Compaction of the sediment in the core, however, was not uniform; the 

 sediment near the core's surface contained much more water than the 

 older, deeper sediments. By measuring the volume of water in succes- 

 sive layers of cores frozen immediately after collection, a correction 

 was made for the changes in sediment density and a theoretical sedimen- 

 tation rate calculated. This deposition rate was compared to sediment 

 accumulated monthly in glass jars at the harbor stations and to coarse 

 sand deposits in the sediment caused by dated dredging and filling 

 activities. 



A layer of coarse sand 5.25 inches (13.33cm) below the existing surface 

 of the sediment near the desalination plant corresponded well to the 

 calculated depth of sediment that should have deposited since the 

 desalination plant sea wall was constructed in 1967. 



BIOLOGICAL INVESTIGATIONS 



Two approaches were used in the design of the biological work. The 

 major emphasis of the biological program was in situ investigations 

 of the effects of the desalination plant effluent. Laboratory bio- 

 assays were conducted to isolate the more toxic features of the 

 effluent, but were strictly an aid to interpreting the in situ data. 



The harbor itself formed the basis for a large scale toxicological 

 study. Three lines of investigation were used to take advantage of 

 this opportunity; data were collected from selected quadrats and 

 transects, new surfaces for the settlement of diatoms and larger 

 organisms were examined, and selected organisms were transplanted to 

 sites where effects of the discharge on individual specimens could 

 be followed. 



QUADRAT AND BIOMASS SAMPLES 



One-meter square quadrats were roped off at each of the twenty stations. 

 To achieve comparable data, the stations were set on the vertical cal- 

 carinite walls of the canal area; one quadrat near the top of the wall 

 and one near the bottom. Divers recorded the organisms present in each 

 quadrat once a month. Near these quadrats divers took monthly 0.1m 

 samples of the substrate for biomass analysis. Species found at each 

 of the stations were tabulated both from quadrat and biomass collections, 



Diversity was calculated using Margalef's proposed index (Margalef 

 1957). This index was selected since the mathematical weighting of 

 the sample is related to the concept of entropy in the third law of 

 thermodynamics. It satisfactorily accounts for species present and 



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