Bacteria isolated from surface sea waters, brackish waters and from algal cultures were classified in nutritional clusters. Results obtained with an hierarchical method were improved by using the correspondence analysis. The former main statements appear confirmed and new informations are pointed out, mainly concerning the organic compounds which are the best indexes of the nutritional characteristics; e. g. a few organic acids and amino-acids can be used to estimate the versatility of bacteria; it also appears that strains which preferentially assimilate substrates of one chemical group, do not easily attack substances of other groups.
