26 



Whites Point. The maximum increase is at Hyperion where 

 ammonia-nitrogen was concentrated 170 times over normal, 

 3,000 feet from the outfall at the surface. 



In Table III the enrichment of the surface water at 1,000 

 foot intervals from the outfall was made from the average 

 values of the nutrients on both days of sampling and on both 

 sides of the boil. Since factors are computed from the 

 averages, the decrease with distance appears small. 



PLANKTON NEAR THE (XIEAN OUTFALLS 



On all cruises for bacterial studies, plankton casts 

 were made at each hydrographic station. The waters surrounding 

 the Orange Cotmty and Los Angeles County outfalls were rela- 

 tively free of plankton prior to December 19, 1955. Average 

 volumes recovered were less than 0.5 ml, and there was no 

 increase in the area of the sewage boil. None of these 

 samples was retained, but the volume was noted at each station. 



On December 19 and 20, 1955, near the Orange County out- 

 fall, the volume of plankton in each haul was markedly greater 

 than earlier in the year. Many recoveries contained 10-14 

 times the earlier volume of plankton and at 3 stations the 

 volume was 30 times greater. The most abundant organisms were 

 diatoms (53% average) and dinof lagellates (31% average). With- 

 in the diatom group, Chaetoceros sp« was most numerous followed 

 closely by Ditylum sp. and Coscinodiscus sp. Of the dino- 

 f lagellates, Ceratium furca was the most common and Ceratitm 

 tripos the next, Zooplankton average 14% of each haul and were 

 mainly nauplius larvae (Table IV). 



