Using lake sediments to reconstruct the indigenous occupation of the Kukulek archeological site and the impact of recent climate change on freshwater ecosystems at St. Lawrence Island, Alaska

Changing weather patterns during the late-1870s impaired winter hunting success and devastated the historical village of Kukulek at St. Lawrence Island (Alaska), resulting in famine and abandonment of the site. Here, we use dated sediment cores from two freshwater ponds within the catchment of the Kukulek archeological site to track the history of occupation including the 1878–1880 famine, with comparisons to two reference ponds not affected by direct human activity. The study pond nearest the archeological site recorded the highest values of stable nitrogen isotopes (δ 15 N) as well as eutrophic diatom assemblages, which reflect fertilization from nutrients released from marine mammals butchered onshore. The onset of the eutrophication signal may be related to catchment disturbances during the abandonment of the village in 1880, and from the archeological excavation in the mid-1930s. These physical disturbances occurred during a warming period when thawing permafrost and the release of nutrients from previously frozen meat caches and marine mammal remains may have augmented pond fertilization. In the reference ponds, late 19th century climate warming appears to be the primary driver of limnological change with chironomids shifting to warmer-adapted assemblages and diatom taxa reflecting increased habitat complexity that is often documented with longer growing seasons. The information from the reference ponds underscores the importance of considering climate when tracking cultural eutrophication in the Arctic and elsewhere.