What Kinds of Organisms Have Lived in a Lake? DNA Tells Us!

There are many organisms living in lakes, for example, fish, aquatic plants, microalgae, and bacteria. But have you wondered what organisms have inhabited a lake throughout its history? Are there any species that are no longer found in the lake today? Has the ecosystem changed over time? When they die, most lake organisms leave their remains (pollen, shells, fossils, and DNA). Remains are preserved for many years in the sediments deposited at the lake bottom. Scientists are using an exciting technology that identifies organisms from DNA extracted from sediments that are over 100 years old. In this article, we will tell you how DNA is preserved in sediments at the bottom of lakes and how it is used to find out which organisms were present in the past and which are still living in a lake today.