ZoBell — 6 — Marine Microbiology 



seals. Careful studies by more modern workers have established that the 

 excrement of animals like those examined by Levin usually contains an 

 abundance of microorganisms. 



Observations on the Ruckreise, while crossing the Atlantic Ocean from 

 Gibraltar to New York, were made by Minervini (1900). He found a 

 constant small population in surface waters with little difference between 

 coastal water and that from the high sea. In the North Atlantic Ocean he 

 found 8 to 140 bacteria per ml. in water from a depth of 5 to 10 meters. 

 Vibrio species predominated. In appraising his results it should be noted 

 that he collected samples through a sea cock in the engine room while the 

 vessel was traveling and he often stored his samples on ice for a few hours 

 before examining them. The significance of sampling technique and of 

 storing samples is discussed in Chapter III. 



In Drobak Sound, an arm of Oslo Fjord, Schmidt-Nielsen (1901) 

 found from 40 to 420 bacteria per ml. at a depth of 25 meters and an aver- 

 age of only 26 per ml. at the surface. However, this vertical distribution 

 of bacteria even in sheltered areas was obliterated during periods of rough 

 weather. He pointed out that the term "surface water" is relative, sug- 

 gesting that during periods of extreme calm it may make a difference 

 whether one examines the topmost layer of water or layers only a few mm. 

 below the surface. Many of the bacteria were chromogenic. 



Gazert (1906a) had charge of the bacteriological investigations of the 

 German South Polar Expedition on the ship Gauss. He was only moder- 

 ately successful in demonstrating bacteria by the methods used by 

 Fischer. On a trip from Kiel to Capetown, Gazert (19066) found an 

 average of fewer than one bacterium per ml. of surface water from the 

 open Atlantic Ocean. Growth occurred in all loo-ml. tubes of meat in- 

 fusion broth inoculated with 20 ml. of sea water. On one occasion he re- 

 covered 6 bacteria per ml. by plating water collected from a depth of 1800 

 meters where the temperature was 2.5° C. Surface water samples col- 

 lected while cruising from Kerguelen Island in the Indian Ocean into 

 South Polar waters and back to Capetown contained relatively few bac- 

 teria except where there was much seaweed. In water around seaweeds 

 only 10 to 30 bacteria per ml. were found. 



In the deepest water from South Polar seas Gazert (1906&) found rel- 

 atively few bacteria, but appreciable numbers of bacteria were found in 

 the bottom ooze or sediment even from depths as great as 5320 meters 

 where the temperature ranged from — 0.2° to — 2.0° C. He found bacteria 

 in the intestinal contents of seals, fishes, and albatrosses but not in pen- 

 guins. Most of the bacteria isolated by Gazert grew at 0° C. but the 

 optimum temperature was around 20° C, 



Gazert attributed the paucity of bacteria in the open ocean to the 

 low content of organic matter. Like his predecessors, he found many 

 more bacteria near shore, and especially in harbors, than in the open sea. 

 It must be emphasized, however, that the actual numbers of bacteria 

 reported by various workers are by no means comparable because different 

 procedures were employed in the analysis of the samples. It may be sig- 

 nificant that Gazert used a metal cylinder for the collection of water sam- 

 ples (see page 33). 



Gazert (19066) gives an excellent description of the ship's laboratory. 

 He stressed the difficulties with which the bacteriologist has to contend 

 while examining water or mud on a small rolling ship. 



As a member of the Swedish South Polar Expedition, Ekelof (1907) 



