While watching the sand "boil", it doesn't take long before you notice the amphipods - active little crustaceans - commonly called scuds. The scuds are continuously zipping around exploring the spring. Here is a photo of a scud peeking around the vein of a leaf.
With all their exploring, scuds are sure to encounter other aquatic creatures.
Another very common critter in this winter-bound spring is a small, free-living flatworm called a planaria. Here is a photo of planarias thronging the sand boils
These flat, black worms have eye-spots and sensory organs on their heads which give them a unique look and make them interesting to watch...
Northern Spring Salamanders I've seen crossing the road.
I could keep going with this overview of the aquatic life in my little winter-bound spring. As an example... there are a few things in this frame of this one photo that I haven't covered yet.
tube-building chironomid larva. The upper arrow points to a very small caddisfly larva with a tube of small, white, sand-grains. That minute caddisfly larva is crawling on one of the tubes of the chironomids. The blurry white flecks in the background are copepods and other microorganisms swimming in the water.
This post was an overview of some of the most obvious and active spring-dwellers. What fun to look at this thriving aquatic community! Trust me... we're only started looking what lives in this spring during the winter.
inhabitants of this boiling-sand spring such as the aquatic snails. I might also look at some of them in-depth, if I don't get side-tracked by the Rhododendron or by galls on the saplings.