Question

………... play an important role in the cycling of sulfur, nitrogen, and carbon in an ecosystem, irrespective of ecosystem, aquatic or terrestrial.

Answer 1

Hint: Bacteria is a prokaryotic microorganism that consists of numerous shapes from spherical to spiral and appeared first on earth which inhabit soil, water, radioactive waste, acidic hot springs, and the deep biosphere.

Complete answer:
In an ecosystem, bacteria are considered as micro consumers. They play an important role in the cycling of sulfur, nitrogen, and carbon which is completed due to the work done by the bacteria irrespective of the ecosystem aquatic and terrestrial. The microscopic bacteria help in decomposing and breaking down dead organisms in the ecosystem and release the nutrients back into the environment. Bacteria are known as producers in many ecosystems and make food for the entire ecosystem where the bacteria do photosynthesis using carbon dioxide and sunlight and chemosynthesis by using chemicals to make food. Humate is a nutrient-rich compound that is used by farmers as a fertilizer and is broken down by the Bacteria known as actinobacteria to other compounds that are needed for plant growth. Bacteria protect themselves from viruses by fragmenting viral DNA with an endonuclease. The endonuclease is also known as restriction enzyme which is a protein that is produced by bacterial cells which leaves DNA at specific sites along with the molecule.

Additional information:
Bacterias have caused more human that's on earth than any other known cause directly through the diseases of dysentery, Cholera, pneumonia, and others throughout the history but at the same time provided many essential services to earth which includes the plant productivity to be sustainable and the humans to live basically without microbes which cannot be possible for humans to be alive. They are powerful collectively and produce oxygen to $50\%$ of total oxygen on the earth and $75\%$ of nitrogen to the atmosphere by removing $92\%$ from the atmosphere by bacteria. They were responsible for the methane production which is put into the atmosphere and functions differently to gain energy and give the impact of microbes on the ecosystem and globe.

So, the correct answer is 'Microconsumers (Bacteria)'.

Note:
The bacteria help in the production of ethanol and certain enzymes and make biogas such as methane. It helps in cleaning up oil spills and toxic wastes. It kills the plant pest and ferments food.