Did you know that the second largest source of biomass on the planet after plants is microorganisms? Too small to be seen with the naked eye, microorganisms and their unique capabilities make them a critical component of how ecosystems function. DNA sequencing, the technology that allowed us to sequence the human genome, can be applied to environmental microorganisms to reveal the diversity of different types and their unique capabilities, compared to other organisms, that have otherwise been difficult to observe and study. In this session, we will explore what makes microorganisms so special, how we apply DNA sequencing technology to study these organisms, and how understanding microbial diversity and function through DNA sequencing could be used to predict the ecosystem response to climate change and remediation efforts, such as in the Chesapeake Bay.