A study published in the journal Nature Geoscience has revealed that the crimson water of Gizmodo in Antarctica is of ancient marine origin. The waterfall, which pours from the Taylor Glacier into Lake Bonney in the McMurdo Dry Valleys, gets its blood-red color from iron-rich brine that rusts upon contact with the air.
Marine Microbes in a Polar Desert
Researchers analyzed 167 samples of air, sediment, ice, and water from the region to determine the source of the outflow. Using genetic techniques and DNA sequencing, the team identified a community of microorganisms in the red ice, mud, and sediment at the glacier’s terminus that are typically associated with marine environments. In contrast, surrounding sites were dominated by terrestrial and freshwater populations.
The study found that 9.34 percent of the microorganisms at Blood Falls were shared with nearby ocean samples, while only 1.15 percent were shared at other Dry Valley sites. The identified marine microorganisms include ciliates, dinoflagellates, haptophytes, and diatoms. Andrew Allen, a marine biology professor at the Scripps Institution of Oceanography and co-author of the study, described the site as effectively a marine oasis in a polar desert located more than 20 miles from the ocean.
Ancient Origins and Isolation
The findings support a hypothesis that the brine was once seawater that flooded Taylor Valley during a past warm period. This water likely became trapped beneath the advancing glacier after sea levels fell. Researchers suggest these marine communities have remained isolated beneath the ice for hundreds of thousands of years.
According to Allen, the inclusion of eukaryotes—organisms with a nucleus—provides an independent line of evidence for this relic marine system. He noted that the diverse microbial community demonstrates the adaptability and resilience of life in harsh environments. Allen stated that the information within these eukaryotes may eventually help researchers constrain the timing of the flooding and isolation event to better understand how the polar landscape evolved.
Keep reading
