algae & bacteria 的問題

Decomposers (or saprotrophs) are organisms that consume dead organisms, and, in doing so, carry out the natural process of decomposition. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrientsfor growth and development. Decomposers use deceased organisms andnon-living organic compounds as their food source. The primarydecomposers are bacteria and fungi.

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The fungi on this tree are decomposers.
Importance of decomposers in the ecosystemWhen a plant or animal dies, it leaves behind nutrients and energy in the organic material that comprised its body. Scavengers and detritivorescan feed on the carcasses, but they will inevitably leave behind aconsiderable amount of unused energy and nutrients. Unused energy andnutrients will be present both in the unconsumed portions (bones, feathers or fur in the case of animals, wood and other indigestable litter in the case of plants) and in the feces of the scavengersand detritivores. Decomposers complete decomposition by breaking downthis remaining organic matter. Decomposers eventually convert allorganic matter into carbon dioxide (which they respire) and nutrients. This releases raw nutrients (such as nitrogen, phosphorus, and magnesium) in a a form usable to plants and algae, which incorporate the chemicals into their own cells. This process resupplies nutrients to the ecosystem, in turn allowing for greater primary production.
Although decomposers are generally located on the bottom ofecosystem diagrams such as food chains, food webs, and energy pyramids,decomposers in the biosphere are crucial to the environment. Bybreaking down dead material, they provide the nutrients that otherorganisms need to survive. As decomposers feed on dead organisms, theyleave behind nutrients. These nutrients become part of the soil.Therefore, more plants can grow and thrive.