Daniel O Breecker

Areas of Expertise

The Breecker Group studies biogeochemical processes occurring at or near the land surface. We study soils and paleosols, caves and stalagmites, and other materials, such as volcanic glass, that give us insight into ancient Earth. We study timescales ranging from seasonal cycles to hundreds of millions of years. We use observations, mathematical models and both laboratory and field-based experiments to address an evolving range of questions. To learn more about the research we are doing, please see our research group website.

Postdocs

Jiawei Da
Hello, my name is Jiawei Da, and I am a geochemist and paleoclimatologist. I am interested in understanding the behaviors of Earth's climate system, especially the terrestrial ecosystem, during past hothouse climates. To quantitatively interpret information from geologic archives, I leverage novel geochemical techniques (e.g., clumped isotope thermometry, triple oxygen isotope) and proxy system models to seek better constraints on...

Elizabeth Cassel, now at the University of Idaho
Liz is advancing the understanding of the paleoelevation of the western United States and the Western Cordillera in South America. She is a leader in the use of felsic volcanic glasses to determine the past elevation of Earth's land surface.

Timothy Gallagher, now at Kent State University

Graduate Students

Alexander Janelle , Ph.D., expected 2027 (Co-supervisor)
I am broadly interested in the intersection between karst, water resources, and natural and anthropogenic climate change. Texas' climate is at the convergence between the wet southeast and arid southwest. While this transition historically occurred at the 100th Meridian, it has been moving eastward bringing drier conditions to central Texas. My dissertation research compares proxy data produced from speleothems (cave...

Neelarun Mukherjee , Ph.D., expected 2026 (Committee Member)
My research focuses on unraveling the complexities of subsurface flow and reactive transport. I am currently developing robust models to explain these processes, with a current emphasis on transport dynamics in thawing Arctic permafrost driven by global warming. Beyond water cycle implications, my work explores the release and fluxes of greenhouse gases (CH4, CO2, NOx) stored in permafrost. To understand...

August Aalto (Co-supervisor)
I'm a third-year PhD candidate in the Department of Earth and Planetary Sciences co-supervised by Profs. Daniel Breecker and Paola Passalacqua. I'm interested in soil science, geomorphology, remote sensing, and environmental history and impact. For my PhD research, I'm pursuing a process-based understanding of soil development in deltaic wetlands for new insight into the dynamic role of organic matter in...

Nicole Ferrie (Co-supervisor)
Nicole Ferrie is a Ph.D. student interested in utilizing geochemical behavior to research seismologic processes and paleoclimate reconstruction. Her research focuses on using boron adsorption and isotopic fractionation (1) as a fluid tracer in shallow subduction complexes and (2) as a proxy for paleoatmospheric CO2 reconstruction in paleosols. Nicole performs experimental work on both subducted rock from the Nankai Trough and...

Mielle Lee (Co-supervisor)
My research is driven by understanding the carbon cycle in karst ecosystems. I'm interested in learning how vegetation and water play a role in the subsurface to sequester carbon.

Riley Garrett (Co-supervisor)
Riley is currently pursuing an MS degree at the Jackson School of Geosciences. Her research focuses on carbon gas emissions and geochemical changes associated with permafrost thaw. She conducts experimental work to simulate a variety of warmer temperatures and quantifies the permafrost carbon dioxide and methane emissions along with the carbon isotope values using a GC-IRMS. With this data and...

Morgan Mellum (Supervisor)

Kiara Gomez, Ph.D., 2022 (Committee Member)
Jackson School of Geosciences

Evan Ramos, Ph.D., 2021 (Co-supervisor)
Department of Geosciences

Lily Serach, Ph.D., 2021 (Supervisor)
Department of Geosciences

Natasha Sekhon, Ph.D., 2021 (Co-supervisor)
Department of Geosciences

Lily Jaskcon, Ph.D., 2019 (Committee Member)

Peter Carlson, Ph.D., 2018 (Co-supervisor)

Sol Cooperdock, M.S., 2017 (Supervisor)

John Warden, Ph.D., 2016 (Co-supervisor)

Tim Charlton, M.S., 2016 (Co-supervisor)

Chris Cacciatore, M.S., 2016 (Supervisor)

Michael Patson, M.S., 2015 (Supervisor)

Brandon Okafor, M.S., 2014 (Supervisor)

Marlo Gawey, M.S., 2013 (Supervisor)

Lacey Pyle, M.S., 2012 (Supervisor)

Nate Meyer, M.S., 2012 (Supervisor)

Kyle Meyer, M.S., 2012 (Co-supervisor)

Year	Semester	Course
2024	Spring	GEO 476M	Aqueous Geochemistry
2024	Spring	GEO 387C	Aqueous Geochemistry
2023	Spring	GEO 387C	Aqueous Geochemistry
2023	Spring	GEO 391	Envirnmentl Isotope Geochem
2023	Spring	GEO 376E	Environmental Isotope Geochem
2023	Spring	GEO 476M	Aqueous Geochemistry
2022	Fall	GEO 401	Physical Geology
2022	Summer	GEO f376L	Field Meths In Groundwtr Hydrl
2022	Summer	GEO f382C	Groundwater Field Methods
2021	Fall	GEO 401	Physical Geology
2021	Spring	GEO 376E	Environmntl Isotope Geochem-Wb
2021	Spring	GEO 391	Envirnmentl Isotope Geochem-Wb
2020	Fall	GEO 401	Physical Geology
2020	Fall	GEO 401	Physical Geology-Wb
2019	Fall	GEO 401	Physical Geology
2019	Summer	GEO f660B	Field Geo-Tx/Nm/Co/Wy/Mt/Id/Ut
2019	Spring	GEO 376E	Environmental Isotope Geochem
2019	Spring	GEO 388H	Environmental Isotope Geochem
2018	Fall	GEO 401	Physical Geology
2018	Summer	GEO f660B	Field Geo-Tx/Nm/Co/Wy/Mt/Id/Ut
2018	Spring	GEO 191	Proposal Writing
2018	Spring	GEO 291	Asian Monsoon
2018	Spring	GEO 394	Rsch In Geological Sciences
2017	Fall	GEO 401	Physical Geology
2017	Fall	GEO 394	Rsch In Geological Sciences
2017	Spring	GEO 376E	Environmental Isotope Geochem
2017	Spring	GEO 388H	Environmental Isotope Geochem
2017	Spring	GEO 191	Proposal Writing
2017	Spring	GEO 394	Rsch In Geological Sciences
2016	Fall	GEO 394	Rsch In Geological Sciences
2016	Fall	GEO 401	Physical Geology
2016	Spring	GEO 191	Proposal Writing
2016	Spring	GEO 394	Rsch In Stbl Isotp Biogeochem
2015	Fall	GEO 394	Rsch In Geological Sciences
2015	Fall	GEO 401	Physical Geology
2015	Spring	GEO 376E	Environmental Isotope Geochem
2015	Spring	GEO 388H	Environmental Isotope Geochem
2015	Spring	GEO 191	Proposal Writing
2015	Spring	GEO 394	Rsch In Stbl Isotp Biogeochem
2014	Fall	GEO 394	Rsch In Stbl Isotp Biogeochem
2014	Fall	GEO 401	Physical Geology
2014	Spring	GEO 191	Proposal Writing
2014	Spring	GEO 394	Rsch In Stbl Isotp Biogeochem

Research Group Website