The maintenance of habitability across multiple scales: A meta ecosystem view of Gaia

Abstract

The Gaia hypothesis postulates that life and the abiotic environment of planet Earth form a self-regulating system, capable of maintaining planetary habitability. Previous studies have highlighted mechanisms by which environmental regulation can emerge. The majority of prior work has modelled life-environment interactions at the level of organisms interacting with their local environment. The model presented in this thesis uses a meta ecosystems approach to look at not just how organisms interact with their environment but how ecosystems interact with each other and a shared global environment. It is hypothesised that interaction through a shared environment decreases the probability of ecosystem collapse within a world consisting of numerous ecosystems. To test this hypothesis a version of the flask model is used where numerous ecosystem flasks exist within a global flask and interact with a shared environment. It is found that when ecosystems are able to interact with, and through, a shared global environment the probability of ecosystem collapse is reduced. It is postulated that this is caused through a novel form of meta-ecosystem dynamics where, through interaction with a shared environment, ecosystems are able to affect one another's population and therefore likelihood of extinction. This appears to be another way, apart from regulation of abiotic factors and nutrient recycling, in which life environment feedbacks can affect the habitability of a global system.