Hungry birds spread contaminants to High Arctic
“Don’t blame the birds – the blame is purely in the South.”
When Cape Vera fulmars pluck a tasty squid or fish from the ocean, they’re quick to fly the fresh snack back home to their young.
But this seafood, which has nourished these birds and their young for millennia, is also transporting contaminants back to the land, says a study published last week in the journal Science.
Since 2003, a team of researchers, led by Mark Mallory of the Canadian Wildlife Service in Iqaluit, has been studying a colony of 20,000 fulmars on Cape Vera on Devon Island and the impact of climate change on the birds.
Cape Vera is an isolated place that’s considered to be far from pollution by industrial and agriculture contaminants such as mercury and DDT.
But researchers have found the Cape Vera bird colony is actually sitting in the middle of a High Arctic “hot spot” of contamination.
That’s because the fulmars nest on cliffs, which are ringed by freshwater ponds at the bottom. As the birds digest their seafood, full of contaminants carried north by water and air currents, their contaminant-laden excrement flows down into the ponds below.
And the contaminants don’t stay in the ponds, either: they travel further into the food chain as birds eat water insects, and foxes eat the birds
Contaminant levels in sediments from 11 ponds studied at Cape Vera are up to 60 times greater than those found at nearby sites that aren’t affected by seabird populations.
The study says the high levels of persistent organic pollutants and mercury found in the ponds “dwarf” the amount carried to the Arctic by water and air.
“Don’t blame the birds – the blame is purely in the South. The poor birds are just feeding and doing their thing, but inadvertently, they’ve been transporting these contaminants,” said John Smol, a member of the research team who returned this week from the High Arctic.
Scientists have known for years that seabirds carry contaminants because they are at the top of the food chain.
“But the notion that the Arctic is under threat because of seabirds is nonsense,” Mallory said in an interview from Resolute Bay.
In fact, Cape Vera may be a rare place in the Arctic because seabirds usually nest over the oceans. This means most contaminants picked up by nesting seabirds return directly to the water.
But the study’s findings at Cape Vera underline the need for more environmentally-sound practices in the South, says Jules Blais from the University of Ottawa, the lead author of the Cape Vera study.
Blais has also looked at how contaminants are distributed through fish, such as salmon or char. Contaminants can end up concentrated in specific places because the fish return up freshwater streams from the ocean to spawn and die in large numbers, funneling contaminants into the environment.