Biochemical Studies 



Biochemical studies concentrate on the ef- 

 fect of pollutants on bacteria and key enzymes 

 and enzyme systems. If successful the tech- 

 niques used to study the effects of petroleum 

 compounds on the rates of reaction of these 

 enzymes in a cell-free assay could be extended 

 to other pollutants. 



Table 2 

 BIOLOGICAL EFFECTS PROGRAM 



Contaminant 



Halo- 

 genated 



hydro- 

 carbons 



Petro- Trace 

 leum metals 



Biological Material Number of Projects 



Cell-free enzymes — 



Bacteria 1 



Phytoplankton 2 



Zooplankton 1 



Higher organisms 2 * 

 Communities 



1 

 1 

 1 

 2 

 project being 

 reviewed 



* Pilot study of biological effects of phthalates in one 

 project 



Whole Organism Studies 



The effects of pollutants on photosynthetic 

 microalgae will be determined by measure- 

 ments of growth, respiration and photosyn- 

 thetic rates. If severe effects are observed, 

 morphological changes will be sought using 

 light and electron microscopy. Both pure and 

 mixed cultures will be used in these studies. 

 The short generation time of microalgae 

 makes them well suited for short-term experi- 

 ments. 



In the case of zooplankton and higher or- 

 ganisms, a much longer generation time dic- 

 tates that biological parameters other than 

 growth and reproductive rates must be used 

 to measure pollutant effects. Metabolic rate, 

 determined by oxygen consumption, is being 

 used with animals at several trophic levels. 

 Other parameters being investigated include 

 filtering and ventilation rates, lethal tempera- 

 ture limits, simple behavior and genetic struc- 

 ture changes as measured by electrophoresis 

 of protein molecules. 



Community Studies 



The community studies require living sys- 

 tems that are less than complete compared to 

 natural ecosystems but which are still enough 

 like the natural system to provide valid an- 

 swers about pollutant effects. Research on 

 the effects of chemical pollutants on ocean 

 ecosystems is being carried out by scientists 

 from several U.S. and Canadian institutions 

 in the Controlled Ecosystem Pollution Experi- 

 ment [CEPEX). 



In this project natural marine communities 

 are maintained in large, flexible plastic cylin- 

 ders which are open to the atmosphere and 

 closed at the bottom (Figure 1). In the ex- 

 periment the contents of one enclosure are 

 altered by adding chemical pollutants while 

 a second functions as a control. The response 

 of specific trophic levels to the chemical per- 

 turbations will be assessed and the changes 

 compared to those taking place in the control 

 enclosures which are maintained under con- 

 ditions as close as possible to the natural 

 environment. These experiments are inter- 

 disciplinary, requiring cooperative research 



Figure 1 



