Monday, July 8, 2013

Summer Blog: The Electrochemical Earth



As my colleague @lizzieday recently put it, Earth science is “redox-tastic".

Thinking of Earth as a battery is the in-thing these days. There have been so many exciting advances in looking at our Earth systems as redox systems over the last years, with several high profile papers published in the last several weeks and months, looking at oxygen fugacity in the solid earth system, with implications for the co-evolution of life and Earth, and coupled with the carbon, sulfur, iron, and oxygen cycles throughout the Earth, and throughout Earth history.

So the goal of my summer sabbatical blog is to explore the questions—is earth a battery? Which Earth systems can be examined as a battery (or fuel cell), and which cannot? What values must be quantified in order to call an Earth system a battery? Voltage drop? Current? Power? What is the connection between redox, oxygen fugacity, and electrochemistry?

My goal is not necessarily to provide specific answers, but to properly frame how I think the questions can be posed usefully, so that ideas can be quantified and tested. And to point towards the necessary quantities that must be measured in order to have answers.

My qualifications? I’ve been studying electrochemistry and surface science since my undergraduate materials science days in the mid 80s. I have been running electrochemistry experiments for over 20 years. I have a masters degree in corrosion engineering. I’ve been thinking about earth redox since I started studying geophysics in the mid 90s. I have done electrochemistry experiments at high pressure and low, in aqueous, silicate, and sulfide liquids and also solid electrolytes. I discovered isotope fractionation during electroplating in the early 2000’s. Then I predicted it theoretically, based on an extension of Marcus theory to incorporate stable isotope behavior. 

One of my research goals—long term—is to frame the need for developing a high pressure table of standard reduction potentials, to measure this table, and then show ways to use the table to understand electrochemical cycling in the Earth.

So this summer, in parallel to my working on my scientific papers and proposals, I plan to use my blog to help frame my ideas and develop my thoughts in an informal way. Comments of course are always encouraged, welcome etc.  It’s a grand experiment in coupling informal scientific writing in parallel with the formal scientific writing. I’m curious to see how it unfolds….

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