Mercury levels in the ocean have more than tripled thanks to people

Human activities, such as mining and fossil fuel combustion, have more than tripled the amount of mercury in the ocean.

Woods Hole Oceanographic Institution researchers measured mercury levels during recent expeditions to the Atlantic, Pacific, Southern and Arctic oceans.

The findings, which have been published in the journal Nature, will help researchers better understand how and when inorganic mercury compounds become toxic and enter the marine food web.