The call comes in the evening, though it’s morning on the other side of the world. K. is demanding that I leave my study right this minute to look at the sea. I grab my sample bag and rush outside, too curious to argue. It takes less than a minute for me to jog from my house to the end of the jetty.
I peer down at the surface of the water. I can’t see much; the sun set ten minutes ago.
“What am I looking for?”
“Look at the water. What color is it?”
I fumble in my bag for my good flashlight—one I made myself, with a patented triple lens—and turn its ultra-sharp beam on the ocean.
“Why is it doing that?” I whisper. “Why is it just sitting still?”
“What color is it, D.?”
“Green. The whole thing is just solid green.”
A long, textured sigh issues from my earpiece. “God,” K. hisses. She seems on the verge of tears, but with some effort she controls her breathing.
I can’t wait. “Is this that algae bloom of yours? What the hell is it doing here?”
She inhales purposefully. I hoped she’d have to pull herself together to correct me, and it works; when she speaks again, her voice is steady.
“Not algae. It’s a lichen—or it was when I started studying it. I’ve got no idea what it’s doing there, other than growing. I’m still making sense of it myself. Do you remember my dissertation?”
Of course I remember. A year ago, K. printed out that dissertation and mailed it to me personally, neatly stapled and, I thought, perfumed. I read the abstract a dozen times before I gave in and called. She explained it all to me, in her laughing-brook voice, with a patience I hadn’t been shown since I was a girl.
She had found me in a directory of remote researchers and wrote to ask me to photograph some of the lichens in my little biome, which was, she pointed out meaningfully, on the exact opposite side of the world from where K. herself lived, in New Zealand.
In the dissertation K. had referred to the floating, living islands that popped up along the northwestern coast as “ur-lichens,” or, in more casual contexts, “super-lichens.”
It was the second name that caught on in her small collective of Māori ecologists, the only ones paying attention at first. The super-lichen was a local disaster, overshadowed by the death rattle of the oceanic coral reefs. The collective relied on a growing network of citizen scientists to track the expansion—what they came to call the Bloom—as it spread unchecked along the coastline.
K. had volunteered to make contact with someone who could keep the last watch, as far away from the origin as possible. My island outpost, her own antipode, would mark the finish line for a fully global superbloom, if it ever got that far. I didn’t ask her what good it would do anyone to know how much of the ocean was lost at that point. I don’t think either of us expected that such a thing could actually happen in our lifetimes.
When the Bloom began to move down the northwestern coast of New Zealand, K. packed up her belongings and moved with it. She still called me occasionally to ask for updates from my side of the world. I would take the call on my headset while I worked the glass.
“A fungal spore sends its hyphae into the algae,” she’d say, drawing out the Greek ending—hy-fee—in a grin that I could almost see. Through my headset I could hear her, even while I sanded finished prisms or made coke fuel for the forge. Sometimes she asked me about my work, but I had no talent for translation.
Instead, I sent photos, both of the growing lens and the lichens—no samples, she said, as the risk of contamination was overwhelming. I also sent her tools. Funding was scarce for lichen-watching, but I had all the raw materials at my disposal to replicate and improve every piece of glassware K. needed, and shockproof shipping was free under my contract. When K.’s digital microscope was stolen, I sent her a replacement—a bespoke mechanical version from my own workshop, with a hardwood carrying case, hand-engraved with her initials.
After that, the calls were daily. My ears adapted to the sound of K.’s voice and listened for it even after we hung up. I could not help but absorb her passion, her creeping panic, over the terrible might of the Bloom. Alone of ocean beings, it seemed to delight in the spiking acidity caused by human pollution. The Bloom was so good at growing, so blazingly energy-efficient, especially near the surface, that huge mats of it emerged in shallow waters around dozens of islands in the South Pacific. Where they met the coasts, the floating mats merged, surrounding whole archipelagos in swamps that turned alarmingly toxic.
I asked K. how it reproduced.
“This one doesn’t,” she said. “It only grows.”
This is what I learned in those months of building: a lichen is not an organism, but a community of organisms acting collectively. The photosynthetic members, single algae cells or long strands of sun-loving cyanobacteria, feed the fungus via the hyphae, which penetrate the algae’s cell walls to extract their sugars. In return, the fungus offers a safe habitat for its support organisms. Together, the hyphae and the photosynthetic cells make a single continuous unit of life, self-replicating and infinitely adaptable.
