Colorado State University-Pueblo
Towards a Biosphere to Create and Monitor Environmental Conditions
Rosa M. Munoz[*] and Matthew S. Garcia[†],
Colorado State University-Pueblo, Pueblo, CO 81001, USA
Brandon M. Martinez[‡]
Colorado State University-Pueblo, Pueblo, CO 81001, USA
This research project for the spring 2005 semester is to design and construct a closed ecological system in which plant life and possible insect life may be self-sustained. The main goal, however, is to demonstrate the creation of oxygen gas by utilizing the plant Arabidopsis Thaliana. This project will succeed by utilizing different fields of knowledge including Engineering, Chemistry and Biology. The biosphere will be self-sustaining, will contain one uniform environment, and will contain only a few plants. Furthermore, this paper discusses the construction of a table-top experimental design and measuring devices used to quantify the oxygen levels and other environmental variables, such as relative humidity, temperature and light intensity. The system will be completely enclosed from its beginning to its conclusion. This paper will report on our initial findings and the underlying scientific principles of creating a biosphere. It is a contribution for further research in providing oxygen needed for survival of future outposts on other planets/moons in space.
I.Introduction
F
rom the time of its discovery, Mars has been a topic of major interest to mankind. Following the Moon, the Red Planet has attracted more spacecraftthan any other object in the solar system, despite the tremendous challenge of visiting and observing it. Therefore major challenges are visitation, exploration and colonization.
Mars has an average temperature of –60 oC and the atmosphere contains 95 percent CO2, indicating that direct habitation is almost impossible. Therefore, other means of colonizing Mars are being explored, such as the establishment of permanent bases on it – and the creation of an artificial biosphere necessary for human life.
Biospheres are meant to be life-sustaining and self-sufficient. This means they have to be capable of recycling food, water and air. Although they are similar, a biosphere is not a greenhouse. A greenhouse provides an ideal growing area for plants, and efficiently nourishes them; however, it is not entirely impervious. Conversely, the biosphere is designed to sustain possible human, animal and plant life and once initial conditions are set, they can not be altered. Also, a greenhouse can be opened at any time and allows therefore matter exchange. On contrary the biosphere is sealed from its onset from all external influences except light. Efforts are currently being made to build and observe biospheres and one of the most successful so far has been Biosphere 2 located in Arizona. However, it has encountered major challenges in air recycling as far as the depletion of oxygen and overall increase in toxic gases.
The objective of the project is to build and observe a tabletop (scaled) biosphere to observe the increase in oxygen content. Since it has been proven that the absence of humans has little effect on the air cycle, the microbes in the soil would fully complete the air cycle by producing carbon dioxide. To accomplish this task, oxygen, humidity, temperature, and light intensity will be measured. The results produced by this experiment may advance the desire of man to eventually inhabit Mars.
II.Literature Review
In this section of the paper a summery of different biosphere experiments is given. It shall introduce the reader to previous attempts of biosphere creation and give and give an overview of problems and difficulties in the construction process.
A.Earth Applications of Closed Ecological Systems: Relevance to the Development of Sustainability in our Global Biosphere1
Nelson and his coauthors realize the importance of Earth’s environmental ecosystem, and they point out directly that Earth’s natural resources are being depleted by our own fault. They recommend that mankind start changing the way they view their home. The scientists recognize, however, that some of Earth’s inhabitants appreciate what it provides to them, and that the citizens of this world are too accustomed to having unlimited resources provided to them. Therefore, they will not know how to adjust when those resources are depleted or in short supply. Nelson et al. recommend that society starts recycling, conserving, and sustaining the resources that they embrace; for the resources may be in limited supply in the future. These researchers urge society to recycle industrial by- and end products so that there is less pollution and contamination in our atmosphere and propose an increase of reliance on renewable natural resources such as the light from the sun. By developing an understanding of how the Earth operates, further research into methods of life-sustaining modules will be conducted; so that if Earth is ever without its natural resources indispensable to life, civilization may continue elsewhere.
Given is a basic overview of the many biosphere experiments that have been conducted over the past fifty years, beginning with the microcosm or miniaturized ecosystem. They state, that this is the ideal tool for understanding how an enclosed biosphere of a larger magnitude would operate. It was originally created as a teaching instrument for the classroom, when it soon became evident that it could be used for more advanced research. The only requirement necessary for the survival of these ecosystems is that they maintain a certain level of energy input from the sun or artificial lights. Such models are useful in drawing conclusions about the behaviors and patterns found in Earth’s natural ecosystem.
