Critical sea grass is under threat, James Cook Uni study finds

Over half of the world’s most important sea grass meadows are threatened by rising temperatures, according to a new study at James Cook University.

Sea grass is critical to marine life. Picture: Brendan Radke.

Over half of the world’s most important sea grass meadows are under threat from increasing temperatures, according to a new study at James Cook University.

A project examining the 28 World Heritage listed sea grass habitats found that more than 50 per cent “are highly vulnerable to climate change impacts, with long-term increases in sea-surface temperature and short-term marine heatwaves being the greatest threats,” said JCU masters graduate Riccardo Losciale.

He said that sea grasses – which have multiple benefits including absorbing carbon dioxide, protecting coastlines by stabilising sediment and dampening waves, and acting as a breeding ground for many fish and crustacean species – were already in decline.

“On a global scale, the documented area of seagrass has declined by 19 per cent since the start of the second industrial revolution around 1870, due to the cumulative impacts of human-caused and climate stressors,” Mr Losciale said.

JCU scientist Scott Heron, who supervised the project, said most seagrasses are suffering from the impact of climate stressors and poor water quality driven by human activities.

He said the project had found that most managers of sea grass habitats were not well equipped to deal with these risks and recommended changes. It suggested more involvement of sea grass experts, systematic mapping and monitoring, raising community awareness and encouraging citizen scientists to get involved. Baselines needed to be established to measure changes in the sea grass environments over time.

“It’s critically important that we rapidly decrease greenhouse gas emissions – the principal cause of climate change – whilst limiting human activities that can lead to negative cumulative impacts,” Professor Heron said.