“On its own, the fungus is a clump of hyphae. It can’t form any discernible structures. It dies.”
“So the fungus is a parasite?”
“We’d have to ask the algae.”
We passed good months this way, her calling, me listening. She was my favorite sound.
Then the Superbloom took the rest of the ocean in the course of a single night, twenty years ahead of schedule, and K. called me again.
“When I woke up this morning, I thought my satellite feed was broken—the map was just covered.” It’s hard to process her words.
“…But if it’s reached you already, we’re long past any way of stopping the spread,” she concluded.
I listen to the birdsong through the phone: a kookaburra’s alien laughter. Behind it, the wind is high, as it is here. I can see the first storm of summer growing on the horizon.
The kookaburra falls silent. I wipe my eyes with my forearm.
“Is there anything we can do? Maybe if…?” I trail off, unable to even frame the question.
“You should stock some food,” she says gently. “If I think of something, I’ll… I’ll let you know.”
It’s fully dark now. The vast, pale expanse could almost be the natural ocean, if it weren’t for the disturbing stillness of it beneath the starless sky. I feel panic rise, tightening my lungs and heart.
“Oh, and D.? Are you still there?”
I cough, force my voice deeper. “Yeah.”
“Don’t touch it.”
The Caldera is the perfect place to light a beacon, and I was once the perfect person to keep it lit. My technical training is in photonics, the art of manipulating and redirecting light. I was one of the first to build lenses from gadolinite, the oily black mineral that makes up the base of the Caldera, though I did it in the comfort of my childhood home on the mainland. But I was losing patience with the frantic pace of manufacturing; I was ready for a quieter life.
By then, I had made some friends in government, and one of them shared my name with the Bureau of Scientific Engagement, a collaboration between government scientists and propagandists. Riding a wave of investment in space ventures, the project aimed to thrill the nation by building a self-powering radio beacon that would send an eternal message to alien worlds. Previous communications to the extrasolar expanse had been ephemeral: a five-minute transmission from the North Pole of spoken greetings in two hundred Earth languages; a gold disk embossed with Da Vinci’s naked eight-limbed man and some other things, launched into the sky. The time had come, in the BSE’s opinion, to make ourselves known to the universe on a permanent basis.
A simple transmitter would emit a continuous wavelength: a hundred mHz, just energetic enough to escape the atmosphere. My job would be to build and then maintain a lens out of gadolinite thermal glass, a form of passive solar power. The lens would both concentrate the signal into a narrow beam and power itself virtually forever, storing solar energy in a solid-state battery that fed the same monotone signal, even at night.
I was to build the whole thing on-site, on a colonial outpost with no other lucrative resources to offer, nor remaining residents to exploit. The Caldera is an empty-named place, a safe enough distance from real human civilization that the mainland, at least, would have warning, should the worst occur. What the worst might entail, we did not discuss.
The day after the Superbloom starts the same as usual, and it’s not until I look out the window that I recall what has changed. The Caldera is a narrow island, curled like a fetus against the sea. To my left, the bulk of the island, a great crescent of steaming jungle, pours down into the bay as always. But the basin itself is deathly still, suffocating under the weight of a mat of new life that extends, waveless, to every horizon.
It’s hard to look at.
Above the Bloom, on top of the hills on the opposite end of the crescent island, the black, flat-topped needle of the signal tower is barely visible from here. It’s been three months since I got it running, and two months since I hauled my personal items to the opposite side of the island from the tower, into one of the last remaining buildings on the island. The tower was starting to make my head buzz.
I check the monitor: the signal is fine. A one-note performance, without even the texture of an ending, communicating the bare minimum of reality. The beam moves like an out-of-control spotlight, the focused radio waves sweeping around the planet as it turns, carving out curly ribbons of space in their near-random search for a receptive target. In the early days of the project, there had been some talk of sending out a message with actual content, even a simple greeting. But then one of our physicists showed that if we stuck to one frequency, the signal could easily reach the nearest galaxy cluster and would likely be detectable at twice that distance. The programming team was furious, but intergalactic sounded better than interplanetary in the headlines, so the one-note message won out.
My contract gives me a year of watch after I finish construction, but already it is impossible to picture life on the mainland. No word has arrived from my supervisors, but that doesn’t surprise me. Will I last nine more months here, without supplies, without a plan? I do not dwell on this.
