Ecological science from cells to ecosystems and human well-being
How do living systems change in changing environments?
What do these changes mean for human well-being?
Understanding our changing biosphere requires connecting our fragmented knowledge of biological process across scales. Our research advances a solution to this challenge by studying the processes that unite all of life on Earth – the metabolic processes by which living systems uptake, store and convert energy, matter and information from their environments to grow and persist.
Seafood biodiversity and human health
For many of the world’s seven billion people, food security is a benefit provided by aquatic ecosystems, and a large variety of wild species are still consumed even though biodiversity is declining worldwide. We use biodiversity-ecosystem functioning theory to test whether biodiversity directly enhances nutritional benefits at global and local scales, by collating and synthesizing nutritional traits of 801 aquatic species. We found that it does, particularly for essential micronutrients, such as calcium and zinc, with the potential to combat the problem of micronutrient deficiencies (‘hidden hunger’) in coastal communities.
Bernhardt, J.R. and M.I. O’Connor. Aquatic biodiversity enhances multiple nutritional benefits to humans. 2021. Proceedings of the National Academy of Sciences.
Evolution of metabolic traits
A major challenge for ecology and evolution is to understand how biodiversity is maintained despite the tendency for competition to select for a single best competitor. The strength of competition is a key determinant of biodiversity, and may thereby impact ecosystem functioning. While it is well known that evolution can drive character displacement when species compete for nutritionally substitutable resources, we still do not know what facilitates or constrains adaptation of resource competition traits when limiting resources are non-substitutable (as in essential nutrients). Using a combination of experimental evolution, whole-genome re-sequencing, and competition experiments, we demonstrated that rapid evolution of metabolic traits (e.g. minimum resource requirements, R*) can alter competitive outcomes on ecological timescales and that improvements in resource requirements for different resources were positively associated (i.e. no detectable trade-offs), possibly owing to common metabolic pathways associated with essential resources.
Bernhardt, J.R., Kratina, P, Pereira, A, Tamminen, M., Thomas, M.K.T, and A. Narwani, 2020. The evolution of competitive ability for essential resources. Philosophical Transactions of the Royal Society B. [code and data]
Scaling individual metabolism to populations and communities
The temperature dependence of highly conserved subcellular metabolic systems affects ecological patterns and processes across scales, from organisms to ecosystems. However, a major gap in our knowledge of how temperature-dependent subcellular metabolism may constrain higher level ecological processes has been at the level of populations. Using theory and experiments, we performed the first critical test of the hypothesis that temperature effects on subcellular metabolism constrain the dynamics of populations and their equilibrium abundance, making a fundamental advance in our understanding of how metabolic constraints shape population responses to changing environments.
Bernhardt, J.R., Sunday, J.M. and M.I. O’Connor, 2018. Metabolic theory and the temperature-size rule explain the temperature dependence of population carrying capacity. The American Naturalist. [data]
Life in fluctuating environments
A major unknown dimension of global change is how environmental change is altering the informational milieu of living systems. Many organisms maintain steady internal conditions required for physiological functioning through feedback mechanisms that allow internal conditions to remain near a set point. However, living systems, ranging from phytoplankton cells to trees, persist in fluctuating environments not only by responding to change after it has occurred, but also by anticipating change through a variety of ecological and evolutionary cue and signal-based mechanisms. These feedforward mechanisms, in contrast to feedback mechanisms, allow biological systems to prepare or prime themselves for environmental change so that they can adaptively buffer or exploit expected environmental change.
Bernhardt, J.R., O’Connor, M.I., Sunday, J.M and A. Gonzalez. Life in fluctuating environments. 2020. Philosophical Transactions of the Royal Society B. [code and data]
Bernhardt, J.R., Sunday, J.M., Thompson, P.L. and M.I. O’Connor 2018. Nonlinear averaging of thermal experience predicts population growth rates in a thermally variable environment. Proceedings of the Royal Society B. [data][code]
