Nature Geoscience study finds Blood Falls microbes are relics of ancient seawater
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Marine microorganisms in Antarctica’s Blood Falls confirm that the brine beneath Taylor Glacier is ancient seawater trapped when the glacier advanced, a study in Nature Geoscience shows. Analysis of 167 samples from the McMurdo Dry Valleys found that the microbial community at the glacier terminus is almost entirely marine, distinct from freshwater and terrestrial populations elsewhere in the region. The findings clarify the origin of the iron-rich crimson water that flows into proglacial Lake Bonney.
Marine Microbial Signature
The microbial community at the terminus of Taylor Glacier, where Blood Falls flows, is dominated by marine-specific taxa, according to the study led by Angela Zoumplis and colleagues. The proportion of eukaryotes shared with nearby oceanic samples was 9.34% at the glacier terminus, compared to only 1.15% at other Dry Valleys sites. The researchers applied a suite of genetic techniques to identify eukaryotic and prokaryotic taxa in 167 samples of water, sediment and air collected across the region. The results indicate that the subglacial brine feeding Blood Falls originated from seawater, not from modern wind dispersal.
Geological Isolation
Prior geochemical studies had suggested that the brine could be remnant seawater from periods when Taylor Valley was flooded. The new molecular evidence now confirms that seawater became cut off as sea levels fell and Taylor Glacier advanced. The marine microbial community likely persisted through this major environmental transition. The findings offer insights into how life can survive under extreme isolation for millions of years.
What's Next
The research team suggests that further study of these microorganisms could determine the timing of the brine’s isolation, shedding light on the evolution of the Antarctic landscape. However, the exact age of the trapped seawater and the full metabolic strategies of the microbial community remain unknown.
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Nature Geoscience study finds Blood Falls microbes are relics of ancient seawater
