You are here
Harvard Forest Symposium Abstract 2015
- Title: New Trends After a Decade of Soil Warming: Can Sustained Warming Lead to Progressive Phosphorous Limitation?
- Primary Author: William Werner (Marine Biological Laboratory)
- Additional Authors: Michael Bernard (Marine Biological Laboratory); Frank Bowles (Research Designs); Jerry Melillo (Marine Biological Laboratory)
- Abstract:
For 12 years and running, we elevated soil temperatures at the Barre Woods Soil Warming experiment to +5ºC above ambient soil temperatures. In the first 10 years of warming (2003-2012), in the heated plot relative to the control plot we consistently measured an increase in nitrogen availability (nitrogen mineralization), an increase in soil respiration, and enhanced carbon sequestration in woody tissue of the trees (increased woody increment). However, in the two most recent years, while we still observed increased in soil respiration and nitrogen mineralization, we are no longer observed increased woody increment.
Nitrogen is generally considered to be the nutrient that limits primary productivity and carbon sequestration in northeastern forests, and our results from the first decade of warming are consistent with this picture. Our working hypothesis is 10 years of warming triggered a shift from nitrogen limitation to multiple element limitation, with phosphorous playing an important role. This could explain the cession of increased woody increment despite the persistence of increased nitrogen mineralization. Some preliminary analysis of N:P ratios in green leaves and leaf litter supports this hypothesis, and future work will include a more thorough investigation of the role of phosphorous in this experiment. - Research Category: Forest-Atmosphere Exchange
Large Experiments and Permanent Plot Studies
Soil Carbon and Nitrogen Dynamics
