Читать книгу The Anthropocene - Christian Schwägerl - Страница 7

WHETHER YOU TAKE A WALK in the hills around your town or along the coast or by a river, you will encounter the results of geological forces that have been at work for millions of years. Magma that once was deep inside the earth has formed rocks and moved tectonic plates. Water has shaped shorelines and carved out deep valleys. Wind erosion has flattened mountains and created massive deposits of soil and sand.

The exact spot on the earth’s surface that now lies beneath the city of Berlin, the German capital, where I live, was once near the earth’s southern pole some 500 million years ago. Tectonic forces moved it north over that immense period of time.¹¹ Only tens of thousands of years ago, the area was covered with huge glaciers; the weight and the power of their melting water created today’s landscape. Without much effort, one can also observe more recent changes due to geophysical forces. I only have to walk 500 yards from home to reach Heidelberger Platz, from where a wide boulevard runs toward the stores and cafés in the center of West Berlin. The difference in slope between one end of the street and the other is so slight that, in this otherwise flat city, most cyclists and motorists barely notice it. But there is a big story behind this slight slope. It was once the bank of a gigantic river that flowed here at the end of the last Ice Age, 12,500 years ago. This Urstrom (glacial river) was filled with icy water several hundred meters high, to the north of what is now Berlin, before the great thaws set in and the glaciers gradually melted away.

When I cycle down this slope, I hear cars thundering past. I try to imagine the thundering mass of water that used to rush past, which formed the landscape of sand and stone on which the city of Berlin arose in the thirteenth century. The opposite bank of this primeval river is almost six miles away in Prenzlauer Berg, one of Berlin’s hip new districts. The river must have been gigantic and would make today’s River Spree, which runs through the political and cultural center of Berlin, near the Brandenburg Gate, seem like a mere creek.

When you contemplate Earth’s history—not just by rattling off things you learned at school but by touching stones or letting sand run through your hands or swimming in a river—even a brief encounter can turn into a fantastic adventure. For me, the excitement is even greater when I become aware of the workings of earlier life forms. Many inland hills found on continents are in fact the remains of ancient coral reefs. Many mountain ranges far from the sea are composed of the calcareous skeletons of earlier marine organisms. Thick deposits of coal and oil, which have provided the fuel for industrial prosperity, are the residues of earlier life forms. Here in Berlin, there is a lot of bog and marshland. When you go hiking where fauna and flora are scant, you sometimes feel as if you are in a Zen garden where lots of decaying moss is underfoot; if it were left undisturbed, these mosses would eventually form coal. In bogs like these you can witness geology at work. You can see how the stones here and the earth’s crust are connected to life itself.

Earth’s surface, as we know it today, has been transformed by a select group of organisms which I refer to as “The Club of Revolutionaries.” These are the life forms that did not die out unceremoniously after a mere couple of million years. These are the species that did not just surrender their molecules to the great recycling process called evolution, to be absorbed by other life forms.

The Club of Revolutionaries is comprised of species that have caused lasting change and have created new structures, just as fire, water and wind have done. We still encounter them, eons after their biological demise, in the form of bizarre limestone sculptures, or as pitch-black coal seams, deep below the ocean.

The oldest—and from our point of view, most essential “revolutionary” is the one that has made possible today’s earth, with all its trees and flowering plants, birds and mammals. This revolutionary is a tiny microorganism that has evolved over three billion years. It used to be called blue-green algae but this label was discarded once scientists realized they weren’t dealing with algae at all but rather with bacteria. Since then, such life forms have been referred to as cyanobacteria. They paved the way for life to use the sun’s energy and to spread from sea to land across the whole surface of the planet.

