“It seems to fit what we’re doing.”
“Down the rabbit hole we go, then.”
She gazed down and saw at the very limit of the weak lamplight bigger things. Much bigger. Gray sheets, angular spires, corkscrew formations of pale white that stuck out into the upwelling gases and captured the richness. One spindly, fleshy growth looked like the fingers of a drowned corpse, drifting lazily in the currents…
She shook her head to clear it. Stay steady, here.
Below the level of the pool ledge twisty side channels worked off at odd angles. These ran more nearly horizontal, and they explored them hurriedly, clumping along until the ceiling got too low. No time to waste crawling back into dead ends, she figured. They headed back to the main channel and then found a broad passage that angled down. It was slick and they had to watch their footing.
The mats here were like curtains, hanging out into the steady stream of vapor from the main shaft of the vent. Some seemed hinged to spread before the billowing vapor gale. She was busy taking samples and had only moments to study the strange, slow sway of these thin membranes, flapping like slow-motion flags.
“Must be maximizing their surface area exposed to the nutrient fog,” she guessed.
“Eerie,” Marc said. “And look how wide they get.”
“There’s sure as hell a lot of biomass here.”
“Wonder if any of it’s edible.”
“Hungry, huh?” They both laughed, a bit tensely.
At turns in the channel the mats were the size of a man. She took a lot of shots with her microcam, hoping they would come out reasonably well in their lamp beams. Gray and translucent, under direct handbeam she could see her hand through one.
These forms owed their origin to the warm, moist eras of the Martian antiquity.
The mats—and what else?—lived in such labyrinths as this, all around the globe? They could harvest the moisture billowing from heat below, and perhaps melt the permafrost nearby. At the edges of Earth’s glaciers lived plants that actually melted ice with their own slow chemistry.
The thermal vents and their side caverns could be extensive. With an exposed surface area as big as Earth’s, there was plenty of room for evolution to experiment.
Marc whispered, “Nothing like this pale ivory cavern on Earth. For sure.”
Ruled as it was by boisterous, efficient aerobic life. Anaerobes had long ago retreated to inhospitable niches like hot springs and coal mines. In that infertile ground they survived, but remained as microbes, spawning no new forms. On Mars, oxygen-loving forms never evolved. The atmosphere escaped too soon.
Julia gently caressed a mat as it lazily floated on the vapor breeze. Plants, flourishing in the near vacuum. She could never have envisioned these…
She dropped down a few more meters, blinking. How much was she seeing and how much was just illusion?—the product of poor seeing conditions, a smudged helmet view, her strained eyes—
“Hey. Time.”
She felt her fatigue as a slow, gathering ache in her legs and arms. Experience made her think very carefully, being sure she was wringing everything from these minutes that she could. “How far down are we?”
Marc had been keeping track of the markings on the cable. “Just about one klick.”
“What’s the temperature?”
“Nearly ten. Almost toasty. No wonder I’m not feeling the cold.”
“This vent could go down kilometers before it gets steam-hot. And we’ve just reached the cavern level.”
“Julia…”
“I know. We can’t go farther.”
“It’ll be a long, tough climb out. Soon be dusk up there.”
Be getting deathly cold on the surface, and fast, yes.
She was on a small ledge, about five meters below Marc. A strange longing filled her.
“I know. I’m not pushing for more, don’t worry. Biologists need oxygen, too.”
Automatically she started to cut a small sample out of the closest mat, a thick hanging curtain suspended just within reach. It was surprisingly tough, like thick kelp. She found she was puffing with the exertion. Her suit exhaled with a slight hiss. Suddenly the mat whipped around, pinning her against the rock wall. She was in the dark, as if someone had closed a thick curtain in front of her.
Marc responded to her yell. “Jules, where are you? I can’t see you.”
“Here!”
“You’re behind that mat?”
“Yeah.” Breathe deeply, speak clearly. “Must be some kind of reflex reaction. I was trying to take a sample, and this hanging mat slammed against me.”
Training reasserted itself. Marc answered in calm astronautspeak. “What is your position? All I can see is the cable.”
“I’m standing on a small ledge, being held against the wall by a lot of mat stuff. Can’t see anything.”
“Still got your scalpel?”
“Negative. Must’ve dropped it. It wasn’t much good anyway. This stuff is tough.”
