Section 5

Table of Contents

Section 7


6. Diffusion-limited growth of sponges

A variant of the diffusion-limited growth model was proposed by Kaandorp [Kaa1992, Kaa1994] to simulate the growth of marine sessile organisms; namely corals and sponges.

Both types of organisms develop by adding successive layers to the structure formed so far (growth by accretion). The layer size is determined locally by the availability of nutrients that diffuse in the water surrounding the organism.

In proximity to regions of the organism that have high curvature, the gradient of nutrient concentration is high, and the structure grows fast. Near flattened areas the gradient of the concentration is lower, and the structure develops more slowly. Consequently, a dip may occur near the center of a flattened area, causing the emergence of a pair of new branches. The development of a hypothetical sponge simulated using this technique is shown in Animation 2.