Periodic Reporting for period 4 - ARCHEIS (Understanding the onset and impact of Aquatic Resource Consumption in Human Evolution using novel Isotopic tracerS)
Reporting period: 2023-09-01 to 2025-02-28
The onset of the systematic consumption of marine resources is thought to mark a turning point for the hominin lineage. To date, this onset cannot be traced, since classic isotope markers are not preserved beyond 50 - 100 ky. Aquatic food products are essential in human nutrition as the main source of polyunsaturated fatty acids in hunter-gatherer diets. The exploitation of marine resources is also thought to have reduced human mobility and enhanced social and technological complexification. Systematic aquatic food consumption could well have been a distinctive feature of Homo sapiens species among his fellow hominins, and has been linked to the astonishing leap in human intelligence and conscience. Yet, this hypothesis is challenged by the existence of mollusk and marine mammal bone remains at Neandertal archeological sites. The question of past hominin diets has its role in modern society as its documentation reveals the variability of human diets and adaptive strategies through times, when we, ourselves, might have to adapt our diets for a more sustainable society. However, the main outcome of this study is a better knowledge of the interaction between human evolution and subsistence strategies.
Recent work demonstrated the sensitivity of Zn isotope composition in bioapatite, the mineral part of bones and teeth, to dietary Zn. By combining classic (C and N isotopes) and innovative techniques (CSIA-AA and bulk Zn isotopes); the ARCHEIS project aims at developing an isotopic tool capable to establish the onset of fish consumption relative to that of shellfish and link the introduction of marine food in hominin diets to their cultural and biological evolution. It investigates the dependence of δ66Zn on trophic level and marine food consumption, by establishing the isotope fractionation mechanisms during intestinal absorption and studying populations consuming aquatic food from different trophic levels: shellfish, fish and marine mammals. The project also addresses unsolved questions surrounding the disappearance of precolonial shell mounds of the Brazilian coast 2,000 y ago and the debate on fish consumption of prehistoric humans in Europe.
Recent work demonstrated the sensitivity of Zn isotope composition in bioapatite, the mineral part of bones and teeth, to dietary Zn. By combining classic (C and N isotopes) and innovative techniques (CSIA-AA and bulk Zn isotopes); the ARCHEIS project aims at developing an isotopic tool capable to establish the onset of fish consumption relative to that of shellfish and link the introduction of marine food in hominin diets to their cultural and biological evolution. It investigates the dependence of δ66Zn on trophic level and marine food consumption, by establishing the isotope fractionation mechanisms during intestinal absorption and studying populations consuming aquatic food from different trophic levels: shellfish, fish and marine mammals. The project also addresses unsolved questions surrounding the disappearance of precolonial shell mounds of the Brazilian coast 2,000 y ago and the debate on fish consumption of prehistoric humans in Europe.
Over 6 years, we documented Zn isotope variations in more than 180 animal species and 70 plant species, enhancing our understanding of how local environment, metabolism, and diet influence these ratios. Our research demonstrated the potential of δ66Zn to track the onset of frequent aquatic food consumption in human evolution, as well as other dietary habits.
Key findings include distinct differences between invertebrates and vertebrates, as well as between animals that consume whole prey and those that tear it apart. Thanks to P. Mejean’s work, we identified higher δ66Zn values in cereals and legumes compared to other plants, reinforcing the utility of δ66Zn in tracing the adoption of agriculture. Notably, Z. Moubtahij’s research on an Iberomaurusian population at the end of the Pleistocene revealed a diet rich in plants. She also demonstrated the absence of fish consumption among coastal Neolithic populations in North Morocco, similarly to earlier hunter-gatherers, thus showing a distinct pattern compared to Europe.
We published the first δ66Zn values for Pleistocene Neandertals and modern humans across four studies, showcasing the potential of Zn isotopes as dietary tracers, particularly in regions where traditional trophic proxies are not viable. Additionally, J. M. Cardoso’s research challenged the classic trophic level model by showing that, in Brazilian tropical food webs, carnivores do not follow the expected pattern of feeding on mammals. Another major discovery was the identification of Zn isotope ratios as a proxy for breastfeeding.
Collaborative controlled feeding experiments provided further insights into Zn isotope fractionation in vertebrates, demonstrating that:1) Zn isotope ratios in body tissues directly reflect the δ66Zn of consumed animal foods. 2) Fractionation patterns within mammalian and fish tissues are comparable.
We also documented seasonal variations in δ66Zn values in terrestrial mammal tissues. One particularly striking application of our research was the combined use of Zn and O isotope ratios in horse teeth, which revealed that modern humans reached high European latitudes during a cold episode of the Pleistocene—challenging previous assumptions.
By integrating δ66Zn with other isotope proxies and Bayesian mixing models, we reconstructed the diverse diets of precolonial populations in Brazil, including their consumption of shellfish. This contributed to the longstanding debate on whether the shells used to build sambaquis also played a significant role in the diet of these populations. Another innovative development was the use of machine learning to construct an isoscape addressing inconsistencies in sulfur isotope ratios in Europe. This led to the creation of triple Sr-O-S isoscapes, which have since become a key tool for determining individual geographic provenance.
Our research on freshwater seals, along with studies on dolphins and other marine mammals, clarified the relationship between trophic level and diet. The work of G. Le Bras, combining Zn isotope analysis with CSIA-AA and research from the BAP led by A. Weber, confirmed distinct δ66Zn values between prehistoric consumers of game fish and those consuming both game fish and seals.
