Territory Stories

Darwin Harbour in good health



Darwin Harbour in good health


Westra Van Holthe, Willem

Political affiliation

Country Liberals


Media Releases for 12th Assembly 2012 - 2016; Media Releases; ParliamentNT






Made available by via the Publications (Legal Deposit) Act 2004 (NT)




Oceans; Marine life

Publisher name

Northern Territory Government

File type



Issued as a Media Release

Copyright owner

Northern Territory Government

Parent handle


Citation address


Related items

https://hdl.handle.net/10070/528211; https://hdl.handle.net/10070/528213

Page content

8 4.1.3. Complementary parameters pH. This is a measure of the concentration of hydrogen ions [H+] and is an indicator of water alkalinity or acidity. Changes in pH affect metal solubility and toxicity, and an organisms ability to absorb minerals and nutrients, and respiratory efficiency of fish and aquatic invertebrates. Marine waters are normally alkaline. Temperature. The water temperature is a significant measure as it affects other parameters such as the amount of oxygen dissolved in the water, the rate of photosynthesis of plants, and growth of aquatic organisms. Salinity. Salinity is a measure of the total concentration of ions (mainly inorganic salts) in the water. Salinity affects aquatic organisms depending on their adaptability to a narrow or wide range of salinities. River inflows dilute marine waters to be less saline. 4.2 Water Quality Objectives The Water Quality Objectives for Darwin Harbour recommend the water quality that supports the maintenance of the ecosystem, and are designated under Part 7 of the Water Act as a local guideline level in accordance with the National Water Quality Management Strategy and ANZECC guidelines (Fortune, 2010). Water quality data for each Harbour reporting zone were compared with WQOs as benchmarks to evaluate water quality condition. The Report Card grades were assessed with respect to the WQOs for Darwin Harbour. The median (50th percentile) was calculated for each Report Card water quality parameter, and compared against the WQOs shown in Table 5. If the median was less than the WQO, then the data complied with the WQO, and was assigned a green tick in the Report Card. However, if the median exceeded the WQO, then this was considered to be a departure, and may warrant investigation as to the cause of the exceedance. An exceedance can be caused by the natural variability of water quality and be unrelated to pollution. The Report Card marks this as a fail, symbolised by a red cross.