enough to raise the average weight by almost 2 

 mg/m^. The large standard deviation is indicative 

 of the large spread in observed valves. By contrast, 

 the average concentration for the 5° x 5° grid that 

 OWS Hotel is located in was only 1.172 mg/^ with 

 a standard deviation of ±0.235. These latter 

 numbers were arrived at by excluding the OWS 

 Hotel data. 



A final observation to be made at OWS Hotel 

 was that the tarball concentration did vary 

 seasonally. It was lowest in the winter season and 

 generally highest in the summer, although the tar- 

 ball concentration can be large in the fall or spring 

 as well. The winter season at OWS Hotel was 

 usually the period with highest sea state and the 

 greatest winds which would induce mixing of the 

 surface waters to greater depths. This would tend 

 to make values from samples collected during this 

 period lower than in periods of smaller seas and 

 lesser winds. 



CONCLUSIONS AND RECOMMENDATIONS 



In general, low tarball concentrations were 

 found in the polar regions. This can probably be 

 attributed to the limited amount of man's activities 

 and fewer number of natural seeps in these areas. 

 Certainly these would be areas that would require 

 watching over the next several years. 



Areas of the heaviest tarball concentration 

 appear to be in areas of high commercial traffic, 

 although high traffic areas generally coincide with 

 areas where extensive drilling is taking place, so 

 caution must be used when drawing conclusions. 

 Areas along both the east coast and west coast of 

 the United States fall into this category. 



Due to the crude nature of sampling for tarballs, 

 the data presented is only representative of the 

 tarball concentration in the region. The more tows 

 that are taken, the more confidence that can be put 

 on the numbers associated with the concentration. 



There are improvements which might be made 

 with the sampling techniques. High tarball concen- 

 trations have been found in wind rows (Langmuir 

 cells) and if the sampling happens to be done 

 between wind rows as opposed to along or across 

 wind rows, the results would be expected to differ 

 considerably. One possible solution to help 

 eliminate this bias would be to sample in a trackline 

 perpendicular to the wind. This would tend to cut 

 across wind rows giving a more representative 

 sample. 



More emphasis should also be given to describing 

 the hardness, texture, color, and sizes of the tar- 

 balls collected. When stored in jars, the tarballs 

 tend to lose their identity. These better descrip- 

 tions would give some insight into the age and 

 possibly source of the tarballs. 



There are still areas in the middle of the Gulf of 

 Mexico that have not been sampled under this pro- 

 gram. Special attention would have to be given to 

 the water mass being sampled during the tow to 

 determine whether the collected samples 

 originated in the Gulf of Mexico or are being 

 carried through by the Loop Current. 



There have been a fair number of tows taken in 

 the Gulf of Alaska, an area that bears future 

 watching. An increase in the tarball concentration 

 in this area could be indicative of the increase in 

 petroleum transportation and the need for stricter 

 guidelines and/ or enforcement of pollution regula- 

 tions. Similarly, continued monitoring of the polar 

 regions in the western North Atlantic Ocean is 

 necessary to evaluate the fate of that region. 



Finally, emphasis should be put on sampling in 

 those areas where there is little or no information 

 now available. The chemical analysis of tarballs 

 would give some insight into the origins and 

 possibly age of the tarballs by looking at the 

 hydrocarbon fractions and trace elements. 

 However, due to the large number of samples 

 collected and the expense involved in the analysis, 

 only selected samples could be analyzed. Only 

 through diligence can changes in concentration be 

 detected and this is necessary if we are to deter- 

 mine whether the control measures presently 

 employed are adequate. 



REFERENCES 



Butler, J. N., B. F. Morris, and J. Sass (1973). Pelagic Tar from 

 Bermuda and the Sargasso Sea, Bermuda Biological Station 

 for Research, Special Report No. 10, 346 pp. 



Butler, J. N. (1975). Pelagic Tar, Scientific American, 232, 

 No. 6, 90-97. 



Koons, C. B. and P. H. Monaghan (1976). Input of Hydrocar- 

 bons from Seeps and Recent Biogenic Sources. Sources, 

 Effects, and Sinks of Hydrocarbons in the Aquatic Environ- 

 ment, American Institute of Biological Sciences, pp. 84-107. 

 National Academy of Sciences (1975). 



National Academy of Sciences (1975). Petroleum in the Marine 

 Environment, National Academy of Sciences, 107 pp. 



