Many studies have shown that individual animal species impact elemental movement across landscapes. Scaling theory allows us to extrapolate these results from individual species to all species in an ecosystem over large distances and time periods. To scale movement of elements across landscapes by animals, we use body mass scaling of metabolic rate, day range, population density, home range, gut passage time and animal lifetime. These traits are each predictable to a variable degree with scaling theory. For instance, metabolic rate is highly scalable across vast body mass differences from microbes to whales (Kleiber's law) and metabolic scaling theory (MST) predicts this tight relationship based on constraints of how resources are allocated through bodies. Theory also predicts body mass relationships with other traits, such as home range, because larger animals need more space to support themselves than smaller animals. However, the theory does not go down to first principles where biological and ecological patterns can be explained with through the laws of physics like MST and predictability (r²) is lower. Here I explore whether predictions of zoogeochemistry can be integrated into MST or other earth system modelling frameworks enabling us to better quantify this important ecosystem service across both space and time.
