She went straight to the glove box. Time for a good look at this critter.
On Earth, she’d had many discussions with other biologists about how best to proceed with an unknown sample. All agreed: before slicing, dicing, or extracting, spend some time observing. Get all the clues possible from the living organism.
She plopped the sample from the underground pool under the dissecting scope. That would give her a good overview of the sample, live and in 3-D. She’d collected some of the water with the swimming forms—Marc’s “shrimp”—and a piece of the closest mat.
Under the scope they didn’t look much like shrimp. They were small, pale red, motile forms, moving through the water with beating, whiplike projections. Under good magnification, they looked even less like shrimp, and more like motile colonies. They seemed to be made of several distinct types of cells held together by a flexible matrix. At one end was a knobby protuberance—she didn’t want to call it a head—with a lighter spot.
When she first turned on the light, they were moving very sluggishly, and there were just a few. Again, they clustered under the spot of light in the dish. After a few minutes, they became more energetic. More started to appear.
But from where? She scanned over the rapidly thickening group. Moving the spot of light sent them into frenzied movement until they had relocated the light.
She caught the edge of the mat in her field of view. That was the source. They were swarming from—under? inside?—the mat.
She increased the magnification, focused on a thinner patch. There. She watched, fascinated, as a round, pale red blob embedded in the slimy matrix of the mat began to move under the light, popped out, and swam off. She moved the focus to another one and triggered the built-in vid.
“Hey, Marc,” she called, “come look at this! Your shrimp are popping out of the mat.”
Marc had been working on one of the long trays they used for growing crops. He’d come to relish gardening during the long months of the mission, often volunteering to help Julia in the greenhouse. She could imagine him pottering away in a garden in his later years.
As he approached she got up and gave him her seat. She straightened up, feeling chilled and stiff. The greenhouse was warm enough for just the skinsuit when she was moving around, tending the plants. She set the floor heater to a higher setting. Working in outerwear would be too cumbersome here. She rubbed her thighs for warmth. Even her boot heaters couldn’t fight off the chill seeping from the floor. Darn this cold planet!
Marc watched a while in silence.
“Wow. What are they doing?”
“I’m not sure. Something I did triggered it, though. The light, maybe.”
“I mean, what’s the use of swimming to a wall-hugging life-form?”
“Good question. Same goes for photoreceptors—they’re of minimal use underground.”
“So…” He frowned. “The shrimp evolved on the surface of the planet?”
“Sure seems that way. During Mars’ warm, wet past. These are fossil features.”
“Man, that was a long time ago.” He looked up, frowning. “On Earth, cave creatures are blind. How come these primitive eyes lasted hundreds of millions of years underground?”
“There must be positive natural selection for a swimming, ‘seeing’ form, or else mutations would destroy the genes coding for these features.” She paused, thinking furiously. “So either they need eyes to get around in the mat glow, or there have been several warm, wet periods, maybe lots of them…or the mutation rate is drastically lower here.”
“Hmm. Well, that could be, y’know. Underground, there are no cosmic rays, and Mars has fewer radioactive elements than Earth anyway.”
She raised her eyebrows. “Oh?”
“Yeah, there’re more heavy elements the closer a planet is to the sun. Also, the heavier elements on Mars are concentrated in its core. No tectonic recycling up to the surface as on Earth.”
“I never thought about that. Cosmic rays and radioactive decay account for a lot of the background mutation rate on Earth, so on Mars—”
“It’s probably a lot lower,” he finished.
“Damn. Too many choices. Wish I could talk to Chen about this. I just hate this secrecy.”
He stood up. “Yeah, there’re lots of things I’d like to ask Airbus too.”
“Such as?”
“Such as if they want to use this facility, for example. I’m harvesting beans today, but I could also be planting some for them. I mean, they’d be no good to us, ’cause they don’t mature for two months or more, when we’re long gone.”
“Unless—” She stopped.
“Unless we’re stuck here?”
“It crossed my mind.”
“Well, uncross it. We’ve got to get off this rusty ball of slag,” he growled.
She was surprised at his vehemence. Time to deftly change the subject.
“I’m still thinking about how small their ship is. It’s definitely ERV-sized.”
“Smaller. NASA intended the ERV for a crew of six. That nuke is sized for four, max.”
“Exactly. How are they going to live in something that size and actually do something? I mean, you can survive in something the size of a New York studio during transit, because there’s nothing to do, really.”
He shrugged. “Maybe they plan to use the hab after we’re gone.”
“Hmm. I never thought of that. Wouldn’t they have to ask the Consortium? And tell us? So we can leave it up and running for them? And they’re not very close—for moving in, that is.”
“They can just reposition. The nuke is much better for that sort of maneuvering, I’ll bet.”
