Floating Forests of Venus

The surface of Venus is a hellscape, akin to a superheated, gloomy, dry deep sea, where only the strangest of extremophiles manage to carve out an almost impossible existence. But high up in the clouds it is as if one flies through a wondrous dreamscape of another world entirely. Instead of just succumbing to the deterioration of their homeworld and quietly go into extinction, the ancient lifeforms of our twin planet did the impossible and colonised the skies.

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Aided by a superdense atmosphere, which makes floating and flying easy even within an Earth-like gravity, giant aerial reefs float here, sometimes forming complex systems large enough to be seen from orbit, maybe even Earth-based telescopes. Some of these floating islands can almost grow to the size of Madagascar. On their backs grow then entire forests and jungles, inhabited by grotesque primordial beasts, strangely evoking still Svante Arrhenius’ failed prediction of Venus as a planet stuck in the Carboniferous period.

How do these floating islands form? The main reef builders are obviously buoyant animals and plants, which make use of the planet’s unique atmosphere to feed on the abundant aeroplankton. The most prominent of these are worms of the family Pulmoserpulidae, which resemble an unmineralized fusion of an ammonite and a crinoid. These serpulids begin life as larvae floating in the air, held up by an air sac in the tail-base. While maturing, two small tentacles at said base secrete a chitinous membrane, which, similarly to Earth’s paper-nautilus, eventually develops into a coiled shell filled with additional air chambers that help hold the growing organism afloat. From such a base then hangs a long tube with feathery tentacles at the end, with which the serpulids filter-feed the air for plankton. What makes these worms essential ecosystem engineers is that they are colonial and encrusting. As larvae they will cling to any surface and cement themselves with their shells on there like barnacles. Usually, the first thing they cling to are their siblings, thus forming large floating balls of shells and tentacles. Onto these then graft more serpulids and other floaters, which widens the ball’s surface, thus allowing even more floaters to encrust themselves onto it. Eventually the base of a floating island is formed. Often, these will break up again due to violent storms, acid rains, reef-breaking carnivores or lightning strikes, but some islands do grow large enough that they can remain stable in the air even during adverse weather conditions and reproduce fast enough to fix holes and gaps.

Once such bases have been formed, airborne spores will settle upon them, eventually growing into lichenous, fungal growths and low, moss-like coverings. Some of these subsist solely on aerial detritus and rain settling on the islands from above, some form endosymbiotic relationships with the floaters they grow on. Some are also parasitic, boring through the shells of the serpulids to tap into their water and nutrients. Some of these parasitic fungoids can thus cause damage to the reef’s gas balance, causing it to sink into the inferno below. But such parasitic outbreaks are rare, likely due to the natural selection of such a self-destruction. Very crucial during the first phase of colonization are also flying animals which form nesting colonies on the barren islands. During their roost, they defecate and leave plenty of guano behind, providing an important source of nutrients for the nascent ecosystem. Over time, guano, aerial detritus and the decaying biomass of dead moss and fungi will accrue so much that the island gains its first proper soil layer. Alerted by statocysts inside their bodies, the floaters below will usually compensate for the added weight by just growing more air chambers.

With the formation of a proper soil, seeds can now settle and grow into small plants, which in turn offer cover, habitat and food for small, insectoid aerial organisms, who in turn become food for other animals. With this secondary ecosystem accumulates eventually enough detritus that the whole island will become covered in a rich layer of soil thick and firm enough that one could believe they are standing on solid ground. At this stage the seeds of larger plants will now begin to take root, growing into tall trees and eventually forming a forest cover. A beautiful one at that. One cannot help but stand here mesmerized by this natural wonder, listening as the gentle wind caressing the foliage composes a magnificent stickerbush symphony.

