Bacteria play an important role in the environment:
Decomposition of Dead/Complex Organic Matter:
Quote:Organic carbon present in the environment in the form of dead organisms might eat up all the carbon dioxide from the atmosphere if there were no decomposers present on earth. One can imagine the situation if there were no carbon dioxide in the atmosphere. There would have been no photosynthesis in the plants and as a result no food would have been produced by plants. Decomposers or bacteria help in cycling of minerals like carbon and sulfur.
Nitrogen Fixation for availability to Plants
Through the process of nitrogen fixation, nitrogen from the atmosphere becomes available to the plants. This process takes place with the help of nitrogen fixing bacteria like Rhizobium and Cyanobacteria. These species of bacteria convert the atmospheric nitrogen into nitrates and nitrites as a part of their metabolism, and make it available to the plants. Some plants (leguminous plants) have modified themselves so well that they have a mutualistic association with the bacteria living into their tissues.
Bioremediation by bacteria
Bioremediation refers to the process of depletion/degradation of toxic compounds present in the natural environment by living organisms. Bacteria are one of the key players in Bioremediation. For example, oil spills due to oil digging operations or accidents on oil transport channels in the ocean or on the soil, is highly determinant to the healthy environment. Bacteria like Pseudomonas have been well known for the degradation of oil spills on oceans/soils.
Similarly, Contamination of heavy metals in the environment is a major global concern because of their toxicity and
threat to human life and environment. Bacteria like Alcaligenes faecalis (Arsenic), Pseudomonas fluorescens and Enterobacter clocae (Chromium) are well known for heavy metal uptake/compound metabolism.
Waste Water Treatment
Owing to their characteristics of degrading harmful chemicals and pollutants, bacteria naturally (as well as deliberately used by industries), help in treatment of waste water.