June 24, 2014

Ocean impacts from climate change broader than initially predicted

Study to map the Great Barrier Reef reveals impacts from sea-level rise could be broader than first thought. 

Climate change in marine environments could be more difficult to predict than first thought, with researchers measuring how interactions between ocean ecosystems are affected by environmental change for the first time.

Research just published in Nature Climate Change, which involved UOW researchers Professor Colin Woodroffe and Dr Sarah Hamylton from the School of Earth and Environmental Sciences, has found sea-level rise could negatively affect tropical marine ecosystems by mid-century.

Lead author and researcher from the University of Queensland, Dr Megan Saunders, said the response of one ecosystem to climate change, such as coral reefs, could have significant impacts on neighbouring ecosystems.  

“As sea levels rise we can expect to see deeper waters over coral reefs, leading to larger waves, more erosion and shoreline damage, and ultimately harsher conditions for seagrass and other ocean communities that rely on wave protection provided by reefs,” Dr Saunders said.

“In addition to storing carbon, seagrass acts as a form of shelter for fish, produces high levels of oxygen and offers wave protection, so its destruction could have devastating consequences.”

The hundreds of millions of people who live near tropical coasts globally will be the first affected by sea level rise.

Co-author Professor Colin Woodroffe from UOW said many people would eventually have their food sources and income streams destroyed, in addition to the immediate threats of sea level rise including inundation and inland migration.

“We know that climate change, particularly sea-level rise, will have serious consequences for people living on coral islands.”

“This research indicates that it will be more complex to forecast the impacts on islands, because not only will it depend on how the reef responds, but the nature of that response will have effects on other interdependent coastal ecosystems,” Professor Woodroffe said.

"Coastal habitats will be permanently lost and others altered irreparably as they attempt to acclimatise to the changing conditions,” Professor Hoegh-Guldberg from the University of Queensland added.

The research, undertaken at Lizard Island, Great Barrier Reef, Australia, involved ecologists, modellers, geographers and engineers from UOW and the University of Queensland to map the presence of coral reefs, measure seafloor topography, and monitor the distribution of seagrass and coral in a set area.

The team then studied wind data to determine likely changes in wave conditions from rising sea and modelled how the ecosystems may respond to sea level rise.  

“Unfortunately we are committed to a certain level of climate change and there will be sea-level rise in future years, but strong action to reduce greenhouse gas emissions and other impacts on ocean ecosystems such as overfishing could help reduce the damage,” Dr Saunders said. 

Media contact: Elise Pitt, Media & PR Officer, +61 2 4221 3079, +61 422 959 953 or epitt@uow.edu.au.