At this stage larger animals will begin to make their homes here, often by flying or gliding over from other islands. Sometimes two or more islands will also simply bump into each other, allowing for easy dispersal. Here we see one such fellow, a dyrokong, clambering even through the thick forest of vines beneath his island. With four long limbs and grasping arms it is easy to compare this creature to an ape, like a gibbon or orang, though like a flying squirrel it also bears a pair of gliding membranes between its extremities. In such an environment, where one slip may mean hellfire, it makes sense to not rely on climbing skills alone. Kongs are part of a major Venusian phylum, the Sclerocephala, which superficially resemble vertebrates. Except for the head, that is. Their eyes are mineralized and are made up of heavily ossified scleral rings, visible even in the living animal. Perhaps an adaptation towards high pressure? Their fleshy jaws also open horizontally, sometimes assisted by a dextrous tongue. Little is known about the behaviour of dyrokongs, so one wonders if they are maybe also up to jungle hijinks like their Earth-pendants.

As he brachiates from worm to worm, he needs to watch out, for not all is as it may seem. Among the floaters can also hide carnivorous plants(?) like the Medean clam, which disguise their grasping tentacle as a serpulid. Should climbing or flying animals grab it, they will become ensnared in the mucus and slowly lifted up into the mighty jaw, where they will be slowly digested alive.

Other dangers lurk here too, for the skies are filled with plenty of aerial predators ready to snatch an unwary islander off their home. Like this Sphyraenops, which resembles a flying deep-sea fish. It is a member of another major phylum, Eurypharynxia. These resemble terrestrial vertebrates even more, though they tend to have a multitude of eyes and their jaw-hinges extend in almost all forms far behind the actual skull, giving them the nickname gulperfish or, in the more derived forms, gulpersaurs. Another distinction is that they breathe and smell not through nostrils but through a sort of blowhole at the back of the skull, which in some derived forms extends into a hadrosaur-like crest. Due to some of their paradoxically aquatic characteristics, it has been hypothesized that the gulpers may ultimately descend from actual deep sea organisms, which, as Venus slowly lost its oceans, likely were among the last animals living on the surface with enough time to adapt to the dramatic changes.

In the flying fish’s ravenous sight is a little, unassuming furball. This is a therorb. Not much is known about these animals beyond that they are small, have a single eye, a beak, thin, bird-like legs and are covered in fur. They hold the unique distinction of being among the few Venusian organisms known to be homeothermic. Almost all other larger lifeforms are poikilotherms, not needing a stable, high metabolism thanks to the high temperatures of Venus even far up in its atmosphere. Its role in these surreal ecosystems could perhaps be compared to that of the archaic mammals of Earth’s Mesozoic. In its own, twisted way, our twin planet still seems to be firmly in the grips of its own Age of Reptiles.

For the ruling class in these forests are strange beasts such as this. Phalacromimus is a more derived member of the eurypharyngians, specifically from the fearsome order of the Ornithosauria. Likely descending from bird-like, leathery-winged creatures, many of the ornithosaurs indeed resemble bizarro-versions of the dinosaurs and pterosaurs of ancient Earth. And not the lethargic and cumbersome ones of your old picture books, rather the newer, agile and dangerous ones. Ornithosaurs are still technically poikilotherms, due to not having a consistent body temperature, but can heighten their metabolism when needed, creating a flexible middle ground between warm- and cold-bloodedness. Phalacromimus is a fairly unassuming fellow, flying and nesting between the islands and snatching up small prey like the therorb much in the manner of a pelican. Compared to its fearsome cousins it seems downright adorable. From larger “landmasses” some cosmonauts have reported terrifying beasts, as large as shuttles, some of which have even given up the extraneous ability to fly in order to live permanently in their floating jungles. Among these reports is a creature called the “Lacerodactyl”. While officially a “cryptid”, due to still awaiting official scientific documentation, it does have a confirmed kill-count of 14 unlucky spacefarers. Descriptions make it seem like a featherless Deinonychus, agile and intelligent, with the oversized head of a barracuda. Footprints, scattered bones and lidar-scans also attest to the possible existence of carnosaur-sized beasts somewhere within the larger jungles.

