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The Glacier That Bleeds

Short answer: Blood Falls is a sporadic outflow of brine at the snout of Taylor Glacier in the McMurdo Dry Valleys, where the glacier ends at ice-covered Lake Bonney. Griffith Taylor found it in 1911, and its color was first blamed on red algae.

The source is ancient seawater, concentrated by freezing and sealed beneath the glacier. Estimates range from about 1.5 million years of isolation (for the microbes living in it) to a Pliocene origin about 5 million years ago. The brine is salty, iron-rich and has no detectable oxygen. When it reaches the air, dissolved ferrous iron oxidizes into iron-rich nanospheres that stain the ice red as the brine drops 60 to 80 feet to the lake shore. A 2017 radar survey traced a brine pathway more than 300 feet long inside the glacier, making Taylor the coldest known glacier with persistently flowing water.

VideoWrite-up7 sources

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What should you know about The Glacier That Bleeds?

Quick facts. Each one stands alone and has a stable ID you can cite.

  1. Blood Falls is red because iron-rich, oxygen-free brine from beneath Taylor Glacier oxidizes the moment it meets the air.

    DD-725-F01 · Write-up · Exhibit A (Where it is)

  2. The brine stays liquid inside a glacier whose mean temperature is about -17 °C, because salt lowers its freezing point and freezing releases heat.

    DD-725-F02 · Write-up · Exhibit F (Liquid inside a cold glacier)

Video transcript: The Glacier That Bleeds: Antarctica's Glacier That Seems to Bleed

DID YOU KNOW? Blood Falls is a waterfall at the front of Taylor Glacier in Antarctica, where deep red water flows from beneath the ice, creating the appearance of blood spilling onto the frozen landscape. The unusual color comes from iron-rich, hypersaline water that has been trapped beneath the glacier for millions of years. When this oxygen-poor brine reaches the surface, the dissolved iron reacts with oxygen in the air and rapidly oxidizes. NOW YOU KNOW!

Burned-in captions, read frame by frame (see transcript.md) · 22.8s Reel ·

Video coming soonThe Glacier That Bleeds · Instagram Reel
The Glacier That Bleeds: Antarctica's Glacier That Seems to Bleed Instagram Reel · · 22.8s

The write-up

Antarctica's glacier that seems to bleed. Iron-rich brine from beneath Taylor Glacier rusts red the moment it meets the air.

  1. Exhibit A

    Where it is

    Blood Falls is at the snout of Taylor Glacier, an outlet of the East Antarctic Ice Sheet that ends in Lake Bonney in the McMurdo Dry Valleys. The red brine drops 60 to 80 feet to the shore of the frozen lake.

  2. Exhibit B

    Not algae

    Griffith Taylor discovered it in 1911, and the color was first attributed to red algae. It actually comes from iron in brine that reacts on contact with air.

  3. Exhibit C

    Ancient seawater

    The brine's chemistry matches seawater concentrated by freezing. It's thought to be a remnant of a Pliocene marine incursion about 5 million years ago, and its microbes have been isolated for an estimated 1.5 million years.

  4. Exhibit D

    No oxygen

    At its source the outflow is iron-rich (3.8 mM total iron) and has no detectable oxygen. Microbes inside it survive by cycling iron and sulfur compounds.

  5. Exhibit E

    Why red

    A 2023 analysis found no strong evidence of crystalline rust minerals. Instead, the color comes from amorphous, iron-rich nanospheres that form as dissolved iron oxidizes in air.

  6. Exhibit F

    Liquid inside a cold glacier

    Radar traced a brine pathway more than 300 feet long inside the glacier. The brine stays liquid because salt lowers its freezing point and freezing releases latent heat, making Taylor the coldest known glacier with persistently flowing water.

Questions people ask about The Glacier That Bleeds

Which glacier is Blood Falls on?

It's in the McMurdo Dry Valleys, ending at Lake Bonney.

Source: Write-up · Exhibit A (Where it is) · Badgeley et al., An englacial hydrologic system of brine within a cold glacier: Blood Falls (Journal of Glaciology, 2017); Solving the mystery of Antarctica's 'Blood Falls' (Cambridge Core Blog, 2017)

What was the red color first blamed on?

Griffith Taylor found the falls in 1911.

