waters, the Gulf of Alaska can serve as an ideal 

 laboratory to accurately monitor the effect of oil 

 transport through this region. 



The Bering Sea had an even lower concentration 

 of tarballs than did the Gulf of Alaska. This may be 

 attributed to the few natural oil seeps along its 

 coastline and to the fact that ship traffic is nearly 

 nonexistent in this region. Twenty-three tows 

 were made in the Bering Sea and of these only one 

 tow recovered any tarballs. The concentration of 

 tarballs on that tow was .009 mg/m^. 



Throughout the North Pacific Ocean tarball con- 

 centrations in the various grid areas fluctuated 

 widely (Fig. 2) from 0.0 to 3.3 mg/m^. Few of the 

 areas, however, had more than five tows made 

 within their boundries. Those areas with high con- 

 centrations generally had one or two tows with 

 much larger values than the rest, and thus their 

 high averages may be due to anomalies. The 

 average concentration for the North Pacific Ocean 

 was about 1.25 mg/m^. Typically there were high 

 concentrations between the Hawaiian Islands and 

 the west coast of the United States which may be a 

 result of commercial traffic through this area. 



GULF OF MEXICO 



In the summer of 1975 and winter of 1976 the 

 USCGC ACUSHNET made oceanographic cruises 

 in the U.S. coastal waters of the Gulf of Mexico. 

 During each of these cruises, tarball surveys were 

 conducted at 44 and 45 locations respectively. This 

 gave a reasonably synoptic picture of the tarball 

 concentrations in these waters. 



The Gulf of Mexico was also found to have a 

 fairly high overall tarball concentration, about 1.45 

 mg/m^ (Fig. 3). It was not constant throughout the 

 Gulf but increased from east to west. Charles W. 

 Morgan (personal communication) showed that 

 this may have some correlation with offshore oil 

 drilling. Morgan also described how the currents of 

 the Gulf will tend to sweep material rapidly into 

 the area along the Texas coast and then let it 

 accumulate as the water slows down. Koons and 

 Monaghan (1976) indicate that the shelf area of the 

 southwestern area of the Gulf is a region of high 

 seepage potential which may account for many of 

 the tarballs throughout the Gulf. 



NORTH ATLANTIC OCEAN AND ADJACENT 

 AREAS 



The Labrador Sea is another region of very low 

 tarball concentration. The area along the north- 

 eastern coast of Nev^rfoundland was sampled by 3 



tows with an average tarball concentration of 

 <0.01 mg/m^ indicating a fairly stable condition. 

 Any increase in tarball concentration in this region 

 would tend to indicate that man-made oil spills or 

 dumping was responsible since this area is becom- 

 ing increasingly important in the search for oil. 



The North Atlantic Ocean was an area of 

 extreme fluctuation in tarball concentration from 

 one grid area to another (Fig. 4). Although some 

 areas were sampled very heavily, there was a large 

 area at midocean that was never sampled. From 

 the data which was taken, it may be concluded that 

 along the northern half of the U.S.'s eastern 

 seaboard the tarball concentration is higher than in 

 other observed areas of the North Atlantic perhaps 

 due to the tremendous amount of commercial traf- 

 fic, including tankers, through the area. The cur- 

 rents in this area tend to bring tarballs from other 

 regions to this area resulting in higher tarball con- 

 centrations. The average concentration for the 

 North Atlantic Ocean was about 1.65 mg/m^ 

 although some grid areas had concentrations of 

 greater than 8 mg/m^. 



OCEAN WEATHER STATION HOTEL 



The data for OWS Hotel, as previously mentioned, 

 were grouped by season. It was foimd that the tarball 

 concentration can vary tremendously over a 24 hour 

 span, even if two successive tows were made in the 

 same water mass. In one instance during November 

 1975, the observed tarball concentration went from 

 0.0 mg/m2 on the 25th to 320.7 mg/m2 on the 26th! 

 Sea state conditions, water temperature, etc., 

 remained constant over the period. 



One particular three week span, November 19th 

 to December 12th, 1975, had an average tarball 

 concentration three orders of magnitude over the 

 usual November/ December average. A system of 

 two warm-core eddies entered the region during 

 the time and may have carried the tarballs respon- 

 sible for this anomaly from the Sargasso area but 

 positive correlation is not possible. 



The relatively high average concentration of 

 7.996 mg/m^ and large standard deviation of 

 ± 45.475 may be a biased number due to the nature 

 of the operations on OWS Hotel. Basically the ship 

 remained in the area of a circle with a 15 nautical 

 mile radius while occupying OWS Hotel which 

 meant the ship was often drifting. It therefore may 

 well have been that the personnel conducting the 

 tows were looking for tarballs and made a con- 

 scious effort to collect tarballs. One tow had a con- 

 centration of 639.351 mg/m2 which in it self is 



