ORACLE – At the foot of Mount Lemmon, down a short, winding road off State Route 77, a tropical rainforest stands inside Biosphere 2, the University of Arizona’s 3-acre environmental laboratory in the Sonoran Desert.
Joost van Haren gets excited when talking about methane emissions and how they feed climate change. An assistant professor at UArizona, he’s the co-principal investigator for a project in the Biosphere 2 rainforest designed to determine how much methane is emitted by seasonally flooded areas of the Amazon. Researchers hope to better explain what’s known as the “methane flux,” the difference between emissions from all sources and how much of the gas is absorbed by oceans, the soil and the atmosphere.
“People have pointed to the flooded forests of the Amazon Basin as being the (methane) source you can’t see,” van Haren said. “But we do not know that for certain, and so this project sets out to figure that out.”
The project, according to its proposal, aims to establish the first-ever “whole-ecosystem measurements of methane emissions” in a seasonal floodplain forest of the Amazon to understand the mismatch between bottom-up and top-down methane estimates and better grasp the seasonal dynamics and other factors that affect emissions in areas that are both terrestrial and aquatic. For the project, van Haren and his team have designed specialized equipment, which they’re testing in Arizona.
This animation depicts bottom-up measurements of methane emissions in the Amazon rainforest. According to the National Renewable Energy Laboratory, bottom-up estimates are made from on-site measurements by multiple devices.
This animation depicts top-down measurements of methane emissions in the Amazon rainforest. Top-down estimates can be performed on a wider scale. They are measured by aircraft and satellites, University of Arizona researcher Joost van Haren said.
Van Haren said the collected data will be a starting point to understand these mismatches and poorly understood pieces of methane emissions across the globe.
“There’s that mismatch between the measurements,” van Haren said. “But there is also still in the global budget an issue: that we don’t understand what causes the annual variability in the methane flux.”
Two devices are set to be tested in Biosphere 2’s controlled environment before they’re sent to Brazil to take measurements, van Haren said.
The pyramid-shaped building at Biosphere 2 holds the indoor rainforest, where Joost van Haren and his team of student engineers from UArizona are testing their methane-measuring devices. (Photo illustration, based on rendering courtesy of University of Arizona Biosphere 2, and photo by Hope O’Brien/Cronkite News)
(Rendering courtesy of University of Arizona Biosphere 2 and photo illustration by Hope O’Brien/Cronkite News)
The pyramid-shaped building at Biosphere 2 holds the indoor rainforest, where Joost van Haren and his team of student engineers from UArizona are testing their methane-measuring devices. (Photo by Hope O’Brien/Cronkite News)
Researchers and workers at Biosphere 2 enter different levels of the indoor rainforest through small doors. Each level is connected by a spiral staircase. (Photo by Hope O’Brien/Cronkite News)
An extension cord runs from the main concrete building in Biosphere 2’s rainforest down a one-lane walkway to power the equipment Joost van Haren and his team use to install the measuring devices. (Photo by Hope O’Brien/Cronkite News)
This device, built by five University of Arizona senior engineering students and tested in Biosphere 2’s rainforest, will be sent to the Amazon to measure methane fluxes from a tree trunk. (Photo by Hope O’Brien/Cronkite News)
Jacob Longo tests the placement of the tree flux assembly at the base of a Burmese rosewood tree in the Biosphere 2’s indoor rainforest. (Photo by Hope O’Brien/Cronkite News)
Methane is the second-most-common greenhouse gas, according to the European Environment Agency, and is “more than 25 times as potent as carbon dioxide at trapping heat in the atmosphere,” according to the U.S. Environmental Protection Agency.
The EPA says methane is emitted through natural sources and through human activities. Trees growing in the floodplains of the Amazon emitted more methane than all of the Earth’s oceans combined, a 2017 study published in the journal Nature showed.
Designing the system required innovation, van Haren said, because the automated system needs to be able to take continuous measurements in an area of the forest that can experience up to 5 feet of flooding every wet season, which runs roughly January through June. The devices have to adjust to changing water levels, as even a small amount could destroy them.
Biosphere 2 is unique in that it offers a controlled environment where the new equipment can be tested before it is shipped to Brazil.
“We don’t want to test things out in Brazil because fixing it is a much more difficult problem,” van Haren said.
Once the systems are deemed fit, they’ll be installed at selected sites in Brazil.
Joost van Haren, co-principal investigator for a project in the Biosphere 2 rainforest, and his team of student engineers install the mechanisms designed determine how much methane is emitted by seasonally flooded areas of the Amazon in Biosphere 2. (Photo by Alex Gould and Hope O’Brien/Cronkite News, Interactive by Anna Campbell/Cronkite News)
Joost van Haren, co-principal investigator for a project in the Biosphere 2 rainforest, and his team of student engineers install the mechanisms designed determine how much methane is emitted by seasonally flooded areas of the Amazon in Biosphere 2. (Photo by Alex Gould and Hope O’Brien/Cronkite News, Interactive by Anna Campbell/Cronkite News)
Five undergrad seniors at UArizona representing three branches of engineering designed the measuring devices as their final capstone project.
Matthew Northfelt, who’s studying biosystems engineering, was the shop expert, according to fellow team members. His knowledge of the tools in the UArizona’s biosystem engineering shop helped assemble the tree flux and soil/water flux devices.
Jacob Longo, Kyle LeClaire and Brandon Gavel, who are studying mechanical engineering, were in charge of the design and construction of the frames and systems installed in Biosphere 2.
Connor Benson, who’s studying computer engineering, was in charge of coding and preparing the main controller of the system, which saves all the measurements to a computer and controls the motorized equipment.
Hope O’Brien expects to graduate in May 2022 with a master’s degree in mass communication. O’Brien, who has written for the Downtown Devil and interned with Destination I Do, is working for the Phoenix news bureau.
Alex Gould expects to graduate in May 2023 with a bachelor’s degree in journalism and a minor in psychology. Gould, who is a photo intern with The Arizona Republic and a photo editor at The State Press, is working for the Phoenix news bureau.
Anna Campbell expects to graduate in May 2023 with bachelor’s degrees in English and journalism and mass communication. Campbell, who was a senior reporter at The State Press, is working for the Phoenix news bureau.