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Revision as of 13:37, 12 October 2014
Hier fehlt der Header
Problem
That's why we target methane
Gases absorbing and emitting radiation within the thermal infrared range in the atmosphere are called greenhouse gases. They are responsible for the greenhouse effect. The main greenhouse gases are carbon dioxide, methane, nitrous oxides and fluorinated gases or, in short, F-gases.
The relative contribution of each of these greenhouse gases to climate change depends roughly on three main factors:
1. The amount of a respective gas in the atmosphere.
2. The duration of stay in the atmosphere.
3. The intensity of their impact on the global temperature.
For each of these gases a Global Warming Potential (GWP) has been calculated which is a measure of the total energy that a gas absorbs over a particular period of time compared to carbon dioxide. Besides, it is also based on the degradation rate of the respective gas. Thus the GWP describes the ability of a gas to trap heat in the atmosphere. The larger the GWP the bigger the effect of the particular gas on global warming.
As shown in the figure below, the GWPs (100 years) of the primary greenhouse gases differ significantly. Since the GWP is calculated in relation to carbon dioxide, the GWP of carbon dioxide is defined as 1. The 100 year GWP for methane is 25 implying that methane will trap 25 times more heat than carbon dioxide over the next 100 years.
Carbon dioxide is the main greenhouse gas emitted by human activities. As part of the Earth’s carbon cycle, carbon dioxide is also naturally present in the atmosphere: It is constantly exchanged between the atmosphere, ocean and land surface as it is produced and absorbed by many microorganisms, plants and animals. But human activities affect the carbon cycle by adding more carbon dioxide to the atmosphere and by damaging natural sinks, for example forests which would otherwise remove carbon dioxide from the atmosphere.
Nitrous Oxide, like carbon dioxide, is also naturally present in the atmosphere as it is part of the global nitrogen cycle: Nitrogen circulates between the atmosphere, plants, animals and bacteria breaking it down in the oceans and soils. Even though it has a variety of natural sources, human activities such as wastewater management or nitrogen fertilization increase the amount of nitrous oxide in the atmosphere. These molecules stay in the atmosphere for about 120 years but can be removed by certain types of bacteria or even destroyed by chemical reactions or ultraviolet radiation.
In contrast to other greenhouse gases, fluorinated gases do not have natural sources and only arise from human activities. F-gases are emitted through different industrial processes and many of them have a very high global warming potential in comparison to other greenhouse gases. Therefore, even very small atmospheric concentrations can have great effects on global temperatures. Additionally they have very long atmospheric lifetimes, lasting up to thousands of years. F-gases are removed from the atmosphere only when they get destroyed by sunlight in the far upper atmosphere. In general, fluorinated gases are the most potent and longest lasting sort of greenhouse gases emitted by humans.
Methane is the second most important greenhouse gas. It is emitted by several natural sources such as wetlands but also by different human activities like leakage from natural gas and livestock farming. Methane can be removed from the atmosphere by natural processes in soil and chemical reactions in the atmosphere. As its lifetime in the atmosphere is, compared to other greenhouse gases, quite short (~12 years), targeting methane emissions as a means of reducing the overall greenhouse gas emissions in a relatively short period of time is a reasonable approach to reduce global warming.
Globally around 60% of all methane emissions originate from human activites like industry, agriculture and waste management.
Even though the total methane emissions decreased by around 10% between 1990 and 2012 the emissions associated with agricultural activities did not. This is mostly due to the intensification of livestock farming. Methane is set free in the course of digestion in ruminant animals like cattle and emitted into the atmosphere. Therefore, by increasing livestock production methane emissions are increased as well.
Methane is formed in a process called methanogenesis which, for example, takes place in the rumen of cattle. However, the methane is not further utilized by any of the microorganisms living in the animal’s digestive tract nor by the animal itself, so it gets exhaled to the atmosphere and thus contributes to global warming. Read here (LINK) what has been done in the past against these emissions, or here (LINK) how exactly methanogenesis takes place.
Gases absorbing and emitting radiation within the thermal infrared range in the atmosphere are called greenhouse gases. They are responsible for the greenhouse effect. The main greenhouse gases are carbon dioxide, methane, nitrous oxides and fluorinated gases or, in short, F-gases.
