Chapter V 



67 — 



Distribution in the Sea 



downwards to depths of 40 to 50 meters and then decreased with depth 

 until the bottom was reached. Otto and Neumann (1904) found some- 

 what more bacteria in the Atlantic Ocean between Europe and Brazil at 

 depths of 50 to 100 meters than in surface waters and virtually no bacteria 

 at depths exceeding 200 meters. Drew (191 2) reported the number of 



BACTERIA/ML. X 100 

 1 2 3 4 5 



ioo/(: 



20°C. 



SEA BOTTOM 



Fig. 7. — Vertical distribution of phytoplankton, bacteria, sunlight, and tem- 

 perature in the Pacific Ocean, based upon the average results at several diiTerent 

 stations off the coast of Southern California. The bacterial population is given in 

 terms of numbers per ml. as indicated by plate counts, and the phytoplankton pop- 

 ulation is given as the numbers of diatoms per liter of water (ZoBell, 1942a). 



bacteria found at different depths of sea water off Andros Island, West 

 Indies, as follows: 



o to 50 fathoms 

 200 fathoms 

 4CX) fathoms 

 600 fathoms 

 800 fathoms 

 Bottom deposits 



Too numerous to count 

 160 bacteria per ml. 



16 bacteria per ml. 



17 bacteria per ml. 



o to 2 bacteria per ml. 

 160,000,000 bacteria per ml. 



Table XVIII summarizes the average number of bacteria found at 

 different depths by Lloyd (1930) at certain representative stations in the 

 Clyde Sea. The water samples from the "bottom" in Table XVIII were 

 probably taken a meter or two off the bottom, because Lloyd (1931a) 

 reported the presence of many thousand bacteria per ml. of bottom depos- 



