Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Drop in acid rain altering Appalachian stream water

14.12.2006
Appalachian hardwood forests may be getting a respite from acid rain but data from a long-term ecological study of stream chemistry suggests that the drop in acid rain may be changing biological activity in the ecosystem and hiking dissolved carbon dioxide in forest streams.

"These are unexpected results," says David DeWalle, professor of forest hydrology at Penn State. "Rising amounts of carbon dioxide in streams and soil could have implications for the forest ecosystem, and the carbon balance in general."

DeWalle and his colleagues have been monitoring stream water chemistry in the Appalachians since 1990. They are studying the effect of reduced sulfur emissions – required under the Clean Air Act – on the water quality of five streams in Pennsylvania.

"These streams are as pristine as you can get, and we have been sampling them nearly every month over the past 15 years," he says.

Some expected changes in stream chemistry are already showing. Water quality in the streams is gradually improving from the reduced sulfur emissions, and researchers are also seeing less nitrogen from the atmosphere and in the streams.

"This reduction in nitrogen deposition is yet to be seen in many parts of New England," DeWalle says. "We are probably seeing it earlier than others because we are pretty close to the sources of these emissions."

There have also been some unexpected changes. DeWalle and his Penn State colleagues Bryan Swistock, extension specialist, and Anthony Buda and Sarah MacDougall, graduate students, say they are recording rising amounts of dissolved carbon dioxide in all five streams.

DeWalle, whose work is funded by the U.S. Environmental Protection Agency, thinks that by reducing pollutants emitted to the atmosphere, we are creating a different set of conditions for organisms in the soil. The rising dissolved carbon dioxide in the streams, he suggests, might be traced to increased respiration by these organisms.

He explains that organic matter broken down by these organisms generates byproducts such as carbon dioxide, water and residual dissolved organic matter. The increased respiration, he adds, may be gradually increasing soil carbon dioxide and reducing the amount of residual organic matter. As the organisms break down more of the organic matter, there is less of it leaving as dissolved organic matter in stream water.

"There have been some experiments where they added nitrogen to the soil and saw a reduction in soil respiration. We have of course, reduced the nitrogen, and indicators of stream chemistry suggest that this may have caused the opposite reaction and stepped up the respiration," says DeWalle.

Though the stream chemistry data suggests increased respiration in the soil, researchers caution that the hypothesis needs to be tested with experiments that mimic reduced amounts of nitrogen in the atmosphere.

Penn State researchers are already seeing increasing amounts of silica and sodium in streams which may be from the weathering of minerals and sandstone bedrock, caused presumably by the increased carbonic acid in soil and groundwater.

"If you have higher carbon dioxide in the soil, you get more carbonic acid in the groundwater, which increases the weathering of minerals. You would not normally expect weathering rates to increase with reduced acid rain," DeWalle told attendees at the American Geophysical Union conference today (Dec. 12) in San Francisco.

Appalachian forests play a crucial role in maintaining a healthy ecosystem, and support thousands of jobs through the hardwood industry.

"This area is a region bigger than Pennsylvania, where we see declines in both sulfur and nitrogen emissions.

Although that is a positive thing, it is having an influence, it appears, on the forest ecosystem. Higher amounts of carbon dioxide in the soil means more of it ultimately may be emitted back to the atmosphere as a greenhouse gas," adds the Penn State researcher.

Amitabh Avasthi | EurekAlert!
Further information:
http://www.psu.edu

More articles from Earth Sciences:

nachricht Colorado River's connection with the ocean was a punctuated affair
16.11.2017 | University of Oregon

nachricht Researchers create largest, longest multiphysics earthquake simulation to date
14.11.2017 | Gauss Centre for Supercomputing

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

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...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

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....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>