Do complex water movement patterns around reefs cause settlement, biodiversity or productivity hotspots? (C3.5S)

Task leader: Ms Janelle Eagle, CRC Reef and James Cook University.

Task associate: Dr Peter Doherty, Australian Institute of Marine Science

Patterns of water movement around coral reefs are largely influenced by reef shape, and this topographically driven water movement is known to modify the distribution patterns of plankton and the pelagic larvae of coral reef organisms. If predictable patterns of water movement occur regularly under particular sets of physical conditions, it is possible that the structure and dynamics of coral reef assemblages adjacent to topographic features may be affected. For example, the tendency for zooplankton to accumulate in areas downstream of islands and reefs may lead to increased food availability or settlement of larvae in these areas, which may subsequently lead to higher productivity or biodiversity. Despite the implications of these patterns for marine reserve design, they have not yet been examined in a holistic context.

This project is a multi-disciplinary study that examines the role of complex water movement patterns at an around reef scale on adjacent coral reef assemblages. Three main hypotheses will be investigated: (1) The interaction of reef topography, tidal flux and wind exposure produces water movement patterns that affect the distribution patterns of plankton and the larvae of coral reef organisms around a reef; (2) Water movement patterns lead to variation in rates of larval settlement among reef areas; (3) Water movement patterns lead to differences in the species diversity and population dynamics of coral reef assemblages among reef areas.