Lisa Pratt Diary

Every scientific field trip is a fascinating mix of logistics, equipment, and intellectual curiosity. Modern field scientists are explorers following in the tradition of Darwin and Shackelton.

My name is Lisa Pratt. It's October, 2005, and I'm setting off for the far north with colleagues from Finland and Canada. We're en route to a deep gold mine where we'll sample microbial life that might provide clues to how and where life could survive on Mars. Commercial airlines don't fly where we want to go, so we're on a chartered flight, out of Yellowknife, North West Territories, Canada.

Timo Ruskeenimi from the Geological Survey of Finland and Randy Stotler from the University of Waterloo are going to help me collect water samples and install biomass filters, more than a kilometer below the surface.

Flying north towards the gold mine, we cross a hauntingly beautiful wilderness of lakes and forest. But we're not coming to look for precious metals. We seek something far more valuable: life as we don't know it, up here on the surface of the Earth.

250 miles later, we see the bright red buildings of the mine, located 66 degrees north, 111 degrees west, less than one degree from the Arctic Circle. The temperature is minus 10 degrees C. We've only got 6 days on site, so we're anxious to get going.

Underground operations at the Lupin Mine stopped 3 months ago, so we've got to carry everything down with us each day: rescue gear, batteries, gas monitors, scientific instruments, and the all-important lights, so we can see what we're doing.

Timo has visited Lupin many times and he'll lead our underground expedition. We arrange to call the safety officer every few hours to let them know where we're working.

Lupin opened in 1982, but the gold near the surface has been removed and now it's too expensive to mine rock more than a mile below the surface in such a remote location. Scientific research can't pay to tunnel deep into the Earth's crust, so getting permission to work in a commercial mine like this one is the best way to obtain samples of water and microbes from deep below the surface. Lupin is now far more valuable to scientists than to miners. But it's sad to know that this scientific treasure trove will be abandoned right after we finish our work, later this week.

In the permafrost, rock temperatures remain below freezing all year, and intricate ice crystals extend from the walls and roof. We drive as far as possible, then load our gear into back packs and coolers. We splash through the water that's rapidly flooding the mine.

Our most important study sites are drill holes located far below the permafrost where dissolved salts keep the water from freezing and we can sample for microbes. We need a fresh flow in order to collect pristine samples below the permafrost. Flowing water will flush microbes out of fractures deep in the rock walls, and will prevent contamination from microbes growing in the tunnels. Every wood and metal surface in the abandoned mine is covered in slimy mats of bacteria and fungus.

Our previous years' samples showed enough water, dissolved gases and nutrients to support life. Our task this year is to determine how many different types of organisms live below the Arctic permafrost, and to estimate how much biomass-the total weight of living organisms-exists in this deep-subsurface community. Some scientists think that the global biomass of microbes in the subsurface world may equal, or even exceed, the biomass of familiar organisms on Earth's surface.

It's hard to imagine, the total mass of trees, cows, and people weighs no more than these microscopic organisms living in cracks and pockets of water in places like this, all around our planet. Speaking of cows, gases dissolved in these subsurface waters are composed mostly of methane, the same gas that microbes make in the guts of cows and termites when they digest grass and wood. Methane can be produced by microbes, and methane can be consumed as food by other microbes. But methane alone isn't evidence of life because this gas is also produced when planets are forming.

Randy Stotler is studying the composition of gases at Lupin in order to understand how long these waters may have been cut off from the surface.

In order to analyze the chemicals dissolved in the water, we need to get rid of anything that could alter its composition before we get our samples back to the lab. So we use filters that remove any particle larger than 0.2 microns in size. These particles are so small it's hard to see them even with an electron microscope!

We sample the water and rocks to determine what's available for the microbes to eat... and to gain energy. We already know that there's a complex community of organisms down here. Some microbes in the subsurface are consumers that decompose organic matter from other organisms. But other microbes living deep down are primary producers that use simple molecules dissolved in water and extracted from rocks to make new organic matter. We call these microbes "chemo-litho-autotrophs", a fancy word that means "rock eaters."

Each day, our routine is the same: drive underground... make measurements and then return to the surface in time for dinner. Each day, we compare field notes, update our plan...

Back down...walk...sample...emerge...dry off...relax...

One evening the sky is clear and we find time for a hike to Lake Conwoyto. It's a balmy minus 8 centigrade ...

All too soon our time at Lupin is almost over. We're packing up and heading home. But leaving may be difficult and delayed. A blizzard hits. There are high winds... a foot or more of snow... and the temperature's dropping. There's no way we can avoid getting cold and wet. So this special locker room has blowers that circulate warm air.

We try to fit in as much work underground as possible before we have to go.

Since we're looking for life in the subsurface, we need to be sure we don't sample life that came down from the surface during mining activities. We wear gloves, and clean the samples sites with disinfectants... like bleach and alcohol. Some of the valves are rusted shut. And sometimes a little persuasion is required to get the water flowing...

The microbes are small and suspended in water. We use filters to concentrate the microbes. More than a thousand liters of water will flow through each filter during the six days we're at Lupin. The filter trees are attached to the end of pipes that extend back into the rock as much as 500 meters bringing us pristine sample uncontaminated by mining. Each branch on the sampling tree contains a different type of filter. If the installation goes well, we'll be able to collect 3 different samples from the exact same water flow.

Field research involves lots of time, trouble and expense getting to sample sites. Accurate interpretations by ourselves and our colleagues depend on knowing where and when and how we took each sample. Making sense of all the data means following the same procedures taught in science labs back on the surface.

Analysis of DNA from Lupin reveals dozens of different species of microbes, some requiring small amounts of oxygen, others needing no oxygen at all. We think that their ancestors may have migrated down in water perhaps 100,000 years-or maybe millions of years-ago.

Their existence, thriving deep down in the ground, under half a kilometer of permafrost, shows that life is more hardy, and more adaptable to extreme conditions, than we would ever have believed even 20 years ago.

As the last humans down here, we feel the need for something ceremonial, so all of us sign our names on the tunnel wall. We leave Lupin to the microbes, but we hope our samples will yield new organisms and a better understanding of the environmental limits for life on earth.

Back on the surface, we are packed and ready to leave. It's still gusting to 40 knots, but the charter plane makes a safe landing. All eyes are watching for a cooler. It's filled with dry ice... and that's what will keep our microscopic traveling companions cold and alive on the trip home.

Looking for life deep below the surface, and finding it in abundance, has given researchers an understanding that once you've got energy, nutrients and water, life can hold on almost anywhere. Is it the same deep below the surface of Mars? Under the ice on Europa? We could debate that question endlessly... but the only way to find out for sure is to go there... first with robots, and later, perhaps with humans.