Freshwater

The ability to properly manage our freshwater resources requires a solid understanding of the flora and fauna which live in and interact with them.

Aquatic systems are under threat due to the introduction of invasive exotic species such as water weeds. Modelling work by NIWA has provided new information on which water bodies may be at greatest risk.

NIWA has developed a rapid, desktop model which assesses the potential impact of introducing new fish species to New Zealand. The model is customised to New Zealand's unique environment and endemic fish.

The seaweed known colloquially as nori in Japanese - used for making sushi - or karengo in Maori has been reclassified by an international team of scientists including NIWA's Dr Wendy Nelson.

New Zealand's geographic isolation and relatively recent colonization provide the opportunity for a unique genetic analysis of plant movement patterns to be explored.

Estuaries in New Zealand are experiencing sedimentation at higher rates than before humans arrived here: this represents a loss both for land and estuary productivity. We need to better understand what has been happening so that we can predict the future and fight these losses.

A significant threat to the biosecurity of New Zealand's freshwater habitats comes from plants that have been intentionally introduced.

A Ministry for Primary Industries-funded study has shown that grass carp, in enclosures, can be used as an effective means of controlling invasive plant species in our waterways.

NIWA is involved in research and consultation' aimed at improving the health of our freshwater systems.

A project funded by West Coast Regional Council has increased our knowledge of the role of phosphorus in determining water quality in Lake Brunner.

Many New Zealand lakes are suffering from nutrient enrichment, causing potentially toxic blooms of blue-green algae. NIWA is testing a range of methods to manage phosphorus release from lake sediments – including sediment-capping agents.

Gathering, eating and sharing wild kai (food) has always been a very important part of Māori culture and wellbeing - this research project aimed to characterise the risks associated with consuming kai collected from rivers, lakes and coastlines.