9 November 2015
At a study site in the Solomon Islands, a large earthquake in 2007 caused the land to sink relative to the sea surface – which provided the opportunity to see how the reef adjusted to relative sea-level rise. Photo: M. Saunders
At a study site in the Solomon Islands, a large earthquake in 2007 caused the land to sink relative to the sea surface – which provided the opportunity to see how the reef adjusted to relative sea-level rise. Photo: M. Saunders

UQ marine scientists have plotted the effects of a recent earthquake to model how coral reefs might behave under a rapid rise in global sea-levels.

Coral reefs play a critical role in the life cycle of countless marine species, and reef fish are a primary food source for millions of people.

With the number of people living on tropical coasts expected to reach more than 1.9 billion by 2050, it was vital to understand the effect a significant rise in sea-level is likely to have on reef ecology, UQ Global Change Institute research fellow Dr Megan Saunders said.

“At our study site in the Solomon Islands, a large earthquake in 2007 caused the land to sink relative to the sea surface –which provided the opportunity to see how the reef adjusted to relative sea-level rise,” she said .

“Over six years the corals grew rapidly in response to the deeper water, which suggests that some corals may be able to keep up with the expected sea-level rise in the future. 

“However, particular species of coral had to be present for the reef to respond rapidly, which indicates that species extinctions may reduce the capacity of reefs to respond to sea-level rise. 

“Further, species diversity decreased in areas of the reef that responded to the changing conditions, suggesting a reorganisation of the reef community in response to sea-level rise.”

Many Indo-Pacific coral reef flats currently support relatively few corals because they are limited by exposure at low-tide.

Although the sea-level rise attributed to the 2007 earthquake happened over a time-scale of only minutes, the study’s findings demonstrated that healthy coral reefs could potentially respond rapidly to a worst-case scenario of extremely rapid rise in sea-levels, Dr Saunders said. 

“Unfortunately reefs around the world are threatened by a myriad of human activities, which will likely reduce their capacity to adjust to sea-level rise.

“An important next step for this research will be to look at how warming temperatures, ocean acidification, and local stressors such as sedimentation and overfishing affect reef response to sea-level rise,” she said. 

The study was published in the journal Coral Reefs.

Media: Dr Megan Saunders: m.saunders1@uq.edu.au, GCI Communications +61 7 0438 285 283

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