Why feeding cows on a little daily seaweed could save the earth


The clumps of red seaweed bubbling under the surface in glass flasks in a West Cork laboratory may not look like they could save the planet, but they could play a key role in cutting greenhouse gas emissions.

Marine biologist Dr Julie Maguire has been carrying out experiments in her oceanside laboratory at the Bantry Marine Research Station to show how a certain strand of Irish seaweed - Asparagopsis armata - could cut methane emissions in cows by between 40pc and 98pc.

Most cows chew the cud, but it has been discovered that chewing on seaweed could stop the bovines - and other ruminants, such as sheep and goats - from burping out methane into the atmosphere. As livestock are a major contributor to greenhouse gases in the world, the addition of around a spoonful of seaweed to their diet a day could have a dramatic effect on reducing emissions. This is urgently required in light of the recent Intergovernmental Panel on Climate Change’s grave report.

The seaweed link was originally discovered in a tropical Australian seaweed, but the Irish plant has been found to have similar properties.

Over summer, the Limerick scientist has been testing the cultivation of the gas-dispelling Irish seaweed on long rope lines under surface at the picturesque Toormore Bay on the Mizen peninsula, to ensure it can be produced to feed Irish herds of cattle.

“We have done so much to reduce emissions from cars, but this would be a really simple solution because you don’t need that much of it. It’s literally a sprinkle a day,” said the scientist after returning from checking her growing seaweed lines in the sea off Crookhaven.

“A tiny amount is enough to reduce the emissions up to 98pc, which is a great reduction. I’d love to see it happen. I grew up on a dairy farm. My sister is married to a farmer. The farmers are just crying out for a solution.” She said if animals were fed “some seaweed that is completely natural and is growing away wild in the ocean, it would be better all around.”

The research station began testing strains of Irish seaweed in the laboratory after an Australian study in recent years found a tropical species of seaweed helped to reduce methane emissions in cows.

“An Australia study started it off and they found that an Australian tropical species worked wonders, and they did all these animal trials,” said Dr Maguire.

“We had an asparagopsis over here and we wondered if it did the same thing. So we tested it and loads of other species for the active ingredient. They have this compound that is common in all seaweeds called bromoform, but in asparagopsis it has 400 times more than the next highest seaweed. That is huge.

“It has the ability to change the bacteria in the cow’s stomach; this bacteria would normally produce methane, but when you change its composition it produces something else which is innocuous enough.”

As methane is said to be up to 86 times more potent than carbon dioxide (CO₂) when it comes to global warming, a reduction in the emission rate would have a major effect on climate change.

Dr Maguire said they are currently working on growing the seaweed - which was first identified by scientist Maureen de Valera in 1942 - to use in animal trials.

“First of all we have to grow it and get enough biomass. We have been harvesting and storing the stocks for an animal trial which we’re hoping to do. We’ve been asked by a couple of different organisations for material for an animal trial,” she said.

“We’re interested in learning to grow the seaweed and seeing how that works and even growing it in such a way to make more bromoform, to tune it to make more, and then hand it over to the animal people.

“There are two ways to grow it - there is a free-living stage where it looks like a bit like a pom-pom like you would have on top of a hat. We’ve been figuring out the best way to grow it under different lights, different temperatures, and different nutrients. It’s pretty easy to grow.

“We’re trying to plant it on to long-lines. It grows, you can cut it and it will grow back like grass. It’s a nearshore plant; you find it anywhere around the coast in shallow water.

“Plants that come from the sea are really ancient - they are amazing. They are very good at fighting disease, even the sun because they have their own natural sunblock. They’ve evolved over time and come with all these bio-actives we can use as people. The biggest issue is supply. You have to convince other people to grow it, which I think would be easy enough. Seaweed farmers are new to the industry; if there is a market for seaweed the seaweed farmers will grow it.”

She is hoping an animal trial will begin by next year. “The animal trials have been done in other countries but they haven’t been done here,” she said.

“We will either engage with an animal feed company who will add it to animal feed like nuts or we could teach the farmers to grow it themselves in tanks. You need some seawater, some light, some nutrients, and there you go, especially if you live by the coast. You have to convince people because there are people who doubt the science.”

And she said the added benefit to growing seaweed is that it absorbs CO₂ from the atmosphere.

“The double whammy with seaweed which can’t be forgotten is seaweed is one of the best carbon sinks on the planet. It soaks up so much CO₂ to grow. It has a double function on the greenhouse gas emissions.”

Source – The Irish Independent