Dissolved Nutrients

IN BRIEF:

Peter Thorburn presented an overview of the dissolved nutrients section of the scientific consensus statement on the Great Barrier Reef, which he helped lead.

• The consensus statement reviewed nearly 1,300 studies on topics such as the sources, drivers, and management of dissolved nutrients impacting the Reef.
• The agricultural development of catchments, particularly sugarcane cultivation, has increased dissolved nitrogen and phosphorus exports by 1.5-3 times compared to pre-development levels.
• Reducing fertiliser application is the most effective and profitable practice for reducing dissolved nutrient exports, though there are uncertainties around the optimal application rates.
• The effectiveness of other management practices like irrigation and enhanced efficiency fertilisers is variable and not clearly demonstrated.
• Natural and near-natural wetlands have potential to retain and process dissolved nutrients, but there is limited evidence on their water quality efficacy and cost-effectiveness in Reef catchments.