Aurora Read Free

kids who might visit.
    Then off again. “Where to now?”
    “Off to the salt mines,” Devi declares, knowing Freya will be pleased; they’ll stop at the dairy near the waste treatment plant, get ice cream.
    “What is it this time?” Freya said. “More salt in the salty caramel?”
    “Yes, more salt in the salty caramel.”
    This is a stop where Devi can get visibly irate. The salt sump, the poison factory, the appendix, the toilet, the dead end, the graveyard, the black pit. Devi has worse names for it she says under her breath, thinking again that no one can hear her. Even the fucking shithole!
    The people there don’t like her either. There is too much salt in the ship. Nothing wants salt except people, and people want more than they should have, but they’re the only ones who can take it without getting sick. So they all have to eat as much salt as they can without overdoing it, but that doesn’t really help, because it’s a really short loop and they excrete it back into the larger system. Devi always wants long loops. Everything needs to loop in long loops, and never stop looping. Never pile up along the way in an appendix, in a poisonous sick disgusting stupid cesspool, in a slough of despond, in a fucking shithole. Devi sometimes fears she herself will sink into a slough of despond. Freya promises to pull her out if she does.
    So they don’t like chlorine, or creatinine, or hippuric acid. The bugs can eat some of these things and turn them into something else. But the bugs are dying now, and no one knows why. And Devi thinks the ship is short on bromine, which she can’t understand.
    And they can’t fix nitrogen. Why does nitrogen break so often? Because it’s hard to fix! Ha-ha. Phosphorus and sulfur are just as bad. They really need their bugs for these. So the bugs have to stay healthy too. Even though they’re not enough. For anyone to be healthy, everyone has to be healthy. Even bugs. No one is happy unless everyone is safe. But nothing is safe. This strikes Freya as a problem.
Anabaena variabilis
is our friend!
    You need machines and you need bugs. Burn things to ash and feed the ash to the bugs. They’re too small to see until there are zillions of them together. Then they look like mold on bread. Which makes sense because mold is one kind of bug. Not one of the good ones; well, bad but good. Bad to eat anyway. Devi doesn’t want her eating moldy bread, yuck! Who would do that?
    You can get two hundred liters of oxygen a week from one liter of suspended algae, if it is lit properly. Just two liters of algae will make enough oxygen for a person. But they have 2,122 people on board. So they have other ways to make oxygen too. There’s evensome of it stored in tanks in the walls of the ship. It’s freezing cold but stays as liquid as water.
    The algae bottles are shaped like their biomes. So they’re like algae in a bottle! This makes Devi laugh her short laugh. All they need is a better recyclostat. The algae always have bugs living with them, eating them as they grow. With people it’s the same, but different. Growing just a gram of
Chlorella
takes in a liter of carbon dioxide and gives out 1.2 liters of oxygen. Good for the
Chlorella
, but the photosynthesis of algae and the respiration of humans are not in balance. They have to feed the algae just right to get it between eight and ten, where people are. Back and forth the gases go, into people, out of people, into plants, out of plants. Eat the plants, poop the plants, fertilize the soil, grow the plants, eat the plants. All of them breathing back and forth into each other’s mouths. Loops looping. Teeter-totters teetering and tottering all in a big row, but they can’t all bottom out on the same side at the same time. Even though they’re invisible!
    The cows in the dairy are the size of dogs, which Devi says is not the way it used to be. They’re engineered cows. They give as much milk as big cows, which were as big as caribou back