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Studying carbon cycling in one of the driest places on Earth

Researchers at Arizona State University (ASU) have turned their attention to one of the driest regions on the planet to study the complex dynamics of carbon cycling. The team conducted field work in the Namib Desert, which stretches more than 1,200 miles along the Atlantic coast, to investigate what controls the release of carbon dioxide from soils.

The study ultimately revealed that subtle differences in surface topography and erosion have a strong influence on the behavior of microorganisms in the soil, which affects carbon cycling. Even in the driest places, there were signs of life influencing carbon cycling.

Study lead author Heather Throop is an associate professor in the ASU School of Earth and Space Exploration and the School of Life Sciences.

“The amount of carbon dioxide in the atmosphere affects our climate, so understanding what affects the release of carbon from soils is important for predicting how climate will change in the future.” said Professor Throop.

The research was focused on six separate sites in the desert that varied in annual precipitation. At each site, the team worked continuously day and night for 48 hours to collect data. The scientists analyzed the landscape structure and the local plants to select the best representative areas to sample. 

Next, the researchers simulated rainfall and used gas analyzers to measure carbon dioxide release from soils. This allowed the experts to gain a better idea of how carbon cycling responded as soils dried after the simulated rain.

“It’s really an incredible amount of data to collect manually,” said Professor Throop. “And having a crew of dedicated and enthusiastic students made this work possible. Often for remote field work like this we just get a snapshot of what is happening at one or two sites or at a few points in time. It was exciting to be able to collect the data continuously for a few days and at six different sites.”

The ASU team collaborated with students from the University of Namibia and the Namibia University of Science and Technology. Study co-author Vimbai Marufu is a graduate student at the Namibia University of Science and Technology.

“The ability of technology to record soil carbon was outstanding,” said Marufu. “What I treasure the most from the experience is what it means to work on an interdisciplinary team and the unexplainable satisfaction of being close to nature.”

With a recent grant from the National Science Foundation to ASU, students from the United States will continue to conduct research in the desert with Namibian researchers. 

“We hope to use this work to help us in understanding how deserts respond to a changing climate,” said Professor Throop. “How biological processes function in the extreme dry of the Namib Desert will gives us clues about how relatively wet deserts will behave under drier conditions.”

The study is published in the journal Planet and Soil.

By Chrissy Sexton, Staff Writer

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