Giant living power cables let bacteria respire
Date: 24.9.2012
NewScientist 29.6. 2012 by Sara Reardon. IT IS the ultimate in subsea communications: bacteria living in sulphurous mud beneath the seabed respire by transforming themselves into long, insulating cables and shuttling electrons from one to another. This phenomenon has now been imaged for the first time, allowing us to see how some microbes pull off such a feat.
Some bacteria get energy by oxidising the hydrogen sulphide gas in the sediment on the ocean floor. Because there is no oxygen in the sediment to accept the electrons that are produced, bacteria such as Geobacter grow tiny filaments along which the electrons travel until they reach the oxygen in the seawater. This allows the respiration reaction to be completed.
To find out how other bacteria solve this problem, Lars Peter Nielsen of Aarhus University in Denmark and colleagues used an electron microscope to image electrically conducting Desulfobulbus bacteria in sediment samples. They found that individual bacteria, despite being only 3 to 4 micrometres long, are capable of organising themselves into giant power cables made up of several thousand bacteria. These cables can stretch to around 1 centimetre in length, connecting the deepest bacteria living in low-oxygen conditions with those in high-oxygen areas (see diagram)...