Most numerous, yet also most enigmatic among the Venusian fauna are the millions of small flying insectoid creatures. Some of them hide elegantly among the vegetation like stick-insects. Others are mesmerizing little flyers resembling airborne millipedes.

Even more mysterious are organisms which seem to have never had airborne ancestors, such as this hammerolm, a serpentine eurypharyngian with vestigial hindlegs. Did it maybe have wings once, but lost them so long ago that all traces have been lost? Or was there a window of time where aerial islands already existed when the surface was still habitable, maybe allowing some animals from mountains or high trees to hop on? We can only speculate.

Next to gulperfish, other flying predators abound. Patrolling here is an angaros, part of the sclerocephalian order of the Aerolamnii or “windsharks”. Giving live birth, these can spend their entire lives in the air, having no functional legs anymore and only coming to rest on the islands when sick or injured. Some are solitary, but a few species have proven quite intelligent, able to attack in packs on the titanic aerial filter-feeders which sometimes pierce through the clouds. How they coordinate amongst each other remains to be researched, though our sonar equipment sometimes becomes disturbed by strange signals that may stem from these creatures.

The upper atmosphere of Venus is the most Earth-like of any of our neighbouring planets, far more so than the one on Mars. A human may in theory survive here with only a gasmask on. Some have thus speculated that these floating islands may indeed be the next step of human space colonisation instead of the barren wastes of the red planet. What further facilitates this is the surprising fact that the biospheres of Earth and Venus are compatible. Unlike the decidedly alien lifeforms of Mars, Venusians are made of the same stuff as us, encode their genes in DNA and their microorganisms have an undeniable resemblance to Earth’s Archaea. The chance that this is due to a mere cosmic coincidence is astronomically unlikely. Instead, somewhen during the deepest Precambrian eons, one or maybe even more panspermia events must have taken place which seeded one planet with life from the other. Which planet originated life first is a question for the ages that we can debate at a later date. While for now this means that humans run the risk of potentially being infected by Venusian pathogens (or vice versa), one can imagine that with enough time and genetic engineering, a man from Earth may indeed one day enjoy the fruits of Venus or maybe even plant his own crops in the aerosoils. If he is also capable of managing the acid rains and prehistoric monsters, that is…

The Soviets have indeed already attempted to build bases on the islands, claiming they are solely there for research into exobiology and colonisation. As is now well-known, however, the main purpose of these bases was to develop and build potential superweapons away from the prying eyes of the global community. Back in my younger years, when I was still working for the MI6, I had some… direct experiences with these facilities. But if I told you those stories, I would have to kill you. And I still have the license for that.

Awbar

When people think of extinct life, they usually have images of fossils and artistic reconstructions in their head. Extinction is a phenomenon seemingly relegated to the far past, to dinosaurs and mammoths. In reality, extinction happens all the time, throughout the present. It is a process as natural as life and death itself. Yet, it leaves us mourning when it happens in front of our own eyes.

The awbar were a fascinating species which the first astronauts encountered on Mars, including myself on some of my early missions. They lived in a peculiar area of the Argyre Basin. Mars lacks a global magnetic field like Earth does, making it an all-around more irradiated and hostile place. However, some areas contain highly magnetized rock formations, which have managed to save some remnants of the prehistoric magnetosphere, creating local shields against UV and other harmful radiation from space. In these so-called UV-oases, flora and fauna can lead a more sheltered life and attain higher biodiversity than in other areas of the planet. The awbar lived in one such oasis - only one – together with the organisms it depended on.

The awbar is thought to have been a goniopod, a group of dinosauresque deltadactylians, but unlike its bigger cousins, the cecrops and syncarpus, it was generally not included within the more exclusive Thecocerata, as it lacked the characteristic hornlets inside of its beak. This decision has often been criticized, as the lack of that trait may instead have resulted from its specialized diet. Other unique traits were that it felt comfortable walking both on two and three legs and that it exhibited multioculy (having more than two eyes), a trait otherwise rare in goniopods.

