Researchers at Lund University in Sweden have invented new systems to study the life of microorganisms in the ground. Without any digging, the researchers are able use microchips to see and analyse an invisible world that is filled with more species than any other ecosystem.
Under our feet there is life and movement. In a spoonful of soil there are more microorganisms (fungi and bacteria) than there are people on Earth. At the same time, it is also an invisible world that is often difficult and impenetrable for researchers.
"Our soil chips could revolutionise how we study microbiological processes in the ground. Finally, we can follow what actually happens down the ground under a microscope in real-time", says Edith Hammer, associate senior lecturer the Department of Biology in Lund.
For a long time, experiments using petri dishes and real soil have been the traditional way of exploring life in the ground. What the researchers now have done is to create models of soil structures and ecosystems in microchips. With these, the researchers can study the life that takes place in the labyrinth systems of the soil - systems which they are now able to build on the same scale as the microorganisms themselves.
Using a technology called microfluidics, the researchers can produce relatively realistic soil models. The models are made of a silicone polymer and simulate the structure of the soil with components of organic and inorganic material, mazelike passageways, water and unevenly distributed nutrients on which the microorganisms feed.
"Our systems are transparent - this is probably what fascinates people the most. It allows us to look directly at all processes and behaviours in the ground. We see how the microorganisms move, search for food, choose where they are going and how they compete with each other, but also cooperate", says Edith Hammer.
"The microorganisms are ecosystem engineers. We see how they change their environment by creating or blocking passageways with their cells. The bacteria in the soil tunnel system have to fight hard against the forces of water to move at all", she says.
The researchers are convinced that the method will increase knowledge of the structures in the soil and the importance of the organisms living there. Eventually, this will lead to better recommendations for how to use soil in a sustainable way that preserves the ground's functions.
The new microchips were developed in collaboration between biologists and engineers at the faculties of science and engineering in Lund, together with their colleagues in Amsterdam.
The ISME Journal