Chapter 18 



Behaviour of a Suspension of Microbes, 



Migrating- Through Sediments Under 



Marine and Limnie Conditions 



M. Wagner and W. Schwartz 



I 



t is of interest to learn how microbial cells will behave in 

 groundwater moving in sediments and sedimentary rocks, or in 

 surface water moving in a vertical direction from the surface of 

 the earth into the underground. Different events may happen: 

 Active or passive migration of the cells with/without multiplica- 

 tion may occur within the streaming water and the substream 

 sediment; cells may grow through the sedimentary material, form 

 surface films, ("Aufwuchs") attach to the surface of particles 

 of the sediment, or be retained, adsorbed, or eluted within the 

 sediment. 



The microbes used in our experiments were: 

 Micrococcus sp., strain B/lc (0.6 x 1.0 /j.),^ isolated from drilling- 

 mud of an oil-well. 

 Nocardia sp., strain beach sand I ( 1.0 x 2.4 /<, threads up to 12.0 /», 



coccoidal cells 0.8 /' diameter), isolated from beach sand. 

 Serratia marcescens, (1.0 x 1.5-2.2, average 1.8 p.), culture col- 

 lection. 

 Strain H/8b, (1.0 x 1.5-2, 2 /x), rods forming threads, no flagella 



and spores, isolated in 1949 from oil of an oil-well. 

 Bacillus mycoides, (1.5 x 4-5, average 4.6 p.) culture collection. 

 We have tested the vertical migration of the cells in model 

 experiments with suspensions of bacteria in seawater (3.5%) 

 and in fresh water through an 80 cm-column (Fig. 1) of two 

 types of sandy sediments (Table 1). 



^ (In brackets, size of the cells from broth agar cultures, 3 days old.) 



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