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Limpets pointing to climate and human behaviour during prehistory

The UPV/EHU-University of the Basque Country is using the shells of marine molluscs to work on the reconstruction of climate and human behaviour during prehistory

  • Research

First publication date: 16/12/2020

Asier García-Escárzaga using a micromill machine to obtain samples throughout shell growth
Asier García-Escárzaga using a micromill machine to obtain samples throughout shell growth. Photo: Asier García-Escárzaga. UPV/EHU.

A study conducted by researchers in the department of Geography, Prehistory and Archaeology at the UPV/EHU in collaboration with the University of Cantabria and the Max Planck Institute shows that limpets of the Patella depressa species are a high-resolution climate indicator with significant implications for future archaeological and palaeoclimatic studies.

Analyses of stable oxygen isotope (δδ18O) ratios in marine mollusc shells make it possible to reconstruct past oceanographic conditions as well as the way of life of human populations in prehistoric times. However, before analysing the archaeological samples, it is necessary to analyse current shells to determine whether the selected species is a suitable indicator of climate conditions during growth. Despite the fact that the ‘Patella depressa’ species is one of the most widespread ones in the archaeological record of the Holocene all along the Atlantic coast of Europe, it had not been tested as an indicator for reconstructing sea temperature.

A study, co-led by the UPV/EHU’s Asier García-Escárzaga in collaboration with researchers from the Max Planck Institute and the University of Cantabria, has shown for the first time that the ‘Patella depressa’ species is a suitable climate indicator. This research, published in the international ‘Palaeogeography, Palaeoclimatology, Palaeoecology’ journal combines a study of the growth patterns of the shells with an analysis of stable oxygen isotopes.

Climate changes recorded during shell growth

The authors point out that sea temperatures reconstructed using isotopic values of modern samples accurately reflect sea temperature variations during the lifetime of the specimens analysed. These results confirm that the analyses of stable oxygen isotopes in shells of the ‘Patella depressa’ species are a wonderful indicator of present and past climate conditions.

This pioneering research also has important implications for future palaeoclimatic and archaeological studies. Specifically, the analysis of archaeological shells will make it possible to determine the exploitation patterns of the marine environment by human populations during prehistory and the impact that the various climate changes taking place in the past exerted on these groups.

Additional information

Asier García-Escárzaga is a researcher at the UPV/EHU thanks to the Basque Government post-doctoral programme. Right now, he is at the Max Planck Institute for the Science of Human History (Germany) where he is on a post-doctoral stay provided for in the funding of the said programme. Once he has completed his two-year international stay, in 2021 he will be joining the Department of Geography, Pre-history and Archaeology at the UPV/EHU's Faculty of Arts, within the framework of the Prehistoria/Historiaurrea research group. The research project that this study is a part of (Palaeoshells) is funded by the Spanish Ministry of the Economy and Competitiveness (MINECO), and one of its main aims is to reconstruct exploitation patterns of the coastal resources during Prehistory in the Bay of Biscay.

Bibliographic reference