Research Statement
Jeff R. Havig
1
Dr. Jeff R. Havig
Biogeochemistry includes the intersection of Geochemistry and Microbiology, encompassing the study of geochemistry as it relates to biological system response to geologic processes and the influence of biology on geochemistry and geology. That intersection is the locus of innovation, be it the evolution and adaptation of novel biologically-catalyzed processes, or the development and utilization of novel means for quantifying the interplay of geochemistry and microbiology. How biology interacts with and influences the geochemistry of the environment in which it resides can be recorded in the rock record, leaving signatures of varying ambiguity and with differing preservation potentials (Fig. 1). Widely accepted signatures of life include fossils, biomolecules, and isotopic values.
Ambiguity increases as the probability for false positives or muddled signatures increases. Preservation potential increases as the resistivity to breakdown and destruction of the signature increases. Trace elements pose a potential new field of biological signature to explore, and were part of my focus with my dissertation research. The solubility of many trace elements in fluids (and thus availability to microorganisms) is dependent on pH, redox state, and temperature, all of which can undergo changes spatially and over time, especially in dynamic systems such as hot springs (Fig. 2). In fact, many of the most intriguing and striking signatures in the rock record are associated with geochemical change, such as the loss of mass-independent fractionation of sulfur in the rock record at 2.5 Ga, thought to represent the onset of a fully oxidized ocean. Geochemical change can happen over long periods of time and can involve large volumes of material (e.g. the oxidation of the earth’s surface). Nevertheless, these processes are most apparent where and when systems are in geochemical flux. In fact, the rock record tells us that dynamic changes can be drivers of rapid evolution.
Microbial ecosystems respond rapidly to change, providing opportunities to study the interplay of biological and geologic processes directly over time scales that are short enough for direct observation.
Tying in observations of modern systems in geochemical flux or with large geochemical gradients can elucidate their impact on signature production and preservation, providing a greater understanding of how signatures are produced, and how to interpret the signatures preserved in the rock record. My research goal is to develop and apply innovations in biogeochemistry to answering questions about how life

Research Statement
Jeff R. Havig
2 responds to geochemical change, and in turn applying what is learned to interpreting the rock record.
Importance of my research.
The forefront of science in the 21 st century is in bridging fields and making connections across disciplines. One of the greatest challenges facing science is in predicting the response of living systems to change. My background in environmental chemistry, training in geochemistry, and established professional collaborations enable me to address questions that can meld expertise and techniques that couple geochemistry with geology, biogeology, environmental chemistry, microbiology, molecular microbiology, and microbial ecology. I intend to explore the interactions and interconnections of geochemistry and microbiology through collection and analysis of samples from relevant field sites, the application of focused experiments conducted in the field, and laboratory experiments. Integrating geochemical analyses with molecular microbiology and microbial ecology through molecular work including community structure analysis and gene expression provides the framework for understanding and ultimately predicting the response of microbial communities to change.
My approach.
I approach questions through a series of steps, formulated from data and knowledge already collected by myself and others. The first step is to develop a hypothesis-driven question and then determine the best way to answer the question. Developing methods for the collection of samples from the field often lead to the design of more focused experiments to be conducted in the field or in the lab. The environment provides a natural laboratory, thus sampling over chronological, spatial, or geochemical parameter change is a powerful resource, provided variables inherent in natural and often open systems can be constrained through careful experiment and sampling design. Smaller sample sets are often more useful for answering specific questions, while larger sample sets are often required to address larger questions and gain a greater depth of knowledge of a specific field of interest. My approach is to gather a comprehensive geochemical dataset that includes contextual data, resulting in a dataset which provides the greatest opportunity for correlating results at one site to predictions for others.
An example of the success of this approach is demonstrated in a manuscript that I currently have in preparation coupling hot spring geochemical change driven by subsurface processes to microbial community change. Geochemical sampling of two hot springs over the span of 11 years captured multiple large shifts in pH, which I could attribute to changes in hydrothermal inputs through changes in anion concentrations
(specifically chloride and sulfate). This dataset enabled to determine the effects of this geochemical change on the microbial communities in these hot springs. Another example is currently out to coauthors for review where I utilize a vast geochemical framework to describe inorganic nitrogen availability in Yellowstone hot springs, and then use that to predict the occurrence of nitrogenase in hydrothermal systems.

Research Statement
Jeff R. Havig
3
Long term research goals.
I aim to explore the connections between geochemical environments and microbial communities through the coupling of geochemical and molecular sampling, focusing on environments that are dynamic, exhibiting change in physical or geochemical parameters over relatively small time scales. Examples of these systems are typically considered
‘extreme’, including hot springs, tidal zones, glacial environments, hyper-saline environments, alkaline systems, and anoxic environments. My contribution will be to incorporate broad-spectrum geochemical analyses with microbial community analyses, providing the geochemical context to aid in elucidating molecular data, and provide predictive capabilities that can be applied to similar environments as well as the past through the rock record. In meeting these goals, I plan to build a geochemical laboratory with the analytical capabilities to collect data from a wide range of samples. In this way,
I can provide graduate students with the opportunity to be involved with producing data from sample collection to sample processing, analysis, data compilation, interpretation, and through to publication.
Through my study and research, I have learned to appreciate the spirit of scientific exploration that was prevalent in the 19 th
century. As such, I would like to conduct research with the same open mind to new ideas and ways of thinking and tackling problems, while remaining rooted in a broad range of scientific expertise. I would also like to incorporate the arts into my research, especially with research expeditions, seeking to provide a better means for bringing scientific research, exploration and the spirit of first sight to the public. I feel that this goal can be met through collaborative efforts incorporating art students in research expeditions, field research, and laboratory research, with the product of the interactions and experiences yielding art that can be used by the research institution and/or collaborative governmental bodies for outreach, much in the same spirit that having artists such as painter Thomas Moran and photographer W. H.
Jackson on the 1871 Hayden Expedition to Yellowstone provided the galvanizing catalyst needed to create the first national park.