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Figure 11. — Skidaway Institution of Ocean- 

 ography innercontinental shelf system 

 components. 



—^\f\f\ » LOSS FROM SYSTEM 



the air at La Jolla, Calif., the quantities of CHCs introduced 

 into the system can be adjusted. 



To measure such low levels of CHC in 1 -liter quantities of 

 seawater it was necessary to develop a sensitive method for 

 detecting CHC residues. Currently, CHC transfer is being meas- 

 ured in a simple marine food chain: seawater medium -^ algae 

 -^ rotifers -> anchovy larvae. Twenty-liter cultures of the green 

 flagellate, Diinaliella, and the dinoflagellate, Gymnodinium 

 splendens, are monitored at 5-day intervals to determine the 

 accumulation of CHCs during exponential growth. Rotifers, 

 Brachionus plicatilis, maintained in 20-liter Diinaliella cultures 

 are also tested for CHC residues every 5 days. 



Anchovy larvae, Engraulis mordax, reared on the algae roti- 

 fier diet are sampled every 5th day for 20 days. To separate the 

 larger rotifiers from the flagellates, the TOtiier-Dunaliella cultures 

 are passed through 35 micron screening. 



Dunaliella is isolated from the culture media by continuous 

 flow centrifugation. All tissue samples are prepared for gas- 

 chromatographic analysis. 



To get an idea of what might be happening still further up 

 the food chain in nature, samples of porpoise and tuna livers 

 were analyzed for CHCs. These samples were obtained by 

 NOAA's National Marine Fisheries Service porpoise observers 



aboard commercial tuna boats far from any source of CHCs 

 (e.g., Los Angeles, Calif.). Analyses were made to compare 

 biological magnification of CHCs by tunas and porpoise, both 

 presumably feeding on the same forage. 



In the future, Lasker intends to make a more detailed 

 investigation of the simple, algae -^ rotifiers -» anchovy larvae 

 food chain. After accurately determining concentration factors, 

 studies will be made on rates of exchange and losses of CHCs in 

 this food chain as well as in more complicated food chains 

 involving adult anchovies and predatory fishes. 



Organization: University of Georgia, Skidaway Institute of 

 of Oceanography 



Investigator: H. Windom 



Project Title: The Transfer of Heavy Metals Through the 

 Inner Continental Shelf to the Open Ocean 



Grant No.: GX-33615 



The Skidaway Institute of Oceanography has made consid- 

 erable progress on both the field assessment and laboratory 

 aspects of this Environmental Quality Program project, the pur- 

 pose of which is to study the transfer of heavy metals through 

 an inner Continental Shelf system to the open ocean (fig. 10). 



10 



