Day‐to‐day variations in the spring‐summer photosynthetic parameters of coastal marine phytoplankton

Abstract

The day‐to‐day variations over a 70‐day period in the parameters describing the light‐saturation curve of natural assemblages of coastal marine phytoplankton were examined and related to changing environmental conditions. The initial slope, α^B, and the light‐saturated rate, P_m^B, both showed a threefold variation. Correlation and regression analysis attributed most of the variation in α^B and P_m^B to factors relating to community structure. Changes in community structure resulting from the normal progression of spring‐summer conditions were interrupted periodically by transient physical phenomena (passage of storms, periods of up‐welling, etc.). The importance of physical transients to the short term dynamics of the phytoplankton production system places severe constraints on the development of predictive models of phytoplankton production.