Mysteries at bottom of Lake Minnewaska - 21 August, 2006

By Deborah Medenbach
dmedenbach@th-record.com
Times Herald-Record
August 21, 2006

Divers, Scientists Drawn to Lake
Gardiner â€” "Dead" is subjective.

Don't call Lake Minnewaska a "dead lake" within earshot of scuba divers. It may not have fish, but it does have a unique underwater ecosystem that divers and biologists marvel at.

Park visitors encounter all manner of animals and plants on the land, but another vibrant world lies just below the water's surface.

Biology teacher Roland Bahret of New Paltz remembers the sensation of swimming through molten glass. The lake was so clear in the early 1990s that he could see 72 feet down to the lake bottom. That clarity may explain why a mat of rare "sphagnum trinitense" moss could adapt and grow 36 feet beneath the surface.

"It's really an underwater peat bog," said Norton Miller of the State Museum in Albany. "There's no other place in New York state where this occurs."

Miller said some colonies like this at even greater depths are known in Europe, but scientists don't know why the moss, which normally floats on or close to the surface, adapts so well to its environment. "We've never seen it this abundant," said Miller, who published the first scientific papers about the lake's moss in 1994.

"If they're not already doing it, I hope the state will monitor the life at the bottom of the lake as carefully as they monitor other parts of the landscape," Bahret said.

Bahret helped document both the globally-protected moss and the deep-water habits of salamanders never known to live more than a few feet from the surface.

"The two-line salamander doesn't even bother to protect its eggs in the lake because there are no predators," said Bob O'Brien, of the Minnewaska State Park Preserve. "It's a behavior that is found nowhere else in these creatures."

Northern red salamanders are abundant, appearing ghostly white against the rocks at depths greater than 20 feet. It's not that the salamander's spotted skin has lost its color. It's that red light doesn't penetrate water very well.

Divers glide past smooth stone cliffs laced with white biomass tendrils that ripple like a gentle waterfall more than 30 feet below the surface. The silence is broken only by bubbles rising from the regulator.

An unoccupied beaver dam 20 feet under water is now a haven for smaller creatures that scuttle around its basket weave of pointed saplings.

Damselflies and hellgrammites dash along the lake's bottom in shallower waters near feathery stands of bladderwort. The carnivorous plant feeds on insects when it can't get enough sustenance from the water itself. Quillwort spikes through the sediment-laden lake floor and provides a nursery for infant amphibians.

The most unexpected surprises come from the abundance of water snakes in the lake that bolt across the surface or lie in sleeping coils on submerged rocks.

"Water snakes are curious and will seek you out if you're the only interesting thing in the water. They're non-poisonous, but freak people out," said researcher Paul Huth of the Smiley Research Center at Mohonk.

Divers complain that the water's clarity has decreased over the last 10 years. Huth said clarity is a seasonal thing.

"The worst is typically in August, when there are phytoplankton blooms," he said. The lake is clearest in the spring and early summer.

Want to go below?

Exploring the underwater world of Lake Minnewaska requires diving certification and $20 annual diving fee. Dive teams from Dutchess Diving Center in Poughkeepsie and Deep Six Divers in New Paltz occasionally offer group explorations of the deepest part of the lake. Divers enter at Diver's Cove. All divers must sign in and out at the main office at Peterskill.

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