The soils beneath seagrass meadows in Western Australia’s Shark Bay UNESCO World Heritage site are a massive source of stored carbon dioxide.

Seagrass
Research

Seagrass research key to fighting climate change

Edith Cowan University's ground-breaking marine science research will inform global climate change policy for years to come.

An international research team led by ECU investigated the huge loss of seagrass as a result of a marine heatwave in the Shark Bay UNESCO World Heritage in Western Australia.

Halfway up Australia's west coast, the bay is home to the world's largest and most diverse seagrass ecosystem.

But since the heatwave during the summer of 2010/11, up to nine million metric tons of carbon dioxide (CO2) have been released into the atmosphere as a result of seagrass loss.

That's the equivalent to the annual CO2 output of 800,000 homes or 1,600,000 cars driven for 12 months.

Western Australia is home to more than half of the world's 60 species of seagrass.
Seagrasses have thrived for more than 6,000 years in Shark Bay.
Seagrass meadows have sequestered an estimated 19 billion tonnes of CO2 worldwide.
Shark Bay has the world's largest and most diverse seagrass ecosystem.

Blue carbon ecosystems

The meadows of Shark Bay are also home to endangered green turtles and dugongs which both rely on seagrass for food.

According to co-lead author Dr Oscar Serrano, the heatwave and subsequent release of carbon dioxide was unprecedented, with more than 20 per cent of meadows lost, equivalent to 1,000km2.

Seagrass meadows like those in Shark Bay absorb and store CO2 many times faster than tropical rainforests

"Seagrasses have thrived for millennia in Shark Bay, the result of approximately 6,000 years of continuous growth," he said.

"This is significant, as seagrass meadows are known as 'blue carbon' ecosystems, because they store carbon dioxide in their soils through biosequestration.

"So when you have an event such as the losses at Shark Bay, you not only lose the seagrass as a way of removing CO2, but the sequestered gas is released back into the atmosphere during seagrass matter decomposition."

Seagrass meadows like those in Shark Bay absorb and store CO2 many times faster than tropical rainforests and this 'blue carbon' could be a key to offsetting climate change as a result of burning fossil fuels.

Earlier ECU research

Previous research from ECU has estimated there could be more than 150 million tons of CO2 sequestered in the thousands of seagrass meadows in Australian waters.

Seagrass meadows aren't just threatened by heatwaves, but have been severely affected by coastal development, pollution and dredging around the world.

"We need to develop strategies to deal with the impact of climate change and extreme weather events," Dr Serrano said.

"We have seen how quickly losses can occur, and once destroyed, the capacity of seagrass meadows to recover is limited and slow, and largely depends on the arrival of seeds or seedlings."

ECU research is helping to highlight the importance of seagrass beyond its importance to the marine ecosystem by informing policy on climate change and the protection of coastal ecosystems.

Be at the forefront.

* Response required

Other research projects