What do you do?
I am interested in chemical changes in the oceans and atmosphere through time. I am particularly interested in how life influenced these changes and how the changes influenced the evolution of life. To do this, I look at the chemistry and texture of carbonate rocks that formed in ancient oceans.

Why should the general public be interested in what you do?
One of the most interesting aspects of my research to the general public is the information it reveals about the early evolution of life and how life and the chemical aspects of Earth are interrelated and dependent on each other. For example, life has shaped the atmosphere we breath by producing oxygen and removing carbon dioxide. Exploring these relationships also gives us a better understanding of how to explore for life on other planets. For example, by studing the influences of life on the early Earth, we gain a better understanding of what conditions allow life to evolve and what chemical signatures of the presence of life we could look for on other planets.

Why does it interest you?
This work is interesting to me because I want to understand where we came from and why Earth has life on it. By looking at carbonate rocks, one can read the history of Earth's ocean chemistry, and, indirectly, atmospheric chemistry and life processes. Each change in one of these processes has feedbacks that affect the others as well as future chemical conditions. Eventually, these processes produced an Earth that is habitable by humans. How that happened is an intriguing question that can be partially answered by looking at Earth's history as preserved in carbonate rocks.

What major advances/discoveries have occurred in your research field over the last 10 years?
The most important advance in Astrobiology in the past 10 years is the dramatic reconsideration of the possibility of microbial life elsewhere in our solar system. We have realized that, on Earth, microbial life can grow kilometers deep in rocks and at both high and low temperature extremes. It can persist for 10's of millions of years in salt crystals and in the guts of dead wasps encased in amber. Microbial life first appeared on Earth longer than 3.5 billion years ago, and possibly before the oldest rocks we know of formed. These discoveries, combined with new evidence for abundant water ice on Mars and liquid water below the icy surface of Europa, have revived hopes that microbial life may have been or may be present within our solar system on more than one planet. If this is true, we now have the technology to find it. The two rovers currently active on Mars, Spirit and Opportunity, are finding more evidence of liquid water in Mars' past, and future missions will focus on looking for evidence of life where there is evidence for water.