On 1 July 2025, NIWA merged with GNS Science to become Earth Sciences New Zealand.

Salinity in estuaries

Figure 4: Kaipara Harbour, water salinity (practical salinity units) and Coloured Dissolved Organic Matter (CDOM, absorbance at 340 nm) values measured along transects away from the Hoteo, Kaipara and Wairoa River mouths.