Chapter XVIII — 201 — Microbiology of Inland Waters 



him, H2S reacts with iron intracellularly to give black inclusion bodies 

 0.5 /x in diameter or larger: 



HjS + Fe(HC03)j = FeS + 2 HjCO, 



After the death of the bacteria, crystals of ferrous sulfide are liberated. 

 The Black Sea gets its name from the color caused by ferrous sulfide. 



IssATCHENKO and Egorova (1939) were unable to confirm Egounov's 

 celebrated hypothesis that there is a "bacterial plate" (see p. 161) or zone 

 of sulfur bacteria in the Black Sea where oxygenated surface water merges 

 with H2S-containing bottom water. After failing to find sulfur bacteria in 

 samples taken at one meter intervals throughout the boundary layers, it 

 was concluded that H2S must be oxidized abiogenically as it diffuses up- 

 ward into oxygenated water. However, Ravich-Sherbo (1930) found 

 large numbers of Thiohacillus thioparus in the so-called "thin layer" or 

 "bacterial plate." Knipowitsch (1926) reported the presence of Thio- 

 pedia rosea and other sulfur bacteria in the Black Sea as well as in the 

 Caspian Sea and the Sea of Azov. 



In the Caspian Sea, where hydrographic and microbiological condi- 

 tions are akin to those in the Black Sea, Butkevich (1938) found large 

 numbers of sulfate reducers. Near the mouth of the Volga River he found 

 from one to two million bacteria per ml. of water, or the equivalent of a 

 bacterial biomass of about i gram per cubic meter. This compared favor- 

 ably with the biomass of plankton algae. The bacteria were very active 

 biochemically. Denitrifiers were widely distributed. Both denitrifying 

 and nitrifying bacteria were reported in the Black Sea by Knipowitsch 

 (1926). As pointed out by Issatchenko (1926), the presence of H2S pre- 

 cludes the possibility of nitrification in deeper water, but nitrifying organ- 

 isms were abundant in shallow, sandy, or shelly bottoms. 



The investigations of Poteriayev (1936) on sanitary problems attend- 

 ing the disposal of sewage in the Black Sea are noteworthy. Except in 

 closed basins such as bays or firths, there is generally an intermixing of 

 sea water with sewage, which results in a rapid coagulation and biochem- 

 ical oxidation of the latter. 



Ravich-Sherbo (1936) diagnosed a fatal disease of Amphioxus lan- 

 ceolatum in the Black Sea as being caused by a red chromogenic bacterium 

 which he described briefly, but did not identify. 



Bacteriology of Russian limans : — The shallow salt lakes bordering 

 the Black Sea have been the subject of extensive and intensive study by 

 microbiologists. Unique conditions exist here where the salinity ranges 

 from a few parts per thousand (when flooding rivers overflow into the 

 mud lakes or limans) to concentrated salt solutions following prolonged 

 periods of drought and evaporation. Especially noteworthy are the 

 voluminous contributions of Rubentschik and associates on the limans 

 or mud lakes around Odessa. 



Representative of the work of Rubentschik (1925) are his observa- 

 tions on urea-splitting and proteolytic bacteria which are active in saline 

 media at 0° to — 2° C. He isolated and described Sarcina psychrocarteria 

 and Bacillus psychrocartericus, both of which attacked urea at — 2.5° C. 



From the Kilyalnizki Liman, Rubentschik (1928a) isolated sulfate 

 reducers which used the decomposition products of cellulose as an energy 

 source but not cellulose itself. The sulfate reducers were able to grow in 

 media containing from o to 20 per cent NaCl. In nature, the bacterial 



