Nutrient effects on internal nitrogen and phosphorus concentrations

In a paper just published online in Oikos, my colleagues and I evaluate the effects of experimental nitrogen and phosphorus additions on internal nitrogen and phosphorus concentrations and show that (1) adding a particular nutrient generally enhances its internal concentration in primary producers and (2) overall, there is no reduction in the concentration of one nutrient associated with addition of the other nutrient. In fact, across the entire dataset, which spanned marine, freshwater, and terrestrial systems, phosphorus additions enhanced internal nitrogen concentrations. This suggests that phosphorus is generally necessary for nitrogen acquisition and highlights a mechanism for N-P colimitation. This work is an extension of a National Center for Ecological Analysis and Synthesis (NCEAS) working group, and the NCEAS press release on our paper is linked here.