Featured Research

from universities, journals, and other organizations

A balanced carbon footprint for the Amazon River

Date:
April 4, 2014
Source:
Institut de Recherche pour le Développement (IRD)
Summary:
Considered, until now, a source of greenhouse gas emissions, capturing the CO2 fixed by the tropical forest through the soils of the watershed to release it into the atmosphere, the Amazon River actually has a balanced carbon footprint. In fact, a new study shows that the CO2 outgassed by the river is only drawn from the river system itself, by the semi-aquatic vegetation on the flood plains. Therefore, the Amazon recycles the CO2 from its own river system, and not that fixed by the tropical forest, releasing as much carbon dioxide into the atmosphere as it absorbs.

The Amazon.
Credit: © IRD / J-M Martinez

Considered, until now, a source of greenhouse gas emissions, capturing the CO2 fixed by the tropical forest through the soils of the watershed to release it into the atmosphere, the Amazon River actually has a balanced carbon footprint. In fact, a new study shows that the CO2 outgassed by the river is only drawn from the river system itself, by the semi-aquatic vegetation on the flood plains. Therefore, the Amazon recycles the CO2 from its own river system, and not that fixed by the tropical forest, releasing as much carbon dioxide into the atmosphere as it absorbs. This study, coordinated by researchers from the GET (IRD, OMP, CNRS, CNES, UPS) and EPOC laboratories (OASU, CNRS, Université Bordeaux 1) and published in the journal Nature, changes the order for global carbon footprints.

Related Articles


The Amazon recycles its own CO2

The study contributes a new conception of the carbon cycle in the Amazon, and more generally on the continents. Until now, researchers thought that rivers were supplied with carbon by trees and other land plants through the soils of the watershed. This carbon was then transformed into CO2 and released by outgassing into the atmosphere. Watercourses, and in particular the giant Amazon, were thus considered as net sources of emissions, releasing more CO2 than they absorbed. Now, researchers have just shown that the CO2 outgassed by the waters of the Amazon is in reality only drawn from the river system itself. This CO2 comes from the decomposition of the organic matter produced by semi-aquatic vegetation in the Amazon wetlands. Conversely to what we thought, the river thus acts as a "CO2 pump."

The link between aquatic vegetation and CO2emission

Ten French and Brazilian teams within the framework of the ANR-CARBAMA project and the HYBAM environmental research observatory conducted many field-studies in the Amazon region and analysed satellite images. The measurements of CO2 concentrations dissolved in the water compared to the satellite map of vegetation showed a very strong correlation between the intensity of CO2 outgassing and the area of flooded vegetation and floating aquatic plants. This proportional relationship can be verified at two levels: over time, as the water level varies during the year; and in space, as the proportion of vegetation diminishes from upstream of the study area, where flooded forests dominate, to downstream, where the majority of the lakes are found.

All emissions covered by the wetlands

The Amazon emits some 200,000 tons of carbon per year through outgassing. According to the researcher's estimates, the majority of these emissions come from the respiration of the roots and the fall and decay of the semi-aquatic vegetation in the flood plains. In fact, the researchers showed a very high export ratio toward the aquatic environment of the gross primary production of the Amazon wetlands: half of this carbon, in the form of dissolved CO2 and biodegradable organic matter, is transferred directly to the river. This quantity of CO2 is equivalent to the 200,000 tons of carbon outgassed annually. Therefore, the carbon footprint of the river system in the central Amazon region is close to equilibrium: its waters release the same quantity of carbon into the atmosphere as is fixed by its vegetation.

Nevertheless, this study highlights the very heavy contribution of inland waters to CO2 emissions. It sheds light on the need to consider the specific properties of wetlands in global carbon footprints.


Story Source:

The above story is based on materials provided by Institut de Recherche pour le Développement (IRD). Note: Materials may be edited for content and length.


Journal Reference:

  1. Gwenaël Abril, Jean-Michel Martinez, L. Felipe Artigas, Patricia Moreira-Turcq, Marc F. Benedetti, Luciana Vidal, Tarik Meziane, Jung-Hyun Kim, Marcelo C. Bernardes, Nicolas Savoye, Jonathan Deborde, Edivaldo Lima Souza, Patrick Albéric, Marcelo F. Landim de Souza, Fabio Roland. Amazon River carbon dioxide outgassing fuelled by wetlands. Nature, 2013; 505 (7483): 395 DOI: 10.1038/nature12797

Cite This Page:

Institut de Recherche pour le Développement (IRD). "A balanced carbon footprint for the Amazon River." ScienceDaily. ScienceDaily, 4 April 2014. <www.sciencedaily.com/releases/2014/04/140404085643.htm>.
Institut de Recherche pour le Développement (IRD). (2014, April 4). A balanced carbon footprint for the Amazon River. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2014/04/140404085643.htm
Institut de Recherche pour le Développement (IRD). "A balanced carbon footprint for the Amazon River." ScienceDaily. www.sciencedaily.com/releases/2014/04/140404085643.htm (accessed October 25, 2014).

Share This



More Earth & Climate News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) — EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) — Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) — A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) — Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins