MARINE NURSERIES FORMED BY EDIACARAN FRONDS

Modern seagrass communities can induce canopy flow, where water flow within the seagrass canopy is slowed relative to the flow above. This creates a nursery habitat, providing shelter for juvenile animals. It was previously hypothesized that Ediacaran rangeomorph communities engendered canopy flow, and so we evaluate the possibility that these communities acted as nurseries by slowing water flow within the canopy. To address this, we constructed 3-D models of frondose organisms with varying levels of morphological detail, which were used in computer simulations of water flow (computational fluid dynamics, or CFD). The results allow us to establish the minimum level of anatomical complexity that needs to be represented in individual models in order to accurately reconstruct patterns of fluid flow. In addition, our simulations shed further light on the feasibility of osmotrophy in frondose Ediacaran organisms. These data provide the starting point for large-scale CFD simulations of flow around communities of Ediacaran fronds, revealing the extent to which these communities induce canopy flow and hence whether they would have been effective nursery habitats.