More warm, acidic oceans will require greater reef care

WASHINGTON - A new study has said that the more our oceans become warmer and acidic, the harder we will have to work to save our coral reefs.

Dr Ken Anthony of the ARC Centre of Excellence for Coral Reef Studies and The University of Queensland’s Global Change Institute has found that reefs already overfished and affected by land runoff are likely to be more vulnerable to increasing CO2 in the atmosphere caused by the burning of fossil fuels.

“As CO2 levels climb to 450-500 parts per million - as they are now expected to do by 2050 - how well we manage local impacts on reefs like fishing and runoff will become absolutely critical as to whether they survive as coral reefs, or are overtaken by algae that compete with corals for space on reefs,” Anthony said.

While warmer waters cause bleaching, CO2 dissolving out of the atmosphere weakens the corals by interfering with their ability to form their skeletons, making them more vulnerable to impact by storms.

The team’s study has far-reaching implications for the preservation even of well-managed reefs as well as reefs in developing countries, where most reefs are located and where reefs face high levels of stress from human activities.

“Put simply, our model indicates that the more CO2 we humans liberate, the harder it will become for coral reefs, as we know them, to survive. This means they will need all the help they can get in the way of good management to prevent their being overgrown by sea weeds,” he said.

“Coral reefs in developing nations, where most of the world’s reefs occur and overfishing and nutrification remain key concerns, are particularly vulnerable, highlighting the need to continue to build capacity amongst reef managers and governments in areas like SE Asia,” the authors say.

“A failure to rapidly stabilize and reduce the concentration of CO2 in the Earth’s atmosphere is likely to lead to significant loss of key (coral) framework builders such as Acropora, irrespective of the effectiveness of local management,” the scientists conclude.

“However local reef management efforts to maintain high grazing fish populations and prevent runoff of silt, fertilisers and sewage from the land will play a critical role in maintaining coral resilience while CO2 concentrations are stabilized,” they added.

Their paper was recently published in the journal Global Change Biology. (ANI)