Elemental mercury at submarine hydrothermal vents in the Bay of Plenty, Taupo volcanic zone, New Zealand

Hot springs in active geothermal areas such as Yellowstone National Park, t he Geysers geothermal field in California, and the Taupo volcanic zone in N ew Zealand are notably enriched in the trace metals Au, Ag, As, Sb, and Hg. Such near-surface hot springs have formed many of the world's important de posits of gold and silver and some of the largest deposits of mercury. The majority of these are associated with continental geothermal systems in sub aerial environments. Here we report the discovery of active mercury-deposit ing hot springs in a submarine setting, at nearly 200 m water depth, within the offshore extension of the Taupo volcanic zone of New Zealand. These ve nts contain the first documented occurrence of elemental mercury on the sea floor and provide an important link between offshore hydrothermal activity and mercury-depositing geothermal systems on land. The discovery has impli cations for mercury transport in sea-floor hydrothermal systems and undersc ores the importance of submarine volcanic and geothermal activity as a sour ce of mercury in the oceans.