Biogeochemical Cycling and Introductory Microbial Ecology

The physical environment: Microorganisms are influenced by biogeochemical cycling, and also by their immediate physical environment. This includes soil, water, deep marine environment, plant, or animal host.
The Microenvironment and niche: A microenvironment is the specific physical location of a microorganism. It is a very small, specific area, distinguished from its immediate surroundings. These factors include the amount out light exposure, the degree of moisture, and the range of temperatures. An example: The side of a tree that is shaded from sunlight is a microenvironment that typically supports a somewhat different community of organisms than is found on the side that receives regular light. Niche: A niche is a way of life of a species. Each species has a separate, unique niche. In the microenvironment, the flux of required electron donors and acceptors, and nutrients to the actual location of the microorganism can be limited, but at the same time, waste products may not be able to diffuse away from the microorganism at rates sufficient to avoid growth inhibition by high waste product concentration. These fluxes and gradients create a unique niche. A unique niche includes the microorganism, its physical habitat, the time of resource use, and the resources available for microbial growth and function. Microorganisms can create their own microenvironments and niches. Example: Microorganisms in the interior of a colony have markedly diff microorganisms and niches than those of the same microbial population located on the surface edge of the colony.
Biofilms and microbial mats: A biofilm is an organized microbial system consisting of layers of microbial cells associated with surfaces. Simple biofilms develop when microorganisms attach and form a mono layer of cells. This depends on the