Arnold Geochemistry Lab

Active projects

Fecal Stanols and Maya Population Trends

PA State System of Higher Education (PASSHE) · 2026–present

We are using concentrations of fecal biomarkers in lake sediments from the Yucatán to reconstruct population histories at Maya sites. This work is in conjunction with PIs from Auburn University and the University of Florida.

Atmospheric Deposition of Microplastics

Multiple college and university level grants · 2026–present

In this project, we are investigating rates of atmospheric microplastic deposition. We are also quantifying microplastics on leaves and classifying their polymer types, since leaves can act as “interceptors” that capture microplastics from the air.

Hydroclimate Variability at Petén Itzá, Guatemala

Paleo Perspectives on Climate Change (P2C2) · 2021–present

We are working with colleagues to use hydrogen isotopes in leaf wax lipids to reconstruct precipitation in the tropics from ca. 450,000 BP to present.

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Recent publications

• Mattie, C., Ashman, I., Fork, M., Arnold, T.E. (2026). Seasonality and maximum wind gusts correlate with microplastic concentrations in a freshwater stream system. Environmental Monitoring and Assessment, 198, 1173.
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• Arnold, T.E., Lei, Y., Strong, D.J., Hilliker, J., Caballero, M., Correa-Metrio, A., Pérez, L., Schwalb, A., Macario-González, L., Cohuo, S., Lozano-García, S., Ortega-Guerrero, B., Werne, J.P. (2026). Biosynthetic fractionation drives leaf wax hydrogen isotope variability across Mexico and Central America. Organic Geochemistry, 105259.
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• Arnold, T.E., Hilliker, J.L., Werne, J.P., Thompson, A.J. (2026). Atmospheric transmission of temperature and precipitation change in Florida during North Atlantic Heinrich events. Paleoceanography and Paleoclimatology, 41, e2025PA005143.
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• Eusebio, M.S., Piper, P.J., Arnold, T.E., Krigbaum, J. (2023). Possible leafy vegetables in prehistoric southern Vietnamese cuisine with a distinctive biomolecular profile. Journal of Archaeological Science: Reports, 47, 103741.
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• Oyo-Ita, I.O., Sam, E.S., Oyo-Ita, O.E., Arnold, T.E., Inyang, D.O., Werne, J.P. (2023). Stable carbon isotope and n-alkane distributions in sediment cores from saline and freshwater Gabu lakes, southeast Nigeria: environmental implications. Environmental Earth Sciences, 82, 422.

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