At the sharp end of reef science

A woman whose research just might help preserve the world’s imperilled reefs has been obsessed with the ocean ever since she can remember.

After growing up as ‘a beach girl’ on the coast of northern New South Wales, Tracy Ainsworth moved to Townsville, Queensland, to study marine biology and aquaculture at James Cook University. She completed a PhD at the University of Queensland in 2008, investigating microbial communities associated with coral suffering disease and stress.

Her innovative research, which investigates whether bacteria, as well as algae, play a significant part in the life of coral, has determined that coral bleaching is a far more complex process than previously believed. Her work has attracted significant international attention, prompting invitations to present her research, undertake further research and be involved in postgraduate teaching at universities around the world.

“Coral reefs are beautiful, diverse, amazing structures and arguably the most beautiful places on earth,” says Ainsworth. “They can range from small areas to massive structures that compare in size to anything humans have managed to build. They are found in environments from the cold, dark depths of the ocean to shallow tropical waters. And all of this is achieved by a coral polyp – a simple basal organism – predominantly in symbiosis with single-celled algae. In surface reefs, the polyps provide algae with a home in return for the sugars created from its photosynthesis. How so much is achieved with so little fascinates me.”

But those amazing structures, which provide habitats for countless species and contribute trillions of dollars to the global economy, are under increasing threat. “Global and ocean warming is occurring and it is negatively impacting our reef systems. Coral reefs in Australia, and worldwide, have been significantly impacted by a myriad of local and global stressors, which are driving them towards collapse,” warns Ainsworth.

In order to save the world’s reefs it is first necessary to understand how coral functions, something that marine science knows surprisingly little about. For example, it had long been believed that the annual summer coral bleaching in the Mediterranean was due to bacteria. But during a six-month stint at Israel’s Tel Aviv and Haifa universities, Ainsworth proved bacteria wasn’t responsible and hypothesised that a range of environmental and physiological changes were causing the bleaching.

“That was important because it demonstrated that a reef system can change rapidly,” says Ainsworth. “Bacterial drivers may have been involved in previous bleaching events but removing that bacteria didn’t prevent the bleaching event happening. That suggests that there’s no single treatment to protect reefs and that they are complex systems where a single change can result in a myriad of responses happening at any one time.”

Ainsworth’s ongoing research has led to a greater appreciation of the complexity of the interactions that create and animate coral. “My research aims to understand the responses of the coral as whole – animal, algae, microbial consortia – to subtle changes in the environmental conditions and to determine how each component of the system can contribute to long-term health and survival of the reef system.”

But can unlocking these secrets help save the world’s reefs? Ainsworth is cautiously optimistic. “Australian institutions are leading the world in marine research and we are lucky to have internationally renowned researchers working here on improving our understanding and management of reef systems. I do think real-world solutions can be derived from the work myself and others are doing in this area. For example, my work on pre-bleaching stress responses in coral highlights the need to manage stresses long before we see bleaching occurring.

Bleaching indicates the algae have abandoned the coral polyp, and it used to be conventional wisdom that didn’t happen until water temperature reached about 32°C. I discovered that the symbiotic relationship coral has with algae and bacteria begins to break down at temperatures below 30°C. But it has to be realised that coral reefs are massive structures and single treatments are not necessarily logistically possible. Our best hope is to reduce the stress events and aim to provide the best possible environment to aid their recovery at key times.”

If there’s one thing Ainsworth is more passionate about than researching coral, it’s raising public awareness about its ecological, economic and aesthetic significance. “Reefs are extremely important to human populations, and not just as habitats for our fisheries or large contributors to tourism revenue. They show us the beauty and phenomenal capacity of the natural world. So we have an obligation to ensure that future generations are able to benefit from, and marvel at, these systems,” she says.