What is the impact of nutrient limitation on the terrestrial carbon sink?

The role that nutrient limitation plays in constraining biomass is a major source of uncertainty in projections of the terrestrial carbon sink, and therefore our understanding of future climate change. An ecosystem level approach, incorporating above and below ground biomass in addition to soil carbon stocks, is vital to understanding the net impact of nutrient limitation across various carbon pools.

Almost all terrestrial ecosystems experience nutrient limitation by nitrogen, phosphorus, or both. To attempt to alleviate nutrient limitations, plants can increase their fine root biomass, stimulate the liberation of nutrients from soil organic matter through mycorrhizal fungi or bacteria, increase the fixation of atmospheric nitrogen to plant-available forms, increase the production of relevant enzymes, and decrease the concentration of nutrients in their tissues. These responses to nutrient limitation vary by plant functional type and can impact plant biomass, microbial biomass, and soil carbon differently.

Our objective is to understand the impacts that nutrient limitation alleviation strategies have on terrestrial carbon stocks. By understanding the costs and benefits that would make certain strategies more advantageous to others in different ecological conditions, we hope to explain seemingly contradictory responses to elevated carbon dioxide experiments. Ultimately, we aim to provide a better understanding of how, where, and why nutrients may limit the terrestrial carbon sink.

Please reach out to tcambron@mit.edu if you are interested in discussing this topic or potential collaborations.