Before cyanobacteria entered the scene, a young earth, amassed from matter orbiting the sun, had already been through some dramatic changes. It had been hit by another celestial body, a space traveler roughly the size of Mars.¹² Theia, as it’s now called, created such impact that the moon was ejected from the earth’s mass. As a result, the planet’s axis of rotation became tilted, leading to tides and seasons. The fiery interior of the earth still holds the heat from that impact—so, in a sense, we don’t live on one planet, but actually two. After Earth’s and Theia’s matter had merged, a core formed, composed mostly of iron, and a new magnetic field developed, shielding the planet’s surface from harmful radiation from space. Next, a primordial atmosphere began to coalesce, consisting of toxic gases that would certainly be fatal to contemporary organisms. And then, approximately 3.7 to 4 billion years ago, a second “Big Bang” occurred, this one biological. Simple molecules morphed into cells that could replicate themselves. The earth now began to sustain life. In continuous cycles of mutation and replication, adaptation and extinction, these first life forms, now known as archaebacteria, evolved. But they were soon to be confronted with an early resource crisis. The chemical energy they needed for survival became increasingly scarce in their primeval world.

It was then that cyanobacteria entered the scene. Their altered metabolism proved to be superior in one essential respect: whereas archaebacteria were dependent on the earth’s chemical energy, cyanobacteria were able to tap into the sun’s constant flow of energy. They developed molecular networks and metabolic pathways—the ability to convert energy from light and heat to enable small cell photosynthesis. Thus life’s first resource crisis was solved to its advantage, yet if viewed from archaebacteria’s perspective, it also created the first environmental disaster. Photosynthesis generated large quantities of oxygen. This element had already been present in the earth’s atmosphere in its poisonous molecular form, O₂, but only in limited quantity as a trace element.

Now, cyanobacteria were pumping large amounts of O₂ into the atmosphere. Over the course of millions of years, the concentration of this gas grew, with far-reaching consequences. For archaebacteria, oxygen was poisonous, so they retreated to very remote locations, like deep-sea vents. Cyanobacteria, on the other hand, fared so well in this new oxygenated world that they multiplied, eventually spreading across the oceans and coastal regions, to form extensive mats and vast nodular colonies.

Thus, cyanobacteria became founders of “The Club of Revolutionaries,” They released so much oxygen into the atmosphere that around 2.6 billion years ago, dissolved iron in the seas began to oxidize and settle to the bottom. Vast deposits of iron ore were formed, used today in the construction of buildings, complex machines and electronic equipment.

Once the oceans were saturated with oxygen, surplus gas escaped into the atmosphere, and the next revolution began. High up in the sky, ultraviolet radiation transformed some of this copious O₂ into O₃. (O₂, which contains two atoms of oxygen, is much more stable than O₃, with its three oxygen atoms.) This transformation created the ozone layer, which has intercepted the most aggressive radiations from the sun. (That is, until a life form called Thomas Midgley began tinkering with artificial chemical compounds). It was only due to this protective layer around the “sea of air”—as Alexander von Humboldt called the atmosphere—that new, more complex life forms could evolve. Approximately 420 million years ago life, in the form of plants, amphibians, reptiles and mammals, spread over the land.

Cyanobacteria not only provided these more complex life forms with the oxygen necessary to digest food effectively, they also passed on the molecular technology to produce it. According to a widely supported hypothesis, all multicellular plants came into existence by absorbing cyanobacteria and using them as interior “solar panels” to generate photosynthesis.¹³ Cyanobacteria thus became a component of each of the quarter million plant species known today, from cacti and dandelions to Sequoia trees. They have even stored a ration of their own genetic material. For these partners, it was a win-win situation. Cyanobacteria’s distant descendants are found everywhere plants grow, making the forest green. In addition, free-roaming cyanobacteria are still around. Two thousand contemporary species have been recorded to date. In the 1980s, American marine biologists Sallie W. Chisholm and Robert J. Olson, along with other collaborators, discovered a life form that had been previously overlooked. The organism was tiny but once it was detected, further research revealed that the cyanobacteria Prochlorococcus marinus was one of the most common organisms on earth and was probably one of the most widely spread types of picoplankton in the world.¹⁴

Most people today are unaware of cyanobacteria except in unpleasant circumstances. If they are present in large quantities, due to fertilizer run-off and warm weather, they can produce substances that irritate human skin. But in places like Australia, cyanobacteria can also be admired: For millions of years, they have formed large colonies where their excretions produce stone-like structures, called stromatolites.

No matter where you are or what you do, when you breathe to stay alive or enjoy time outside, when you eat vegetables or buy something made of iron or steel, you are inextricably linked to these revolutionaries.

