Research Projects

Respiration in weathered bedrock and it’s contribution to critical zone structure.

In many hillslopes throughout the world, the unsaturated zone and rooting zone extend far beneath the soil in weathered and fractured rock. Yet, there are very few estimates of the amount of carbon dioxide that is respired in this environment, how it directly influences critical zone structure, and how significant it is compared to other carbon fluxes in upland ecosystems. With Jennifer Druhan, Daniella Rempe, Philip Bennett, and Jia Wang, I have investigated this at the Eel River Critical Zone Observatory.

Measurements at the ERCZO.
Measurements at the ERCZO.
A fallen tree at the ERCZO.
A fallen tree at the ERCZO.

Weathering of rock organic carbon in hillslopes.

Petrogenic organic carbon, or carbon that was lithified in sedimentary rocks, is available for oxidation and weathering in the critical zone. However, the carbon balance between petrogenic organic carbon oxidation, silicate weathering, and sulfuric acid driven carbonate weathering in ecosystems underlain by sedimentary rocks is an ongoing area of research as these rates are difficult to constrain in the subsurface. To complicate things, changing preciptation, erosion rates, subsurface water conditions, and vegetation may alter the carbon balance between different weathering processes. With Jennifer Druhan, Corey Lawrence, Daniella Rempe, and Yuchen Liu I have investigated this at the Eel River Critical Zone Observatory.

Profile of soil and saprolite at the ERCZO
Profile of soil and saprolite at the ERCZO

The importance of water stored in bedrock for biogeochemistry of the Critical Zone.

Recent studies have shown that water stored within unsaturated bedrock is an important store of moisture that sustains vegetation when soil moisture is depleted. Our research, led by Erica McCormick, shows that the use of water stored in bedrock by vegetation is prevalent throughout the continental U.S.

Trace gases as ecological currency in the critical zone.

Research Locations

Collaborator’s pages

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