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Isotopes: Science's Common Courtesy
FROM TRACKING THE ROUTES OF WATER THROUGHOUT THE WEST TO DETERMINING THE LEVELS OF CARBON IN THE PALEOCENE, GABRIEL BOWEN’S RESEARCH INTO ISOTOPES EXTENDS INTO A VARIETY OF CRITICAL RESEARCH PATHS.
“One of the really cool things about isotope geochemistry is that it really crosses disciplinary boundaries,” Bowen says. “It’s a subfield that grew out of earth science, geology, and geochemistry, but it’s useful in everything from forensic science to water research to planetary science.”
Bowen grew up in rural Michigan and spent his childhood outdoors, which grew his love of nature and the earth. He received his bachelor’s in geology at the University of Michigan and went to UC Santa Cruz for a PhD in earth science. Bowen came to the U as a post doctoral researcher before joining Purdue University as a faculty member for seven years. He returned to the U through the Global Change and Sustainability Center and is now Professor of Geology & Geophysics and Co-Director of the Stable Isotope Facility for Environmental Research (SIRFER).
Recipient of this year's College of Science Excellence in Research Award, Bowen founded the Spatio-Temporal Isotope Analytics (SPATIAL) Lab, which uses stable isotope techniques to look at a lot of different areas of application of isotope geochemistry. “Isotope science has been kind of limited by our ability to make measurements,” says Bowen.
The SPATIAL group has pushed forward uniting isotope geoscience with data science, which helps facilitate sharing within and between fields of study. These data can then be leveraged to tackle bigger systems questions, including reconstructing Earth’s climate through its geologic past. This allows researchers to see changes in climate, ecosystems, and biogeochemical cycles, which can then be compared to modern day.
CONTEXTUALIZING CURRENT AND FUTURE TRENDS
“The Earth’s been through a lot,” Bowen says. “There’s a lot of context that shows how unusual what’s happening right now is. We’re pushing the climate system and carbon cycle much faster than it’s ever gone at any point in the geologic record.” Bowen works with an international community of scientists whose initial study, published in November in the journal Science, has reconstructed CO2 concentrations going back through the Cenozoic, the era that began with the demise of dinosaurs and the rise of mammals 66 million years ago.
But this record does not extend very deep into the geologic past. To go deeper, Bowen says, “you have to rely on indirect evidence, what we call proxies.” One of those proxies are isotopes in minerals, the morphology of fossilized leaves and other lines of geological evidence that reflect atmospheric chemistry. Having a reliable map of past CO2 levels could help scientists more accurately predict what future climates may look like.
SOURCES OF WATER
Isotopes also help the SPATIAL group study how natural cycles operate today, such as the water cycle. Additionally, they also study spatial conductivity, or movement of things on the Earth’s surface, such as water, people, plants, and products. Bowen looks at where plants are getting water from in the subsurface of the Earth, which can show the stability of water supply within a community and help predict how water resources will change due to climate change.
“There’s an intimate coupling between the physical and biological processes that constitute a system,” Bowen says. “Isotopes are a common currency. The elements and isotopes that go through the water cycle or rock cycle are the same ones that go into an elephant or ponderosa pine. We can really bridge the gap and understand the connection across these spheres.”
Bowen’s climate change research includes tracking the sources of water, such as where water originates before it makes its way to southern California. The isotopes of water in the Imperial Valley in California look more like isotopes in Colorado water than in water elsewhere in southern California. Most of the Imperial Valley water is irrigation water diverted from the Colorado River. The irrigation water becomes wastewater from irrigation because of overwatering, and then it enters the groundwater. This has implications when agricultural runoff affects groundwater, as it could contain pesticides and other chemicals used in agricultural work.
The SPATIAL lab runs an annual summer course for graduate students, which provides training and experience in large-scale, dataintensive, geochemically oriented research. The course consists of a discussion and lecture in the morning, delivered by specialists in the field. Laboratory experiences introduce new techniques and hands-on learning.
“We live in a pretty amazing place for geology,” Gabriel Bowen says. He appreciates the geology of Utah from the air, as an amateur pilot. He flies a Cessna 182, mostly for geology sightseeing. He also participates in charity flying, taking people around Antelope Island for sightseeing of the Great Salt Lake. “I try to take my scientist and artist friends out to see things from a different perspective.” <
