Breathe

Part 5

We strolled down the gravel footpath followed closely by Gina and preceded by Hopey, past the vegetable gardens and fruit trees toward the center of the dome. I followed towing the trolly behind me. Michelle looked around her, indicating it all with a sweep of her arm, "So, this is what produces the oxygen we're breathing."

Jill answered, "Actually, no. Well, it produces some of it, but we have hundreds of trays of oxygen-producing algae in the sterile conditions of our laboratories underground where there's no risk of contamination with rogue algae. That's where most of our oxygen comes from. It's easier to control oxygen levels that way, without having to worry about the rates of decomposition of vegetation, or the amount of fish and birds and other animals. The Habitat's systems can increase or decrease oxygen production fairly quickly and very easily. The amount of oxygen in the air is picked up by detectors and they automatically cause the intensity of the lights illuminating the algal trays to vary as required. Electricity for that, and everything else, is supplied by solar cells all around the perimeter of the Habitat and the nearby electricity store. If we were away for days or weeks the Habitat would continue to automatically maintain the balance."

Michelle touched the leaves of a shrub. "Is that dew?"

I chuckled, "No. The sprinkler system is programmed to water everything during the night."

"Is everything automated?"

"Almost. We still have to plant and weed and reap the fruits and veggies, milk the goats, and collect the eggs."

"Where does the water come from? Do you have a well?"

"There is a backup well, but it hasn't been needed in the more than fifty years since the Habitat was first being built. All water is recycled. Evaporation during the day condenses on the inside of the dome and is caught and channelled into tanks. That's filtered for safety's sake to become our drinking water and is sprayed as rain each night."

We walked around a group of mulberry trees to reveal the large, vertical, flat panel at the center of temperate-1. The bottom of the structure was about a meter above head-height, and it was another four meters taller. It was made of a lightweight flexible plastic, strengthened by ribs radiating from the narrower side to the wider.

Michelle looked at if for a little while. "What's this? It looks like a sculpture of the tailfin of a giant fish."

Jill laughed in surprise, then pursed her lips in thought, "I'd never seen it as being like that, but you're right. I'd always thought of it like a bird's wing, though it really owes more to the handheld paper fans people used to wave in their faces to keep cool on hot days."

I explained, "Back when Biosphere 2 was built in USA, they found that some plants do best if they're exposed to wind. In the early days here, we had a large rotating fan to create a wind, but it had two big drawbacks. It made a lot of noise, and small birds were sometimes killed by the blades. The first thing that was tried was to enclose it in a mesh shroud. That protected the birds but wasted energy and seemed to make the noise worse. So this was developed. It's silent and doesn't hurt anything. The Habitat's computer starts and stops it at random times and the direction it points is also randomly chosen. There's one of these in each environment, except the rainforest -- there's no room there -- and the water environments both have two; one each in the air and in the water."

Michelle said, "You mentioned the laboratories earlier, where the algae are that make the oxygen, that they're underground. Is that like the living quarters?"

Jill said, "A little bit. The living quarters are barely underground, with just a meter or even less earth over them. The ground we're walking on has to be deep to support the trees. In the two temperate environments it is 16 meters deep. In the two savanna environments it's only 8 meters deep. The laboratories are under that."