Chapter 47 9.3 Intentional seasonal adjustments

In this super-sealed world, hundreds of times more airtight than any NASA capsule, the atmosphere is full of surprises.First, the air is surprisingly pure.The collective respiration of the wilderness eliminates the problem of trace gases that accumulate in previously enclosed habitats and high-tech closed systems like NASA's space shuttles.Some unknown balancing mechanism (probably caused by microorganisms) has purified the air here, making the air in Bio2 much cleaner than in any space traveler to date.Mark Nelson said, "Someone has calculated that in order to ensure that an astronaut can survive in a space capsule, it costs about 100 million U.S. dollars a year, but the living environment is unimaginably poor, even worse than a slum." I mentioned one of his acquaintances who had the honor of welcoming returning astronauts.She waited excitedly in front of the camera as they prepared to open the cabin.They opened the hatch, and a foul smell hit her, and she threw up.Mark said, "These guys are really heroes, and they survived such a bad environment!"

For two years, CO2 levels in Bio2 fluctuated from high to low.On one occasion, it was cloudy for six consecutive days, and the carbon dioxide level was as high as 3800ppm.Let us look at a set of comparative figures: the carbon dioxide content in the external environment is usually kept at about 350ppm; in the modern office in the downtown area, the carbon dioxide content may reach 2000ppm; The CO2 level in the air reaches 8000ppm; the "normal" level of CO2 in the air of the NASA space shuttle is 5000ppm.In contrast, Biosphere 2's average daily carbon dioxide content of 1,000ppm in spring is quite good; the fluctuation of carbon dioxide content is also completely within the range of changes in ordinary urban living environments, and the human body is almost imperceptible.

Fluctuations in atmospheric carbon dioxide levels do affect plants and oceans, though.During the days when the CO2 levels were tensely high, biospherians worried that the increased CO2 in the air would dissolve in the warmer seawater, increasing the carbonic acid ratio in the water, lowering the pH of the water, and harming newly transplanted corals.Part of Bio2's mission is to understand the further ecological impacts of increased carbon dioxide. The composition of Earth's atmosphere appears to be changing, which has attracted attention.But we can only be sure that it changes, and beyond that we know next to nothing about how that change manifests.The only accurate measurements in history have been related to only one factor - carbon dioxide.Relevant data show that in the past three decades, the carbon dioxide content of the earth's atmosphere has been rising at an accelerated rate.The graph was drawn by a single and persistent scientist, Charles Keeling. In 1955, Keeling designed an instrument that could measure carbon dioxide levels in any environment, from sooty city rooftops to pristine barren forests.Keeling obsessively measured every place where he thought carbon dioxide levels might have changed.He measured day and night, and initiated ongoing efforts to measure carbon dioxide levels on Hawaiian mountaintops and Antarctica.A colleague of Keeling told reporters, "The most distinctive thing about Keeling is that he has a strong desire to measure carbon dioxide levels. He thinks about this matter all the time, whether it is carbon dioxide levels in the atmosphere or in the ocean. He wanted to measure. He's been doing it his whole life." To this day, Keeling is still measuring carbon dioxide levels around the world.

Keeling discovered early on that the amount of carbon dioxide in the atmosphere varies periodically from day to day.At night, plants stop photosynthesis for a day, and the carbon dioxide content in the air increases significantly; in the afternoon on a sunny day, because plants try their best to convert carbon dioxide into nutrients, the carbon dioxide content will reach a low point.A few years later, Keeling observed a second cycle of carbon dioxide: a seasonal cycle in the northern and southern hemispheres, with summer low and winter high, for the same reason as the diurnal cycle, because green plants stopped feeding on carbon dioxide.Keeling's third discovery focused attention on changes in atmospheric dynamics.Keeling noticed that no matter when and where, the lowest concentration of carbon dioxide will never be lower than 315ppm.This threshold is the background value of global carbon dioxide levels.In addition, he noticed that the threshold has been raised a little bit every year, and today, it has reached 350ppm.More recently, other researchers have identified a fourth trend in carbon dioxide in Keeling's meticulous records: the increasing magnitude of its seasonal cycles.It is as if the planet breathes once a year, inhaling in summer and exhaling in winter, and it breathes harder and harder.Is the goddess of the earth taking a deep breath, or panting?

Bio2 is Gaia in miniature, a small self-enclosed world with a miniature atmosphere created by the creatures that live within it.This is the first complete atmosphere/biosphere laboratory.It has the opportunity to solve scientific mysteries about how Earth's atmosphere works.Human beings enter this test tube to prevent the experiment from collapsing and help it avoid some obvious crises.The rest of us, while outside of Bio2, are inside the big test tube Earth.We're messing around with Earth's atmosphere without knowing how to control it, where its regulators are, or even if the system is really out of tune, if it's really in crisis.Bio2 could give us clues to answer all these questions.

