As the sun rises around the world, hundreds of trillions of leaves open their pores to start a daily cycle. Every leaf is filled with these pores, called stomata, more than a million per leaf. Each second, each stomate allows several billion molecules of water to escape and carbon dioxide to enter. These ingredients allow an elaborate recipe, photosynthesis, to store the sun’s energy in the form of carbon. This process is what I call the breath of the biosphere.
Each year, all the plants on land take up more than a 100 billion tons of carbon. After accounting for respiration and decomposition, land ecosystems on net offset a quarter of our fossil fuel emissions.
About the scholar
Ankur Desai is a professor in the Department of Atmospheric and Oceanic Sciences. His lab investigates how regional spatial pattern, scale, and human modification of land-atmosphere exchanges of heat, water, and carbon influence the lower atmosphere. Lab members also examine how those meteorological and climatic responses affect terrestrial ecosystems.
DISCOVER MORE:
go.wisc.edu/adesai
go.wisc.edu/desailab
Plants lighten the burden for future emissions reductions needed to prevent the worst effects of a warming planet.
Can we keep counting on plants for that service?
In the Ecometeorology Lab at the Department of Atmospheric and Oceanic Sciences, students and scientists are monitoring that breath to answer this question. We build towers in forests, wetlands, lakes and farms across Wisconsin and Michigan.
These towers range from six feet to 1,400 feet tall, and loom over the plants and soil being monitored.
Sensors on these towers measure gusts of winds and the amount of carbon dioxide and water vapor in the air 10 times a second. Using the laws of turbulent fluid dynamics, we can turn those observations into information about rates of carbon uptake and water loss by plants.
We want to understand how this breath changes from one hour to the next, from one season to the next, from one year to the next.
What happens in a hot summer, a wet spring or during an extended cloudy spell? How quickly does the breath restore after an insect outbreak, an ice storm, or a severe drought? Do stomata open less as carbon dioxide in the air increases from fossil fuel emissions? How much do older forests breath compare to younger forests?
This is what we seek to understand in our lab.
For example, to detect subtle shifts in the breath, researcher Jonathan Thom monitors and calibrates sensors collecting real-time, open-access data every day, expertly climbing the towers to maintain them.
Graduate student Jess Turner is using these data to learn how peatlands carbon sequestration changes with their size and how windy they are. Another graduate student, Bailey Murphy, is calibrating complex computer simulations of forests with the towers to understand how forest age and management influence carbon uptake.
Undergraduate researcher James Mineau is using a floating tower in a lake to explain unique seasonal patterns. Meanwhile, postdoctoral researcher Susi Wiesner is tracing all sources of carbon dioxide and methane on a dairy farm in a quest to see how the dairy industry could become carbon neutral.
Our work is done with federal partners such as the Forest Service and the Departments of Agriculture and Energy and alongside state groups such as the Department of Natural Resources, the Wisconsin Educational Communications Board and the Wisconsin Potato and Vegetable Growers Association.
Each seeks its own understanding of the biosphere. Ecometeorology researchers and partners learn one breath at a time.
This essay originally appeared in the Wisconsin State Journal’s Fueling Discovery section on May 4, 2020. Fueling Discovery is a special partnership between the Wisconsin State Journal and the College of Letters & Science.