DEFINITION OF TERMS


Temperature is important because of its influence on water chemistry. The rate of chemical reactions generally increases at higher temperature, which in turn affects biological activity. An important example of the effects of temperature on water chemistry is its impact on oxygen; warm water holds less oxygen that cool water.  Read EPA's explanation of the importance of this variable:  http://www.epa.gov/volunteer/stream/vms53.html. Temperature is given in degrees Celsius - to convert to Fahrenheit use this formula: F=(degrees Celsius x 9)/5 + 32 or use one of the handy websites such as: http://www.wbuf.noaa.gov/tempfc.htm.

pH  is a measure of the acidity or alkalinity of water, expressed in terms of its concentration of hydrogen ions. The pH scale ranges from 0 to 14. A pH of 7 is considered to be neutral. Substances with a pH of less that 7 are acidic; substances with pH greater than 7 are basic.  The scale is logarithmic so a 1 unit pH change reflects 10 fold change in acidity. Read EPA's explanation of the importance of this variable: http://www.epa.gov/volunteer/stream/vms54.html

Dissolved Oxygen (DO) analysis measures the amount of gaseous oxygen (O2) dissolved in an aqueous solution. Oxygen gets into water by diffusion from the surrounding air, by aeration (rapid movement), and as a waste product of photosynthesis. Read EPA's explanation of the importance of this variable: http://www.epa.gov/volunteer/stream/vms52.html

Electrical Conductivity estimates the amount of total dissolved salts (TDS), or the total amount of dissolved ions in the water; or put another way conductivity is a measure of the ability of water to pass an electrical current. Read EPA's explanation of the importance of this variable:  http://www.epa.gov/owow/monitoring/volunteer/stream/vms59.html



Page last updated on: February 12, 2012

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