The University of Arizona hopes that the three massive hill slopes it is building inside Biosphere 2 will attract researchers — and their grant money — to the site.

You can see the slopes being built on the Biosphere webcams.

I wrote about the LEO project when I visited in October. Here is that story:

The University of Arizona is assembling steel frames for three massive hill slopes inside Biosphere 2 near Oracle - a process scientists say is akin to building three giant ships in a bottle.

The steel parts of the $7 million Landscape Evolution Observatory (LEO), and the trucks that carry them, must squeeze through a 10-by-15-foot opening in the steel-and-glass terrarium that was originally built as an experiment in sustaining life in a sealed-off environment.

When assembled, each frame, measuring 40 feet by 100 feet, will be filled with about 3 feet of soil and weigh about 2. 2 million pounds.

It is the first large-scale instrument being built at the Biosphere since the UA took over its operation in 2007. It assumed ownership of the 40-acre property in June.

"I'm so excited about this project," Biosphere 2 Director Travis Huxman said by email from Mexico.

"This will be the only place in the world where we can measure the complete hydrologic cycle."

Each slope will be imbedded with more than 2,000 sensors and samplers that will allow scientists to measure what happens when water flows over landscapes. Weight sensors embedded in the steel frame will allow them to precisely account for the water in the soil.

Scientists will be able to vary the temperature and the regularity and intensity of precipitation. Eventually, they will add and subtract vegetative cover to assess the role of plants on runoff and soil chemistry.

Planning for the experiment involved scientists from seven UA departments or disciplines - soil, water and environmental science; ecology and evolutionary biology; geosciences; hydrology; water resources; atmospheric sciences; and natural resources.

The UA hopes to attract an array of scientists - and research grants - to its new scientific instrument, which Stephen DeLong, lead scientist for the project, compared to building an astronomical observatory or a particle accelerator.

It will allow earth scientists to conduct experiments on a large scale without losing the precision of a laboratory.

"It's a whole new thing for the earth science community," said DeLong.

Initial experiments will be performed without vegetation, he said.

Hydrologists and geologists want to observe the patterns and mechanics of water moving through the rock, DeLong said.

Scientists are also interested in learning how the volcanic rock they selected and ground to a homogenous size will weather over time.

The volcanic rock, from the Flagstaff area, was selected for its chemical nature. "It's full of volcanic glass, and the minerals in it are all susceptible to chemical weathering," DeLong said. Olivine, for example, will become clay.

When plants are added, they will probably be desert varieties that survive in unenriched soil, and the climate will be kept fairly warm.

DeLong doesn't rule out colder climates in the future. Biosphere 2 has the ability, he said, to make it cool enough to observe effects of snowmelt.

DeLong said the observatory will be able to answer important questions about how watersheds work, and how continued drought and higher temperatures will affect them in the future.

It is being built in the half-acre site where food was grown for the participants in the Biosphere's human experiments. It was called the "intensive agriculture biome."

Initial experiments and the cost of building the observatory are funded from a pot of money given by the Philecology Foundation, the charity founded by Texas billionaire Ed Bass, who bankrolled the original construction of Biosphere 2.

Parsons Steel Erectors of Tucson fabricated, and is installing, the steel. Lloyd Construction and M3 Engineering are in charge of building and engineering.