Past analyses of carbon and greenhouse gas exchanges on continents have failed to account for the influence of lakes, impoundments, and running water. This study, published in the journal Science, shows that natural release of the potent greenhouse gas methane from inland waters may be far greater than previously known. By difference, the net absorption of greenhouse gases by natural land environments, such as forests, may therefore be at least 25 % smaller than thought.
This is the conclusion of a study by David Bastviken, Linköping University, Lars Tranvik, Uppsala University, John Downing, Iowa State University, Patrick Crill, Stockholm University, and Alex Enrich-Prast, University Federal of Rio de Janeiro.
The increased greenhouse effect is caused by human emissions of greenhouse gases. Some ecosystems, such as forests can absorb carbon dioxide and act as greenhouse gas sinks, which is important for the greenhouse gas balance and the climate. The role of freshwater environments, integrated into continental environments, has been unclear because of underestimates of the amount of continental water and a shortage of data on greenhouse gas emissions.
Methane emissions from lakes and running water occur naturally and should not be considered an environmental threat. These gas emissions have, however, been difficult to assess and are poorly understood.
- Small methane emissions from the surfaces of water bodies occur continuously, says David Bastviken, but much greater emissions occur suddenly, and with irregular timing, when methane bubbles from the sediment reach the atmosphere. Such fluxes have been difficult to measure.
The authors have summarized methane fluxes from 474 freshwater environments. They have also used updated estimates of the global area of inland waters. Based on these data, they estimated that methane emissions from the freshwaters of the world counter-balance 25 percent of the carbon dioxide absorbed by natural land environments. The large effect of aquatic methane emission is due to the large quantity of gas emission and the stronger greenhouse effect produced by methane molecules compared to carbon dioxide. One implication of this new accounting is that the greenhouse gas sink provided by forests and other land ecosystems is substantially smaller than hitherto believed.
The terrestrial sink may even be lower than we have calculated, says David Bastviken. Because it is difficult to measure methane bubble fluxes and the global area of freshwaters may still be underestimated, we have probably underestimated the methane emissions.If we do not properly account for natural greenhouse gas sinks and emissions, we may misunderstand the urgency of reducing anthropogenic emissions.
A smaller continental greenhouse gas sink means that the capacity of natural systems to absorb greenhouse gases is very valuable.
- We have to take great care of the remaining forests and other natural greenhouse gas sinks, because we have already reduced their area through deforestation and other land conversions, David says. An accurate accounting of all components of the continental greenhouse gas budget, including the role of inland waters, will help us evaluate the greenhouse gas uptake by land ecosystems in relation to society’s greenhouse gas emissions.Freshwater Methane Emissions Offset the Continental Carbon Sink
Åke Hjelm | idw
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Information Technology
23.11.2017 | Physics and Astronomy
23.11.2017 | Life Sciences