Near the southern region of the Great Barrier Reef (GBR), the Fitzroy River enters to ocean. The river is well known for dispensing sediment in huge brown plumes that swirl out to sea, affecting the natural environment and tourism in the area.
Aside from changing the blue coastal waters in Keppel Bay into a murky brown that reduces visibility, the sediment causes problems deeper down. It blocks essential sunlight from reaching marine plant life like seagrass.
Dr Nagur Cherukuru, our Senior Research Scientist, said this restricts growth of the seagrass, which needs the sunlight for photosynthesis.
“In addition, the light feeds phytoplankton as it passes through the water column. So the sediment also reduces this, making the area less biologically productive," Nagur said.
The Southern Great Barrier Reef is home to a colourful array of fish and other sea life, which draws tourists from across the globe. This marine life plays a vital role in a vibrant reef ecosystem and requires the sea grasses and phytoplankton.
It's not only sediment that gets washed out to sea. Dissolved organic carbon gets picked up by the river and washed out, impacting the carbon exchange between the land and ocean.
“Imagine phytoplankton photosynthesising in the ocean much like plants do on land,” Nagur said.
“This helps remove carbon dioxide from the atmosphere. When dissolved organic carbon blocks the light that phytoplankton need for photosynthesis, it reduces this process.”
Meanwhile, other measurable parameters like chlorophyll levels in the water can be indicative of a potential algal bloom.
"Harmful algal blooms can be devastating for marine ecosystems when they produce toxins that can cause health problems and even kill fish," he said.
Watching from the sea and skies
Due to this exchange between land and sea, where the Fitzroy River meets the sea at Keppel Bay on Darumbal Sea Country is a prime location to test our new AquaWatch Australia Mission. This Mission aims to develop a “weather service” for water quality.
We've installed two state-of-the-art HydraSpectra sensors so far, one on the river and another out in the bay. We'll be testing the AquaWatch system for monitoring of sediment and dissolved organic carbon flows from land to sea. The two on-water sensors will feed data into a centralised data hub, where it can be collated along with satellite data from space.
"It’s the technology that allows you to navigate using GPS, get a weather update or find out about bushfires near you," Alex said.
“Using hyperspectral imaging to measure the colours in the water, Earth observation satellites can give us water quality information over a huge area. But the on-water sensors are important for validating what we see from space and ensuring accuracy of the data, as well as providing more regular updates than we get from satellite data."
"Together, these two data sets can be incorporated into data models and processed with artificial intelligence (AI) to give us near real-time monitoring and even forecasts of water quality up to a few days ahead.”
Turning data into impact
As our scientists test the system at the GBR pilot site, we’re also exploring how to deliver water quality data to the people who need it to inform their water management decisions.
For example, understanding how much sediment there is, and where exactly it’s coming from along the river, can help direct actions to mitigate agricultural runoff or manage the integrity of riverbanks. AquaWatch can also be used to measure the success of any land and water management decisions in terms of water quality outcomes.
The hope is for AquaWatch to deliver the kind of reporting and forecasting that can be used to improve water quality, starting with pilot sites like the GBR and expanding across the whole country in the coming years.
As part of this process, an AquaWatch Community of Practice is being established for water managers, scientists, Traditional Owners and partners to learn more about AquaWatch and how to engage with us at the development stage.
We’re also looking for partners who want to co-invest and help us build the system. Our partners benefit from early access to data and have a chance to co-design for their purposes.