Attenuation measurements of monochromatic light in marine-sediments

The attenuation coefficients of monochromatic irradiances of wavelengths between 400 and 730 nm were determined for four different types of natural marine sediments. The attenuation coefficients were highly dependent on wavelength and type of sediment, the longest wavelengths penetrating deepest into ali four sediments. At 550 nm attenuation coefficients of 1. 9 mm 1 for sand and 12.2 mm 1 for mud were obtained, corresponding to one per cent irradiance depths of 2.40 and 0. 38 mm, respective! y. The attenuation coefficients showed linear correlation with the concentrations of organic matter and phaeopigrnents, and less signiftcant exponential correlation with the median grain size and the concentration of silt.