Sydney harbors deadly diet for sea creatures

Apr 07, 2008

Contaminated seaweeds in Sydney Harbour could be threatening the small animals that feed on them, according to a new study revealing that the harbour's seaweeds have the world's highest levels of copper and lead contamination.

Up to 75 percent of the offspring of small crustaceans that feed on a common brown seaweed, for example, are killed when they are exposed to copper at levels found in some parts of the harbour, UNSW laboratory and field experiments have shown.

The UNSW study sampled seaweed from 10 bays within the harbour, ranging from 3km to 11km from Sydney Heads. Concentrations of copper, lead and zinc in a species of brown seaweed found in Woolloomooloo Bay, Balls Head Bay and Rushcutters Bay equal or exceed levels found in the Hong Kong Islands and Brazil's Sepetiba Bay, which are among the world's most heavy metal-contaminated waterways.

Heavy metals such as copper, lead and zinc find their way into Sydney Harbour from stormwater runoff, industrial waters and motorised watercraft. These seaweeds "bioaccumulate" metals inside their tissues and scientists use them to monitor environmental pollutants.

Published in an upcoming issue of the journal Environmental Pollution, it is the first investigation of the geographic relationship between metal contamination in seaweeds and the crustaceans that feed on them.

The study reveals that high concentrations of copper in one seaweed species (Padinacrassa) were associated with a low abundance of grazing amphipods - small shrimp-like creatures - that feed on algae. These creatures are highly abundant in all marine habitats: on average there are some 6,000 animals per square metre of algal bed in Sydney Harbour.

"The habitats that we sampled within Sydney Harbour contain among the highest concentrations of metals yet identified in brown seaweeds," says study lead author, Dr David Roberts.

"In seven of the 10 sample harbour sites, we measured copper concentrations in one seaweed species that exceeded levels known to threaten small crustaceans. These concentrations exceed all previously scientifically reported levels."

Source: University of New South Wales

Explore further: Hydroelectric dams drastically reduce tropical forest biodiversity

Related Stories

Recommended for you

Should we all escape to the country during a heatwave?

8 minutes ago

A University of Birmingham research project has highlighted the potential health impacts of heatwaves in urbanised areas. By modelling the 2003 heatwave the researchers were able to identify areas where city centres were ...

NASA maps beach tar from California oil pipeline spill

1 hour ago

When an on-land pipeline ruptured north of Santa Barbara, California, on May 19—spilling 105,000 barrels of crude oil onto Refugio State Beach and about 21,000 gallons of oil into the Pacific Ocean in the ...

Not all plastics equal

1 hour ago

Ever buy a fish at a pet store that died within days of being put in an aquarium at home?

Carbon capture and storage safety investigated

2 hours ago

A significant step has been made for potential Carbon Capture and Storage (CCS) deployment, with the publication of the results from the world's first experiment into the realistic simulation of potential ...

Australia hails 'tremendous' UN barrier reef decision

6 hours ago

Australia Thursday hailed a United Nations decision to keep the Great Barrier Reef off its in danger list as "tremendous", but activists warned more must be done to improve the marine park's health.

Cities, regions, demand bigger climate say

14 hours ago

Leaders of city and regional governments gathered Wednesday in the French city of Lyon, in the grips of a western European heatwave, to demand a bigger stake in the global push to curb global warming.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.