Wednesday, 27 January 2016
Seagrasses along Australia’s coast have been devastated by human development but new research from Edith Cowan University has shed light on how and when that damage occurred.
The new study from ECU’s Centre for Marine Ecosystems Research will be published in the journal Global Change Biology on 27 January and reveals the loss of 80 per cent of the seagrass in one area in less than 30 years.
From the 1960s until 1980s the seagrass meadows in Oyster Harbour, near Albany, Western Australia were decimated as a result of increased nutrients and deposited sediments associated with agricultural development and land clearing.
Researchers took core samples from seagrass meadows at Oyster Harbour by sinking two metre long pipes into the seafloor before extracting the core.
The cores were taken back to the lab and analysed and provide a glimpse at more than 600 years of the meadows’ history.
Lead researcher Dr Oscar Serrano from ECU’s School of Science said the cores provide a detailed history of the seagrass meadows including the cause of the massive loss of seagrass.
“Our analysis showed huge increases in phosphorus entering the ecosystem from the 1960s onwards,” he said.
“These increases in nutrients in the marine environment cause algal blooms which soak up the oxygen and light needed by seagrass and other marine organisms to survive.
“This kills off seagrass and a host of other species including fish and crustaceans, hampering their capacity to sequester CO2 and mitigate climate change.
However this damage is not unique to Oyster Harbour.
“The loss of seagrass in Oyster Harbour reflects similar damage to marine ecosystems all around Australia’s coast,” he said.
“In Australia more than 80 per cent of the population lives along the coast and that’s placed enormous stress on our coastal marine ecosystems particularly from extensive land clearing, agriculture and coastal development.”
But Dr Serrano said it’s not all doom and gloom, he hopes the research will provide insights to properly manage further environmental change, including from climate change.
“The results from this study demonstrate the power of seagrass cores to show timelines of man made pressures on estuaries and changes in the environment’s condition,” he said.
“This information can then be used to improve the capacity of scientists and environmental managers to understand, predict, and better manage ecological change in estuarine ecosystems.”
“For example, in this case we were able to identify the level of phosphorus accumulation that was associated with large-scale damage during the 1960s, 70s and 80s.
“We will now be able to use that information as a standard to guide future management of estuaries.”
Professor Paul Lavery from ECU’s Centre of Marine Ecosystems Research co-authored the research.
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