This extraordinary feat surely merits having a memorial erected in every modern city, in honor of the founders of the Club of Revolutionaries: “To the creators of the oxygen atmosphere, our planet’s protective shield, the plant world and iron deposits: In gratitude, humanity.”

So far, that hasn’t happened. But in the step-by-step process of science, humanity is at least starting to discover how deeply connected we are, not only to our primate ancestors but also to a whole set of life forms that have made and continue to make earth livable. By doing research, humans have learned how bacteria, plants and animals have sustained life on earth and they have even begun doing experiments that attempt to recreate the conditions by which earth has stayed habitable.

One of the first to do this kind of research was Joseph Priestley, a British chemist, theologian, philosopher and physicist. In 1772, he founded the discipline of earth modeling. Today, earth modelers have the advantage of gleaning reams of data from satellites and supercomputers. Priestley, who was interested in oxygen and who is regarded as one of its discoverers, worked with simpler technology. He trapped mice under a bell jar and watched what happened. After disposing of the inevitably dead animals several times, he was surprised when he observed that mice survived if he included a green, living plant, thus creating a tiny, enclosed ecosystem.

Priestly wrote the first ever description of photosynthesis, describing how animals and plants interact, in his inimitable prose: “These proofs of a partial restoration of air by plants in a state of vegetation, though in a confined and unnatural situation, cannot but render it highly probable, that the injury which is continually done to the atmosphere by the respiration of such a number of animals, and the putrefaction of such masses by both vegetable and animal matter, is, in part at least, repaired by the vegetable creation.”¹⁵

With his bell jar, Priestley inspired a whole new research discipline: ecology, and later biospherics, the study of artificial, enclosed ecosystems. In 1875, Austrian geologist Eduard Suess created the term “biosphere” to describe the space used by living organisms. A few decades later, the Russian geologist Vladimir Vernadsky expanded this concept when he realized that the biosphere is not only inhabited by living organisms but has also been shaped by them. Vernadsky demonstrated how humans are existentially a part of the biosphere.

When both the USA and the USSR were in a race to reach the moon and conquer the vastness of space, Russian scientist Yevgeny Shepelev confined himself in the smallest possible artificial ecosystem, assigning himself the role of Joseph Priestley’s mice.

In 1962, he climbed into a small, airtight metal container at the Institute of Biomedical Problems in Moscow. When he sealed the door behind him, he was not alone: he shared the cramped space with forty-five liters of green algae, of the genus Chlorella. His plan was for the algae to supply him with the oxygen he needed to survive. This forty-two-year-old Russian was the first person to make himself completely dependent on a bucket of plants.¹⁶

Shepelev grew up with eight siblings in impoverished circumstances. He discovered his love of science very early in life and managed to be accepted into the scientific youth club at the Moscow Zoological Gardens. He then studied medicine and devoted himself to a broader subject: how life could survive in outer space. He wanted his containers to show that cities of the future could be built and maintained, on other planets. Thus, the Soviet Union would colonize outer space before the capitalist West.

Shepelev’s first experiment lasted a mere twenty-four hours. When a colleague opened the door of the container, he complained of being hit by a rotting smell. Its occupant was dazed and confused, his thought processes befuddled by his own exhaled gases. Yet, Shepelev had actually managed to live off the oxygen produced by his algae.¹⁷

In the Siberian city of Krasnoyarsk, other scientists were undertaking similar, strictly confidential research. In 1972 three scientists managed to survive for half a year in BIOS-3, an artificial ecosystem, without external supplies of water and oxygen. By the end of the 1980s, Russian scientists succeeded in producing three quarters of the food they needed, in “closed” systems. Since a diet consisting entirely of algae made them feel bad tempered, they started growing cucumbers, tomatoes, potatoes, peas and other container plants, and even created a new type of soil that was dubbed “soil-similar substrate.”

