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Tropical soil disturbances can be a hidden source of CO2



  Tropical soil disturbances could be a hidden source of CO2.
Tropical areas like the Congo are experiencing widespread deforestation and land conversion for agriculture. Picture credits: Rob Spencer

According to a recent study by Florida State University researchers, thousand-year-old tropical soils exposed by accelerating deforestation and land use in agriculture could release carbon dioxide into the atmosphere.

Investigating 1

9 sites in the eastern Democratic Republic of the Congo, researchers found that heavily deforested areas leach organic carbon that is much older and more biodegradable than organic carbon leached from densely forested areas.

Soil horizons released from deeper regions and older, chemically unstable organic carbon leached by water into rivers are finally consumed by streaming microbes that devour the rich compounds and release carbon dioxide back into the atmosphere. It is a process that could endanger local ecosystems and fuel the greenhouse effect, according to researcher study author Rob Spencer, associate professor at the FSU's Institute of Earth, Ocean and Atmospheric Sciences. "The Congo is now facing the transformation of untouched land into agriculture, and we want to know what that could mean for the carbon cycle."

Although the more general effects of deforestation on the carbon cycle are known, the researchers announced their published findings today in the journal Nature Geoscience suggest that there is an additional pathway or additional carbon shift in Rivers of soil that was churned by deforestation and land conversion.

"At this point, it's hard to know how big that is." The river and thus the relative importance of this process compared to other anthropogenic CO2 sources is likely to increase with additional deforestation and land use conversion, "said the former postdoctoral researcher FSU, Travis Drake, lead author of the study, "We hope this essay encourages more research into the relative importance of this process."

To better distinguish the different soils in their study, researchers analyzed dissolved organic carbon, the Using high-resolution mass spectrometry data generated with state-of-the-art National High Magnetic Field Laboratory (FSU) tools, the team found that the older dissolved organic matter released from deforested areas was discharged from the study areas into effluent streams and rivers were, more energetic and chemically vielfäl tiger than those from better preserved forests

  Tropical Soil Disruptions Could Be Hidden CO2 Source
Tropical areas like the Congo are exposed to widespread deforestation and land use conversion for agriculture. Photo credit: Florida State University

Overall, wooded areas released significantly more dissolved organic carbon than deforested areas. But the dissolved organic substances that came from deforested and land-converted regions were exceptionally biologically or microbially-susceptible.

"The dissolved organic substances from deforested landscapes were compositionally full of things that microbes prefer – simple and easily accessible compounds with lots of nitrogen," said Drake, who is now researching at the Swiss Federal Institute of Technology in Zurich. "We believe that the microbial consumption of these ancient organic substances from the soil may in part explain the higher levels of CO2 that we have observed in the streams of the deforested areas." Increases the leaching of organic carbon by precipitation drastically. This loss of organic matter could affect soil fertility and reduce the downstream transport of critical nutrients that support aquatic and coastal ecosystems.

In a broader sense, this process means that carbon, which has been securely bound on earth for millennia, can now re-enter the environment. Modern carbon cycle. If, as researchers suspect, this carbon is eventually released into the atmosphere as carbon dioxide, it could contribute to the greenhouse effect. The researchers said these findings underscore the urgency to identify the effects of deforestation and second- and third-order soil transformation and the uncontrolled disruption of deeper, nutrient-rich soils in the tropics. While widespread and systematic forest conservation is the best antidote, the publication suggests that less disruptive agricultural practices could help offset some of the destabilization.

Use the transformation, "said Spencer.

" Ultimately, it's important to conserve forests that store and sustain carbon in soils for extended periods of time, "added Drake." Land use conversions can lead to better practices such as terracing, use of buffer strips and application of organic residues improve some of the observed organic carbon leaching. "


Old permafrost quickly converts to carbon dioxide during thawing


Further information:
Mobilization of aged and biolabile soil carbon through deforestation of tropical forests, Nature Geoscience (2019). DOI: 10.1038 / s41561-019-0384-9, https://www.nature.com/articles/s41561-019-0384-9

Provided by
Florida State University




Quote :
Tropical Soil Disruption May Be Hidden CO2 Source (2019, June 24)
retrieved on June 24, 2019
from https://phys.org/news/2019-06-tropical-soil-disturbance-hidden-source.html

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