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Limnology and Oceanography
Volume 22, Issue 2 pp. 361-369
Article
Free Access

A trophic state index for lakes1

Robert E. Carlson, 

Corresponding Author

Robert E. Carlson

Limnological Research Center, University of Minnesota, Minneapolis 55455

Present address:DepartmentofBiological Sciences, Kent State University, Kent, Ohio 44242.Search for more papers by this author
First published: March 1977
https://doi.org/10.4319/lo.1977.22.2.0361
Citations: 2,732
†
Contribution 141 from the Limnological Research Center, University of Minnesota. This work was supported in part by Environmental Protection Agency training grant U910028.

Abstract

A numerical trophic state index for lakes has been developed that incorporates most lakes in a scale of 0 to 100. Each major division (10, 20, 30, etc.) represents a doubling in algal biomass. The index number can be calculated from any of several parameters, including Secchi disk transparency, chlorophyll, and total phosphorus.