Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Charcoal: Major Missing Piece in the Global Carbon Cycle

10.07.2018

Most of the carbon resulting from wildfires and fossil fuel combustion is rapidly released into the atmosphere as carbon dioxide. Researchers at the University of Zurich have now shown that the leftover residue, so-called black carbon, can age for millennia on land and in rivers en route to the ocean, and thus constitutes a major long-term reservoir of organic carbon. The study adds a major missing piece to the puzzle of understanding the global carbon cycle.

Due to its widespread occurrence and tendency to linger in the environment, black carbon may be one of the keys in predicting and mitigating global climate change. In wildfires, typically one third of the burned organic carbon is retained as black carbon residues rather than emitted as greenhouse gases.


Rivers transport black carbon from land to sea.

Image: Gabriela Santilli, ETH Zürich


Global black carbon cycle in large reservoirs.

Figure: MELS/SIVIC, UZH

Initially, black carbon remains stored in the soil and in lakes, and is then eroded from river banks and transported to the ocean. However, black carbon is not taken into account in global carbon budget warming simulations, because its role in the global carbon cycle is not well understood as a result of a lack of knowledge about fluxes, stocks, and residence times in the environment.

First worldwide assessment of black carbon river transport

“Our study is the first to address the flux of black carbon in sediments by rivers on a global scale. We found that a surprisingly large amount of black carbon is exported by rivers,” says lead author Alysha Coppola, a postdoctoral researcher in the Department of Geography at the University of Zurich (UZH).

The study includes some of the largest rivers worldwide, such as the Amazon, Congo, Brahmaputra, and major Arctic rivers. It is the first global river assessment of the radiocarbon age values and amount of black carbon transported as particles. The researchers found that the more total river sediment is transported by rivers to the coast, the more black carbon travels with it and is ultimately buried in ocean sediments, forming an important long-term sink for atmospheric carbon dioxide.

Black carbon can age in intermediate reservoirs

To gain an overview of the processes occurring in the world’s rivers, the UZH researchers teamed up with colleagues from ETH Zurich, and the US-based Global Rivers Observatory at the Woods Hole Oceanographic Institution and the Woods Hole Research Center.

They discovered that the black carbon pathway from land to ocean is mainly shaped by erosion in river drainage basins. Surprisingly, they found that some black carbon can be stored for thousands of years before being exported to the ocean via rivers. This insight is new, since it was previously always assumed that after a fire, the remaining black carbon was quickly eroded by wind and water.

However, the authors found that black carbon does not always originate from recent wildfires, but could be up to 17,000 years old, particularly in the Arctic. “This explains the mystery as to why black carbon is continuously present in river waters, regardless of wildfire history. We found that black carbon can age in intermediate reservoirs that act as holding pools before being exported to the ocean,” says Alysha Coppola.

Literature:
Alysha I. Coppola, et. al. Global scale evidence for the refractory nature of riverine black carbon. Nature Geoscience. July 9, 2018. DOI: 10.1038/s41561-018-0159-8

Contact:
Alysha I. Coppola, PhD
Department of Geography
University of Zurich
Phone: +41 44 635 52 28
E-mail: alysha.coppola@geo.uzh.ch

Prof. Michael W.I. Schmidt, PhD
Department of Geography
University of Zurich
Phone: +41 44 635 51 40
E-mail: michael.schmidt@geo.uzh.ch

Rita Ziegler | Universität Zürich

More articles from Earth Sciences:

nachricht Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland
15.11.2018 | Faculty of Science - University of Copenhagen

nachricht The unintended consequences of dams and reservoirs
14.11.2018 | Uppsala University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>