The document discusses the formation and ecology of lakes. It describes how lakes form naturally from glacial scouring, sediment deposits from glaciers, and crustal movements. Lakes can also form after volcanic eruptions when rain fills the collapsed caldera. Human-made lakes occur when dams are constructed. The document then covers the different life found in shallow and deep zones of lakes, how sediment and nutrients affect lakes over time leading to eutrophication, and the seasonal turnover of nutrients in deep lakes.

2. Chapter: Freshwater at Earth’s Surface Table of Contents Section 3: Wetlands Section 1: Streams Section 2: Lakes and Reservoirs Section 4: Pollution of Freshwater

19. Section Check 2 Question 1 What process eventually can turn a lake into dry land? A. crustal movements B. eutrophication C. turnover D. upwelling NC: 3.02

20. Section Check 2 Answer The correct answer is B. Eutrophication is when a lake experiences an increase in nutrients through the process of decaying organisms. Eventually, the lake will become dry land. NC: 3.02

21. Section Check 2 Question 2 What is a lake called when the water is used for human consumption? When a dam is built a human-made lake, or reservoir , forms. The reservoir is used to supply drinking water to nearby communities. Answer NC: 3.02

22. Section Check 2 Question 3 How did the lake in this photo form?

23. Section Check 2 Answer This lake formed after a volcanic eruption occurred causing the top of the volcano to sink into itself. The depression, called a caldera, has filled with rainwater and runoff.