Microbes play a vital role in reducing air pollution and global warming. Let us have a glimpse at the role of microbes in carbon sequestration and in climate change.
Microbes are microscopic living things found in water, soil, the air and our bodies. Microbes are also referred to as microorganisms and some of them are disease causing agents while others are helpful to the body as well as the environment. The microbes include bacteria, viruses and fungi and they are part of our life and environment.
It is a well-known fact that human body contains numerous microbes and every microorganism is not harmful to us. For example, human intestine contains probiotic bacteriae and vitamin K synthesizing bacteriae which helps to maintain the gut health. Similarly, our environment also incorporates microbes as a part of our ecosystem and which helps to maintain ecological balance.
Melbourne researchers have discovered that microbes of our environment consume huge amounts of atmospheric carbon monoxide (CO) and helps in detoxification process. CO is a green house gas which leads to global warming phenomenon due to their increased heat trapping potential.
The Monash University-led Study, published in Nature Chemical Biology, shows that at an atomic level how microbes consume carbon monoxide present in the atmosphere. The microbes use a special enzyme, called the CO dehydrogenase in this detoxification process. These microbes consume CO for their own survival, but it helps to clear carbon monoxide, the toxic gas that gets trapped on Earth’s atmosphere.
Microbes reduce air pollution
Carbon monoxide [CO] is an atmospheric trace gas and rarely exceeds 1 ppm except in heavily polluted city airspaces, volcanic exhalations, or industrial flue gases . Volcanic exhalations have significant CO content, submarine hydrothermal vent fluids have about 100 nM CO .
Moderate concentrations of CO are produced by bacterial fermentation or in soil associated with rhizosphere bacteria. CO has high potential as an electron donor, and represents a very favorable energy and carbon source for microbial growth. Some atmospheric microbes utilize atmospheric carbon monoxide as a part of their survival process, but this detoxification process by the microbes has positive impact on our ecosystem as it reduces air pollution, which kills many millions of people each year.
Microbes impact global warming
According to NASA, Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period (between 1850 and 1900) due to human activities , primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere. Since the pre-industrial period, human activities are estimated to have increased Earth’s global average temperature by about 1 degree Celsius (1.8 degrees Fahrenheit), a number that is currently increasing by more than 0.2 degrees Celsius (0.36 degrees Fahrenheit) per decade.
Generally, life on Earth depends on energy coming from the Sun. About half the light energy reaching Earth’s atmosphere passes through the air and clouds to the surface, where it is absorbed and radiated in the form of infrared heat. About 90% of this heat is then absorbed by greenhouse gases and re-radiated, slowing heat loss to space. Greenhouse gases are slowing heat loss from the lower atmosphere.
The consumption of carbon monoxide [CO]by the microbes help to reduce global warming, as CO is a notoriously known for raising atmospheric temperature as a greenhouse gas. Five key greenhouse gases are carbon dioxide, nitrous oxide, methane, chlorofluorocarbons, and water vapor.
History of link between microbes and environment
The evidence for CO utilization by “methane bacteria” was noted by Kluyver and Schnellen in 1947 and since then many microbes using CO via oxidation have emerged. Many strains of microbes use molecular oxygen as the electron acceptor for aerobic oxidation of CO.
Carbon monoxide (CO) is one of the most important chemical reactants in the troposphere layer of earth’s atmosphere. It influences the fate of methane and ozone by removing the major atmospheric oxidizing agent, hydroxyl radical.
Fossil fuel use, biomass burning, and oxidation of atmospheric hydrocarbons (methane and other compounds) account for most of the CO source strength of the atmosphere.
Carbon dioxide sequestration
Soil microbes are essential to carbon sequestration. Certain bacteria and algae convert carbon dioxide into organic matter, which is then stored in the soil. This helps remove excess carbon dioxide from the atmosphere, mitigating the effects of global warming.
Some of the key soil microbes involved in carbon sequestration include:
Mycorrhizal fungi: These fungi form mutualistic relationships with plant roots, helping plants to absorb nutrients and water from the soil. They also play a role in carbon sequestration by increasing the amount of carbon stored in the soil.
Actinobacteria: These bacteria are known to decompose plant litter and other organic matter, releasing carbon dioxide in the process. They also play a role in carbon sequestration by producing organic compounds that help to stabilize soil organic matter.
Rhizobia: These bacteria form symbiotic relationships with legume plants, fixing nitrogen from the air and making it available to the plant. This process also helps to increase the amount of carbon stored in the soil.
Arbuscular mycorrhizal fungi: These fungi form symbiotic relationships with a many plant species, and they play vital role in carbon sequestration by increasing the amount of carbon stored in the soil.
Proteobacteria: These bacteria help in decomposing plant litter and other organic matter, releasing carbon dioxide. However, they aid carbon sequestration by producing compounds that help to stabilize soil organic matter.
Scientists have recently discovered a microbe, a type of cyanobacteria, off the coast of a volcanic island near Sicily that consumes carbon dioxide (CO2) very quickly. Cyanobacteria are a type of bacteria that use photosynthesis to obtain energy, capturing carbon in the process.
Together with a team of researchers from Harvard and Cornell universities in the US and the University of Palermo in Sicily, and with help from the Vulcano community, Tierney isolated a microbe that converted CO2 into biomass faster than other known cyanobacteria.
How do microbes impact climate change?
Scientists all over the world are of the opinion that tackling climate change will require large-scale carbon capture and carbon sequestration. Both aims at removing excess carbon dioxide from the atmosphere and thus prevent the climate change. This can probably be achieved via new technology or through protecting and enhancing existing natural ecosystems such as forests, peatlands and soils.
Last year the UN’s Intergovernmental Panel on Climate Change (IPCC) said that carbon capture is essential because even big cuts to emissions won’t be enough to limit global warming. Microbes play a crucial role in caron capture.
This discovery elucidates the significance of coexistence of microbes in our environment for better weather and climatic state. All microbes are not deleterious to our health in normal weather and climatic conditions. Some are helpful in preserving the equilibrium of our ecosystem.
written by
Dr. Sanjana.p. Souparnika
References for further reading
- https://www.monash.edu/news/articles/study-reveals-how-microbes-help-detoxify-our-atmosphere#:~:text=Over%20two%20billion%20tonnes%20of,reducing%20CO%20to%20safer%20levels.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6317499/
- https://science.nasa.gov/climate-change/what-is-climate-change/#:~:text=Global%20warming%20is%20the%20long,gas%20levels%20in%20Earth’s%20atmosphere.
- https://biomemakers.com/blog/6-ways-microbes-fight-climate-change
- https://www.bbc.com/future/article/20230829-the-bacteria-that-can-capture-carbon
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