Chapter 21 



The Distribution of Major Organic 

 Nutrients in Marine Sediments 



Gordon P. Lindblom 



jt\ part of our research program, designed to interpret the 

 contribution of heterotrophic microbes to the organic geochemis- 

 try of marine sediments consists of three major divisions. These 

 are 1) study of the distribution of organisms with deptli in 

 various types of recent sediments; 2) determination of the con- 

 centration and distribution of the major organic fractions in as- 

 sociation with the microflora; and 3) study of the complex ecology 

 of the groups of organisms found at various depths. 



The latter study requires considerable attention to so-called 

 "natural conditions" in devising laboratory experiments. Most 

 microbiologists recognize that such attention has, to date, not 

 been at all adequate in any attempt to artificially reconstruct 

 and control a given natural environment. The methods of analysis 

 of static or continuous mixed cultures, for instance, must be 

 learned before such experiments can be effectively interpreted. 



Basic to any such studies (especially those relating to nu- 

 trient limits) is the medium in which the reactions take place. 

 Therefore, the analysis of the sediment for organic nutrients as- 

 sumes particular importance. 



Reports of general biochemical analysis (other than ele- 

 mental analyses) of marine muds are few, and the samples are 

 scattered and almost always are taken from the topmost sedi- 

 ments. Most of these data have been obtained by Russian workers 

 (4, 5, 6, 7) (see Table 4). The field has been reviewed in detail 

 by Vallentyne (8). 



It seemed, therefore, expedient to determine the changes 

 in the concentrations of the major organic fractions (proteins, 

 carbohydrates, and lipids) with depth in various sediments, this 



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