The relative contribution of each of these greenhouse gases to climate change depends roughly on three main factors:
1. The amount of a respective gas in the atmosphere.
2. The duration of stay in the atmosphere.
3. The intensity of their impact on the global temperature.
For each of these gases a Global Warming Potential (GWP) has been calculated which is a measure of the total energy that a gas absorbs over a particular period of time compared to carbon dioxide. Besides, it is also based on the degradation rate of the respective gas. Thus the GWP describes the ability of a gas to trap heat in the atmosphere. The larger the GWP the bigger the effect of the particular gas on global warming.
As shown in the figure below, the GWPs (100 years) of the primary greenhouse gases differ significantly. Since the GWP is calculated in relation to carbon dioxide, the GWP of carbon dioxide is defined as 1. The 100 year GWP for methane is 25 implying that methane will trap 25 times more heat than carbon dioxide over the next 100 years.
Carbon dioxide is the main greenhouse gas emitted by human activities. As part of the Earth’s carbon cycle, carbon dioxide is also naturally present in the atmosphere: It is constantly exchanged between the atmosphere, ocean and land surface as it is produced and absorbed by many microorganisms, plants and animals. But human activities affect the carbon cycle by adding more carbon dioxide to the atmosphere and by damaging natural sinks, for example forests which would otherwise remove carbon dioxide from the atmosphere.
Nitrous Oxide, like carbon dioxide, is also naturally present in the atmosphere as it is part of the global nitrogen cycle: Nitrogen circulates between the atmosphere, plants, animals and bacteria breaking it down in the oceans and soils. Even though it has a variety of natural sources, human activities such as wastewater management or nitrogen fertilization increase the amount of nitrous oxide in the atmosphere. These molecules stay in the atmosphere for about 120 years but can be removed by certain types of bacteria or even destroyed by chemical reactions or ultraviolet radiation.
In contrast to other greenhouse gases, fluorinated gases do not have natural sources and only arise from human activities. F-gases are emitted through different industrial processes and many of them have a very high global warming potential in comparison to other greenhouse gases. Therefore, even very small atmospheric concentrations can have great effects on global temperatures. Additionally they have very long atmospheric lifetimes, lasting up to thousands of years. F-gases are removed from the atmosphere only when they get destroyed by sunlight in the far upper atmosphere. In general, fluorinated gases are the most potent and longest lasting sort of greenhouse gases emitted by humans.
Methane is the second most important greenhouse gas. It is emitted by several natural sources such as wetlands but also by different human activities like leakage from natural gas and livestock farming. Methane can be removed from the atmosphere by natural processes in soil and chemical reactions in the atmosphere. As its lifetime in the atmosphere is, compared to other greenhouse gases, quite short (~12 years), targeting methane emissions as a means of reducing the overall greenhouse gas emissions in a relatively short period of time is a reasonable approach to reduce global warming.
Globally around 60% of all methane emissions originate from human activites like industry, agriculture and waste management.
Even though the total methane emissions decreased by around 10% between 1990 and 2012 the emissions associated with agricultural activities did not. This is mostly due to the intensification of livestock farming. Methane is set free in the course of digestion in ruminant animals like cattle and emitted into the atmosphere. Therefore, by increasing livestock production methane emissions are increased as well.
Methane is formed in a process called methanogenesis which, for example, takes place in the rumen of cattle. However, the methane is not further utilized by any of the microorganisms living in the animal’s digestive tract nor by the animal itself, so it gets exhaled to the atmosphere and thus contributes to global warming. Read here (LINK) what has been done in the past against these emissions, or here (LINK) how exactly methanogenesis takes place.
Idea
The Greenhouse Effect is a well known phenomenon describing the synergy of several gases in the atmosphere of our earth, which leads to positive as well as negative consequences. Without greenhouse gases the earth would be a very cold place and life would not be possible the way we know it. Nevertheless, due to increasing emission of gases like methane and carbon dioxide the effect is further enhanced and thus causes global warming. Among other things the greenhouse gas methane is a product of the natural digestion of cows. Because the consumption of dairy products and meat is increasing mass husbandry is widely spread. Hence, the emission of methane attributed to cows rises to unnatural dimensions. Since most people are not willing to change their daily nutrition and reduce their consumption of several products significantly (see our survey) an elimination of methane emissions caused by cows would be useful. However, former approaches merely regard either the methanotrophs responsible for methane production or the substrates they need. Our project idea is to reduce global methane emission right at one of the sources, the rumen of cows, without affecting resident organisms. Our idea is to provide the digestive tract with a specially modified microorganism, named E. cowli, which is planned to metabolise the methane before its emission and, therefore, prevents the enhanced greenhouse effect and global warming.