In time, the Russians became more daring. When the political climate in the Soviet Union began to change in the mid-1980s, they even started doing tests to measure environmental problems that, by definition, did not exist in a “socialist” society, even though everyday Soviet life was full of them. The scientists pumped pollutants into containers to investigate the effects. “The ability to buffer these kinds of substances and transform them is limited,” stated a terse summary in one report. What was meant by this was clear: ecosystems can handle stress for a long time but under continual stress they will eventually collapse.¹⁸

While the Russian experiments were being carried out in secrecy, a group of scientists and idealists in the USA, meanwhile, were working on a significantly more complicated artificial ecosystem. In 1991, with great fanfare, Biosphere 2 was inaugurated by John P. Allen, a maverick with a background in mining and metallurgy, who had a strong personal vision that Biosphere 1, planet Earth, was in big trouble. Allen once held the rights to a coal seam worth a fortune, but according to him, the expected course of his life completely changed after a transformative experience with the psychotropic plant peyote which made him directly aware of the biosphere.¹⁹ Consequently, in the late 1980s, he formed an unlikely alliance between ecologically-minded friends and associates, American scientists and the Texan venture capitalist Edward Bass, in order to build the largest self-contained ecosystem in the world.

Between 1991 and 1994, two groups of “biospherians” lived in an enormous, sealed glass, cathedral-like structure, in the Arizona desert, which had taken four years to build. The first crew of eight spent two years inside. Biosphere 2 was a manifestation of research, environmental education and media hype. Like Yevgeny Shepelev, both John Allen and Edward Bass were interested in future settlements in space. Biosphere 2 may have looked like a study of how humans can live in an artificial environment but it turned out to be the complete opposite.²⁰

The Biosphere 2 project generated a great deal of interest worldwide. For an admission fee, visitors were even allowed into Biosphere 2, itself. The grandiose white structure housed a man-made rainforest, an ocean, a coral reef, a mangrove swamp, a desert and a savannah, all in miniature forms. Two and a half thousand square meters of agricultural land were set aside to produce food for the biospherians and a diverse selection of animals, ranging from bees for pollination to pygmy goats, were also included.

The first crew of eight biospherians moved into the enormous complex in 1991. Their aim was to live in the synthetic ecosystem for at least two years or for as long as possible, researching and observing how conditions for life changed over time. Serious problems arose, early on. The concentration of oxygen in the air dropped continuously during the first year and a half, from nearly 21 percent atmosphere, as in Biosphere 1, to 14.5 percent, similar to mountain air at four thousand meters above sea level. It took a while to ascertain the cause: Bacteria in the virgin soil, was consuming oxygen in the air while at the same time chemically active concrete walls were absorbing oxygen and producing calcium carbonate. Fatigue set in among the biospherians, so measured amounts of liquid oxygen were pumped in. The food supply was erratic, too. Pollinating insects died off while ants and cockroaches thrived. The harvest produced a smaller yield than expected, partly because of two consecutive years of the El Niño weather phenomenon, so reserve food stocks had to be used. The first mission ended after the prescribed two years setting world records (by far) for duration in enclosed human life support experiments. A second crew entered Biosphere 2 in March 1994 but the mission was terminated prematurely as a result of disputes between Allen and his design/management team, with his partner, Ed Bass and his team. After the partnership dissolved, the goals of the project shifted away from human enclosure experiments.²¹

While many in the media suggested it was a failure, Biosphere 2 had made an incredible contribution, not least with the many research and scientific papers it has produced and indeed is still producing.²² It is because of the difficulties the project encountered that it became even more significant.

Each problem with living in an artificial ecosystem symbolizes the present situation of humanity. The scores of deriders who made fun of the bionauts in Russia and the biospherians in the Arizona desert must have forgotten how much harm people in the real world cause to the ozone layer, or to precious animal species that could become extinct before our very eyes. People forget what causes a shortage of food supplies for nearly a billion people or how we risk making the earth’s climate very uncomfortable for ourselves.

The Russian and American projects yielded an essential insight: the earth is constantly providing us with a multitude of services and processes that have evolved over the course of hundreds of millions of years, thanks to the work of early earth “revolutionaries.” If you want to re-create these services in the form of huge artificial ecosystems that can sustain hundreds of millions of people, the costs will clearly rocket into infinity. Even 150 million dollars was not sufficient for the Arizona experiment to sustain eight people in a 1.2–hectare artificial ecosystem. These biospheric projects therefore showed that nature sustains human civilization and the world economy.

