# Planetary microbiology: microbes, planets, and the search for life

## TL;DR

This paper explores how microbial innovations shaped Earth's history and how studying them helps in the search for extraterrestrial life.

## Contribution

The paper introduces planetary microbiology as a field connecting microbial history with planetary and astrobiological research.

## Key findings

- Microbial innovations like oxygenic photosynthesis transformed Earth's planetary systems.
- Planetary microbiology links ancient microbial biosignatures to the search for life beyond Earth.
- The field bridges molecular, ecological, and planetary scales to inform future environmental strategies.

## Abstract

Life on Earth has been shaped by transformative microbial innovations and singularities that redefined planetary systems, from oxygenic photosynthesis to biological nitrogen fixation. These unique events, occurring only once in life’s tractable history, laid the foundation for the complex ecosystems and global biogeochemical cycles around us today. The Planetary Microbiology collection in Applied and Environmental Microbiology explores how modern microbiological tools reveal the origins, early evolution, and planetary impacts of these microbial breakthroughs. Spanning deep-time studies, extreme environments, and astrobiology, contributions in this issue link biosignatures and ancient microbes to the search for extraterrestrial life. By bridging molecular, ecological, and planetary scales, planetary microbiology illuminates life’s past while critically informing strategies for the environmental and exploration challenges of our future.