Regional variability among nonlinear chlorophyll-phosphorus relationships in lakes

Limnology and Oceanography
By: , and 



The relationship between chlorophyll a (Chl a) and total phosphorus (TP) is a fundamental relationship in lakes that reflects multiple aspects of ecosystem function and is also used in the regulation and management of inland waters. The exact form of this relationship has substantial implications on its meaning and its use. We assembled a spatially extensive data set to examine whether nonlinear models are a better fit for Chl a—TP relationships than traditional log-linear models, whether there were regional differences in the form of the relationships, and, if so, which regional factors were related to these differences. We analyzed a data set from 2105 temperate lakes across 35 ecoregions by fitting and comparing two different nonlinear models and one log-linear model. The two nonlinear models fit the data better than the log-linear model. In addition, the parameters for the best-fitting model varied among regions: the maximum and lower Chl aasymptotes were positively and negatively related to percent regional pasture land use, respectively, and the rate at which chlorophyll increased with TP was negatively related to percent regional wetland cover. Lakes in regions with more pasture fields had higher maximum chlorophyll concentrations at high TP concentrations but lower minimum chlorophyll concentrations at low TP concentrations. Lakes in regions with less wetland cover showed a steeper Chl a—TP relationship than wetland-rich regions. Interpretation of Chl a—TP relationships depends on regional differences, and theory and management based on a monolithic relationship may be inaccurate.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Regional variability among nonlinear chlorophyll-phosphorus relationships in lakes
Series title Limnology and Oceanography
DOI 10.4319/lo.2014.59.5.1691
Volume 59
Issue 5
Year Published 2014
Language English
Publisher ASLO
Contributing office(s) Coop Res Unit Leetown
Description 12 p.
First page 1691
Last page 1703
Country United States
State Iowa, Maine, Michigan, New Hampshire, Ohio, Wisconsin
Online Only (Y/N) N
Additional Online Files (Y/N) N
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