2 ^ 6 8 10 12 U 16 18 20 22 lU 



Time(min) 



Figure 2. Effect of water solubles from No. 2 fuel oil on photosynthesis of 3 micro- 

 algae: Thalassiosira pseudonana (3H), Agmenellum quadruplicatum (PR-6). and 

 Chlorella auiotrophica (580). Conditions: No. 2 fuel oil equilibrated for 24th stirring 

 with filtered seawater; seawater separated and filtered through 0.45 iim Millipore 

 filter and added to algal suspension 8 min before light turned on. Concentration of 

 this water soluble fraction is given in percent, v/v (e.g. 12.5% = 1.4 ml of algal sus- 

 pension plus 0.2 ml of seawater-oil solubles) . Controls: seawater plus medium 

 ASP-2. Algal strains are identified in Table 2. The algal concentrations for PR-6, 

 3H and for 580 are appro.ximately 1 X 10' cells/ml in medium ASP-2. Electrode 

 current at air saturation, medium ASP-2 = 3.4 fia. Light intensity, limited by 

 Baird-Atomic Hot Mirror (34-01-2) to 350 to 800 nm, was 580 mW/cm^ at level of 

 electrode chamber, measurement temperature 30°C. 



With both the sea water equilibrated with fuel oil and the crude 

 oils, the toxic activity is mainly localized in medium and higher boil- 

 ing fractions derived from distillation cuts from these materials. 



The question of the toxicity of fuel oils to the microalgae has been 

 examined in greater detail. Four fuel oil samples were obtained from 

 Exxon Corporation. Approximately 50% of the compounds in the 

 water solubles from these four fuel oils have been identified via gas 

 chromatography and mass spectrometry. In addition to the well de- 

 scribed types of compounds (naphthalenes and benzenes) expected 

 in water soluable extracts phenols, anilines, and indoles were found 



16 



