GLOSSARY

Aeration - the process of supplying air to a lake; promotes degradation of organic matter.

Chlorophyll-a - one type of chlorophyll, the green pigment found in plants.  Measurements of the chlorophyll concentrations in water samples are used to estimate algal biomass in a waterbody and to assess a waterbody's biological productivity.

Eutrophic - one of the four trophic state categories, the eutrophic state is defined as having a high level of biological productivity, second only to the hypereutrophic category.  The prefix "eu" means good or sufficient.  A eutrophic waterbody is capable of producing and supporting an abundance of living organisms (plants, fish, and wildlife).  

Grass Carp - a herbivorous (plant-eating) species of fish (Ctenopharyngodon idella) native to Africa.  Sterile, non-breeding populations have been introduced into some Florida waterbodies to control undesirable plants. 

Hypereutrophic - one of the four trophic state categories, the hypereutrophic state is defined as having the highest level of biological productivity.  The prefix "hyper" means over abundant.  Hypereutrophic waterbodies are among the most biologically productive in the world.  

Mesotrophic - one of the four trophic state categories, the mesotrophic state is defined as having a moderate level of biological productivity.  The prefix "meso" means mid-range. A mesotrophic waterbody is capable of producing and supporting moderate populations of living organisms (plant, fish, and wildlife).

Nitrogen - an element that, in its different forms, stimulates the growth of aquatic plants and algae in waterbodies.

Oligotrophic - one of the four trophic state categories, describes a lake with clear water, low nutrients and few water quality problems; the oligotrophic waterbody is capable of producing and supporting relatively small populations of living organisms (plants, fish, and wildlife); Trophic State Index value below 50.

Phosphorus - an element that, in its different forms, stimulates the growth of aquatic plants and algae in waterbodies.

Secchi depth - (pronounced "secky") a measurement that indicates water clarity.  Traditionally, the transparency or water clarity of a waterbody has been measured by using an 8-inch diameter disc called a "Secchi disc," that was named in honor of its inventor. To use the Secchi disc to measure water clarity, it's lowered into the water to find the depth at which it first appears to vanish from the observer's sight.

Trophic State - the degree of biological productivity of a waterbody.  Biological productivity generally relates to the amount of algae, aquatic plants, fish and wildlife a waterbody can produce and sustain.  

Trophic State Index - a scale of numbers from 1 to 100 that can be used to indicate the relative trophic state of a waterbody.  Low TSI values indicate lower levels of biological productivity, and higher TSI values indicate higher levels.  

Watershed - the area from which water flows into a waterbody.  Activities in a watershed, regardless of whether they are natural or man-made, can affect the characteristics of a waterbody.

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