NY lake’s freezing and thawing shows warming trend

Posted May 05, 2012, at 11:42 a.m.
Last modified May 05, 2012, at 12:09 p.m.

NEWCOMB, N.Y. — Wolf Lake in the Adirondack High Peaks region is considered a “heritage lake,” one of the most pristine freshwater bodies in the northeastern United States.

It remains as it was when European settlers arrived in North America. As part of a private preserve bordering the state-owned 300-square-mile High Peaks Wilderness Area, it has escaped pollution and the ravages of invasive plants and animals. It’s one of a dwindling number of lakes with heritage brook trout and calcium-rich soils buffering its water from fish-killing acid rain.

But there’s no shelter from climate change, and Wolf Lake’s pristine days may be numbered. A new study shows the length of time the lake is covered with ice each winter has declined by three weeks since 1975, indicating a change that may alter the lake’s ecology and harm cold-water species such as trout.

“Lake ice is a better indicator of climate than weather stations, which require instruments and people to read them and are thus prone to errors,” said ecologist Colin Beier, lead author of the study published online this week by the international journal Climatic Change. “Lake ice doesn’t lie. The process of ice formation and lake closure and opening is a straightforward physical process, and people have kept records of it for decades.”

The loss of ice cover may change a lake’s water chemistry and types of algae and plankton, which would affect the rest of the food chain. Beier said researchers have found warming to be a cause of algae blooms in several lakes in Ontario, Canada, and similar algae increases have been noted in some Adirondack lakes.

The study was conducted at the Adirondack Ecological Center in Newcomb, part of the State University of New York’s College of Environmental Science and Forestry. The center is in the 23-square-mile Huntington Wildlife Forest.

Scientists previously have documented that places like the Adirondacks that are transition zones between temperate hardwood forests and cold-loving spruce-fir forests are especially sensitive to climate change. As the climate warms, transition zones move northward or higher up mountain slopes.

In Vermont’s Green Mountains, a 2008 study found the transition zone between maple-beech forest and spruce-balsam forest moved 400 feet up the mountains over 43 years, in sync with a 2-degree rise in the area’s mean annual temperature.

Beier and his colleagues analyzed lake ice records beginning in 1975 from five lakes in the Huntington Wildlife Forest. They found all five now have a significantly shorter period of ice cover than they did in 1975, with the three largest lakes losing two to three weeks of ice.

The loss of ice time was the largest decrease seen in any published data from the Adirondacks and in the top 10 percent of any reported in the U.S. and Canada, Beier said.

“We’re finding that the lakes aren’t opening much earlier in the spring; the change is mostly in the fall, with freeze-upcoming later,” Beier said. While warmer temperatures were also noted in spring, the effect was lessened by snow cover that insulates the ice.

With very little snow and unusually mild temperatures over the past winter, lakes were iceless by late March or early April, about a week earlier than the 10-year average, Beier said.

“The vast majority of monitoring to document climate change is focused on spring,” Beier said. He said it also makes sense to study what happens in the fall, including freeze-up, when leaves drop, migration, mushrooms fruiting and insects cocooning.

Arthur Degaetano, a climate scientist and director of the Northeast Regional Climate Center at Cornell University, said Beier’s study provides independent support for the increase in winter temperature and decrease in ice cover documented by other scientists studying other lakes.

Because it includes a lake unchanged from its primeval state, the study has the added advantage of eliminating other factors that might affect the results, such as pollution, said Degaetano, who was not involved in the study.

Local studies of climate change impacts are needed to inform management, conservation and adaptation efforts as well as to foster public awareness of the nature of climate change and its consequences, Beier said.

“Climate change is a game-changer when we talk about these ecosystems,” he said.

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