Topic 2: Ecosystem ConnectionsWhat can happen when you remove or add fish or nutrients to an ecosystem? Search in your textbook or on the internet for examples of case studies where this has happened and describe the ecological effects of such an addition or subtraction in one or more case studies. Be sure to let us know where you got the information, and try to focus your attention on aquatic ecosystems involving fishes.  Useful search terms might be invasive species, introduced species, overfishing, extinction, extirpation, eutrophication, runoff, alternative stable states, and trophic cascades. Once we’ve accumulated some good examples, try to answer the following questions. Is it easy or hard to predict what will happen when we perturb an ecosystem? Why or why not?