Copepod

Pictured is a copepod one of various types of zooplankton that sustain life in the Great Lakes.  This photo was taken through a microscope.

Plankton, phytoplankton and zooplankton feed small fish and are at the base of food pyramids in water. Read more about food pyramids in the Great Lakes in my book, The Dynamic Great Lakes.  Available at bn.com in a new edition.

Great Lakes Plankton

Zooplankton in the Great Lakes such as this copepod pictured are a little less numerous than the phytoplankton they feed upon. Invasive species such as zebra mussels and quagga mussels deplete the waters of food important to immature fish and other parts of the food pyramid.
For more information about Great Lakes biota, read
The Dynamic Great Lakes.