Abstract: The diversity of life has drawn the attention of biologists for centuries. Yet there is still considerable debate about the mechanisms responsible for generating and constraining the distribution of such diversity. The quest for resources poses important limitations to how life can be organised, and because food production and consumption are ultimately physical processes of mass and energy balance, all organisms are constrained by how much energy they need and how much the surrounding environment can provide. Therefore, theories that express resource uptake and allocation on the basis of universal currencies have promising potential to integrate biological phenomena across scales. I will talk about how the energetic expenditure of an individual can effect processes across populations, communities and ecosystems. For that, I use the Metabolic Theory of Ecology (MTE) as an approach, which is grounded on first principles of physics and chemistry. Particularly, I explore how body mass and temperature: (1) determine metabolic and growth rates of individuals; (2) constrain abundances of populations across different trophic categories in conjunction with species richness and area; (3) limit, together with net primary production, biomass and the energy flux of different communities and (4) affect he energy transfer between different trophic levels within an ecosystem. I use fishes as models because they encompass the highest species richness among vertebrates, with > 7 orders of magnitude in body mass, occupying diverse habitats that vary substantially in thermal regime across the globe. In so doing, I discuss insights obtained from this theoretical approach, current limitations, their relevance to coral reef macroecology, climate change biology and future avenues for research.

Bio: Diego Barneche recently completed his PhD in the Quantitative Ecology & Evolution Group at Macquarie University. He is passionate about making better use of mathematical, statistical and computational tools to develop predictive ecological theories, models and empirical tests. He is currently interested in explaining mechanistically how individual-level determinants of metabolism affect the energy flux and productivity of populations, communities and ecosystems across the world’s oceans.