by Mary Caperton Morton Friday, October 13, 2017
Today, Finland’s Northern Ostrobothnia region is one of the northernmost places in Europe that can support agriculture. But how this region fared during the Little Ice Age — a period of globally cooler temperatures that lasted roughly from A.D. 1300 to 1850 — is unknown. Scientists assume the climatic cooling would have adversely affected food supplies. Now, however, the discovery of a mysterious medieval cemetery in northern Finland dating to the middle of the Little Ice Age is offering clues that the inhabitants were well fed and well suited to the northern clime.
The cemetery, located near the Northern Ostrobothnian town of Iin Hamina, was unearthed in 2009 during a pipeline construction project. To date, excavations have uncovered remains from nearly 300 people dating from the 15th and 16th centuries, making this the largest medieval site studied in Finland. Much about the ethnicities and lifestyles of these people remains a mystery, says Maria Lahtinen, an archaeologist at the University of Helsinki. “Finland has a very short written history, and this cemetery is not mentioned in historical texts or marked on historical maps. We don’t know if there was a central village or if people were widely scattered around this area.”
Additionally, little is known about the medieval history of agriculture in this region, although episodes of famine due to crop failures have occurred as recently as the mid-19th century. Iin Hamina is situated near the Gulf of Bothnia, an offshoot of the Baltic Sea, so fish were likely a major part of the inhabitants' diets. A cow bone found mixed in with the burial fill may indicate that they raised livestock, Lahtinen notes. “There was probably some form of animal husbandry, but the scale and importance are unknown. We don’t know exactly what they were eating or what they were growing.”
Fortunately, some of the human remains — specifically teeth — are offering a few clues. In a new study, published in the journal Radiocarbon, Lahtinen analyzed hydrogen and carbon isotope compositions preserved in the teeth of 11 individuals. “Teeth record a lifetime of nutrition and can tell us a lot about both diet and lifestyle,” she says. Variations in isotope compositions in the successive layers of the teeth reflect changes in diet over annual timescales. “This can tell us about longer-term episodes of starvation or hardship that occurred anytime from early childhood into adulthood.”
Despite the extreme northern setting and the potential added chill from the Little Ice Age, the nutritional needs of the people buried in the cemetery appear to have been met throughout their lives. “Much to my surprise, we didn’t see any evidence for nutritional stress in 10 out of 11 people,” Lahtinen says. The teeth from the 10 individuals “didn’t show any of the typical starvation signals,” she says, and “it seems they were well adapted to thrive in their northern environment.” The 11th sample was an outlier, she adds: “It looks like that person had a completely different diet from the others.” Future work at Iin Hamina could involve pollen and microfossil studies to better understand what kind of crops people may have grown there, Lahtinen says.
The lack of evidence for famine may also be due to regional variability during the Little Ice Age, when different places cooled to different extents at different times, says Michael Mann, a climatologist at Penn State University who was not involved in the new study. “When it was relatively warm or relatively cold is highly regionally variable,” he says. “There is ample evidence indicating that regional climate variations did indeed impact agriculture in northern Europe, but the precise details depend on the region and period. There is no simple one-size-fits-all explanation.”
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