Fool’s gold fertilising the oceans
according to new research published in Nature Geoscience.
The availability of iron is often a limiting factor in the growth of marine organisms such as bacteria and phytoplankton. Pyrite is an iron sulphide that is produced in large quantities by hydrothermal vents in the deep sea. Scientists previously believed that the particles of pyrite produced by the vents were solids that settled back to the sea floor, but according to the new study, which was carried out by scientists at the University of Delaware, a significant amount of the pyrite particles produced by the ‘black smokers’ have diameters 1,000 times smaller than that of a human hair.
Because the particles are so small, they remain in the water column and can be dispersed over large distances, rather than falling to the sea floor. And because the iron is bound up with sulphur, it doesn’t react rapidly with oxygen in sea water to form oxidised iron or ‘rust’. ‘As pyrite travels from the vents to the ocean interior and toward the surface ocean, it oxidises gradually to release iron, which becomes available in areas where iron is depleted so that organisms can assimilate it, then grow,’ said George Luther, one of the study’s authors. ‘It’s an ongoing iron supplement for the ocean – much as multivitamins
are for humans.’
July 2011
The availability of iron is often a limiting factor in the growth of marine organisms such as bacteria and phytoplankton. Pyrite is an iron sulphide that is produced in large quantities by hydrothermal vents in the deep sea. Scientists previously believed that the particles of pyrite produced by the vents were solids that settled back to the sea floor, but according to the new study, which was carried out by scientists at the University of Delaware, a significant amount of the pyrite particles produced by the ‘black smokers’ have diameters 1,000 times smaller than that of a human hair.
Because the particles are so small, they remain in the water column and can be dispersed over large distances, rather than falling to the sea floor. And because the iron is bound up with sulphur, it doesn’t react rapidly with oxygen in sea water to form oxidised iron or ‘rust’. ‘As pyrite travels from the vents to the ocean interior and toward the surface ocean, it oxidises gradually to release iron, which becomes available in areas where iron is depleted so that organisms can assimilate it, then grow,’ said George Luther, one of the study’s authors. ‘It’s an ongoing iron supplement for the ocean – much as multivitamins
are for humans.’
July 2011
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