Three dimensional model of atoll hydrodynamics

The objectives of this paper were three-fold: (a) Develop a three-dimensional method of modelling hydrodynamics in and around atolls. (b) Establish physical processes of benthic shear velocity and shear stress as significant for habitat suitability of coral reefs. (c) Enrich morphological modelling detail in case of Rongelap atoll, for example. The last objective is still a work-in progress, but the present paper has provided a good review of atoll modelling methods and established our benthic shear velocity as a habitat suitability indicator, measured by a new tool: the “under water weather balloon”, which can be used by resource assessment surveyors to quantify the hydrodynamic climate at dive sites. Sound modelling methodology is a powerful tool that can answer many questions, such as what drives larval settlement in and around an isolated atoll and what would be the likely trajectories of sand, larvae, and anthropogenic pollutants. Hydrodynamic modelling may be useful to classify regions of an atoll’s sub-units on the basis of bathymetry and hydrodynamics to establish to direction and magnitude of bottom shear velocity, and to specifically empower resource managers to estimate the fate of effluent from aquaculture cages, for example