The second system discussed, was the small laboratory flasks containing microbes, alga and occasionally small brine shrimp. These ecosystems are relatively contained within a flask with volumes ranging between 100 ml to 5 l. They also require a minimum amount of light necessary to grow and adequate temperatures under which to subsist. These small systems have been known to survive for extended periods of time, and a few of them have lasted for several decades.
The third closed ecological system is the NASA CELSS (Closed Ecological Life-Support System). The scientists of this experiment discovered new ways of suppressing phytorespiration, and methods of maximizing the space within their structure. The CELSS researchers are most recently conducting experiments on the recycling of human and plant waste.
The fourth biosphere experiment was that of the Bios-3 based out of Siberia. It was the first to create a plant growing system that was located above the ground. Also, the experiment was able to sustain human occupation for 4-6 months. They were able to recycle the air from the plants and the water produced by the system. Human interaction with the biosphere was essential to its success and that the inhabitants were active in the decision-making of the system. The only component that the Bios-3 scientist lacked was that the soil they used contained microbes that were eventually harmful to the plants and that it aided in the production of harmful trace gases that could have eventually been detrimental to the health of the human occupants.
Biosphere 2 was the fifth enclosed ecological system that was discussed by these Nelson and his co-authors. They stated that the system was so effective because of the numerous biomes that had been established within the system and that each individual biome was essential for the success of the others. Included within Biosphere 2 were five ecological systems including that of the rainforest, desert, savannah, ocean and wetland, and it was designed so that the systems were dependent upon one another. According to the Nelson et al., a definite connection between this biosphere and Earth is evident; however, they believe that if humans were to construct such a structure on another planet such as Mars, it would not be successful because the environmental conditions are unlike Earth’s.
Finally, these scientists give some ideas for further research into soil conditions necessary for plant growth and maturation. They believe that by simply modifying the soil by exposure to various microorganisms before the plants are deposited, it may prevent or at least reduce the production of trace gases produced overall. Also, other phenomena such as a decrease in oxygen production or in a decrease in the atmospheric pressure may result.
B.Development and Research Program for a Soil-based Bioregenerative Agricultural System to Feed a Four Person Crew at Mars Base2
Silverstone and his colleagues suggested a plan for an establishment they call Mars on Earth, which is a simulation of a life-support system for four people, and which they hope will eventually be built on the Red Planet. However, this paper is not intended to give the overall layout of what the compound should look like or how it should be designed, for it only deals with the question of its agricultural sustainability.
In this paper, a framework is given for the humans intending to live on Mars e.g., giving a menu for a nutritional and palatable diet. Included in this Martian diet are ten plants comprised of wheat, rice, pinto beans and soybeans; each plant selected because of its heartiness, easy harvest and provision of necessary vitamins and minerals essential for a healthy human life. However, the scientists realize that they do not have an exact replica of the type of soil that they would have from the surface of the Red Planet; therefore, they know that whatever results they may have from their experiments here on Earth will be distinctly different and skewed. They believe that further research is needed in the area of Mars soil cultivation, and in the area of nutrient circulation, which is essential for a plentiful harvest. They know that the ideal soil compilation is only possible through further deliberation and experimentation.
Ideas for the recyclable materials such as human waste and the recirculation of the oxygen produced within the system are also provided. The researchers envision an agricultural system that is communitive between the system of water and air. They believe that they can design a system that could be operated not only when the two systems behave simultaneously, but also as distinctly separate and independent systems as well, as in the case of impairment. Silverstone et al. state that their enclosed agricultural system would operate most efficiently when it is totally enclosed with relatively little or no interference by outside influences. However, they believe that the system would not be harmed in any way by energy, information or material exchanges.
Since the purpose of the agricultural system is to provide food for those living inside the space capsule on the planet Mars; the engineers and scientists recommend two basic ideas for its roof, which will be the primary light source for the plants. The first idea is to utilize a roof that is partially transparent instead and the second is to utilize the sunlight by a fiber-optic roof. These are both alternatives to using a totally opaque roof, which may be detrimental to the plants and to the human inhabitants inside. These two roof ideas allow for the perfect medium of sunlight essential for plant photosynthesis and growth.
C.Beachworld3, Ecosphere4
These biospheres are sealed enclosures “containing plants and animals in perfect balance within an aquatic environment.”5 They include animal life such as small snails, crustecea, and small water-borne animals. The water-based biospheres are sun driven which helps the plants in their production of oxygen and nourishment through photosynthesis. Animals consume the oxygen, and give off the by-product carbon dioxide and other nutrients that the plants need. During the night the animals consume the oxygen while no oxygen is being created. The Beachworld was created in 1993 by a “space station engineer and two of the original Biosphere 2 crew members”6 (Ms. Jane Poynter and Mr. Taber MacCallum). The Ecosphere was developed by scientists a NASA’s Jet Propulsion Laboratory. NASA was “researching self-contained communities for space explorers to live in during long-term space flights.”7 The two scientists working on this project were Dr. Joe Hanson and Dr. Clair Folsome.
