The Unseen World in the River

Every living thing needs food, also known as nutrients. In nature, living things are connected through food webs. Food webs show us how animals and plants are related through feeding relationships, like birds eating fish. But how do nutrients get returned back into the food web? The answer is bacteria! Bacteria are impossible to see with the naked eye. But, they are found almost everywhere in the world and are very important for recycling nutrients within habitats, like a river. Scientists use the DNA of bacteria to figure out which bacterial species are present and how these different bacterial species recycle nutrients in a river. Knowing which species are present helps scientists to use bacteria to monitor changes in river habitats. These changes might include the amount of food that is available for larger animals. Bacteria are considered to be the base, or foundation, of the food web, and paying attention to early changes in bacteria may allow us to prevent more extreme changes from causing problems later on for larger creatures.