Turbidity provides a measure of the clarity of the water. As water becomes more murky, turbidity increases. Turbidity is caused by inputs of suspended and dissolved solids in the water which decreases the amount of light penetration. Sources contributing to turbidity include:
Soil erosion
Runoff
from urban and agricultural areas
Wastewater
and stormwater inputs
Algae
and plant materials
Abundant
bottom feeders stirring up sediment
Turbidity interferes with the growth of aquatic organisms by decreasing light levels needed for photosynthesis; and contributing to decreased oxygen concentrations and increased water temperature, which may stress aquatic organisms. Materials causing turbidity may also be responsible for clogging fish gills, reducing available habitat, interfering with egg and larvae development, smothering fish eggs and aquatic insects larvae, and suffocating newly-hatched insect larvae.
Often secchi discs are used to as an alternative to measuring actual turbidity. Secchi disks are round disks, usually black and white, that provide information on the amount of light penetration into a water body. The higher the secchi depth reading, the lower the turbidity and vice-versa.
