Correct Response: C. The slight decrease in salinity of North Atlantic surface waters has reduced the water's density. This change likely results from increased freshwater influx from Greenland's melting ice sheet. A substantial drop in salinity will reduce the rate at which North Atlantic surface waters sink. Since this sinking water pulls the Gulf Stream's warm water northward as part of the ocean's thermohaline circulation, this change could alter the region's climate. Salinity does affect water pH (A), but it is not the primary concern of scientists studying changes in salinity in the region. The change in salinity would be unlikely to directly affect precipitation in the region (B) and although it would increase the formation of sea ice (D) in far northern areas, this is not a concern for scientists studying the phenomenon.
