Three times as much mercury has been found in mountain lions in the Santa Cruz Mountains than in their inland brethren, and the likely culprit is coastal fog, a first-of-its-kind study by UC Santa Cruz has found.

The fog is apparently pulling mercury out of the ocean and dripping it over the coastal mountains, a potentially lethal problem for cougars because it bioaccumulates in their fat and could eventually contribute to their demise, the study, published Tuesday in the journal Scientific Reports, concluded.

Mercury poisoning is known to cause memory and motor coordination problems and has been shown in studies in the Florida Everglades to cause reproductive problems in pumas. Mercury can come from natural sources, but researchers said most of the mercury currently in the atmosphere comes from burning coal.

“What makes it a cause for concern is that this could be repeating itself in foggy coastal regions across the world,” said Chris Wilmers, an associate professor of environmental studies at UC Santa Cruz and a co-author of the study. “Elsewhere, where you have seen high levels of mercury were either ocean-derived or stream-derived, (but) this is a completely terrestrial food chain.”

The study tested the hair and whiskers of dozens of mountain lions, young and old, living on the coast and in inland areas, including the Klamath, Sierra Nevada and Cascade ranges, with a few samples taken from museums for comparison. Lab analysis found an average of three times more methylmercury in the Santa Cruz mountain lions than in cougars living in less-foggy inland regions.

 

 

 

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