Scientists studying filtering ability of mussels for natural water quality solution
01 August 2024
Cawthron scientists are studying the water filtering ability of Greenshell mussels to find out whether they could be used to improve coastal water quality through a nature-based solution called ‘bioremediation’.
There are many causes of poor coastal water quality, including pollution, sedimentation and nutrient loading from activities that occur in both the immediate environment and wider catchment.
Cawthron marine ecologist Dr Dan Crossett said the idea behind nature-based solutions is to work with nature and natural processes to solve complex challenges.
“Cawthron’s goal for environmental restoration is to find solutions that work with nature because we find they have a range of flow on benefits for both the environment and people, and they tend to require fewer inputs and have fewer unintended consequences,” Crossett said.
“In this case, we’re attempting to use Greenshell mussels to just do what they do naturally, and clean up water in the area surrounding the Port by filtering it to remove particles, nutrients and contaminants.”
The trial at Port Nelson is part of a collaborative ‘Living Filters’ project between mussel farming company MacLab, Port Nelson, and Moananui, a Te Tauihu blue economy cluster, with funding support from the Sustainable Seas National Science Challenge.
MacLab installed nearly 29,000 of their juvenile mussels off a Port Nelson wharf in January and Cawthron scientists have been monitoring the mussels and the water quality ever since to better understand the effectiveness of this approach.
A similar bioremediation project was initiated at the Ports of Auckland, with 38 seeded mussel lines attached to public spaces on an inner-city wharf to improve water quality in the Hauraki Gulf.
The Living Filters project aims to further test the concept, and Crossett said the results should improve our understanding of the best approaches to employ when using mussels for bioremediation.
“The mussels had good retention and survival after seeding them to frames, and are growing well, which is a good initial sign that they’re suited to the environment and structure they’re attached to.”
He said that Cawthron has installed data loggers and samplers to monitor various environmental factors, including water temperature, mussel behaviour and the presence of heavy metals.
“Our hope is that the mussels will help reduce contaminants entering the environment and enhance biodiversity by providing habitat for other marine organisms, leading to healthier and more resilient marine ecosystems.”