Temperature Fact Sheet

Definition: A numerical measurement in degrees Celsius (C) or Fahrenheit (F) of heat

Celsius = (F- 32.0)           1.80

Fahrenheit = (C * 1.80) + 32.0

Background:

• Many of the physical, chemical, and biological characteristics of a waterway are directly linked to the water temperature.
• The sun provides the energy needed to affect water temperatures, so shading influences temperature
  
  

 

• The shallower the water, the quicker water temperatures will change
• Moving water (stream, rivers, especially riffles and rapids) of water are normally cooler than standing water, (ponds, lakes).
• Temperatures in lakes may be stratified in layers dependent upon season of the year

• Lower temperatures hold more oxygen, higher hold less
• Higher temperatures increase aquatic organism's metabolic rates, i.e. increase oxygen need
• Higher temperatures increase plant growth and decomposition rates
• Different species have differing and specific ideal temperature ranges

Thermal Pollution

Definition: A type of pollution which occurs when relatively warmer or colder water enters a body of water, causing unnatural changes in the temperature of the body of water

Why is this bad?

An aquatic organism's body temperature is directly linked to water temperature. Thus, the organism need time to adjust to any change in water temperature. Sudden changes in water temperature, as in thermal pollution, places stress on the organisms too quickly to allow for adjustment to the changing temperature. A thermal change of > 2° C per day is harmful. If thermal pollution is severe, then the entire aquatic ecosystem can be destroyed.  

Origins of Thermal Pollution:

• Industries & power plants--- warm discharge water used to cool hot machinery.

• Stormwater---running off of hot urban surfaces such as pavement

• Cutting of trees along waterways which otherwise shade the water from the sun

• Increased turbidity, i.e. water cloudiness---cloudy water absorbs the sun's rays