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How Does Matter Flow in the Biosphere?
Matter flows within the biosphere through recycling by organisms and biochemical cycles. Organisms merely transform matter and do not deplete it, so it is possible for matter to cycle in various biological systems. Examples of matter flow within the biosphere include the water cycle and nutrient cycles.
The water cycle contributes to matter flow in the biosphere through its passing between organisms and the environment. When water enters the roots of a plant, it can either be used by the plant or get passed to another organism through consumption. Transpiration occurs when water evaporates from the leaves of a plant and re-enters the atmosphere, where it eventually condenses into rain and falls back to the earth, continuing the cycle.
The nutrient cycle includes other elements and compounds necessary for life and subsequently exchanged by various organisms. Examples are the nitrogen cycle, the carbon cycle and the phosphorus cycle. The nitrogen cycle occurs when specific bacteria transform atmospheric nitrogen into a form usable by other organisms, such as when nitrogen gas is converted into ammonia through nitrogen fixation. These bacteria can also transform nitrogen into nitrates or nitrites, which can then form the basis of proteins. Consumers that eat the producers of protein then transfer this nutrient throughout other layers of the biosphere. Decomposers transform dead organic material back into ammonia, where it is returned to the soil as the cycle continues.
Credit: NOAA National Weather Service
Water is practically everywhere on Earth. Viewed from space, one of the most striking features of our home planet is the water, in both liquid and frozen forms, that covers approximately 75% of the Earth’s surface. Geologic evidence suggests that large amounts of water have likely flowed on Earth for the past 3.8 billion years—most of its existence. Believed to have initially arrived on Earth’s surface through the emissions of ancient volcanoes, water is a vital substance that sets the Earth apart from the rest of the planets in our solar system. In particular, water appears to be a necessary ingredient for the development and nourishment of life.
Water is the only common substance that can exist naturally as a gas, liquid, or solid at the relatively small range of temperatures and pressures found on the Earth’s surface. Sometimes, all three states are even present in the same time and place, such as this wintertime eruption of a geyser in Yellowstone National Park.
In all, the Earth’s water content is about 1.39 billion cubic kilometers (331 million cubic miles), with the bulk of it, about 96.5%, being in the global oceans. As for the rest, approximately 1.7% is stored in the polar icecaps, glaciers, and permanent snow, and another 1.7% is stored in groundwater, lakes, rivers, streams, and soil. Only a thousandth of 1% of the water on Earth exists as water vapor in the atmosphere.
For human needs, the amount of freshwater on Earth—for drinking and agriculture—is particularly important. Freshwater exists in lakes, rivers, groundwater, and frozen as snow and ice. Estimates of groundwater are particularly difficult to make, and they vary widely. (The value in the above table is near the high end of the range.) Groundwater may constitute anywhere from approximately 22 to 30% of fresh water, with ice (including ice caps, glaciers, permanent snow, ground ice, and permafrost) accounting for most of the remaining 78 to 70%.
Groundwater is found in two broadly defined layers of the soil, the “zone of aeration,” where gaps in the soil are filled with both air and water, and, further down, the “zone of saturation,” where the gaps are completely filled with water. The boundary between these two zones is known as the water table, which rises or falls as the amount of groundwater changes.
The amount of water in the atmosphere at any moment in time is only 12,900 cubic kilometers, a minute fraction of Earth’s total water supply: if it were to completely rain out, atmospheric moisture would cover the Earth’s surface to a depth of only 2.5 centimeters. However, far more water—in fact, some 495,000 cubic kilometers of it—are cycled through the Atmosphere every year. It is as if the entire amount of water in the air were removed and replenished nearly 40 times a year.
Despite its small amount, this water vapor has a huge influence on the planet. Water vapor is a powerful greenhouse gas, and it is a major driver of the Earth’s weather and climate as it travels around the globe, transporting latent heat with it. Latent heat is heat obtained by water molecules as they transition from liquid or solid to vapor the heat is released when the molecules condense from vapor back to liquid or solid form, creating cloud droplets and various forms of precipitation.
Water vapor—and with it energy—is carried around the globe by weather systems. This satellite image shows the distribution of water vapor over Africa and the Atlantic Ocean. White areas have high concentrations of water vapor, while dark regions are relatively dry. The brightest white areas are towering thunderclouds.
The water, or hydrologic, cycle describes the journey of water as water molecules make their way from the Earth’s surface to the Atmosphere and back again, in some cases to below the surface. This gigantic system, powered by energy from the Sun, is a continuous exchange of moisture between the oceans, the atmosphere, and the land.
Water molecules can take an immense variety of routes and branching trails that lead them again and again through the three phases of ice, liquid water, and water vapor. For instance, the water molecules that once fell 100 years ago as rain on your great- grandparents’ farmhouse in Iowa might now be falling as snow on your driveway in California. Water at the bottom of Lake Superior may eventually rise into the atmosphere and fall as rain in Massachusetts. Runoff from the Massachusetts rain may drain into the Atlantic Ocean and circulate northeastward toward Iceland, destined to become part of a floe of sea ice, or, after evaporation to the atmosphere and precipitation as snow, part of a glacier.
Water continually evaporates, condenses, and precipitates, and on a global basis, evaporation approximately equals precipitation. Because of this equality, the total amount of water vapor in the atmosphere remains approximately the same over time. However, over the continents, precipitation routinely exceeds evaporation, and conversely, over the oceans, evaporation exceeds precipitation.
In the case of the oceans, the continual excess of evaporation versus precipitation would eventually leave the oceans empty if they were not being replenished by additional means. Not only are they being replenished, largely through runoff from the land areas, but over the past 100 years, they have been over-replenished: sea level around the globe has risen approximately 17 centimeters over the course of the twentieth century. The main source of this excess runoff from land contributing to sea level rise is the melting of land ice, particularly in Greenland and Antarctica.
Sea level has been rising over the past century, partly due to thermal expansion of the ocean as it warms, and partly due to the melting of glaciers and ice caps. (Graph ©2010 Australian Commonwealth Scientific and Research Organization.)
Sea level has risen both because of warming of the oceans, causing water to expand and increase in volume, and because more water has been entering the ocean than the amount leaving it through evaporation or other means. A primary cause for increased mass of water entering the ocean is the calving or melting of land ice (ice sheets and glaciers). Sea ice is already in the ocean, so increases or decreases in the annual amount of sea ice do not significantly affect sea level.
Blackfoot (left) and Jackson (right) glaciers, both in the mountains of Glacier National Park, were joined along their margins in 1914, but have since retreated into separate alpine cirques. The melting of glacial ice is a major contributor to sea level rise. [Photographs by E. B. Stebinger, Glacier National Park archives (1911), and Lisa McKeon, USGS (2009).]
Throughout the hydrologic cycle, there are many paths that a water molecule might follow. Water at the bottom of Lake Superior may eventually rise into the atmosphere and fall as rain in Massachusetts. Runoff from the Massachusetts rain may drain into the Atlantic Ocean and circulate northeastward toward Iceland, destined to become part of a floe of sea ice, or, after evaporation to the atmosphere and precipitation as snow, part of a glacier.
Water molecules can take an immense variety of routes and branching trails that lead them again and again through the three phases of ice, liquid water, and water vapor. For instance, the water molecules that once fell 100 years ago as rain on your great- grandparents’ farmhouse in Iowa might now be falling as snow on your driveway in California.
Evaporation, Transpiration, Sublimation
Together, evaporation, transpiration, and sublimation, plus volcanic emissions, account for almost all the water vapor in the Atmosphere that isn’t inserted through human activities. Studies show that evaporation—the process by which water changes from a liquid to a gas—from oceans, seas, and other bodies of water (lakes, rivers, streams) provides nearly 90% of the moisture in our atmosphere. Most of the remaining 10% found in the atmosphere is released by plants through transpiration where plants take in water through their roots, then release it through small pores on the underside of their leaves. For example, a cornfield 1 acre in size can transpire as much as 4,000 gallons of water every day. In addition, a very small portion of water vapor enters the Atmosphere through sublimation, the process by which water changes directly from a solid (ice or snow) to a gas. The gradual shrinking of snow banks in cases when the temperature remains below freezing results from sublimation.
