"As an alternative to more established theories of global warming relating to levels of atmospheric carbon, a new research area considers that carbon levels in the atmosphere are most affected by the composition of the soil."
"Soil contains more carbon than air and plants combined. This would suggest that even a minor change in soil carbon could have major implications for the Earth's atmosphere and climate [debatable].
New research suggests that it is fungi that have a major influence on the carbon levels in soil and eventually the carbon levels in the atmosphere. By examining patterns of symbiotic fungi, researchers have shown that higher levels of fungi can lead to 70 percent more carbon in the soil. The role of these fungi is currently not typically considered in global climate models."
"The findings are not to suggest that the global warming debate is not an important one, but it does suggest that the Earth’s ecosystem is both complex and dynamic and that all aspects of the planet should be considered in relation to environmental stability or change."
Atmospheric carbon is mostly to do with the soil
As an alternative to more established theories of global warming relating to levels of atmospheric carbon, a new research area considers that carbon levels in the atmosphere are most affected by the composition of the soil.
Soil contains more carbon than air and plants combined. This would suggest that even a minor change in soil carbon could have major implications for the Earth's atmosphere and climate [the latter is debatable].
New research suggests that it is fungi that have a major influence on the carbon levels in soil and eventually the carbon levels in the atmosphere. By examining patterns of symbiotic fungi, researchers have shown that higher levels of fungi can lead to 70 percent more carbon in the soil. The role of these fungi is currently not typically considered in global climate models.
The role of soil fungi is important because the majority of plants link up with fungi, exchanging plant carbon for soil nutrients supplied by the fungus.
By examining over 200 soil profiles from around the globe, a research team found that soils supporting strong fungal-plant communities contained 70 percent more carbon per unit nitrogen than soils that did not.
The inference from the research is that any widespread shift in the species composition of forests could change the amount of carbon stored in soil, with consequences for atmospheric carbon dioxide concentrations.
The findings are not to suggest that the global warming debate is not an important one, but it does suggest that the Earth’s ecosystem is both complex and dynamic and that all aspects of the planet should be considered in relation to environmental stability or change.
The study was led by Smithsonian Tropical Research Institute scientist Benjamin Turner. The findings have been published in the journal Nature. The paper is titled “Mycorrhiza-mediated competition between plants and decomposers drives soil carbon storage.”
Read more: http://www.digitaljournal.com/tech/science/atmospheric-carbon-is-mostly-to-do-with-the-soil/article/365469#ixzz2qIWQ83WG
Mycorrhiza-mediated competition between plants and decomposers drives soil carbon storage
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- Nature
- doi:10.1038/nature12901
- Received
- Accepted
- Published online
Soil contains more carbon than the atmosphere and vegetation combined1. Understanding the mechanisms controlling the accumulation and stability of soil carbon is critical to predicting the Earth’s future climate2, 3. Recent studies suggest that decomposition of soil organic matter is often limited by nitrogen availability to microbes4, 5, 6 and that plants, via their fungal symbionts, compete directly with free-living decomposers for nitrogen6, 7. Ectomycorrhizal and ericoid mycorrhizal (EEM) fungi produce nitrogen-degrading enzymes, allowing them greater access to organic nitrogen sources than arbuscular mycorrhizal (AM) fungi8, 9, 10. This leads to the theoretical prediction that soil carbon storage is greater in ecosystems dominated by EEM fungi than in those dominated by AM fungi11. Using global data sets, we show that soil in ecosystems dominated by EEM-associated plants contains 70% more carbon per unit nitrogen than soil in ecosystems dominated by AM-associated plants. The effect of mycorrhizal type on soil carbon is independent of, and of far larger consequence than, the effects of net primary production, temperature, precipitation and soil clay content. Hence the effect of mycorrhizal type on soil carbon content holds at the global scale. This finding links the functional traits of mycorrhizal fungi to carbon storage at ecosystem-to-global scales, suggesting that plant–decomposer competition for nutrients exerts a fundamental control over the terrestrial carbon cycle.
