Water Quiz Study Guide—“Answers”
1. Water properties and importance (dissolve, universal solvent) Water is known as the universal solvent because of its ability to dissolve many things. It is also polar, has a density of 1 g/cm3, is less dense when a solid (ice), and has properties of both adhesion and cohesion.
2. Hydrology—the study of water on Earth
3. Hydrosphere—all of the liquid water resources on Earth. Related to the other spheres—Ecosphere, Biosphere, Pedosphere, etc.
4. Percentage of water in various resources (Oceans, Lakes, Rivers, etc.) Ocean is largest percentage—97%, ice 1.2%, underground water 0.5%, Surface water 0.02%
5. Groundwater (Amounts, uncertainty in amounts, locations) Groundwater could be as high as 19% of Earth’s water. This is the most uncertain of the amounts due to questions about the amount of water in the lower Lithosphere (large lake?) and the amounts stored in rocks in the ground.
6. Aquifier—a geologic formation that possesses both porosity and permeability
7. Water Table—the surface below which pores and rocks are water filled
8. Watershed—an area of land that collects, stores, and releases water to a common point such as a river, stream or lake.
9. Water cycle and processes (Evaporation, Condensation, Precipitation, Runoff, etc.)—The water cycle :
Note: Transpiration is a part of the water cycle as is the cycling of water through ice and groundwater seepage.
10. Percent of water available for human us-Less than 1% of Earth’s water is available for human use. (Actually 0.3% is available for use by humans)
11. Water stewardship—the careful management of water resources so that they will remain clean, ecologically sustainable and available for future use.
12. Water quality and its importance—humans use/consume water to live as do other organisms, water is limited, provides habitat for creatures, is an environmental indicator, and is an important transportation system for ecosystems.
13. Clean Water Act—Passed in 1972, regulates the discharge of pollutants in US waters.
14. Safe Drinking Act—Passed in 1974, establishes safe drinking water standards for all US citizens
15. Water Quality Act—Passed 1987, requires EPA to regulate storm water runoff
16. Temperature effects on water quality—temperature affects metabolic rate of fish and aquatic creatures, affects rate of chemical reactions and gas absorption including amount of potential dissolved oxygen.
17. Dissolved Oxygen (Percents, effects, temperature dependence)à 60% or 5 ppm is considered good for most aquatic organisms, less DO results in less growth and/or death of animals. DO is temperature dependent—higher temp can dissolve less oxygen.
18. pH (Scale, safe range for water organisms)—pH is related to the H ion concentration in water—essentially how much acid/base a substance is. A pH range of 6.5 to 8.2 is considered ideal for most aquatic organisms. Pure water has a neutral pH of 7. Lower pH is acidic, higher pH is basic/alkaline.
19. Alkalinity (measured, and effects of high/low amounts)—a measure of the amount of calcium carbonate in water. Acts as a buffer against toxic metals and acids—will react with them, neutralizing or reducing their effects. 30-70 ppm is typical, over 100 ppm is considered good.
20. Hardness (measured, and effects of high/low amounts)—measured as dissolved calcium AND magnesium compounds in the water. Hardness helps to buffer and can trade off calcium and magnesium salts in chemical reactions when buffering capacity is reduced. Hardness of 120 ppm or better is considered hard water.
21. NC Hardness amounts in general. NC generally has moderately hard water in the 30-80 ppm range.
22. Buffering by Alkalinity and Hardness—both act as a buffer against toxins.
23. Nitrates (sources and effects of high amounts)Nitrates come from animal wastes and fertilizers. High amounts indicate excessive nutrients and can lead to Eutrophication
24. Phosphates (sources and effects of high amounts)—come from fertilizers and detergents. High levels > 5ppm indicated too many nutrients, possible spillage, and Eutrophication
25. Eutrophication—process whereby excessive nutrients lead to a depletion of dissolved oxygen in the water and potential death of aquatic animals.
26. Turbidity (sources and effects of high amounts)—the clarity of water, determined by amount of suspended sediments. Excessive levels >50 JTU can smother benthic organisms and reduce sunlight penetration.
27. Water cleaning methods (aeration, flocculation, carbon absorption, reverse osmosis)-aeration—introduction of air to remove gases, flocculation—using chemical treatments to precipitate toxins, carbon absorption—uses activated carbon to react with some organics, reverse osmosis—pressure, membranes, and chemicals used to remove many toxic substances from water.
28. Water pollution (effects on environment)—can include decreased diversity of organisms, eliminate intolerant organisms, cause shifts in ecosystem balance.