Isotope Labelling Study Identifies Importance of Rooting Depth in Nitrogen Uptake of Tundra Vegetation

Isotope Labelling Study Identifies Importance of Rooting Depth in Nitrogen Uptake of Tundra Vegetation

September 1st, 2016
-
The Objective: 
  • Quantify access of plants and microbes to increased nitrogen due to thawing permafrost and deepening of active layer.
New Science: 
  • Conducted an15 N tracer experiment for plant species growing on the Barrow Environmental Observatory (BEO).
  • Data combined with a nutrient competition model to test hypotheses regarding access of plants and microbes to nitrogen.
The Impact: 
  • Roots, especially near the permafrost table, were not able to access available nitrogen due to limited root biomass.
  • Nitrogen uptake in other regions of the soil was a function of plant uptake kinetics and competition with microbes.
  • Knowledge derived from this model data exercise provides insights on essential root and microbial traits to include in ALM.

15N tracer applied to soil could be either taken up by microbial decomposers and roots or adsorbed onto mineral surfaces.

Funding: 

This research was supported by the Director, Office of Science, Office of Biological and Environmental Research of the US Department of Energy under Contract No. DE-AC02-05CH11231 as part of the Next-Generation Ecosystem Experiments (NGEE Arctic) project.

Contacts: 

NGEE Arctic