The carbon and chlorophyll content of phytoplankton from various nutrient regimes

We have measured the relationship between chlorophyll and carbonin phytoplankton cultures and natural populations of phytoplanktonusing simple standard extraction procedures without correctionfor degradation products. During exponential growth of fourcultures of unicellular and colonial green algae and one diatom,chlorophyll varied from 1.22 to 6.08% of the phytoplankton carboncontent (=3.03%). The chlorophyll content of the cultures was lower during nitrogen and phosphorus deficiency.Results from natural populations of phytoplankton from eutrophiclakes and from a coastal marine station gave values mostly rangingfrom 1.5 to 3.7% chlorophyll, corresponding to carbon/chlorophyllratios of 27–67. If only a rough estimate of the phytoplanktoncarbon biomass is required, a simple, efficient extraction procedurecan be used without any corrections for degradation products.