SA government cites ecosystems, upwelling proximity in opposing offshore wind

South Australia’s government has opposed a 200-kilometre-long ocean wind farm zone off its southeast coast, citing concerns about commercial fisheries and environmental impacts.

In a statement, the state’s deputy premier and climate, environment and water minister Susan Close expressed concern at the possible impact of a wind farm built south of Port Macdonnell, 460km southeast of Adelaide. The SA rock lobster industry also expressed concerns about a potential development.

And given the wind farm would not provide energy to South Australia, the state government has requested the zone cease at the state boundary, though the development would occur in federal waters.

“The South Australian Government is committed to renewable energy projects that improve our state’s energy security, but we cannot support ones that have the potential to cause significant harm to local industries and the environment. This is particularly the case when they have no net benefit to South Australians,” Close said.

“The zone’s proximity to our marine parks and the Bonney upwelling is also of significant concern given the rich biodiversity in the region.”

The Bonney upwelling is a highly stable nutrient cycle occurring off the Bonney coast – an area spanning Australia’s south shoreline from Cape Jaffa to Portland.

Upwelling processes are vital to marine ecosystems, where wind and the planet’s rotation displace surface water and cause deep, cold water beneath to ‘well up’ to replace it. This replacement water is nutrient-dense, providing the fuel – along with exposure to sunlight – for phytoplankton to grow and act as the vital foundation of marine food webs.

“Upwelling is a process that actually lifts nutrients and rich water into the light layers – in the oceans light only penetrates 50 meters – and in order to produce marine life, you need light and unique nutrients. Nitrogen is the most important part,” says Associate Professor Dr Jochen Kaempf, a physical oceanographer based at Flinders University.

“And upwelling is a physical process that lifts nutrient-rich water from below, into the light zone, and that kicks off the marine food chain.

“It starts off with the production of phytoplankton, and then it actually passes through the marine food chain with zooplankton, small fish and then, indeed, if you have high spatial concentrations of [these], then it attracts whales and tuna and larger pelagic species into a region.”

Advocates for rock lobster fisheries welcomed the move, citing the potential for “uncertainties and stress” for the industry and nearby fishing communities. Executive officer for the Rock Lobster Advisory Council Nathan Kimber wants to see fishing areas excluded from the offshore wind zone.

“We now hope that [Federal Climate Change and Energy] Minister Bowen will listen to the submissions made by the South Australian Government and our industry and amend the proposed Southern Ocean offshore energy zone to exclude any waters that overlap with our fishery boundaries,” he said.

While built projects typically need to consider environmental impacts, human activities can have disrupting influences on ecosystems on land and at sea.

When it comes to the construction of any extensive infrastructure – whether a wind project, oil rig or offshore platform – disruption to nearby ecosystems should be expected.

“Although it must be said, it depends on where it will be established to be established on habitat that’s already destroyed on the sandy bottom or will it be established on biodiverse, temperate rocky reefs? That can make a big difference,” says Professor Ivan Nagelkerken, a marine ecologist at the University of Adelaide.

He points to the risk of large supportive platforms being built for wind turbines upending marine ecosystems and the potential disruption caused by noise pollution, sedimentation or toxin release from the infrastructure.

Underwater noise impacts from construction can also disrupt other, larger organisms like whales and dolphins that migrate through the region.

There can be benefits. Large human-built infrastructure can attract species over time, acting like artificial reefs for some marine life. But Nagelkerken warns that the ultimate risk for both animal species and humans is the disruption to local processes that diminishes fishery productivity.

“Artificial habitats wouldn’t necessarily have the same productivity as a natural habitat,” Nagelkerken says.

The risk, he says, is that attracting fish and producing fish are very different phenomena.

“If they [artificial habitats] attract fish from the surrounding environment, they don’t actually contribute to productivity, they just redistribute where the fishes are.”

“And ultimately, we’re interested in food productivity: that dictates our fisheries catches: rock lobsters, all type of commercial and recreationally important fishery species, whether the shellfish, fin fish, and so on. They’re all connected.”

But both Nagelkerken and Kaempf point to the elephant in the room: carbon emissions. Carbon is being absorbed by the oceans at greater levels, and with this comes the risk of acidification and temperature increase. In turn, this can influence the ability of marine ecosystems to support life, and ultimately productivity.

Reducing carbon is the primary means of slowing these effects, but that requires changes to major emissions industries – like energy. So wind farms generating electricity fall into the bigger picture for maintaining ecosystems and productivity.

“There’s always concerns, but there’s always priorities,” says Kaempf. “These things are actually meant for a good purpose, to produce green energy… It’s the big question about which direction do we go in, and there might be negative impacts.”

“It’s more about, very well establishing what the pros and cons are, and if it has to happen, selecting the right side, the right research to assess the impacts, trying to mitigate the effects as much as possible.”