Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Eggs Show Arctic Mercury Cycling May Be Linked to Ice Cover

24.01.2011
An international research team working with National Institute of Standards and Technology (NIST) scientists at the Hollings Marine Laboratory (HML) in Charleston, S.C., has suggested for the first time that mercury cycling in the flora and fauna of the Arctic may be linked to the amount of ice cover present.

Their study* is the latest work reported from the Seabird Tissue Archival and Monitoring Project (STAMP), a multiyear joint effort of NIST, the U.S. Fish and Wildlife Service (USFWS), the U.S. Geological Survey (USGS) and the Alaskan Bureau of Indian Affairs to track trends in pollutants in northern marine environments using seabird eggs.

Overall mercury levels in northern environments have been documented for some 20 years. However, the new study marks the first time that the tracking has been done using a sophisticated analysis of mercury isotopes (forms of the same atom that have different atomic masses) and an effect called "mass-independent fractionation" or MIF.

MIF is a relatively unusual change in the relative abundance of different isotopes of the same element (fractionation) that can be the result of photochemical reactions. Determining the relative amount of the MIF isotopes of mercury is considered valuable because the data can be used to trace the reactions in nature that led to the fractionation—and in turn, provide a better understanding of how the reactions work and how they impact the cycling of mercury in the environment.

Ultraviolet radiation from sunlight can fractionate mercury on the ocean surface via a process known as photodegradation. Laboratory research has shown that this reaction preferentially selects for some isotopes of mercury to move into the atmosphere while others become more abundant in the ocean. Plankton absorb the water-borne mercury, fish eat the plankton, and finally, sea birds eat the fish and pass the ingested mercury into their eggs. Therefore, the eggs are key tissues for mercury monitoring. For the current study, field groups made up of biologists and native Alaskans (for whom seabird eggs are a food source) collected eggs laid by murres, a bird species that nests year-round in three coastal regions of Alaska.

Examination of murre eggs from the northernmost nesting areas where sea ice exists all year long revealed lower amounts of MIF mercury isotopes than in eggs collected from sites in southern Alaska where there is no ice cover. Conversely, the mercury in eggs from nests near ice-free seas reflected significantly greater effects of mass-independent fractionation. The researchers believe that ice prevents UV light from reaching the mercury, effectively suppressing photodegradation.

With the potential for global warming to dramatically reduce Arctic sea ice in the future, the relationship between ice cover and distribution of mercury in the environment is obviously an important one to investigate further. The international research team next plans to use its seabird egg isotope monitoring system to distinguish the sources of mercury contamination in coastal areas to those from oceanic waters. For this study, eggs will be collected along Alaska's Norton Sound that receives runoff from the Yukon River—including high concentrations of cinnabar, the ore from which mercury is derived—and compared to eggs from remote island colonies that are more influenced by atmospheric and oceanic mercury sources.

Teaming on this study with NIST scientists at the HML were staff from the USFWS Alaska Maritime National Wildlife Refuge (Homer, Alaska), Environment Canada (Saskatoon, Saskatchewan, Canada), the Labotatoire des Mécanismes et Transferts en Géologie (Toulouse, France) and the Institut Pluridisciplinaire de Recherche sur ¾Environnement et les Matreriaux (Pau, France). Financial support for the research was provided by NIST, the French Centre National de la Recherche Scientifique and a grant from the French Agence Nationale de Recherche.

The HML is a unique partnership of governmental and academic agencies including NIST, NOAA's National Ocean Service, the South Carolina Department of Natural Resources, the College of Charleston and the Medical University of South Carolina.

* D. Point, J.E. Sonke, R.D. Day, D.G. Roseneau, K.A. Hobson, S.S. Vander Pol, A.J. Moors, R.S. Pugh, O.F.X. Donard and P.R. Becker. Methylmercury photodegradation influenced by sea ice over in Arctic marine ecosystems. Nature Geoscience. Published online Jan. 16, 2011.

Michael E. Newman | Newswise Science News
Further information:
http://www.nist.gov

More articles from Earth Sciences:

nachricht Predicting unpredictability: Information theory offers new way to read ice cores
07.12.2016 | Santa Fe Institute

nachricht Sea ice hit record lows in November
07.12.2016 | University of Colorado at Boulder

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>