April 20, 2013
Charcoal From Wildfires Enters Waterways And Works Its Way To Oceans
redOrbit Staff & Wire Reports - Your Universe Online
New research claims charcoal created from wildfires does not remain in the soil as previously believed, but is instead transported into the sea by rivers, where it ultimately enters the carbon cycle.That determination was made by an international team of researchers, including Thorsten Dittmar from the Max Planck Institute for Marine Microbiology (MPI) in Bremen and Rudolf JaffÃ© from Florida International University's Southeast Environmental Research Center (SERC) in Miami.
Dittmar, JaffÃ© and their colleagues analyzed water samples from all across the world, and demonstrated soluble charcoal accounted for 10 percent of the total amount of dissolved organic carbon.
“Most scientists thought charcoal was resistant. They thought, once it is incorporated into the soils, it would stay there, but if that were the case, the soils would be black,” JaffÃ© said in a statement Friday. “From a chemical perspective, no one really thought it dissolves, but it does. It doesn´t accumulate like we had for a long time believed. Rather, it is transported into wetlands and rivers, eventually making its way to the oceans.”
The research team, which also included experts from Skidaway Institute of Oceanography in Georgia, Woods Hole Research Center in Massachusetts, the USDA Forest Service and the University of Helsinki in Finland, obtained a total of 174 water samples from the Amazon, Congo and Yangtze rivers, as well as Arctic locations and other global bodies of water.
They found any river, regardless of its location, contained about 10 percent of organic carbon that was dissolved in the water and originated from charcoal. Based on those findings and previous scientific studies of organic carbon flux, Dittmar, JaffÃ© and their colleagues estimate approximately 25 million tons of dissolved charcoal is transported from the land to the sea each year.
These results can help scientists improve their calculations of global carbon budget, the researchers said. Producing detailed calculations of the sources which produce carbon and the sinks that remove it are essential to providing accurate assessments of climatic effects, as well as finding ways to alleviate related issues that arise.
Prior to this research, scientists were only able to provide rough estimates of the amount of charcoal in the soil, and according to the authors of the current study, most of those estimates turned out to be incorrect. Their findings suggest more attention needs to be given to carbon sequestration techniques — methods of capturing and storing atmospheric carbon dioxide for long periods of time.
JaffÃ© and Dittmar said they plan to continue their work, and they hope to determine how the charcoal reaches the sea and what consequences the phenomenon has on the environment. In the meantime, their current study, “Global Charcoal Mobilization from Soils via Dissolution and Riverine Transport to the Oceans,” was published Friday in the journal Science.