Study: King Midas' feast offered golden opportunity for fungi
WEST LAFAYETTE, Ind. The food buried with King Midas around 700 B.C., along with the king himself, may have fueled a feast for a generally benign type of fungus that led to extensive deterioration of the king's tomb, a new study shows.
Timothy Filley, assistant professor of biogeochemistry at Purdue University, led a study that combined stable nitrogen isotope analysis and microscopy of wood samples from the tomb to gather information on the king's diet and determine the nutrient sources for the fungi that destroyed much of the contents of the tomb and human remains.
The findings, published in the Oct. 30 issue of the Proceedings of the National Academy of Sciences, may explain why many artifacts within the tomb have deteriorated, despite the fact they were constructed of decay-resistant wood, Filley says.
"The structural and chemical signatures of the decay, which is heaviest where the body was laid and on the tabletops surrounding the coffin, indicates that the fungus was fueled by nitrogen from the king's body and food sources left in the tomb," Filley says.
"Our results account for the tenuous nature of archeological wood in the tomb and demonstrate the fine balance that must be maintained between the environment, nutrient supply and microbial community to permit preservation," he says.
The samples Filley studied came from Tumulus Midas Mound at Gordion, Turkey, thought to be the tomb of the Phrygian King Midas. Earlier analysis of the coffin, furniture and tomb structure by co-authors Robert Blanchette and Elizabeth Simpson had shown that the primary cause of degradation was a soft-rot fungus, which generally does not cause extensive damage to wood.
"Though environmental conditions within the tomb over the past 2,700 years were fairly dry, alkaline water seeped through the limestone overburden of the mound into the buried wooden tomb, creating ideal conditions for this distinct type of fungi to flourish," Filley says. "The fungus, without competition from other wood decomposing microbes, was able to feed off the nitrogen sources found in the tomb."
To determine the nutrient sources that fed the fungus, Filley analyzed stable nitrogen isotopes found in the wood and other artifacts from the tomb. Isotopes are forms of an element that contain slight variations in their neutron counts but have the same number of protons.
The test used by Filley and colleagues, which included Marilyn Fogel of the Carnegie Institution of Washington, was designed to detect trace amounts of two forms of nitrogen: 14-N, which accounts for most of the nitrogen found in nature, and 15-N, a heavier form of nitrogen.
Filley says the extremely high levels of 15-N found in the wood of the coffin, as well as the floor boards around the coffin, suggest that the king's body served as a primary source of nitrogen for the wood-decomposing fungi. In addition, the findings indicate that the king with the golden touch also had a penchant for meat.
"While all animals contain small amounts of the heavier form of nitrogen, creatures higher on the food chain contain greater amounts," he says. "The high levels of 15-N found in the wood around the coffin suggest a diet rich in meat."
Food from the funerary meal which consisted primarily of barbecued meats also provided nourishment for the fungi, evidenced by the extensive deterioration of the tabletops on which food was placed, Filley says.
"How long the fungal community feasted upon the body of the king is a matter for speculation," he says. "But the extensive decay found throughout the huge cedar and pine timbers suggests the soft-rot fungus may have lingered in the tomb for centuries or possibly millennia."
The findings may suggest ways to arrest further deterioration, Filley says.
"Identifying and tracking the nutrient source of the microbes and relating it to the chemistry of wood decay may suggest ways to thwart fungal growth at existing historical sites," he says.
Currently, Filley and Blanchette are working on microbial decomposition processes in the Canadian Arctic where soft-rot fungi are quite active. As a pilot study, they traveled to the High Arctic this past summer to collect wood samples from the historic camp established by American explorer Adolphus Greely, who set out to lead a military expedition to the North Pole in 1882. The voyage ended in disaster when supply ships failed to reach his group.
Filley and Blanchette plan to continue their research in the Arctic next summer.
Collaborating with Filley were Blanchette of the University of Minnesota, Fogel, and Simpson of the Bard Graduate Center for Studies in the Decorative Arts in New York.
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Nitrogen cycling by wood decomposing soft-rot fungi in the "King Midas tomb," Gordion, Turkey
Timothy Filley, Robert Blanchette, Elizabeth Simpson, and Marilyn Fogel
Archaeological wood in ancient tombs is found usually with extensive degradation, limiting what can be learned about the diet, environment, health, and cultural practices of the tomb builders and occupants. Within Tumulus Midas Mound at Gordion, Turkey, thought to be the tomb of the Phrygian King Midas of the 8th century B.C., we applied a stable nitrogen isotope test to infer the paleodiet of the king and determine the nitrogen sources for the fungal community that decomposed the wooden tomb, cultural objects, and human remains. Here we show through analysis of the coffin, furniture, and wooden tomb structure that the principal degrader, a soft-rot fungus, mobilized the king's highly 15N-enriched nutrients, values indicative of a diet rich in meat, to decay wood throughout the tomb. It is also evident from the [delta] 15N values of the degraded wood that the nitrogen needed for the decay of many of the artifacts in the tomb came from multiple sources, mobilized at potentially different episodes of decay. The redistribution of nutrients by the fungus was restricted by constraints imposed by the cellular structure of the different wood materials that apparently were used intentionally in the construction to minimize decay.