Simulating Coral Reef Evolution

The fundamental goal is to develop a simulation capability for the purpose of examining how changing conditions might affect the growth of a reef. The parameterizations for this effort were developed based on transects of the Great Barrier Reef. This simulation begins 21,000 years ago, at the end of the last ice age.

Over time, the continental shelfs flooded, thus creating more habitat for coral reefs, which flourished. The animation shows the temporal and coral-form evolution of the reef over time. Corals play an important role in the carbon cycle and there are quite a number of interesting ideas about possible roles they may have played in the global climate.

One hypothesis is that shallow-water carbonate systems may have accounted for a big change of the CO2 seen in ice cores, corresponding to the period since the last ice age. There is also the possibility of a positive feedback loop: sea-level rises providing more habitat for coral reefs, the reefs flourish and produce more CO2, the additional CO2 causes additional temperature increase and sea-levels rise even more. It is an interesting point that coral reefs were once an important source of CO2 released into the atmosphere, but now they account for only 1-2% of human-generated CO2.

In any event, one of the ideas central to this work is that if we can successfully simulate how reefs grew since the last ice age, we may be able to predict their evolution in the context of global change. Global Earth System Models include vegetation models and, in the future, the inclusion of a variety of ecosystem components will probably constitute a very active and important area of research. A coral reef simulation such as the one described here could be coupled with a global model to measure its response to changing climate conditions, such as those produced by greenhouse-gas forcing.

Ultimately, such a simulation could both respond and provide feedback to the overall system. About the Visualizations Data from the Kleypas Coral Reef Simulation was processed to create a 3-dimensional dataset representing 210 timesteps of 100 years of topography, sea-level, and coral reef composition.

• Bathymettry: Shown in gray, this is the ocean floor upon which the coral polyps build the "reef".
• Coral Forms: There are ten different "coral forms" managed by the simulation. An individual coral form is a coral group that has been classified by its basic form and response to various forcing functions. Each coral form is represented by a different color.