It was a nimble creature, able to fit inside a human hand. From its back grew a fleshy fin, adorned with a peculiar oval spot. Undoubtedly this served some display function, but what exactly is now forever uncertain. Awbar lived in close association with a plant dubbed the sporangobush, a type of fractarian. Its sporangia ended in hairy bulbs, each hair drenched in some kind of viscous liquid. Awbar were most often seen climbing up the bushes and licking these furballs with their long, retractable tongue. Many authors have assumed that this could have been a symbiotic relationship. Assuming the liquid produced by the sporangia was some kind of nectar, the Martian may have been lured into licking up the plant’s spores. Inside the stomach and guts of the creature, these spores may have combined with those of other sporangobushes and exited the body through excretion, already fertilized. It is impossible to test any such hypotheses anymore, however. There may not have been a mutual benefit at all to such behaviour, the creature could have been licking the sporangia for reasons entirely unintended by the plant. Perhaps the liquid was toxic or unappealing to some herbivores but was unintentionally alluring to the little creature, the same way spicy plants on Earth have unintentionally garnered the attention of humans. Or the relationship between the organisms was much more intricate and complicated than we can ever imagine, seeing as how little we still know about these ecosystems.

The extinction of the awbar was not brought about by a catastrophe like the dinosaurs’ or through human interference like the dodo’s. It was the end of a slow process already well on its way long before man set his foot on the red planet. The magnetization held within the surrounding rocks had simply begun to fade. With each passing year, the local magnetosphere grew weaker and more radiation reached the soil. The changes must have been incremental at first. With each blooming, the number in each organism’s generations must have grown less, rates of cancer and other ailments must have risen and gradually lowered their lifespan. The margins and tall hills of the oasis became barren first, the eggs of the sporangobushes and tube-cycads in the soil simply failing to germinate. These blank spots were then quickly colonized by more UV-resistant flora and planimals from outside the region, like chiropedes and the aggressive red weed. From that point on, the collapse of the previous ecosystem progressed at a geometric rate, as now the local organisms did not only face environmental degradation but also competition from outsiders they would have normally been able to outbreed. Local nekhbets failed to spawn and were gradually replaced by wadjets and more delicate spongisporians died from mutations before they could bloom, losing ground to their thorny upland counterparts. The ecosystem transformed and many were simply not able to adapt quickly enough to the changes. It was a prolonged evolution of the landscape, observed by us humans over a span of about twenty years. When the shield was finally gone, very little remained of the previous ecosystem. The last sporangobushes failed to reproduce and aged into misshapen mutants before mercifully fading away. The last awbar was already sighted five years before their extinction.

It is a curious feeling, to know that these little creatures used to crawl over my feet one day and are now forever gone. Though less spectacular than the great fossils dug out from the ground, their loss is a much more personal one. A more painful one. It is the difference between reading about Abraham Lincoln’s assassination in a schoolbook and seeing your own father pass away at the hospital. The many questions you ask yourself. Was this inevitable? Were there ways I could have helped? Why didn’t I try to help? Why did I not do more with the time we were given together? But such things, speculating about changing a past that can no longer be changed, hypothetical realities, is a futile misery. There was nothing I could have done. The magnetized rocks would have faded regardless of me being there or not and none of our expeditions were ever equipped to preserve species. We were just there to observe and study. And by the point I knew my father was sick, it was already too late for us to bond in the way be both wished we would have. Years of neglect had eroded any emotional foundation that could have been built upon. He was my father, and a good one at that, but he was never my friend.

Red Weed

On Earth, a view of plant life may envelop a person in warm, serene feelings. Plants are organisms we take for granted as helpful, passive creatures, sometimes even viewing them as if they exist solely for our own purposes, more tool than lifeform.

