Chapter 43 8.5 Experiments in Persistent Chaos

Bio2 is small compared to Earth, but as a completely self-contained terrarium, its scale is astounding to humans.The giant glass ark of Biosphere 2 is the size of an airport hangar.As for its shape, you can imagine an ocean liner with a transparent body, and turn it upside down.The huge greenhouse is so airtight that even the bottom is sealed—a stainless steel tray is buried 25 feet below ground to prevent air from leaking out of the ground.No air, water, or matter could enter or leave the ark.It's a gymnasium-sized biosphere—a gigantic system closed in matter but open in energy—only much more complex.Apart from Biosphere 1 (Earth), Biosphere 2 is the largest closed living system.

The challenges of creating a living system, large or small, are daunting.And creating a miracle of life as big as Biosphere 2 can only be said to be an experiment carried out in persistent chaos.The challenge we face is to first select thousands of suitable species among billions of components; To maintain; also to ensure that no one organism dominates the mixture at the expense of the other, so that the whole can ensure the constant movement of all its members, without marginalizing any one component; At the same time, it is guaranteed that the entire activity and the composition of atmospheric gases will always remain in a precarious state.Oh, right, people still have to live in it, that is to say, there must be something to eat and water to drink inside, and both food and water must be obtained from this ecological circle.

Faced with these challenges, the SBV decided to entrust the survival of Bio2 to the design principle that the uncommon diversity of the hodgepodge of living organisms can achieve a unified stability.And the "experiment" of Biosphere 2, if it proves nothing else, at least sheds some light on a hypothesis that has been accepted by almost everyone for the past two decades: Diversity ensures stability.It can also test whether a certain level of complexity can give birth to self-perpetuation. As a building with maximum diversity, there are 7 ecoregions (biogeographic habitats) in the final floor plan of Biosphere 2.Beneath a glass dome, a rock-faced concrete mountain plunges into the dome.It is planted with transplanted tropical trees and a misting system: this synthetic mountain has been transformed into a fog forest, that is, a rainforest at high altitudes.The fog forest descends into a highland savannah (the size of a large patio, but filled with waist-high weeds).One side of the rainforest is anchored by a cliff that descends into a lagoon with corals, colorful fish, and lobsters.The highland grasses descended into a lower, drier steppe, dark with thorny, tangled bushes.This ecoregion is called spiny high scrub and is one of the most common habitats for plants and animals on Earth.In the real world, such terrain is almost impenetrable (and thus neglected) to humans.But in Bio2, it provides a small retreat for humans and wildlife.This patch of vegetation leads to a compact, squishy wetland, the fifth ecoregion, which eventually empties into the lagoon.At the lowest point of Biosphere 2, there is a desert about the size of a gymnasium.Because the humidity inside is very high, the foggy plants transplanted from Baja California and South America are planted.On one side of this desert is the seventh ecoregion: a dense agricultural and urban area, where eight modern humans grow food.Like Noah's Ark, there are animals in it.Some are for meat, some are for pets, and some are free: lizards, fish, and birds that roam the wilderness.Plus bees, papaya trees, beaches, cable TV, library, gym, and self-service laundry.Utopia!

The scale of this thing is astonishing.Once I visited their construction site, and there was an 18-wheel semi-trailer truck heading for the office of Biosphere 2.The driver leaned out the window to ask where they wanted the sea, and he had hauled in a truck full of sea salt to unload before dark.Office workers pointed to a large hole in the center of the site.There, Walter Addy of the Smithsonian Institution is building a million-gallon sea, complete with coral reefs and lakes.In this gigantic aquarium, there's just enough compact space for all kinds of surprises to emerge. Building a sea is not an easy task.You can ask Gomez and other amateurs who like to play with saltwater aquariums.Adi once raised an artificial, self-regenerating coral reef for a Smithsonian Institution museum before it opened.However, the sea of ​​Biosphere 2 is extremely large, and it has its own beach.At one end is an expensive wave hair pump that gives corals the turbulence they love.It is this machine that can also produce half-meter-high sea tides according to the cycle of the waxing and waning of the moon.

