This World Water Day, Wellesley scientists find that the teeth of the nerpa seal may hold the strongest evidence of the effects of decades of environmental pollution, nuclear testing, and climate change on Lake Baikal—the deepest, oldest, and most bio-diverse lake in the world.
March 21 marks World Water Day—and a fitting time to consider one of the most unique mammals in the Earth’s waters.
Victor Kantor courtesy of Wellesley College
A nerpa seal pictured in Siberia's Lake Baikal
The nerpa, also known as the Baikal seal, is the only seal that lives exclusively in fresh water. This earless seal can be found in just one place, Russia’s Lake Baikal, where it is at the top of the food web. And now, Wellesley scientists have found that the teeth of this particular seal may hold the strongest evidence of the effects of decades of environmental pollution, nuclear testing, and climate change on Lake Baikal—the deepest, oldest, and most bio-diverse lake in the world.
“The Baikal seal teeth are a chemical record of the lake,” said Marianne Moore, Wellesley Professor of Biological Sciences. By analyzing the chemical composition of hundreds of seal teeth, Professor Moore and her co-researchers, post-doctoral fellow Ted Ozersky and Wellesley student Xiu Ying (Annie) Deng ‘15, are working to reconstruct the Baikal seal’s diet and contaminant burdens over the last 80 years. The teeth were collected from ice harvested in the area by fellow scientists in Russia.
Baikal seals can live up to 40 and 50 years, and much like the rings of a tree trunk, the layers of dentine within their teeth can be studied and linked to environmental patterns and changes over a period of time. Moore, Ozersky, and Deng are looking for evidence of toxic metals such as uranium, mercury, cadmium, and zinc inside the teeth samples, which date back to the period before industrialization in the region.
Why not just measure these toxic elements in the water? Professor Moore explained that these metals show up at extremely low levels in the water. The teeth of the nerpa are actually better indicators due to biomagnification, the process by which the concentration of a substance increases with each level of the food chain. Because the Baikal seal is at the top of its food web, their teeth hold the best clues into the lake’s environmental past.
“Ultimately, the goal of our project is to study contamination levels in Lake Baikal as reflected by the seals, and to tie these patterns to changes in the watershed, such as the introduction of mining in the area, an increase in coal burning, and other environmental events,” said Dr. Ozersky.
Still early in the project, the Wellesley researchers have already made a surprising discovery: levels of some toxic metals such as uranium were higher in the mid 1970’s than in seals today. This suggests improving environmental conditions in the region. High levels of uranium in the mid 1970’s may represent the legacy of atmospheric nuclear testing that ended in 1980 in Asia.
Sofiya Cabalquinto | newswise
Man-made underwater sound may have wider ecosystem effects than previously thought
05.02.2016 | University of Southampton
Sluggish electrons caught in action
04.02.2016 | Max-Planck-Institut für Quantenoptik
Pollens, the bane of allergy sufferers, could represent a boon for battery makers: Recent research has suggested their potential use as anodes in lithium-ion batteries.
"Our findings have demonstrated that renewable pollens could produce carbon architectures for anode applications in energy storage devices," said Vilas Pol, an...
Automobiles increase the mobility of their users. However, their maneuverability is pushed to the limit by cramped inner city conditions. Those who need to...
Advance in biomedical imaging: The University of Würzburg's Biocenter has enhanced fluorescence microscopy to label and visualise up to nine different cell structures simultaneously.
Fluorescence microscopy allows researchers to visualise biomolecules in cells. They label the molecules using fluorescent probes, excite them with light and...
NASA's follow-on to the successful ICESat mission will employ a never-before-flown technique for determining the topography of ice sheets and the thickness of sea ice, but that won't be the only first for this mission.
Slated for launch in 2018, NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) also will carry a 3-D printed part made of polyetherketoneketone (PEKK),...
In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures. Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.
In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister...
02.02.2016 | Event News
26.01.2016 | Event News
26.01.2016 | Event News
08.02.2016 | Earth Sciences
08.02.2016 | Studies and Analyses
08.02.2016 | Health and Medicine