Seaweed used to clean up waterways in latest Kopu marine precinct trial

Chris and Marie Magnusson, with Clare and Tane Bradley from Paeroa company Agrisea, look at seaweed-growing tanks. Photo / Supplied

A land-based seaweed trial aiming to help restore our waterways is about to kick off
with Government investment beside the Firth of Thames wetland.

Paeroa seaweed innovation company AgriSea is working with the University of
Waikato on a sea lettuce-growing trial at Kopu marine precinct in the Coromandel.

The seaweed will be used to soak up the nutrients that freshwater plants are
currently unable to absorb.

The Government is investing more than $697,000 in the project through the Ministry
for Primary Industries' Sustainable Food and Fibre Futures fund (SFF Futures).

Agriculture Minister Damien O'Connor said the trial is a nationwide first and seeks to address an important environmental issue.

"Currently the loss of nutrients not absorbed by plants enters the soil and drains into
groundwater that leads straight to our waterways. This promotes algal blooms which
reduces oxygen levels, which then threatens animals such as tuna (eels), kākahi
(freshwater mussels), kōura (freshwater crayfish), and īnanga (whitebait)," Damien
O'Connor said.

"This bio-remediation project is using Kiwi ingenuity to see if the seaweed can act as
a sponge, soaking up excess nitrogen, phosphorus and helping clean our
waterways."

Three ponds totalling 60 square metres will grow the locally present green seaweed
species Ulva.

The project is the latest with Paeroa-based company AgriSea which is leading science and innovation around the use of New Zealand seaweed.

The company, which employs some 40 staff, uses seaweed to create products for the agricultural, horticultural and apiculture industries. It has also expanded with research in the area of food and potentially medical products.

Last year the company's GM Tane Bradley revealed AgriSea had received global interest from a worldwide supplier of pharmaceuticals for its work in a SMART ideas project with Scion to explore the hidden, healing properties of seaweed cellulose.

Bradley says this project for AgriSea is driven by its environmental ethos.

Algae will be grown for 12 months, which will provide data from real-world ambient conditions.

The species of Ulva will be cultivated and scaled up at the University of Waikato's aquaculture facility where researchers will use DNA barcoding to confirm its genetic identity.

Species selection will be based on growth performance for bioremediation in
conditions mimicking the Waihou river estuarine water.

The two-year project is a collective effort, with University of Waikato environmental research fellow Marie Magnusson leading the research team. Iwi Ngāti Maru and
Ngāti Hako are also providing support.

In addition to the SFF Futures funding, AgriSea is contributing $108,000 and the Agricultural and Marketing Research and Development Trust (AGMARDT) is investing $150,000. The Thames-Coromandel District Council is gifting the land lease for the project term worth $40,000, with support from Ngāti Maru and Ngāti Hako.

The Hauraki District Council and Te Waka are also assisting with the consent process. Damien O'Connor said the aims of this proof-of-concept research support many of the goals set out in Fit for a Better World, the Government's 10-year food and fibre sector roadmap aimed at lifting productivity, sustainability and creating jobs to drive New Zealand's economic recovery from Covid-19.

"This project supports sustainability, which is also in line with the Government's Aquaculture Strategy."

Seaweeds are being increasingly recognised for their potential.

"If successful, this will be an environmentally friendly way to improve water quality, create jobs in the science sector, revitalise our waterways and improve our on-land farming systems," Damien O'Connor said.