Microorganisms and Ecosystems

Microorganisms are extremely important in the world’s ecosystem. Without

them, there would be a massive accumulation of waste and dead matter

everywhere. Not only this, if there were no microorganisms to break down

this waste and dead matter, than the food chain
cycle would cease to

exist, and the whole ecosystem balance would be destroyed.

The food chain in the ecosystem has the sun as its initial source of

energy. This energy is taken up by the producers, plants which make

their own food (autotrophs), and are a food source for consumers.

Organisms that eat these producers, or autotrophs are known as

herbivores since they are eating only plants. These organisms are

considered the primary consumers.

Second in line are the secondary consumers, also called carnivores

because they eat animals or meat. Next in line could be another

carnivore or an omnivore which eats plants or animals ( humans are an

example of omnivores). This chain continues with the decomposer, usually

a bacteria or fungus. These microorganisms are extremely important to

the ecosystem. They do the “dirty” work, cleaning up any dead matter and

recycling it for nutrients needed for the cycle to continue again.

Microorganisms work with plants, animals and non-living things to keep an ecosystem running. This is important because there is a delicate balance that keeps an ecosystem going. One of the many microorganisms vital to all ecosystems is the nitrogen fixing bacteria.

Nitrogen is present in large quantities in the air we breathe. It makes up around 78% of the air we breathe, compared to only around 21% oxygen. Nitrogen fixing bacteria function in the production of ammonia (NH4) and nitrate (NO3-). These bacteria take atmospheric nitrogen and convert it to these two important compounds. Generally, nitrogen fixing bacteria live freely in the soil, but some of these bacteria have a symbiotic relationship
with plants. This symbiosis is a relationship where both the bacteria and the plant benefit, the plant gets some Nitrogen for nutrition from the bacteria, and the bacteria gets sugars and other nutrients from the plants.

Legumes are plants that are very important in Nitrogen fixation. They contain symbiotic bacteria (they both benefit from the relationship) known as Rhizobia. These Rhizobia take up residence in the root systems of the plants and undergo Nitrogen fixation, producing Nitrogen which helps plants grow and thrive. In return, the microorganisms get sugar and other nutrients from the plant. These are important organisms for ecosystems because the fixing of Nitrogen affects plants, which affect, herbivores and so on down the line in the food chain. Once decomposers break down all the waste and dead matter in the cycle, the Nitrogen can be returned to the soil, fixed some again by the specific bacteria, and better, stronger plants will grow, allowing for the cycle to continue.