Dangerous levels of mercury in Arctic ecosystems could be having a harmful effect on Arctic fox populations, according to research published in PLOS One on 6 May.
Mercury exposure could have contributed to a catastrophic drop in Arctic fox populations on one Russian island, say the researchers.
The findings suggest that increasing levels of mercury in marine ecosystems could have a significant impact on land animals with a marine-based diet.
The team of Russian, German, and Icelandic scientists examined hair samples from inland and coastal populations of Arctic foxes, comparing data from populations in Russia and Iceland.
In particular they compared samples from Medny Island, part of the Commander Islands in the North Pacific, where the foxes eat a primarily marine-based diet of sea birds, to samples from the neighbouring Bering Island, where the foxes have a more diverse diet.
Between 1970 and 1980, the Arctic fox population on Medny Island collapsed mysteriously, declining from around 1000 foxes to approximately 100 today. “We started to look for different pathogens that might underline the cause of the poor condition and high mortality but we couldn’t find anything,” lead author Dr Gabor Czirjak from the Leibniz Institute for Zoo and Wildlife Research, told the BBC.
Instead, the authors say, they found high levels of mercury that matched the symptoms found in the Medny Island fox population.
Conservations efforts targeting inland populations of Arctic fox, and other animals, could therefore be more effective as coastal populations will have a greater exposure to mercury.
Mercury exposure is a particular problem in the Arctic region, with Nasa research suggesting that reductions in the amount of sea ice are contributing to the increase in mercury levels. Despite a
recent UN agreement to control the use of mercury and prevent its release into the environment, some models suggest that there will be a 25 percent increase [.PDF] in human emission by 2020 as compared with 2005.
