National Reference Stations

What are National Reference Stations?

National Reference Stations provide fundamental baseline information used to understand how large-scale, long-term climate change and variability is affecting Australian coastal seas. A current network of seven National Reference Stations are currently in operation in Australian coastal waters, of which three are long-term locations, Maria Island (Tasmania), Port Hacking (New South Wales) and Rottnest Island (Western Australia). The remaining four National Reference stations, including Darwin (Northern Territory), Yongala (Great Barrier Reef), Kangaroo Island (South Australia) and North Stradbroke Island (Queensland) are newer additions to the network of National Reference Stations, increasing the ability to monitor Australian coastal waters.

In addition to the continuous monitoring of physical oceanic properties of the moorings, these sensor-based observations are combined with vessel-based biogeochemical sampling on a monthly basis (for most locations).

Key Data Streams

The National Reference Stations collect observations of both physical and biogeochemical variables to characterise the ocean environment and to understand fundamental biological processes within the environment. Core physical variables observed include temperature, salinity, dissolved oxygen, nutrients, turbidity, carbon, phytoplankton (both direct, and via an optical proxy for chlorophyll a), and zooplankton.

Understanding these variables necessitates observations at NRS sites being undertaken through the water column, from surface to seabed. Observations are sensor‐based and supplemented by vessel‐based biogeochemical sampling (and laboratory analysis) at minimum frequencies required to provide appropriate resolution for core variables.

As the resources required to sustain physical and biogeochemical observations over the long term are significant, the NRS Network consists of the minimum number of sites necessary to provide a national multi‐decadal baseline. At these timescales, ocean processes are operating at space scales in the thousands of square kilometres, and the IMOS NRS is hence a sparse network of well‐ instrumented, single‐point, reference sites, strategically positioned around Australia’s coastline.

David Hughes