Microzooplankton are microscopic animals that float around in water. Let's look at the word: 'micro' means small. It usually means something so small you can't see it without using a microscope. 'Zoo' means animal. A zoo is a sort of nickname for zoological garden. 'Plankton' are small living things that move around in the water.

There are lots of different species of zooplankton. Some are 'macrozooplankton,' meaning that they're big enough to see without magnification, but they're still pretty small. There are also phytoplankton, which are tiny aquatic plants. We tend to think that small things are unimportant, but what would happen to the aquatic food web if microzooplankton disappeared?