Climate Change Solution – Asparagopsis Seaweed Reduces Methane Emissions

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climate change solution - asparagopsis taxiformis

“It’s not much to look at, but the almost-feathery pink seaweed promises a lot. Methane reductions of up to 90 percent are nothing to sneeze at,” the Newsroom article “How this seaweed could slash dairy emissions” says.

A study on the effect of Asparagopsis taxiformis on methane production shows that it can reduce methane production from beef cattle by up to 99%, virtually eliminating all emissions ( Daalder, 2020).

New Zealand’s methane emissions from ruminant livestock account for one-third of its total GHG emissions. Finding a solution that could significantly cut down methane emissions will indeed be a game-changer for New Zealand and will help it realise its climate emissions goal earlier than expected (Methane Emission, 2020).

What is Asparagopsis taxiformis and where can it be found.

The seaweed’s name is Asparagopsis taxiformis, better known as Asparagopsis. The seaweed’s has a pinking colour and a featherlike structure, a native to South Australia, Tasmania, and South Island of New Zealand. In fact, the seaweed is already farmed off the coast of the Stewart Island in New Zealand by a Kiwi company.

The article cites a study that when Asparagopsis was added at greater than 2% of the cattle’s diet, it virtually eliminates methane emissions.

How does Asparagopsis work?

Daalder, M (2020) explains that:

  • Asparagopsis contain a property called bromoform that acts as methane inhibitors.
  • It inhibits the microorganism, methanogens while not affecting other bacteria.
  • Inhibiting methanogens creates more propionates which then leads to better milk production in cows.
  • This works in all ruminant animals – cows, sheep, and goats that have special stomachs to ferment plant in order to digest it.

Seaweeds have been fed to cattle since ancient times.

Feeding seaweed to cattle is not a new idea or practise. The article says that ancient Greeks have been feeding their cows with seaweeds, allowing them to roam the coast to supplement their diets (Daalder, 2020).

In 2005, A Canadian farmer has found that when his cattle consumed seaweeds it lead to more milk production than his landlocked counterparts. Not only do they produce more milk, when he tested their methane emissions, seaweed eating cows produced 20% less methane than grass-fed ones (Daalder, 2020).

Disadvantages of using Asparagopsis cited

While cattle growers and the environment could benefit from Asparagopsis, there were disadvantages that were pointed.

Bromoform in seaweed could have a carcinogenic effect.

The carcinogenic risks from cows ingesting the bromoform from the seaweed Asparagopsis which seems to be property in the seaweed that acts as methane inhibitor springs from a single study where they used mice and dosed them with 1500 times the levels that cows would normally ingest the chemical (Daalder, 2020).

Seaweed production may lead to bromoform leakage into the atmosphere.

Dr. Andy Reisinger of the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC) thinks that seaweed production would present high-risk bromoform leakage. He said that the mitigation effect is not from seaweed per se but from the bromoform that it produces.

He added that bromoform is a simple chemical that can be produced from the laboratory and it would be simpler to administer it via a bolus, rather than go to the trouble of growing seaweeds.

In other words, Dr Reisinger is saying that injecting the animal with chemical bromoform is easier than growing seaweed which may harm the environment.

Other possible adverse effects of bromoform

Also, Reisinger raised the chances of this chemical turning up as residue into food.

Rob Kinley, an Australian CSIRO scientist rejected Dr Reisinger ideas saying that the role of bromoform destroying the ozone layer is not yet well understood. In terms of the carcinogenic properties of bromoform, Kinley says little research has been done, just one study so far.

Kinley added that the problems with bromoform impacting the ozone layer and appearing on the food as residues haven’t been quantified yet whereas the benefits of seaweeds are far-reaching.

NZ Government supports Asparagopsis

In the Beehive press release, it announces that the government is giving 100 thousand to the Cawthorn Institute to use the seaweed as a cattle feed supplement for domestic and global markets. This announcement was made when NZ Prime Minister and Agriculture Minister Damien O’Connor visited Nelson’s Cawthorn Aquaculture Park. Damien calls this project a game-changer (Methane reducing cattle, 2019).

Another New Zealand technology founded by a group of local techs and bioscience entrepreneurs has been working with Australia’s CSIRO are also racing to produce cattle supplements from the seaweed Asparagopsis. They have received $500 thousand from the Provincial Growth Fund to establish a seaweed processing plant in Southland, New Zealand where the seaweed will also be grown (NZ methane-busting seaweed, 2019).

It’s interesting to note that New Zealand’s solution to reduce its dairy emissions is just found on its waters.

Not only will the seaweed reduce emission, but another upside to it is the production of better milk when cows are fed with the seaweed. The benefits do not stop there yet.

Farming, production, and processing of Asparagopsis and making them into supplements will also help create jobs, boost the dairy industry in particular and the economy in general.

Its a win-win climate adaptation and mitigation option. The downside, if there is any, seems trivial as of writing.

Sources Citations:

Daalder, M. (2020, February 19). How this seaweed could slash dairy emissions. Newsroom. Retrieved from

Roque, B.M., Brooke, C.G., Ladau, J. et al. Effect of the macroalgae Asparagopsis taxiformis on methane production and rumen microbiome assemblage. anim microbiome 1, 3 (2019).

Methane reducing cattle feed one step closer. (2019, October 18). Beehive. Retrieved from

NZ methane-busting seaweed cattle feed nears market. (2019, November 29). RNZ. Retrieved from

BACKGROUND PHOTO: By Jean-Pascal Quod – The uploader on Wikimedia Commons received this from the author/copyright holder., CC BY-SA 3.0, Link

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