THE CONCEPT OF ENERGY EFFICIENCY IN PRIMARY PRODUCTION 1

The use of efficiency factors in primary productivity studies is discussed. A coefficient k b is defined which measures the contribution of photosynthetic processes to the total optical attenuation coefficient. It is shown that to a first order approximation, k b at any depth is given by the ratio of the primary production to the incident radiation at that depth, when both are expressed in calories. Values of k b are calculated for two stations in St. Margaret’s Bay, Nova Scotia. At any depth, k b depends linearly on the chlorophyll concentration at that depth. Errors involved in measuring k b are discussed and suggestions made for increasing precision. It is suggested that k b could be used as an index to compare the primary productivity of waters and that the regression of k b on the chlorophyll concentration could be used as a predictive tool in primary production research.