Approach
The “Tag der Lehre” (translates to “Day of Teaching”) hosted by our university is dedicated to the appreciation of innovative teaching concepts and provides a platform for exchange about this topic. This is quite important to us because from our point of view synthetic biology is not yet appropriately represented in our curriculum. Therefore, we seized the opportunity and presented our iGEM team and project as a figurehead for synthetic biology at our university. In doing so, we made clear that it is an important subject with considerable significance not only from a scientific, but also from a societal perspective.
Our stand at the “Tag der Lehre” was visited by a variety of people from all kinds of professions and disciplines towards whom we could emphasize our concern. As some of them were university professors and even the principal was present, we think we might have come a little closer to our aim. The day ended with a science slam in which we presented our project in an entertaining way and actually won first prize - which we consider to be a positive sign for the future of synthetic biology at our university.
Results
In August we had a visitor in our lab for two weeks. Benjamin, a pupil from a local school, had decided to expand his knowledge on Synthetic Biology and Biotechnology. He proved to be very keen to learn new things and to become a valuable (albeit short-term) member of our team. Here is how he evaluates his stay with us:
“During the past two weeks I did an internship at the Institute for Biochemistry, Biotechnology and Bioinformatics of the TU Braunschweig. It was unique in several ways: I had the opportunity to look over the iGEM team members’ shoulders, to ask questions and I could even contribute to their project by carrying out some smaller tasks. These two weeks were eventful and exciting for me and I do not regret investing part of my holidays for them. I got a great insight into Biotechnology, especially the lab work.”
And although he may be a little too young for iGEM, he still acquired a taste for the idea behind the competition:
“Concerning iGEM, I am particularly fascinated by the fact that the project is in the students’ hands from start to finish and that they can get so much out of their contribution. Maybe I will also take this direction later and take part in the competition… Lots of luck to the Braunschweig iGEMers and I keep my fingers crossed for E. cowli to eventually be able to degrade methane. THANK YOU for the great internship!”
Potential Impact
Recent reports show that the public interest in vegan diets is on the rise [1]. Indeed, if more people forwent consuming beef and dairy products, methane emissions caused by livestock farming could be drastically reduced. In order to get further insight into the public’s willingness to change their diet for the sake of the climate we conducted a survey - before the revelation of our project, so that they would not be influenced. The exact question was: “Could you imagine changing your nutrition such that there are no more dairy or beef products on the menu to reduce the output of greenhouse gases?” The results are shown in the diagram at the left.
Even confronted with the possible consequences of their consume of dairy and beef products, most people were not willing to change their nutrition for a better climate. Additionally, it should be considered that clicking “Yes” in a survey is probably much easier than turning something into action for real, so in reality the “No” fraction would probably even more numerous. This implements that there should be another way of reducing the greenhouse gas emissions caused by livestock, and with our project we want to show how this could be achieved.
Engineering Principles
We also wanted to figure out what the public expects synthetic biology to contribute to society and in which areas that synthetic biology is applied in they wish the most for progress. Among these areas are medicine, renewable energy, environment, and nutrition. To those who were not familiar with the term “synthetic biology” we gave a short introduction, of course without influencing their opinion. The question was: “In which of the areas where synthetic biology is applied do you wish for progress?”
Apparently most people are interested in the use of synthetic biology for medicinal or environmental purposes, whereas less wanted synthetic biology to solve problems concerning renewable energy and the least wanted synthetic biology to interfere in nutritional issues. The results for nutrition and renewable energy were somewhat expected - genetically modified food is a hotly debated topic in Germany and renewable energy may be a somewhat intangible term, especially as the connection to synthetic biology is probably not as obvious as for the other areas.
On the other hand, we were quite surprised to find that people obviously cared about the environment as much as about medicinal issues. However, it would sure be interesting to see whether the age group has an influence on what the respective persons chose. Therefore, we also asked for the persons’ ages and got the following results.
Especially for environment and medicine it is interesting to see that persons younger than 40 years and persons of 40 years or older seem to form two distinct groups with equally distinct opinions. While the younger ones decided for environment more often, the opposite is the case for the older ones who are more interested in the use of synthetic biology for medicine. Although these differences might not be significant one can still assume that the age influences a person’s priorities. Preservation is a relatively new issue which might explain that younger ones seem to be more interested in it. This is probably not to the same degree the case for older people who instead wish for progress in more conventional areas like medicine, which also have a more direct influence on humans.
In general, however, there is a discrepancy of opinions. On the one hand, many people want to preserve the environment, but on the other hand, only few would be willing to change their diets in order to achieve this.
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