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The natural world. Looking pretty for 3.5b years.

Toxic Fog

Author: Hugh Bollinger/Friday, December 18, 2015/Categories: sustainability, environment

                                    Fog Collector Sampling Equipment (credit: FogNet at UCSC)

I lived on the California coast for many years and the "fog season" was always something I looked forward to typically in May-July in Southern California and almost any time from Monterrey north. Fog forms over cold ocean currents near coastlines. It is influenced by air temperature, topography, and wind conditions. It is a particularly common environmental feature of the entire coast of California. However, something has now become altered in this important atmospheric process, it isn't good, and bad consequences could result.

                                            Coastal California Fog Layer (credit: Wikicommons)

Professional and citizen-scientists using a University of California monitoring system called FogNet have sampled fog on the northern California coast from Monterrey to Eureka for two years. Their measurements have detected an unwanted bit chemistry attached to the fogs---toxic mercury.

Researchers from the Moss Landing Marine Laboratory and UCSC with support from the National Science Foundation made boat excursions to the California continental margin to to determine where the mercury might be originating. Sampling the water column, marine phyto-plankton, and sea bed sediments, they determined the powerful California Current was pulling dimethyl mercury from the depths and marine aerosols were converting the chemistry to methyl mercury in the fog.

Speaking at the American Geophysical Union meetings in San Francisco one researcher said: "when the fog moves ashore the mercury is deposited on the land. That’s the working model we've now developed."

Mercury is a toxic metal produced by coal-fired power plants, certain mining operations such as gold mining, and various other industrial chemistry processes. Any mercury pollution deposited in the oceans is from run-off where it can cause marine ecosystem damage. The metal is readily absorbed by plankton and moves up the food-chain in the blood of marine mammals, the tissues of salmon and other fish, and can cause severe neurological and reproductive problems in humans if ingested in high concentrations.

A video was produced to illustrate how mercury can be delivered to land via fog:

Additional research is needed to determine the amount of mercury being deposited along the coast and its health consequences. However, the now altered fogs are another good example of ecosystem
connections inherent to natural environments on which wildlife, plants, and humans depend.


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