Microaerophiles are microorganisms that require low levels of oxygen for growth, typically between 1% and 10%. Unlike aerobic organisms, which thrive in normal atmospheric oxygen levels, microaerophiles cannot survive in environments with high oxygen concentrations. They often inhabit specific ecological niches, such as the human gut or certain soil types, where oxygen levels are limited. These organisms play important roles in various biological processes, including fermentation and nitrogen fixation. Examples of microaerophiles include certain species of Helicobacter, which can cause stomach ulcers, and Campylobacter, a common foodborne pathogen. Understanding microaerophiles is crucial for both medical and environmental microbiology.