Microbiology is the study of all living organisms that are too small to be visible with the naked eye. This includes bacteria, archaea, viruses, fungi, prions, protozoa and algae, collectively known as ‘microbes’. A microbiologist is a scientist who studies microscopic organisms including bacteria, algae, and fungi. Often, they study organisms that cause disease and environmental damage or are of industrial or agricultural interest. They also study the characteristics of nonliving pathogens, such as viruses and prions.