Overgrowth Of The Arctic With Southern Plants May Lead To Increased Greenhouse Gas Emissions
Climate scientists have found that the penetration of southern plants into the Arctic can almost double the annual greenhouse gas emissions that occur as a result of the decomposition of ancient organic matter in thawed soil. A description of their research is available in the scientific journal Nature Geoscience.
"We have known for half a century that plant roots stimulate the reproduction of microbes that decompose soil organic matter by feeding them sugar. On the other hand, until now, we have not had any information about how these interactions between flora and microflora will affect the carbon cycle in nature," said Frida Kuiper, a climatologist at umeå University (Sweden) and one of the authors of the paper.
As scientists suggest, the rapid warming of the Arctic as a result of global climate change will lead to a sharp reduction in the area of permafrost that arose in the soil of the Northern regions of Eurasia and North America during the last glaciation. Climate scientists believe that about a third of the permafrost located in southern Siberia and Alaska will disappear by the end of this century.
This process will release a huge amount of frozen organic matter that has been accumulating in the frozen soil for several hundred thousand years. These remains of flora and fauna are quickly decomposed by microbes, which will lead to the release of large amounts of methane and carbon dioxide. Similarly, the draining of the Arctic associated with the melting of permafrost will lead to more frequent wildfires, which will also destroy these organic reserves.
Kuiper and her colleagues, including Russian researchers from the forest Institute of the SIBERIAN branch of the Russian Academy of Sciences in Krasnoyarsk, tested how these emissions will be affected by so-called "priming," a special soil process related to how plant roots interact with the surrounding soil microflora.
The roots of global warming
The fact is that scientists in the middle of the last century discovered that all representatives of the flora with a developed root system directly "conduct" the life of many soil fungi, bacteria, and even multicellular animals, releasing sugars and various volatile substances.
By establishing a symbiotic relationship with them, plants gain access to new sources of water and nutrients, while their "partners" are able to feed on the dying cells of the outer shell of the roots and get carbohydrates that the ground part of the plant produces. All this, in particular, leads to the fact that the decomposition of soil organic matter is rapidly accelerated, and this effect can be achieved if you simply enter the soil extract of the roots of the plant.
Climatologists from Russia, Europe, and the United States wondered how much such interactions between flora and soil microflora will affect the decomposition of organic matter that has recently melted together with permafrost. To do this, scientists compared the length of the root system of plants from the tundra and temperate forests and then estimated how much organic matter would decompose both plants.
These calculations showed that overgrowth of the Arctic and circumpolar regions with plants with a developed root system would lead to a sharp increase in greenhouse gas emissions. In total, soil bacteria will additionally emit approximately 400 million tons of greenhouse gases each year, which will actually double the total amount of emissions associated with thawed permafrost.
Especially strongly, as the researchers note, these processes will affect the Eastern part of Western Siberia, the Taimyr Peninsula, as well as many Northern regions of Eastern Siberia and the Central regions of Canada. Given the huge amounts of greenhouse gases that will be generated by bacteria and plants, their existence must be taken into account when predicting the Earth's climate and evaluating the effectiveness of measures to combat global warming, climatologists conclude.