facebooktwitterRSS
- Advertisement -
  • Most Commentedmost commented up
  • Most Emailedmost emailed up
  • Popularmost popular up
- Advertisement -
 

« News Home

Deep freeze has silver linings for Great Lakes, plant species



Published: Thu, January 9, 2014 @ 12:00 a.m.

Associated Press

TRAVERSE CITY, Mich.

From a field station in northern Wisconsin, where the previous night’s low was a numbing 29 degrees below zero, climate scientist John Lenters studied computer images of ice floes on Lake Superior with delight.

It may be hard to think of this week’s deep freeze as anything but miserable, but to scientists such as Lenters, there are silver linings: Heavy ice cover may help raise low water in the Great Lakes and protect shorelines and wetlands from erosion. The extreme cold also could kill some insect pests and slow the migration of invasive species.

“All around, it’s a positive thing,” said Lenters, a specialist in the climate of lakes and watersheds.

Ice cover on the Great Lakes has been shrinking for decades, but this year more than 60 percent of the surface is expected to be frozen over at some point — an occurrence that could help the lakes rebound from a prolonged slump in water levels.

Even agriculture can benefit. Although cold weather is generally no friend to crops, some of southern Florida’s citrus fruits can use a perfectly timed cool-down — which they were getting as midweek temperatures hovered around freezing.

“A good cold snap lowers the acidity in oranges and increases sugar content, sweetens the fruit,” said Frankie Hall, policy director for the Florida Farm Bureau Federation. “It’s almost been a blessing.”

Scientists noted that subzero temperatures and pounding snowfalls like those that gripped much of the nation are not unheard-of in the Midwest and Northeast and used to happen more frequently. The extremes help keep nature in balance.

“I’m just happy to see that we have a normal winter for once,” said Lenters, who works for Limnotech, an environmental consulting firm in Ann Arbor.

As the climate has warmed, the absence of bitter cold actually has been damaging.

The emerald ash borer, an insect native to Asia, arrived in the U.S. about 2002 and has killed about 50 million ash trees in the Upper Midwest. But some locales this winter may have gotten cold enough to kill at least some of their larvae, said Robert Venette, a U.S. Forest Service research biologist in St. Paul, Minn.

A reading of minus 20 usually will produce a 50 percent mortality rate, and “the numbers go up quickly as it gets colder than that,” Venette said.

Though the freeze won’t wipe out the ash borer, it will give communities a chance to develop plans for limiting the bug’s spread, he said.

Other pests that originated in warmer places could be affected as well, including the gypsy moth, the hemlock woolly adelgid and the European beetle that carries Dutch elm disease, said Lee Frelich, director of the University of Minnesota Center for Forest Ecology. Native insects have evolved to cope with deep freezes.

Extreme cold also reins in invasive nuisance plants such as kudzu, which has ravaged the Southeast but has yet to find its way north, said Luke Nave, a University of Michigan assistant research scientist.

“As long as these cold snaps continue to occur, they will help reinforce the current range limits for certain plants,” Nave said.

Water levels have been below normal in most of the Great Lakes since the late 1990s because of high evaporation and occasional lack of rain and snow. A year ago, Lakes Michigan and Huron hit their lowest points on record. Cargo ships were forced to carry lighter loads to avoid running aground in shallow channels. Marinas lost business, and wetlands dried up.

But levels rose sharply in 2013, thanks to heavy snow and rain. Extensive ice cover this winter could help the lakes continue their recovery. The National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory in Ann Arbor predicts ice will cover 57 to 62 percent of the surface waters.


Comments

Use the comment form below to begin a discussion about this content.


News
Opinion
Entertainment
Sports
Marketplace
Classifieds
Records
Discussions
Community
Help
Forms
Neighbors

HomeTerms of UsePrivacy StatementAdvertiseStaff DirectoryHelp
© 2014 Vindy.com. All rights reserved. A service of The Vindicator.
107 Vindicator Square. Youngstown, OH 44503

Phone Main: 330.747.1471 • Interactive Advertising: 330.740.2955 • Classified Advertising: 330.746.6565
Sponsored Links: Vindy Wheels | Vindy Jobs | Vindy Homes | Pittsburgh International Airport