The driver unloaded the sea: a pile of instant sea water, weighing 50 pounds in packs, like the ones you buy at a tropical aquarium.Later, another truck pulls in a starter solution from the Pacific Ocean that contains the right microbes (similar to yeast for leavening dough), kneads it, and pours it in. The ecologists responsible for building the Biosphere 2 wildlife area belong to a school of thought.They think: soil plus bugs is ecology.To get the kind of rainforest you want, you need to have the right jungle soil.To get soil like this in Arizona, you have to start from scratch.Bulldozer a bucket or two of basalt, some sand and some clay, sprinkle in a little of the right microbes, and mix it in place.The soil beneath all six bioregions in Bio2 was hard-earned in this way. "What we didn't realize at first," says Tony Boggs, "is that soils are alive. They breathe, and they breathe as fast as you. You have to treat soil like a living thing. Ultimately it's Soil controls the biota".

Once you have the soil, you can take on the role of Noah.Noah put everything that moves on his ark, which of course wouldn't work here.The designers of Bio2's closed system kept coming back to the exasperating and exciting question: Which species should Bio2 contain?Now the question is not just "what kind of organism do we need to correspond exactly to the breath of 8 people".The difficult question now is "what organisms should we choose to correspond to Gaia?" What combination of species would produce oxygen for breathing, plants for food, plants for food animals (if any), And the species that feed the food plants?How can we weave a self-supporting web out of random organisms?How can we jumpstart a coevolutionary circuit?

Almost any living thing can be given as an example.Most fruits require insects for pollination.So if you want blueberries in Bio2, you need bees.But if you want the bees to come when the blueberries are ready to be pollinated, you have to let them bloom in other seasons as well.But if you're going to provide bees with enough seasonal flowers to keep them from starving, there's no room for other plants.So, maybe switch to another bee that is also capable of pollinating?You can use Grass Bee, a little flower will feed it.But they don't pollinate blueberries and several other fruits you want.So, what about moths?By analogy, you will have been looking for it in the biological catalog.Termites are necessary to break down dead woody vegetation, but they have been found to eat the sealant around windows.So, where to find a beneficial insect that can replace termites and coexist peacefully with other living things?

"It's a tricky problem," said Peter Warshall, an ecology consultant on the project. "It's pretty hard to pick 100 organisms and put them into a 'wild environment', even from one place." .And here, because we have so many ecoregions, we have to pick them from all over the world and mix them together." To piece together a synthetic ecological region, 6 or 7 ecologists sit down and play the ultimate jigsaw puzzle.Every scientist is an expert in something, be it mammals, insects, birds, or plants.Although they knew something about sedges and green frogs, little of their knowledge could be applied systematically.Warshall sighs, "If only there were a database of all known species, listing their food and energy requirements, living habits, waste products produced, companion species, reproductive requirements, and so on. .But there is nothing even remotely similar to it. We know very little about species that are fairly common. In fact, this project has shown us how little we know about any species."

During the summer of designing the ecoregion, the burning question was: "Well, how many moths does a bat really eat?" In the end, the work of selecting more than a thousand higher organisms became essentially an educated Speculation and some sort of biodiplomacy exercise.Every ecologist has a long waiting list of their favorite, possibly most versatile, and flexible species.Their minds are full of conflicting factors—pluses, minuses, liking being with this guy and not being with that.Ecologists speculate on the competitiveness of biological competitors.They fight to help living things get their rights to water and sunlight.It's as if they are ambassadors, engaged in diplomatic efforts to protect the turf of their chosen species from encroachment.