That night, I make my first discovery.
“The Bloom emits light.” My words echo on the other end. Does my voice sound different to her because she’s listening to its inverted form—across the world, upside down, in broad daylight?
“I thought I was seeing things,” she whispers after a moment.
“I see it, too. It’s clearer at night, but even in the light it’s pulsing. Why?”
“I don’t know.” Her voice is hushed, hurried, as though someone might be listening. “It wasn’t doing this even a week ago, but this Bloom changes so fast. If it were to somehow recruit some new microorganism, something that glows…”
“A third colony member?”
“It’s possible. We wouldn’t know. But there are hundreds of bioluminescent species.”
“Why do they glow?”
“Camouflage. Prey attraction. Signaling to the predators that eat their predators.”
“Would that look like… a pulse? Rhythmic?”
“No. It’s purely responsive.”
“Doesn’t the pulse remind you of a heartbeat?”
“Yes, of course.”
In the green expanse of the bay, a field of little leaflets drinks in the dimmed sun. On the far side, straight across the bay, the black crown of the signal tower looms like a purposeless alien.
“Does the Bloom, or some part of it, have a heartbeat?”
Later, a call from the department: deliveries will be suspended for the time being, given the circumstances. I do not have to ask what the circumstances are. All around the world, I imagine, human beings are attempting to negotiate with the invader, touching and hacking and plowing, growing more desperate for a response. But the Bloom will not hear them, any more than I would hear a threat spelled out in plant hormones.
I tell him I have enough food for a few months and not to worry about me. There is shouting in the background, but I can’t make out the words; the call ends, thankfully, before I get invested. I am sensing already that I shouldn’t spend my panic on people I already know. It is easy to forget them; what could I do for them from here?
The sky is sickly green in the evening when the light begins to pulse again.
One-two. It is unmistakably a heartbeat, reborn as two flashes of incandescent plant-flesh, and yet no part of the Bloom could possibly have even a vestigial memory of having a heart. I count eighty beats per minute: a healthy resting heart rate for a human.
One-two. The rate does not change. If it’s a message, it is insultingly simple. There is no hint of frustration, no pleading, no aggression; just a double-tap of light, repeating endlessly. A beacon reporting back that conditions are normal, stand by. One-two. A binary code too flat to be called communication. In Morse code, I recall uselessly, it is just the capital letter I, over and over and over, stupidly iterating into the dark.
I am here. Are you?
I creep to the edge of the Bloom. From the jetty, I drop a rock into its depths, as I often did when the ocean was still liquid, and watch the surface roll away from the impact in a stunted parody of wave motion. If I close my eyes while doing this and pay attention only to the splash, I will remember that there is still water under there.
I squat, scooping a handful of black sand from the beach and letting it pour from my fingers onto the curling leaves of the colony. No ripple at all. The living matter absorbs the motion, stunts its impact, so it can’t be transferred. The motion is born locally, dies locally; sound, spoken prayer, would be stifled the same way.
But the Bloom is connected to itself, somehow. The pulse of the lichen at my feet is perfectly in phase with the pulse at the horizon. Light, then, can cross the channels from one end of the Bloom to the other. The Bloom is not a creature, but a culture; light is its language.
I don’t know any words in light, but I don’t think that would matter, if I could make some kind of deliberate pattern. The intent to speak is its own kind of speech—the astrobiologists taught me that. As long as the signal is clearly meant as a message, it is one.
“Fine,” says K. when she calls back, too early. She woke me up. “Fine. It’s sentient.”
“I told you. There’s no other explanation.”
“Hm.” I can hear her pacing. “Yes. But that doesn’t mean—”
“Why are you so worried? This is a good thing. Maybe we can reason with it.”
“Not good. Unprecedented. Bizarre. I can’t even philosophically wrap my head around it. The pattern makes intelligent life unmistakable. Why would a living being advertise its existence like that? What takes that kind of stupid risk?”
“You’re the one who’s studied it. What do you think?”
She exhales. I can hear her brain working. “I think… whatever it is, it doesn’t know we’re here. Yet. But it’s looking.”
“I’m going to answer.”
“With the beacon? Is it moveable? I thought you couldn’t redirect the beam.”
“I can do it. I just never had to before.”
