Index >> Fundamentals of Microbial Ecology >> Bio-Geochemical Cycle(BGC)

BGC cycles include physical transformation (precipitation, fixation, etc.), chemical transformation (biosynthesis, biodegradation, etc.) and various combinations of physical and chemical changes.

All living organisms participate in the bio-geo chemical cycling but microbes play a major role in the process. In the BGC cycling, energy is absorbed, converted, temporarily stored and eventually dissipated (energy flows through the ecosystem). This flow of energy is fundamental to the functioning of ecosystem.
When energies flow through the ecosystem, materials undergo cyclic conversions that tend to retain materials within the ecosystem. The cyclic nature of material conversions leads to dynamic equilibrium between various forms of cycled materials.

The BGC cycles usually include negative feedback control mechanisms so that any abnormally high pool level corrects itself and the system returns to the equilibrium state.

Reservoirs The various chemical forms of a particular element constitute so called pools or reservoirs and the reservoir sizes can vary greatly from habitat to habitat. Reservoir size is an extremely important parameter to be considered in connection with possible distribution of a cycling system.

In BGC cycling, small, actively cycled reservoirs are the most prone to disturbances by either natural or human causes.