What are the two key concepts for this section? What percentage of the earth’s surface is covered with water? What is an aquatic life zone? What is salinity and how is it measured? Distinguish between...

What are the two key concepts for this section? What percentage of the earth’s surface is covered with water? What is an aquatic life zone? What is salinity and how is it measured? Distinguish between a saltwater (marine) life zone and a freshwater life zone, and give two examples of each. Define plankton and describe three types of plankton. Distinguish among nekton, benthos, and decomposers and give an example of each. List four factors that determine the types and numbers of organisms found in the three layers of aquatic life zones. What is turbidity and how does it occur? Describe one of its harmful impacts.