Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Shrinking ponds signal warmer, dryer Alaska

16.10.2006
A first-of-its kind analysis of fifty years of remotely sensed imagery from the 1950s to 2002 shows a dramatic reduction in the size and number of more than 10,000 ponds in Alaska.

The analysis, by University of Alaska Fairbanks scientists and published this week in the Journal of Geophysical Research, indicates that these landscape-level changes in arctic ponds are associated with recent climate warming in Alaska and may have profound effects on climate and wildlife.

Over the past 50 years, Alaska has experienced a warming climate with longer growing seasons, increased permafrost thawing, an increase in water loss due to evaporation from open water and transpiration from vegetation, and yet no substantial change in precipitation.

The shrinking of these closed-basin ponds may be indicative of widespread lowering of the water table throughout low-lying landscapes in Interior Alaska, write the authors. A lowered water table negatively affects the ability of wetlands to regulate climate because it enhances the release of carbon dioxide by exposing soil carbon to aerobic decomposition.

“Alaska is important in terms of waterfowl production and if you have a lowering of the water table that could have a potentially huge impact on waterfowl production,” said Dave Verbyla, co-author and professor in the School of Natural Resources and Agricultural Sciences at UAF.

“This is an issue relevant to flyway management in terms of all the waterfowl that might use the Yukon Flats National Wildlife Refuge and overwinter elsewhere, and this is something that goes beyond the refuges in Alaska,” said A. David McGuire, co-author and professor of ecology at the Institute of Arctic Biology at UAF.

National Wildlife Refuges cover more than 77 million acres in Alaska and make up 81% of the national refuge system. These refuges provide breeding habitat for millions of waterfowl and shorebirds that overwinter in more southerly regions of North America.

“No one has done a state water-body inventory of this magnitude,” said Brian Riordan, lead author and data manager for the Bonanza Creek Long-Term Ecological Research program at UAF. “It will allow land managers to stop speculating about possible water body loss and begin to address the implications of this loss.”

Using black and white aerial photographs from the 1950s, color infrared aerial photographs from 1978-1982, and digital images from the Landsat satellite from 1999-2002, Riordan outlined each pond by hand. “With automated classification your accuracy goes down,” Riordan said. Cloud shadows can look like water and Alaska rarely experiences a cloudless day, said Verbyla.

The most difficult part of the four-year project, said Riordan, was “having the patience to circle 10,000 ponds for each time period.”

The main study area was the subarctic boreal region of Interior Alaska, which spans more than 5 million square kilometers bounded on the north by the Brooks Range and on the south by the Alaska Range. To contrast the semi-arid, subarctic sites of discontinuous permafrost in Interior Alaska, the authors also selected a study area in the Arctic Coastal Plain where the temperatures are much colder, the growing season much shorter, and the permafrost is continuous, and a more maritime site south of the Alaska Range.

All ponds in the study regions in subarctic Alaska showed a reduction in area of between 4 and 31 percent, with most of the change occurring since the 1970s. The ponds in the Arctic Coastal Plain showed negligible change.

Marie Gilbert | EurekAlert!
Further information:
http://www.uaf.edu

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>