Polar bears: How far can they swim?

Posted on May 24, 2012 by Bob Berwyn

Scientists try to assess potential impact of shrinking sea ice

Some Polar bears in the Arctic can swim in excess of 200 miles, according to USGS research.

Scientists track Polar bears with by attaching GPS equipped collars to a sample population. These collars transmit data that help develop maps like this one that shows a swim of nearly 220 miles long. MAP COURTESY USGS.

By Bob Berwyn

SUMMIT COUNTY — Given the steady decline of sea ice in the Arctic and the status of polar bears as threatened under the Endangered Species Act, biologists are trying to understand how the top-level predators might respond to those changing conditions.

It’s important because some of the most recent studies link declining sea ice with dropping polar bear survival and reproduction rates in the Southern Beaufort Sea and around Hudson Bay.

“With the sea ice retreating earlier and coming back later, there’s less time for them to hunt in the spring, when put on their fat,” said Alaska-based U.S. Geological Survey researcher Anthony Pagano. “They end up in poor body condition,” Pagano said, adding that some of the studies suggest a downward trend in average body weight. (more…)

Filed under: biodiversity, climate and weather, endangered species, Environment, global warming | Tagged: , , , , , , | Leave a Comment »

Coastal wetlands at risk from global warming

Posted on December 6, 2010 by Bob Berwyn

Sediment availability the key for long-term survival

Many coastal wetlands, which provide crucial habitat for many species, could quickly disappear in some global warming scenarios.

By Summit Voice

Many coastal wetlands worldwide — including several on the U.S. Atlantic coast — may be more sensitive than previously thought to climate change and sea-level rise projections for the 21st century.

U.S. Geological Survey scientists reached this conclusion from an international research modeling effort published today in the journal Geophysical Research Letters, a publication of the American Geophysical Union. Scientists identified conditions under which coastal wetlands could survive rising sea level.

Using a rapid sea-level rise scenario, most coastal wetlands worldwide will disappear near the end of the 21st century. In contrast, under the slow sea-level rise projection, wetlands with low sediment availability and low tidal ranges are vulnerable and may drown. However, in the slow sea-level rise projection, wetlands with higher sediment availability would be more likely to survive. (more…)

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USGS study documents widespread river damage

Posted on November 4, 2010 by Bob Berwyn

A new USGS study documents widespread impacts to streams and rivers.

New study shows how many streams have been degraded by flow alterations and establishes a network of  high quality ‘reference streams’

By Summit Voice

SUMMIT COUNTY — A nationwide study by the U.S. Geological Survey shows that flow regimes have been “pervasively altered” to the detriment of aquatic ecoystems in about 90 percent of the waters that were surveyed by the federal agency. Flow alterations are a primary contributor to degraded river ecosystems and loss of native species, according to the USGS.

“This … assessment provides the most geographically extensive analysis to date of stream flow alteration,” said Bill Werkheiser, USGS associate director for water. “Findings show the pervasiveness of stream flow alteration resulting from land and water management, the significant impact of altered stream flow on aquatic organisms, and the importance of considering this factor for sustaining and restoring  the health of the nation’s streams and ecosystems.” (more…)

Filed under: rivers, Summit County Colorado | Tagged: , , , , , , , , , , | 1 Comment »

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