"For us, this is an extreme environment. But for the microbes, this is home.” – Manfredo Seufferheld
MENDOZA, ARGENTINA – We head out to Fiambala tomorrow, near the base of Ojos del Salado, the tallest active volcano in the world. We will continue our acclimatization hikes at higher and higher altitudes before beginning our approach on the lake, where we hope to collect microbial samples without contaminating the lake with our own.
We have a sense of urgency about this trip, as Francisco discovered that a team of high-altitude swimmers had tried to reach the highest lake in the world for a swim just this October! They didn't make it, but had planned to break through the ice with chainsaws and jump in. Had they succeeded they would have ruined much of the scientific potential of the lake.
So why would anyone want to climb a volcano to look for microbes in a lake?
The answer is complicated, and begins with Manfredo Seufferheld, a visiting scientist at the University of Illinois (and Francisco’s brother), who studies insect-microbe interactions and the evolution of cellular structures called organelles – the "little organs" within cells that perform the basic functions of life.
Just as paleontologists study human bones to understand human evolution, researchers like Manfredo Seufferheld can look at the cellular and molecular structures within organisms to discover how the organisms are related to one another and which structures came first in life and which evolved more recently.
If this expedition is successful and actually gets the samples, Manfredo will study them with U. of I. bioinformatics professor Gustavo Caetano-Anollés, who reconstructs ancient evolutionary events by analyzing protein structures, called folds, which are found in all organisms.
Many other researchers – in the U.S. and Argentina – also will receive samples from the highest lake in the world.
The expedition will not be able to collect and preserve living microbes. Instead, the team hopes to collect microbial DNA and RNA. Gene sequences can help identify the critters that live in this lake and how the microbial community is structured. This could help determine who is closely related to whom, and help identify more branches (or twigs) on the universal Tree of Life.
Other scientists who may join the research effort include U. of I. microbiology professor Rachel Whitaker, who studies extremophile microbes found in isolated environments such as hot springs; and Maria E. Farias, a microbiologist at the National Scientific and Technical Research Council in Tucuman, Argentina, who studies microbes found in other high Andean lakes of Argentina.
Microbiologists are always sampling new environments because they're always looking for new domains of life, Gustavo Caetano-Anollés told me in an interview before the expedition began. They also are developing new ways of looking at the molecular data. Just as U of I microbiologist Carl Woese discovered the archaea – a superkingdom of life previously unknown to science – by studying the molecular characteristics of a subunit of the ribosome, scientists are piecing together the molecular clues that they hope will help fill in the gaps in our understanding of the origins of life. Microbes are like vast libraries of evolutionary data that scientists are only beginning to learn to read. And microbes living in extreme environments may offer the best clues to how life got started on early Earth – which was quite extreme.
Although it is unlikely that the Inca and their predecessors failed to notice – and visit – the highest lake in the world, it is good that this lake near the summit of Ojos del Salado is more isolated than other lakes that have been sampled at lower elevations, Caetano-Anollés said. "Because you would want to get a sample in an environment that is pristine enough that perhaps you'll find something new – some dark matter that jumps out at you. You never know."
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