Aside from water clarity, the color of water in a lake is one of the main attributes that captures people's attention—particularly if the color begins to change. As this circular explains, changes in color can affect the biological productivity of a waterbody including the abundance of aquatic plants and/or algae. However, readers will also learn that most of these changes are the result of natural processes that occur within the watershed. Related topics of discussion include apparent color, true color, suspended and dissolved substances, along with the dynamics of light refraction. The last section provides two empirical models (equations) that can be used to determine if color in a waterbody is the result of algae or suspended solids. 32 pages in length. Chapter headings:
Part 1 Two Ways to Define Color in a Waterbody
Part 2 More About Suspended and Dissolved Substances
Part 3 Light and Color in Water
Part 4Color and Its Influence on Algae and Aquatic Plants
Part 5 Color, Water Clarity and Algae
Appendix 1 How to Use an Empirical Model
Keywords: algae, algal matter, antilogarithm, apparent color, aquatic plants, Botryococcus, chlorophyll, colloidal substances, color, common logarithm, diatoms, dissolved substances, emergent plants, empirical model, floating-leaved plants, humic acids, inorganic matter, light, light absorption, light attenuation, logarithm, long-term color changes, measuring true color, nitrogen, non-algal matter, non-organic matter, nutrients, organic matter, PAC, PAR, Percent Area Covered, Photosynthetic Active Radiation, PVI, Percent Volume Inhabited, pollen, phosphorus, platinum cobalt units, Secchi depth, Secchi disk, submersed aquatic plants, suspended substances, total chlorophyll, total nitrogen, total phosphorus, true color, tannins, Tsala Apopka Chain-of-Lakes, turbidity related color, visible light, water clarity, watershed
Note: Circular 108 is available in Portable Document Format (pdf) only. It can be obtained as a single PDF file by clicking on the "Printer Friendly Version" link above (file size = 2.6 MB).
Photos used with permission as credited.