Stable Isotope Insights into Shellfish Consumption and Transport

University Of California-Davis, Davis CA

Investigators

Abstract

In partnership with several tribal organizations in California, this research examines the role of shellfish in the diets of pre-contact Native Californians, and by extension, the maintenance and evolution of social networks and organizations. Shellfish is common in archaeological sites on San Francisco Bay, and judging by the huge shellmounds that formed up to several millenia ago, was a major dietary staple for people living in this region. Somewhat surprising, however, are large amounts of shellfish at inland archaeological sites that are up to dozens of kilometers from the bay. These food resources would have been carried on the backs of people, without means of refrigeration, prompting the question, what role did shellfish play in inland subsistence economies? Were they staples in the diet, important but minor sources of nutrients such as iodine, fallback/starvation foods, or part of ritual or feasting events? The project will provide information on human ecological adaptation and organization of trade networking. It will also create and enhance educational and training opportunities for students, develop a museum display open to the public, and enhance collaboration between archaeologists and particular descendant groups. The human skeleton is synthesized from the foods we eat. Relative to terrestrial foods, marine resources contain distinctive chemical and stable isotopic signatures. These become embedded in growing skeletal tissues, including teeth. The research team will take advantage of advances in mass spectrometry that facilitate analysis of small micro-samples of dentinal collagen and shell carbonate. Micro-sampling of teeth and shells will allow them to trace the transportation and consumption of shellfish across different people, different seasons, and across different time scales within a person’s life. The new data will allow the team to test particular models about the role that shellfish played in human diets, across a range of distances from San Francisco Bay. Together, the research will provide new insights into the diversity of human ecological adaptations within a complex environment, the nature of inter-annual and inter-individual variation in ancient human diets, the role of micro- and macro-nutrients in diets, and the development of social networks in providing access to estuarine resources in more inland settings. 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.