A trait-based model of coral-algae symbiosis to study the adaptative dynamics of coral-algae symbiosis. The model assumes that only the corals adapt to maintain the symbiotic relationship because corals controls the fluxes of nutrients through various processes and the algal growth is highly regulated. In the model, the algae biomass is assumed to be proportional to the coral biomass. The symbiont to coral biomass ratio (S:C) is considered as a parameter.
Coral adaptation to symbiosis is captured by assuming that the temporal dynamics of a physiological trait, reflecting the energy that corals invest in the symbiotic relationship, is proportional to the gradient of coral fitness (assumed equal to net coral growth).
The result shows that the survival range of the coral-algae symbiosis depends on the symbiont to coral biomass ratio and the cost of symbiosis. When the cost of symbiosis, then the coral-algae complex can thrive for a broad range of symbiont to host biomass ratio. This survival range narrows down as the cost of symbiosis increases.
The python code Ms1-Model.py reproduces all the figures that are published in the manuscript bellow.
N. A. Raharinirina, G. Brandt, and A. Merico. A trait-based model for describing the adaptive dynamics of coral-algae symbiosis. Frontiers in Ecology and Evolution, 5:31, 2017.