I live in North Sydney, just up the hill from Luna Park and the iconic Harbour Bridge.
It’s good to learn that the horror stories about the quality of Sydney Harbour’s water are actually true.
The waters of the harbour are actually teeming with life of all kinds. But rising levels of heavy metals in the ecosystem is threatening its stability. Copper, lead and zinc find their way into the waterways from stormwater runoff, industrial waters and motorised watercraft. These heavy metals are being found in large quantities in seaweed at a number of locations on the harbour, even higher than notoriously contaminated around the Hong Kong Islands and Brazil’s Sepetiba Bay.
This won’t necessarily kill the seaweed. But its worse for the whole ecosystem. The UNSW studies show that areas with heavily contaminated weeds are devoid of grazing amphipods. This could be considered good news for the weed (and possibly accumulation could be selected for), but less grazing amphipods means less food to support higher predators, like fish. The ecosystem collapses from top to bottom. Not good.