In other experiments, microorganisms that were known not 

 to metabolize hydrocarbons showed a bioconcentration of these 

 hydrocarbons from the dissolved phase in seawater of about 

 2,000-fold, based on cell weight. 



Fluorescence microscopy showed that most of the bioconcen- 

 trated hydrocarbons were located in the cell mitochondria, with 

 some in the cell cytoplasmic membrane. Continuous culture 



populations of algae were sensitive to saturating concentrations 

 of chlorinated biphenyl. Sensitivity was significantly greater 

 when the algae were paired with the yeast, Rhodotorula rubra, 

 a marine isolate. As shown in figure 7, 2 micromolar dichloro- 

 biphenyl caused dramatic changes in the algal population dis- 

 tribution and limited nutrient content. 



Continuous culture systems were also sensitive to solvents 



TIME, DAYS 



Figure 7. — Dichlorobiphenyl addition to a gnotobiotic continuous culture at steady state. On day 6, small inocula of Selenastrum 

 capricornutum (algae) were added to the carbon-limited continuous cultures of Rhodotorula rubra. The concentration 

 of phosphate in solution reflects phosphate-limitation of the algae. On day 43, when the system was at steady state, 

 approximately 2 micromolar 2,4' dichlorobiphenyl (DCB) was added to the dual culture system. The culture dry weight 

 and total cell numbers decreased, while phosphate in solution increased until less than approximately 0.2 micromolar 

 dichlorobiphenyl remained in the culture vessel. The yeast viable counts oscillated slightly immediately after the ad - 

 dition, but soon returned to normal. Dilution rate (growth rate) = 0.36 day'. Residence time of culture vessel"con - 



tents = 2.78 days. dry weight of yeast + algae, x x phosphate in solution. A A total cell count of 



yeast + algae. • • viable cell count of yeast. 



10 



