Why Study Water

Surface– Dirt

Minerals Organic materials (any once living thing now decomposed Fertilizer Chemicals Anything spilled

Ground – aquifers

How is material moved in watersuspendeddissolved

Water Chemistry

Substances are moved downstream in two ways

Dissolved –become a permanent part of the water.

Suspended- carried by the water but not a permanent part of the water

pH

pH indicates how much acid is in the water (actually it is the amount of hydrogen ions in a sample).

Scale from 0-14 7 is considered neutral Above seven 8-14 is a base 0 to 7 are acids

– Examples: when carbon dioxide is removed from the water the pH increases. If carbon dioxide is added pH decreases.

– A pH of 6.5-8.2 is considered best for fish.

Oxygen and carbon dioxide

Photosynthesis- the process by which green plants use energy from sunlight to convert carbon dioxide and water into simple carbohydrates (sugars) and as a waste plants give off oxygen

Respiration; Plants and animals continually respire taking up oxygen and producing carbon dioxide. In respiration stored chemical energy is released when sugar and oxygen are converted to carbon dioxide and heat.

– Like land animals fish need oxygen in order to survive and grow. Fish (and other aquatic animals consume oxygen and produce carbon dioxide

– Oxygen is also used up when organic material, such as human and animal waste and plant debris, decompose in water.

Nutrients

Nutrients such as nitrogen and phosphorous act as fertilizer for aquatic plants. When dissolved nutrient levels are high, excessive plant and algae growth create water quality problems and speed up the natural process of eutrophication- the filling in of lakes and ponds by plant material. Nutrients get into the water from human and animal waste, decomposing organic matter, and runoff of fertilizer from lawns and crops.

Water Testing

In the pH test, chemical indicators, sensitive to pH, change to specific color at certain pH levels

In the tests for ammonia oxygen and nitrate, the test reaction produces a color according to the concentration of the substance being measures. The higher the concentration of the dissolved substance, the darker the color produced in the test reaction