Happy Pinniped (aka seals) Friday y’all! Did you know that was a thing? Actually it’s not, I made it up…
Anyhow, my post today is about a recently published study by researchers at the University of CA, Santa Cruz. They determined that elevated levels of toxic mercury in the waters near Año Nuevo State Reserve (Pescadero, CA) came from the molted skins of northern elephant seal (Mirounga angustirostris). Elephant seals undergo an annual “catastrophic molt” where they shed their entire skin and hair. Comparisons with coastal areas with no marine mammal populations showed mercury levels in waters near Año Nuevo were twice as high during breeding season and 17 times higher during molting season.
The form of mercury found in these waters is methyl mercury which comes from industrial emissions. It is highly toxic and can easily be absorbed into the bodies of marine organisms. Methyl mercury concentrations increase as it travels up the food chain from marine organism to marine organism. As an apex predator, the northern elephant seal can have incredibly high levels of methyl mercury throughout it’s body. An unfortunate toxic cycle is revealed-fish absorb methyl mercury, seal eats fish, seal molts, methyl mercury is back in the water.
The results of this study can be found in the Proceedings of the National Academy of Sciences of the United States of America. I expect future research will look at other areas within the northern elephant seal distribution and could expand to the southern elephant seal and other seal species as a possible source of mercury.
For More Information:
University of California, Santa Cruz News Center: http://news.ucsc.edu/2015/09/mercury-elephant-seals.html
USGS Western Ecological Research Center (link to related PNAS article): http://www.werc.usgs.gov/ProductDetails.aspx?ID=5295
About the Illustration:
Pencil, watercolor, and micron pens-When I read about this study I immediately had an image of a heavy metal loving elephant seal in mind for a future post. A little humor keeps us sane… This image is available via Redbubble.
Special Note: I made a few changes to my blog so it is a bit more user-friendly. Yay! Please check it out and let me know what you think!