How wetlands help improve the water quality of the Great Barrier Reef
A Griffith researcher has teamed up with the Department of Environment and Science to test the role wetlands play in improving the water quality of the Great Barrier Reef—something that had previously not been done.
Dr Fernanda Adame, from Griffith’s Australian Rivers Institute, started working with the Wetlands Team at the Department of Environment and Sciences in 2017 as part of an Advance Queensland Fellowship. Together, they have developed a project to address the reef’s long-term health.
For the past century, catchment deforestation and agriculture intensification have increased nutrient and sediment runoff into the reef. As a result, poor water quality has caused excess algal growth, low light penetration, and sedimentation, resulting in the degradation of seagrass and coral reefs.
The Australian and Queensland Government’s have invested heavily in implementing on-farm best management practices, such as changing the timing and decreasing the quantity of fertiliser application. However, these changes will not be enough to address this problem.
The researchers conducted field campaigns to test how nitrogen moves through wetlands and is reduced by plant consumption and a bacterial process called denitrification, which transforms nitrate into nitrogen gas.
Engagement activities were also staged, such as an art-science collaboration where Traditional Owners, farmers and tourist operators expressed their views and what they considered valuable in their wetlands.
The team discovered that some wetlands were highly efficient at removing nitrate, the highest priority form of nitrogen. For instance, in catchments with extensive wetlands, over 50% of the nitrate moving through them was removed during a moderate flood. These results highlighted how natural wetlands provide a valuable ecosystem service in the Great Barrier Reef.
The researchers also found that constructed wetlands designed to mimic natural wetlands were a viable solution to the nitrogen problem of the reef. Dr Adame and her team worked alongside farmers to design drains that could effectively act as constructed wetlands, thus finding a practical solution to reduce agricultural impact downstream. As a result, wetlands are now included in the state policy for improving the Great Barrier Reef’s health.
Dr Adame provided significant input to the Scientific Consensus Statement and the Reef Water Quality Plan (2017), placing a focus on wetlands and driving significant environmental impact. Since then, several constructed treatment wetlands have been created, and dozens wetland restoration projects all over Queensland are now underway. The research provided a cost-effective solution for a long-debated problem, contributing to improving the resilience of the Great Barrier Reef.
“Natural wetlands play a major part in water quality improvement when appropriately managed, and constructed wetlands can provide a cost-effective solution for improving the water quality of the Great Barrier Reef. They can keep our waterways clean, while also providing numerous benefits such as biodiversity and flood regulation- there is not much to lose when investing in conserving, managing and restoring wetlands.”
Dr Fernanda Adame
Advance Queensland Senior Research Fellow of the Australian Rivers Institute.