The Urban Microbiome: Uncovering the Hidden Footprint of Cities

Cities are dynamic ecosystems comprised of humans, their built environment, and a diversity of inhabitants. Among these urban dwellers are the unseen majority— the microorganisms that play an integral role in maintaining ecosystem services that are highly valued in cities. These services include air pollution abatement, water purification, nitrogen retention, biodiversity enhancement, and plant growth promotion. While much attention has been placed in studying the microbiome of indoor environments, lesser known are the ecosystem services provided by microbiomes of the outdoor built environment and green spaces that comprise urban habitats.

In this Research Topic, we provide an overview of current research on urban microbiomes of city green spaces and other elements of the built and natural environments.

There is increasing momentum in enhancing the connectivity of green spaces and human-built structures in cities, as seen in the rapid growth of green roofs, vertical gardens, and reclaimed buildings, lots, and railroads supporting agriculture and recreation. Essential to the green footprint of the city is the biological underpinning comprised of bacteria, fungi, archaea, and viruses found in soils, sediment, and plant rhizospheres and phyllospheres.

We solicit original research articles, reviews, and perspective pieces that serve to catalyze future research topics on the microbiome that could transform the design and function of cities toward greater sustainability and resilience. As 70% of the world’s population is expected to live in cities by 2050, at a population of ten billion people, it is a topmost concern to reimagine urban ecosystems to make them livable and ecologically sustainable in a changing climate and population context.