Total light exposure affects coral growth rates

Research has shed new light on how interruptions to benthic photosynthetically active radiation (bPAR) – the amount of usable light reaching the seafloor – affects the health and growth of corals. Dr Barbara Robson at the Australian Institute of Marine Science leads NESP TWQ Project 5.3, which conducts experiments at the SeaSim facility on the effects of light deprivation on coral species. In a recent webinar Dr Robson discussed how total cumulative bPAR over the course of a day is the main light-related factor affecting coral growth, regardless of how varied the delivery of that light is. This means even short interruptions to light levels (for example, sediment shading during a flood plume) can negatively affect the growth rate of corals common to the Great Barrier Reef. These results have been combined with satellite-derived bPAR maps to create water quality models, which will allow scientists to track how varying river sediment loads affect water quality across the Great Barrier Reef year to year and assign a letter grading that can be used in Reef Report Cards. Collaborators are looking into whether bPAR maps can be used to predict coral and seagrass health and community composition in different parts of the Great Barrier Reef. Read more in the factsheets (here and here).


Photo: Sam Noonan, AIMS