Seeing red: Researchers uncover the century-old mystery of Blood Falls

During the infamous Terra Nova Expedition to Antarctica in 1911, British geologist Thomas Griffith Taylor made a mysterious discovery at the rocky base of the glacier that now bears his name: a waterfall of what appeared to be blood.

Discharged from beneath the ice at the glacier's tongue, the water emerges clear but then quickly turns crimson. For more than a century, this phenomenon that Taylor dubbed "Blood Falls" has captured people's imaginations and remained a scientific mystery—until now.

Using powerful transmission electron microscopes at Johns Hopkins' Materials Characterization and Processing facility, Ken Livi, a research scientist in the Whiting School's Department of Materials Science and Engineering, examined solids in samples of Blood Falls' water and found an abundance of tiny, iron-rich nanospheres that oxidize, turning the water seemingly gory. (Nanospheres are tiny round objects—100th the size of the average human red blood cell—with unique physical and chemical characteristics.)

"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 in them besides iron—silicon, calcium, aluminum, sodium—and they all varied," Livi said.

Livi worked on the project as part of a team that included experts at other institutions, including Jill A. Mikucki, a University of Tennessee microbiologist who has been investigating the Taylor Glacier and Blood Falls for years. Their results appeared in Frontiers in Astronomy and Space Sciences.

Livi says that the nature of the nanospheres he identified went undetected not only because they are minuscule, but also because previous research teams believed that some sort of mineral was causing the "bloody" water, and the real culprit—nanospheres—aren't minerals.

"In order to be a mineral, atoms must be arranged in a very specific, crystalline, structure. These nanospheres aren't crystalline, so the methods previously used to examine the solids did not detect them," said Livi.

To understand the longstanding Blood Falls mystery, you must first understand Antarctic microbiology, according to Livi.

"There are microorganisms that have been existing for potentially millions of years underneath the saline waters of the Antarctic glacier. These are ancient waters," he said.

The ancient iron- and salt-rich waters under the glacier are host to strains of bacteria that may not have changed for millennia. Scientists believe that understanding this highly unusual environment and its lifeforms could also inform the search for—and understanding of—life on other planets with similarly inhospitable environments. In fact, that is how Livi, an expert in planetary materials, came to tackle the mystery of Blood Falls.

"With the advent of the Mars Rover missions, there was an interest in trying to analyze the solids that came out of the waters of Blood Falls as if it was a Martian landing site," he said. "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? It's a fascinating question and one that several researchers were considering."

One of those was Mikucki, whose team had previously conducted an analysis of Blood Falls samples using devices and methods identical to those employed by rovers traversing the surface of the Red Planet. A prolific Antarctic researcher, Mikucki was part of the team that first identified the presence of living organisms in the lake beneath the Taylor Glacier. That team mapped the caves and rivers of the glacier to the water's source: an ancient, briny subglacial reservoir containing myriad minerals gathered by the ice in its crawl across the rocks below. The reason for the water's startling gory appearance, though, remained unclear.

So Mikucki and astronomer Darby Dyar from Mount Holyoke College sent the samples from Mikucki's most recent Antarctic expedition to Hopkins' state-of-the-art MCP facility to be tested by Livi, a specialist in transmission electron microscopy, and he uncovered the nanospheres.

Livi is confident that the team has solved the Blood Falls mystery but says its research has uncovered another issue that now needs to be addressed.

"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 currently not feasible to place one on Mars," he said.