"My turtles need the fruit that falls from the tree, as much as possible," said Tony Boggs, a desert ecologist on Bio2. Warshall's hummingbirds need to eat fruit flies. Should we plant more trees to increase the amount of remaining fruit, or use the area as a bat roost?" So the negotiation began: If I can get the flower for the birds, you can keep your bats.Occasionally, polite diplomacy turns into outright subversion.The swamp guy wanted his sawgrass pick, but Warshall didn't like his choice because he felt the species was too aggressive and would invade the drylands biome he was tending.In the end, Warshall made a conditional concession to the swamp guy's choice, but added, half-truthfully, "Oh, it's not a big deal anyway, because I'm going to plant some taller elephants Grass to cover your things." The swamp guy retorted that he was about to plant pines, taller than both.Warshall laughed heartily and swore he would plant a fringe of guava trees around the edge as a defensive wall. This kind of tree is no taller than a pine tree, but it grows fast, much faster, and can occupy this area in advance. ecological niche.

Object dependencies make planning a nightmare.One approach ecologists like to take is to create redundant paths in food webs.If there are multiple food chains in each food web, then, assuming the sand flies die out, there are other things that could be food candidates for the lizards.So their approach is not to wrestle with that tangled web of interrelationships, but to discover it.And the key to doing this is to find organisms that have as many alternative capabilities as possible, so that when a certain role of the species fails, it has another way or two to perfect a certain role. Species cycle. "Designing a biome was actually an opportunity to think like God," recalls Warshall.You, as a god, can produce something out of nothing.You can create something—some fantastic, synthetic, living ecosystem—but you have no control over what actually evolves out of it.The only thing you can do is take all the parts and let them assemble themselves into something that works."Ecosystems in the wild are made up of patches," says Walter Adi. "You inject as many species as you can into the system, and then let the system decide for itself which patch it wants to add." In fact, handing over control has become one of the "principles of synthetic ecology." "We have to accept the fact," Adi continued, "that there is far more information in an ecosystem than in our heads. If we try only what we can control and understand, we will surely fail." ’” So, he warns, the precise details of naturally occurring Bio2 ecologies are unpredictable. But the details are what matter. 8 lives depend on these details that form the whole of Bio2.One of the creators of Bio2, Tony Boggs, ordered sand from the dunes for the desert biome to be trucked in, because Bio2 only had sand for construction, and for tortoises, that kind of The sand is so sharp it will scratch their feet. "You have to take good care of your turtles so they can take care of you," he said with a priestly tone. During the first two years of Bio2, the number of organisms running around tending to the system was very small, because there wasn't enough wild food for them to survive on a large scale.Warshall barely puts African baby monkeys like monkeys in there because he's not sure the nascent acacias will provide them with enough to chew on.In the end he put 4 baby monkeys in it, and stored hundreds of pounds of emergency monkey chews in the basement of the ark.Other wildlife residents of Bio2 include leopard turtles, blue-tongued skinks ("because they're generalists"—not picky eaters), various lizards, small finches, and pocket green hummingbirds (in part for pollination). "The vast majority of species are going to be pocket-sized," Warshall told Discover magazine ahead of the closure, "because we really don't have that much space. In fact, ideally we'd be able to fit humans as well." Made it into a pocket." These animals were not put in pairs. “For reproduction to be guaranteed, there should be a higher percentage of females,” Warshall told me. "In principle, we want to have a 5:3 ratio of females to males. I know that the 8 individuals that Director John Allen said - 4 males and 4 females - is the minimum size for human colonization and reproduction , but from an ecological rather than a political point of view, the Bio2 crew should actually be 5 women and 3 men." For the first time ever, the puzzle of creating a biosphere has forced ecologists to think like engineers: "Now that you have everything you need, what materials will you use?" The engineers of this project have to think like biologists: "This is not soil, this is a living thing!" One of the intractable problems for Bio2's designers was making rain for the foggy forest.Rainfall is hard.The original plan was optimistic, with cooling pipes at the top of the 85-foot-tall glass roof covering the jungle section.These condensation tubes condense the humidity in the jungle, forming gentle raindrops that rain down from the