Navigation Links
New study shows fish respond quickly to changes in mercury deposition

Reducing atmospheric mercury emissions should quickly reduce mercury levels in lake fish, according to a three-year study published this week in the Proceedings of the National Academy of Science. The study showed that an increase in mercury loading at rates relevant to atmospheric deposition resulted in a significant increase in methylmercury production and accumulation in fish in only three years.

This is good news. It means that a reduction in new mercury loads to many lakes should result in lower mercury in fish within a few years, said Cynthia Gilmour, scientist at the Smithsonian Environmental Research Center and a co-investigator in the study.

While recent federal and state regulations aimed at reducing mercury levels in fish require reductions in mercury emissions, the potential effectiveness of these controls and the time frame of the response were previously unknown.

Some have speculated that it could take decades to see the impact of emissions reductions on mercury levels in fish. Centuries of human-derived mercury releases to the atmosphere have resulted in elevated amounts of mercury in sediments and soils across most of the globe. If this historical mercury contamination contributes substantially to mercury in fish, reductions in current emissions may have little impact in the foreseeable future.

The study, Mercury Experiment to Assess Atmospheric Loading in Canada and the United States, found that methylmercury (the type that accumulates in fish) was more readily produced from newly deposited mercury than from historical mercury contamination already buried in lake sediments. This means that methylmercury in lakes should decline quickly if mercury deposition is reduced.

Additionally, the study team found that mercury added directly to the lake surface was rapidly accumulated into fish, while essentially none of the mercury deposited to the lakes watershed was found in fish after three years. This suggests that lakes should exhibit a two-phase response to load reductions. Initially, mercury in fish should decline rapidly (within years) as deposition to the lake itself is reduced. A slower, more prolonged decline (perhaps decades long) should follow in response to decreases in mercury deposition in the watershed.

The study was accomplished through an experimental addition of mercury to a small lake and its watershed at the Experimental Lakes Area, a Canadian federal research reserve. ELA is a remote, protected area set aside for the long-term study of lakes and watersheds, where deposition of mercury is low compared with sites in Europe and the United States. For three years, the mercury load to the lake ecosystem was increased by roughly three timesbringing the total annual mercury load up to a level comparable to that on the east coast of the United States. This large-scale, whole ecosystem approach was important because the complex behavior of ecosystems can be difficult to predict from smaller-scale experiments.

To distinguish the mercury they added to the lake from the existing mercury in the study ecosystem, the researchers used a sophisticated analytical method that had never been used in this way at such a large scale. Mercury in the natural environment is made up of seven stable isotopes that do not vary much in proportion to one another. To dose the lake, the scientists used mercury that is heavily enriched in one of those isotopes, enabling them to trace the mercury they added through the complex environmental mercury cycle.

Gilmour and her colleagues Andrew Heyes (University of Maryland) and Robert Mason (University of Connecticut) focused on one of the key processes in that cycle, the microbial production of methylmercury, which is produced by natural bacteria in sediments and soils and accumulates in food webs.

It will be important to monitor mercury during the next 20 years to make sure that emissions regulations are effective in reducing mercury deposition, Gilmour said. If they are, the study suggests that reductions in emissions will result in fairly rapid reduction in risk to people and to ecosystems.


Contact: Kimbra Cutlip

Related biology news :

1. Bioartificial kidney under study at MCG
2. Novel Asthma Study Shows Multiple Genetic Input Required; Single-gene Solution Shot Down
3. W.M. Keck Foundation funds study of friendly microbes
4. Yellowstone microbes fueled by hydrogen, according to U. of Colorado study
5. Emory Study Tests Bone Marrow Stem Cells to Improve Circulation in Legs
6. UCLA Study Shows One-Third of Drug Ads in Medical Journals Do Not Contain References Supporting Medical Claims
7. Study Demonstrates Gene Expression Microarrays are Comparable and Reproducible
8. Study Links Ebola Outbreaks To Animal Carcasses
9. Genome-wide mouse study yields link to human leukemia
10. Breakthrough Microarray-based Technology for the Study of Cancer
11. NYU Study Reveals How Brains Immune System Fights Viral Encephalitis
Post Your Comments:
(Date:5/12/2016)... May 12, 2016 , a ... the overview results from the Q1 wave of its ... wave was consumers, receptivity to a program where they ... a health insurance company. "We were surprised ... says Michael LaColla , CEO of Troubadour Research, ...
(Date:4/28/2016)... SAN FRANCISCO and BANGALORE, India ... part of EdgeVerve Systems, a product subsidiary of Infosys (NYSE: ... service provider, today announced a global partnership that ... convenient way to use mobile banking and payment services. ... Mobility is a key innovation area for financial services, but ...
(Date:4/26/2016)... , April 27, 2016 ... the  "Global Multi-modal Biometrics Market 2016-2020"  report to ... ) , The analysts forecast the ... CAGR of 15.49% during the period 2016-2020.  ... number of sectors such as the healthcare, BFSI, ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... , June 23, 2016 ... Review, 2016;12(1):22-8 Published ... the peer-reviewed journal from touchONCOLOGY, Andrew D ... cost of cancer care is placing an increasing ... of expensive biologic therapies. With the patents on ...
(Date:6/23/2016)... ... June 23, 2016 , ... ... at the Pennsylvania Convention Center and will showcase its product’s latest features from ... also be presenting a scientific poster on Disrupting Clinical Trials in The Cloud ...
(Date:6/23/2016)... , ... June 23, 2016 , ... ... new line of intelligent tools designed, tuned and optimized exclusively for Okuma CNC ... in Chicago. The result of a collaboration among several companies with expertise in ...
(Date:6/23/2016)... June 23, 2016 ... report to its pharmaceuticals section with historic and ... and much more. Complete report on ... pages, profiling 15 companies and supported with 261 ... . The Global Cell ...
Breaking Biology Technology: