Seagrass: blue carbon gold mine
The CO2 stored in the seagrass meadows could be worth $5.2 billion.
Image: Rich Carey/Shutterstock

Australia could be sitting on a goldmine of carbon dioxide stored in seagrass meadows worth more than $5.2 billion according to ECU research published in the journal PLOS ONE.

Using conservative estimates, ECU’s Centre for Marine Ecosystems Research found there could be more than 150 million tonnes of carbon stored in more than 92,500 sqkm of seagrass ecosystems fringing Australia’s coastline.

Based on a carbon trading price of $35 per tonne in 2020, as predicted by the Federal Government, Australia’s Blue Carbon reserves could be worth billions of dollars on the international carbon market.

Centre for Marine Ecosystems Research Director and lead researcher of the project, Professor Paul Lavery, said the research showed it was vital Australia’s fragile seagrass meadows are preserved.

“It’s essentially a win, win, win scenario. A win for the economy, a win for conservation and a win for society through the services the ecosystem provides,” he said.

But Professor Lavery said it wasn’t as simple as going out and planting new meadows of the notoriously hard to propagate seagrass.

“What is imperative at the moment is to preserve what we have,” he said.

Seagrass meadows are currently under threat from nutrient pollution, dredging and other coastal development.

Blue carbon is a term used to describe carbon dioxide sequestered in coastal plant ecosystems including seagrass, mangroves, coral reefs and salt marshes.

The study is one of the first to examine the blue carbon storage capacity of Australia’s seagrass meadows following similar research in the Mediterranean.

ECU’s project analysed the top 24cm of sediment at 17 different locations around Australia encompassing 10 different seagrass species and a variety of ecosystems.

The research found seagrass meadows were accumulating carbon at a rate more than three times faster than a typical tropical rainforest, which are often touted as the lungs of the world. However other estimates have the rate at as much as 10 times faster.

The research estimated Australian seagrass meadows are absorbing around 1 million tonnes of carbon each year, equivalent to $35 million in carbon credits using the 2020 carbon price estimate.

Professor Lavery said while the rate at which seagrass meadows are absorbing carbon sounds high, 1 million tonnes per year accounts for only around 0.6 per cent of Australia’s annual emissions.

However, he said the rate could be much higher and more research is needed to quantify the true potential of Australia’s seagrass.

The next step, according to Professor Lavery, is to develop an efficient way to find out how much carbon is being absorbed and how much is stored and move the resource into a carbon trading market.

This question is the subject of ongoing research in Australia and Europe which Professor Lavery is involved with.

To access the full version of the article in PLOS ONE click here.

Editor's note: Original news release can be found here.