Red Sea brine pools reveal anaerobic microbial life powered by metal oxidation

Near the bottom of the Red Sea, at a depth of nearly 1.8 kilometers, brine pools exist in conditions that seem inhospitable to most life forms. These hypersaline lakes, separated from the surrounding ocean by density and salt concentration, serve as a model for the early Earth, specifically the period before the Great Oxidation Event. A study led by Dr. Chakraborti and an international team of researchers found that microbial life thrives in these oxygen-poor, lightless environments by utilizing common metals as energy sources. The genetic analysis of these pools revealed a dense community of bacteria and archaea. Beneath the microbial mats on the pool floors, scientists detected anomalous concentrations of manganese, iron, molybdenum, and copper. In some locations, these metal levels were 100 times higher than those found on a typical seabed. The mechanism driving this ecosystem is chemical oxidation, a process defined by the transfer of electrons from one substance to another, rather than the aerobic oxidation familiar from combustion or rust. The researchers identified specific microbial groups, such as Nitrospira, capable of oxidizing manganese and iron to extract energy. Essentially, these organisms feed on the chemical transformation of metals, bypassing the need for sunlight or atmospheric oxygen.