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The smallest gold-diggers in the world
Bacteria found in Australian mines help gold grains to form.
Richard Van Noorden
Prospectors looking for gold nuggets have swarms of tiny helpers: bugs that take up toxic gold complexes from the soil and spit out pure gold on to the grains around them. Research published today provides strong evidence that bacteria known to produce gold in the laboratory do their trick in the wild too.
Impure gold, mixed with silver and copper, is found in the veins of minerals such as quartz, sometimes in such low concentrations as to be invisible. More obvious to the casual prospector are the highly enriched 'secondary grains' or nuggets found in river beds and soil. It is thought that these may be formed by weathering processes that either leach out the silver and copper metals, or wash the gold into solution so it can accumulate elsewhere.
Frank Reith of the Australian National University in Canberra and his colleagues have shown that microbes play a role too.
Geologists in the field have seen bacterial structures on gold grains before, and microbiologists in the laboratory have shown that many types of bacteria will deposit gold and other metals from solution. But the link between bacteria and gold deposits was tenuous. Now Reith and his team have bridged the divide.
Bacteria found in Australian mines help gold grains to form.
Richard Van Noorden
Prospectors looking for gold nuggets have swarms of tiny helpers: bugs that take up toxic gold complexes from the soil and spit out pure gold on to the grains around them. Research published today provides strong evidence that bacteria known to produce gold in the laboratory do their trick in the wild too.
Impure gold, mixed with silver and copper, is found in the veins of minerals such as quartz, sometimes in such low concentrations as to be invisible. More obvious to the casual prospector are the highly enriched 'secondary grains' or nuggets found in river beds and soil. It is thought that these may be formed by weathering processes that either leach out the silver and copper metals, or wash the gold into solution so it can accumulate elsewhere.
Frank Reith of the Australian National University in Canberra and his colleagues have shown that microbes play a role too.
Geologists in the field have seen bacterial structures on gold grains before, and microbiologists in the laboratory have shown that many types of bacteria will deposit gold and other metals from solution. But the link between bacteria and gold deposits was tenuous. Now Reith and his team have bridged the divide.
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