therefore, to find more organic detritus in an aquatic system than living 

 biomass. The decomposition of organic detritus can be considered as 

 an interaction between detrital particles and bacteria. The rate of 

 change is given as a bimolecular second order reaction. A mathematical 

 formula is given for this process, although it is stressed that the 

 function is not relatively simple. It is further expressed that 

 additional information and study in the areas of grazing, sedimentation, 

 and/or physical transport would be beneficial in determining rate of 

 change in detritus concentration. Study is needed in various areas 

 in order to provide a general idea of the importance of detritus in 

 any aquatic system. (H.D.) 



Keywords: detritus, nutrients, aquatic ecosystems 



III-A-4 



Dickinson, C.H., and G.J. Pugh, eds. 1974. Biology of plant litter 

 decomposition. Academic Press, New York, 2 vols. 



In the past much emphasis has been placed on finding out what organisms 

 occur in particular processes such as litter decomposition and in habitats 

 such as soil. Within some disciplines the emphasis is moving toward 

 autecological studies. Recent volumes have tended to be concerned with 

 particular groups of organisms in specific habitats, such as fungi in 

 soil, animals in soil and marine bacteria. We now see the need to 

 synthesize the knowledge that has been obtained during studies of specific 

 groups of organisms and to draw attention to their interrelationships 

 in plant litter decomposition. 



A central process in the life cycle of all green plants is the 

 decomposition of their remains. During this decomposition many comple- 

 mentary and/or competing organisms are active. Frequently the processes 

 of decomposition begin before the plant part senesces and the sequence 

 of organisms involved is related to the type of plant material and the 

 environment. Decomposition is then conditioned by the nature of the 

 plant tissues, the range of organisms able to decompose these tissues, 

 and the environment. 



The arrangement of the chapters in this book follows the above pattern, 

 and the quantity of material involved has made it necessary to divide 

 the book into two volumes. In Part I, which constitutes Volume 1, 

 the primary emphasis is placed on the type of litter. In this context, 

 litter is taken to include all plant remains, which range from still 

 standing dead trees to the decomposing hyphae of fungi and cells of 

 bacteria. The organisms involved in decomposition processes are discussed 

 in Part II, which forms the first part of Volume 2. 



The second part of Volume 2, Part III, is concerned with the environ- 

 mental conditions under which breakdown occurs over the whole global 

 surface. Terrestrial , freshwater and marine environments are considered 



91 



