Healthy Rivers Water Chemistry

Dissolved Oxygen oxygen gas dissolved in liquid water. Why is Dissolved Oxygen (DO) Important? Why is Dissolved Oxygen (DO) Important? Aquatic animals need oxygen to breathe. Aquatic animals need oxygen to breathe.

Physical Factors Influencing DO a.  temp  DO/  temp  DO - temperature most important physical factor influencing O 2 solubility a.  temp  DO/  temp  DO - temperature most important physical factor influencing O 2 solubility b.  turbulence  DO (mixes H 2 O with atmospheric O 2 - atmosphere is 21% O 2, so mixing between air and H 2 O is an important source of DO) ideal is high velocity flow b.  turbulence  DO (mixes H 2 O with atmospheric O 2 - atmosphere is 21% O 2, so mixing between air and H 2 O is an important source of DO) ideal is high velocity flow over shallow substrate, creating riffles over shallow substrate, creating riffles

Biological Factors Influencing DO a. biological influences - aquatic plants can become the dominant factor controlling DO during the summer months. a. biological influences - aquatic plants can become the dominant factor controlling DO during the summer months. photosynthesis produces oxygen (day) 6CO 2 + 6H 2 O + light  C 6 H O 2 respiration consumes O 2 (night) C 6 H O 2  6CO 2 + 6H 2 O + energy C 6 H O 2  6CO 2 + 6H 2 O + energy

Biological Factors Influencing DO

Biological Influences On Dissolved Oxygen Decomposition - if organic waste (dead algae, dead organisms, manure, shoreline vegetation, wastewater) is present  DO Decomposition - if organic waste (dead algae, dead organisms, manure, shoreline vegetation, wastewater) is present  DO

Turbidity  What is turbidity?  The amount of suspended soil particles (sediment) or algae present in water.  Why is turbidity a concern?  Blocks light needed for photosynthesis.  Reduces visibility for visual feeders.  Smothers fish and amphibian eggs.

What Causes Turbidity? Erosion and runoff of soil – usually caused by rain Erosion and runoff of soil – usually caused by rain Human disturbance increases erosion of soil and organic matter and nutrient runoff which enhances algal growth Human disturbance increases erosion of soil and organic matter and nutrient runoff which enhances algal growth

What Causes Turbidity? Suspended algae can be a major problem in the summer. Suspended algae can be a major problem in the summer. Wind, waves, bottom feeding fish, and mammals walking through a stream can re- suspend settled sediment. Wind, waves, bottom feeding fish, and mammals walking through a stream can re- suspend settled sediment.

What is pH? A measure of how acidic or basic a solution is. A measure of how acidic or basic a solution is.

pH Why is pH important? Why is pH important? Aquatic organisms are sensitive to high or low pH, especially less than 6.5 or more than 8.5. Aquatic organisms are sensitive to high or low pH, especially less than 6.5 or more than 8.5. The reproductive portion of the growth cycle is particularly sensitive, so while adults may continue to live, they will not reproduce. The reproductive portion of the growth cycle is particularly sensitive, so while adults may continue to live, they will not reproduce.

Macroinvertebrates Animals without a backbone, large enough to be seen with the naked eye. Animals without a backbone, large enough to be seen with the naked eye. Indicators of stream health, important parts of the food chain. A healthy stream will contain high diversity of species and more pollution sensitive species.