Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.

The data contained herein are from eight sediment multicores and three piston sediment cores with accompanying gravity/trigger sediment cores spanning the Lake Superior basin. The multicores were sampled at high resolution encompassing the most recent ca. 200 years and the gravity-piston sediment cores are coarser resolution (ca. every 100 years) and date to ca. 10,000 years cal BP.

Supplement to: O'Beirne, Molly D; Werne, Josef P; Hecky, Robert E; Johnson, Thomas C; Katsev, Sergei; Reavie, Euan D (2017): Anthropogenic climate change has altered primary productivity in Lake Superior. Nature Communications, 8, 15713