Source: Write-up · Exhibit B (Not algae) · Researchers solve the century-old mystery of Blood Falls (University of Alaska Fairbanks); Solving the mystery of Antarctica's 'Blood Falls' (Cambridge Core Blog, 2017)

What makes the brine turn red?

It forms iron-rich nanospheres.

Source: Write-up · Exhibit E (Why red) · Sheffer et al., A Multi-Technique Analysis of Surface Materials From Blood Falls (Frontiers in Astronomy and Space Sciences, 2023); Seeing red: Researchers uncover the century-old mystery of Blood Falls (Johns Hopkins Hub, 2023)

How much oxygen is in the brine at its source?

Microbes survive by cycling iron and sulfur instead.

Source: Write-up · Exhibit D (No oxygen) · Mikucki & Priscu, Bacterial Diversity Associated with Blood Falls (Applied and Environmental Microbiology, 2007); Life at Blood Falls (NASA Astrobiology, 2009)

Why doesn't the brine freeze inside the glacier?

Taylor is the coldest known glacier with persistently flowing water.

Source: Write-up · Exhibit F (Liquid inside a cold glacier) · Badgeley et al., An englacial hydrologic system of brine within a cold glacier: Blood Falls (Journal of Glaciology, 2017); Researchers solve the century-old mystery of Blood Falls (University of Alaska Fairbanks)

Test Your Knowledge

All quizzes →

5 questions, all from this case file. Answers are revealed instantly.

  1. Which glacier is Blood Falls on?

    1. Thwaites
    2. Taylor
    3. Beardmore
    4. Lambert
    Show the answer

    Answer: B. Taylor It's in the McMurdo Dry Valleys, ending at Lake Bonney. Source: Write-up · Exhibit A (Where it is) · Badgeley et al., An englacial hydrologic system of brine within a cold glacier: Blood Falls (Journal of Glaciology, 2017); Solving the mystery of Antarctica's 'Blood Falls' (Cambridge Core Blog, 2017)

  2. What was the red color first blamed on?

    1. Volcanic ash
    2. Red algae
    3. Blood from seals
    4. Paint
    Show the answer

    Answer: B. Red algae Griffith Taylor found the falls in 1911. Source: Write-up · Exhibit B (Not algae) · Researchers solve the century-old mystery of Blood Falls (University of Alaska Fairbanks); Solving the mystery of Antarctica's 'Blood Falls' (Cambridge Core Blog, 2017)

  3. What makes the brine turn red?

    1. Algae
    2. Dissolved iron oxidizing in air
    3. Copper
    4. Sunlight
    Show the answer

    Answer: B. Dissolved iron oxidizing in air It forms iron-rich nanospheres. Source: Write-up · Exhibit E (Why red) · Sheffer et al., A Multi-Technique Analysis of Surface Materials From Blood Falls (Frontiers in Astronomy and Space Sciences, 2023); Seeing red: Researchers uncover the century-old mystery of Blood Falls (Johns Hopkins Hub, 2023)

  4. How much oxygen is in the brine at its source?

    1. More than seawater
    2. None detectable
    3. The same as air
    4. Pure oxygen
    Show the answer

    Answer: B. None detectable Microbes survive by cycling iron and sulfur instead. Source: Write-up · Exhibit D (No oxygen) · Mikucki & Priscu, Bacterial Diversity Associated with Blood Falls (Applied and Environmental Microbiology, 2007); Life at Blood Falls (NASA Astrobiology, 2009)

  5. Why doesn't the brine freeze inside the glacier?

    1. Geothermal vents
    2. Salt plus the heat released by freezing
    3. It's moving too fast
    4. Sunlight
    Show the answer

    Answer: B. Salt plus the heat released by freezing Taylor is the coldest known glacier with persistently flowing water. Source: Write-up · Exhibit F (Liquid inside a cold glacier) · Badgeley et al., An englacial hydrologic system of brine within a cold glacier: Blood Falls (Journal of Glaciology, 2017); Researchers solve the century-old mystery of Blood Falls (University of Alaska Fairbanks)

Cite this case file

Easterling, Marcus. "The Glacier That Bleeds." The Detail Department (DetailEnjoyer), case file DD-725, last updated Jul 1, 2026. https://detailenjoyer.com/case/the-glacier-that-bleeds/

Permalink: https://detailenjoyer.com/case/the-glacier-that-bleeds/ · Last updated

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