Bradley B. Tolar, Ph.D.

I am an aquatic microbiologist interested in figuring out how microorganisms respond to environmental change and whether that determines “who” we find in oceans, estuaries, rivers, and lakes.

Current Research

My work focuses on seasonal dynamics of marine archaea (Thaumarchaeota) in Monterey Bay and floodplains in the western US, their role in the nitrogen cycle, and how these same organisms respond to stress in the laboratory.

Beyond the Lab

In addition to my research, I am passionate about mentoring students and participating in outreach programs to bring science to people of all ages, and am committed to making science more accessible to the public. I also work toward making STEM more just, equitable, diverse, and inclusive through mentoring and organizing programs among trainees.

Field Research

My work encompasses both laboratory and computer work, but would be incomplete without field-based environmental sampling. I have been fortunate to work in a number of different aquatic systems as a graduate student and postdoc.

Monterey Bay, California

Seasonal dynamics of marine Thaumarchaeota

Crested Butte, Colorado

Interactions between microorganisms and geochemistry in a floodplain

Sapelo Island, Georgia

Observing an annual bloom of Thaumarchaeota in a coastal estuary

Gulf of Mexico

Thaumarchaeota Populations in and around the Mississippi River Plume

Southern Ocean

Changes in archaeal populations and nitrification in spring versus summer

Gulf of Alaska

Responses of marine Thaumarchaeota to different substrates and stress

“Even if you never have the chance to see or touch the ocean, the ocean touches you with every breath you take, every drop of water you drink, every bite you consume. Everyone, everywhere is inextricably connected to and utterly dependent upon the existence of the sea.”

-Sylvia Earle, The World Is Blue

Bradley B. Tolar, Ph.D.
Research Scientist
Department of Earth System Science
Stanford University
btolar1 -at – stanford -dot- edu