UA News

Biosphere 2 is in the process of building three hillslopes to be part of a new experiment to test and better understand how water, soil and vegetation interact.

The ability to accelerate the evolution of landscapes to evaluate ways that vegetation, climate, water runoff and numerous other variables affect the soil and predict reactions in ecosystems would be a tremendous boon to science.

And that is what researchers at The University of Arizona's Biosphere 2 are attempting.

The largest experiment to be conducted at Biosphere 2 since the UA took over management of the site has moved out of its 2-year planning stage and into its construction phase.

"It's exciting to see things beginning to take shape," said John Adams, assistant director of planning and facilities at Biosphere 2.

Crews have begun moving 4,000 tons of soil in what was once a farm greenhouse – formerly called the intensive agriculture biome – for the Biospherians who lived and conducted research during the 1990s at the site, located north of Tucson in Oracle.

The dirt removal and demolition also involves removing nearly 20,000 square-feet of concrete block walls and other structures, which should be completed in about four weeks.

The space will be converted to include three identical enclosed landscape units, or artificial hillslopes, for what UA researchers at the Biosphere expect to be a 10-year-long experiment – which will cull the expertise of scientists in the areas of hydrology, geomorphology, ecology, biology, biochemistry, genomics and soil, water and environmental sciences.

"We know that certain aspects of our climate are changing," Adams said, adding that the scientists want to be able to better predict that change, particularly related to water and water resources.

Among the overarching questions are in what ways do ecology, geomorphology, biochemistry and other influences affect the way water moves across complex landscapes? Also, how exactly does precipitation result in evaporation, infiltration, runoff, transpiration and other forms of flow?

"This is something that has not been done very well," said Javier Espeleta, Biosphere 2 associate director of science and one of the principal investigators on the project.

The next step will be to design and install below-ground instruments for the hillslopes that would serve to sample the soils, measure the moisture in the soil and other physical and chemical aspects responses to material and evaluate plant growth and the exchange of energy and gas, among other things.

Already, scientists are searching for the ideal soil and have identified a basaltic rock as a potential substrate

"It must be pure and cannot have gone through weathering because we want to record that weathering," Espeleta said. "We must condense thousands and millions of years of processes into one decade."

Espeleta said a series of workshops were held with UA scientists, the Hydrological Synthesis Center at the University of Illinois at Urbana-Champaign and their colleagues to determine the best design for the "massive interdisciplinary experiment," which will merge laboratory and field studies into one project.

Creation of the hillslopes is expected to be complete in one year – and then the science will begin. Over time, scientists will begin to introduce vegetation and manipulate the climate within each of the three enclosed areas.

"We don't want to mimic the outside world," Espeleta said. "We want to create a study model that we can control. The more we can control, the more geared we are to better understand the mechanisms, thereby increasing our ability to extrapolate across environments."