In mid-May, a small research tower was installed in Curtis Prairie. A flux tower – or eddy covariance tower – holds scientific instruments that measure fluctuating amounts of carbon dioxide and other greenhouse gases in the air. The tower is part of a pilot research project to better understand the role prairies play in cycling and sequestering carbon dioxide.

What is the small tower in Curtis Prairie?

A flux tower – or an eddy covariance tower – measures fluctuations of carbon dioxide, water vapor, and other gases in the atmosphere.

As air flows across the landscape, it swirls (or eddies) and moves gases, water vapor, and heat between the atmosphere and the Earth. When air moves upward, it carries carbon dioxide emitted by plants and the soil. As air swirls downward, it brings carbon dioxide that can be absorbed by plants through photosynthesis and stored in vegetation and the soil.

Sensors on the tower capture data about these air currents and the gas exchange between land and atmosphere. They also measure local microclimates (small areas of variable climate conditions) that affect how ecosystems exchange gases. In other words, flux towers measure how the earth “breathes.”

What does a flux tower do?

A flux tower is equipped with sensors that collect real-time data about the fluctuation amount of carbon dioxide and other greenhouse gases, like water vapor, in the air.

The exchange of carbon dioxide between ecosystems and the atmosphere varies across relatively small areas. That exchange may be influenced by different plant communities (such as prairies or woodlands), landscape types (such as natural, urban, or agricultural areas), and the time of day or the seasons.

Prairies are highly efficient at storing carbon underground and through photosynthesis. Real-time measurements of gas exchange can tell us more about the role of prairie ecosystems in storing carbon.

Why put a flux tower at the Arboretum?

Arboretum and Wisconsin researchers are collaborating to study carbon exchange and sequestration in prairies, and to learn if there are variations across remnant or restored prairies, younger or more established prairies, or as a result (or lack) of prescribed fire.

The Arboretum is in a unique position to host a flux tower. It is the home of early prairie restoration experiments and of Curtis Prairie, one of the oldest active and ongoing prairie restorations in the world. This provides an opportunity to collect and analyze valuable data about the role of native ecosystems in carbon cycling. Southern Wisconsin is also home to restorations and remnants of different sizes, types, and ages, which could be valuable sources for gathering comparative data.

There are hundreds of flux towers around the world. The Arboretum tower can add an important data point to global analyses of how the Earth functions and how we manage and restore it.

As a university research center and a popular visitor destination, the Arboretum also offers countless opportunities to engage the public and scientific collaborators in research. Arboretum research ecologist Jared Beck says, “my hope is that hosting a flux tower not only generates data but also stimulates a conversation about ecological restoration and how restoration of native ecosystems has potential to address global environmental challenges like climate change.”

Who are the project partners?

The flux tower in Curtis Prairie is currently part of a one-year pilot project partnership between the UW–Madison Arboretum, UW–Madison researchers Paul Stoy and Ankur Desai, and Applied Ecological Institute.

Jared Beck is the UW–Madison Arboretum research ecologist and leads the research program.

Paul Stoy is a professor in the Department of Biological Systems Engineering. Visit Professor Stoy’s webpage.

Ankur Desai is the Vilas Distinguished Achievement Professor and department chair in the Department of Atmospheric and Oceanic Sciences. Visit Professor Desai’s Ecometeorology Lab website.

Patrick Bohlen is the UW–Madison Arboretum director.

Applied Ecological Institute focuses on the science and application of ecological solutions in restoring healthy ecosystems.