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A study carried out by The University of Western Australia at the Indian Ocean Marine Research Centre in Watermans Bay has revealed for the first time that coralline algae is able to adjust its internal chemistry to respond to rising pH levels in the ocean.

Coralline algae are ecologically important algae, critical for the formation and maintenance of reefs.

They form a calcified skeleton through producing calcium carbonate which acts as a glue vital in binding reefs together, however rising pH levels in the ocean are threatening this process.

UWA researchers Dr Christopher Cornwall, Dr Steeve Comeau and Professor Malcolm McCulloch discovered that although coralline algae can be badly impacted by rising CO2 levels, some species shows greater tolerance than previously thought.

“Ocean acidification is a major threat to coralline algal dominated reefs in both temperate and tropical ecosystems,” Dr Cornwall said.

“This study is the first to try to understand why there is a variation in the way different types of coralline algae respond to ocean acidification and examine how coralline algae can change its internal chemistry to make it favourable for forming their calcium carbonate skeleton.”

Even though some species have a greater tolerance to ocean acidification, the researchers found all coralline algae showed some form of impact.

“Understanding some of the response mechanisms gives scientists the ability to predict how different species and reefs may be impacted by ocean acidification in the future,” Dr Cornwall said.

The researchers’ task of predicting how other coralline algal species respond to ocean acidification was made difficult because there are many more species that need to be examined, and some of these species live in very different habitats. The habitats themselves could alter the impact of ocean acidification.

“The next step is to identify how the environment in which coralline algae live changes the way they elevate pH within their internal calcifying environment, and how this influences calcification and growth,” Dr Cornwall said.

“For example, if they live in habitats where CO2 levels daily reach those comparable with what we expect to occur due to ocean acidification, this could mean they are already preconditioned to tolerate ocean acidification.”

“It will also be extremely important to know how other physiological traits influence how coralline algae elevate pH internally.”

This research paper will be published today in the Global Change Biology

Media references

Dr Christopher Cornwall (UWA Research Fellow)                         (+61 8) 6488 4464 or (+61 4)56 164 151

Jess Reid (UWA Media and PR Officer)                                                                    (+61 8) 6488 6876