People: Astrobiology Graduate Student Directory

Mark Claire
Astronomy

The Astrobiology Program has allowed me to work directly in my area of interest, which is at the intersection of various disciplines. I study the composition and evolution of planetary atmospheres, which requires that I combine knowledge from the fields of astronomy, planetary geology, atmospheric chemistry, and biology. The Astrobiology Program provides me the freedom to study in this interdisciplinary regime, something that would be difficult in a traditional graduate program.

Earth is the only planet that we know of that contains significant free oxygen in its atmosphere, and the modern day amount (~21%) of oxygen is necessary for the survival of eukaryotic life. The geologic record reveals that Earth's atmosphere has only been this oxygen rich for approximately 600 million years, and was essentially devoid of free oxygen prior to 2.3 billion years ago, with abrupt transitions in oxygen levels occurring at both these dates. Broadly, my research focuses around understanding the nature of the evolution of atmospheric oxygen, using computer modeling as my primary tool. My work includes both simple biogeochemical box models of Earth's redox fluxes, and also detailed atmospheric chemistry models of anoxic and suboxic atmospheres. With these models, I plan to investigate atmospheric structure during an "oxic transition," and hope to shed light on such diverse issues as the "Snowball Earth" hypothesis and the detectability of biosignatures in the atmospheres of extra-solar potential Earth-like planets orbiting other stars.