The Suess Glacier melts to form Lake Chad. Click to enlarge .

A Taste of Life in a Dry Valley

January 11 , 2002

There is little to smell or taste when hiking through the Dry Valleys of Antarctica. The air, water, ice and rock give off few molecules detectable by the human taste buds or nose. But, lack of smell or taste in water does not mean that it is safe to drink, as the men in Scott's expedition discovered when they drank the water of Lake Chad in the Taylor Dry Valley. This is the story of how they came to name this lake, as told to me by Dr. John Priscu, and expert on the native life in the Dry Valleys.

Lake Hoare is down the valley from Lake Chad. The water bottle I had with me was filled with water pumped and filtered from Lake Hoare, water that tasted clean cool and refreshing. Lake Chad probably tasted just as good to Scott's men.

	Lump of Cyanobacteria on the shores of Lake Chad. Click to enlarge .

However, as I walked along the shore of lake Chad, I spotted something very strange; a pile of brown stuff about the size and thickness of a cow patty. It was wet, brown and had thin fibrous layers. I had hiked for days in the Dry Valleys and seen no life, and yet this looked like a living mass. After I returned to McMurdo, I showed a picture of the brown mass to Dr. Priscu, and he immediately identified it as cyanobacteria. He said that the brown coloration was pigment to protect it against ultraviolet light, and that it made antifreeze to give it some protection against freezing and also released toxins into the lake water.

Looking at the image, I felt as If I had traveled back in time a billion years to witness the origin of life on earth. This lump of brown sitting on the wet ground of the Antarctic was, to the human eye, the apparent ruler of this domain. Not even a single blade of grass added greenery to this landscape.

Scott and his men ingested the cyanobacterial toxins along with the lake water. It gave them diarrhea and caused them to use vast quantities of toilet paper. The brand name of the toilet paper was Chad, and so, the lake acquired a name.

The lesson that you cannot tell the safety of a water supply by smell or taste is a good one that applies just as much in California as it does in Antarctica. But there is so little life in Antarctica that an undrinkable lake is a rare surprise.

field notes