Main image for PaleoPNL: Testing the Progressive Nitrogen Limitaton Hypothesis

Global sites used to test the PNL Hypothesis

While the potential threats of anthropogenic climate change to ecosystems are widely studied, there has been little consideration of the direct impacts of increasing atmospheric CO2 concentrations on essential ecosystem functions such as nutrient cycling.

The Progressive Nitrogen Limitation (PNL) hypothesis posits that as atmospheric CO2 concentrations increase, plants will become increasing nitrogen-limited; this will have strongly negative impacts on primary productivity of ecosystems worldwide.

The aim of this project is to test the PNL hypothesis by collecting and analysing palaeoecological records of terrestrial nitrogen dynamics from periods of increasing CO2 concentrations taken from sites across the globe. This work is part of a collaboration with Kendra McLauchland, Joseph J. Williams and Joseph M. Craine of Kansas State University.

Relevant paper: McLauchlan, K. K., Williams, J. J., Craine, J. M. & Jeffers, E. S. (2013) Changes in global nitrogen cycling during the Holocene epoch. Nature, 495, 352-355.