Beam attenuation and chlorophyll concentration as alternative optical indices of phytoplankton biomass

Chlorophyll has long functioned as the prominent field metric for phytoplankton biomass, but its variability can be strongly influenced by physiological shifts in intracellular pigmentation in response to changing growth conditions. Hence an alternative measure of phytoplankton carbon biomass is needed that is insensitive to intracellular changes in pigmentation. The most likely optical candidate to fulfill this requirement is the particular beam attenuation coefficient [c.sub.p].