Is soil microbial community thermodynamic efficiency and carbon use efficiency dependent on biodiversity?

As ecosystems develop on newly exposed land surfaces, such as result from volcanic eruption, landslides and industrial activities (open-cast mining), they tend to mature along what is commonly known as a "successional" gradient - e.g. lichens are replaced by grasses, which in turn are replaced by shrubs, then finally tree-dominated systems. Theoretical frameworks have suggested that the longer these systems have developed, and the more complex they become in terms of their food webs, then the more efficient they become in utilising resources. In particular mature ecosystems tend to retain nutrients - younger systems tend to be "leaky", with nutrients being lost into surface and groundwaters, because of the disconnected nature of the food webs within them. Measurements aimed at determining whether this relationship really holds true are difficult to make in mature systems because of their complexity and issues of scale - it is difficult to measure everything going in (in terms of energy and materials) and everything coming out. One area in which some indications of the increased efficiency of forest systems over developing systems is that they tend to produce less waste heat. We hope to take these two ideas - scale problems and waste heat production, and investigate them in systems which are small scale, but of varying complexity and biodiversity - i.e. soil systems of differing maturity, and we have some initial data that supports this view. We shall measure these changes using a very sensitive system called a microcalorimeter, which can detect small amounts of heat output from soil when it consumes resources, such as glucose. If our theory is correct then the amount of waste heat produced per amount of glucose added to soil will decrease as we move from newly developing ecosystem soils to developed ecosystem soils.