Why Some Mushrooms May Be Magic for Climate Change
The soil contains more carbon than all living plants and the atmosphere combined. Now a new study says that a certain type of fungi can help soil hold up to 70% more carbon—with potentially big impacts for the climate
By serial misinformer Bryan Walsh @bryanrwalsh TIME Jan. 08, 2014
Fungi don’t get the respect they deserve. Maybe that’s because they do most of their work in the dark, beneath the ground or on dead matter, or because there’s something essentially alien and bacterial about their appearance and the way they grow. But fungi are so plentiful and basic to life that they’re recognized as their own phylogenic kingdom. There may be more than 5 million separate species of fungi, and the largest single organism on the planet is a fungus: the four sq. mi. (10 sq. km) Armillaria ostoya fungus, which lives in the soil of Oregon’s Blue Mountains and which may be more than 8,000 yeas old. Without fungi we wouldn’t have antibiotics, blue cheeses and most importantly, beer. And we won’t even get into the magic kind.
Fungi also play an important role in the carbon cycle, the biogeochemical process by which carbon—the essential element of life on Earth—moves between the air, soils and water. Plants sequester carbon dioxide, but when they die, that carbon enters the soil—a lot of it. Globally, soil is the biggest single terrestrial reservoir of carbon, far more than the amount of carbon contained in living things and in the atmosphere combined. (On a planetary scale, the oceans hold by far the most carbon.) As the dead plant matter is broken down by microbes in the oil, that carbon is released back into the air. The rate at which that carbon leaves the soil can obviously have a major impact on the amount of carbon in the atmosphere, which in turn helps drive climate change.
One of the limits to the growth of those decomposing microbes is the availability of nitrogen in the soil. Living plants and soil microbes compete for nitrogen, and the less nitrogen is available to the microbes, the slower decomposition is—and the more carbon remains in the soil, instead of outgassing into the atmosphere. This is where the fungi come in. Most plants have a symbiotic relationship with mycorrhizal fungi: the fungi extract the nitrogen from the soil, and make it available to the plants through their roots. But according to a new study in Nature, one major type of the symbiotic fungi can extract nitrogen much more quickly than other types—and that in turn slows the growth of the competing microbes and leaves much more carbon locked away in the soil.
Researchers from the University of Texas, Boston University and the Smithsonian Tropical Research Institute ran computer models on data from more than 200 soil profiles from around the world. They found that soils dominated by ecto- and ericoid mycorrhizal (EEM) fungi contain as much as 70% more carbon than soils dominated by arbuscular mycorrhizal (AM) fungi. That’s because the EEM fungi produce more nitrogen-degrading enzymes, which allows them to extract more nitrogen from the soil. They essentially outcompete the soil microbes, which slows down their ability to decompose dead plant matter and return carbon from the soil to the atmosphere. “This analysis clearly establishes that the different types of symbiotic fungi that colonize plant roots exert major control on the global carbon cycle, which has not been fully appreciated or demonstrated until now,” said Colin Averill, a graduate student at the University of Texas and the lead author of the paper.
That relationship between the different types of fungi and plants is so important for the carbon cycle because it’s independent of temperature, precipitation, soil clay content and all the other variable factors that can influence plant growth and soil content. Perhaps unfortunately for us, though, AM fungi symbiosis is far more common, occurring in approximately 85% of plant families, while just a few plant families have a symbiotic relationship with EEM fungi. That could change as the composition of forests change, however, but we wouldn’t know the effects until scientists add the role of the different kinds of symbiotic fungi into global climate models, which they have yet to do.
“This study shows that trees and decomposers are really connected via these mycorrhizal fungi, and that you can’t accurately predict future carbon cycling without thinking about how these two groups interact,” said Averill. “We need to think of these systems holistically.” The humble fungus won’t be forgotten.
Read more: Study Shows That Some Fungi Help Soils Keep More Carbon Out of the Air | TIME.com http://science.time.com/2014/01/08/why-some-mushrooms-may-be-magic-for-climate-change/#ixzz2qIe93JGs
http://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2F2014JG002703
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