Deployments

The regional moorings are located off Perth, clustered near the Perth Canyon and the Two Rocks Line.  The Two Rocks Line initially contained five moorings deployed in July 2009, which transect the continental shelf north of Perth from the 50m to the 500m isobath.  Around the Perth Canyon, two slope moorings located near the 500 m isobath and one shelf mooring in 200 m water at the head of the canyon, monitor processes in and around the canyon, were deployed in January 2010.

Primarily these moorings were thermistor strings (some with ADCPs) allowing the structure of the Leeuwin Current on the shelf to be inferred. With the contribution of CSIRO capital expenditures, the moorings were enhanced to have ADCPs and salinity and biogeochemical sensors. Two of the moorings also sample biogeochemical parameters. 

In 2014 there was a national mooring review which resulted in the consolidation of the Western Australia mooring to four sites. The Two Rock transect was reduced to three moorings at 100m, 200m, and 500m isobaths and the Perth Canyon to one mooring at the head of the canyon.

All past and present moorings are maintained on a 6-monthly service roster during which delayed mode data in collected.

Original mooring deployment plan off Perth.
Currently deployed moorings off Perth.

The CSIRO Division of Fisheries and Oceanography commenced coastal monitoring programs around Australia to establish a long term data series in the 1940s and 50s. For Rottnest Island collecting of biogeochemical samples (BGC), from the western end of the island began in 1951 and continued until 2009 where with the advent of IMOS, the sampling was bolstered by an in situ mooring program, becoming one of the National Reference Stations. Under IMOS, there are actually two mooring structures anchored to the sea floor. Firstly, a biogeochemical mooring which consists of two Wetlabs Water Quality Monitors (WQMs), that record temperature, salinity, dissolved oxygen and fluorescence for one minute bursts every 15 minutes. Two Seabird SBE 37 temperature loggers are placed at intervals between the main WQM sampling instruments. A second mooring system featuring a 600 kHz RDI Sentinel ADCP system provides a continuous data streams of shelf currents. Water samples are collected monthly at the Station.

Esperance and Ningaloo stations were similarly configured, though they were discontinued in 2009.

Ningaloo National Reference Station Location
Esperance National Reference Station Location
Niskin Bottle rosette being armed for deployment.
CSIRO technician Mark Snell preserving fresh samples. Image credit: R. Crossing CSIRO.