We also addressed key analytical challenges to enable less destructive analyses while preserving valuable samples. Key achievements included:1)The use of a micromill to sample small teeth.2)The development of a protocol allowing the combined analysis of Ca, Sr, and Zn stable isotopes from a single sample.
Additionally, B. Fuller and C. Lagane established CSIA-AA analysis at GET, making our lab the fifth worldwide—and the first in France—to develop this approach for archaeology. We fostered new collaborations, particularly with genomic experts and specialists working on Neandertal and modern human samples from tropical and arid regions.
Zn isotope ratios are now recognized as a key tool for reconstructing ancient diets, especially in terrestrial contexts where protein preservation is limited. Many insights from the past 6 years continue to shape the field, with numerous publications forthcoming. Notably, our long-term collaboration with R. Colleter contributed to a study tracing dietary inequality related to gender over 10,000 years in Europe.
The results of this research have been published in 27 articles, 2 PhD dissertations, 23 conference presentations, and 3 posters, with 10 additional publications currently under review or in preparation. Our findings have also been disseminated through radio interviews and public outreach articles.
Key findings include distinct differences between invertebrates and vertebrates, as well as between animals that consume whole prey and those that tear it apart. Thanks to P. Mejean’s work, we identified higher δ66Zn values in cereals and legumes compared to other plants, reinforcing the utility of δ66Zn in tracing the adoption of agriculture. Notably, Z. Moubtahij’s research on an Iberomaurusian population at the end of the Pleistocene revealed a diet rich in plants. She also demonstrated the absence of fish consumption among coastal Neolithic populations in North Morocco, similarly to earlier hunter-gatherers, thus showing a distinct pattern compared to Europe.
We published the first δ66Zn values for Pleistocene Neandertals and modern humans across four studies, showcasing the potential of Zn isotopes as dietary tracers, particularly in regions where traditional trophic proxies are not viable. Additionally, J. M. Cardoso’s research challenged the classic trophic level model by showing that, in Brazilian tropical food webs, carnivores do not follow the expected pattern of feeding on mammals. Another major discovery was the identification of Zn isotope ratios as a proxy for breastfeeding.
Collaborative controlled feeding experiments provided further insights into Zn isotope fractionation in vertebrates, demonstrating that:1) Zn isotope ratios in body tissues directly reflect the δ66Zn of consumed animal foods. 2) Fractionation patterns within mammalian and fish tissues are comparable.
We also documented seasonal variations in δ66Zn values in terrestrial mammal tissues. One particularly striking application of our research was the combined use of Zn and O isotope ratios in horse teeth, which revealed that modern humans reached high European latitudes during a cold episode of the Pleistocene—challenging previous assumptions.
By integrating δ66Zn with other isotope proxies and Bayesian mixing models, we reconstructed the diverse diets of precolonial populations in Brazil, including their consumption of shellfish. This contributed to the longstanding debate on whether the shells used to build sambaquis also played a significant role in the diet of these populations. Another innovative development was the use of machine learning to construct an isoscape addressing inconsistencies in sulfur isotope ratios in Europe. This led to the creation of triple Sr-O-S isoscapes, which have since become a key tool for determining individual geographic provenance.
Our research on freshwater seals, along with studies on dolphins and other marine mammals, clarified the relationship between trophic level and diet. The work of G. Le Bras, combining Zn isotope analysis with CSIA-AA and research from the BAP led by A. Weber, confirmed distinct δ66Zn values between prehistoric consumers of game fish and those consuming both game fish and seals.
We also addressed key analytical challenges to enable less destructive analyses while preserving valuable samples. Key achievements included:1)The use of a micromill to sample small teeth.2)The development of a protocol allowing the combined analysis of Ca, Sr, and Zn stable isotopes from a single sample.
Additionally, B. Fuller and C. Lagane established CSIA-AA analysis at GET, making our lab the fifth worldwide—and the first in France—to develop this approach for archaeology. We fostered new collaborations, particularly with genomic experts and specialists working on Neandertal and modern human samples from tropical and arid regions.
Zn isotope ratios are now recognized as a key tool for reconstructing ancient diets, especially in terrestrial contexts where protein preservation is limited. Many insights from the past 6 years continue to shape the field, with numerous publications forthcoming. Notably, our long-term collaboration with R. Colleter contributed to a study tracing dietary inequality related to gender over 10,000 years in Europe.
The results of this research have been published in 27 articles, 2 PhD dissertations, 23 conference presentations, and 3 posters, with 10 additional publications currently under review or in preparation. Our findings have also been disseminated through radio interviews and public outreach articles.
The ARCHEIS project has established the robustness of Zn isotopes in archaeology, demonstrating that δ66Zn is a reliable trophic level marker applicable over millions of years. It has been used to document the diet of Pleistocene Neandertals and modern humans.
Our work has also documented the variability of δ66Zn across a wide range of food sources, proving its value in characterizing cereal-rich diets. Another major advancement is the multiproxy approach which successfully detects shellfish consumption. Additionally, the development of the triple isoscape has emerged as a key tool with significant impact for the research community.
Our work has also documented the variability of δ66Zn across a wide range of food sources, proving its value in characterizing cereal-rich diets. Another major advancement is the multiproxy approach which successfully detects shellfish consumption. Additionally, the development of the triple isoscape has emerged as a key tool with significant impact for the research community.