328 



of the gross effects of oil, they have been unable to answer important basic ques- 

 tions on the effect of i>ollutant hydrocarbons in the marine environment. 



Data gathered from on-site surveys of an oil spill, while descriptive of the 

 effects of that spill, must be applied to other situations with caution. Straughan 

 (1969, p. .369) reporting on investigations of the Santa Barbara oil spill noted 

 factors unique to that incident: (1) the long history of natural oil seepage in 

 the Santa Barbara Channel, and (2) unusually heavy winter-run-off at the time 

 of the spill which reduced salinities, increased .sedimentation, and increased 

 DDT in the channel. R. L. Kolpack (Personal communication cited in Kanter, 

 et al. 1970, p. 487) noted that Santa Barbara crude oil is relatively insoluble 

 in seawater and contains a very low percentage of light aromatic compounds. 

 Thus, information gathered on the effects of the Santa Barbara spill are of lim- 

 ited utility in predicting the ecological effects of spills of other oils in other areas. 



Lewis (1970, p. 6) commenting on approaches to the study of chronic pollu- 

 tion contends "... that without a massive expansion of ecological and reproduc- 

 tive data by simultaneous multi-disciplinary studies not only will we be unable 

 to detect the significant long-term changes, but we will even remain unaware 

 of the most suitable or important species and methods to build into a monitoring 

 program." He notes our general lack of understanding of community structure 

 and population dynamics which severely limits the interpretation of data and 

 our predictive ability. 



Copeland (1970, p. 831), discussing the response of ecological .systems to stress, 

 suggests the principle that ". . . these systems already subjected to energy re- 

 quiring stresses, are more likely to resist the changes than these (such as tropical 

 systems) ad?ipted to relatively constant environments." He concludes that estu- 

 arine ecosystems composed of organisms capable of wide adaptations and general- 

 izations, such as north temperate systems, would be relatively unaffected by 

 the same magnitude of disturbance that would drastically alter a tropical sys- 

 tem. Odum (1970, p. 840) notes, however, that many estuarine species are living 

 near the limit of their tolerance range and that any alteration in the environ- 

 ment, such as additional stresses caused by low levels of pollution or by de- 

 creased oxygen concentrations, could exclude these animals permanently from 

 the estuary. 



Studies of the effects of chronic low-level pollution upon subadult, larval and 

 egg stages and the causes for changes in sur^^val are extremely limited. Simply 

 measuring plankton volume or counting species to evaluate the impact of an 

 oil spill may not detect the physiological effects. Holmes (1969, p. 26) commenting 

 upon his own observations that phytoplankton abundance and species composi- 

 tion were not much changed following the Santa Barbara oil spill noted. " * * * 

 the effects of oil pollution upon the phytoplankton cannot be detected with the 

 methods employed." Natural fluctuations of both vertebrate and invertebrate 

 population levels often are such that qualitative or crude quantitative observa- 

 tions of a biological community might only reveal normal conditions unless a very 

 large change was observed to correlate with the spill. 



Because petroleum and petroleum products are toxic chemicals, to understand 

 the action of these pollutants it is essential to utilize the resources of biochemis- 

 try and biophysics (Blunier, 1970. tl 13: FAO, 1970). Chemical pollution of 

 the tissues of organisms can be detected by advanced analytic methods such as 

 are employed by Blumer, Souza. and Sass (1970), and this work is opening hew 

 vLstas of understanding of the effect of oil. The work of these latter authors 

 suggests that the consequences of iwllutant hydrocarbons in marine ecosystems 

 is as yet not understood. 



Blumer's (1969, p. 10) studies on the fate of organic compounds in the marine 

 food chain found that hydrocarbons, once they are incori>orated into a particu- 

 lar marine organism, are stable, regardless of their .'Structure, and that they may 

 pass through many members of the marine food chain without alteration and 

 may actually be concentrated in tissue. This is a situation similar to the chlori- 

 nated hydrocarbon group of pesticides, which concentrate in the marine food 

 chain to the point where toxic levels are reached. 



The entrance of oil-derived hydrocarbons into marine food chains is evident. 

 Smith (1968, p. 49) reported that the presence of oil and benzene-ring comi>ounds 

 in the feces of limpets browsing on an oily deposit has been demonstrate<l chem- 

 ically ; similar observations have been made on top-shells, Mnnodnntu. and 

 limpets. Patella, living on oily rooks at Perranuthnne. He rei>orted, "the propor- 

 tion of oil in material ingested by these animals was estimated as about 2t^30 

 percent in Patella and .>-50 i^ercent in Mnnodontn." Smith (1908, n. 0.">) believed 

 it unlikely that any food value to the browser is derived from such feeding ac- 



