Land-based seaweed trial a nationwide first


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, Agriculture Minister Damien O’Connor said.

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). 

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 bioremediation 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 will grow the algae for 12 months, which will provide data from real-world ambient conditions,” Damien O’Connor said.

“Ulva will be cultivated and scaled up at the University of Waikato’s aquaculture facility. 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. Thames-Coromandel District Council is gifting the land lease for the project term worth $40,000, with support from Ngāti Maru and Ngāti Hako. 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.