Etude de la fertilité des eaux marines au moyen de tests biologiques effectués avec des cultures d'algues. IV. Etude d'eaux cǒtières méditerranéennes

Abstract

Several aspects of sea water enrichments were previously studied and the method for growth-potential measurements was improved. The experiments presently reported were carried out in order to estimate the validity of the method. Natural sea water was used from two different marine areas. Eleven enrichments are added to the samples; their concentrations are those of the ASP 2 solution of PROVASOLI et al. (1957); one, two or three of the components are missing. Chaetoceros lauderi, Phaeodactylum tricornutum and Skeletonema costatum are used as test organisms.

The data clearly indicate that the information obtained from sea water enrichments can be different from those given by the usual analysis of chemical nutrients. For the same chemical substances missing, there is a striking discrepancy between the results obtained from different test strains. On the contrary, within the array of sea water samples, the same enrichments are always growth-promoting or growth-inhibiting for each of the three organisms.