Chapter V — 61 — Distribution in the Sea 



dant near land although some varieties such as sargassum, for example, 

 are not restricted to shallow waters. Also great rafts of sessile seaweeds 

 are sometimes dislodged and carried far to sea by storms and ocean cur- 

 rents. Gazert noted that the bacterial content of harbor water, which 

 was nearly always higher than that of the open ocean, was related to the 

 amount of terrigenous pollution in the region and was independent of the 

 water temperature. Not nearly as many bacteria were found in harbor 

 water at Simonstown, South Africa, as in Capetown harbor which receives 

 much more land drainage. 



Otto and Neumann (1904) observed the presence of thousands of bac- 

 teria per ml. of water near land and usually less than a hundred per ml. 

 in the Atlantic Ocean between Europe and Brazil. During a storm which 

 stirred up the bottom material, over 10,000 bacteria per ml. were found 

 in sea water. It is to be expected that turbulence which suspends bottom 

 deposits will increase the bacterial population of water because the bac- 

 terial population of bottom deposits is generally of the order of magnitude 

 of millions per ml. compared with hundreds per ml. for the overlying 

 water. 



At 20 stations in the open Atlantic 1 20 or more miles from land, Graf 

 (1909) found an average of 42 bacteria per ml. as compared with an aver- 

 age of 2000 bacteria per ml. at 12 stations less than 120 miles from land. 

 Using comparable procedures he found 54,000 bacteria per ml. of water 

 in the harbor of Lisbon, Portugal, and 15,000 per ml. in that of nearby 

 St. Vincent. 



In the South Seas, Lipman (1920) found only 10 bacteria per ml. of 

 water from stations exceeding four miles from shore whereas there were 

 as many as 400,000 bacteria per ml. in samples near the strand. In the 

 vicinity of Tutuila, Samoa Islands, Lipman found 1000 to 2000 bacteria 

 per ml. two or three miles from shore and 70,000 to 100,000 per ml. in 

 shallower water over Aua Reef. 



From his studies on the bacterial populations of the ocean in the 

 vicinity of Cape Cod, Massachusetts, Reuszer (1933) concluded that on 

 open, exposed shores receiving little land drainage, the effect of land on 

 the bacterial content of sea water appears to be negligible. Along open 

 shores, receiving considerable land drainage, any effect of the proximity 

 of land does not extend beyond about a mile from the open shore, but in 

 harbors receiving land drainage the number of bacteria may rise to very 

 high levels. 



Although more bacteria are nearly always found in coastal waters 

 than in the open ocean, the proximity to land per se is not responsible for 

 the larger bacterial populations. This is illustrated by the observations 

 of ZoBell and Feltham (1934) at the Scripps Institution of Ocean- 

 ography, which is strategically located beside the sea where there is virtu- 

 ally no land drainage except during the short rainy season, and the water 

 depth increases rapidly with distance from land. The chemical composi- 

 tion, including the organic content of the water near shore, is virtually the 

 same as that in the open ocean. During the dry season when the sea is 

 calm there is little difference in the bacterial population of the water with 

 distance from land, as illustrated by the data in Table XIII. 



Water samples have been collected almost daily for twelve years from 

 the Scripps Institution pier which extends 1000 feet from shore. Plating 

 procedures detect an average of a few hundred bacteria per ml., or about 

 the same number as is found in surface waters of the Pacific Ocean at sta- 



