Causes of Light Attenuation In Nine New Zealand Estuaries

The optical properties of a waterbody determine the underwater light climate for plant growth, as well as important aspects of its appearance. Purpose: To determine the optical properties and the constituent composition of nine northern NZ estuaries.

Data includes beam attenuation coefficient, diffuse attenuation coefficient, turbidity, suspended solids, and dissolved yellow substance. Sites were sampled Dec 1988 – March 1989. Surveyed estuaries within the Waikato Region are: Aotea, Kawhia, Raglan, Tairua, Whangapoua, Whitianga.

9 estuaries in northern NZ

Aotea – 2668217, 6352522, NZMG, 1:20000, POINT Kawhia – 2666524, 6344382, NZMG, 1:20000, POINT Raglan – 2672551, 6376298, NZMG, 1:20000, POINT Tairua – 2765063, 6462322, NZMG, 1:20000, POINT Whangapoua – 2745181, 6493816, NZMG, 1:20000, POINT Whitianga – 2752078, 6481712, NZMG, 1:20000, POINT

Dec 1988 – March 1989.

Samples were taken near the estuary mouth with visits timed to coincide with neap tides and within 1.6 hours of low tide. A stratified sampling regime was used. Observations were also made at Raglan throughout a full tidal cycle on one occasion. Frequency of collection: Each estuary was sampled on one to five occasions during the summer.

Not reported Gaps in collection: Not reported Data quality: Not reported Attribute accuracy: Not reported Completeness: Heavy rainfall in late December 1988 resulted in markedly depressed salinities at Tairua and Whitianga, but not at the four other estuaries sampled within a few days of this event. The optical properties of these floodwaters are described, but otherwise the relevant results were excluded from the analyses reported here.

scientific paper, electronic

Land use and harbour management

? Sensitivity/Confidentiality: ?

Finished