Condensation & Precipitation
After the water enters the lower atmosphere, rising air currents carry it upward, often high into the atmosphere, where the rising air cools. In cooled air, water vapor is more likely to condense from a gas to a liquid to form cloud droplets. Cloud droplets can grow and produce precipitation (including rain, snow, sleet, freezing rain, and hail), which is the primary mechanism for transporting water from the atmosphere back to the Earth’s surface.
When precipitation falls over the land surface, it follows various routes in its subsequent paths. Some of it evaporates, returning to the atmosphere some seeps into the ground as soil moisture or groundwater and some runs off into rivers and streams. Almost all of the water eventually flows into the oceans or other bodies of water, where the cycle continues. At different stages of the cycle, some of the water is intercepted by humans or other life forms for drinking, washing, irrigating, and a large variety of other uses.
Sea Level Rise
Sea level has been rising over the past century, partly due to thermal expansion of the ocean as it warms, causing water to expand and increase in volume, and partly due to the melting of glaciers and ice caps because more water has been entering the ocean than the amount leaving it through evaporation or other means. (Graph ©2010 Australian Commonwealth Scientific and Research Organization.)
Snow and Ice Melt
A primary cause for increased mass of water entering the ocean is the calving or melting of land ice (ice sheets and glaciers). Sea ice is already in the ocean, so increases or decreases in the annual amount of sea ice do not significantly affect sea level.
Credit: NASA Earth Observatory
rhythmic repetition of biological phenomena in associations of organisms (populations, biocenoses), which serves as an adaptation to cyclic changes in their conditions of existence. Biological cycles are included in the more general concept of biological rhythms, which includes all rhythmically repeated biological phenomena. Biological cycles may be daily, seasonal (annual), or at intervals of many years.
Twenty-four-hour biological cycles are expressed in regular fluctuations in the physiological phenomena and behavior of animals during the course of a 24-hour day. At their base lie automatic mechanisms which are corrected by the effects of external factors: 24-hour variations in illumination, temperature, moisture, and so on.
At the base of seasonal biological cycles lie those metabolic changes which in animals are regulated by hormones. In various seasons the condition and behavior of organisms within a population or a biocenosis change: accumulation or consumption of reserve substances may occur shedding of outer layers (molting), reproduction, animal migration, hibernation, and other seasonal phenomena begin or end. Being to a considerable degree automatized, these phenomena are corrected by external influences (weather conditions, food reserves, and so on).
Biological cycles lasting many years are conditioned by cyclic variations of climate and other conditions of existence (in connection with changes in solar activity and other cosmic and planetary factors). Such biological cycles occur in populations and biocenoses and are expressed in fluctuations in reproduction and the numbers of certain species, in resettlement of populations in new places, or in the extinction of parts of populations. These phenomena are the end result of cyclic changes in populations and biocenoses and of fluctuations in their conditions of existence, mainly climate.
SPRING 2022 CORE-UA 305 001, Life Science: Human Origins
Prof. TBA (Anthropology)
This course provides a comprehensive introduction to the field of biological anthropology and explores the evolutionary history of our lineage. Topics include but are not limited to human and non-human primate genetics, behavior, osteology, paleoanthropology, bioarchaeology, and forensics. Particular emphases are placed on modern human biological variation and the human fossil record. In doing so, we will reconstruct the behavior—locomotor, social, sexual, and cultural—of our ancestors and close relatives using modern analogs including modern humans, our closest living relatives the great apes, and other primates and non-primate animals. This course begins with a review of cellular and molecular biology and evolutionary theory in general, then establishes our place in nature and geological time, and ends with a detailed foray into modern human origins, including fossils, artifacts, and inferred cultural behaviors. Additionally, we will explore modern human variation, including discussions of topics such as race, genetics, and sexuality.
SPRING 2022 CORE-UA 306, Life Science: Brain and Behavior
Prof. TBA (Neural Science)
The relationship of the brain to behavior, beginning with the basic elements that make up the nervous system and how electrical and chemical signals in the brain work to effect behavior. Using this foundation, we examine how the brain learns and how it creates new behaviors, together with the brain mechanisms that are involved in sensory experience, movement, hunger and thirst, sexual behaviors, the experience of emotions, perception and cognition, memory and the brain's plasticity. Other key topics include whether certain behavioral disorders like schizophrenia and bipolar disorder can be accounted for by changes in the function of the brain, and how drugs can alter behavior and brain function.
Note: Handling of animals and animal brain tissue is required in some labs.
SPRING 2022 CORE-UA 310, Life Science: Molecules of Life
Prof. Jordan (College Core Curriculum) [Syllabus]
Our lives are increasingly influenced by the availability of new pharmaceuticals, ranging from drugs that lower cholesterol to those that influence behavior. We examine the chemistry and biology of biomolecules that make up the molecular machinery of the cell. Critical to the function of such biomolecules is their three-dimensional structure that endows them with a specific function. This information provides the scientific basis for understanding drug action and how new drugs are designed. Beginning with the principles of chemical bonding, molecular structure, and acid-base properties that govern the structure and function of biomolecules, we apply these principles to study the varieties of protein architecture and how proteins serve as enzymes to facilitate biochemical reactions. We conclude with a study of molecular genetics and how recent information from the Human Genome Project is stimulating new approaches to diagnosing disease and designing drug treatments.
Note: This is course is not available to students who have completed CORE-UA 210.
SPRING 2022 CORE-UA 311, Life Science: Lessons from the Biosphere
Prof. TBA (Biology)
Provides a foundation of knowledge about how Earth's biosphere works. This includes the biggest ideas and findings about biology on the global scale-the scale in which we live. Such knowledge is especially crucial today because we humans are perturbing so many systems within the biosphere. We explore four main topics: (1) Evolution of Life: How did life come to be what it is today? (2) Life's Diversity: What is life today on the global scale? (3) Cycles of Matter: How do life and the non-living environment interact? (4) The Human Guild: How are humans changing the biosphere and how might we consider our future within the biosphere? Laboratory experiments are complemented by an exploration at the American Museum of Natural History.
Examples of Biogeochemical Cycle
The Water Cycle
The biogeochemical cycle of water, or the hydrological cycle describes the way that water (Hydrogen Dioxide or H2O) is circulated and recycled throughout Earth’s systems.
All living organisms, without exception, need water to survive and grow, making it one of the most important substances on Earth. In complex organisms it is used to dissolve vitamins and mineral nutrients. It is then used to transport these substances, as well as hormones, antibodies, oxygen and other substances around and out of the body. It also aids in the enzymatic and chemical reactions required for metabolism, and it is used for temperature regulation.
On a geographical level, the biogeochemical cycle of water is responsible for weather patterns. The temperature, the amount, and the movement of water, have an effect all weather systems. As water in its various forms (vapor, liquid and ice) interacts with its surroundings, it alters the temperature and pressure of the atmosphere, creating wind, rain and currents, and is responsible for changing the structure of earth and rock through weathering.
Although there is no real beginning to the water cycle, 97% of the world’s water is stored within the oceans, so here is a logical place to start.
Of the ocean water, a very small proportion becomes frozen at it reaches the poles, and is stored as ice within glaciers.
Some of the surface water is heated by the sun, and evaporation takes place. In this process, the liquid water is converted into water vapor and is taken up in to the atmosphere. As the water rises, it cools and condensation occurs. This results in the water being stored within the atmosphere in the form of clouds.
As the clouds are moved around the earth’s atmosphere they collide and grow. Eventually the water droplets grow large enough so that they are heavy enough to fall as precipitation (rain) or as snow, depending on the environmental conditions.
Most of the snow that falls is either stored as ice caps, or melts to form streams and rivers.
Some of the water that makes it to the ground is affected by gravity and flows back in to the ocean via surface runoff. Furthermore some of this water joins with freshwater streams and rivers, which eventually lead to the oceans, or it may be stored within lakes and reservoirs. This freshwater can be consumed by animals, who cycle the water through their bodies.
Much of the water that fell as rain, soaks in to the ground through infiltration. Here it either infiltrates deep into the rock, and forms huge stores called aquifers or it remains relatively close to the surface as groundwater flow.
The groundwater is taken in by the roots of plants and is used for photosynthesis. The water is then released into the atmospheric through evapotranspiration or is consumed when the plants are eaten.