Today, the University of Arizona owns and directs research at the Biosphere 2 facility. It would be good if there or elsewhere, bionauts or biospherians would again move inside enclosed systems to determine if humans can survive in strictly confined spaces.

It is telling how much people appreciate the oxygen created by cyanobacteria or simple plants or fruits when they are cut off from nature. In November 2013, Japanese astronaut Koichi Wakata tweeted an image from the International Space Station. It showed a tomato in a state of weightlessness, while the earth could be seen in the background. “One fresh tomato for dinner makes us happy in space. It came up with us on Soyuz TMA-11M, two weeks ago,” read his text about the red marvel, seemingly appearing in front of the Blue Marble.²³

In the Anthropocene, the earth itself becomes one giant biospheric experiment, but without any emergency exits or windows to let in additional fresh air. So, when you take your next walk outside, look closely, not only at the results of what wind, fire and water have carved out and what other organisms have left behind, but also examine the results of thousands of years of human activity. These cumulative actions stack up to look like a new geological epoch that puts us on a par with the cyanobacteria and other earth-transforming species: Welcome to “The Club of Revolutionaries.”

^11. Documentation for Berlin’s geographical spot having traveled from the South polar region to its current location may be found in several sources: Stampfli, Gérard M., Jürgen F. von Raumer & Gilles D. Borel, “Paleozoic evolution of pre-Variscan terranes: From Gondwana to the Variscan collision,” Geological Society of America Special Paper 364, 2002 and in Cocks, L.R.M. and T.H. Torsvik, “European geography in a global context from the Vendian to the end of the Palaeozoic,” Geological Society, London, Special publications, 2006.

^12. Alex Halliday, “The Origin of the Moon,” Science, vol. 338, no. 6110 (2012): 1040–1041; Matija Cuk and Sarah Stewart, “Making the Moon from a Fast-Spinning Earth: A Giant Impact Followed by Resonant Despinning,” Science, vol. 338, no. 6110 (2012): 1047–1052.

^13. See seminal article of Lynn Sagan, “On the origin of mitosing cells,” Journal of Theoretical Biology, vol.14 no.3, March 1967.

^14. Sallie W. Chisholm et al., “A novel free-living prochlorophyte abundant in the oceanic euphotic zone”, Nature, 1988, vol. 334 (1988): 340–343 and F. Partensky et al. “Prochlorococcus, a marine photosynthetic prokaryote of global significance”, Microbiology and Molecular Biology Reviews vol. 63 (1999): 106–27.

^15. Joseph Priestley, “Observations on Different Kinds of Air,” Philosophical Transactions of the Royal Society, 62, (1772): 147–264, quoted from Malcolm Dick (ed.), Joseph Priestley and Birmingham, Brewin Books (2005).

^16. The biographical details were obtained from the Institute from Biomedical Problems in Moscow in a personal communication, April 2010.

^17. Personal communication with Prof. A.G. Degermendzhi, Director of the Institute of Biophysics and Prof. A.A Tikhomirov, Director of the International Center for Closed Ecosystems in Krasnoyarsk, April 2010.

^18. Frank B. Salisbury et al., “Bios-3: Siberian Experiments in Bioregenerative Life Support,” BioScience, vol. 47 (1997): 575–585.

^19. John Allen has written an autobiography: John Allen, Me and the Biospheres, Synergetic Press, Santa Fe, NM, 2009.

^20. John Allen et al., “The Legacy of Biosphere 2 for the study of Biospherics and closed ecological systems,” Advances in Space Research, vol. 31, no. 7 (2003):1629–1639.

^21. Personal communication with John Allen.

^22. Most of the key published papers are available at www.globalecotechnics.com. Elsevier special edition: Biosphere 2 Research Past and Present, eds.. B.D.V. Marino, H.T. Odum, Ecological Engineering Special Issue, Vol. 13, Nos. 1-4, Elsevier Science, 1999.

^23. http://wordlesstech.com/2013/11/26/tomato-space/