Life at the Bottom of the Earth

I just found this article about scientific research on Lake Ellsworth in Antarctica. Really cool stuff (no pun intended). Contrary to popular opinion, the region is not dead or devoid of life. There is a lot of life beyond what you can see. And while the microbial life happens very slowly there, it still happens. The microbes just have to deal with some extreme stress issues (and bacteria, in general, are very good at doing that). Extreme cold, UV exposure, drying.

Many years ago I met a microbiologist by the name of Robie Vestal who spent some time there doing some microbiology research.

I’ve always loved the idea of the ecosystem he described living a few millimeters WITHIN rocks. Yup—actually inside sandstone. I couldn’t find a picture of the actual Antarctic rocks, but go to this site, scroll down to the third picture, and look at a similar rock found in Yellowstone National Park to get an idea of what such a layer would look like. When they cut into the rocks, there was this thin layer 1 – 10 millimeters inside it. When they looked at it in detail, they found a group of microorganisms inside there. It was a lichen—similar to those that you find on tree bark, or on rock surfaces, but this one lives inside Antarctic rocks.

Lichens are interesting because they are an example of mutualism in action. A lichen is 2 different organisms (sometimes more) living together in a mutually beneficial fashion. One component is a fungus, and the other is an alga or a bacterium. The alga or the bacterium within the lichen is photosynthetic, which means it gathers its energy from sunlight (just like green plants), and provides the primary energy in the system. The fungus lives off of the chemicals (metabolic products) made by the bacterium or alga. The fungus can soak up water better, providing that for the photosynthetic part of the lichen. The bacteria or algae cells live intertwined within the hyphae (hair like structures) made by the fungi.

The lichen takes up residence inside the Antarctic rocks probably because it’s just a little warmer and less dry than living on the surface of the rock. It grows VERY slowly, but it’s there and metabolically active.

NASA is very interested in biological research in Antarctica because it’s one of the few places on Earth that may hold relevance for finding life off of Earth. This is a field of research known as Exobiology. The idea is that if we can understand how microbes withstand extreme environments on our own world, then we may understand what sites to look at on other planets for life or the remnants of extinct life. And the water in the underground Lake Ellsworth is certainly an example of extreme stress. Futhermore, by studying life in extreme situations, we may get a better understanding of how life survived on the early Earth, when the conditions weren't as favorable as they are today.