Some of the groundwater emerges from springs and surface water bodies, eventually making its way back to the ocean.
The Carbon Cycle
As a main component of biological compounds, carbon can be found in all living things, as well as many non-living things such as minerals, the atmosphere, the oceans and the interior of the earth.
Although carbon is an essential component for life, it is only due to a specific balance of atmospheric components and conditions that life, as we know it, is able to exist. Therefore, it is important that a balance between the amount of carbon stored in sinks and the amount that is emitted from various sources is maintained.
Although all biogeochemical cycles of carbon are linked, it is simpler to vizualise them using two systems.
Rapid Carbon Biogeochemical Cycles
In this cycle, inorganic carbon, which is present in the atmosphere as CO2, is captured by autotrophs. These are usually photosynthesizing organisms such as plants, bacteria and algae.
During photosynthesis, the carbon is converted into organic compounds such as glucose, which are stored within the bodies of these organisms. This carbon can be stored for many hundreds of years within the bodies of plants in areas such as tropical rainforests.
When the organic compounds are consumed by heterotrophs, they are passed through the food web, where they are broken down into useful substances using cellular respiration. Cellular respiration produces CO2, which is released back into the atmosphere.
The ocean is the second largest carbon sink. As well as dissolved inorganic carbon which is stored at depth, the surface layer holds large amounts of dissolved carbon that is rapidly exchanged with the atmosphere.
Long-term Carbon Biogeochemical Cycles
The long-term storage of carbon occurs over thousands or millions of years and is important for maintaining stable atmospheric carbon levels.
When an organism dies, the carbon stored within their body is broken down into CO2 and other organic substances by decomposers. While some of this carbon is released into the atmosphere, a large portion of it remains sequestered within the soil. Through this process, soils become major reservoirs for carbon storage.
The largest carbon sink is the lithosphere (the earth’s rocks). Much of the earth’s carbon was stored within rocks when the earth was formed, however, it is also continuously cycled through the biogeochemical cycle of the biosphere. Calcium carbonate (CaCO3), which makes up the shells of marine organisms, forms limestone when it collects at the bottom of the ocean. This is one of the world’s largest carbon reservoirs.
Fossil fuels also contain huge amounts of carbon these are formed from the remains of plants and animals that lived millions of years ago. Under specific conditions, the carbon within their bodies was pressurized and ‘cooked’ to form hydrocarbons. Today this is found in the form of crude oil, coal and natural gas.
Human Impacts on the Carbon Biogeochemical Cycle
Humans are having a drastic impact on the natural cycling of carbon in the atmosphere and in the oceans.
Fossil fuels, which have stored vast amounts of carbon for millions of years, are being burned at a rate that is too fast for it to be returned to carbon sinks. Instead it is being released into the atmosphere as carbon dioxide and methane (CO) which prevents heat from escaping the atmosphere, resulting in the greenhouse effect.
Additionally, among other disruptive practices, deforestation is releasing carbon stored within plant matter and is reducing the number of plants available to capture it – this is especially true in tropical rainforests and peat bogs.
The unnatural interference with this delicate biogeochemical cycle by humans could have severe consequences for our planet.
Carbon Cycle Examples
The carbon cycle consists of many parallel systems which can either absorb or release carbon. Together, these systems work to keep Earth’s carbon cycle – and subsequently its climate and biosphere – relatively stable. Below are some examples of parts of Earth’s ecosystems that can absorb carbon, turn carbon into living matter, or release carbon back into the atmosphere.
One major repository of carbon is the carbon dioxide in the Earth’s atmosphere. Carbon forms a stable, gaseous molecule in combination with two atoms of oxygen. In nature, this gas is released by volcanic activity, and by the respiration of animals who affix carbon molecules from the food they eat to molecules of oxygen before exhaling it.
Carbon dioxide can be removed from the atmosphere by plants, which take the atmospheric carbon and turn it into sugars, proteins, lipids, and other essential molecules for life. It can also be removed from the atmosphere by absorption into the ocean, whose water molecules can bond with carbon dioxide to form carbonic acid.
The Earth’s crust – called the “lithosphere” from the Greek word “litho” for “stone” and “sphere” for globe – can also release carbon dioxide into Earth’s atmosphere. This gas can be created by chemical reactions in the Earth’s crust and mantel.
Volcanic activity can result in natural releases of carbon dioxide. Some scientists believe that widespread volcanic activity may be to blame for the warming of the Earth that caused the Permian extinction.
While the Earth’s crust can add carbon to the atmosphere, it can also remove it. Movements of the Earth’s crust can bury carbon-containing chemicals such as dead plants and animals deep underground, where their carbon cannot escape back into the atmosphere. Over millions of years, these underground reservoirs of organic matter liquefy and become coal, oil, and gasoline. In recent years, humans have begun releasing much of this sequestered carbon back into the atmosphere by burning these materials to power cars, power plants, and other human equipment.
Among living things, some remove carbon from the atmosphere, while others release it back. The most noticeable participants in this system are plants and animals.
Plants remove carbon from the atmosphere. They don’t do this as a charitable act atmospheric carbon is actually the “food” which plants use to make sugars, proteins, lipids, and other essential molecules for life. Plants use the energy of sunlight, harvested through photosynthesis, to build these organic compounds out of carbon dioxide and other trace elements. Indeed, the term “photosynthesis” comes from the Greek words “photo” for “light” and “synthesis” for “to put together.”
In a gracefully balanced set of chemical reactions, animals eat plants (and other animals), and take these synthesized molecules apart again. Animals get their fuel from the chemical energy plants have stored in the bonds between carbon atoms and other atoms during photosynthesis. In order to do that, animal cells dissemble complex molecules such as sugars, fats, and proteins all the way down to single-carbon units – molecules of carbon dioxide, which are produced by reacting carbon-containing food molecules with oxygen from the air.
The Earth’s oceans have the ability to both absorb and release carbon dioxide. When carbon dioxide from the atmosphere comes into contact with ocean water, it can react with the water molecules to form carbonic acid – a dissolved liquid form of carbon.
When there is more carbonic acid in the ocean compared to carbon dioxide in the atmosphere, some carbonic acid may be released into the atmosphere as carbon dioxide. On the other hand, when there is more carbon dioxide in the atmosphere, more carbon dioxide will be converted to carbonic acid, and ocean acidity levels will rise.
Some scientists have raised concerns that acidity is rising in some parts of the ocean, possibly as a result of increased carbon dioxide in the atmosphere due to human activity. Although these changes in ocean acidity may sound small by human standards, many types of sea life depend on chemical reactions that need a highly specific acidity level to survive. In fact, ocean acidification is currently killing many coral reef communities.
Carbon Cycles and Energy Flow through Ecosystems and the Biosphere
In this analysis and discussion activity, students learn why the biosphere requires a continuous inflow of energy, but does not need an inflow of carbon atoms. Students analyze how the process of photosynthesis illustrates the general principles of conservation of matter and the second Law of Thermodynamics.
Then, students analyze how carbon cycles and energy flow through ecosystems result from photosynthesis, biosynthesis, cellular respiration, and the trophic relationships in food webs. Thus, students learn how important ecological phenomena result from processes at the molecular, cellular and organismal levels.
The Student Handout is available in the first two attached files and as a Google doc designed for use in distance learning and online instruction. The Teacher Notes, available in the last two attached files, provide instructional suggestions and background information and explain how this activity is aligned with the Next Generation Science Standards.
Carbon Cycle Poster
Working in groups, students can create simple illustrations of how carbon flows between the biosphere, hydrosphere, atmosphere and lithosphere. Use the provided materials to tell the story of how human activity can contribute to global climate change.
- illustrate the carbon flows that occur between the biosphere, hydrosphere, atmosphere and lithosphere.
- illustrate and explain how humans alter carbon flows between the four spheres
- identify human alterations of carbon flows that contribute to global climate change.
- poster or butcher paper
- construction paper in four different colors to represent the different spheres (we suggest blue to represent hydrosphere, green to represent biosphere, yellow to represent atmosphere, and brown to represent lithosphere)
- scotch tape
- colored pencils, crayons, or markers
- Carbon Flow Arrows
- Human Alteration Arrows
- Carbon Cycle Poster Human Alteration Cards
- Carbon Cycle Poster Human Alteration Answers
- Collect supplies, cutting poster paper for each group of four.
- Draw the color key on the board for the 4 spheres.
- Print out and cut arrows and alteration cards.
Discuss what the words “biosphere, lithosphere, hydrosphere, and atmosphere” mean. We suggest guiding students in dissecting the words: Bio means life, litho means rock, hydro means water, and atmos is Greek for vapor. Sphere refers to a part or parts of the planet.
- The biosphere is composed of the parts of the planet that contain life.
- The lithosphere is composed of the parts of the planet that contain rocks and sediments.
- The hydrosphere is composed of the parts of the planet with water
- The atmosphere is composed of the parts of the planet with vapor or gases.
Teach the carbon cycle. We suggest using the Carbon Cycle Role-Play activity, but a lecture format will work too.
- Break students up into groups of four and distribute poster paper to each. Explain that their task will be to work together to design a carbon cycle poster which illustrates how the carbon moves between the four different spheres.
- Have each group help cut out and label the spheres.
- Give each group four pieces of construction paper, each a different color. Referencing your color key, tell students that each piece of paper will represent one of the four spheres: biosphere, atmosphere, hydrosphere, and lithosphere.
- Have each student choose one piece of paper and cut a large circle from it. Then, have students write the the name of the sphere on their circle and draw something that represents that sphere (e.g., leaves, clouds, drops, mountains).
- Have each group create a diagram by taping the spheres and the arrows onto the poster in such a way as to explain how carbon flows through the four spheres.
- Give each group of students a set of 9 Carbon Flow Arrows, but don’t distribute the human alteration arrows yet. Tell students that these arrows show how carbon moves from one sphere to another.
- If needed, go over some of the vocabulary on the arrows with the students.
- Tell students that their task is to place the arrows between the appropriate spheres. Emphasize that the arrows should face the appropriate direction on their posters.
Teacher Tip: Check for understanding by glancing at posters as they work, and guide students as appropriate. Focus on having them explain their reasoning, referring to prior experience, such as with the Carbon Cycle Role-Play.
- After students have finished connecting their spheres with the arrows, bring everyone together as a class to compare their systems and explain their thinking. You can make a diagram on the board (see example) if it helps to clarify misunderstandings.
- Discuss how these posters model the system, and what ideas might be clear or missing from this diagram (e.g., carbon is sometimes a solid, liquid, or gas the quantity of carbon moved through each arrow is not expressed).
Assessment Boundary: If you are working towards Performance Expectations 5-LS2-1 or MS-LS2-3 or HS-LS2-5 regarding developing a model to describe the movement of matter among living and non-living parts of an ecosystem, remember that students are not expected to demonstrate understanding of molecular movement or describe the process using chemical reactions.
Assessment Boundary: If you are working towards Performance Expectations 5-ESS2-1 or MS-ESS2-1 or HS-ESS2-6 regarding developing a model to describe ways the geosphere, biosphere, hydrosphere, and/or atmosphere interact, remember that 5 th graders only need to explain the interactions of two systems at a time. The emphasis for middle school is on the geologic process of the rock cycle, and the emphasis in high school is on how biogeochemical cycles that include the cycling of carbon through the ocean, atmosphere, soil, and biosphere (including humans), provide the foundation for living organisms.
- Give each group a Human Alteration Card. Hand out the Human Alteration Arrow Sheets and tell students to cut out the arrow and to write their specific human alteration on the arrow.
- Tell students to place the human alteration arrow on their poster to reflect how the alteration would move carbon from sphere to sphere. Some of these are tricky, so tell students it is okay if they don’t know the answer for sure because you will go over it as a class.
- Have each group present their human alteration and how they think it impacts the carbon cycle to the rest of the class. Use the Human Alteration Answers to check student work and to guide the class in discussion.
- After each group presents, make sure to discuss how the initial impact of a human alteration to the carbon cycle might be a flux from one sphere to another sphere, represented by the big arrow, but that that initial flux might cause other movements in the cycle too. It is a carbon cycle after all what moves into one sphere will eventually move into other spheres. Emphasize that the cycle moves at different speeds and that some movements between spheres happen relatively quickly while others take a really long time.
- Take this opportunity to tell your students that scientists are still studying the carbon cycle and do not completely understand how all of the details work. For example, as humans release more carbon into the atmosphere, some of it is taken up by the oceans, but scientists are not sure exactly how much carbon the ocean takes up from the atmosphere.
- Discuss which of these human alterations have impacts on the climate (all of them). Six of them put carbon into the atmosphere, where it is a component of greenhouse gases and alters the climate by absorbing and re-radiating heat. One of them takes carbon from the atmosphere and puts in into tree growth and one takes carbon from the lithosphere, but instead of releasing it to the atmosphere, it is injected back into the lithosphere. These last two alterations, planting trees and capturing carbon emissions and storing them underground, are examples of ways that humans are trying to fight climate change and reduce carbon emissions.
Discuss the following questions with your students:
- Are humans adding more carbon to the carbon cycle?No, humans are changing the amount of carbon in certain spheres, but are not changing the overall amount of carbon on the plant.
- What are humans doing to change the carbon cycle?Burning fossil fuels, farming cattle, farming rice, deforesting, manufacturing cement.
- Why are these human alterations to the carbon cycle a problem?They are increasing the amount of carbon dioxide and methane in the atmosphere, both of which are greenhouse gases. An increase in greenhouse gases leads to global climate change, which has many effects including rising sea levels, rising temperatures, increased storms, changes in rainfall, organism extinctions…
- What can humans do to decrease the amount of carbon being released into the atmosphere?Burn fewer fossil fuels by driving less, take public transportation, buy local foods, turn the lights off, plant trees, support renewable energy sources like wind and solar, capture carbon at power plants and store it underground.
carbon: an element that can be found in all living things
diffusion: mixing of particles of liquid, gases, or solids from one place to another (from higher concentration to lower concentration)
atmosphere: the gases surrounding the Earth
biosphere: the parts of the land, sea and atmosphere in which life exists
hydrosphere: all of the Earth's water, including surface water (water in oceans, lakes, and rivers), groundwater (water in soil and beneath the earth's surface), snowcover, ice, and water in the atmosphere, including water vapor
lithosphere: rocky outer layer of the Earth
Plants and their processes
photosynthesis: the process by which plants use carbon dioxide and energy from the sun to build sugar
respiration: the processes by which plant and animal cells break down sugar, which results in carbon dioxide
erosion: wearing away and movement of rock and sediment, often by water, wind, glaciers, and waves
sediment: material, such as stones or sand, deposited by water, wind, or glaciers
sedimentation: the process of laying down sediments and forming sedimentary rocks
weathering: processes by which rocks exposed to the weather change and break down
Carbon is an extremely common element on earth and can be found in all four major spheres of the planet: biosphere, atmosphere, hydrosphere, and lithosphere. Carbon is part of both the living and non-living parts of the planet, as a component in organisms, atmospheric gases, water, and rocks. The carbon contained in any of the planet’s spheres does not remain there forever. Instead, it moves from one sphere to another in an ongoing process known as the carbon cycle. The carbon cycle is extremely important on earth as it influences crucial life processes such as photosynthesis and respiration, contributes to fossil fuel formation, and impacts the earth’s climate.
Besides the relatively small additions of carbon from meteorites, the amount of carbon on the planet is stable. But, the amount of carbon in any given sphere of the planet can increase or decrease depending on the fluctuations of the carbon cycle. The cycle can be thought of in terms of reservoirs (places where carbon is stored) and flows (the movement between reservoirs). The atmosphere, the biosphere, the hydrosphere, and the lithosphere are the reservoirs and the processes by which carbon moves from one reservoir to another are the flows. Although carbon is extremely common on earth, pure carbon is not common. Rather, carbon is usually bound to other elements in compounds. Thus, when carbon moves or cycles, it is usually doing so within compounds, such as carbon dioxide and methane.
