Monday, May 31, 2010

Birds Spread Heavy Metals to Arctic Ponds

A recent study found that coastal seafood-eating birds can carry toxins inland.
The team collected sediment cores from two ponds on a small island in the Canadian Arctic that is home to the nests of two kinds of seabirds: Arctic terns, which feed primarily on fish, and common eider ducks which feed mainly on mollusks. The researchers analyzed the pond sediment for metals and other indicators of the birds' activity.

They found significant differences between the samples that aligned with the birds' diets. There were higher concentrations of metals such as mercury and cadmium in the sites inhabited by terns, while the nearby eider site recorded higher amounts of lead, manganese, and aluminum. The patterns of metals in the sediment cores matched those recorded in the different bird species' tissues....

"The seabirds are obviously not directly to blame for the elevated metal concentrations in the ponds," says team member Jules Blais, a biology professor from the University of Ottawa. "They are simply carrying out their natural behaviours and lifecycles, but have become unwitting vectors of pollutants in an increasingly industrial age."
An earlier study found a similar pattern in Northern Fulmars, so this result is not at all surprising.