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fredag, april 06, 2012

Scientists identify environmental impacts of disappearing snow and ice


Author: David Santen, Office of University Communications, Portland State University
Posted: April 6, 2012 PORTLAND STATE UNIVERSITY
NEWS RELEASE

Scientists identify environmental impacts of disappearing snow and ice

PSU geologist is lead author of new study published in BioScience

(Portland, Ore.) April 6, 2012 —Portland State University (PSU) geologist Andrew Fountain is lead author in a special issue of the journal BioScience released today, focused on the long-term impacts of global environmental change and in particular, the thawing of the frozen planet.

The global cryosphere—the portion of the Earth’s surface where water is in solid form for at least one month of the year—has been shrinking in response to climate warming. This has been most obvious by the extents to which ice, snow, permafrost and glaciers have been decreasing.


“With a shrinking cryosphere, populations of microbes, plants, and animals that depend on the snow and ice will decrease if they are unable to migrate. On the other hand, life that finds the cryosphere too hostile should expand,” says Fountain (pictured, left). In shallower snow, for example, animals such as white-tailed deer, mule deer, elk, and caribou expend less energy and can more easily escape predators. “One species’ loss can be another species’ gain.”

Fountain, professor and department chair of geology at Portland State University, is lead author of the study, “The Disappearing Cryosphere: Impacts and Ecosystem Responses to Rapid Cryosphere Loss.” The journal BioScience, published by the American Institute of Biological Sciences, features results from more than 30 years of the National Science Foundation’s Long Term Ecological Research (LTER) program.

Fountain and his collaborators identified two primary outcomes for ecosystems within or that depend on the cryosphere:

•Disruptions in the food chain due to loss of habitat and the disappearance or changes of those species present;
Changes in the cycling of water, nutrients, oxygen, nitrogen and other elements that support plant and animal life.

•Whether these changes are positive or negative depends on how species—which include polar bears and penguins as well as everything from microbes to great whales—interact with and respond to their environment.
More important, Fountain notes, will be how humans respond to these changes, which could impact infrastructure, agriculture, energy production, commerce and culture.

The LTER network has amassed more than 30 years of data on environmental recovery and change. In contrast to most grant-funded research, which spans only a few years, LTER studies are often sustained over decades, documenting gradual changes and long-term variability that often cannot be revealed by short-term studies, creating a better understanding of how ecosystems respond to environmental change.

The LTER program was created in 1980 by the National Science Foundation to conduct research on ecological issues that can last decades and span huge geographical areas. The network brings together a multi-disciplinary group of more than 2000 scientists and graduate students. The 26 LTER sites encompass diverse ecosystems in the continental Unites States, Alaska, Antarctica, and islands in the Caribbean and the Pacific—including deserts, estuaries, lakes, oceans, coral reefs, prairies, forests, alpine and Arctic tundra, urban areas, and production agriculture.


The article appears in the April 2012 issue of BioScience (62: 405–415). Authors include Andrew G. Fountain (Department of Geology, Portland State University), John L. Campbell (U.S. Forest Service, Northern Research Station, Durham, N.H.), Edward A. G. Schuur (Department of Biology, University of Florida), Sharon E. Stammerjohn (Department of Ocean Sciences, University of California Santa Cruz), Mark W. Williams (Department of Geography, University of Colorado–Boulder), and Hugh W. Ducklow (Marine Biological Laboratory, Woods Hole, Mass.).



(left) Adélie penguins near the Palmer Station LTER site in Antarctica. The local population has declined by 80% since 1975 in response to climate change. Photo: Zena Cardman

Additional resources
Press release from American Institute of Biological Sciences: http://www.eurekalert.org/pub_releases/2012-04/aiob-lsd033012.php

High-resolution photographs, scientific papers and additional content: http://harvardforest.fas.harvard.edu/press-resources-release-april-6-2012-bioscience-lter

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Portland State University (PSU), a 50-acre campus located in downtown Portland, is a nationally acclaimed leader in sustainability and community-based learning. The University's position in the heart of Oregon's economic and cultural center enables PSU students and faculty to apply scholarly theory to the real-world problems of business and community organizations.
Portland State offers more than 220 undergraduate, master's, and doctoral degree options, as well as graduate certificates and continuing education programs. PSU is Oregon's largest and most diverse university, with some 30,000 students who come from all 50 states and from nearly 100 nations around the world.

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