Coral Food Webs Under Stoichiometric Constraints

Coral reefs are one of the most important and critical ecosystems on the planet which serve as a backbone to oceanic biodiversity. Coral reefs are among the ecosystems that are facing the greatest challenges to their survival. Perhaps the most critical species are the corals themselves. Corals depend on symbiotic dinoflagellates called zooxanthellae which provide both carbon and essential nutrients to the coral.  Using the framework of Ecological Stoichiometry, the study of the balance of essential elements in ecological interactions, we develop and analyze a mathematical model of a coral food web. The model is an 11-dimensional system of ordinary differential equations that tracks the population dynamics of phytoplankton, zooplankton, zooxanthellae, coral, sponges, as well as the phosphorus in the environment and live and dead biomass. Our model aims to better understand the relationship between a few key reef species and to discover critical thresholds that determine the survival of the various species. We investigate how variations in light and nutrient levels affect population dynamics. The model explores key relationships, such as mutualism between zooxanthellae and coral and competition between coral and sponges. The model sheds light on critical factors influencing the biodiversity of coral reef food webs.