Algal bloom concentration measured as chlorophyll.
The recent activation of the Adelaide desalination plant and the coincidental toxic algal bloom causing the widespread deaths of marine fauna is cause for concern. As shown by the chlorophyll map above, the bloom including the toxic marine alga Karenia mikimotoi occurred close to the Adelaide plant which discharges brine and maintenance chemicals into a relatively sheltered nearshore environment. Notably, to reduce harmful impacts, dispersion jets are used to rapidly dilute brine and potentially toxic chemicals at the point of discharge. In doing so, the strong jets can mobilise sediments and release nutrients and previously dormant cysts of toxic algal species including algae causing the current devastating bloom. The disturbance to nearshore sediments, and conditions favourable for rapid increase in the growth of toxic algae such as elevated temperature, nutrients, and sunlight, present plausible causes of the bloom. Such conditions are likely to be more prevalent with climate change. Public statements which exclude or aim to diminish the role of desalination discharge as a cause are inconsistent with desalination plants elsewhere in the world which have been associated with harmful algal blooms. This underscores the considerable risk presented by a proposed desalination plant off Port Lincoln which is adjacent to a designated aquaculture zone. It is generally recommended that desalination plants be situated on high energy coastlines away from valuable biological resources.