Viruses and bacteria are everywhere. While we tend to think of viruses as something that makes us sick, they are actually found in every environment where there is life. That includes the ocean, geothermal pools, streams, and soil. In fact, viruses are the most abundant organisms on the planet, and while each gram of soil contains a huge number of bacteria, there are even more viruses. Even though we know they are there in huge numbers, its not clear what role they play in the ecosystem. I am interested in the interactions between the bacterial and viral communities in the soil, and the impact of environmental conditions on these communities. While there is much work on describing bacterial communities in different environments, there is less known about the viral communities and thus we are missing an important part of the picture.
I am using Winogradsky columns as a model microbial ecosystem to study the dynamics of bacterial and viral communities in the soil. A Winogradsky column is a soil bacterial enrichment culture. To make one, I collect sediment from a local pond and add it to an acrylic cylinder along with additional nutrient enrichments. Over a period of months, populations of microorganisms develop at different depths due to varying local conditions. The vast majority of these microorganisms cannot be cultured using laboratory media. The Winogradsky column is a fixture of undergraduate microbiology labs but the complexity and activities of the microbial community are poorly understood.
The Winogradsky column was developed over 100 years ago and was one of the first laboratory tools used to study bacterial ecology. I am putting it in a new role paired with cutting-edge technology to study viral ecology. With this approach I can investigate the environmental factors that govern the structure and dynamics of microbial communities and the role that viruses play in changing or establishing the community. The Winogradsky column has the potential to reveal immediate responses and longer term evolutionary change in viral and microbial populations to environmental change. Most research on this topic has been on marine ecosystems and relatively little is known about viruses in soil and sediment. Thus the pairing of the Winogradsky column with new technology as a model system to study viral ecology has the potential to make a significant impact on understanding the factors that govern soil microbial ecosystem function.