NERP TE Project 5.3 Vulnerability of seagrass habitats in the GBR to flood plume impacts: light, nutrients and salinity (JCU)

The Reef Rescue Marine Monitoring Program (RRMMP) has identified that seagrass meadows along the Great Barrier Reef are in a state of decline. This project will undertake desktop analyses to quantify the exposure of seagrass meadows to flood plumes. Aquaria experiments will measure responses of seagrass to variation in light, nutrients and salinity. This project will also use use True Colour Remote sensing images, to derive flood plume exposure and relate to changes in seagrass abundance and composition. The results will be synthesised to define thresholds of concern of water quality impacts, with a particular focus on flood plumes, and input into the development of guidelines for the protection of seagrass meadows. Tasks include: 1. Quantifying the level of exposure of seagrass meadows to changes in water quality associated with flood plumes (using True Colour Remote sensing) in coastal regions of the GBR. 2. Measurement of changes in biological traits (e.g. growth, biomass) of seagrass in relation to water quality (Light, nutrients, salinity) determined by experimental studies. 3. Experimental testing of indicators of seagrass status adopted in the Great Barrier Reef Marine Monitoring Program (MMP) (e.g. nutrient ratios) in response to changes in water quality. 4. Experimental verification of water quality response models and thresholds, in particular in relation to the MMP.

Apart from the direct impact of tropical cyclones, declines in seagrass abundance and distribution can be attributed to decreasing water quality, particularly caused by the direct and indirect effect of sediments carried by flood plumes. Research on the interactive effects of changing light, nutrients and salinity levels on seagrasses is required to establish water quality thresholds in order to effectively manage and conserve these essential GBR habitats. The outcomes of the research will also help with the interpretation of the cause of changes in seagrass abundance, and therefore, management priorities.

Principal Investigator
Collier, Catherine, Dr TropWATER, James Cook University (TropWATER/JCU)

Publications / Data

Tags: marine