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
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Example: Photosynthetic organism (on surface) facultative chemoorganotrophs in the middle and possibly sulfate reducing microorganisms on the bottom. A mature biofilm is a 4- dimensional structure. The structure is made up of cell aggregation, interstitial pores, and conduit channels. The structures growth involves attached microorganisms, leading to the accumulation of additional cells on the surface, together with the continuous trapping and immobilization of free floating microorganisms that move over the expanding biofilm. The structure allows nutrients to reach the biomass and the channels are shaped by protozoa that graze on bacteria. Biofilms can also be formed on the inert surfaces of implanted devices such as catheters, prosthetic cardiac valves and intrauterine devices. This is because of the direct contact with human body fluids. Biofilms also can protect pathogens from disinfectants create a focus for later occurrence of disease, or release microorganisms and microbial products that may affect the immune system of a suitable host. Biofilms can become so large that they are visible. Bands of microorganisms of different colors can be visible. These thick biofilms are called microbial mats, and are found in my fresh water and marine environments. These mats are complex layers of microbial communities that can form at the surface of rocks or sediments in hyper saline and freshwater lakes, lagoons, host springs, and beach areas. They consist of filamentous