510 CYCLES OF ORGANIC AND INORGANIC SUBSTANCES 



quantity of organic matter in living form in sliallow waters, and 

 exceeding it very much more overall throughout the deeper parts 

 of the ocean; their ecological significance is likely to be no less. 

 Indeed, both Collier (1958) and Provasoli (1958) have drawn 

 attention to the role the massive amounts of some organics may 

 play in maintaining those ectocrine-producing bacteria which are 

 so essential to the life of other microorganisms — once again "group 

 symbioses on the large scale." We know also that some at least 

 of the smaller molecules (amino acids, etc.) can be used directly 

 as nutrients by many plankton algae,* thereby short-cutting the 

 ecological cycle, and a reference here may not be inappropriate 

 to the microorganisms of the layers beneath the photosynthetic 

 zone itself. In recent years we have had several hints that signifi- 

 cant elements of production may proceed in deeper layers [or 

 under ice (Rodhe, 1955)], perhaps ultimately dependent on the 

 activities proceeding above, but directly the result of micro- 

 organic activity in the absence of light, in the muds and in the 

 deeper layers of the ocean. The late Dr. Fabius Gross gave me 

 the first hint of this, and Ferguson Wood (1958) has recently 

 given another, with his evidence of heterotrophic diatoms in the 

 deep community (further hints are given by Lewin and Lewin, 

 1959). Quite apart from their functions in the depths, sooner or 

 later the products of such activity come to the surface in upwell- 

 ings, etc. ; useful work might well include careful investigation of the 

 physiological qualities of waters from some of the classical areas of 

 upwelling. 



9. Meanwhile, despite Krogh's (1931) masterly disposal of 

 Putter's (1908) rash claims, the possibility that some dissolved 

 organic matter in relatively gross amounts may yet be shown to 

 provide nutriment for aquatic animals cannot now so easily be 

 dismissed (Morris, 1955). At its grosser level, this possibility is 

 more analogous to the relationships between parasite and host 

 rather than to the coordinated hormonal interrelationships of the 

 body cells. Parasites, harmful and tolerated, live among and on 



* A fascinating new aspect of this is sliown by Smith el al. (1959) in their work on 

 the possible preference by some algae for complexed carbon dioxide as a carbon 

 source and the role this may play in photosynthesis, etc. 



