Phytoplankton populations in the coastal waters of the Antarctic Peninsula appeared, on the basis of chlorophyll- specific vertical attenuation coefficients measured at wavelengths through the photosynthetic spectrum, to have a markedly greater package effect than populations from temperate oceans: Mitchell and Holm-Hansen (1991a) attributed this to the presence of larger cells with high cellular pigment concentration resulting from chronic low-light adaptation in nutrient-rich waters.