B.S. Chemistry with General Honors, University of Chicago, 2014
B.S. Geophysical Sciences with Honors, University of Chicago, 2014
- Tech F483
I use stable isotopes to understand past climate change at local and global scales. The stable isotope abundances in minerals are good records of Earth’s environmental history; isotope records preserve information about atmospheric composition, temperature, biological metabolisms, and weathering processes.
During my PhD at Harvard University, I interpreted the history of atmospheric pO2 levels by analyzing the stable oxygen isotope (17O and 18O) abundances of marine sulfate minerals over the last 542 million years. Our new record of marine sulfate 17O indicates that pO2 levels transitioned to modern levels around the Devonian Era (~400 million years ago), coincident with the rise in abundance of land plants.
At Northwestern, my work in the Jacobson lab will build on our understanding of ocean anoxic events in the past using the calcium and strontium isotope systems.
Outside of lab, I enjoy experimenting in the kitchen and exploring the outdoors.
Waldeck, A. R.*, Olson, H. C.*, Weiqi, Y., Blättler, C.L., Paytan, A., Hodell, D., & Johnston, D.T. "Calibrating the triple oxygen isotope composition of evaporite minerals as a proxy for marine sulfate." Earth and Planetary Science Letters, in press.
Waldeck, A. R., Cowie, B. R., Bertran, E., Wing, B. A., Halevy, I., & Johnston, D. T. "Deciphering the atmospheric signal in marine sulfate oxygen isotope composition." Earth and Planetary Science Letters 522 (2019): 12-19.