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An analysis was performed with multivariate statistical methods of the relationship between chlorophyll a concentrations and eighteen physico-chemical parameters measured over a six year period in four eutrophic Nebraska reservoirs . In the reservoirs with relatively clear water early in the growing season, physical factors (Secchi depth, turbidity, temperature) and non-nutrient chemical factors (alkalinity, hardness, C .O. D .) were significantly related to chlorophyll a concentrations, but macronutrients (nitrogen and phosphorus) were not . In the reservoir with persistent abiogenic turbidity, chemical factors including nitrogen and phosphorus were significant but physical factors were not . Six models based upon intercorrelations between measured parameters and chlorophyll a are evaluated for their usefulness in accounting for chlorophyll a variance. The best model accounts for 67 -70 percent of the total variation in chlorophyll a in the four reservoirs .

This paper describes a new open chamber technique for measuring CO2 evolution from soil in situ, which minimizes measurement errors due to soil disturbance and chamber effects. An analysis of the data collected by this new technique, and a reanalysis of data already published, shows that there is clearly a relationship between the metabolic activity of a soil and the velocity of wind passing over that soil. The mechanism and implications of this relationship are discussed.

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