Agriculture minister officiates at trial to clean up waterways using algae

Minister for Agriculture Damian O’Connor cut the ribbon for AgriSea at Fieldays. Photo / Alison Smith

The Fieldays innovation hub was the official launch pad on Thursday for a New Zealand first in growing algae and putting it to use on land after it has done the job of filtering nutrient-overloaded waterways.

Agriculture Minister Damian O’Connor cut the ribbon for seaweed innovation company AgriSea, which is trialling the potential for sea lettuce (ulva) to absorb unwanted nutrients.

AgriSea partnered with MPI for funding and the research is led by the University of Waikato.

Commending AgriSea’s work, O’Connor said those at the forefront of innovation need “commitment and courage” to invest capital into environmentally positive solutions.

In keeping with its title of New Zealand’s high-tech Māori company of the year, AgriSea’s ribbon-cutting ceremony was officiated by the minister at the innovation hub at Fieldays near Hamilton, with footage of the ponds at Kopu showing the trial’s progress.

“There’s nothing wrong with nutrients, we pour nutrients on the paddock to grow grass and make food, but some of them end up in the wrong place,” said the minister.

“The wrong nutrients in the wrong place is something we’re all trying to address.”

The seaweed innovation company is several months into its nationwide first trial, which is in 60 sq m of land-based ponds taking water from the Waihou River.

AgriSea chief executive Clare Bradley said it is expected that 50 tonnes of dry seaweed can be produced per annum on a one-hectare scale.

Scion scientists Stefan Hill and Marie-Joo Le Guen with AgriSea chief executive Clare Bradley, Minister of Economic and Regional Development Stuart Nash, AgriSea's Tane Bradley and MP Angie Warren Clark at a visit to AgriSea in August. Photo / Alison Smith

AgriSea chief innovation officer Tane Bradley said the trial is a blueprint for seaweed-driven removal of nitrogen and phosphorous from waterways first and foremost but had the potential for AgriSea’s soil nutrition products that are returned to the land.

“I also see this as a way to help create jobs and get people interested in seaweed and natural systems,” said Bradley.

O’Connor said the Fieldays Innovation tent is where a lot of great things start.

He said AgriSea’s algae growing trial was an exciting development for the Government to support through a partnership with MPI.

“The Government’s SFFF fund is here to support people in this tent who’ve come up with ideas, that are at the leading edge, that are lateral thinking, that people won’t fund normally, but might be the breakthrough that we’re talking about.

“Some of the algae like asparagopsis are claimed to reduce methane production in ruminants by up to 80 per cent. We’re only just starting to learn what is in the sea and the science of algae and a lot of other things.

“This is about nutrient recycling, about clean water going out, capturing the nutrients and maybe being able to put them back out on the paddock. This is exciting, it’s wonderful to be here, to be part of it.

“We’ve put some of your money as taxpayers into it and I think it’s a great investment and I look forward to the results.”

Dr Stefan Hill of Crown Research Institute Scion has partnered with AgriSea. Photo / Supplied

Estimates of nitrogen applied to land in fertiliser increased from 62,000 to 452,000 tonnes (629 per cent) between 1991 and 2019, according to Stats NZ.

The loss of nutrients not absorbed by plants enters the soil and drains into groundwater feeding to waterways, promoting algal blooms and leading to reduced oxygen levels with threats to animals such as tuna (eels), kākahi (freshwater mussels), kōura (freshwater crayfish), and īnanga (whitebait).

Among other things, the trial will determine which species of ulva is present in the Firth of Thames, its bioremediation potential and a stock of seaweed to use in an aquaculture facility once commissioned.

Seaweed samples will be collected from the Firth of Thames for genetics and upscaling at an aquaculture facility at the University of Waikato marine field station in Tauranga.

Macro-algal products are used in plant fertiliser and biostimulants to boost plant immunity, for animal and human health and for nutrition and materials.

AgriSea has been using seaweed to innovate a high-quality feed and animal supplement sold to farmers, horticulturalists and beekeepers around the country using another native species, Ecklonia radiata.

Iwi support came from Ngati Maru and Ngati Hako, while Thames-Coromandel District Council has provided land for the trial and is assisting with consenting along with Hauraki District Council and Te Waka.