Geochemistry and Biogeochemistry
Dr. Chris Oze
Biogeochemist
My biogeochemistry research is broadly divided into two categories:
(1) To investigate the biogeochemical evolution of a variety of elements and compounds in the environment, especially with regards to how they influence or are cycled through global processes and how they may affect human health.
(2) To examine the abiotic genesis of elemental hydrogen (H2), methane (CH4), and other organic species in a variety of geologic environments (i.e. spreading centers, volcanic geothermal systems, accretionary forearcs, etc.) in order to assess key steps potentially leading to: i) the discovery of new energy resources and ii) the formation of life through laboratory studies, chemical modeling, and field data.
Environmental Biogeochemistry
I pursue projects that use trace and heavy metals to provide us with more information about large-scale global geological processes or about their potential hazard to human health. A majority of my projects focus on the chemical weathering/breakdown of mafic and ultramafic rocks (the most abundant rock types on this planet) as well as their primary and secondary minerals. For example, are toxic concentrations of chromium from ultramafic rocks and related soils a concern for human health? To what extent does vegetation suppress the uptake of certain metals available in ultramafically-derived soils into their biomass? How does asbestos, a mineral common in altered ultramafic rocks, breakdown in the human body? These studies require that I integrate biogeochemical and visualization techniques (including GIS) to understand the fate and toxicity of trace and heavy metals in the hydrosphere, geosphere, atmosphere, and biosphere.
I have also expanded my biogeochemical interests into terroir research, where I systematically and scientifically evaluate what makes one viticultural region different from another region (i.e. Burgundy versus Chateauneuf-du-Pape in France or Walla Walla Valley versus Red Mountain in Washington State). The ultimate goal of this terroir research is to create the methodology for the geospacial analysis of these very complex multi-variable systems (soil chemistry, climate, soil physics, etc.) at work in agriculture. This will allow other researchers to evaluate the viability and sustainability of agriculture/ecosystems with the advent of climate change or changes in land use.
Hydrogen Production and Methanogenesis
The primary emphasis of this research is to evaluate the inorganic formation of elemental hydrogen and organic species resulting from the interaction of geologic materials with fluids and gases over a variety of pressures and temperatures. Currently, I am assessing thermochemical reactions involving water-rock interactions that serve as H2 sources as well as the formation of organic species such as methane. My research focuses mainly on the near-surface inorganic production of H2 via serpentinization (olivine hydrolysis or the hydration of ultramafic material), which is a widespread and fundamental geochemical process resulting from the interaction of water and the olivine-rich oceanic lithosphere of this planet. In order to complete this research, I use a combination of chemical modeling and laboratory studies at the U.S. Geological Survey in Menlo Park with Robert Rosenbauer and field studies at mid-ocean spreading ridges and at field outcrops in the Circum-Pacific region. The results of this research have two significant implications with regards to energy resources and the origins of life on this planet.
As the world’s dependence on petroleum increases, the relative supply of petroleum resources are decreasing and identifying new deposits is becoming increasingly difficult. For this reason, it has become critical to examine other energy sources (especially when analogous to petroleum resources) that may become accessible with technological advances. Is the Earth capable of producing an abundant and extractable source of elemental hydrogen (H2) and natural gas not derived from the burial and transformation of organic carbon? Ultimately, this research seeks to answer this question by demonstrating how mineral-fluid-vapor chemistry by serpentinization affects the formation and stability of H2 and CH4 at elevated temperatures and pressures.
In addition to the energy-resource aspect of this research, the other major emphasis is to evaluate the inorganic formation of organic species potentially leading to the formation of life on this planet on possibly others. Here, thermodynamics and chemical kinetics allows us to examine the most favorable and geologically plausible pathways for the building blocks of life (i.e. methane, sugars, and proteins) to form. The particular environments I am investigating are mid-ocean ridge spreading centers and accretionary environments which are hypothesized to be one of the potential cradles of life on this planet. Two Bryn Mawr students working on related research can also be seen at the U.S. Geological Survey website.