Research Statement 1
Jeff R. Havig
Research Statement
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 2
Jeff R. Havig
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 21st 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 3
Jeff R. Havig
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 19th 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.