Asian Mercury Crossing the Ocean

NOAA

Fight disinformation: Sign up for the free Mother Jones Daily newsletter and follow the news that matters.


A fascinating new study documents for the first time how mercury gets from smokestacks in Asia to tuna on dinner tables in America. Scientists sampled Pacific Ocean water from 16 sites between Honolulu and Alaska, then constructed a computer model linking atmospheric emissions, transport and deposition of mercury, and ocean circulation.

Their findings published in Global Biogeochemical Cycles show how mercury originating from fossil-fuel-burning plants and waste-burning plants in Asia falls into the Pacific Ocean near the Asian coastline. The mercury-enriched waters are then carried by large ocean currents east towards North America.

The study documents for the first time something of the mysterious process by which mercury becomes methylmercury in the ocean. The simple version: Mercury rained down from the atmosphere is taken up by phytoplankton living in sunlit waters. When these plankton die they rain down into the depths where they’re decomposed by bacteria. The process of decomposition turns mercury into methylmercury.

Methylmercury is an environmental neurotoxicant that rapidly bioaccumulates in the foodweb, eventually concentrating in top-tier predators like tunas and humans. Some 40 percent of human exposure to mercury in the US comes from eating tuna hunted in the Pacific Ocean. Pregnant women who consume mercury-laden seafood can pass on life-long developmental effects to their children.

Since the Industrial Revolution anthropogenic mercury levels in the atmosphere have risen threefold, with corresponding increases in terrestrial and aquatic ecosystems. This study found mercury levels in water samples rose an alarming 30 percent between the mid 1990s and 2006. That’s hardly the end of it though. The authors predict another 50 percent increase in the Pacific by 2050 if emission rates continue as projected.

Yet another reason to we can’t tread water on fossil fuels. Too bad Australia’s Kevin Rudd just did a spineless jellyfish backflip on climate change. As if the economy is disconnected from the environment.
 

AN IMPORTANT UPDATE

We’re falling behind our online fundraising goals and we can’t sustain coming up short on donations month after month. Perhaps you’ve heard? It is impossibly hard in the news business right now, with layoffs intensifying and fancy new startups and funding going kaput.

The crisis facing journalism and democracy isn’t going away anytime soon. And neither is Mother Jones, our readers, or our unique way of doing in-depth reporting that exists to bring about change.

Which is exactly why, despite the challenges we face, we just took a big gulp and joined forces with the Center for Investigative Reporting, a team of ace journalists who create the amazing podcast and public radio show Reveal.

If you can part with even just a few bucks, please help us pick up the pace of donations. We simply can’t afford to keep falling behind on our fundraising targets month after month.

Editor-in-Chief Clara Jeffery said it well to our team recently, and that team 100 percent includes readers like you who make it all possible: “This is a year to prove that we can pull off this merger, grow our audiences and impact, attract more funding and keep growing. More broadly, it’s a year when the very future of both journalism and democracy is on the line. We have to go for every important story, every reader/listener/viewer, and leave it all on the field. I’m very proud of all the hard work that’s gotten us to this moment, and confident that we can meet it.”

Let’s do this. If you can right now, please support Mother Jones and investigative journalism with an urgently needed donation today.

payment methods

AN IMPORTANT UPDATE

We’re falling behind our online fundraising goals and we can’t sustain coming up short on donations month after month. Perhaps you’ve heard? It is impossibly hard in the news business right now, with layoffs intensifying and fancy new startups and funding going kaput.

The crisis facing journalism and democracy isn’t going away anytime soon. And neither is Mother Jones, our readers, or our unique way of doing in-depth reporting that exists to bring about change.

Which is exactly why, despite the challenges we face, we just took a big gulp and joined forces with the Center for Investigative Reporting, a team of ace journalists who create the amazing podcast and public radio show Reveal.

If you can part with even just a few bucks, please help us pick up the pace of donations. We simply can’t afford to keep falling behind on our fundraising targets month after month.

Editor-in-Chief Clara Jeffery said it well to our team recently, and that team 100 percent includes readers like you who make it all possible: “This is a year to prove that we can pull off this merger, grow our audiences and impact, attract more funding and keep growing. More broadly, it’s a year when the very future of both journalism and democracy is on the line. We have to go for every important story, every reader/listener/viewer, and leave it all on the field. I’m very proud of all the hard work that’s gotten us to this moment, and confident that we can meet it.”

Let’s do this. If you can right now, please support Mother Jones and investigative journalism with an urgently needed donation today.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate