Published on 04 Mar 2021

Coastal coral reefs under threat

Studying coastal coral reefs on Australia’s Great Barrier Reef, Dr Kyle Morgan of NTU’s Asian School of the Environment finds that even modest sea-level rise will limit coral growth and reduce biodiversity.

Coral communities at Paluma Shoals, Great Barrier Reef, where the study was carried out. Credit: Kyle Morgan.

Turbid coral reefs in shallow coastal waters play key roles in the marine ecosystem: They not only act as breakwater structures to protect coastlines, but also support diverse marine organisms that seek refuge within them.

To understand how the global rise in sea levels affects these coral reefs, an international team of researchers led by NTU’s Dr Kyle Morgan analysed cores drilled from turbid coral reefs on Australia’s central Great Barrier Reef.

Combining data on the reefs’ geomorphology with ecological data from living coral communities as well as corals fossilised within the sub-surface layers, the team developed models simulating broad-scale changes to reef habitats under different scenarios of sea-level rise.

“Our models show that modest increases in relative water depth above reefs over the next century will decrease the amount of habitat available for corals to grow and reduce biodiversity,” says Dr Morgan, who is an NTU Presidential Postdoctoral Fellow and AXA Research Fellow at NTU’s Asian School of the Environment.

“More severe sea-level rise will completely submerge reef flats and move many of the coral communities below depths that provide sufficient light for growth,” he adds. This situation could be exacerbated by an increase in greenhouse gas emissions, the researchers say.

The article “Projections of coral cover and habitat change on turbid reefs under future sea-level rise” was published in Proceedings of the Royal Society B (2020), DOI: 10.1098/ rspb.2020.0541.

The article appeared first in NTU's research & innovation magazine Pushing Frontiers (issue #18February 2021).