Giving Compass' Take:

• The California fog is bringing high levels of mercury that is not a risk to humans but does have a significant impact on the mammals that live on land near the coasts such as pumas and mountain lions. 

• Human activity and influence already impacts pumas along the coast. How can donors help curb these negative effects?

• Read about how you can make a difference in animal welfare. 

Researchers find that the neurotoxin is carried in by coastal fog, deposited on the land, and then makes its way up the food chain where it is approaching toxic thresholds in pumas.

Along the coast of California, Mother Nature performs one of her most poetic tricks: Coastal fog. It slinks in from the Pacific and rolls up canyons, it swaths San Francisco in clouds, and it hydrates the world's tallest trees. It mingles the smell of the sea with that of chaparral and redwoods; it is so precious they make vodka from it! The world may know California for its sunshine, but many Californians cherish the coastal fog as their true mascot.

And it was in this fog that an atmospheric chemist was riding his bike, about a decade ago, when the proverbial light bulb went off.

"I was riding through this absolute fogstorm, with water dripping off my glasses, and I just wondered, 'What's in this stuff?'" Peter Weiss-Penzias recalled. Thinking that mercury might de-gas out of the ocean and turn up in the fog, he gathered samples and sent them to a lab.

"The lab called me, saying they'd have to re-run the tests, because they didn't believe the numbers," said Weiss-Penzias.

Thus begun a field of studying pollutants in coastal fog; now, all these years later, Weiss-Penzias has led the first study tracing the atmospheric source of super-toxic methylmercury in the terrestrial food web, all the way up to a top predator. And the results are ... really depressing.

The University of California, Santa Cruz (UCSC) notes, "Concentrations of mercury in pumas [AKA mountain lions] in the Santa Cruz Mountains were three times higher than lions who live outside the fog zone. Similarly, mercury levels in lichen and deer were significantly higher inside the fog belt than beyond it."

Read the full article about coastal fog by Melissa Breyer at TreeHugger.