536 



Marine Microbiology 



AEROBIC 

 TOTAL 

 S E, COLI 

 E3 ENTEROCOCC 



ANAEROBIC 

 TOTAL 



Fig. 1. 



(17). These observations were confirmed by a second field study 

 during which the alga was identified as Phaeocystis pouchetii and 

 algal concentrates were collected for laboratory studies (24). 



The antibiotic principle of Phaeocystis pouchetti was found 

 to be a volatile acid which was isolated as the sodium salt (20) 

 and later identified chemically, physically and biologically as 

 acrylic acid, CH.. = CH-COOH (21). The effect of synthetic 

 sodium acrylate on the coliform flora of chicks is shown in 

 Figure 2. The acrylate level of 0.1 per cent which approximates 

 that estimated to be naturally ingested by penguins had a marked 

 effect on the suppression of Escherichia coli. Further antibiotic 

 properties of acrylic acid have been studied in vitro and in \ i\ o 

 (23). 



