BIOMAGNETIC AS A PROXY FOR ANCIENT LIFE

Magnetotactic bacteria have been considered for possible proxies of ancient life due to their ability to synthesize magnetite with distinct characteristics through biologically controlled mineralization. The organism’s cells lyse when they die and release magnetosome crystals into the environment, creating what are referred to as magnetofossils, which have been recovered from soils, freshwater and deep-sea sediments, and even Mars. The discoveries of magnetofossils in Martian samples, such as the 1996 ALH84001 meteorite, has led to controversy of whether they indicate life on Mars or are created through abiotic processes. Skeptics believe that some “fossils” result from human error during sample preparation and analysis, or that traces of possible life, such as organic molecules or carbon globules, were formed through nonbiological processes, but the evidence of magnetite continues to prove strong evidence, even for skeptics. If magnetite is found in a chain formation, similar to that which forms in the magnetosome, then it would be evident of past magnetotactic bacteria. While controversial, magnetofossils are possible proxies of ancient life and can be identified through the distinct characteristics of the various biogenic magnetite crystals.