Scientists have discovered “tree rings” in coral-reef building algae that could show signs of impacts of climate change.

The Griffith University team made the find using state-of-the-art techniques in laboratories at the Griffith University Nathan campus, the Australian National University and the Australian Institute of Marine Science.

Similar to tree rings, skeletal banding can provide information on growth rate, age, and longevity, as well as records of past environmental conditions and the coralline algae’s growth responses to such changes.

Published in the journal PLOS One today (Thursday), the researchers show the rings for the first time in tropical reef building species from the Great Barrier Reef. The bands are created by changes in skeletal mineralogy and density, and reproductive structures.

“Variations in the spacing in between the bands may reflect a change in the environment. Understanding this could help us understand past or future climate change events and their impacts on the reef,” said lab head Associate Professor Guillermo Diaz-Pulido.

Associate Professor Diaz-Pulido said these algae were important because they provided the foundations for coral reef development.

“The coral provides the building blocks but these algae are the cement or the mortar of the reef. Without them the blocks wouldn’t hold together.”

Associate Professor Guillermo Diaz-Pulido said with the rise of ocean acidification and warming threatening the health of coral reefs, it was vital that more effective, accurate and efficient methods of obtaining coralline algae baseline information be identified. This would not only increase our knowledge of the reef, but also contribute with data and indicators critical for their management and conservation.

Dr Bonnie Lewis (Griffith), Dr Janice Lough (AIMS) and Dr Merinda Nash (ANU) co-authored the paper.

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