The many processes that move carbon from one place to another happen on different time scales. Some of them happen on short time scales, such as photosynthesis, which moves carbon from the atmosphere into the biosphere as plants extract carbon dioxide from the atmosphere. Some carbon cycle processes happen over much longer time scales. For example, in the ocean, organisms with calcium carbonate skeletons and shells die and some of their remains, those that don’t decompose, sink towards the ocean floor. Upon reaching the ocean floor, the carbon that was stored in their bodies becomes part of the carbon-rich sediment and is eventually carried along, via plate tectonic movement, to subduction zones where it is converted into metamorphic rock. These two examples show the extreme variety of processes that take place in the carbon cycle.
In general, the short-term carbon cycle encompasses photosynthesis and respiration. On land, there is a flow of carbon from the atmosphere to plants with photosynthesis and then a flow back to the atmosphere with plant and animal respiration and decomposition. For aquatic plants, photosynthesis involves taking carbon dioxide dissolved in the water around them and respiration and decomposition put carbon dioxide back into the water. In addition to moving between plants and the atmosphere or the water, carbon dioxide is also constantly moving between the atmosphere and water via diffusion. The long-term carbon cycle encompasses more of the lithospheric processes. It involves the weathering and erosion of carbon-containing rocks, the accumulation of carbon-rich plant and animal material in sediments, and the slow movement of those sediments through the rock cycle.
The entire carbon cycle is composed of even more specific flows between the atmosphere, biosphere, hydrosphere, and lithosphere than those discussed here. Although there are more specific details involved in the earth’s complicated carbon cycle, this version highlights some of the most important components and will teach students the overall concept that carbon is limited and moves through the different spheres of the planet. For more detailed carbon cycle information investigate the resources and references listed at the end of the lesson plan.
There are natural fluctuations in the carbon cycle, but humans have been changing the carbon flows on earth at an unnatural rate. The major human-induced changes in the carbon cycle result in increased carbon dioxide (CO2) and methane (CH4) in the atmosphere. The largest source of this change is burning fossil fuels, but other actions such as deforestation, cement manufacturing, cattle farming, and rice farming also contribute to this change in the carbon cycle.
Humans use fossil fuels such as oil, coal, and natural gas for a variety of purposes including powering our vehicles, producing electricity, heating and cooling our buildings, and producing goods such as plastics. Fossil fuels are formed over millions of years from buried plant and animal material that undergoes dramatic changes due to temperature and pressures at depth. In general, coal is derived from terrestrial plant material, while oil and natural gas are derived primarily from microscopic marine plants and animals. When we burn these fossil fuels, we take carbon that has been stored underground for a very long time and put it into the atmosphere.
Deforestation causes carbon to be released into the atmosphere for a number of reasons. First, trees that are cut are often burned, which immediately releases the carbon stored in the trees into the atmosphere. Second, deforestation impacts both the temperature and stability of the soil. Since soils contain a significant amount of carbon, changes that affect the soil can affect the carbon stored in the soil. Deforestation results in more soil erosion because trees are no longer there to stabilize the soil. Eroded soil and the carbon it contains often end up in rivers and streams and eventually in the oceans, bringing carbon from the land into the hydrosphere. Soils in deforested areas are not only eroded because of the lack of trees, but they are also often tilled for agriculture. Tillage turns over the soil, releasing carbon dioxide gas contained in the soil to the atmosphere. After deforestation, soil temperatures increase because the soil is no longer covered by foliage. A rise in soil temperature causes the rate of bacterial decomposition to increase, which results in increased carbon release to the atmosphere.
The process of manufacturing cement releases carbon dioxide gas to the atmosphere. To make cement, calcium carbonate is heated in a kiln to produce lime and carbon dioxide. The lime is incorporated with other materials to make the cement, but the carbon dioxide is released to the atmosphere. In the United States, this process releases approximately 7 to 10 million metric tons of carbon per year. Although not one of the very top contributors to carbon dioxide emissions, cement manufacturing is still a significant and growing source of carbon emissions worldwide.
Cattle farming and rice farming both release methane gas to the atmosphere. Flooded rice paddies are considered one of the highest releasers of methane. When rice paddies are flooded, the underwater organic matter undergoes decomposition and methane is released. This also occurs in natural wetlands. Cattle farming also contributes significantly to methane emissions. Cattle belches and flatulence release methane because bacteria in the animals’ guts break down food and convert some of it to methane gas. Both cattle and rice farming are on the rise worldwide and thus these sources of greenhouse gases are becoming more and more of a concern. Methane emissions are also especially concerning because methane is a much stronger greenhouse gas than carbon dioxide, meaning that each molecule of methane warms the earth substantially more than each molecule of carbon dioxide.
Because carbon dioxide (CO2) and methane (CH4) are greenhouse gases that help to control the temperature of the planet, human-induced increases in atmospheric carbon levels are resulting in a host of climatic changes on our planet. These changes include temperature increases, rising sea level, changes in rainfall patterns, increased storms, and organism extinctions. An understanding of the carbon cycle is especially important at this time in human history because of the dramatic and consequential alterations we are making to the cycle.
People are currently taking many different actions, attempting to slow climate change. They are attempting to both lessen the amount of carbon that is emitted to the atmosphere and to take carbon out of the atmosphere and store it elsewhere. Some of the ways to decrease the amount of carbon emitted to the atmosphere include driving less, using energy efficient appliances, switching to solar and wind power, and capturing carbon from power plants and other stationary sources and pumping it underground for storage. This is called carbon capture and storage or carbon sequestration and people have been using this technique in oil fields for a long time. Scientists are currently researching carbon capture and storage methods to try to determine whether this technique can be used on a large scale to help slow climate change. Mitigating climate change by actually taking carbon out of the atmosphere can be accomplished with several different methods. Simply planting more trees takes carbon out of the atmosphere, because plants take carbon from the atmosphere to perform photosynthesis. Other methods for taking carbon dioxide out of the atmosphere include capturing carbon dioxide gas and converting it back into usable fuel. This is an ongoing research topic and although there are currently many viable options for decreasing the amount of carbon in the atmosphere, the future may hold other possibilities as well.
The Biosphere 2 project was launched in 1984 by businessman and philanthropist Ed Bass and systems ecologist John P. Allen, with Bass providing US$150 million in funding until 1991.  Bass and Allen had met in the 1970s at the Synergia Ranch, a counterculture community led by Allen, who advocated Buckminster Fuller's "Spaceship Earth" concept and explored the idea of biospheres as a refuge from disasters such as nuclear war.  Several other former members of Synergia Ranch also joined the Biosphere 2 project. 
Construction was carried out between 1987 and 1991 by Space Biosphere Ventures, a joint venture whose principal officers were John P. Allen, inventor and executive chairman Margaret Augustine, CEO Marie Harding, vice-president of finance Abigail Alling, vice president of research Mark Nelson, director of space and environmental applications, William F. Dempster, director of system engineering, and Norberto Alvarez-Romo, vice president of mission control. [ citation needed ]
It was named "Biosphere 2" because it was meant to be the second fully self-sufficient biosphere, after the Earth itself ("Biosphere 1").
The glass and spaceframe facility is located in Oracle, Arizona at the base of the Santa Catalina Mountains, about 50 minutes north of Tucson. Its elevation is around 4,000 feet (1,200 m) above sea level. 
The above-ground physical structure of Biosphere 2 was made of steel tubing and high-performance glass and steel frames. The frame and glazing materials were designed and made to specification by a firm run by a one-time associate of Buckminster Fuller, Peter Jon Pearce (Pearce Structures, Inc.).   The window seals and structures had to be designed to be almost perfectly airtight, such that the air exchange would be extremely low, permitting tracking of subtle changes over time. The patented airtight sealing methods, developed by Pearce and William Dempster, achieved a leak rate of less than 10% per year. Without such tight closure, the slow decline of oxygen which occurred at a rate of less than 1 ⁄ 4 % per month during the first two-year closure experiment might not have been observed.  
During the day, the heat from the sun caused the air inside to expand and during the night it cooled and contracted. To avoid having to deal with the huge forces that maintaining a constant volume would create, the structure had large diaphragms kept in domes called "lungs" or variable volume structures. 
Since opening a window was not an option, the structure also required a sophisticated system to regulate temperatures within desired parameters, which varied for the different biomic areas. Though cooling was the largest energy need, heating had to be supplied in the winter and closed loop pipes and air handlers were key parts of the energy system. An energy center on site provided electricity and heated and cooled water, employing natural gas and backup generators, ammonia chillers and water cooling towers. 
