The Role of Microarthropods in Decomposition and Mineralization Processes

The vast majority of the energy and nutrients that is obtained by plants eventually becomes incorporated in dead organic matter or detritus (78, 108). Both the disappearance of this material (i.e. decomposition) and the release of the inorganic elements that are bound in detritus (i.e. mineralization) are critical to the continued productivity of terrestrial ecosystems (95). The accu­ mulation of dead organic matter not only locks away plant nutrients, but in certain ecosystems it reduces the amount of energy available for plant metabo­ lism and photosynthesis because of the insulating and shading effects of litter (41, 66). As a result, terrestrial decomposition and mineralization processes have been the subject of a considerable scientific effort by biochemists, soil scientists, bacteriologists, mycologists, invertebrate zoologists, and ecolo­ gists. A massive literature on this subject is available, and two extensive reviews have been published in the last decade (27, 93). The concept that soil fauna regulates the decomposition process has become increasingly popular (7, 22, 23, 117) in spite of the fact that the amount of soil metabolism (C02 production) that can be attributed to all soil animals is 10% or less of the total amount (12, 71, 72, 77). Fungi and bacteria are directly responsible for most of the organic matter breakdown, but a diverse assemblage of protozoans, nematodes, annelids, and arthropods greatly influence the functioning of the decomposer flora as a direct and indirect result of their feeding activities. This review examines the importance of one component of the soil fauna, the microarthropods, in decomposition and mineralization processes. A previous