A microbial game of thrones - from theory to application

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Bacteria are tiny microbes, typically a hundred times smaller than the width of a human hair, but together they still make up a large part of all living matter on Earth. They are also largely responsible for the cycling of the chemical elements on our planet. They are a key component in understanding the consequences of global warming – brought about mainly by fossil fuel burning. At the molecular level, bacteria display much more biodiversity than animals or plants. In natural ecosystems they form highly complex and dynamic communities. The ecology of these communities has so far defied the development of functional theory that can be used to understand the cycling of the elements in nature, or to rationally design bacterial communities to do useful things like production of renewable energy to mitigate global change. Two competing ecological perspectives are known as “niche” and “neutral” theory. The “niche” perspective holds that each bacterium has its proper place in nature and will outperform its competitors when the environment favours its specific properties. The “neutral” perspective holds that many different species have similar properties and the ecological success of any single species is determined by chance processes. However, neither perspective can explain general observations that microbial communities are dominated by only a handful of bacteria (consistent with “niche” theory) yet show apparently random turnover of these winners (the microbial game of thrones, consistent with “neutral” theory). Adopting concepts from the economical sciences, the proposed research investigates whether the “niche” and “neutral” perspectives can be unified into an overarching theory for microbial ecology that can explain those general observations. My central premise is that in microbial ecology there exists a positive relationship between population size and ecological fitness, brought about by micro-evolution on short timescales. This premise is analogous to the positive relationship between wealth and returns on wealth, that economists use to explain the very high inequality in wealth distributions. This NSERC discovery research aims to generate experimental support for this new theory – and to apply it, by contributing to a robust and cost-effective process for renewable bio-energy production. The program's team will perform long-term continuous cultivation of microbial communities under stable conditions, while monitoring population dynamics with next generation DNA sequencing technology. Together, these approaches enable me to assess potential fitness benefits associated with newly evolved biodiversity. If successful, the research will make a groundbreaking contribution to microbial ecology and contribute to a real-world problem of high societal relevance - an economically feasible process for sustainable energy production.