Geobiology integrates many disciplines, from genomics to paleoenvironmental modeling to paleontology and geochemical analysis. They can be fruitful individually but, when combined, result in profound insights about life—past, present, future and elsewhere.

Nevertheless, if you were to ask 50 people, including 50 research scientists ‘what is geobiology?’, you would most likely get at least 30 different answers. Actually, it is not difficult to give a broad definition.


Geobiology includes the integration of (clockwise, from top left) genomics, environmental microbiology, paleoenvironmental models, theory, geochemical analysis, and environmental patterns

Geobiology is the study of the interactions that occur between the biosphere (living organisms and their products) and the geosphere. Therefore, it must include elements of the atmosphere, the hydrosphere (marine and freshwater), and the lithosphere.
Because such interactions in our natural world are numerous and complex, there are dozens, if not hundreds of ways to approach the study of geobiology—from molecular genetics, to field geology, to geochemistry, to physics and computer modeling. Thus, in gory detail, the definition of the field of geobiology is murky at best.


Shamelessly gratuitous really cool mars photo, courtesy of NASA Spirit rover, February 10th, 2004. We hope our search for early life on Earth will assist the search for life elsewhere in the solar system. What would a geobiology website be without a Mars photo?

In our group, we approach the study of geobiology through the use of ancient molecular fossils, called biomarkers. The following tree provides a summary of the end goal of the study in our laboratory. We would like to fill out each of these branches—that is, connect a particular molecular fossil with each specific group represented in the tree of life. By doing so, we have a way to look into the past and see how the diversity and distribution of organisms has changed through time, and how those changes are related to changes in the earth system as a whole.


Figure courtesy of J.J. Brocks

For those who haven’t kept up with biology since 9th grade, this is the new organization of living organisms. Yup, that’s right. They’ve gotten rid of the 5 kingdoms. In the late 1970s, Dr. Carl Woese and his colleagues at the University of Illinois discovered an entirely new group of organisms—the Archaea. They were studying relationships among the prokaryotes using DNA sequences, and found that there were two distinctly different groups. Those ‘bacteria’ that lived at high temperatures or produced methane clustered together as a group well away from the usual bacteria and the eukaryotes. Because of this vast difference in genetic makeup, Woese proposed that life be divided into three domains: Eukaryota, Eubacteria, and Archaebacteria. He later decided that the term Archaebacteria was a misnomer, and shortened it to Archaea.