Blue Carbon investment boosts coastal wetland restoration projects with multiple benefits

The state’s growing investment in blue carbon is using coastal wetlands to capture and store greenhouse gases with potential economic as well as environmental benefits.

Blue carbon is shaping up as one of South Australia’s new growth industries and has proven to be more efficient in capturing greenhouse gases than current land-based methods, according to experts.

Environment and Water Minister David Speirs said on Friday the storage of carbon by marine and coastal ecosystems was also crucial in tackling climate change.

“Blue carbon is brimming with potential … SA is poised to grab hold of the opportunities it presents,” he said.

“Developing blue-carbon projects presents us with multiple benefits, from significant sequestration opportunities, to strengthened resilience of our precious coastline, to habitat restoration for nationally threatened species as well as new economic opportunities.”

Four research projects will strengthen the evidence base, while a $1.2m partnership with The Nature Conservancy and the COmON Foundation will restore up to 2000ha of wetlands across Gulf St Vincent and Spencer Gulf.

Associate Professor Jason Tanner from SARDI with sandbags and seagrass at West Beach. Picture: Naomi Jellicoe

This will be one of the first coastal wetland restoration projects funded under the Commonwealth Emissions Reduct­ion Fund’s new blue-carbon methodology.

It will also help to establish a blue-carbon credit scheme, which will provide an extra financial incentive for revegetation. Oceans program director for The Nature Conservancy Dr Chris Gillies said he had high hopes for sustainable financing of wetland protection.

“SA is a leader in this area,” Dr Gillies said.

“If successful, this model could be applied globally and contribute significantly to reducing emissions worldwide.”

COmON Foundation chief executive officer John Loudon said coastal wetlands – consisting of mangroves, seagrasses and salt marshes – “absorb and store carbon at concentrations up to four times greater than terrestrial forests and provide countless benefits for biodiversity and local livelihoods”.

“They protect coastal communities from flooding and are nursery areas which support commercial fisheries,” he said.

“We are particularly excited to see the potential to restore mangrove wetlands in South Australia’s unique and biodiverse gulf estuary systems.”

Previous research has found SA has more than one million hectares of seagrass, close to 20,000ha of tidal saltmarsh and 16,420ha of mangroves. That adds up to 1.12 million hectares of blue-carbon ecosystems.

Dr Alice Jones, of the University of Adelaide, is analysing soil cores to improve carbon maps for the Green Adelaide area. Flinders University marine biology professor Sabine Dittmann found reintroducing tidal flows to one pond in the Dry Creek salt field worked well and will now put a dollar value on tidal flows.

“The seaward sections of the salt field north of St Kilda, which are mostly on Crown land, are especially suitable for introducing tidal flow, which could provide substantial carbon offset opportunities,” Prof Dittmann said.

revious research has found SA has more than one million hectares of seagrass, close to 20,000ha of tidal saltmarsh and 16,420ha of mangroves. That adds up to 1.12 million hectares of blue-carbon ecosystems. Picture: Naomi Jellicoe

New bags of tricks for our seagrass forest

Thousands of sandbags are being submerged off the coast between Glenelg and Semaphore in the nation’s largest-ever project to restore disappearing seagrass.

Seagrass is a vital component in healthy marine environments, reducing erosion, storing blue carbon and forming habitats for marine animals.

But much of our seagrass has been lost to historical practices associated with stormwater run-off, industrial effluent and wastewater treatment.

South Australian Research and Development Institute’s principal scientist for environmental assessment and rehabilitation, Associate Professor Jason Tanner, said the organisation was making about 50 boat trips in the area to drop sandbags on to the sea floor.

Each trip would leave about 1000 bags in the area, to which young seagrasses would attach.

“The sandbags provide a stable substrate and the hessian rots away – it’s biodegradable. And by then the seedlings are big enough that they can survive on their own,” Prof Tanner said.

The $1m project will re-establish about 10ha of seagrass.

Environment Minister David Speirs said seagrass meadows were an important buffer for the ocean’s wave and current energy to prevent erosion, also supporting biodiversity and good water quality.

“Over the last half-century, around one-third of seagrass along the Adelaide coast has been lost and while we have seen some natural regeneration, it’s imperative that we work to restore these seagrasses as they’re really important to the marine environment,” he said. “Per hectare, seagrasses can store up to twice as much carbon as terrestrial forests.”