Blue Carbon: what is it and why do we care?

What are Blue Carbon ecosystems?

Blue Carbon ecosystems are coastal ecosystems, such as mangrove forests, seagrass meadows or intertidal saltmarshes, that capture and store atmospheric carbon. All three ecosystem types can be found within Port Phillip Bay, right in our backyard! In fact, not far from Port Phillip Bay you can find the southernmost mangroves in the world located at Millers Landing on the northern section of Wilsons Promontory National Park.

Why should we care about Blue Carbon ecosystems?

Here are just ten of the incredible number of ways Blue Carbon ecosystems provide benefit to humans…

1. Carbon storage
   Blue Carbon ecosystems are considered one of the Earth’s most efficient carbon sinks, burying carbon faster than tropical rainforests and locking away carbon in the ground for millennia to come. These ecosystems are vital in the battle against climate change as they help draw down atmospheric carbon dioxide.
   

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2. Water filtration
   As water flows through Blue Carbon ecosystems, a web of roots and soil filters out pollutants (herbicides, pesticides, heavy metals and fertilisers). Excess nutrient run-off can then be used by saltmarsh, mangroves and seagrass to fuel growth.
   

   Image: Isaac Spedding/Shutterstock.com

    

3. Coastal protection from storms
   Blue Carbon ecosystems are capable of absorbing the wind and wave energy produced by storms, helping to lessen the impact. A study found that having a belt of mangrove forests 500 metres wide can reduce wave height between 50 to 100%. When storm flooding occurs, saltmarshes often act like huge sponges, soaking up excess water.
   

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4. Coastal protection from sea-level rise
   Blue Carbon ecosystems have the ability to regulate the elevation of their habitat in order to adjust to rising sea-level. They do this by trapping incoming sediment.
   

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5. Preventing coastal erosion
   The complex matrix of roots mangroves, seagrass, and saltmarsh work to trap and stabilise sediments to help limit erosion. These ecosystems help prevent erosion so well that engineers are beginning to incorporate these natural infrastructures into their constructed coastal defence designs. Keep an eye out as you walk along the shoreline of Port Phillip Bay!
   

   Image: Matthew J Thomas/Shutterstock.com

    

6. Bird habitat
   Many species of shorebirds and migratory birds, including some endangered species, call saltmarsh and mangrove ecosystems home. They use these habitats as important feeding, breeding, roosting or overwintering grounds, some flying from over 10 000 km away. The critically endangered Orange-bellied Parrot spends winter feeding in coastal saltmarsh in Victoria and Southern Australia.
   

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7. Supporting people’s livelihood
   Healthy coastal Blue Carbon ecosystems are critical for the livelihoods and wellbeing of coastal communities. These ecosystems provide resources and services including shelter, food, water, and income from harvested resources like fish, invertebrates and wood.
   

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8. Fish habitat
   It is estimated that two-thirds of all the fish consumed worldwide are dependent on Blue Carbon ecosystems. Many commercially important and endangered fish use these ecosystems for breeding grounds and shelter.
   

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9. Important tourism and recreational areas
   These ecosystems provide suitable environments for a variety of activities, including birdwatching, swimming, snorkelling, and fishing, attracting hundreds of thousands of tourists each year. Port Phillip Bay has many Blue Carbon ecosystems that you can get out and explore. Some great spots include Swan Bay, Limeburners Lagoon State Nature Reserve, Jawbone Marine Sanctuary, Point Cook Coastal Park, and Cheetham Wetlands.
   

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10. Cultural Importance
    Land and sea country is central to Indigenous livelihood and wellbeing. Blue Carbon ecosystems are significant to Traditional Owners as ceremonial and initiation sites and traditional hunting and gathering grounds. Traditional Owners have utilised most plants and animals in these ecosystems for food, fibre, containers, tools, weapons, transport, shelter and medicine, with many species representing significant totems.

Ecosystems under threat

Blue Carbon ecosystems are in rapid decline globally, with the main causes largely driven by human activities. Common drivers are aquaculture, agriculture, mangrove forest exploitation, pollution from both land and sea, and industrial and urban coastal development. All of these factors are further exacerbated by climate change. When these Blue Carbon ecosystems are degraded, disturbed or converted, they shift from being major carbon sinks to becoming significant carbon-emitters leading to even more negative climate effects.

The Victorian Coastal Wetland Restoration Program

Thankfully, change is beginning to happen through the development and implementation of numerous marine and coastal policies, management strategies, and on-ground restoration work to protect and restore these ecosystems’ Blue Carbon value.

A team of scientists from the Blue Carbon Lab (BCL) at Deakin University is working to restore several Blue Carbon ecosystems with low-cost methods along Victoria’s coastline, including two sites within Port Phillip Bay (Avalon Coastal Reserve and Point Lillias). The Victorian Coastal Wetland Restoration Program, funded by the Victorian Government, is completing on-ground works to improve coastal saltmarsh, to enhance biodiversity and carbon accumulation.

BCL scientists have partnered with the University of New South Wales Water Research Lab, Parks Victoria, and The Nature Conservancy to develop and test a wetland restoration and conservation strategy that will provide critical information on the ‘where’ and ‘how’ components of coastal wetland restoration for Avalon Coastal Reserve, a former saltworks currently managed by Parks Victoria. To do this, the team will model the current hydrologic regime (the patterns of how the water changes over phases and seasons) and will present various restoration scenarios that reduce the need for pumping water and improve natural connectivity and drainage through the old salt ponds in order to maximise habitat for bird biodiversity and saltmarsh (Blue Carbon).

At nearby Point Lillias, BCL is working with Waddawurrung, Wathaurung Aboriginal Corporation, Coastcare Victoria, Heritage Insight and Parks Victoria to perform remedial work on 16 sites of important cultural heritage that will protect and rehabilitate these sites from various threats such as erosion, pests and weeds, while simultaneously providing biodiversity and cultural benefits.

Project updates

To keep up to date on the progress of the Victorian Coastal Wetland Restoration Program, follow #VicWetlandRehab on social media. For more information, email the program manager Dr Melissa Wartman (m.wartman@deakin.edu.au).

The project is funded by the Victorian Government, with partial funding support from The Nature Conservancy and Deakin University, and a cash contribution from Dow Australia.

 

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Written by Dr Melissa Wartman, program manager of the Victorian Coastal Wetland Restoration Program.
Melissa completed her PhD at Monash in Biological Sciences. Her thesis investigated how key environmental drivers associated with climate change affect phytoplankton growth and physiology. Melissa has joined the Blue Carbon Lab at Deakin University working to restore coastal wetlands. When not knee-deep in mud you can find Melissa out hiking the many amazing trails in Victoria.

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