AN EMPIRICAL-MODEL OF THE PHYTOPLANKTON CHLOROPHYLL-CARBON RATIO - THE CONVERSION FACTOR BETWEEN PRODUCTIVITY AND GROWTH-RATE

We present an empirical model that describes the ratio of phytoplankto n chlorophyll a to carbon, Chl: C, as a function of temperature, daily irradiance, and nutrient-limited growth rate. Our model is based on 2 19 published measurements of algal cultures exposed to light-limited o r nutrient-limited growth conditions. We illustrate an approach for us ing this estimator of Chl:C to calculate phytoplankton population grow th rate from measured primary productivity. This adaptive Chl:C model gives rise to interactive light-nutrient effects in which growth effic iency increases with nutrient availability under low-light conditions. One implication of this interaction is the enhancement of phytoplankt on growth efficiency, in addition to enhancement of biomass yield, as a response to eutrophication.