Development of a diatom-based transfer function for lakes and streams severely impacted by secondary salinity in the south-west region of Western Australia

Abstract

The association of diatom assemblages to salinity was studied in 95 lakes and streams ranging from freshwater to hypersaline in the south-west of Western Australia. The relationship between environmental variables and species composition was explored using canonical correspondence analysis (CCA) and partial CCA. Salinity was shown to account for a significant and independent amount of variation in the diatom data, enabling a transfer function to be developed based on the final dataset, which consisted of 89 sites and 150 diatom taxa. The most successful model was derived using tolerancedownweighted weighted averaging. Summary statistics showed that the transfer function performed very well with a high coefficient of determination and low prediction errors that remained high after the crossvalidation method of jackknifing (r apparent 2 = 0.97 and r jackknifed 2 = 0.89). This suggests that salinity can be accurately predicted using relative abundances of diatoms, and the model can now be applied to paleolimnological reconstructions. However, the transfer function also provides the basis for use in future biomonitoring studies to detect increases in salinity for lakes and streams most at risk, as well as to evaluate the success of remediation measures implemented to secondary salinised systems.

A diatom dataset and diatom-salinity inference model for southeast Australian estuaries and coastal lakes

“…Salinity has previously been found to be the overriding environmental variable influencing Australian diatom communities and diatom-salinity (or -conductivity) relationships have been described (e.g. Hodgson et al 1997;Blinn and Bailey 2001;Gell et al 2002;Philibert et al 2006;Saunders et al 2007;Tibby et al 2007;Taukulis and John 2009). With the exception of Hodgson et al (1997) and Saunders et al (2007), none of these studies were conducted in coastal ecosystems.…”

“…Large-scale environmental problems have arisen due to upstream river regulation, water extraction for irrigation, salinization, enhanced sedimentation rates, modifications of openings to the sea, urbanization of coastal catchments, acidification and eutrophication (SoE 2006;Fluin et al 2007;Taukulis and John 2009). Management efforts are increasingly focused on alleviating environmental problems (SoE 2006).…”

Effects of Temperature and pH on the Growth of Sargassum linearifolium and S. podacanthum in Potassium-Fortified Inland Saline Water

“…The SGR of the Sargassum in this trial, were at adult stages, at 20-22°C is higher than the adult stage of S. muticum (Yamauchi, 1984) but is much lower than the juvenile S. horneri (Choi et al, 2007) and juvenile S. muticum (Hales and Fletcher, 1989) at 15°C, presented the lower SGR of adults thalli and juvenile, which is similar to S. horneri (Lee et al, 2009). This implies a limitation of this study to lower temperatures, where more than 60% of WA inland saline ground water has the temperature lower than 20°C (Taukulis and John, 2009).…”

“…The S. linearifolium also needs K + -fortified at similar K + concentration in OW to sustain its growth in ISW (Bui et al, 2017b). In southwest WA, while the pH of OW is stable from 7.8-8.2, salinity from 35.5-36.5 (Hoang et al, 2016) and temperature of 22.0-32.0°C (Martin-Smith, 1993), the pH, salinity and temperature of ISW in the wheat belt of WA are generally varied by the depth and location of the groundwater (Nurmi et al, 1988;Nulsen, 1997;Taukulis and John, 2009). The pH varies from 3.9 to 9.7 in the wheat belt of WA (Nulsen, 1997;Taukulis and John, 2006), or 7.4 at 35 ppt in Broome (Lee, 1997;Taukulis and John, 2006).…”

“…The salinity of inland water in WA varies from 0 to 320 ppt and two-thirds of those areas has salinity 5-40 ppt (Mazor and George, 1992), which is suitable for the growth of seaweed, including Sargassum (Hwang et al, 2006;Jie et al, 2008). The temperature of ISW in WA is from 6.3-28.1°C with an average of 17.7°C (Taukulis and John, 2009). The pH and temperature are the two environmental factors that strongly influence the growth and heavy metal biosorption of Sargassum spp.…”