Featured Research

from universities, journals, and other organizations

Cracked sea ice stirs up Arctic mercury concern

Date:
January 15, 2014
Source:
NASA/Jet Propulsion Laboratory
Summary:
Vigorous mixing in the air above large cracks in Arctic sea ice that expose seawater to cold polar air pumps atmospheric mercury down to the surface, finds a NASA field campaign. This process can lead to more of the toxic pollutant entering the food chain, where it can negatively affect the health of fish and animals who eat them, including humans.

Cloud plumes from cracks of open water in the Arctic sea ice cover.
Credit: University of Hamburg, Germany

Vigorous mixing in the air above large cracks in Arctic sea ice that expose seawater to cold polar air pumps atmospheric mercury down to the surface, finds a NASA field campaign. This process can lead to more of the toxic pollutant entering the food chain, where it can negatively affect the health of fish and animals who eat them, including humans.

Scientists measured increased concentrations of mercury near ground level after sea ice off the coast of Barrow, Alaska, cracked, creating open seawater channels called leads. The researchers were in the Arctic for the NASA-led Bromine, Ozone, and Mercury Experiment (BROMEX) in 2012.

"None of us had suspected that we would find this kind of process associated with leads," said Son Nghiem, a scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Nghiem is the BROMEX principal investigator and a coauthor of a paper reporting the discovery published in Nature on Jan. 15.

The mercury-pumping reaction takes place because open water in a lead is much warmer than the air above it, according to study lead author Chris Moore of the Desert Research Institute, Reno, Nev. Because of that temperature difference, the air above the lead churns like the air above a boiling pot. "The mixing is so strong, it actually pulls down mercury from a higher layer of the atmosphere to near the surface," Moore said. The mixing, marked by dense clouds spewing out of the leads, extends up into the atmosphere about a quarter-mile (400 meters). Moore estimates this may be the height where the mercury pumping occurs.

Almost all of the mercury in the Arctic atmosphere is transported there in gaseous form from sources in areas farther south. Scientists have long known that mercury in the air near ground level undergoes complex chemical reactions that deposit the element on the surface. Once the mercury is completely removed from the air, these reactions stop. However, this newly discovered mixing triggered by leads in the sea ice forces down additional mercury to restart and sustain the reactions.

Leads have become more widespread across the Arctic Ocean as climate change has reduced Arctic sea ice cover. "Over the past decade, we've been seeing more new sea ice rather than perennial ice that has survived for several years. New ice is thinner and saltier and cracks more easily. More new ice means more leads as well," said Nghiem.

To understand the effects of the leads, the team took ground-based measurements of mercury and other chemical species over the frozen Chukchi Sea and over snow-covered land. They used images from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra satellite to observe sea ice and a National Oceanic and Atmospheric Administration model of air transport to gain insight into what was upwind of their mercury measurements.

Co-author Daniel Obrist, also from the Desert Research Institute, said, "The 'aha' moment came when we combined the surface measurements with the satellite data and model. We considered a bunch of chemical processes and sources to explain the increased levels of mercury we observed, until we finally realized it was this pumping process."

Nghiem points out that this new finding has come at a turning point for action on Arctic mercury pollution. The Minamata Convention, a global treaty to curb mercury pollution in which Arctic vulnerability is particularly noted, has been signed by 94 nations since it was opened for signatures in Oct. 2013. Arctic mercury pollution originates almost entirely in nations as far south as the tropics, from sources such as wildfires, coal burning and gold mining. "Once the Minamata Convention has been ratified and becomes international law, we expect this work to help assess its effectiveness," Nghiem said.

The study also includes co-authors from Environment Canada, Toronto; the U.S. Army Cold Regions Research and Engineering Laboratory, Fort Wainwright, Alaska; and the University of Bremen, Germany, and was jointly funded by NASA, Environment Canada and the Desert Research Institute.

For more information on BROMEX, visit: http://airbornescience.jpl.nasa.gov/highlights/bromine-ozone-and-mercury-experiment-bromex .

The California Institute of Technology in Pasadena manages JPL for NASA.


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. The original article was written by Carol Rasmussen, NASA Earth Science News Team. Note: Materials may be edited for content and length.


Journal Reference:

  1. Christopher W. Moore, Daniel Obrist, Alexandra Steffen, Ralf M. Staebler, Thomas A. Douglas, Andreas Richter, Son V. Nghiem. Convective forcing of mercury and ozone in the Arctic boundary layer induced by leads in sea ice. Nature, 2014; DOI: 10.1038/nature12924

Cite This Page:

NASA/Jet Propulsion Laboratory. "Cracked sea ice stirs up Arctic mercury concern." ScienceDaily. ScienceDaily, 15 January 2014. <www.sciencedaily.com/releases/2014/01/140115132202.htm>.
NASA/Jet Propulsion Laboratory. (2014, January 15). Cracked sea ice stirs up Arctic mercury concern. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/2014/01/140115132202.htm
NASA/Jet Propulsion Laboratory. "Cracked sea ice stirs up Arctic mercury concern." ScienceDaily. www.sciencedaily.com/releases/2014/01/140115132202.htm (accessed August 30, 2014).

Share This




More Earth & Climate News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Volcano Erupts on Papua New Guinea

Raw: Volcano Erupts on Papua New Guinea

AP (Aug. 29, 2014) Several communities were evacuated and some international flights were diverted on Friday after one of the most active volcanos in the region erupts. (Aug. 29) Video provided by AP
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Scientists Have Figured Out Why Rocks Move In Death Valley

Scientists Have Figured Out Why Rocks Move In Death Valley

Newsy (Aug. 28, 2014) The mystery of the moving rocks in Death Valley, California, has finally been solved. Scientists are pointing to a combo of water, ice and wind. Video provided by Newsy
Powered by NewsLook.com
Big Waves, Minor Flooding from Hurricane

Big Waves, Minor Flooding from Hurricane

AP (Aug. 27, 2014) Thundering surf spawned by Hurricane Marie pounded the Southern California coast Wednesday, causing minor flooding in a low-lying beach town. High surf warnings were posted for Los Angeles County south through Orange County. (Aug. 27) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

More Coverage


Arctic: Mercury Deposition and Ozone Depletion, Linked to Sea-Ice Dynamics

Jan. 15, 2014 Scientists have established, for the first time, a link between Arctic sea ice dynamics and the region's changing atmospheric chemistry potentially leading to increased amounts of mercury ... read more
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins