Scientists studying quicksilver levels in glacial bears say that melting ocean ice has forced the bears to change their diets . The researchers published their report in the journalEnvironmental Science & Technology .
Mercury is all around us . Some of it occurs naturally in plants , fauna , and the soil . Some of it is our fault , the resultant role of industrial pollution from coal and other fuel .
Regardless of its source , it heap up in living thing the same room . midget animals eat plants hold in Hg , and the mercury stays in their body even after all the flora matter is gone . Then those flyspeck animate being are eaten by small animals , and on and on , forrader up the food chain . Apex predators like swordfish and shark areswimming clod of hydrargyrum , which is why we tell meaning women not to eat them .
For the same rationality , they should n’t wipe out polar bears , either ( although we would kind of wish to see them render ) . Previous tests on bears in the southern Beaufort Sea found alarmingly high atomic number 80 stratum in the animals ’ tomentum and body tissue — the result of the bear ’ diet of mercury - saturated ringed seals . Or theirformer diet , we should say .
Researchers followed Beaufort Sea bear from 2004 to 2011 , taking regular tissue paper and hair samples from sedated bears and by long - distance biopsy dart . Chemical psychoanalysis of the sample shew a clear and steady declination in mercury floor . Each class , the bears ’ body check 13 per centum less mercury .
But it ’s not as though these bears were getting 13 percent small . They were n’t rot away . So what had happened ?
It turns out their primary prey , ringed seals , had originate scarce . Ringed seals expend most of their time on sea internal-combustion engine . But as the sea ice disappeared , so did they . In answer , the bears change over their predatory attention to bearded seals and bowhead whales , both of which conduct less mercury . Even as their mercury levels dropped , the bear ' BMI increased , perhaps because they were rust more blubber from the turgid prey .
The authors note that the bear in their discipline might not represent all bear in that area . They could only take samples from the bears they could get hold along the glide . Less successful hunters might still have been struggling out at ocean .
They also say that the icy bear ’ fair game - switching is , deplorably , not a sustainable answer . We ’re not precisely experiencing a surplus of whales , here .
