13RIVER BOTTOM CRITTERS

Stirring up the water to net some critters!
Stirring up the water to net some critters!
Scientists collect the benthic flora by kicking up the dirt at the bottom of the river, and then dragging a net through the cloud that comes up. The dirt and debris, which includes benthic flora, is trapped in the net. Then the sample is taken to the lab for study. Scientists try to count at least 200 organisms in each sample to get a good idea about which benthic flora are living in the river. Some are large enough to see with your eyes, but for others you need a microscope. The organisms found are then used to create an FBI value (Family Biotic Index), a measure that tells how clean the river is.

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