that the soil is healthy. I had recently disturbed both the soil and the stump when I cut down two alders that, by their pronounced lean, were threatening the woodshed that I was about to rebuild after the dilapidated old one had been damaged by another alder.
Then, seemingly unrelated, a purple scum started to form on my pond. I thought maybe it was weathered oil, possibly from the nearby parking area and road, but that did not seem quite right. A week or so later, I saw some of the scum on a puddle on the berm on the south side of the pond, where it could not have come from a car. I gathered some in my hand to smell it for oil, and saw that it was alive, made of little dots, and sometimes the dots jumped--springtails!
The springtails I have currently been seeing live mainly in the soil, eating leaf and soil detritus, especially the fungal parts. The taxonomy of springtails is confusing and changing, but I am pretty sure there are thousands of species of various sizes and shapes. They are not insects because insects have external mouth parts and these critters have internal mouths. They are harmless to humans and really quite interesting. And as I said previously, they are a sign of a good soil web. I read that a cubic meter of topsoil commonly contains a 100,000 of them. I imagine there were many millions of them on the pond. There is ice on the pond now. It will be interesting to see if their numbers decrease because of the freeze. The web of life is far more interesting when I recognize what I am looking at. When I do, I see more, everything makes more sense, and it all gets even more interesting.