High concentration of electric bacteria found in Australia

Sydney Morning Herald : Two years ago a species of bacteria was discovered in Denmark that had the unusual ability to grow centimeters-long insulated cables that conduct electricity. Now the bacteria have been found in the mouth of the Yarra River in Australia. The most surprising part of the discovery is the concentration of the bacteria. A footprint-sized patch of river sediment holds enough bacteria to produce 1–2 volts. According to Perran Cook of Monash University in Melbourne, the high concentration is due to different layers of water in the river. Salty water from the ocean forms the bottom layer, with freshwater above it. Because the freshwater prevents oxygen from reaching the saltwater layer, concentrations of hydrogen sulfide, the bacteria’s favored energy source, increase and settle into the sediment at the bottom of the river.