On Mars, a view of the local flora may cause, if it is capable of feeling, a sense of dread in the local wildlife. Perhaps in the distant past, the vegetables of this planet used to be just as passive and generous as our own, but millions of years of environmental deterioration have made even the flora savage. In the last savannah can be found giant, sponge-like growths that digest microorganisms from the air in cavernous guts while in the sparse shrublands there are bushes that send out their offspring to feed on other plants.

Arephyta, the Martian taxon most similar in morphology to Earth’s Plantae, once used to make up the majority of the planet’s flora, as the fossil record attests. But unlike our planet’s algae and plants, arephytes never evolved oxygenic photosynthesis. They are stuck with a much more archaic metabolism, where sunlight is used to turn hydrogen sulphide and carbon dioxide into sugar, the waste-product being elemental sulphur instead of oxygen. When Mars was young, this dependence on H2S was no problem. Volcanoes regularly nourished the atmosphere with sulphuric gases while the waterways and wet soils were likely filled with microscopic sulphate-reducers that created H2S as a waste product. But as the planet has aged and dried, so have the conditions which have allowed these organisms to flourish. Many arephytes have gone extinct eons ago, the last survivors of the most basal types now desperately cling to the hangs of volcanoes and hot springs, where conditions still provide a faint echo of the elder days. The thrones of the plant kingdom have been usurped by former “planimals”, the spongisporians and fractarians, which have bet on the right horse and engage in symbiosis with oxygen-producing chloroplasts.

However, one group of arephytes has managed to adapt to this changing world. Arthrophyta is a clade characterized by bilateral symmetry and segmentation, traits we usually associate with animals. But the major characteristic that differentiates them from their archaic forebearers is that they have gained an additional type of endosymbiont: sulphur-reducers. These are anaerobic areont-cells that the plant houses in tightly-sealed bulbs along its stem. The deal is simple: The plant provides anoxic conditions inside its body and waste-sulphur, the symbionts reduce this sulphur back into hydrogen sulphide. An ingenious cycle. With this, the arthrophytes have been able to maintain a wider distribution than their cousins, and in the past grew into their own forests in a world already dominated by fractarian scale-trees. Still, they were and are limited compared to their competitors. Being able to recycle one’s own sulphur is an excellent adaptation, but it is not truly the same as producing H2S. It is a closed cycle and so the arthrophytes are still dependent on any additional hydrogen sulphide they may receive from the soil.

One peculiar group of arthrophytes has found a solution to this problem: Carnivory. The ancestors of this group likely started out not unlike Earth’s sundew, growing in nutrient-poor soils and trapping smaller animals as an extra-source of nitrogen. As they did, putrefying microorganisms must have fermented the sulphurous molecules of the prey’s body and created waste H2S, which immediately came in handy. Over millions of years a close endosymbiosis was forged, which eventually resulted in diets far more sophisticated and terrifying than that of any venus flytrap on Earth.

When an animal steps into the tentacle-like leaves of the red weeds, it immediately becomes ensnared, each attempt at escape triggering more proto-nerve reactions in the plant to hold onto the prey firmer, eventually tiring and choking it to death. In an ordinary carnivorous plant from Earth, this is where digestion would already begin, with enzymes secreted from the plant surface decomposing the food. But these plants digest their prey with microorganisms inside their body, in fact in the anaerobic chambers that formerly housed the sulphur-reducers, now transformed into something that could be called a true stomach. And it is by the method that these plants get food to their stomachs that they have earned their sinister reputation… and colour. These are vampire plants. Each leaf is adorned by tiny needles, much like the hairs of Earth’s stinging nettle, but instead of injection, these needles are adapted towards suction. Through osmotic processes, a pressure difference is created between the stomachs and the veins leading up to the needles. Once a prey animal breaks away the needles’ seal and gets stung, they work like syringes and draw out the blood and other fluids from the organism, sucking it dry over time. It is a gruesome process, sometimes an audible slurping sound has been recorded by observers. Some plants even inject their prey with an acid that aids in decomposition of body tissues into a digestible sludge, much like a spider. The nutrients from the victim’s fluids are digested in the stomachs, leading to the production of H2S, nitrogen and other helpful resources. The excess water now courses through the predator’s xylem, an excellent boon when living in the dry wastes of Mars.

