Future health of coral reefs written in the sand

October 13, 2022

University of Sydney geoscientists deploying instruments into sand aprons at One Tree Island, Great Barrier Reef [Credit: University of Sydney]But the study also found more signs of trouble for coral reefs: carbonate productivity today is half what has been for thousands of years of sand apron formation in the southern Great Barrier Reef. Hence, predicting the health of any single coral reef group, and how they will behave in response to climate change, is an intricate puzzle. The team later worked with satellite imagery to measure the sand aprons and estimate their volume for each reef. “If we can understand the evolution of sand aprons in each reef over time, we can use the data to manage coral reefs and prepare for climate change.”As coral reefs around the world respond to warming oceans, it will change how corals behave. “Our current research involves modelling what this will mean for the future of the Great Barrier Reef, and these data are going to be essential for that,” she added.

University of Sydney geoscientists deploying instruments into sand aprons at One Tree Island, Great Barrier Reef [Credit: University of Sydney]

But the study also found more signs of trouble for coral reefs: carbonate productivity today is half what has been for thousands of years of sand apron formation in the southern Great Barrier Reef. “Our results suggest that ecosystem health was much better then, so we’re likely seeing the effects of climate change in our present-day data,” added Associate Professor Vila-Concejo, Co-Director of the University’s Marine Studies Institute.

How corals grow and recede, and under what conditions, and how healthy they are, is dependent on an incredibly complex combination of factors – such as waves and storm surges, sedimentation rates, seawater chemistry, land-based runoff and even fish populations. Hence, predicting the health of any single coral reef group, and how they will behave in response to climate change, is an intricate puzzle.

However, the researchers found that sand aprons – formed as waves and currents from reef crests carry sediment that becomes trapped in the reef lagoons – can be used to estimate carbonate productivity over time, and therefore the health of a coral ecosystem.

The field team, coordinated by Dr Sarah Hamylton, an Associate Professor at the University of Wollongong and an Honorary Associate at the University of Sydney, worked from a 12-metre catamaran to visit 21 reefs in the southern Great Barrier Reef, collecting over 100,000 records of reef bathymetry and composition.

The team later worked with satellite imagery to measure the sand aprons and estimate their volume for each reef. They then matched that data with carbonate production measurements taken over more than a decade to try and understand sand apron evolution, and how it correlated with productivity.

“The formation of sand aprons by lagoon infilling is a function of reef size, and a self-limiting process controlled by the surrounding hydrodynamics and in response to the ebb and flow of sea-level changes,” said Associate Professor Vila-Concejo, who is also Deputy Director of the One Tree Island Research Station, located in the Great Barrier Reef. “If we can understand the evolution of sand aprons in each reef over time, we can use the data to manage coral reefs and prepare for climate change.”

As coral reefs around the world respond to warming oceans, it will change how corals behave. The climate effects on the drivers for sand apron development – sediment production, hydrodynamic forcing, and the infilling of lagoons – are not yet clear. But the study indicates that understanding their behaviour and evolution provides a powerful shortcut to determining overall reef health.

In addition, by combining modern analysis of sand apron accretion with data going back 8,000 years, the researchers can establish the background rate of coral productivity.

“Our findings show that the carbonate production was much higher during the Holocene – the last 11,700 years of Earth's history – but that the average rate of production today is down 50 percent on this. That is a cause for concern,” Associate Professor Vila-Concejo said.

“Our current research involves modelling what this will mean for the future of the Great Barrier Reef, and these data are going to be essential for that,” she added.

 

The source of this news is from University of Sydney

Popular in Research

1

Mar 19, 2024

Nancy Hopkins awarded the National Academy of Sciences Public Welfare Medal

2

Mar 14, 2024

MIT Faculty Founder Initiative announces finalists for second competition

3

Mar 12, 2024

Corinne Bailey Rae is the 2024 Spring Artist-in-Residence at NYU’s Clive Davis Institute of Recorded Music

4

Mar 11, 2024

MSCA Postdoctoral Fellowship 2024: Call for expression of interest

5

Mar 9, 2024

Use of cultural specific terms in times of crises can cause greater health inequalities

White House fights back against age comments in Biden probe

1 day ago

Sean ‘Diddy’ Combs blasts feds’ ‘military-level force’ during raid of his homes, calls investigation a ‘witch hunt’

1 day ago

Boeing CEO Dave Calhoun to step down; board chair and commercial airplane head replaced in wake of 737 Max crisis

2 days ago

Biden, Promising Corporate Tax Increases, Has Cut Taxes Overall

2 days ago

Remembering MIT Copytech Director Casey Harrington

1 day ago

Noubar Afeyan PhD ’87 to deliver MIT’s 2024 Commencement address

3 days ago