Entropy production as a driver for increased functioning of complex ecosystems

The Earth's climate is driven out of equilibrium by the incoming energy from the sun. This huge amount of energy, on average about 280 Watt/m2, not only determines dynamics of ocean and atmospheric currents, but uniquely on earth also the evolution of life, the emergence of ecosystems, and the rise of biodiversity. How stable is the current steady state on earth? Are there alternative states the system could accidentally switch to, especially when changing key parameters?

In this project, the student will investigate how entropy production determines (or is an consequence of) the complexity, stability, and functioning of species-species interaction networks with/without climatic forcing. One feasible approach would be to use simplified dynamical models from ecology and earth science with multi-stability. This will allow the student to study the stability of the steady states and their transitions in presence of intrinsic fluctuations. Specifically, close attention will be given to the influence of the steady state's underlying complexity on the stability, and the emergence of biological system function. Subsequently, the stability of the steady states (or fitness in biological systems) will be analyzed under changing external conditions (external, climatic forcing). Once relatively simple systems are understood, the student will be able to develop more realistic ecosystem models with climate forcing to make predictions about potentially catastrophic shifts in their behaviour. The models will be parameterized with real data from the global Biotraits database developed at ICL, which contains data on the individual-level physiology of thousands of species. The predictions, about the link between climatic forcing, entropy, complexity and functioning will be testable using new and burgeoning data from aquatic and terrestrial ecosystem experiments at Silwood Park as well as global datasets such as FluxNet.