zenith—true artificial rain.But early tests have shown that the rain this way gets very infrequent, and when it does, it's too big and too damaging to be the gentle, constant rain the plants were supposed to need.A second plan to harvest rainwater, which relied on sprinklers fixed to the overhead frame, turned out to be a maintenance nightmare: over a two-year period, the sprayers, which were drilled with finely sized holes, , will definitely need to be unblocked or replaced.The final design solution is to install water mist nozzles at the ends of the water pipes scattered on the slope, and then spray "rainwater" from these nozzles. Living in a small material closed system, one thing I did not expect is that not only is there no shortage of water, but it is also quite abundant.In about a week, all the water completes a cycle, being purified by the activity of microbes in the treatment area of ​​the wetland.When you use more water, you're just slightly speeding up the flow of water into the cycle. Any area of ​​life is woven by countless independent circuits.The circuit of life - the route followed by matter, function and energy - overlaps and interweaves in a haphazard manner, forming an inextricable knot until the veins cannot be discerned.All that emerges is the larger pattern woven by these circuits.Each loop makes the other loops stronger until they form a whole that is difficult to unravel. That's not to say that extinctions don't happen in tight-knit ecosystems.A certain extinction rate is necessary for evolution.When working on partially enclosed coral reefs, the species loss rate obtained by Walter Addy was about 1%.He estimates a 30-40% decline in species across Bio2 by the end of the first two-year cycle (as I write this, Yale biologists have not yet finished losing species study, currently taking an inventory of species after Bio2 reopens.) But Ady believes he has learned how to breed diversity: "What we've done is we've crammed in more species than we'd hoped to survive. The rate of attrition will go down. Especially insects and low-lying species. Wait for the creature. Then, when the new round starts again, we overfill it again, but with a slightly different species—this is our second guess. What might happen is, This time there will still be a large percentage loss, perhaps a quarter. But we will re-inject the next time we shut down. Each time, the number of species will stabilize at a slightly higher level than the last time. And the system The more complex it is, the more species it can hold. As we keep doing this, diversity builds up. And if you take all the species that Bio2 can hold at the end, put it in the first Get in, and the system breaks down in the first place." It can be said that this huge glass bottle is actually a variety pump-it can increase variety. A huge question left for Bio2's ecologists is how best to jumpstart initial diversity so that it becomes a lever for subsequent growth in diversity.And this problem is closely related to the practical problem of how to fit all the animals on the ark.What do you have to do to cram 3,000 interdependent creatures into a cage -- and still be alive?Adi once put forward such a suggestion: to compress the entire ecological biome by abbreviating a book, and then move it into the relatively reduced space of Biosphere 2, that is to say, to select the essence scattered everywhere, Then fuse them into a sampler. He selected a 30-mile stretch of fine mangrove swamp in the Everglades area of ​​Florida and surveyed it wall by wall.Dig small squares of mangrove roots (4 feet deep by 4 square feet) approximately every half mile along the salt gradient.The samples of leafy branches, roots, mud, and attached barnacles were crated and pulled ashore. These swamp samples were taken in sections, each with a slightly different salt content due to slightly different microorganisms in it. There are different.After lengthy negotiations with some agricultural customs officers who mistook the mangroves for mangoes, the swamp samples were shipped back to Arizona. While the clods of mud from the Everglades waited to be dropped into the Bio2 swamp, Bio2 workers hooked up watertight tanks and a network of pipes to form a distributed salt water tide.About 30 cubes were then relocated inside Bio2.Out of the box, the re-formed swamp takes up a tiny 90x30 feet.But every part of this volleyball-court-sized swamp is home to a growing mix of halophilic microbes.In this way, the flow of life from fresh water to salt water is compressed into an unremarkable range.For an ecosystem to take an approach like this, scale is part of the key question.For example, as Warshall tinkered with the parts used to create a mini-savanna, he shook his head and said: "We've moved, at most, about one-tenth of a system's species into Bio2. No. As for insects, it's closer to 1 percent. In a savannah in West Africa there are 35 species of bugs. We have three at most here. So, the question is: are we doing savannah or Doing the lawn? Of course it is better than the lawn... but how much better it is, I don't know."