Indicator: CO-60 Sea salinity

Data

The Navy’s Meteorological and Oceanic Services reports the range of salinity levels of Australian waters at major towns around Australia.

Annual range of salinity in coastal waters at selected towns
Coastal Town Annual change in salinity
Albany 0.4
Adelaide 0.7
Bateman's Bay 0.1
Broome 0.6
Cairns 1.3
Darwin 0.7
Dunk Island 1.5
Hobart 0.4
Macquarie Island 0.2
Melbourne 0.2
Perth 0.2
Sydney 0.1
Townsville 1.3

Derived from Source: National Oceanographic Data Center 1999, World Ocean Atlas 1998 - Coastal Sea Surface Temperatures, viewed 8 Jun 2006, http://www.metoc.gov.au/products/data/aussst.html

What the data mean

A small selection of these towns from around Australia show little annual variation in salinity. Areas of major coastal developments, such as capital cities, do not seem to show much difference from less developed areas. However, slightly greater variations in salinity do seem to occur in tropical, high rainfall areas such as Cairns, Townsville and Dunk Island.

Data Limitations

The analysis is based on historical data as at 1998. To monitor whether salinity levels are changing these data would need to be updated on an annual basis.

Issues for which this is an indicator and why

Coasts and Oceans — Condition of the ocean and coastal waters - Climatic and carbon dioxide factors 

Melting freshwater glacial ice as a result of global warming could potentially cause major and long term changes to ocean salinity, and potentially have very significant implications for marine ecosystems.

Other indicators for this issue:

Coasts and Oceans — Condition of the ocean and coastal waters - Water quality 

Changes in coastal ocean salinity may also occur as a result of changes in freshwater runoff from the land. Localised changes in salinity may be indicative of a change in water quality.

Other indicators for this issue:

Coasts and Oceans — Direct pressure of human activities on coasts and oceans - Direct pressure of coastal activities (other than shipping and fishing) 

Localised changes in salinity may occur as a result of runoff of pollution or significant increases in freshwater outfalls from the land. These changes may have localised ecological impacts, favouring some species that are present in coastal ecosystems relative to others.

Other indicators for this issue:

Coasts and Oceans — Contributions and pressures between the coasts and oceans and the atmosphere - Climate and carbon dioxide 

Changes in salinity, due to melting freshwater ice as a result of atmospheric climate change could potentially have both direct effects on marine life and result in changes to currents which have further impacts on climate affecting marine life.

Other indicators for this issue:

Biodiversity — Pressures on biodiversity - Climate variability 

Changes in sea salinity are likely to result from changes in global climate and are therefore an indirect indicator for these changes.

Other indicators for this issue:

Biodiversity — Pressures on biodiversity - Pressures on marine biodiversity: pressures of coastal activities 

In addition to being a potential outcome of climate change, localised changes in sea salinity can result from increases in freshwater discharges from human settlements and activities.

Other indicators for this issue:

Atmosphere — Climate variability and change -Greenhouse 

Changes in sea salinity may result from the melting of glaciers and may therefore be indicative of anthropogenic climate change due to the emission of greenhouse gases and the loss of greenhouse sinks.

Other indicators for this issue: