The matter transport component assesses how Commonwealth environmental water has contributed to the transport/export of salt, nutrients and phytoplankton through the Lower Murray River. This indicator models concentrations and transport of salt, dissolved and particulate nutrients and microalgae/phytoplankton biomass (chlorophyll a).
Salinity is the measure of total dissolved salts. It is strongly influenced by flow, groundwater inputs, evapo-concentration and intrusion of seawater in estuarine habitats. Undoubtedly, salinity is an important parameter governing the distribution and abundance of aquatic biota.
Dissolved inorganic nutrients are the ones readily assimilated by biota for growth and survival. Nitrogen, phosphorus and silica are particularly important because they control the productivity of aquatic ecosystems. Particulate organic nutrients (such as nitrogen and phosphorus) are those incorporated into the issue of living and dead organisms.
Chlorophyll a is a measure of phytoplankton biomass, which is an important primary producer sustaining the food webs of riverine ecosystems.
All three components are strongly influenced by flow. Flow plays a major role exporting salt, transporting dissolved nutrients, from dried sediments and dead organic matter and increasing in phytoplankton productivity.
The Coorong Habitat component assesses if and how water for the environment improves Ruppia tuberosa and fish habitats in the Coorong, through reducing salinity and increasing water levels.
The Coorong Habitat component utilises the salinity concentrations and water level modelled data, as well as other environmental conditions, to estimate the extent of fish and Ruppia habitats in the Coorong.
Ruppia tuberosa is an important aquatic plant (macrophyte) which provides habitat for fish and food for herbivorous birds in the Coorong. The germination and growth of Ruppia is known to be influenced largely by salinity and water level, and consequently by flow regimes through the Coorong barrages (Kim et al. 2013). Salinity is also known to strongly influence the extent of estuarine fish habitat as well as influence the fish assemblage present in the Coorong. Key fish species are Mulloway, Black bream, Greenback flounder, Yelloweye mullet, Congolli, Tamar goby and Smallmouth hardyhead.
The study is led by the limnologist Professor Justin Brookes from In Fusion Consulting / University of Adelaide.