LESSON 4: THE DISAPPEARING DONUT: AN AQUATIC INVASIVE SPECIES CASE STUDY Students will learn about the invasive species and how they can impact native ecosystems. Using data from university research studies around the phytoplankton levels in Lake Michigan over the last 30 years, students will investigate how many factors combine to play a role in the complex aquatic ecosystem and decide how humans can minimize their impact on the Great Lakes Ecosystem.