REEForm Thematic Programme 1: Reef islands

Coral reef islands are coherent accumulations of carbonate sediment deposited directly on, or adjacent to, coral reef platforms. Reef islands are considered among the most vulnerable landforms on earth as they are generally small in size, low in elevation and are physically unstable to changes in environmental boundary conditions. This combination of factors has aroused international concern over the physical sensitivity of these landforms to catastrophic natural hazards, such as tsunami, and projected global climate change. Such international concerns are heightened in mid-ocean atoll nations where reef islands provide the only habitable land.

The prevailing perception of the future for reef islands is for widespread island erosion which may render atoll nations among the first environmental refugees of climate change. Such perceptions of island vulnerability are founded, however, on incomplete knowledge of the environmental controls on reef island evolution. Island formation is controlled by production of an abundant sediment supply and physical processes (waves and currents) that transport sediment to nodal locations on reefs. At longer timescales sea level change modulates the level of the process regime and broad patterning of coral reef development. However, significant gaps exist in our understanding of the relationships between these factors and the timescales of importance of each factor in controlling island development and change. These gaps in knowledge of reef island geomorphology seriously compromise our ability to accurately predict future reef island states and morphodynamic responses to changing marine and environmental baselines. The purpose of this research theme is to address gaps in understanding reef island formation and change in order to better resolve the future geomorphic trajectory of reef islands. In particular the theme will foster research in the following areas:

  • Process-based studies of island morphodynamics at seasonal, interdecadal and centennial timescales focussing on styles and rates of morphological change.
  • Improved spatial coverage of studies of island formation and change that encompass different reef regions.
  • Increasing understanding of the initiation and chronology of island formation and the interaction between island building and past sea levels
  • The importance of sediment production and the links between reef ecology, sediment supply, and how these vary temporally and influence styles of island formation.