Algal Bloom

Mr BASHAM (Finniss) (17:10): Again, my question is to the Minister for Climate, Environment and Water. Has the government explored mitigation measures such as clay flocculation to treat the algal bloom and, if not, why not?

The Hon. S.E. CLOSE (Port Adelaide—Deputy Premier, Minister for Climate, Environment and Water, Minister for Industry, Innovation and Science, Minister for Workforce and Population Strategy) (17:11): I would like to talk about the clay method, which is very topical at the moment because PIRSA and SARDI have invited Dr Anderson to come over, who is one of the people who published a paper about a year ago on the use of clay.

Just to give a little bit of background on that for people, we are talking not about pure clay as it might be dug up from the land; to use that to address algal blooms takes an enormous amount of clay and it is not particularly effective. There is, however, an approach that has been used in China to modify clay by putting additives into clay, including aluminium, to make it more effective in what is called flocculating, which is the capacity to form a heavy curtain over algae and make it sink to the bottom of the sea.

There are reasons why you would be cautious about doing that. One is that if you are putting an additive in, you are putting an additive into the ocean: for example, aluminium, which we need to be very careful about. Another is that where there have been some trials on this with bivalves—and for us, of course, that is particularly important as bivalves are oysters and mussels—clay can retard the growth of those animals. That is not necessarily a reason to not use it but it is something to be aware of, and when you are adding a whole lot of sediment to a water body that can change the nature of the ecology there.

South Australia has a very diverse biodiversity; in fact, I am not sure if people realise that we have a broader range of biodiversity in our marine environment than in the Great Barrier Reef. The Great Southern Reef is an extraordinary reef and houses an extraordinary variety of biodiversity. We also have very high-quality biodiversity in a very good marine environment. China is the only place that has used this approach in open water to deal with Karenia mikimotoi in the ocean, and the Chinese marine environment, I would venture to say, is neither as diverse nor as healthy as the South Australian one. Certainly, we wouldn't rush to simply adopt an approach that has been undertaken by China, nor have other parts of the world.

The US has undertaken a trial and Dr Anderson is one of the people, as I said, who published the paper about a year ago on that trial, which involved water in tanks on land for a 72-hour period with three species of marine life to see how they were affected: a clam, a sea urchin—and another one that will come back to me shortly. That trial did indicate that it was pretty effective at dealing with Karenia in that short period, that there was perhaps some retardant of growth for the bivalve, but that otherwise they felt it went reasonably well.

So the US, although it hadn't previously approved the use of clay, has indicated that the next time there is a Karenia brevis outbreak in Florida that they will permit a one acre area of ocean to have a dose of this clay.

We are talking about something that is exciting but experimental and one that requires approvals. One of the approving authorities, the most important one, is the APVMA which is a commonwealth authority. We have been in touch with them. What is occurring during this week is that we are looking into whether we can do a trial, probably on land or in a very confined water body, to see what the impact might be on our marine environment, and we thank Dr Anderson for coming over to help us discuss that.