The first closed mission lasted from September 26, 1991 to September 26, 1993. The crew were: medical doctor and researcher Roy Walford, Jane Poynter, Taber MacCallum, Mark Nelson, Sally Silverstone, Abigail Alling, Mark Van Thillo, and Linda Leigh. 
The agricultural system produced 83% of the total diet, which included crops of bananas, papayas, sweet potatoes, beets, peanuts, lablab and cowpea beans, rice, and wheat.   Especially during the first year, the eight inhabitants reported continual hunger. Calculations indicated that Biosphere 2's farm was amongst the highest producing in the world "exceeding by more than five times that of the most efficient agrarian communities of Indonesia, southern China, and Bangladesh." 
They consumed the same low-calorie, nutrient-dense diet that Roy Walford had studied in his research on extending lifespan through diet.  Medical markers indicated the health of the crew during the two years was excellent. They showed the same improvement in health indices such as lowering of blood cholesterol, blood pressure, enhancement of immune system. They lost an average of 16% of their pre-entry body weight before stabilizing and regaining some weight during their second year.  Subsequent studies showed that the biospherians' metabolism became more efficient at extracting nutrients from their food as an adaptation to the low-calorie, high nutrient diet.  "The overall health of the biospherians crews inside Biosphere 2 confirm that the original design of the Biosphere 2 technosphere systems did avoid a buildup of toxins, and the bioregenerative technologies and life systems inside Biosphere 2 maintained a healthy environment." 
Some of the domestic animals that were included in the agricultural area during the first mission included: four African pygmy goats and one billy goat 35 hens and three roosters (a mix of Indian jungle fowl (Gallus gallus), Japanese silky bantam, and a hybrid of these) two sows and one boar Ossabaw dwarf pigs and tilapia fish grown in a rice and azolla pond system originating millennia ago in China. 
A strategy of "species-packing" was practiced to ensure that food webs and ecological function could be maintained if some species did not survive. The fog desert area became more chaparral in character due to condensation from the space frame. The savannah was seasonally active its biomass was cut and stored by the crew as part of their management of carbon dioxide. Rainforest pioneer species grew rapidly, but trees there and in the savannah suffered from etiolation and weakness caused by lack of stress wood, normally created in response to winds in natural conditions. Corals reproduced in the ocean area, and crew helped maintain ocean system health by hand-harvesting algae from the corals, manipulating calcium carbonate and pH levels to prevent the ocean becoming too acidic, and by installing an improved protein skimmer to supplement the algae turf scrubber system originally installed to remove excess nutrients.  The mangrove area developed rapidly but with less understory than a typical wetland possibly because of reduced light levels.  Nevertheless, it was judged to be a successful analogue to the Everglades area of Florida where the mangroves and marsh plants were collected. 
Biosphere 2, because of its small size and buffers, and concentration of organic materials and life, had greater fluctuations and more rapid biogeochemical cycles than are found in Earth's biosphere.  Most of the introduced vertebrate species and virtually all of the pollinating insects died, though there was reproduction of plants and animals.  Insect pests, like cockroaches, flourished. Many insects had been included in original species mixes in the biomes but a globally invasive tramp ant species, Paratrechina longicornis, unintentionally sealed in, had come to dominate other ant species.  The planned ecological succession in the rainforest and strategies to protect the area from harsh incident sunlight and salt aerosols from the ocean worked well, and a surprising amount of the original biodiversity persisted.  Biosphere 2 in its early ecological development was likened to an island ecology. 
Group dynamics: psychology, conflict, and cooperation Edit
Much of the evidence for isolated human groups comes from psychological studies of scientists overwintering in Antarctic research stations.  The study of this phenomenon is "confined environment psychology" (cf. environmental psychology), and according to Jane Poynter   it was known to be a challenge and often crews split into factions. 
Before the first closure mission was half over, the group had split into two factions and, according to Poynter, people who had been intimate friends had become implacable enemies, barely on speaking terms.  Others point out that the crew continued to work together as a team to achieve the experiment's goals, mindful that any action that harmed Biosphere 2 might imperil their own health. This is in contrast to other expeditions where internal frictions can lead to unconscious sabotage of each other and the overall mission. All of the crew felt a very strong and visceral bond with their living world.  They kept air and water quality, atmospheric dynamics and health of the life systems constantly in their attention in a very visceral and profound way. This intimate "metabolic connection" enabled the crew to discern and respond to even subtle changes in the living systems.  (Alling et al., 2002 Alling and Nelson, 1993). "Appreciation of the value of biosphere interconnectedness and interdependency was appreciated as both an everyday beauty and a challenging reality",  Walford later acknowledged "I don't like some of them, but we were a hell of a team. That was the nature of the factionalism. but despite that, we ran the damn thing and we cooperated totally". 
The factions inside the bubble formed from a rift and power struggle between the joint venture partners on how the science should proceed, as biospherics or as specialist ecosystem studies (perceived as reductionist). The faction that included Poynter felt strongly that increasing research should be prioritized over degree of closure. The other faction backed project management and the overall mission objectives. On February 14, a portion of the Scientific Advisory Committee (SAC) resigned.  Time Magazine wrote: "Now, the veneer of credibility, already bruised by allegations of tamper-prone data, secret food caches and smuggled supplies, has cracked . the two-year experiment in self-sufficiency is starting to look less like science and more like a $150 million stunt".  In fact, the SAC was dissolved because it had deviated from its mandate to review and improve scientific research and became involved in advocating management changes. A majority of the SAC members chose to remain as consultants to Biosphere 2. The SAC's recommendations in their report were implemented including a new Director of Research [Dr. Jack Corliss], allowing import/export of scientific samples and equipment through the facility airlocks to increase research and decrease crew labor, and to generate a formal research program. Some sixty-four projects were included in the research program that Walford and Alling spearheaded developing. 
Undoubtedly the lack of oxygen and the calorie-restricted, nutrient-dense diet  contributed to low morale.  The Alling faction feared that the Poynter group were prepared to go so far as to import food, if it meant making them fitter to carry out research projects. They considered that would be a project failure by definition.
In November 1992, the hungry Biospherians began eating seed stocks that had not been grown inside the Biosphere 2.  Poynter made Chris Helms, PR Director for the enterprise, aware of this. She was promptly dismissed by Margret Augustine, CEO of Space Biospheres Ventures, and told to come out of the biosphere. This order was, however, never carried out. Poynter writes  that she simply decided to stay put, correctly reasoning that the order could not be enforced without effectively terminating the closure.
Isolated groups tend to attach greater significance to group dynamic and personal emotional fluctuations common in all groups. Some reports from polar station crews exaggerated psychological problems.  So, although some of the first closure team thought they were depressed, psychological examination of the biospherians showed no depression and fit the explorer/adventurer profile, with both women and men testing very similar to astronauts.  One of the psychologists noted, "If I was lost in the Amazon and was looking for a guide to get out, and to survive with, then [the biospherian crew] would be top choices." 
Among the problems and miscalculations encountered in the first mission were unanticipated condensation making the "desert" too wet, population explosions of greenhouse ants and cockroaches, morning glories overgrowing the rainforest area, blocking out other plants and less sunlight (40–50% of outside light) entering the facility than originally anticipated. Biospherians intervened to control invasive plants when needed to preserve biodiversity, functioning as "keystone predators". In addition, construction itself was a challenge for example, it was difficult to manipulate the bodies of water to have waves and tidal changes.   Engineers came up with innovative solutions to supplement natural functions the Earth's biosphere normally performs, e.g. vacuum pumps to create gentle waves in the ocean without endangering marine biota, sophisticated heating and cooling systems. All the technology was selected to minimize outgassing and discharge of harmful substances which might damage Biosphere 2's life.  
