Deployments

Southern Australia IMOS field surveys started in 2008 and have been refined from the dense set of transects typically undertaken until 2013 (Figure 1) below to the 3 transect lines for 2014/2015 shown in Figure 2 below (These three transects cover inflows from the GAB including dense water outflows of winter) as well as along and cross shelf transects to monitor for outflows from Spencer Gulf and upwelling from Kangaroo Island. During these field surveys, CTD cast profiling is undertaken along with mooring deployments at which  sampling of biogeochemical tracers was undertaken. Southern Australia IMOS enjoys a record of not loosing any moorings in over 50 field cruises.

Southern Australia IMOS has serviced three mooring sites continuously which are:

  • National Reference Station Kangaroo Island (NRSKAI) - 2008-current
  • South Australian Mooring Coffin Bay (SAM5CB) - 2009-12, 2014-current
  • South Australian Mooring Spencer Gulf (SAM8SG) - 2009-current
Figure 1: Southern Australia IMOS survey locations for years 2011/2013. Blue dots are CTD cast sites, green dots are biological sampling sites, red rings are mooring locations, red star is the Southern Australia IMOS national reference station site for the southern shelves. The two moorings SAM2CP (Cabbage Patch) and SAM6IS (Investigator strait) were only maintained in 2008-2010 and 2009 respectively.

The field program associated with these moorings for 2014/2015 is shown in Figure 2 below.

Figure 2: Southern Australia IMOS survey locations for years 2014/15. Blue dots are CTD cast sites, green dots are biological sampling sites, red rings are mooring locations, red star is the Southern Australia IMOS national reference station site for the southern shelves.

In addition to the above Coffin Bay, Spencer Gulf and Kangarioo Island sites, a further five sites have had moorings deployed over the years indicated in the following:

  • South Australian Mooring Cabbage Patch (SAM2CP) - 2008-10
  • South Australian Mooring Canyon (SAM4CY) - 2009-10
  • South Australian Mooring Investigator Straight (SAM6IS) - 2009
  • South Australian Mooring Deep Slope (SAM7DS) - 2009-14
  • South Australian Mooring Mid Slope (SAM3MS) - 2011-13

More precise mooring dates are listed below. The locations of all moorings are shown in Figure 1 above and listed in Table 1 below.

For the 2011-2013 period, five moorings were deployed (Figure 1 above) with the addition of SAM3MS on the 200 m isobath and SAM7DS on the 500 m isobath. Data from both moorings showed currents at these depths to be dominated by weak mesoscale eddies and due to difficulties of servicing (large waves and unprotected vessel shelter),  both were discontinued.

Following the reduction in resources for the 2015/2017 period, a corresponding reduction was made to the field program as shown in Figure 3 below: the CTD casts to the Coffin Bay mooring SAM5CB have been discontinued.

Figure 3: Southern Australia IMOS survey locations for years 2015/16 and forward to 2016/17. Blue dots are CTD cast sites, green dots are biological sampling sites, red rings are mooring locations, and red star is the Southern Australia IMOS national reference station site for the southern shelves.

Table 1. Mooring locations and nominal depths

Mooring site Longitude °E Latitude °S Nominal Depth (m) Status
NRSKAI 136.44771 35.83593 110 Currently serviced
SAM1DS 136.2432 36.5161 ~500 Discontinued
SAM2CP 135.68682 35.26925 100 Discontinued
SAM3MS 135.904 36.1459 170 Discontinued
SAM4CY 136.85502 36.5199 120 Discontinued
SAM5CB 135.0098 34.9275 95 Currently serviced
SAM6IS 136.5998 35.5002 85 Discontinued
SAM7DS 135.8439 36.1809 ~500 Discontinued
SAM8SG 136.694 35.25 50 Currently serviced

More details of mooring deployment dates can be downloaded as an excel sheet and are colour coded as:

 

Mooring Recovered and data available.

 

Mooring Deployed but not yet retrieved.

 

Future Deployments

 

 

Discontinued Mooring

 

 

Mooring not deployed

 

 

 

SARDI’s research vessel R.V. Ngerin is generally used for deployments and retrievals and hosts a winch for CTD and Niskin bottle samples as well as a sea  crane (HIAB) for mooring deployments and retrievals. The vessel has a crew of four and can accommodate six scientific staff.

Mooring recovery from the Ngerin
RV Ngerin
Ana and Paul prepare to undertake a CTD cast