Sedimentary architecture and evolution of Halimeda bioherms in the Great Barrier Reef

The calcareous green alga Halimeda is a major contributor to inter-reef carbonate sediment deposits along the entire northern Great Barrier Reef. Built up over millennial timescales, the Halimeda bioherms are the most extensive, actively accumulating Halimeda deposits in the world. These deposits extend back to the pre-Holocene, preserving evidence of global climate change, glaciations and sea level changes, often prior to coral colonisation as the earlier Holocene conditions were more conducive to the growth of Halimeda than coral. Halimeda bioherms are therefore particularly important for understanding the history of reef development in the Great Barrier Reef.

This multi-disciplinary research project builds on earlier seabed mapping work, and investigates

  • the spatial distribution and morphological variation of the Halimeda bioherms
  • their relationship to the surrounding undersea landscape (channels, passages, and submarine canyons) and key oceanographic processes
  • new 3D models explaining their origin and development on the northern continental shelf, and
  • their importance as modern, structurally complex inter-reef benthic habitat, supporting ecosystem function and biodiversity in the northern Great Barrier Reef.

Project supervisor: Dr Luke Nothdurft
Associate supervisor: Dr Jody Webster


Image credit: Dr Emma Kennedy

Chief Investigators

Underwater photograph of Halimeda bioherms taken by Dr Emma Kennedy