There was controversy when the public learned that the project had allowed an injured member to leave and return, carrying new material inside. The team claimed the only new supplies brought in were plastic bags, but others accused them of bringing food and other items. More criticism was raised when it was learned that, likewise, the project injected oxygen in January 1993 to make up for a failure in the balance of the system that resulted in the amount of oxygen steadily declining.  Some thought that these criticisms ignored that Biosphere 2 was an experiment where the unexpected would occur, adding to knowledge of how complex ecologies develop and interact, not a demonstration where everything was known in advance.  H.T. Odum noted: "The management process during 1992–1993 using data to develop theory, test it with simulation, and apply corrective actions was in the best scientific tradition. Yet some journalists crucified the management in the public press, treating the project as if it was an Olympic contest to see how much could be done without opening the doors". 
The oxygen inside the facility, which began at 20.9%, fell at a steady pace and after 16 months was down to 14.5%. This is equivalent to the oxygen availability at an elevation of 4,080 metres (13,390 ft).  Since some biospherians were starting to have symptoms like sleep apnea and fatigue, Walford and the medical team decided to boost oxygen with injections in January and August 1993. The oxygen decline and minimal response of the crew indicated that changes in air pressure are what trigger human adaptation responses. These studies enhanced the biomedical research program. 
2 levels was a particular challenge, and a source of controversy regarding the Biosphere 2 project's alleged misrepresentation to the public. Daily fluctuation of carbon dioxide dynamics was typically 600 ppm because of the strong drawdown during sunlight hours by plant photosynthesis, followed by a similar rise during the nighttime when system respiration dominated. As expected, there was also a strong seasonal signature to CO
2 levels, with wintertime levels as high as 4,000–4,500 ppm and summertime levels near 1,000 ppm. The crew worked to manage the CO
2 by occasionally turning on a CO
2 scrubber, activating and de-activating the desert and savannah through control of irrigation water, cutting and storing biomass to sequester carbon, and utilizing all potential planting areas with fast-growing species to increase system photosynthesis.  In November 1991, investigative reporting in The Village Voice alleged that the crew had secretly installed the CO
2 scrubber device, and claimed that this violated Biosphere 2's advertised goal of recycling all materials naturally.  Others pointed out there was nothing secret about the carbon dioxide device and it constituted another technical system augmenting ecological processes. The carbon precipitator could reverse the chemical reactions and thus release the stored carbon dioxide in later years when the facility might need additional carbon. 
Many suspected the drop in oxygen was due to microbes in the soil. [ citation needed ] The soils were selected to have enough carbon to provide for the plants of the ecosystems to grow from infancy to maturity, a plant mass increase of perhaps 20 short tons (18,000 kg).  The release rate of that soil carbon as carbon dioxide by respiration of soil microbes was an unknown that the Biosphere 2 experiment was designed to reveal. Subsequent research showed that Biosphere 2's farm soils had reached a more stable ratio of carbon and nitrogen, lowering the rate of CO
2 release, by 1998. 
The respiration rate was faster than the photosynthesis (possibly in part due to relatively low light penetration through the glazed structure and the fact that Biosphere 2 started with a small but rapidly increasing plant biomass) resulting in a slow decrease of oxygen. A mystery accompanied the oxygen decline: the corresponding increase in carbon dioxide did not appear. This concealed the underlying process until an investigation by Jeff Severinghaus and Wallace Broecker of Columbia University's Lamont Doherty Earth Observatory using isotopic analysis showed that carbon dioxide was reacting with exposed concrete inside Biosphere 2 to form calcium carbonate in a process called carbonatation, thereby sequestering both carbon and oxygen. 
After Biosphere 2's first mission, extensive research and system improvements were undertaken, including sealing concrete to prevent the uptake of carbon dioxide.
The second mission began on March 6, 1994, with an announced run of ten months. The crew was Norberto Alvarez-Romo (Capt.), John Druitt, Matt Finn, Pascale Maslin, Charlotte Godfrey, Rodrigo Romo and Tilak Mahato. The second crew achieved complete sufficiency in food production. 
On April 1, 1994, a severe dispute within the management team led to the ousting of the on-site management by federal marshals serving a restraining order, and financier Ed Bass hired Steve Bannon, then-manager of the Bannon & Co. investment banking team from Beverly Hills, California, to run Space Biospheres Ventures. The project was put into receivership and an outside management team was installed for the receiver to turn around the floundering project. The reason for the dispute was threefold. Mismanagement of the mission had caused terrible publicity, financial mismanagement and lack of research. People [ who? ] alleged gross financial mismanagement of the project, leading to a loss of $25 million in fiscal year 1992.  Some crew members and staff were concerned about Bannon, who had previously investigated cost overruns at the site two former Biosphere 2 crew members flew back to Arizona to protest the hire and broke into the compound to warn current crew members that Bannon and the new management would jeopardize their safety. 
At 3 a.m. on April 5, 1994, Abigail Alling and Mark Van Thillo, members of the first crew, allegedly vandalized the project from outside,  opening one double-airlock door and three single door emergency exits, leaving them open for about 15 minutes. Five panes of glass were also broken. Alling later told the Chicago Tribune that she "considered the Biosphere to be in an emergency state. In no way was it sabotage. It was my responsibility."  About 10% of the Biosphere's air was exchanged with the outside during this time, according to systems analyst Donella Meadows, who received a communication from Alling saying that she and Van Thillo judged it their ethical duty to give those inside the choice of continuing with the drastically changed human experiment or leaving, as they didn't know what the crew had been told of the new situation. “On April 1, 1994, at approximately 10 AM . limousines arrived on the biosphere site . with two investment bankers hired by Mr. Bass . They arrived with a temporary restraining order to take over direct control of the project . With them were 6-8 police officers hired by the Bass organization . They immediately changed locks on the offices . All communication systems were changed (telephone and access codes), and [we] were prevented from receiving any data regarding safety, operations, and research of Biosphere 2." Alling emphasized several times in her letter that the “bankers” who suddenly took over “knew nothing technically or scientifically, and little about the biospherian crew.” 
Four days later, the captain Norberto Alvarez-Romo (by then married to Biosphere 2 chief executive Margaret Augustine) precipitously left the Biosphere for a "family emergency" after his wife's suspension.  He was replaced by Bernd Zabel, who had been nominated as captain of the first mission but who was replaced at the last minute. Two months later, Matt Smith replaced Matt Finn. [ citation needed ]
The ownership and management company Space Biospheres Ventures was dissolved on June 1, 1994. This left the scientific and business management of the mission to the interim turnaround team, who had been contracted by the financial partner, Decisions Investment Co. 
Mission 2 was ended prematurely on September 6, 1994. No further total system science has emerged from Biosphere 2 as the facility was changed by Columbia University from a closed ecological system to a "flow-through" system where CO
2 could be manipulated at desired levels. 
Steve Bannon left Biosphere 2 after two years, but his departure was marked by an "abuse of process" civil lawsuit filed against Space Biosphere Ventures by the former crew members who had broken in.  Leading managers of Biosphere 2 from the original founding group stated both abusive behaviour by Bannon and others, and that the bankers’ actual goal was to destroy the experiment.  During a 1996 trial, Bannon testified that he had called one of the plaintiffs, Abigail Alling, a "self-centered, deluded young woman" and a "bimbo."  He also testified that when the woman submitted a five-page complaint outlining safety problems at the site, he promised to shove the complaint "down her throat." Bannon attributed this to "hard feelings and broken dreams."  At the end of the trial, the court ruled in favor of the plaintiffs and ordered Space Biosphere Ventures to pay them $600,000, but also ordered the plaintiffs to pay the company $40,089 for the damage they had caused. 
A special issue of the Ecological Engineering journal edited by Marino and Howard T. Odum was published in 1999 as "Biosphere 2: Research Past and Present" represents the most comprehensive assemblage of collected papers and findings from Biosphere 2.  The papers range from calibrated models that describe the system metabolism, hydrologic balance, and heat and humidity, to papers that describe rainforest, mangrove, ocean, and agronomic system development in this carbon dioxide-rich environment.   Though several dissertations and many scientific papers used data from the early closure experiments at Biosphere 2, much of the original data has never been analyzed and is unavailable or lost, perhaps due to scientific politics and in-fighting.  
The historian of science Rebecca Redier has claimed that because Biosphere 2's creators were perceived as outsiders to academic science, the project was scrutinized but poorly understood in the media, and that this scrutiny ceased after Columbia University assumed management, because it was assumed they were "proper" scientists. 
