ABSTRACT
The first law of thermodynamics indicates that matter can neither be created nor destroyed. Within ecosystems, this law governs the transformations of energy and nutrients between compartments. Energy and nutrients are contained within the living biomass of the plants and animals forming communities within the ecosystem as energy and nutrient stores. The transformations of energy and nutrients that occur among these is a result of trophic interactions within food chains and webs and are regarded as the processes that occur in ecosystems. The nature of these stores of nutrients and energy within individual organisms and communities and the movement of material among them is the science of ecology. We will consider here the role that fungi play in some of the major ecosystem processes, namely the process of transforming carbon dioxide and nutrients into plant biomass by photosynthesis, the energy and nutrient transformations among components of food webs, and the transformations carried out by saprotrophic decomposers that use the energy and nutrients from dead plants and animals, resulting in the mineralization of nutrients for new plant growth. This latter process is referred to as energy and nutrient cycling. In addition, we will explore the interactions of human influence on the processes carried out by fungi in the ecosystem.
