Research investigates role of coral rubble in reef ecology

QUT PhD researcher Tanya Dodgen, from the School of Earth & Atmospheric Sciences, is conducting an experiment on the Great Barrier Reef looking at ways to deal with areas of coral rubble.

Coral reefs – such as the Great Barrier Reef – are facing increasing challenges due to climate change and human activities.

The focus of Tanya Dodgen’s PhD is on one aspect of coral reefs: coral rubble. With an aim to better understand its role in reef ecology.

She said healthy reefs can suffer degradation due to cyclones; boat crashes (especially large boats like tankers or shipping vessels); destructive fishing (anchor damage or dynamite fishing); poorly managed tourism; and mass coral death (coral bleaching) followed by storm waves.

“Coral rubble is a natural part of coral reefs and an important habitat being home for many sea creatures,” Ms Dodgen said.

“However, too much loose rubble can be a problem as it can kill baby corals that are trying to return to these areas by burying them, or by scraping them when the rubble the baby corals are attached to tumbles in currents and waves. This can prevent reefs from re-growing after they have been damaged.

“Therefore, rubble stabilisation is increasingly being used to help restore degraded reefs.

“What I’m doing is actually an ecology experiment. I will create some distinct areas where we will stabilise the rubble by using a mesh – a method that it already being used to restore reefs. Then we will observe those areas over time to see what is growing there and whether this stabilisation has a significant impact on the community that lives in and on the rubble,” Ms Dodgen said.

“Once we’ve set up these areas for observation, we’ll head back to Cairns every four months over the course of a year and record any changes.”

“As researchers, we often study the obvious elements in an ecosystem. For example, in land-based studies, we focus on and prioritise understanding the trees in forest restoration.

“However, it has become increasingly clear that the ecological community in the soil plays a vital role. Similarly, in the realm of coral reef research, we have dedicated considerable efforts to studying coral, but the organisms naturally growing in the rubble are just as significant because they help contribute to building the solid reef on which all corals grow on,” Ms Dodgen said.

“My project is driven by the realisation that a comprehensive understanding of the natural recovery processes of coral reefs requires us to delve into the intricate dynamics of these often-overlooked environments and organisms.

“By shedding light on the organisms that live and bind rubble to build a solid reef, this will help us uncover the factors that enable or hinder the natural recovery of these areas on coral reefs.

“Ultimately, this research will contribute to the growing body of knowledge dedicated to the preservation and restoration of our precious coral reef ecosystems.”

Tanya Dodgen’s PhD is part of the Reef Restoration and Adaptation Program (RRAP). RRAP’s mission is to develop and test novel scientific solutions and make those available to managers to help the Great Barrier Reef and other coral reefs survive in the decades ahead, as global warming is gradually arrested.

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