Bio2's atmosphere is so sensitive that even just a passing cloud can raise the carbon dioxide needle.The shadow instantly slows down the photosynthesis of plants, temporarily blocks the inhalation of carbon dioxide, and immediately reflects it on the carbon dioxide meter.On partly cloudy days, Bio2's CO2 graph would show a series of spikes. Despite all the attention paid to atmospheric carbon dioxide levels over the past decade and agronomists scrutinizing the carbon cycle in plants, the fate of carbon in Earth's atmosphere remains a mystery.Climatologists generally agree that in the current era, the increase in carbon dioxide levels matches the rate at which industrial humans are burning carbon.This pure correspondence ignores a shocking factor: after more precise measurements, we found that only half of the carbon burned on Earth today remains in the atmosphere, increasing the concentration of carbon dioxide, and the other half disappears!

There are many theories about the disappearance of carbon, and there are three dominant ones: (1) dissolve into the ocean and sink to the seabed in the form of carbon rain; (2) be stored in the soil by microorganisms; (3) the most controversial theory is: The missing carbon spurs the growth of grasslands, or morphing into trees, on a scale so invisible and gigantic that we can't yet measure it.Carbon dioxide is recognized as a finite resource in the biosphere.When the carbon dioxide content is 350ppm, its concentration percentage is only a weak 0.03%, which is only a tracer gas.A cornfield in full sun can deplete carbon dioxide within three feet of the ground in less than five minutes.Small increases in carbon dioxide levels can also significantly boost biomass.According to this hypothesis, in forests where we have not yet deforested, trees are "gaining weight" rapidly due to a 15% increase in carbon dioxide "fertilizer" in the atmosphere, and the rate may even be faster than the rate of destroying trees elsewhere much.

The evidence so far has been puzzling.However, in April 1992, "Science" magazine published two research reports, declaring that Earth's oceans and biosphere can indeed store carbon on the required scale.One of the articles showed that European forests had gained more than 25 percent of their timber volume since 1971, despite the negative impact of acid rain and other pollutants.However, examining the global carbon budget in detail is not easy.Given our ignorance of the global atmosphere, experiments in the biosphere give us hope.In this sealed glass vial, under relatively controlled conditions, we can explore the connection between a dynamic atmosphere and an active biosphere.

Before Bio2 shut down, carbon levels in its air, soil, plants, and seas were carefully measured.After sunlight stimulates photosynthesis, a certain amount of carbon is transferred from the air to the organism.Therefore, every time a plant is harvested, the biosphere people painstakingly weigh and record it.They can watch how the carbon distribution changes with tiny disturbances.For example, when Linda Leigh "stimulated the savannah" with an artificial summer rain, the biospherians simultaneously measured carbon levels in subsoil, topsoil, air, and water.At the end of the two years, they produced an extremely detailed chart showing all the carbon distribution points.They also tracked the movement of carbon through this simulated world by keeping dry leaf samples and recording changes in the ratios of naturally occurring carbon isotopes.

Carbon is just one piece of the puzzle.And the other mystery was even stranger.The oxygen content inside Bio2 was lower than outside, from 21% to 15%, a drop of 6%.This is equivalent to relocating Bio2 to higher altitudes and thinner air.Residents of Lhasa, Tibet live in a similar low-oxygen environment.Biospherians thus experience headaches, insomnia and fatigue easily.Although not a catastrophic event, the drop in oxygen levels is puzzling.In a closed bottle, where does the lost oxygen go? Unlike the loss of carbon, the loss of oxygen in Bio2 was completely unexpected.It has been speculated that the oxygen in Bio2 was locked up in the newly modified soil, possibly captured by microbially produced carbonates.Or, possibly absorbed by the fresh concrete.In a quick search of the scientific literature, biosphere scholars found that data on the amount of oxygen in Earth's atmosphere was woefully scant.The only known (but hardly reported) fact is that the oxygen in Earth's atmosphere is probably also disappearing!No one knows why, nor how much is missing."I am astounded that people all over the world are silent. No one wants to know how fast we are using up oxygen," said visionary physicist Freeman Dyson, one of the few One of the many scientists who asked this question.

