| Abstract: | Measurement of the depth-mean PAR (photosynthetically active radiation) extinction coefficient, ° Ko, is important in the study of estuarine productivity. Measurements of ° Ko, beam attenuation coefficient and Secchi disc depth are presented for the turbid waters of the Tamar Estuary. Equations are formulated which allow good estimates of ° Ko to be determined both from the beam attenuation coefficient (at 660 nm) and from the Secchi disc depth. For comparison, similar data are presented for the clearer waters of the northeast Atlantic. |
