CHARACTERIZATION OF SURFACE-ACTIVE SUBSTANCES DURING A SEMIFIELD EXPERIMENT ON A PHYTOPLANKTON BLOOM

The determination of surface-active substances (SAS) during the evolution of a phytoplankton bloom in a model plankton ecosystem was done by electrochemical methods. The separation and characterization of the organic material present were also done on XAD-8 resin columns. It was found that large amounts of the SAS, predominantly of the humic (fulvic) type, were present from the beginning of the experiment and partly masked the effects of organic substances released by phytoplankton. Although the transformation of the organic matter (consumption and/or excretion) was obvious, no general trend in the amount or type of surface-active matter was observed during the experiment. © 1990.