The Transporter: Cloud Banks Carry Mercury
The towering redwood forests along California’s coast are known for the clammy fog that rolls in from the ocean almost every night. Now scientists have discovered an unwelcome stowaway in these cloud banks: mercury. Previous research had shown that fog sampled in and around Santa Cruz, California, contained the heavy metal mercury but no one knew the source. New results presented at the American Geophysical Union conference show that the mercury is likely coming from the ocean.
The minute amounts of mercury aren’t enough to harm someone walking around in the fog—you could find more mercury in a can of tuna, said atmospheric chemist Peter Weiss-Penzias. But fog is a big player in the central California coast’s water cycle. And since mercury accumulates in plants and animals, getting more concentrated as it moves further up the food chain, the pollutant’s presence poses a threat to the ecosystem.