Australian Desalination Plant a Boon for Area Fish

(CN) – In a change of pace, an industrial plant in Australia has made a group of reef fish happy and social.

More fish assemble near an outlet of the Sydney Desalination Plant during the discharge of a hypersaline solution than before or after discharge. (Photo by Mclennans Diving)

For centuries, the industrial activities of humans have polluted the environment and oceans, but a study published Wednesday in the journal Environmental Science and Technology says the largest desalination plant in the world attracts fish through the discharge of very salty water.

Desalination is the resource-intensive process of removing minerals from saltwater to make drinking water. In the race for more drinking water, the ocean is the last frontier for humans and yet there are so many variables on what is done to marine life during this process.

Australia saw one of the worst periods of drought in the early 2000s. While the drought peaked in 2006, conditions lingered through 2009 according to the nation’s Bureau of Meteorology.

Enter the Sydney Desalination Plant which began operating in 2010 and today generates up to 66 million gallons of potable water per day as the capital faces an ongoing drought.

Consider that massive intake of seawater and the amount of minerals that need to be filtered out. According to the study published in Environmental Science & Technology, the plant’s output of minerals is released above a rocky reef about 328 yards offshore and 26 yards below the surface.

And the local marine population can’t get enough of it.

Over a seven-year period, researchers from the National Marine Science Center and Marine Ecology Research Center at Southern Cross University in Australia recorded marine activity before and after desalination activity.

They were also able to compare their results during a period when the plant was not operating. The study authors found commercially important species were three times more plentiful around the plant’s outlets. Generally, fish are attracted to disturbances in the water column because it could mean more food.

The discharge from the plant “enhanced fish assemblages” including fish varieties that live close to the ocean floor and one-spot pullers that live off rocky coasts, which primarily feed on zooplankton according to the study authors.

They acknowledge they’re not aware how desalination discharge could influence the local population of zooplankton or whether the plant’s outlets are any more advantageous to the natural reefs. They note, however, they are aware that desalination discharge has been found to negatively impact marine fauna, like the reduction of echinoderms – starfish, sea urchins and other marine animals.

In their study, researchers used scuba gear and video recordings of marine activity with 360-degree spin segments. Results showed after the desalination discharge stopped, fish activity returned to what it was before that brine uptick.

“Notably, there was a clear step-up in the richness of fish species around the outlet in the middle of the discharging period that coincided with a step down in the reference sites,” write the study authors.

Researchers say their results point to the added benefit of a well-designed marine infrastructure and discharge that can enhance local fishing opportunities, but also boost species richness.

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