Common name: Muck, Rotting Stuff
Scientific name: Detritus (pronounced
Habitat: bottom of vernal pools and other water bodies.
Size: microscopic to big chunks
Description: Detritus is all the dead stuff that sinks to the bottom of a vernal pool. It contains pieces of dead plants, dead animals and animal wastes (feces). It is usually black or brown. Although detritus is dead, it is crawling with living microscopic critters.
Fun facts: The larva of a midge (a type of fly) lives in the detritus on the bottom of some vernal pools. The midge larva looks like a worm with a hard, brown head. It makes a sack for itself (like a sleeping bag), which it covers with detritus. The detritus cover is perfect camouflage to hide the midge larva from its predators. It is almost invisible as it hunts for food on the bottom of a vernal pool.
Ecology: Detritus is very important to the vernal pool food web. Almost any critter that lives in a vernal pool either eats detritus or a critter that eats detritus. Detritus is covered with many species of Bacteria. Bacteria are decomposers. When Bacteria eat detritus, they are recycling the energy from the dead bodies of plants and animals into their own living bodies. The mix of detritus and Bacteria is then eaten by Protozoa, aquatic earthworms, Seed Shrimp, Water Fleas, Rotifers, Copepods, Fairy Shrimp and Tadpole Shrimp.
Detritus provides a home for many small critters that live on the bottom of a vernal pool. Detritus is always being made, because something is always dying (or dropping feces) in this busy food web. The recycling of detritus shows us that death is an important part of life in every vernal pool.
Investigate: With help from your classmates, make a list of all the vernal pool species that eat detritus. Imagine what would happen if there were no decomposers in the vernal pool food web.
When you visit vernal pools, be sure to look for a midge larva camouflaged with detritus. Watch how it slides its head out of its protective sack to hunt for food.
Few people have heard of the large group of flies called midges. Search for more information about midges. Does the adult midge look like any other flying insect that you know?