Praise and criticism Edit
One view of Biosphere 2 was that it was "the most exciting scientific project to be undertaken in the United States since President John F. Kennedy launched us toward the moon".  Others called it "New Age drivel masquerading as science".  John Allen and Roy Walford did have mainstream credentials. John Allen held a degree in Metallurgical-Mining Engineering from the Colorado School of Mines, and an MBA from the Harvard Business School.   Roy Walford received his doctorate of medicine from the University of Chicago and taught at UCLA as a Professor of Pathology for 35 years. Mark Nelson obtained his Ph.D. in 1998 under Professor H.T. Odum in ecological engineering further developing the constructed wetlands used to treat and recycle sewage in Biosphere 2,  to coral reef protection along the Yucatán coast where the corals were collected.  Linda Leigh obtained her PhD with a dissertation on biodiversity and the Biosphere 2 rainforest working with Odum.  Abigail Alling, Mark van Thillo and Sally Silverstone helped start the Biosphere Foundation where they worked on coral reef and marine conservation and sustainable agricultural systems.  Jane Poynter and Taber MacCallum co-founded Paragon Space Development Corporation which has studied the first mini-closed system and the first full animal life cycle in space and assisted in setting world records in high altitude descents. 
Questioning the credentials of the participants (despite the contribution in the preparation phase of Biosphere 2 of worldwide top-level scientists and among others the Russian Academy of Sciences), Marc Cooper wrote that "the group that built, conceived, and directs the Biosphere project is not a group of high-tech researchers on the cutting edge of science but a clique of recycled theater performers that evolved out of an authoritarian—and decidedly non-scientific—personality cult".  He was referring to the Synergia Ranch in New Mexico, where indeed many of the Biospherians did practice theater under John Allen's leadership, and began to develop the ideas behind Biosphere 2.  They also founded the Institute of Ecotechnics  and began innovative field projects in challenging biomes to advance the healthy integration of human technologies and the environment where many of the biospherian candidates gained experience in operating real-time complex projects.  
One of their own scientific consultants was earlier critical. Dr. Ghillean Prance, director of the Royal Botanical Gardens in Kew, designed the rainforest biome inside the Biosphere. Although he later changed his opinion, acknowledging the unique scope of this experiment and contributed to its success as a consultant, in a 1983 interview (8 years before the start of the experiment), Prance said, "I was attracted to the Institute of Ecotechnics because funds for research were being cut and the institute seemed to have a lot of money which it was willing to spend freely. Along with others, I was ill-used. Their interest in science is not genuine. They seem to have some sort of secret agenda, they seem to be guided by some sort of religious or philosophical system." Prance went on in the 1991 newspaper interview to say "they are visionaries . And maybe to fulfill their vision they have become somewhat cultlike. But they are not a cult, per se . I am interested in ecological restoration systems. And I think all sorts of scientific things can come of this experiment, far beyond the space goal . When they came to me with this new project, they seemed so well organized, so inspired, I simply decided to forget the past. You shouldn't hold their past against them." 
Poynter in her memoir rebuts the critique that because some of the creative team of Biosphere 2 were not credentialed scientists, the results of the endeavor are invalid. "Some reporters hurled accusations that we were unscientific. Apparently because many of the SBV managers were not themselves degreed scientists, this called into question the entire validity of the project, even though some of the world’s best scientists were working vigorously on the project’s design and operation. The critique was not fair. Since leaving Biosphere 2, I have run a small business for ten years that sent experiments on the shuttle and to the space station, and is designing life support systems for the replacement shuttle and future moon base. I do not have a degree, not even an MBA from Harvard, as John [Allen] had. I hire scientists and top engineers. Our company’s credibility is not called into question because of my credentials: we are judged on the quality of our work".  H.T. Odum noted that mavericks and outsiders have often contributed to the development of science: "The original management of Biosphere 2 was regarded by many scientists as untrained for lack of scientific degrees, even though they had engaged in a preparatory study program for a decade, interacting with the international community of scientists including the Russians involved with closed systems. The history of science has many examples where people of atypical background open science in new directions, in this case implementing mesocosm organization and ecological engineering with fresh hypotheses". 
The Biosphere 2 Science Advisory Committee, chaired by Tom Lovejoy of the Smithsonian Institution, in its report of August 1992 reported: "The committee is in agreement that the conception and construction of Biosphere 2 were acts of vision and courage. The scale of Biosphere 2 is unique and Biosphere 2 is already providing unexpected scientific results not possible through other means (notably the documented, unexpected decline in atmospheric oxygen levels.) Biosphere 2 will make important scientific contributions in the fields of biogeochemical cycling, the ecology of closed ecological systems, and restoration ecology." Columbia University assembled outside scientists to evaluate the potential of the facility after they took over management, and concluded the following: "A group of world-class scientists got together and decided the Biosphere 2 facility is an exceptional laboratory for addressing critical questions relative to the future of Earth and its environment." 
Ongoing research following the initial enclosure has produced positive results for current ecological understanding. Mark Nelson writes, "Several years of research on Biosphere 2's ocean demonstrated the devastating impacts from elevated atmospheric CO2 [. ] coral reef was studied at 200 ppm, 350 ppm, 700 ppm, and 1200 ppm of CO2. Corals grew twice as fast at the lower levels [. ] compared to the 350 ppm levels in the 1990's Earth atmosphere. [. ] At 1200 ppm, coral growth declined 90 percent." Frank Press, a former secretary for the National Academy of Sciences, described the interaction as, "the first unequivocal experimental confirmation of the human impact on the planet." 
In December 1995 the Biosphere 2 owners transferred management to Columbia University of New York City.  Columbia ran Biosphere 2 as a research site and campus until 2003.  Subsequently, management reverted to the owners.
In 1996, Columbia University changed the virtually airtight, materially closed structure designed for closed system research, to a "flow-through" system, and halted closed system research. They manipulated carbon dioxide levels for global warming research, and injected desired amounts of carbon dioxide, venting as needed.  During Columbia's tenure, students from Columbia and other colleges and universities would often spend one semester at the site. 
Research during Columbia's tenure demonstrated the devastating impacts on coral reefs from elevated atmospheric CO
2 and acidification that will result from continued global climate change.  Frank Press, former president of the National Academy of Sciences, described these interactions between atmosphere and ocean, taking advantage of the highly controllable ocean mesocosm of Biosphere 2, as the “first unequivocal experimental confirmation of the human impact on the planet”. 
Studies in Biosphere 2’s terrestrial biomes showed that a saturation point was reached with elevated CO
2 beyond which they are unable to uptake more. The studies' authors noted that the striking differences between the Biosphere 2 rainforest and desert biomes in their whole system responses “illustrates the importance of large-scale experimental research in the study of complex global change issues". 
In January 2005, Decisions Investments Corporation, owner of Biosphere 2, announced that the project's 1,600-acre (650 ha) campus was for sale. They preferred a research use to be found for the complex but were not excluding buyers with different intentions, such as big universities, churches, resorts, and spas.  In June 2007 the site was sold for $50 million to CDO Ranching & Development, L.P. 1,500 houses and a resort hotel were planned, but the main structure was still to be available for research and educational use. 
On June 26, 2007, the University of Arizona announced it would take over research at the Biosphere 2. The announcement ended fears that the structure would be demolished. University officials said private gifts and grants enabled them to cover research and operating costs for three years with the possibility of extending funding for ten years.  It was extended for ten years, and is now engaged in research projects including research into the terrestrial water cycle and how it relates to ecology, atmospheric science, soil geochemistry, and climate change. In June 2011, the university announced that it would assume full ownership of Biosphere 2, effective July 1. 
CDO Ranching & Development donated the land, Biosphere buildings and several other support and administrative buildings. In 2011, the Philecology Foundation (a nonprofit research foundation founded by Ed Bass) pledged US$20 million for the ongoing science and operations.  In 2017, Bass donated another $30 million to the University of Arizona in support of Biosphere 2, endowing two academic positions and setting up the "Philecology Biospheric Research Endowment Fund". 
Science camps are also held on the premises. These have included a week-long 'space camp' for university undergraduates, and overnight camps for school students.  
There are many small-scale research projects at Biosphere 2, as well as several large-scale research projects including: