Awarded to: Kevin Rosso
Abstract: Understanding Torque-Generating Forces Enabling Crystal Growth by Oriented Attachment
Medal lecture in:
Session 07c in Room 2, Goldschmidt2020 - Virtual Venue on Tuesday 23rd June 05:33 - 05:36

Citation: I am delighted and honored to introduce Kevin Rosso as the 2020 recipient of the EAG Science Innovation Award. I would first like to acknowledge Mike Hochella who nominated Kevin for this award, and thank Mike for asking me to write a supporting letter and deliver this citation.
Kevin is a highly innovative experimental and theoretical geochemist and his ability to develop powerful methods in either domain has long been a great personal inspiration. It gives me great pleasure to have the opportunity to acknowledge his forefront work in computational chemistry as well as to note some of the exquisite experimental approaches he developed that have altered our understanding of the molecular structure and reactivity of the natural world.
Although Kevin has made contributions widely in mineralogy, interfacial geochemistry, and biogeochemistry, it is perhaps easiest to summarize his innovations and impacts through his work on iron redox chemistry.
Kevin perceived early on the potential for emerging computational methods to transform environmental redox chemistry. In a series of important papers beginning in 2000, Rosso and co-workers laid the foundation for predicting environmental electron-transfer rates from first principles. Electron transfer is the critical but fleeting step in every redox reaction and Kevin showed that density functional theory methods could be applied to calculate the parameters required in Marcus theory to predict electron-transfer rates. Following initial successes for homogenous outer-sphere electron transfer in simple solutions, Kevin has demonstrated the power of this approach in diverse geochemical and biochemical systems. We now know why aqueous geochemical conditions control the oxidation of ferrous iron in water, and how crystal structure controls the rate of electron transfer in iron oxides, clays and other minerals. Moreover, Kevin’s computational work vividly reveals the energetics and pathways for electron flow through microbial cytochromes—specifically through the iron sites in heme cofactors.
Kevin also understands the central role for observation, and has the imagination and technical skill to design insightful—and sometimes audacious—experiments to test concepts and hypotheses. In a deceptively simply but profoundly important contribution, Yanina and Rosso showed that solid-state electron transfer can link redox reactions occurring on different hematite faces, substantially enlarging our appreciation of the pathways for electron flow in soils and other settings. By painstakingly polishing the tips used in atomic-force microscopy, Kevin and his group were able to quantify the directional forces between mineral surfaces generated by van der Waals forces and by water hydrogen bond interactions. These forces control the stacking or hydrated clay minerals and the oriented attachment of mineral particles.
To summarize Kevin’s career to date, experimental and computational methods have gradually been catching up with the incisive molecular-scale ways that Kevin understands and thinks about mineral, geochemical and biochemical systems, and Kevin has always been at the forefront in applying them to challenging and important questions.
As well as possessing a clear vision for his own research priorities, Kevin is a generous mentor, an effective team leader and a superbly constructive collaborator. In my career, when I knew that molecular simulation was needed to understand the molecular basis for redox reactions, the approach was clear – turn to Kevin, who is always fascinated by new problems and somehow finds the time to develop bespoke calculational methodologies. And now, a cadre of younger researchers trained by Kevin use his methods in my lab and research groups around the world.

I will close on a short statement from Mike Hochella:
“Kevin, you are an exceptionally gifted scholar at an international level.  This is not the first, nor will it be the last great honor that has or will pass your way.  I could not be more proud of you and your achievements.  My life in science has been remarkably brightened by you.  Thanks for everything my dear friend.”
Mike and I are thrilled that Kevin is the recipient of the 2020 Science Innovation Award and we look forward to many more innovations and discoveries to come.

Benjamin Gilbert
Lawrence Berkeley National Laboratory, USA
Mike Hochella
Pacific Northwest National Laboratory, USA

Response: I am truly humbled and grateful to accept the honor of the 2020 Science Innovation Award of the EAG. It is particularly enriching given its distinguished Werner Stumm Medal namesake, an awe-inspiring giant in aquatic chemistry that I have long admired. This award, I will perennially cherish with amazement.
From my present vantage of 22 years as a professional, what comes to mind is the abundance of influential mentors, colleagues, friends and family that have helped shape my scientific interests and career goals. It is with trepidation that here I attempt with all earnestness to reduce it to its essence, though a woefully inadequate acknowledgement of the breadth of interactions that I have so genuinely enjoyed and benefited from over the years. To put the task into perspective, for example, it was somewhat stunning to discover that my various co-authors now number greater than 500. (Where to begin?)
One of the most prominent attributions I can make for any present success, upon which I increasingly reflect, are the Professors of Geological Sciences at my undergraduate institution, California State Polytechnic University at Pomona (Cal Poly Pomona). Here, near my teenage home at this unglamorous commuter-based institution, one that is dwarfed by a host of prestigious surrounding universities, would I find my calling and passion for science. I entered with an ill-fated vision in the field of architecture; I graduated with bulging sails ahead in Geochemistry. This small underfunded department of about six professors, excited about and dedicated to their small cadre of students, is where my compass needle found strong field lines. Crucial to this, the late David Jessey, my undergraduate thesis advisor, deftly unveiled the field of Geochemistry for me, and rendered clear its evergreen importance to society. On account of him, I often wonder how many other foot-soldiers of science education go unsung while indelibly changing the world.
This catapulted me as a student into the grander halls of forefront geochemistry research in the Department of Geosciences at Virginia Tech. Though I benefited instantly from its diversity of excellent faculty, students, and research, a few key individuals meticulously nurtured into me a solid foundation in geochemical principles. This includes Bob Bodnar, my M.S. advisor who instilled in me the importance of equilibrium thermodynamics as well as equipping me with insightful skills in scientific writing. My horizons grew substantially further under the care of Jerry Gibbs from whom I learned the eloquence of mathematical crystallography and computational mineralogy, the late Don Rimstidt for experimental solid-water interfacial geochemistry, and fellow graduate student Udo Becker for quantum chemistry and molecular simulations. In all such things, however, I obtained a grander view and appreciation of geochemistry and the natural environment from my Ph.D. advisor Mike Hochella, who single handedly walked me into the very large room called nanogeoscience, and set me loose at the nexus of mineral-water reactivity and ultra-high vacuum surface science. This kind of hybrid disciplinary approach was, at the time, just beginning to blossom into the field of molecular interfacial geochemistry.
That educational journey transported me into an early career research scientist position at PNNL in 1998 where my ambitions flourished, immersed with world-class expertise and capabilities in experimental, theoretical, and computational interfacial science. It was a great joy to be taken under the wing of internationally recognized thought leaders like John Zachara, Andy Felmy, Jim Rustad, Michel Dupuis, and Jim Fredrickson, and there be given golden opportunities to pursue a variety of science questions that mostly centered around my personal interests in the kinetics of redox reactions in natural systems. It was there, under stable funding support, encouragement and a multidisciplinary collaborative culture that I was able to deep dive into the chemical physics governing electron transfer reactions, and marry this knowledge with molecular simulations to begin to predict rates of processes that geochemists, environmental scientists, biogeochemists, and material scientists care about. It has also been at PNNL, in its rich and immersive scientific environment, that enabled a host of new science frontiers for me to learn and explore, bolstered and sharpened by the many talented scientists, post-doc’s, and students that have comprised our Geochemistry Group for these two decades.
Finally, I gratefully acknowledge the love of my life, my wife Carolyn Pearce, for her transformational and unabating support, and for the joy that she and my children Ethan and Natalie Rosso continually bring me. I would be not anywhere close to this far without them, and in their presence feel convinced of a bright future ahead.

Kevin Rosso
Pacific Northwest National Laboratory, USA
2020 EAG Science Innovation Awardee