High concentrations of methane gas – in some cases approaching 1m times the normal level – have been found around the BP oil spill, raising fears it could create an oxygen-depleted “dead zone” where marine life cannot survive.
Dead zones are areas in the water where algae blooms as it feeds on nutrients in high concentrations of foreign matter, such as methane, in this case, or, more typically, the components of farmland fertiliser runoff into the water. The algae gorge, reproduce quickly and then, in turn, are eaten by bacteria in a process that depletes the immediate area of oxygen. Fish and other sea life cannot survive in these zones, leading scientists to call them “dead”.
That the spill could cause a dead zone in the Gulf would be yet another negative for the environment, already suffering from the destruction of marine nurseries and bird nesting grounds in the wetlands and projections of negative impacts on sea life along the Gulf Coast. The knock-on effect would be a pocket of the Gulf where fishermen would find no fish or other sea creatures to harvest.