Eleventh Year Annual Report: Carbon Science
The Science Group uses both observational data and models to improve understanding of carbon sinks and predict the impact of climate change on the carbon cycle.
The PI's of the Science Group are Michael Bender, Lars Hedin, David Medvigy, Francois Morel, Stephen Pacala, and Jorge Sarmiento.
Monitoring Natural Carbon Sinks
- Additional evidence has been found documenting an abrupt shift in the terrestrial carbon cycle in the late 1980's.
- New forest models predict that nitrogen-limited forests will become sinks under CO2 fertilization, implying that the CO2 fertilization sink should continue.
- A new project is using observations and models to assess the susceptibility of the Amazon rainforest to climate change.
- Quantification of land sinks in the Princeton Earth System Model indicates that annual carbon storage is roughly equally distributed between managed and unmanaged lands.
Improved Tools for Measuring the Ocean Carbon Sink
- A new instrument for making continuous measurements of the dissolved inorganic carbon concentration of ocean surface waters on oceanographic ships has been constructed and tested, and will be regularly deployed beginning in the summer of 2012.
- A new method has been developed for optimally estimating the historical partial pressure of carbon dioxide at the sea surface (pCO2) and has been used to quantify the air-sea CO2 flux since the 1980's.
New Model Capabilities
- A new model has been developed for simulating ocean food web dynamics and is being used to investigate population shifts in the Eastern Subarctic Pacific.
- A model of heterotrophic bacterial activity and its impact on deep ocean carbon sequestration has been developed for use in ecosytem models.
- The impacts of land use on fires have been incorporated into the Princeton Earth System Model.
- Physiological experiments are providing a basis to predict the effects of ocean acidification on phytoplankton growth and production.
- A new model suggests that changes in species distribution and maximum catch potential in the Northeast Atlantic may be strongly affected by predicted changes in the ocean's oxygen content, acidity, and phytoplankton community structure.
- New simulations predict impacts on fish gill function with changes in ocean temperature, O2, and CO2.
Causes of Climate Variability
- Studies of unusual glaciological deposits in Antarctica have yielded ice that is much older than that from deep ice cores, and it may be possible to use such deposits to extend the atmospheric CO2 record 500,000 years or more back in time.
- A new study shows that explosive volcanic eruptions can influence atmospheric CO2 for decades and contribute to carbon sink variations in the ocean and on land.