Microbiome

Our planet teems with microorganisms such as bacteria, archaea, viruses, fungi and algae that have evolved with their hosts over millions of years. The human body alone is estimated to contain as many microbes as human cells—about 40 trillion according to new estimates; and a few grams of soil may contain tens or even hundreds of thousands of microbial species. The complex communities these organisms form are called microbiomes. Each of them—from the human gut to the soil and from the ocean to the air—is distinct, made up of organisms that are uniquely adapted to their environment. These microbes generally perform functions that are beneficial, even essential. Of course, sometimes they are harmful. A key goal of microbiome research is to understand the interplay between helpful and harmful organisms and the factors that control this delicate balance. Indeed, researchers are just beginning to study microbiomes in as systematic way. They are trying to understand what makes a healthy microbiome, including what microbes are present and what those microbes are doing, as well as how microbiomes changes over time, how such communities stay balanced and how changes to microbiomes impact human or environmental health.