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| Water mite. |
Freshwater invertebrates are an incredibly diverse,
although generally inconspicuous, group of animals. Despite their low
profile, they play such an essential role in the aquatic ecosystem that
the River as we know it would not exist without them.
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| This Leptocerus
americanus protrudes from its case to feed. |
For example, aquatic insects are important because they
recycle nutrients (they eat dead and decaying plant and animal matter
and bacteria like E. coli)
and they are a primary source of food for other animals and certain plants.
In the Rideau River, many of the aquatic invertebrates
are the larval stages of insects, such as caddisflies, mayflies, dragonflies,
mosquitoes and chironomids. However, there are many other invertebrates,
including crayfish, worms, mussels, snails, and
leeches. Some of the less visible and perhaps more unfamiliar invertebrates
include many of the crustaceans (amphipods, copepods and ostracods), flatworms
and water mites.
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| Aquatic
snail of the Physidae family. |
Aquatic invertebrates occupy many different feeding
niches, from deposit
feeders and filter feeders to herbivores and predators, which
feed on other invertebrates or even small vertebrates like tadpoles, frogs
and small fish.
During 1999, the Rideau River Biodiversity Project scientists and volunteers identified more than 150 species of invertebrates living among submerged aquatic plants in the Rideau River. Many were photographed live under a microscope. These photographs are an invaluable resource.
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| Crayfish. |
During the summer of 2000, the invertebrates that live on the river bottom were sampled by taking sediment cores. The identification of hundreds more species is expected to result from the analysis of these cores.
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