The floras in the biospheres consist of Lilly-like plants called the Chain of Stars. They are one of the smallest plants in the world; however, they provide protection as well as nutrition for the organisms of the biosphere. These plants reproduce “vegetatively”, which means that each of the leaves is a separate plant. Another plant that provides protection as well as contributes to the oxygen creation is the Hornwort. This plant is usually not eaten by the animals because of the bad taste.
The biospheres faunas consist of a variety of animals. There are many species of snails such as the Ramshorn, Pond and Trumpet snails. The snails “graze on algae and the roots of the Chain of Stars and may be seen pruning dead leaves.”8Some other animals populating the biosphere are Daphnia, Ostracods, and Copepods. These animals are near microscopic, but are very important to the food chain and to the housekeeping of the biosphere. They filter feed, which means that they “eat microscopic algae and microbes floating in the water or the debris on the bottom [of the biosphere].”9
D. Bios-3: Siberian Experiments in Bioregenerative Life Support10
This report was written and published in October of 1997. The authors of this report specialize in the areas of Biometeorology and Biophysics. NASA’s first biosphere project, was started in 1960 but dropped shortly afterwards. The most recent NASA project is called CELSS (Closed Ecological Life-Support System). The Russian Space Agency simultaneously developed a program with the primary goal of constructing and operating a life-sustaining module to be placed on the surface of the Moon or Mars. Nowadays, this same space agency has a specialized program called the Advanced Life Support Program, but it still has the same basic goal in mind.
Starting the Russian biosphere program, Boris G. Kovrov became the chief designer for the Bios-1, which was constructed in 1965 the Siberian city of Krasnoyarsk. A few years later, in 1968, the Bios-1 was slightly modified into Bios-2, with the addition of phytotrons (chambers to lift the plants above the ground). For these experiments, plants such as carrots, cucumbers and wheat were grown in the elevated chambers, which aided in the overall production of oxygen for the biosphere. Then, in 1972, the Bios-3 was constructed at a cost of about 1 million dollars. It is an underground facility which is divided into four sections with dimensions of 14 m x 9 m x 2.5 m.
Currently, the Bios-3 has three sections that are entirely devoted to the growth and cultivation of the phytotrons. The phytotrons use twenty cylindrical, vertical 6 kW xenon lamps each and the power needed to run these lamps is provided by the nearby water power plant. A cooling system called the “water jacket” is used to cool the continuously running lamps so that they do not overheat and possibly harm the plants. However, the scientists found that plants such as wheat require too much light in order to grow, which may cause an overheating of the growing lamps. They feel that crops such as potatoes and tomatoes would develop better with a period where they are not exposed to the lights, which would stimulate a dark or resting period.
Salisbury et al. added to their enclosed biosphere air tanks for maintenance of air pressure. At certain levels where the pressure went above atmospheric pressure, air was automatically pumped into those tanks. Consequently, when the outside pressure was above certain tolerances, the tanks pumped air into those chambers in order to equalize it. Overall, they had a minimum amount of air leaks with between 0.020%-0.026% lost by volume. Air was also circulated throughout the biosphere for the inhabitants and for the plants to be used in the photosynthesis processes. The scientists believed that they did not need an overly complicated air purification system, but yet relied on the natural purification processes done by the plants themselves and also on a catalytic converter; which heated the air to temperature levels between 600°C-652°C.
There were collectively three different enclosure experiments conducted inside of the Bios-3 establishment. Following each inhabitation, it was found that after many psychological and physical tests, the “crew” was in good health. Also, it was found that the amounts and quality of water, air and plants was not decreased at any time. These procedures were conducted in the middle of the winter seasons as to minimize the amount of pathogens that could possibly contaminate the experiment.
Salisbury and his co-authors give a brief analysis of the Biosphere 2; saying that the only reason that it was unsuccessful thus far is that it had an overall decrease in oxygen concentration, possibly caused by the process of respiration. They believe that too much oxygen was used in this process and that the decay of organic matter did not aid in the oxygen production process either. They also state that such a large structure could not possibly exist on such a planet as Mars or even on the surface of the Moon. These scientists reason that such a lightweight, pressurized structure would be non-existent on the surface that has nearly not air-pressure. Therefore, they make their case for their own enclosed ecological system, the Bios-3. They recommended that in order to continue further experimentation with an enclosed ecological system that the addition of a few invertebrate animals or fish would be helpful to the overall system with a minute amount of energy consumption. They advocate that further research should be made in the areas of building a lighter and drastically simplified structure.