THE high level of the nerve toxin methylmercury in the Arctic is a result of global warming and the melting of sea ice, Harvard University researchers have established.
Methylmercury causes damage to the central nervous system, particularly in unborn babies.
Researchers said when fresh water from the melting Arctic sea ice met the salty ocean, the water deeper down had a higher salinity than that closer to the surface.
This stratification of salinity allowed “fluffy organic matter”, that would normally sink to the bottom of the sea, to stay in one place in the water. They referred to this as “neutral buoyancy”: the matter could not float up or down.
This layer is called “marine snow”. Bacteria stuck in this zone perform a complex chemical process that turns naturally occurring mercury into “a deadly and readily accumulated methylmercury”.
Zooplankton are attracted to this layer of marine snow and go…
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