8 December 2013 An Entry From Dr. Egbert Schwartz

I am a soil microbiologist. A microbiologist studies very small (micro) organisms. Soil is full of them; there could be more than a billion microorganisms in a thimble full of soil but they are so small you can’t see them with your eyes. What has surprised us is how many different types of microorganisms there are in soil. Most of them remain unknown to us and the only reason we know they exist is because we have detected their DNA. DNA is a large biomolecule that contains the information on how to put an organism together. Because a human is put together differently from a plant or a bacteria it is possible to determine if a DNA molecule is part of a human or a plant or a bacteria. And so we know that there are all these different kinds of DNA molecules in soil, that belong to bacteria, archaea, fungi, nematodes or protozoa, all of which are microorganisms. But most of these organisms we have never isolated or grown in a culture, so we don’t really know what they look like or what they do. I have had to go to school for many years after high school to learn how to study microorganisms by, for instance, analyzing their DNA. Now I am a professor in the Biology department at Northern Arizona University.

We are now studying the microorganisms in the soils of the McMurdo Dry Valleys in Antarctica. This is a very cold place and though there is plenty of water around it is all frozen into big glaciers and ice or snow. So the soils are actually pretty dry like a very cold desert. There are not very many microorganisms in the soil here but we have found their DNA molecules here too. But because it is so cold here we are not sure if all these microorganisms actually grow here or if they just blew in from another continent on the dust. And so we are trying to discover if new DNA molecules that belong to microorganisms are made here in the soils. If new DNA molecules were made it would mean that the microorganisms actually grow here and that they like living in the soil of the McMurdo Dry Valles soils. Our first results show that new DNA molecules are made in the Dry Valley soils and we have been able to identify to which microorganisms the DNA belongs. Now we are trying to figure out where in the Dry Valley soils the mciroorganisms like to grow and what kind of food they like. Do they grow under the rocks? Do they feed on microorganisms that grow in the lakes? We are hoping to find out.