Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Greenhouse gas emissions from freshwater higher than thought

16.12.2015

Do not underestimate the babbling brook. When it comes to greenhouse gases, these bucolic water bodies have the potential to create a lot of hot air.

According to a new analysis in the journal Ecological Monographs, by researchers at the University of Wisconsin-Madison and colleagues, the world's rivers and streams pump about 10 times more methane into our atmosphere than scientists estimated in previous studies. The new study also found that human activity seems to drive which streams are the biggest contributors.


Nick Gubbins, an undergraduate student who has worked in the Stanley lab, takes methane flux measurements in the field.

Credit: Luke Loken, UW-Madison Center for Limnology

"Scientists know that inland waters, like lakes and reservoirs, are big sources of methane," says Emily Stanley, a professor at the UW-Madison Center for Limnology and lead author of the paper. Yet accurately measuring emissions of methane from these sources has remained a challenge.

Like carbon dioxide, methane is a greenhouse gas that traps heat at the Earth's surface. It is less prevalent than carbon dioxide in the atmosphere but also more potent: A molecule of methane results in more warming than a molecule of carbon dioxide. Understanding how much methane is emitted into the atmosphere from all sources helps scientists account for the full global greenhouse gas budget, and take measures to mitigate its impact.

Rivers and streams haven't received much attention in accounting for that budget, Stanley says, because they don't take up much surface area on a global scale and, with respect to methane, didn't seem to be all that gassy. But over the years, measurements taken by Stanley and her lab members seemed to indicate these sources may produce more methane than scientists had previously known.

Together with other center researchers and scientists at the University of Winnipeg and the U.S. Geological Survey's LandCarbon Project, the team created a database of measured methane flux (the exchange of the gas between water and atmosphere) and methane concentrations measured in streams and rivers using data from 111 publications and three unpublished datasets.

The research team then used two different methods to calculate the best estimates of global methane emissions from the data. They found the emissions to be an order of magnitude higher than scientists had previously reported.

The result was "very surprising," Stanley says. "I thought maybe we'd be off by a factor of two, so I was taken aback by how much higher the estimate was."

The researchers pointed to one possible reason: Not every stream is identical. The analysis revealed noticeably higher methane emissions from streams and rivers in watersheds marked with heavy agriculture, urban development or the presence of dams. This suggests efforts to improve stream health may have the added benefit of reducing greenhouse gases.

"The fact that human activity in a watershed leads to high methane concentrations in those rivers and streams underscores yet another reason to pay attention to water quality," says Stanley. "On top of everything else, it adds to this climate problem, too."

Methane from freshwater is often a byproduct of bacterial metabolism, as they break down organic matter under low-oxygen conditions, like in the sediment at the bottom of a lake. As the climate warms, the contribution of greenhouse gases from natural sources likes rivers, streams and wetlands is expected to increase because higher temperatures accelerate this bacterial breakdown, releasing more carbon dioxide and methane.

The next step, says Stanley, is figuring out where all that methane comes from. Running rivers and streams are usually better aerated and full of oxygen, making all that methane a bit of a mystery. Is it coming from groundwater? Somewhere along a riverbank? At the bottom of the stream itself? For now, the babbling brook is keeping that information to itself.

###

Adam Hinterthuer (608) 890-2187, hinterthuer@wisc.edu

Media Contact

Emily Stanley
ehstanley@wisc.edu
608-213-3715

 @UWMadScience

http://www.wisc.edu 

Emily Stanley | EurekAlert!

More articles from Earth Sciences:

nachricht Der steile Aufstieg der Berner Alpen
24.03.2017 | Universität Bern

nachricht Steep rise of the Bernese Alps
24.03.2017 | Universität Bern

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>