What is Carlson's Trophic State Index or TSI?
Carlson’s Trophic State Index (TSI) is a common method for characterizing a lake’s trophic state or overall health. The method uses Secchi, chlorophyll-a, and phosphorus measurements. Trophic status refers to the level of productivity in a lake as measured by phosphorous content, algae abundance, and depth of light penetration.
TSI < 30 - Oligotrophy: Clear water, oxygen throughout the year in the hypolimnion
TSI 30 - 40 - A lake will still exhibit oligotrophy, but some shallower lakes will become anoxic during the summer
TSI 40 - 50 - Water moderately clear, but increasing probability of anoxia during the summer
TSI 50 - 60 - Lower boundary of classical eutrophy: Decreased transparency, warm-water fisheries only
TSI 60 - 70 - Dominance of blue-green algae, algal scum probable, extensive macrophyte problems
TSI 70 - 80 - Heavy algal blooms possible throughout the summer, often hypereutrophic
TSI > 80 - Algal scum, summer fish kills, few macrophytes
May 23, 2007 9:52 AM | Category: Technology