Water Chemistry Notes (pgs 305 - 311 text)
 Water quality of ecosystems is dependent on ____________, ____________, and
____________ factors.
 When substances in water are ____________ to the organisms that live there, the water is
considered ____________.
 Dissolved oxygen “D.O.” (chemical)
- This is the most ____________chemical requirement for aquatic organisms.
- Water mixes with air when it falls over rocks and waterfalls ____________ the level of
D.O.
- Standing or slow moving bodies of water have ____________D.O. than fast moving water
bodies.
- ____________increases D.O. as ____________by aquatic animals decreases it. (Remember
the ____________-____________cycle?)
- Water polluted with organic matter has ____________D.O. than clean water because
____________of the organic matter use up the D.O.
- Most fish cannot live with D.O. less than__ ppm.
low ____ ppm
medium _____ ppm
high _____ ppm
 Temperature (physical)
- As temperature increases ____________D.O can be held in the water.
- Trout require high levels of D.O. which is why they live in coldwater streams.
- ____________ pollution occurs when industries (power plants) use water for cooling. The
hot water is dumped into aquatic systems raising the temp.
 Turbidity (physical)
- It is the measure of the amount of __________scattered or absorbed by particles in water
(____________).
- Eroded soil in water __________turbidity, clogs ____________, and ____________aquatic
insects.
 pH (chemical)
- Few aquatic organisms can live in water with pH lower than ___ or higher than ___.
- Best range: fish 6.7 - 8.6
- CO2 produced from decaying organisms forms ____________ ____________decreasing
pH.
- ____________acid in water comes from ____________and acid rain (burning fossil fuels)
decreasing pH.
- ____________ industrial waste (bleaching plant) can increase pH.
 Hardness (chemical)
- Water with ____________minerals is considered hard.
- Water containing ____________and ____________is said to be hard.
- The minerals in hard water can ____________acidic rain water.
- Calcium is needed for __________, __________and other shelled organisms.
soft ________ ppm
________ ppm
med ________ ppm
hard
 Nitrates and Nitrites (chemical)
- Runoff of ____________, ____________, & ____________ are major sources.
- Excessive nitrogen causes algae population to explode (________________)
- Most nitrogen is constantly used up in the system. More than ___ ppm indicates excess.
- When the algae dies it decomposes using up the D.O.
 Phosphates (chemical)
- Comes from the ____________sources as nitrogen as well as some industrial processes.
- Also causes ____________ ____________.
- ____________as harmful to humans or animals as nitrogen.
- More than ____________ppm Indicates excess.