Water And Oceanography

What causes a Lake to Turn Red

Brenda Speegle's image for:
"What causes a Lake to Turn Red"
Image by: 

Tales abound about lake water turning blood red and rivers flowing with blood instead of water. Reports of blood red lakes were children's Bible stories until people of modern times began witnessing the phenomenon around the world. Are blood red waters a sign the end is near?

When Lake Camargue in Southern France turned strawberry red, residents began preparing for the apocalypse. A lake in Texas turned blood red during a severe drought in 2011, causing doomsday predictions throughout the nation. Scientists, however, have found a much less nihilistic reason for the red lake water.

The feast of billions

Lakes containing high levels of salt are home to a micro-algae called Dunaliella salina. During drought years, the water evaporates, leaving dense salt deposits that are home to billions of these hungry microscopic feeders. As they feed on salt deposits, they glow pink with energy, then get red as protective carotenoid fills the cell. These micro-algae multiply as the feast continues, and they cover the surface of salt lakes around the world.

The Great Salt Lake in Utah flourishes with these microbes and during hot summer months, parts of the massive lake glow red. In California's eastern deserts, salt deposits lie in valleys near the Sierra Nevada foothills. Boron mines used salt and mineral deposits in the area for the manufacturing of cleaning products. After heavy rain or flash floods, creeks that usually sit dry run with red water until it all evaporates.

Red tides around Sydney

Red waves rolled onto beaches around Sydney Australia in late 2012 and swimmers had to get out of the water. An overgrowth of algae called Scintillans caused the red tide. The overgrowth happens often and the algae grow in many different colors.  A long period of cold weather and the upwelling of cold water filled with nutrients cause the phenomenon. The water tests safe for humans but the algae release ammonia into the water, which irritates skin and eyes.

China Golden River runs red

The River in China turned red in September 2012 and baffled residents as well as scientists. China experienced torrential rains in the mountainous regions near the river throughout the winter and fall. Scientists suggested an overgrowth of Nocturnal Scintillans as a culprit, but the phenomenon normally occurs in salt water.

The most likely reason for the red Yangtze River is high concentrates of industrial pollutants settled into the silt on the river's bed that washed into the running water after the mudslides. A similar incident in the past had turned parts of the river red. After investigating, authorities discovered industrial dyes illegally dumped in the river caused the discoloration.

Life comes out of ice

The five-story-tall Blood Falls in Antarctica is a massive example of non-apocalyptic red water. An ancient lake lies under the massive glacier, and a unique ecosystem of microbes lives inside. The microbes thrive in an environment with little oxygen or heat. A rift in the glacier allows the microbe-rich water from the ancient lake to flow out as a slow-moving waterfall that drops five stories into McMurdo's Dry Valley. The rift lets the bright red water out, but does not allow any harmful environmental factors access to destroy the delicate life that thrives inside.

Lake water's turning red happens because of natural organisms living underneath. Algae beds and microbes going about their daily habits turn human heads and spark doomsday rumors. Pollutants from industrialized nations are much more frightening and harder to manage than naturally occurring reactions that tint the water red.

More about this author: Brenda Speegle

From Around the Web

  • InfoBoxCallToAction ActionArrowhttp://www.huffingtonpost.co.uk/2012/08/14/blood-red-lake-south-france-camargue_n_1775048.html
  • InfoBoxCallToAction ActionArrowhttp://www.nutrakolusa.com/index.php?page_id=105
  • InfoBoxCallToAction ActionArrowhttp://eol.jsc.nasa.gov/earthobservatory/algaeingreatsaltlake.htm
  • InfoBoxCallToAction ActionArrowhttp://www.dailymail.co.uk/news/article-2239040/Crimson-tides-Tourists-flee-Bondi-Beach-Red-Sea-rare-algae-bloom-turns-water-colour-blood.html
  • InfoBoxCallToAction ActionArrowhttp://blogs.nature.com/news/2012/09/why-has-the-yangtze-river-turned-red.html
  • InfoBoxCallToAction ActionArrowhttp://www.atlasobscura.com/places/blood-falls