Digital mapping, visualization and wave-modelling technology is helping scientists predict the effect of rising sea levels at Lizard Island and other coral reef locations.
Scientists commenced work on the Australian Sea-Level Rise Project at Lizard Island in 2011. The team included Sarah Hamylton, Megan Saunders and Javier Leon-Patino. Over 4 million data points were derived from satellite, aerial and marine surveys. See J.X. Leon et al (2013). The results are summarized in Theme 2 of the Final Synthesis Report (PDF). LIRRF provided an initial grant for Sarah Hamylton’s research. It helped generate a serendipitous momentum, seeding the related research projects referred to in the Report.
This Global Change Institute video shows the digital model and how it was developed.
The model simulated two possible scenarios for the year 2100:
- Scenario A assumes a sea-level rise of 0.5m by 2100. Under this scenario, the reef flat which was previously exposed throughout the tidal cycle becomes permanently inundated and colonised by corals. Sand-dominated areas get progressively deeper. The coral grows vertically at a rate that keeps it close enough to the surface to avoid ‘drowning’ (i.e. decline and death of coral caused by increasing depth / reduced availability of light for photosynthesis).
- Scenario B assumes a total rise of 1.2m by 2100. It is illustrated in the 10 panels below. Shallow areas with a depth of less than 1.7m are shown in red. Areas with a depth greater than 27m are shown in green Under this scenario, the reef system grows through the first 30-40 years, causing the shallow areas to increase. Elevated features of the reefs become more pronounced. At approximately 2050, the sea-level rise begins to outpace coral growth by such a margin that the entire reef platform starts to drown. See S.M. Hamylton et al (2014).
The model is also helping scientists explore how rising sea levels will impact interdependent ecosystems, especially coral and seagrass. Coral reefs shelter lagoons from incoming waves, allowing seagrass meadows to thrive. The sea-level rise could result in larger, more energetic waves traversing the reefs, generating hostile conditions for seagrass. However, vertical growth in the protecting reefs could mitigate such hostility. See M.I Saunders et al (2014).
In this video, Sarah Hamylton discusses the technology she is using to map the Great Barrier Reef
This video by Megan Saunders & Javier Leon et al provides additional context.