HealthyHealthy Rivers Rivers

Water ChemistryWater Chemistry

Dissolved OxygenDissolved Oxygenoxygen gas dissolved in liquid oxygen gas dissolved in liquid

water.water. Why is Dissolved Oxygen (DO) Why is Dissolved Oxygen (DO)

Important?Important? Aquatic animals need oxygen to Aquatic animals need oxygen to

breathe.breathe.

Physical Factors Influencing Physical Factors Influencing DODO

a. a. temp temp DO/ DO/ temptempDO - temperature most important DO - temperature most important physical factor influencing O physical factor influencing O2 2 solubilitysolubility

b. b. turbulence turbulence DO (mixes H DO (mixes H22O with atmospheric OO with atmospheric O22 - - atmosphere is 21% O atmosphere is 21% O2, 2, so mixing so mixing

between air and Hbetween air and H22O is O is an important source of an important source of DO) ideal is high velocity flow DO) ideal is high velocity flow

over shallow substrate, creating rifflesover shallow substrate, creating riffles

Biological Factors Influencing Biological Factors Influencing DODO

a. biological influences - aquatic plants can a. biological influences - aquatic plants can become the dominant factor controlling DO become the dominant factor controlling DO during the summer months. during the summer months. photosynthesis produces oxygen (day)photosynthesis produces oxygen (day)6CO6CO22 + 6H + 6H22O + light O + light CC66HH1212006 6 + 6O+ 6O22

respiration consumes Orespiration consumes O2 2 (night)(night) CC66HH1212006 6 + 6O+ 6O2 2 6CO 6CO22 + 6H + 6H22O + O +

energyenergy

Biological Factors Influencing Biological Factors Influencing DODO

Biological Influences On Biological Influences On Dissolved OxygenDissolved Oxygen

Decomposition - Decomposition - if organic waste (dead algae, if organic waste (dead algae, dead organisms, manure, shoreline vegetation, dead organisms, manure, shoreline vegetation, wastewater) is present wastewater) is present DO DO

TurbidityTurbidity What is turbidity?What is turbidity?

The amount of suspended soil particles The amount of suspended soil particles (sediment) or algae present in water.(sediment) or algae present in water.

Why is turbidity a concern?Why is turbidity a concern? Blocks light needed for photosynthesis.Blocks light needed for photosynthesis. Reduces visibility for visual feeders.Reduces visibility for visual feeders. Smothers fish and amphibian eggs.Smothers fish and amphibian eggs.

What Causes Turbidity?What Causes Turbidity? Erosion and runoff Erosion and runoff

of soil – usually of soil – usually caused by raincaused by rain

Human disturbance Human disturbance increases erosion of increases erosion of soil and organic soil and organic matter and nutrient matter and nutrient runoff which runoff which enhances algal enhances algal growthgrowth

What Causes Turbidity?What Causes Turbidity? Suspended algae can be a major Suspended algae can be a major

problem in the summer.problem in the summer.

Wind, waves, bottom feeding fish, and Wind, waves, bottom feeding fish, and mammals walking through a stream can mammals walking through a stream can re-suspend settled sediment.re-suspend settled sediment.

What is pH?What is pH? A measure of A measure of

how acidic or how acidic or basic a solution basic a solution is.is.

pHpH Why is pH important?Why is pH important?

Aquatic organisms are Aquatic organisms are sensitive to high or low sensitive to high or low pH, especially less than pH, especially less than 6.5 or more than 8.5.6.5 or more than 8.5.

The reproductive The reproductive portion of the growth portion of the growth cycle is particularly cycle is particularly sensitive, so while sensitive, so while adults may continue to adults may continue to live, they will not live, they will not reproduce.reproduce.

MacroinvertebratesMacroinvertebrates Animals without a backbone, large Animals without a backbone, large

enough to be seen with the naked enough to be seen with the naked eye.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.