Collaborative Research: Coupling Archaeological shell and novel isotope approaches to reconstruct impact of nearshore productivity change

考古学的一个核心问题是了解人类如何受到过去环境变化的影响，以及他们如何反过来积极地塑造周围的生态系统和生物。为了探索这些问题，一些考古学家试图了解人口稠密的沿海地区等级制社会政治制度的起源。通过对人工制品、村庄结构、人类生存和高精度气候记录的分析，考古学家们对假设的海洋生产力下降和延长的El Niño条件与延长的干旱的影响进行了激烈的辩论。即使在世界上具有异常高分辨率的海洋气候记录的背景下，解释过去的气候数据也可能具有难以置信的挑战性，因为整个地区的表面海洋学变化很大。该项目为一些本科生和研究生，特别是历史上代表性不足的群体和土著社区的成员提供培训机会，并将支持各种各样的外联活动。这项研究试图了解文化复杂性何时以及为何在这样一个地区出现，以及它与过去气候变化之间的任何联系。为了解决这些问题，研究人员利用了从考古遗址获得的贝壳中新的分子/同位素（氨基酸的化合物特异性同位素或CSI-AA）的分析。CSI-AA在考古贝壳中保存完好，可以直接记录当地海洋学中与气候相关的变化，包括营养源、基线初级产量、营养结构和藻类群落组成。这一分析为过去气候变化和环境生产力提供了一个新的、高度本地化的来源，以帮助解决核心研究问题。该项目是CSI-AA分析在加利福尼亚广泛的社会、政治和文化发展的第一个系统的考古应用，将对世界各地过去环境变化的考古研究产生深远的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

A central issue in archaeology is understanding how people were influenced by past environmental change and how they, in turn, actively shaped ecosystems and organisms around them. To explore those questions, some archaeologists have attempted to understand the origins of hierarchical sociopolitical systems among the densely populated coastal regions. Drawing on the analysis of artifacts, village structure, human subsistence, and high-precision climate records, archaeologists have rigorously debated the impact of hypothesized declines in marine productivity and extended El Niño conditions vs. extended drought. Even in contexts with exceptionally high-resolution marine climate records in the world, interpreting past climatic data can be incredibly challenging where surface oceanography across the region is highly variable. This project provides training opportunities for several undergraduate and graduate students, especially members of historically under-represented groups and Indigenous communities, and will support a wide variety of outreach activities.This research seeks to understand when and why cultural complexity arose along one such region and any links it may have to past changes in climate. To address these issues, the researchers draw on the analysis of novel molecular/isotopes (compound-specific isotopes of amino acids or CSI-AA) in shells obtained from archaeological sites. CSI-AA is well preserved in archaeological shell and can directly record climate-linked shifts in local oceanography, including nutrient sources, baseline primary production, trophic structure, and algal community composition. This analysis offers a new, highly localized source of past climate variation and environmental productivity to help address the central research questions. This project is the first systematic archeological application of CSI-AA analyses addressing broad social, political, and cultural developments in California and will have far reaching implications for archaeological research on past environmental change around the world.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.