“Okay. Okay. But D., listen. This is not a conversation with a person. Sentience is not the same thing as a brain. I’ve been studying this thing. It evolves faster than its components, faster even than some viruses, but it also started pulsing all at once, like a single organism… If this is intelligence, it’s clearly distributed—spread out in the body of the Bloom, coordinated, but not centralized. It is nothing like us.”
“What is it like?”
“God. Fuck. I don’t know. An octopus?” She’s close to tears. “Who knows what it would do if it recognized another intelligence? And you want to give away your position, before we even know what will happen! What if it takes the signal as a threat? What if it answers?”
Her voice is so plaintive, so childish, that I half want to shout at her. There is no other option! But I can’t say that. She knows.
For a moment I consider telling her I was planning to come see her when my contract was up, but even thinking the words makes me want to howl.
Instead, I tell K. I love her, and then I hang up in a hurry so I don’t have to hear her sob.
In the evening, I trek north. I weave among my discarded shipping containers, most twice my height, their steel now coated in the rich green of a kudzu infestation at least a foot deep on every face. The vines are flowering on the southeast side where I approach; I breathe in clouds of grape-like perfume as I pass each cluster of white and purple blossoms.
The place steams with life. Between the blocks and everywhere the vines haven’t claimed lies a thick carpet of mosses in varying shades, from pine-green to chartreuse and golden yellow. Already, beneath my boots, the fragile stalks of a bryophyte have been crushed into wet salad.
I need my flashlight to find the ladder on the far side of the tower. I hover on the bottom rung, waiting for the doubts to come; but my wonderful brain is silent, and I hear nothing but the wind through the leaves. The top rung is covered in seagull scat, so I have to haul myself onto the platform beneath the beacon like a sea lion. I turn off my light and recover there for a few moments, with my back against the thin railing, staring upward.
The sky is clear now. The compound lens of the beacon looms over me, its outer rings glittering with reflected stars. The pieces are arranged in concentric circles, like a slice of a giant black onion. Each layer is made of two to thirty segments of gadolinite glass.
It is impossible to tell by sight that the signal is firing. I pass my hand over the opening in the center of the onion slice, and imagine that I can feel it, a sort of metaphysical buzz; but I know I can’t actually feel anything, as surely as I know the signal exists. The beam, even concentrated by my lens, is both silent and invisible to me.
I pull myself up with a groan and stretch upward to run my hands along one of the rings. The dark glass is warmer than I remembered. The smaller rings are closely nested and hard to differentiate by starlight, so I work my way inward by feel. Just below the innermost ring, attached to the pole that supports the beacon’s weight, there is a latched metal box, unlocked.
The terminal inside is still charged. I power it up and it chirps softly, as though it recognizes me. Black letters appear against the green-grey field: I N P U T ?
My mind is empty. I turn away from the beacon and nearly lose my balance. The railing, rusted from the salt spray, groans but holds steady for now. How is it up to me to decide what to say to an alien from my own planet?
It has stopped glowing, I realize as I stare into the sea, so it’s possible I’ve missed my chance, but somehow, inexplicably, I feel that it is actually aware of what I am doing and has simply paused to wait for my answer. Impossible! I can almost hear K. say in response.
I picture her on the other side of the world and feel my spine straighten a bit.
I take great, gulping breaths of the briny air. I reprogram the beacon.
I fiddle with latches in the dark. The lens is twice my wingspan and half my weight, but at least the whole thing comes off its mount without so much as a screwdriver. I hoist it onto my shoulder like a parasol and then lower the circular end to the platform, feeling my long trek across the island screaming in my kneecaps. When I stand up, the beam is pointing just below the horizon, its waves colliding with a distant section of the Bloom’s vast body.
The Bloom is still as stone. In the silvery light, the world looks primordial, as though made of just-cooled magma, unmarred by soil or water. But I know the Bloom is there and watching me, in its own way; it holds its breath as I hold mine.
We watch each other.
Just where the beam hits, a part of the Bloom begins to rise. But this is an illusion: it is simply luminescing, first there and then all over, the whole field of it suddenly turning white with light—far brighter than before. In seconds I’m forced to cover my eyes with my arm, but it’s not enough.
I wake up on the beach a few meters from the tower, my whole body aching from the fall. The world is still flashing around me, so bright I can almost hear the new pattern: the same one I chose moments or hours ago.
Long, short, long. K, the Bloom is saying, shouting, singing, to me and to her, and I can feel her amazement radiating straight through the center of the Earth.