Who I Am and What I Do
The earliest forms of life on Earth were microscopic. I study the evolution
of micro-organisms over the long Earth's history, and then compare our
findings with the corresponding changes in the Earth's evolution as
a planet. To gather samples, our team of scientists goes to places with
extreme environments, such as thermal springs and parts of the sea where
the salt content is high. In these extreme environments (which in some
ways mimic conditions in the primeval Earth), micro-organisms dominate,
and scientists can study how they interact with each other. Another
approach to studying micro-organisms that lived billions of years ago
involves the gathering and analyzing fossil samples.
The organic molecules, proteins, fats, sugars and nucleic acids, that
make up all living cells on our planet are made of long chains of the
element carbon. My broad research interest focuses on the biogeochemical
carbon cycle and the early evolution Earth and its biosphere. I specialize
in studying the stable isotope geochemistry of carbon in lunar samples,
meteorites, and oceanic basalts, as well as the carbon geochemistry
of ancient (Precambrian) carbonates (a carbon containing part of inorganic
molecules found, amongst other places, as a major component in the shells
My research interests extend to the new and exciting field of Astrobiology,
which seeks to identify life in other planets, and to make predictions
about what life forms future space missions may encounter. I am thus
interested in current missions to Mars, and the wealth of information
these probes are collecting regarding the extent of aqueous (caused
by water) alteration of the Martian crust, as well as the search for
fossil evidence of a Martian biosphere (that is: life on Mars).
My field work in geology and biology has taken me to Australia, Canada,
South Africa, and Mexico, in addition to many locations in the United
States. The interesting results of our research have been published
in more than 105 peer-reviewed articles and book chapters.
As a Child
Growing up, I enjoyed exploring caves. In high school, I had a great
chemistry teacher, whose enthusiasm for chemistry was infectious; I
also began learning skills that are important to a scientist: I learned
to be inquisitive and to ask questions. Later on, in college, I refined
these skills while studying chemistry, physics, and mathematics. During
this time I was introduced to the wonders of geology. I learned that
many questions that we have about our biosphere and environment require
the application of more than one of these disciplines; I also learned
the scientific method, which provides a logical approach to finding
answers to mysteries that intrigue me.
As a graduate student in the 1970s, I studied earth science (geology),
and I remember being fascinated by the lunar samples we were able to
studywhich were brought to Earth by earlier NASA lunar missions.
This experience led to my interest in space science. My thesis advisor
revealed how the power of modern anlytical chemistry can unveil the
early history of our biosphere. Later on I became involved with biology,
which added a new dimension to my research. This led to my later work
on how the carbon cycle relates to Earth's history and to astrobiology.
As an undergraduate, be sure that you get a good foundation in chemistry,
physics, and mathematics, because they are the foundation of our efforts
to learn the mysteries of life in the universe. Also, try to get some
experience in a reseach laboratory while you are in college.
I enjoy spending my time doing research, but as a senior scientist,
I need to make sure that others in my lab can have the resources and
support they need to do their own research. This takes me away from
the lab; still my leading role is a vital part of the team's research
effort. Additionally, I continue to be deeply involved in field trips
to coastal marine environments and to regions having ancient rocks,
where our teams examine the nature of microbial ecosystems and the fossil
remains of their ancestors. These trips are always educational, exciting,
and crucially important for our research. My hobbies include: photography,
hiking, and mining history. I am married and have two children, a son
and a daughter.
Last Updated: August 15, 2001