Due to the abundance of iron in the planet’s crust, many of the higher animals use haemoglobin, myoglobin and erythrocruorin to transport oxygen, much like many organisms on Earth do. This means their blood is likewise red and, now stolen, tints the natural colour of these arthrophytes from the inside. As many of their metabolic pathways do not require oxygen, it remains unknown what the plants use the globins coursing through their vessels for. Its colour, together with its aggressive, choking nature, is how the plant has earned its colloquial name: Red Weed.

By going on the offensive, these remnants of a forgotten flora have burned their way across the ecosystem, growing with an astonishing vigour and luxuriance. Whole areas of the sparse shrublands have become their own microbiome where the cactus-like red weeds form dense carpets and miniature carmine forests. Many different species and morphologies exist. Some have the typical broad, tentacular leaves like a sundew, others broadcast long, thin strings from their stems almost like tripwires. The latter’s tendrils creep like slimy, wet animals across the wasteland, covering field, ditch, shrubs and sleeping animals with living, scarlet feelers, crawling, crawling… A third type of red weed, the vampire-waterlilies, is only very rarely encountered, as it lies dormant for most of the year. But during the thawing season, wherever this extraordinary growth encounters a stream of water it straightaway becomes gigantic and of unparalleled fecundity, clinging and growing with frightening voraciousness. Its diaspores are simply poured down into the water to be deposited and covered into the sediment for the next season and its swiftly growing and titanic water fronds speedily choke the water, creating transitory pools in which amphibious creatures lay their spawn.

The greatest differences between the species usually lie in the “heads” of the plants, which are their reproductive organs. Something akin to the beautiful flowers or fruit has never evolved on Mars among any of the known flora. Instead, sickening sporangia grow from these sickle-shaped tops, dispersing wretched diaspores into the wind and soil. Some of the red weeds’ diaspores can be necroparasitic if they are ingested. Usually, they lie dormant inside the host’s tissue for its entire life, but when it finally dies of natural causes, putrefying chemicals will cause the diaspore to germinate and feed on its host’s corpse until bursting out of the decaying body. A very few do not wait for the host’s death.

Another advantage of the red weeds is that very few herbivores feed on them, usually due to the damage that their needles may cause on mouthparts but also because most herbivorous animals seem to find it unpleasant to bite into food filled with other animals’ blood. But there are a few that do feed on the red creepers, helping to keep their advance at bay. Bennus, rannus and other periostracans have solid scolecodont beaks formed out of former teeth and so are immune to the syringes’ stings. They simply bite into the leaves and rip them out, destroying any built-up osmotic pressure, and then chew with pleasure on the succulent snack. Perhaps they do not mind the taste due to their own omnivorous diet. Some onychognaths also have beaks, but the soft inner-linings of their mouths still make it difficult for them to bite into red weeds.

On a final note, it is interesting to discuss why such a type of carnivorous plant has not evolved on Earth, even though all the required mechanisms theoretically exist in our own flora. It is most likely a question of necessity, none of the oxygenic earth-plants needing to evolve such drastic measures like the metabolically impaired arephytes to stay in the evolutionary game of life. But it could also be a question of time. Carnivorous plants on Earth are only a recent phenomenon, most fossil and molecular evidence pointing towards an origin not older than the Late Cretaceous. Perhaps the humble sundew and the flytrap are still at a very early stage of their kind’s evolution. As Earth itself will inevitably sink in habitability and competition from the expanding C4 plants will drive such forms into harsher habitats in another 500 million years, perhaps strategies just as drastic if not more extreme than those of the red weeds will evolve here too. In a billion years, when the expansion of the sun has turned our home into another red desert, this will maybe also become a planet of vampire weeds. Perhaps they will even sprout legs and go by themselves on the hunt for the animalistic post-humans that will cling to the wasteland.