Microbial communities play key roles in all ecosystems and are essential to many industries and processes, such as agriculture and sewage treatment. Researchers in the Ecosystems and Networks Integrated with Molecular Assemblies (ENIGMA) Scientific Focus Area, a multi-institutional program that is managed by Lawrence Berkeley National Laboratory (Berkeley Lab), have developed a framework to quantify microbial community resilience in the face of environmental changes.
The investigators hypothesized that members using gene regulation to cope with changing conditions in the environment would confer resilience to a microbial community when resources are in flux. 
In a study published March 20 in Molecular Ecosystems Biology, a team of researchers led by Nitin Baliga (pictured, left) of the Institute for Systems Biology (ISB) tested a sulfate-reducing bacterium, Desulfovibrio vulgaris, to undergo repeated shifts in living conditions to force it to be independent or form a mutualistic relationship with the hydrogen-consuming Methanococcus maripaludis.
Throughout the course of experiments, the microbial community became less and less proficient at recovering from the changes and would eventually collapse. 
However, making a single regulatory mutation in the bacterium could prevent this phenomenon. Researchers studied the mechanism for the collapse and determined the cause to be conditional gene regulation, which is the very feature that allows the microbial community to adapt. Baliga said, “What’s remarkable is that it was the frequency and not the quantity of environmental change that caused the microbial community to collapse. It goes to show how structure and dynamics of environmental change can have profound consequence on resilience of biological systems.”
Researchers developed a framework that will be invaluable for observing the behavior of microbial communities under simulations of current and projected environmental conditions. Their work will help scientists make predictions about the future of ecosystems and identify mechanisms to protect them. Read more on the ISB website.
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ENIGMA works on the fate and transport of contaminants with an emphasis on the basic questions that will inform future bioremediation efforts and general ecology/biology of the environment through understanding microbial biology and the impact of microbial communities on their ecosystems. ENIGMA – Ecosystems and Networks Integrated with Genes and Molecular Assemblies – is a multi-institutional project funded by the U.S. Department of Energy (DOE) through its Scientific Focus Area (SFA) grant program and managed by DOE’s Lawrence Berkeley National Laboratory (Berkeley Lab). Read more at http://enigma.lbl.gov/
