Woollen mats are now being trialled to smother an invasive oxygen weed threatening to take over some of New Zealand's lake floors.
To explain how, Northland Regional Council Biodiversity Manager Lisa Forester chats to Jesse.
Divers and wool mats on board NRC vessel, Mangapai, heading to the egeria (oxygen weed) bed to lay the wool matting in Lake Rotokawau. Photo: NRC