Sutton Salt Lake is New Zealand’s only inland salt lake, with water about half as salty as seawater. Formed in a windy cool-temperate maritime climate, the lake is distinctly different from most of the world’s saline lakes that form in arid continental settings. The site receives c. 500 mm/year rainfall and the surface evaporation rate is high (c. 700 mm/year) because of frequent strong winds. Sediments on the lake floor are derived by rain and wind erosion of the surrounding bedrock. The lakes water is derived entirely from rainwater, rather than groundwater. The lake salinity is derived from marine aerosols in rainwater concentrated by repeatedly filling, evaporating and refilling. The lake occupies an enclosed shallow basin in the schist rock landscape. (www.otago.ac.nz/geology)
With considerable variety of saline habitats around its margin and in adjacent slightly saline boggy depressions it is home to an endemic aquatic species.