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

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>