A 700,000-gallon replica of the Sea of Cortez in the Arizona desert


The coral reef that once lived in the 700,000-gallon tank of ocean water in the Arizona desert, hauled in from Belize after breaking off in a storm in the late 1980s, is now pretty much dead. It met the same fate as another Biosphere 2 experiment, which involved eight men and women living off their own crops inside a 3.1-acre glass sphere for 24 months in 1993: It was good while it lasted and was just a blip in the ever-evolving science wonderland that is Biosphere 2.

To replace the defunct coral sanctuary, scientists at the University-of-Arizona-owned research facility are madly drafting designs for a new desert ocean, this time to emulate the Sea of Cortez. Instead of pumping heat into the tank to keep its temperature in the mid-to-high 70-degree range for tropical reef, they’ll allow the new sea to fluctuate in temperature to replicate something more like the gulf. Cortez wildlife such as sea stars, small sharks and possibly sea turtles will populate the 6,000-square-foot tank (that’s a bit larger than two Olympic swimming pools).

An early sketch, by Dr. Raphael Sagarin, of the new ocean at Biosphere 2.
Dr. Raphael Sagarin, who is heading the new ocean project at Biosphere 2. Photograph by Paul Ingram.
A wider view of the research facility Biosphere 2, which is 35 miles north of Tucson.

So why build a living, breathing, semi-tidal, salty, cool ocean in the bone-dry desert? It makes perfect sense, says marine ecologist Raphael Sagarin, who’s leading the project. The Sonoran desert and Gulf of California share an intimate symbiotic relationship. Every July and August, southern Arizona and southwestern New Mexico experience much-needed monsoons that provide nearly half of the region’s annual precipitation. That moist deposit, airlifted yearly from the Sea of Cortez and sucked several hundred miles north to summer low-pressure systems, makes the thriving desert ecosystem possible.

“These desert plants are really adapted to the large pulse of rain,” says Sagarin, who grew up on Cape Cod in Massachusetts and hoofed it to the West Coast at his first chance, where he says the marine biology was much more fascinating. “It’s the crux of why the Sonoran desert has such rich plant and animal life.”

Seeing this direct connection between the ecosystems in the Gulf of California and the Tucson desert motivates Tucsonans to learn about conservation challenges facing the gulf, Sagarin says. A problem for the ocean is a problem for the desert. That’s the point of the new desert sea – to research and problem-solve issues like coastal pollution, climate change, over-fishing and new zoonotic diseases.

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