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Fri, 12 Aug 2016

Tracking sediment from catchment to the reef

Burdekin in flood
The Burdekin River in flood

A James Cook University scientist is investigating the origin of sediment that ends up on the Great Barrier Reef – research that could lead to improved water quality on the GBR.

Dr Zoe Bainbridge has received an Advance Queensland early-career fellowship to investigate the sources, transformation and dispersal of fine sediments that can damage the health of inshore reef and seagrass ecosystems.

Dr Bainbridge, who will be based at TropWATER at James Cook University in Townsville, will use her three-year fellowship to expand on her recently completed doctoral thesis, in which she investigated the sources of fine sediment posing a threat to the health of the Great Barrier Reef.

“Of the sediments that travel from our rivers to the reef, the fine-grained particles pose the greatest threat to the health of coral reef and seagrass ecosystems, because they have an increased capacity to be transported much further offshore as well as transport other pollutants.”  

“They also stay in suspension longer and so suppress light conditions over considerable periods of time,” Dr Bainbridge said.

The project focuses on the Burdekin catchment, which covers 133,000 km2 and is the largest single source of sediment that flows to the Great Barrier Reef.

“Finding the source of these fine sediments allows focused remediation efforts by Australian and Queensland government reef programs where they’re most needed,” Dr Bainbridge said.  

“By reducing these pressures that we have some control over, we can help make the reef more resilient to other threats.”

Dr Bainbridge also plans to tackle a key challenge facing scientists who investigate sediment in the marine environment: significant changes that occur to the properties of sediment during the journey from the river mouth to reef, making it more difficult to trace and identify their sources.

“The process is called fractionation, and it can change the geochemical and physical properties of sediment, which are important clues as to where the sediment came from,” she said.

Dr Bainbridge will be supervised by Dr Stephen Lewis (TropWATER, JCU) and Prof Jon Olley (Griffith University). “We are very excited to have Zoe back in Queensland” Dr Lewis said. “She has excellent rapport with industry stakeholders and farmers in the region who have been working with her on sediment erosion issues. This project will help us better prioritise erosion hotspots in the Burdekin catchment so we will get a better outcome for the reef.”

While most sediment tracing studies have been limited to a single technique, Dr Bainbridge aims to combine several techniques and, uniquely, will work from the catchment to the Great Barrier Reef.

“By refining the ways we track fine sediment, and by investigating just how the sediments change as they travel, we hope to develop techniques that can be used in other catchment-to-reef studies in Australia and internationally,” Dr Bainbridge said.

TropWATER at JCU and the National Environmental Science Programme Tropical Water Quality Hub will match her Advance Queensland Research Fellowship funds of $180,000 over three years. The project involves collaboration with the Australian Rivers Institute (Griffith University), CSIRO, North Queensland Dry Tropics and the Queensland State Government.

Link to pics: http://bit.ly/2aKp8re


Dr Zoe Bainbridge
E: zoe.bainbridge@jcu.edu.au