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Variability and Representativness of Lake Variables
Author(s) -
Håkanson Lars
Publication year - 1994
Publication title -
internationale revue der gesamten hydrobiologie und hydrographie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 0020-9309
DOI - 10.1002/iroh.19940790203
Subject(s) - alkalinity , seasonality , environmental science , sampling (signal processing) , spring (device) , physical geography , hydrology (agriculture) , geography , ecology , geology , biology , chemistry , physics , geotechnical engineering , organic chemistry , detector , optics , thermodynamics
This paper summarizes results from extensive field work in 95 Swedish lakes. It discusses four years (1986–1989) of monthly data on pH, Secchi depth, temperature, alkalinity, total‐P, conductivity, Fe, Ca, hardness and colour. These variables vary both temporally and areally. The focus here is on such variations and patterns in variations, and how to express lake‐typical values, not for specific sites and sampling occasions, but for entire lakes and longer periods of time (months‐years). This is of importance in monitoring and validating models. A definition of total variability (TV), expressing variability between adjacent months within the year, and between the same month for different years, is presented. Selected results: An important pattern emerges for total‐P with marked increases in TV during the summer and minimum values in winter. The pattern for colour shows lower TV during summer and higher TV during fall. The TV‐values for pH are low and stable thoughout the year and no clear seasonal pattern can be seen. A seasonal pattern exists for conductivity, alkalinity, hardness, and Ca with higher TV during spring. The results concerning the variability within and between lakes show that the greatest differences exist for conductivity and Fe; the smallest (except temperature) for pH and alkalinity.