“We have a pressing emissions problem to solve – and methane from agriculture is a problem worldwide, not just for New Zealand’s dairy and beef industries. This solution is proven to work, which is why we’re rushing to grow seaweed at scale.”

Asparagopsis armata is a red seaweed, native to New Zealand and southern Australia. It contains a simple chemical (bromoform) that is contained inside specialised cells in the plant. When released in a ruminant gut, bromoform inhibits the problematic methane-producing enzymes of digestive bacteria.

Until now, the only way to reduce methane emissions from burping cows has been to have fewer cows. “Nothing comes close to our supplement in terms of competition or for immediate impact. The beauty of seaweed is that it’s been safely eaten by cows for hundreds of years so we can use it straight away.”

Trial results are consistent and impressive. The latest from June 2020 reported that steers fed dried seaweed daily at just 0.2 per cent showed a 98 per cent decrease in methane emissions and a 42 per cent increase in weight gain. No negative effects were found and no residues or changes were observed in organs or meat. Other studies have found the same applies to milk.

“Our first big challenge is processing. Once the seaweed is out of the water, bromoform starts to migrate out of the frond so we’re developing methodologies to minimise that loss across the entire value chain. We know that when it’s in a dried state it’s very stable.”

CH4 Global surveyed the extent of wild seaweed around Rakiura Stewart Island last winter and trialled harvesting, storage and processing techniques.

“I whakapapa to the island and have strong connections there. This has enabled us to forge good, respectful relationships with mana whenua and involve them in our plans. We’re always looking for opportunities to engage locals because it brings a better understanding of what we’re doing. We have also offered iwi, including Ngāi Tahu, the opportunity to be cornerstone investors in the business.”

The seaweed was freeze-dried by Back Country Cuisine in Invercargill, taking advantage of spare capacity. Growth, propagation and harvesting studies are underway to optimise the processing at each step. Aquaculture trials are being planned in New Zealand and Australia. One site is Big Glory Bay in Paterson Inlet/Whaka a Te Wera, Rakiura, making use of gear and knowledge repurposed from a now-closed oyster operation.

“Asparagopsis is native to that area, grows well and loves the excess nitrogen from the salmon farms. Seaweed aquaculture can improve water quality and provide habitat – it is such a low impact activity.”

“We want to set things up so people can grow Asparagopsis everywhere. The market is huge and this could be a whole new industry for our country – even as big as milk powder.”