The search for life on Mars begins in Siberia
NASA and Russian scientists have been selected to take the search for life in the solar system to the frozen reaches of Earth. Richard Hoover of NASA's Marshall Space Flight Center and Prof. Elena A. Vorobyova of Moscow State University will investigate the microbiota found in the permafrost and ice of Siberia, Alaska, and Antarctica.
NASA's Office of Space Science has announced that their proposal, Permafrost as Microbial Habitat - in-situ Investigation, was one of 18 chosen from 123 proposals submitted for funding under the Joint U.S./Russian Research in Space Science (JURRISS) Program.
"The microorganisms found in the permafrost, glaciers, and polar ice caps of Earth are of profound significance to astrobiology," Hoover said . "Dormant ancient microbes, and even higher plants such as moss, can remain viable by cryopreservation, resuming metabolic activity upon thawing after being frozen in glacial ice or permafrost for thousands to millions of years.
"The microbial extremophiles in the Arctic and Antarctic glaciers and permafrost represent analogues for cells that might be encountered in the permafrost or ice caps of Mars or other icy bodies of the solar system."
Hoover is a solar scientist by training who is applying his passion for diatoms - "nature's living jewels" - to NASA's astrobiology research. He is a co-investigator on two of the major research initiatives that NASA selected last year for its new Astrobiology Institute. Hoover's research on astromaterials is concerned with the microstructure and chemical composition of microfossils in ancient rocks and meteorites. He is collaborating on these projects with Alexei Rozanov, director of the Institute of Paleontology of the Russian Academy of Sciences. He also is examining microorganisms from 3.6 km (2.3 mi) beneath the ice sheet above Lake Vostok, Antarctica.
Their object is to investigate the microorganisms in the permafrost - permanently frozen soil - and to establish morphological characteristics and chemical biomarkers by which these microbes can be recognized. For more than a century scientists have studied the the frozen remains of mammoths and other creatures that died and were preserved during the last ice age.
Hoover and Vorobyova find greater import in far smaller organisms. Diatoms, bacteria, yeasts, cyanobacteria and other microorganisms may thrive in the ice and permafrost. Other microbes can be revived after being frozen for long periods. While some microbes, plants and even large mammals such as mammoth and bison are dead, they may contain magnificently preserved cellular components, DNA, RNA, proteins and enzymes.
"Icy bodies are by far the most numerous of the solar system," Hoover pointed out. "The dirty snowballs we call comets, the ice-encrusted oceans of the Jovian moons of Europa and Callisto, the icy moons of Saturn, and the polar ice caps and permafrost of Mars are of paramount importance to astrobiology. They may harbor active microorganisms; ancient microbes that remain viable in a deep anabiosis (i.e., suspended animation) or even long-dead microbes with their microstructure, biochemistry, and perhaps even genetic material preserved."
"We are studying the microorganisms found in the Arctic and Antarctic permafrost, glaciers and ice sheets," Hoover said. "This is a very stable ecosystem because the temperature remains the same for long periods of time. The paleolife of the permafrost may hold keys to the evolution of life on Earth and the distribution of life in the cosmos."
Hoover said three types of life forms are found in permafrost: active ones that eke out a living, forms in suspended anabiosis until things get better, and the ones that simply gave up and died.
"We're very excited about the living microbes and plants that we have found in permafrost and on ice wedges and glaciers and the viable but long dormant, ancient microorganisms that can be cultured from the deep ice cores," Hoover said. "Even dead microbes from ancient permafrost and deep ice are tremendously interesting due to their state of preservation."
These preserved life forms (from diatoms and bacteria to mammoths) can yield genetic material for clues about how life has changed on the molecular level and provide a treasure trove of ancient enzymes, proteins, and biochemicals. The ecosystems of the ice and permafrost should provide clues to the potential for life in the permafrost or ice caps of Mars, comets, and on the ice-covered moons of Jupiter (Europa, Ganymede, Callisto) and Saturn (Miranda, Titan), among others.
"We also need to understand glaciers to know what to look for and how to seek life on the ice caps of Mars," Hoover explained. For example, cryoconite holes can be temporary glacial micro-Edens. Cryoconite is rock debris broken from mountains and rock surfaces by the moving ice and captured in the ice.
When dark cryoconite is transported near the surface of the ice, it absorbs sunlight and becomes warm enough to melt the ice to produce a hole with liquid water, rich in minerals and nutrients from the rock dust, below the rock. For a few hours or weeks, it's springtime on the glacial ice for a world of minute diatoms, cyanobacteria, green algae, protozoa, rotifers, and even animals like tardigrades and nematodes.
To understand where to look, Hoover and Vorobyova will study the microbial content of permafrost and the structure of the interface between the soil and ice, and develop techniques that could be used in exploring Mars, Europa, comets, and other icy worlds of our Solar System.
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