The world鈥檚 seagrass meadows are in trouble 鈥� but Australian scientists say early action can save them, even as sea levels rise.
University of Queensland Global Change Institute researcher Dr Megan Saunders collaborated with the on new research reported in the journal .
鈥淲e鈥檙e currently losing around seven per cent of global seagrass area every year due to a combination of human impacts,鈥� Dr Saunders said.
鈥淭hose losses are likely to accelerate as sea levels rise.鈥�
As waters deepen due to sea level rise and become murkier due to human activities on land, seagrass meadows in deeper waters are deprived of the light they need to stay alive.
Dr Saunders said seagrass areas were a vital factor in the battle against climate change.
鈥淲e need to take action needs to stabilise or even expand the area of seagrass beds globally,鈥� she said.
鈥淭hey can lock up an awful lot of carbon and help slow climate change 鈥� as well as restoring degraded fisheries.鈥�
Dr Saunders said the keys to saving and regenerating the world鈥檚 seagrass beds were:
鈥� Revegetating bare farmland to control erosion and runoff in river catchments
鈥� Better managing river banks
鈥� Better managing nutrient and soil runoff from cities
鈥� Local authorities adopting more flexible coastal planning for development, to allow future seagrass meadows to expand into new areas as sea levels rise.
Dr Saunders said the success of the plan depended on creating light conditions at the 鈥渄eep edge鈥� of seagrass meadows which allow seagrass species to continue to flourish.
鈥淭his is the sort of information our coastal planners will need as we seek to cope with the changes imposed by sea level rise and other impacts of climate change,鈥� she said.
鈥淚t also means we can think further ahead about what is needed to keep these essential ecosystems alive and thriving by allowing them to move to occupy new niches as they emerge.鈥�
Dr Saunders and her research colleagues used Australia's Moreton Bay as a laboratory to investigate the fate of seagrass meadows generally, in the context of an expected 1.1 metre sea level rise this century.
Moreton Bay is listed as a 鈥淩amsar Wetland鈥�: these are areas of international importance that are listed under the Convention on Wetlands, also known as the .
Dr Saunders said the Moreton Bay research indicated a 鈥渃oastal retreat鈥� strategy could reduce the loss of seagrass cover due to sea level rise by 2100 from 17 per cent to 5 per cent.
鈥淐ompared to coral reefs, seagrasses are the ugly duckling of marine ecosystems,鈥� she said.
鈥淭hey are major nurseries for fish and prawns, and so support our food supply.
鈥淭hey trap huge amounts of carbon 鈥� and could sequester even more if we looked after them.
鈥淭hey cleanse the oceans by trapping sediment and nutrients.鈥�
The team鈥檚 research indicates that a 1.1 metre rise in sea level would result in a 17 per cent decline in seagrass cover in Moreton Bay due to the loss of light alone.
Equivalent losses could occur globally, although exact numbers would depend on the location.
Seagrasses trap an estimated 48-112 million tonnes of carbon every year.
Their loss means this carbon will be re-released into the atmosphere, accelerating global warming.
The research was a collaboration between the Australian Research Council-funded Australia Sea Level Rise Partnership, based at 宅男导航鈥檚 Global Change Institute, and the ARC Centre of Excellence for Environmental Decisions (CEED). CEED鈥檚 research tackles key gaps in environmental decision making, monitoring and adaptive management.
Details on the team鈥檚 research appear in the CEED publication , and the full paper, by Saunders MI, Leon J, Phinn SR, Callaghan DP, O鈥橞rien KR, Roelfsema, CM, Lovelock CE, Lyons MB, Mumby PJ (2013) appears in Global Change Biology.
Contact: Dr Megan Saunders, CEED, ASLRP and 宅男导航, +61 (0)7 3443 3116 or +61 (0)432 034 814. Karen Gillow, communication manager CEED, +61 (0) 402 674 409. Carolyn Varley, 宅男导航 media, +61 (0)7 3365 1120 c.varley@uq.edu.au.
