How sea spray blurs our view of the past

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It is not only during severe storms, such as this one in October 2023, that sea spray is transported inland by the wind. Its influence on the isotope ratios of organic archaeological finds can extend up to 100 kilometres inland. | Quelle: Jan Steffen | Copyright: Cluster ROOTS | Download

Hinweis zur Verwendung von Bildmaterial: Die Verwendung des Bildmaterials zur Pressemitteilung ist bei Nennung der Quelle vergütungsfrei gestattet. Das Bildmaterial darf nur in Zusammenhang mit dem Inhalt dieser Pressemitteilung verwendet werden. Falls Sie das Bild in höherer Auflösung benötigen oder Rückfragen zur Weiterverwendung haben, wenden Sie sich bitte direkt an die Pressestelle, die es veröffentlicht hat.

Dr. Andrea Göhring works at the Leibniz Laboratory for Age Determination and Isotope Research at Kiel University | Quelle: Jürgen Haacks | Copyright: Kiel University | Download

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The origin and habits of prehistoric people, past environmental conditions or the age of archaeological samples – researchers can reconstruct all of this by determining the ratios of certain stable isotopes in bones, teeth or other organic remains. However, the interpretation of measurement results can be misleading if inadequately understood factors have affected the isotope ratios in the samples. “In order to obtain correct results in our analyses, we need to know all the additional influences, for example, the impact of sea spray on the coastal environment,” says Dr. Andrea Göhring from Kiel University.

The biological anthropologist is now leading an Emmy Noether Junior Research Group at Kiel University, funded by the German Research Foundation (DFG), which is focusing on this typical source of error in isotope analyses. Over a period of six years, Andrea Göhring will receive approximately 1.9 million euros for her research on the effect of sea spray. The interdisciplinary project builds a bridge between Kiel Marine Science (KMS), the marine priority research area of Kiel University, and the research of the Excellence Cluster ROOTS on the relationship between humans and the environment in the past.

Sea spray alters isotope ratios on land

“The interpretation of isotope analyses is used to date archaeological samples or to reconstruct past environmental conditions. However, the isotope ratios on land and in the sea are different,” reports Andrea Göhring, explaining the background of the project. Wind and waves constantly generate aerosols over the sea, which contain organic and inorganic compounds. They reach the land via the air and are deposited there. Plants, animals and humans absorb them. This changes the isotope ratios in their organisms. “This does not just affect the coastal area, but also up to 100 kilometres inland, depending on the location and the wind,” states Dr. Göhring.

However, the extent and variability of the sea spray effect are relatively unknown and cannot yet be reliably corrected in respective analyses. To change this, Andrea Göhring and her team will first investigate the sea spray effect in the isotope signature of plants and mammals currently living in the North Sea and the Baltic Sea.

Experiments provide information on current sea spray effects

Among other things, the team is generating a sea spray effect under controlled conditions in the greenhouse and is investigating the effects of sea spray on the isotope ratios in sheep’s wool. “This allows us to determine the magnitude of the locally expected sea spray effect for different isotope systems,” says the researcher. The results of these and other studies are then incorporated into model calculations. Andrea Göhring is working closely with the Department of Computer Science at Kiel University to evaluate the resulting data using the latest data mining methods. For example, the team will use archaeobotanical samples to determine changes in the extent of sea spray as a result of climate change. Andrea Göhring’s group will produce isotope maps for the North Sea and Baltic Sea coasts and apply the results to archaeological finds.

A sharper picture of past worlds

“Up to now, sea spray has partially distorted or at least clouded our view of the past in coastal regions. We want to provide researchers with tools to reliably correct the effect of sea spray when analysing isotopes in archaeological samples. This will also sharpen our view of the past,” remarks Andrea Göhring, summarising the goals of her project.
“We warmly congratulate Andrea Göhring on this great success with the DFG and are delighted that her project is based at Kiel University. Her research will provide fundamental insights into two important research areas at the university – marine research and the study of the human past. This shows once again that Kiel University is an inspiring academic environment for interdisciplinary science,” said CAU Vice President Professor Dr. Ralph Schneider.

Wissenschaftlicher Ansprechpartner:
Dr. Andrea Göhring
Leibniz Laboratory for Radiometric Dating and Stable Isotope Research
Kiel University
agoehring@leibniz.uni-kiel.de

Weitere Informationen:
https://www.uni-kiel.de/en/cluster-roots Cluster of Excellence ROOTS
https://www.uni-kiel.de/en/research/priority-research-areas/kiel-marine-science Priority Research Area Kiel Marine Science (KMS) at Kiel University