Abstract
The penetration of natural light into a vertically mixed reservoir in the Thames Valley was compared with particle distribution as determined by a Coulter Counter. Attenuation coefficients determined using blue, green, yellow and red filters were correlated with Total Particulate Volume and Total Particulate Surface Area. While there was a low but acceptable correlation of light attenuation with Total Particulate Volume, there was a high correlation of light attenuation with Total Particulate Surface area. Theoretical aspects of this correlation are discussed with reference to the moderate production of phytoplankton in vertically mixed reservoirs of the Thames Valley. The Coulter Counter can give absolute measures of turbidity resulting from suspended particles of a diameter exceeding 3 µm.
Keywords