58 Marine Microbiology 



unfolded before him the results of an experiment stretching not 

 over hours or days but over millenia of time (7). The data of 

 such an "experiment" conducted in situ under natural conditions, 

 and inteipreted in the light of existing knowledge of the various 

 disciplines that must be brought to bear, can yield quantitative 

 knowledge about microbial processes in situ. Using this approach 

 for the sediments of a marine basin, it was possible to determine 

 the rate of release of nitrogenous compounds from the sediment, 

 as well as its oxygen demand (20). A similar approach should 

 yield significant data for other types of sediments or for other 

 facets of the mineralization process. 



To suggest an equally effective approach to the understand- 

 ing of mineralization processes in the water is, at the moment, 

 very difficult. Unlike the sediment, waters in the ocean do not 

 stay put. The technique of adding radioactive tracers to the 

 water and following their fate over several days, which has been 

 so fruitful in limnological investigations ( 13 and others ) appears 

 at the moment to be inapplicable to the open ocean at least. Sim- 

 ilar studies in more confined area of the sea, like bays and fjords, 

 may be worthwhile, however. The magnitude of the changes 

 taking place in the water appears from calculations to be too 

 small to detect by direct measurements over periods of time that 

 one might hope to keep track of a tagged body of water. Areas 

 may exist, where, for natural or man-made reasons, the minerali- 

 zation process is so magnified that direct measurements of rates 

 of individual processes become possible and such areas deserve 

 exploration. For most of the oceans, however, there currently 

 seems to be no alternative to the detailed and painstaking inves- 

 tigations of the oceanography and chemistry of an area. The total 

 data, brought into proper focus, may then delineate the individ- 

 ual processes taking place. In a generalized manner, this was 

 the approach of Riley (19) whose conclusions were referred to 

 earlier; this also was the approach of Gunnerson (12), in a more 

 restricted manner, in the material he presented at this symposium. 



Regardless of approacli, the goal should be the integration of 

 microbiological phenomena with the existing knowledge of physi- 

 cal, chemical and biological oceanography. 



