Varenka Lorenzi, Ph.D. - US grants

This project explores the limitations and potential of stanol biomarkers in archaeological research. Stanols are a group of molecules produced during food digestion. The combination of chemicals produced is unique to different organisms, with humans producing a significant amount of the molecule, coprostanol. This signature should allow researchers to differentiate the contribution of humans in the environment. The analysis of these chemicals in ponds, lakes, wetlands and soils is a new and promising geoarchaeological technique for determining human presence on past landscapes. Moreover, changes in the amount of stanols over time allows investigations of population changes. Population events, such as migration episodes, site abandonment, and disease and warfare, are important to understanding regional histories, but traditional demographic approaches frequently rely on historical documentation and archaeological excavation. Stanol analysis is a relatively noninvasive technique that is independent of the historical record and applicable in numerous archaeological and temporal settings. Additionally, the method can be performed alongside paleoenvironmental analyses to directly study human-environmental relations in the past. Despite the method’s promise, its limitations have not been fully explored and a systematic analysis of the usefulness of stanol molecules in archaeological research is needed to ensure reproducible and high-impact results. The project will generate a stanol database that will assist environmental scientists who study contamination in modern waters. This funding supports multidisciplinary training of students at the high school, undergraduate, and postgraduate levels.

The research team's multifaceted project seeks to 1) expand the number of documented stanol suites for animals that may be present in ancient human environs and to determine if these animals produce specific stanol molecules in quantities that may interfere with a human signal, 2) determine if compound-specific isotope (CSI) values of stanol molecules can be used to identify dietary changes in ancient populations, and 3) study the factors that affect stanol mobility and preservation in sediments. The research team, composed of geochemistry, biochemistry, and geoarchaeology specialists, employs samples from a targeted selection of zoo animals that have not been previously tested for stanol content.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.