Wednesday, May 10, 2000

By TOM PAULSON
SEATTLE POST-INTELLIGENCER REPORTER

It was the largest landslide in recorded history and it hit Spirit Lake at some 150 mph with a tree-clogged, toxic mudflow that sent the lake sloshing more than 800 feet up the opposing bank.

A view of Sprit Lake from Harry's Ridge. The lake is well on its way to full rehabilitation -- even if it is now 10 percent smaller and much shallower. U.S. Geological Survey

The eruption of Mount St. Helens temporarily killed Spirit Lake, but the volcano gave back what it took at a 5-for-1 exchange rate.

The massive avalanche and mudflow created two new major bodies of water, Coldwater and Castle lakes, and increased the number of high-elevation lakes and ponds around the mountain from 30 to more than 150. It even gave Spirit Lake a more elevated stature in the world, filling in the lake bed and raising the surface of the water several hundred feet.

Still, you never get something for nothing.

"Spirit Lake will never be the same," said Douglas Larson, a limnologist (lake scientist) and adjunct professor of biology at Portland State University who has spent years studying the lakes around St. Helens.

The dramatic change to Spirit Lake and to other aquatic systems around the volcano was exciting for scientists.

"The biology was altered in a matter of minutes," Larson said.

What had been a pristine, alpine lake ringed by old-growth conifer forests suddenly became a hot, toxic sludge hole for volcano effluent.

Larson, at the time a U.S. Army Corps of Engineers researcher, was one of the first scientists who rushed to the mountain to establish a baseline for studying how a lake recovers from such an onslaught.

He and others entered the blast zone early, making a number of interesting discoveries, including that of two new species of Legionella bacteria that made many of them ill.

"It was like one of the worst cases of flu I ever had," Larson recalled.

The illnesses were kept quiet at the time, he added, because officials didn't want to raise a panic. Some even disputed the validity of the diagnosis of a new form of Legionnaire's disease on St. Helens, Larson said, but subsequent studies confirmed it.

One Oregon State University researcher, Jim Sedell, within two days got "sick as a dog" after jumping into the warm, brown lake to collect water samples. Sedell later became a sample himself, of interest to epidemiologists.

"It was just one of the many obstacles we encountered trying to do research up there," Larson said. "In a way, it was an example of what we learned up there . . . that all the air-breathing creatures were gone and the bacteria had taken over."

The day after the eruption, Spirit Lake was the temperature of a hot bath. It bubbled like a witch's cauldron from the volcanic gases seeping up from the lake bed.

But even before the eruption, the lake wasn't so great for living creatures. In fact, the clear, pristine waters treasured by tourists signified a lack of living creatures.

"Spirit Lake, like most Cascade lakes, was originally fishless," said Charlie Crisafulli, a U.S. Forest Service ecologist at the Pacific Northwest Research Station in Olympia who has studied St. Helens since 1981. The lake, Crisafulli said, had fish only because it had been stocked repeatedly since 1913.

Some of the fish in the other ice-covered lakes around St. Helens survived the eruption, he said.

Nothing was left alive in Spirit Lake.

John Baross, a University of Washington professor of oceanography and an expert on aquatic microorganisms, documented the first post-eruption signs of life -- a rapid increase in the kind of bacteria that thrive in toxic environments without oxygen.

Baross also encountered Legionella. Despite official denials of what was initially called "red zone illness," he was among those who alerted other researchers to the potential hazard of doing science on the volcano.

No known cases have been identified since those initial outbreaks, but given the bacterial conquest of Spirit Lake, many scientists at first thought Spirit Lake was headed for a long toxic stagnation. Hazardous gases such as hydrogen sulfide, combined with high concentrations of metals such as mercury, lead and cadmium, appeared to be driving Spirit Lake toward an ugly future.

"A month after the eruption, the lake was completely devoid of oxygen," Larson said.

But this didn't last. It turns out all those dead trees swept by the landslide off the hills and into the lake served a purpose -- fertilizer. In 1982, scientists noticed key chemical and biological changes.

The heavy Northwest precipitation that constantly fed the watershed and flushed Spirit Lake also helped tip the balance against the toxin-loving bacteria. The lake began to favor oxygen-loving bugs that photosynthesize.

Complex life forms -- fish and humans -- depend on a chain of events that starts with creatures that take in the sun's energy and turn it into food. In Spirit Lake, it was phytoplankton.

More phytoplankton meant more oxygen. Next came other microorganisms, algae and aquatic insects -- to the point where Spirit Lake had more biological activity than ever before.

"It went from a relative unproductive lake prior to the eruption to a highly productive lake by 1982 and 1983," Larson said.

Fish were discovered in the lake in 1993, though it's still not known if they were survivors from ice-covered lakes that swam into Spirit Lake through streams or if hatchery fingerlings were secretly planted by an impatient fisherman.

In any case, Spirit Lake is well on its way to full rehabilitation -- even if it's now 10 percent smaller and much shallower.

"There was a remarkable recovery," Crisafulli said. The rapid turnover from a toxic sludge hole to a cornucopia of life surprised scientists, he said, and demonstrated how little we know about the complex biology of recovery.

And we still know even less than we could have learned from St. Helens, Larson contends.

"There's been very little research done up there since 1986," he said.

The U.S. Forest Service, which has jurisdiction, did little to support research at St. Helens immediately after the eruption, he said, and has done little since.

"They haven't had much interest in the science," Larson said. "What we have up there now is not so much an area for scientific study as a tourist theme park."

Crisafulli agreed that science has not always taken the top priority at St. Helens. But he bristles at Larson's criticism.

"We could use more support for research," he said. But research continues and it's not necessarily the Forest Service's job to sponsor all the studies everyone wants to do up on the mountain, Crisafulli said.

"We're still at the beginning of a recovery process that will take hundreds of years to complete," he said. "We now have new tools, such as remote satellite analyses of biological change, that can help us answer questions in new ways."