Light absorption and size scaling of light-limited metabolism in marine diatoms
Zoe Vanessa Finkel
Limnol. Oceanogr., 46(1), 2001, 86–94

Previous studies have found that the size-scaling exponent of metabolic rates in unicellular algae often deviates from the exponent of -1/4 usually found for heterotrophs. This study confirms a significant linear relationship between log cell volume (mm³) and log intrinsic growth rate (h^-1), carbon-normalized photosynthetic capacity and performance (h^-1), and carbon-normalized respiratory rate (h^-1) for eight marine centric diatoms under nutrient-saturated, light-limited conditions. The intrinsic growth rate and carbon-normalized respiratory rate have size-scaling exponents not significantly different from -1/4, whereas the carbon-specific photosynthetic rates deviate from -1/4. The size dependence of the optical absorption cross section (m² mg chlorophyll a^-1) due to the package effect provides a mechanistic model that explains the anomalous size scaling of the anabolic rates of unicellular phytoplankton.