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This lecture is an online discussion organised under our new Scaling in Complex Systems lecture series. Under this new series, we shall hear from researchers investigating mechanisms of scaling, such as self-organized criticality, preferential processes, multiplicative processes and sample space reducing processes.

For the foreseeable future, lectures will remain predominantly online. 

Speaker Overview

Andrea Rinaldo is a Professor of hydrology and water resources at Ã‰cole Polytechnique Fédérale de Lausanne, Switzerland. As a prominent figure in the field of Ecohydrology, he has been admitted as a member of the National Academy of Sciences, the National Academy of Engineering, and the Royal Swedish Academy of Sciences. His research has led to the development of a theory of self-organized fractal river networks and of efficient transportation networks. Examples of his research include the study of the dynamic origins of form and function of river networks, bio-morphodynamics in tidal systems, the role of directional dispersal and river network structure on patterns of biodiversity in fluvial ecosystems. He has been presented with various awards including the Hydrologic Sciences Award from the American Geophysical Union, the Dalton Medal from the European Geosciences Union, and the Prince Sultan Abdulaziz International Water Prize from the Kingdom of Saudi Arabia. 

Abstract

Scaling provides a general framework for understanding general power-law behavior – the essence of scale-invariance of observable processes in nature -- and deducing relationships between processes. First, I will discuss why scaling theory can be used to develop a framework for the analysis of diverse empirical macroecological relationships traditionally treated as independent. The related mathematical arguments predict links between the species-area relationship, the relative species abundance and community size spectra in accord with empirical evidence. Second, I will address how finite size effects may cloud (and conversely reveal) scaling processes. Third, I will discuss emergent ideas, not yet fully verified experimentally, on the covariation patterns between size-dependent stochastic metabolic rates regulated by resource supply/demand in a variety of ecosystems across scales. Key to that is a scaling ansatz for the joint probability of phenotypes, including mass and metabolic rates, because fluctuations underlie the ecosystem consequences of resource utilization. My hypothesis is that natural systems, from cell cultures to marine microorganisms, from field-scale soil microbial ecosystems to forests, follow a general size-dependent scaling relation for resource use that accounts for the fluctuations inherent in the distributions of species’ attributes and stochastic drivers/controls affecting temperature and energies of activation. I shall comment on recent experiments, on research needs, and on our current understanding of fluctuations and covariations of metabolic rates and body mass in living organisms. If properly validated experimentally, this framework would generalize the iconic Kleiber’s law, purportedly holding over 21 orders of magnitude in organismic body sizes, and the related metabolic theories of ecology.

Meeting Details

There will be 45-min lecture from the speaker, followed by a 45-min Question & Answer session.

To attend the lecture, please click this  at 15:00 on Thursday 17th June 2021.

The event will be held via Zoom.