“But it’s a long way from home,” she said. “It could be a sister species too, but I’ll bet you it’s from the genus Thiobacillus.”
“How can you be so sure?” Carol asked Junko.
“When I was in India, working with the United Nations, the ore samples we were assigned to inspect were loaded with this bacterium. Thiobacillus speeds up the oxidation of iron and sulfide minerals,” Junko continued. “In other words, it loves radioisotopes and helps break down sulfur, which explains why it helps to control the acidic wastewater of uranium mines. The exact effect of radiation on the bacterium’s metabolism isn’t known. But in uranium and radium mines with a low-to-marginal lode yield, Thiobacillus is being used with increasing regularity. The bacterium is fed metal sulfides and sprayed on ores with a concentration of less than 1 percent uranate, the insoluble form of natural uranium. The bacteria then convert the uranate to soluble products that are concentrated and purified.”
“Sounds like a tedious investment,” Carol said.
“The net effect on the overall yield of most mines is slight,” Junko agreed. “But in regions such as India where natural supplies are low, it can make the difference between loss and profitability. Thiobacillus was also used here in Canada to revitalize the Stanrock mine.”
“But as you said,” Garner pointed out, “it’s a long way from home.”
“Natural, abundant growths of this bacterium aren’t impossible,” Junko said. “Obviously it can survive somewhere in nature, even without mine tailings. I just wouldn’t expect it to occur anywhere radiation levels are low.”
“Then I’ll bet it’s putting on the feed bag here,” Carol said.
Junko nodded.
“The culture will grow exponentially with an appropriate food source. Like most bacteria, the other factors to consider are heat and moisture.”
“It has plenty of that too,” Garner said. “Probably why it’s made a profitable living inside the temperature anomaly.”
“But the heat source hasn’t always been here,” Carol replied. “A better question might be, where did it come from in the first place?”
“It’s hard to imagine anywhere in the Arctic that could support it for any length of time,” Junko agreed.
“Which means that the source of this contamination is either highly enriched or recently created,” Garner said.
“Most likely both,” Junko added. “Either way, it’s got to be a manmade source.”
As dusk approached, they gathered in a conference room off the main lab of the Phoenix. Zubov and Byrnes slumped in chairs, nearly catatonic with fatigue.
Conversely, Junko furiously scribbled in the spiral notebook she was using to maintain detailed medical files for everyone on board. Wearing thick cotton sweatpants, her hair pulled back in a ponytail, Carol had not been without a strong cup of coffee or a radio in her hand for the past six hours.
“How’s Medusa holding out?” Carol asked Zubov.
“The rad sensors are royally screwed,” Zubov said.
“Then God save the queen,” Carol said.
“I could use both their help,” Zubov grumbled. “It’s bad enough that we’re trying to estimate actual rad levels in solution. Add to that the magnitude of those levels and it’s pretty much a lost cause trying to get any sort of direction from the data. The water’s hot, Medusa’s hot — even the casing on the goddamn probes is hot. There’s no way we can rely on readings from any of the gear once it’s been cooked.”
“Then forget about using Medusa to track the radiation,” Garner said. “The levels will probably be off the scale anyway. We can use the dosimeters on deck every hour, or every half hour, if we need to.” They had been keeping a running log of the atmospheric radiation. While it was hardly an exact correlation with the contamination in the water, it was far less demanding on the instruments.
“What do you want to track instead?” Zubov asked.
“We’ll use the DOM channels to monitor the bacterial levels,” Garner replied.
DOM — dissolved organic matter — was a common indicator of living material too small or indistinct to be captured with nets or seen with the naked eye.
“And keep an eye on the temperature and salinity on the inorganic channels.” Garner was gambling that both the bacteria and the radionuclides coincided within a single, dilute, and clearly heated water parcel. The presence of Thiobacillus ferrooxidans and temperatures of a specific range would indirectly tell them which body of water should be followed upstream.
“What would be the ideal culture temperature of this bacterium?” Garner asked Junko. Even among arctic species, it was typically only increased temperatures that promoted such wholesale growth of microbe populations.
“I don’t know,” Junko said. “But I could make some calls if you’d like.” She thought for a moment, revisiting the extent of her experience with the organism in India. “Perhaps as little as forty-five degrees Fahrenheit.”
Forty-five degrees. Low for a lot of microbes, but still significantly warmer than the thirty-three degrees more typical of water around Baffin Island. For Thiobacillus to be this plentiful in natural samples of seawater at thirty-three degrees suggested a much warmer incubation temperature farther upstream. Despite conditions that should be significantly lethal to the organism, there were still plenty of cells left in the heated water below.
Garner ran a quick calculation through a computer model based on the volume of heated water and the activity of the Thiobacillus ferrooxidans they had recorded.
The temperatures of the hypothetical heat source predicted were improbably ― high nine hundred degrees Celsius or higher ― the kind of temperatures produced by boiling fission products. If these numbers could be believed, what they were searching for was not simply a leak of radioactive material, but an undersea nuclear fission reaction.
He nodded at the computer and its display of thermal exchange calculations.
“If this is right, there’s enough heat upstream to cause significant melting if we can’t find the source.”
“How significant?” Carol asked.
“Significant enough to make a little radioactive contamination an incidental consideration,” Garner said.
“Incidental?” Byrnes asked.
Garner adjusted the model and ran another series of speculative numbers through it. He scratched at his chin as the results were calculated.
“I wish I’d paid more attention to heat budget equations in school,” he admitted, “but these numbers look right. Left unchecked, there’s enough heat upstream to eventually dump a very large amount of warm, fresh water through the Hudson Strait and Labrador Sea into the North Atlantic.”
“So the North Atlantic gets warmer,” Byrnes said.
“Yes,” Garner said. “According to this, warm enough to hold back the normal flow of warm water flowing up from the equator.”
“So then the Arctic would get colder,” Byrnes followed.
“Right,” Garner said. “There’s enough heat being generated by the fission reactions to melt a lot of ice, to disrupt the flow of heat coming in, but not enough to replace the normal amount of incoming warm water.”
“So eventually the entire Arctic would begin to refreeze,” Carol said, “which would negate the flow of heat from the equator even further.”
“And the polar cap would continue to grow, maybe even creating a global disruption of weather patterns,” Garner said. “What we’re seeing here is a repeat of the climate conditions we think existed twelve thousand years ago.”