Large Quantity of Charcoal Deposited in Oceans Each Year

Charcoal from wildfires doesn't remain in the soil, but is transported to oceans where it enters the global carbon cycle, according to a new study. This water soluble carbon makes up for a tenth of organic carbon in water bodies, researchers found.

The study was conducted by a team of researchers led by Thorsten Dittgar from the Max Planck Institute for Marine Microbiology in Bremen, and Rudolf Jaffé from Florida International University's Southeast Environmental Research Center in Miami. The study estimates that about 25 million tons of charcoal is transported to the oceans each year.

Understanding how charcoal is transported to oceans can help researchers better calculate the global carbon budget.

"Most scientists thought charcoal was resistant. They thought, once it is incorporated into the soils, it would stay there," said Jaffé. "But if that were the case, the soils would be black."

"From a chemical perspective, no one really thought it dissolves, but it does," Jaffé said in a news release. "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."

For the study, researchers collected 174 water samples from different regions of the world, such as the Amazon, the Congo, the Yangtze and Arctic sites.

Researchers found that in almost all rivers, 10 percent of organic carbon dissolved in water came from charcoal. Based on data obtained from the study along with models that stimulate the global influx of carbon from charcoal in water, researchers estimate that 25 million tons of charcoal goes into the world's oceans each year.

The study results will help refine calculations of the global carbon budget - a balancing act between carbon emission sources and sinks that remove carbon from the atmosphere.

Researchers said that the study results show that carbon sequestration techniques such as storing carbon in the soil must be given more consideration. Another carbon sequestration technique is biochar addition to soils, where vegetation-derived charcoal is used to store carbon in the soil. Although the technique is good, researchers say that people must know that a lot of this charcoal can end up in the ocean.

The U.S. had a particularly bad wildfire season last year, with nearly 7 million acres burning by the end of August 2012. According to a study, wildfires in the future might be stronger and more long-lasting than current wildfires.