Scientific breakthrough unveils the mystery behind Antarctica's blood falls

"As soon as I looked at the microscope images, I noticed that there were these little nanospheres and they were iron-rich, and they have lots of different elements besides iron—silicon, calcium, aluminum, sodium—and they all varied," Livi explained.

The research scientist worked in a team investigating the Taylor Glacier and Blood Falls, whose findings have been published in the peer-reviewed journal Frontiers in Astronomy and Space Sciences.

A Window to Ancient Microbial Life and Planetary Exploration

To fully comprehend the mystery of Blood Falls, understanding Antarctic microbiology is crucial. The glacier's ancient, iron- and salt-rich waters harbor microorganisms that may have existed for millions of years. 

Scientists believe that exploring this unique environment and its resilient life forms could not just enhance our understanding of Earth but also offer insights into the search for extraterrestrial life.

Livi's involvement in the project stemmed from his expertise in planetary materials and the analysis of Martian samples. He posed a fascinating question, "What would happen if a Mars Rover landed in Antarctica? Would it be able to determine what was causing the Blood Falls to be red?" This curiosity led researchers to analyze Blood Falls as if it were a landing site on Mars, employing methods akin to those used by rovers exploring the Red Planet.

The samples collected from Blood Falls during an Antarctic expedition were sent to Johns Hopkins' MCP facility. There, Livi employed transmission electron microscopy to uncover the presence of the enigmatic nanospheres. 

Although this breakthrough provides answers to the Blood Falls mystery, it also highlights a new challenge. “Our work has revealed that the analysis conducted by rover vehicles is incomplete in determining the true nature of environmental materials on planet surfaces. This is especially true for colder planets like Mars, where the materials formed may be nanosized and non-crystalline.”

“Consequently, our methods for identifying these materials are inadequate. To truly understand the nature of rocky planets’ surfaces, a transmission electron microscope would be necessary, but it is not currently feasible to place one on Mars,” he added.

In unraveling this century-old enigma, scientists have not only demystified a fascinating natural wonder but also opened doors to further exploring and understanding our planet and potentially others in the universe.

This article was written and edited by a human, with the assistance of Generative AI tools. Find out more about our policy on AI-powered writing here.

Study Abstract

Aperiodic discharge of brine at Blood Falls forms a red-tinged fan at the terminus of Taylor Glacier, Antarctica. Samples from this discharge provide an opportunity for mineralogical study at a Martian analogue study site. Environmental samples were collected in the field and analyzed in the laboratory using Fourier transform infrared, Raman, visible to near-infrared, and Mössbauer spectroscopies. Samples were further characterized using microprobe and inductively coupled plasma optical emission spectroscopy for chemistry, and x-ray diffraction, scanning electron microscopy, and transmission electron microscopy for mineralogy, crystallography, and chemistry. The mineralogy of these samples is dominated by the carbonate minerals calcite and aragonite, accompanied by quartz, feldspar, halide, and clay minerals. There is no strong evidence for crystalline iron oxide/hydroxide phases, but compositionally and morphologically diverse iron- and chlorine-rich amorphous nanospheres are found in many of the samples. These results showcase the strengths and weaknesses of different analytical methods and underscore the need for multiple complementary techniques to inform the complicated mineralogy at this locale. These analyses suggest that the red color at Blood Falls arises from oxidation of dissolved Fe2+ in the subglacial fluid that transforms upon exposure to air to form nanospheres of amorphous hydroxylated mixed-valent iron-containing material, with color also influenced by other ions in those structures. Finally, the results provide a comprehensive mineralogical analysis previously missing from the literature for an analogue site with a well-studied sub-ice microbial community. Thus, this mineral assemblage could indicate a habitable environment if found elsewhere in the Solar System.