1. There are several different physical parameters, or measurable factors, that affect water quality. The first is temperature. In general, the cooler the temperature of water is, the higher its quality will be. Temperature fluctuations or swings may indicate that something is affecting water quality. Many of the organisms that live in and depend on the water may not be able to survive large temperature fluctuations.

2. Another important physical parameter is turbidity, which is a measure of the suspended solids present in the water. (how cloudy or clear the water is ) Sometimes we can see the turbidity of water: if a stream bank has collapsed and a lot of mud enters the water, the water may look cloudy. If water is too turbid, the temperature can increase, among other detrimental consequences.

3. Some of the different chemical parameters used to measure water quality include dissolved oxygen, pH level, salinity, and nitrates. Dissolved oxygen is a measure of how much oxygen the water holds; the more oxygen, the better. Water’s pH level tells us if the water is acidic, neutral, or basic. Salinity tells us how much dissolved salts are in the water, and nitrates are chemicals that can adversely affect the quality of water

4. Where is most of Earth’s freshwater located? a. In the ocean b. In polar ice caps c. In lakes and rivers d. In underground aquifers

5. What are the most likely effects of ocean upwelling? a. Decreased photosynthesis and increased chemosynthesis b. Increased nutrients and increased populations of algae and fish c. Increased pollution and decreased animal and plant populations d. Increased water temperature and decreased dissolved oxygen

6. What is the most immediate effect of high levels of nitrates and phosphates in a body of water? a. The pH decreases b. The population of algae increases c. The fish population decreases d. The levels of dissolved oxygen decrease

7. Which pair indicates a healthy water source? a. High levels of phosphates and algae b. High levels of dissolved oxygen and the presence of fish c. High salinity and an absence of insect larvae d. Low turbidity and high pH levels