Pseudomonas and Thiobacillus carry out the following:
Both Pseudomonas and Thiobacillus are important bacteria involved in the nitrogen cycle, which is a crucial biogeochemical cycle responsible for converting nitrogen into various chemical forms that are usable by living organisms.
Pseudomonas species are known for their ability to perform denitrification, a process in which nitrate ions (NO₃⁻) are reduced to produce nitrogen gas (N₂) or nitrous oxide (N₂O), thereby returning nitrogen to the atmosphere. This process typically occurs under anaerobic or low-oxygen conditions, and it helps regulate nitrogen levels in the soil and water, preventing the accumulation of excess nitrates that can lead to environmental problems such as eutrophication.
Similarly, Thiobacillus species, which are chemoautotrophic bacteria, also participate in nitrogen transformations including denitrification. Besides their well-known role in oxidizing sulfur compounds, some species of Thiobacillus contribute to denitrification, thus playing a dual role in both sulfur and nitrogen cycles.
Denitrification is an essential process because it closes the nitrogen cycle by releasing nitrogen gas back into the atmosphere, making nitrogen unavailable to plants until it is fixed again by nitrogen-fixing bacteria. This balance is vital for maintaining ecosystem health and fertility.
Hence, the correct process carried out by both Pseudomonas and Thiobacillus is denitrification.
Correct Answer: Denitrification