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▲ LARGE-VOLUME STATIONS 

 A SMALL-VOLUME STATIONS 

 n STD STATIONS 



Figure 7. — Track of RV Melville, Pacific 

 GEOSECS Leg 6. 



classes of organisms. Field studies are integrated into the 

 Controlled Ecosystem Pollution Experiment (CEPEX). This 

 cooperative research project of international scope involves 

 trapping water and natural communities in large plastic en- 

 closures (10 m diameter by 30 m deep, or larger) and assessing 

 the effects of added pollutants on marine ecosystems — the long- 

 term effects influencing the stability of marine populations. 



Size of the CEPEX enclosure, or "bag," is based on the 

 volume of water and nutrients needed to support populations 

 at natural trophic levels for at least 30 days, and optimally for 

 100 days or more. The initial CEPEX enclosure is located in 

 Saanich Inlet, Vancouver Island, British Columbia (fig. 9). 

 This location was selected because of the following charac- 

 teristics: sheltered inlet has low current velocities; water depth 

 exceeds the depth of the eutrophic zone; biological produc- 

 tivity is relatively high; food webs are relatively simple; remote 

 location is far from sources of pollution; species composition 

 of plankton is as nearly typical of open ocean ecosystems as 

 possible; background data are available; and support facilities 

 are nearby. The general research plan is as follows: 



1) Identify modes by which organisms accumulate 

 pollutants from the environment; 



2) Determine relative rates of uptake, excretion, 

 and accumulation of pollutants at various trophic 

 levels; 



3) Identify first indications that metabolic functions 

 of specific groups of organisms have been altered. 



PUERTO RICO 



60 °W 



Figure 8. — Ship's track — RV Trident cruises 132, 

 134, and 137, for atmospheric particulate 

 collections. 



and determine what net effect of this alteration 

 may be; and 

 4) Identify species most susceptible to physiological 

 damage. 

 Four one-fourth scale model experimental containers were 

 constructed to permit engineering feasibility tests and to deter- 

 mine the response of biological systems following impoundment. 

 Based on limited experience with the one-fourth scale en- 

 closures. CEPEX participants believe the scientific objectives 

 can be accomplished by use of full-scale enclosures. 



Projects relating to biological effects studies and CEPEX 

 are listed in tables 3 and 4, respectively. A CEPEX project 

 summary follows. 



