Quantitative degradation of chlorophyll by a marine herbivore1

In laboratory grazing experiments, primarily with Calanus sp. feeding on Coscinodiscus angstii, the decrease in chlorophyll concentration and the increase in pheophorbide concentration was determined. The average conversion of chlorophyll to pheophorbide was 66% on a weight basis and 100% on a molar basis. Some chlorophyll was found in fecal pellets. The specific absorption coefficient of pheophorbide in 90% acetone at 667 nm was 53.5 (g-cm)−1, about the same as that of pheophytin under the same conditions. Previously published equations for the determination of pheophytin can be used for pheophorbide.