By Joe Evancho
YELLOWSTONE NATIONAL PARK—For more than 30 years, Dr. John Varley was head scientist at Yellowstone National Park spearheading research on areas such as the controversial bison/brucellosis issue as well as studies on elk, wolves, grizzly bear and trout.
For most of that time Varley and his associates looked at Yellowstone Lake, the largest lake in North America above 7,000, as a beautiful, though rather unexciting study subject in the midst of hundreds of other more interesting and easily assessable areas of inquiry.
Varley’s reviews of the 100 years of scientific research regarding the lake found it to be ecologically plain and kind of boring. Then in 2004 everything changed.
While using a remotely operated vehicle (ROV) to explore the areas near geothermal vents on the lake bottom, a team of researchers from Montana State University and elsewhere, lead by Varley, discovered life where none was known to exist before.
“Yellowstone Lake has been studied for more than 100 years,” Varley said, “and yet nobody had done any work on the base of the food pyramid which is presumed to be what makes up the majority of the biomass in any body of water.”
As it turns out their 2004 study lead to evidence that showed that the majority of the biomass in the lake is microscopic, living in 89,000 acres of open water primarily on the bottom of the lake near geothermal vents that pour heated water and gasses into the lake in a ceaseless flow.
The majority of the life in and near the vents is microscopic, Varley said. “Everything else, the fish, crustaceans, even water plants that live throughout the lake can’t hold a candle to the volume, weight and number of bacteria and Archaea and the small eukaryotes that live in the lake,” he said.
Dr. Varley explains that there is a relatively new classification of life that is included with bacteria. Achaean (archaeans) is a group that has only been known as being separate from bacteria for about 30 years. And Eukarya (eukarayotes) includes all life that we are most familiar with.
“Trees, animals—and most embarrassingly—fungi, are eukaryotes,” he says. “In other words, what science is saying now is that humans are more closely related to fungi and trees than to Archaea and bacteria.”
Marine life in Yellowstone Lake
“One of the elements that astonished us was that many of the species in the open, cold waters at the bottom of this fresh water lake near hydrothermal vents are the same or very similar to species that are found in the oceans,” Varley said.
“Taking that ROV and getting down to the bottom of the lake near the vents just knocked our socks off because in biology, the salt barrier has always been considered to be very high.
You don’t take a fish that lives in the ocean and drop it into fresh water because it will die. And the reverse is mostly true, as well” he said. “The whole notion that salt is very exclusionary has been a mainstay of biology for many years.”
The discoveries in Yellowstone Lake involving the base of the food pyramid told the MSU researchers that it is very, very complex “and there are many, many unknown species of bacteria, Archaea and eukaryotes down there,” Varley said. “There is a whole unknown world in Yellowstone Lake that we knew nothing about. And we are still learning about it.”
Other science-shifting conclusions have been reached as a result of the MSU studies. For example, in the plumes of several of the thermal vents at the bottom of the lake there are swarms of small shrimp-like crustaceans.
“These are not microscopic as you can see them with the naked eye,” Varley said. “These warm water swarms are unusual to see anytime and the question is why and one obvious answer is that there must be a terrific food source there.”
Islands of life
Most of Yellowstone Lake is cold and dilute meaning that the water comes from snow and it is closer to distilled water than any other water type. Areas around the hydrothermal vents are geochemically rich in minerals and nutrients. These little plumes of very enriched water eventually dissipate and lose their rich nutrient signal very rapidly in the snow derived water.
The water also loses its heat and becomes more like the temperature of recently thawed snow, and the lake itself on average, is still a chemically dilute and cold water lake. These watery plumes, then, are really like islands that are warm and chemically enriched, forming unique little islands of life in a lake of a different character.
“There are algae and moss there that are only found around certain vents and apparently not found in other parts of the lake,” he said. “The moss and several algae species appear to be new species to science.”
A plume’s chemistry varies with each vent and is different than its neighbor. “Chemically, the vents are very challenging to understand. Some of these plumes have very high temperatures, above the boiling point, and the chemicals come up as gas,” Varley said.
“So between the gas, minerals and the temperatures, they are highly variable. They are much like the black smokers, those chimney-like hydrothermal structures that occur on the bottom of the ocean.”
And you may ask yourself “Well, how did they get here?”
According to Dr. Varley, that is a good question. About 16,000 years ago there was no lake where there is a lake today. Instead, there was a 2,500 ft. thick ice cap and so everything has developed in the warmer and drier period of the last 10 or 12,000 years.
“We presume that the microbes were brought in on the wind or the feathers of migratory water birds, although that has never been studied, so the biota of the lake is all of very recent origin,” Varley said.
The MSU studies have provided more questions than answers, and according to Varley, good science always does that. “I am fascinated by a number of different aspects. Just the complexity of the biodiversity has to be number one,” he said. “We are discovering species in Yellowstone Lake that no prior researchers have discovered and some are also new to science. For a biologist that’s pretty thrilling stuff.”
They are species that have not been named or even classified. When asked if he would be naming a species after himself, Varley laughed. “Naming a species after yourself is considered bad form.”
The irony of Varley’s latest scientific journey has not escaped him. “I spent most of my entire professional life with the most charismatic wildlife there is; bears, wolves, elk, and now my fascination is with the microscopic stuff and I ask myself what does that say about me, and frankly, I don’t know.”