Pure white Arctic Ivory Gulls has seen its population reduced to just 20% of historic levels since the 1980’s. Only 500 breeding pairs of the gulls survive today.
There is 45 times more mercury in those gulls today than in the past based on 80 samples that included museum specimens dating back more than 130 years.
The beautiful Ivory Gull, is now classified by the International Union for Conservation of Nature as threatened, but it is facing a newly identified threat – rising mercury levels in Arctic.
According to a new research by Canadian ornithologist Alex Bond the population of ivory arctic gulls have declined in number by more than 80 per cent since the 1980s and he and co-authors have noted environmental contaminants, especially mercury, as one of the primary reasons behind the decline.
The scientists examined fresh and museum Ivory Gull breast feathers and measured the mercury content of 80 ivory gulls dating from 2007 to as far back as 1877. The findings were startling as far as mercury concentrations were concerned. The researchers found that despite no changes in the gull’s diet, methyl mercury concentrations were 45 times higher than 130 years ago.
Researchers note that ivory gull eggs have the highest mercury content of any Arctic bird, with the Canadian gulls having the highest concentration across the entire species’ range. This is likely because they scavenge marine animal carcasses, which are exposed to high levels of mercury.
Ivory Gull canaries and the coal mine(d)
Mercury from natural sources exists everywhere in the marine environment at low and constant levels. Life has evolved and adapted to those low-level traces of mercury. But there is a new source of mercury in the world and that is in the ash and smoke that comes from the burning of coal. This new coal-fired mercury is flooding the world’s oceans with deadly mercury. The new mercury builds up in the ocean food chain and rises to dangerous deadly levels in larger sea life such as big fish and sea mammals.
The problem is especially acute in ice-bound regions where over the long winter months mercury particulates from distant coal-fired power plants accumulates on the ice. When the short growing season arrives and the ice melts a massive dose of mercury enters the ocean at a time where biological activity is at a maximum. It’s the biological transformation of particulate mercury into toxic methyl mercury that is makes this sudden surge of Arctic mercury so deadly.
Gulls that are known for their scavenger habits feeding on carcasses of dead sea life are most vulnerable of all the sea birds to the toxic effects of mercury. The carcasses of the dead marine mammals and large fish they scavenge upon contains high levels of methyl-mercury.
“Mercury is an increasing problem for Arctic wildlife as more is emitted by coal power stations and other anthropogenic means,” said Bond. “We wanted to see if the high mercury levels experienced by the gulls was a recent phenomenon, and possibly determine if it was linked to their decline over the past three decades.”
Bond further said that Mercury is accumulating in the ivory gulls about twice as quickly as it is in other Arctic animals and added that if the current trends continue, the bird is likely to be extinct in less than 50 years.
The findings have been published in journal Proceedings of the Royal Society of London B- Biological Sciences and the paper is titled “Rapidly increasing methyl mercury in endangered ivory gull (Pagophila eburnea) feathers over a 130 year record.”