So why stop there?Some experts who observed the Bio2 experiment suggest that the next step should be to track where nitrogen comes from and where it goes.Although nitrogen is a major component of the atmosphere, its role in the general cycle is only partially understood.Like carbon and oxygen, its current understanding comes from reductionist laboratory experiments or computer models.Others have suggested that the next step for biospherologists is to measure sodium and phosphorus.Probably the most important contribution Bio2 made to science was that it raised many important questions about Gaia and the atmosphere. When carbon dioxide levels in the biosphere first rose sharply, biospherians took countermeasures to limit the rise in carbon dioxide. "Intentional seasonal adjustment" is the main method of balancing the atmosphere.Pick a dry, dormant savannah, desert, or bramblebush and raise the temperature to wake it up for spring.Soon, the leaf buds rose up one after another.Then it rains again.Boom!All plants burst into foliage and flowers within four days.The awakened biome voraciously absorbs carbon dioxide.Once this ecological community is awakened, old branches can be pruned to promote new branches, consume carbon dioxide, and keep it active during the originally dormant time.As Leigh wrote in the late fall of his first year, "Winter days are getting shorter and we have to be prepared for less light. Today we trimmed the northern edge of the rainforest to encourage rapid growth - a day-to-day atmospheric management." These people manage the atmosphere through the "CO2 valve".Sometimes they do it the other way around: To fill the air with carbon dioxide, the biospherians drag out the hay they've mowed earlier, lay it out on the ground, and moisten it.The bacteria release carbon dioxide as they break them down. Leigh called the intervention of biospherians in the atmosphere a "molecular economy."As they regulate the atmosphere, they can “safely store carbon in our accounts and then withdraw it next year when the summers get longer and the plants need it.” Those basements act as carbon banks. , and the pruned branches are piled there and dried.This carbon is loaned out when needed, mostly with water.The water in Bio2 is rushing from place to place, much like the federal government spends to stimulate regional economies.Put water on the desert, and the carbon dioxide level decreases; pour water on the dry grass mat, and the carbon dioxide level increases.On Earth, our carbon bank is the oil beneath the Arabian desert, but all we do is consume it. Biosphere 2 compressed a long geological time into a few years.The biospherians' fiddling with the "geological" regulation of carbon storage and release is precisely in the hope of making rough adjustments to the atmosphere.They fiddled with the ocean, lowered its temperature, adjusted the backflow of saline permeate, slightly changed its pH, and they extrapolated about a thousand other variables at the same time."It's the thousands of variables that make the Bio2 system so challenging and eccentric," Leigh said. "Most of us were taught not to think about even two variables at the same time." Hopefully, with some luck, the initial wild shocks of the atmosphere and oceans will be tempered by some well-chosen major moves in the first year.They will act as training wheels until the system can maintain its balance throughout the year depending only on the sun, the seasons, and the natural movements of plants and animals.At that point, the system "pops out". "Emerging" is saltwater aquarium lingo to describe the sudden stabilization of a new tank after a tortuous, long period of instability.Like Bio2, saltwater aquariums are delicate closed systems that rely on invisible microbes to dispose of waste from larger plants and animals.As Gomez, Folsom, and Pimm discovered in their small world, it can take up to 60 days for a stable microbial community to take shape.In an aquarium, it takes months for various bacteria to build a food web and settle themselves in the gravel of a new aquarium.As more life species are slowly added to this immature fish tank, the aquatic environment can easily fall into a vicious circle.Excessive amounts of certain components (ammonia, for example) will kill some organisms, and the decay of organisms will release more ammonia, kill more organisms, and quickly cause the collapse of the entire community.In order for the aquarium to move smoothly through this extremely sensitive period of imbalance, aquarists gently stimulate this ecology with appropriate water changes, addition of chemicals, installation of filters, and introduction of bacteria from otherwise stable aquariums. system.After 6 weeks or so of microbial accommodation—during which time the nascent colony teetered on the edge of chaos—suddenly, the system “popped” overnight, and the ammonia quickly returned to zero.It can now run for a long time.Once the system "emerges", it is more self-reliant and self-stable, and it no longer needs the human support required when it was started. Interestingly, in the two days before and after the "emergence" of a closed system, the environment in which it is located hardly changes.In addition to being able to do some "nanny" work, often all you can do is wait.Wait for it to develop, mature, grow, develop.Marine fish farming enthusiasts suggest: "Don't worry, don't rush to gestate the system when it is self-organizing. The most important thing you can give it is time." Two years later, Bio2 is still green and maturing.It goes through wild initial oscillations requiring "human" care to settle it down.It hasn't "popped out" yet.It may be years (or even decades) before it "pops"—if it does and does.That's the purpose of this experiment. We haven't really noticed yet, but we may find that all complex coevolutionary systems need to "pop out".Ecosystem restorers such as Packard, who restored the prairie, and Wingate, who restored Nansatchie, seem to have discovered that large systems can be reorganized by gradually increasing complexity; will easily tend to regress, as if the system is "sucked" by the cohesion brought about by the new complexity.Human organizations, such as teams and companies, also show the characteristic of "emerging".A few small nudges—the right new managers on board, clever new tools—could instantly organize 35 hardworking and capable people into a creative organism that was far ahead of its time.Machines and mechanical systems will also "pop" as long as we exploit enough complexity and flexibility to make them.