Factorial Productivity Experiments in a Shallow Estuary: Energetics of Individual Plankton Species in Mixed Populations

A nonlinear programming method is described for estimating productivity parameters of individual plankton populations from data on mixed species water samples. The method is flexible in yielding average values over a treatment set established by experimental design. Specimen data on in situ populations of Skeletonema costatum are examined for illustration. Changes in estimated energy-processing characteristics of this diatom during a summer succession in the York River, Virginia, indicated a wide range of physiological states available to the species. Computed values of its gross production and respiration were correlated positively, but estimates of its productive output per individual were related inversely to corresponding values for other species. Various usages of the technique are discussed.