Aquatic Ferrous Solutions of Prebiotic Mineral Salts as Strong UV Protectants and Possible Loci of Life Origin

Liposomes are lipid-bilayer vesicles that spontaneously self-assemble from fatty acids (or other amphiphiles) in water by encapsulating surrounding aqueous media. After British scientist Alec Bangham described this phenomenon in the early 1960s, they became a prominent participant in the hypotheses on life origin, particularly in the Lipid World model. A novel scenario of self-sustained Darwinian liposome evolution is based on ever-present natural phenomena of cyclic day/night solar UV radiation and gravitational submersion of liposomes in the Archean aqueous media. One of the assumptions of the hypothesis is the UV-shielding ability of the Archean waters that could protect the submerged liposomes from the damaging solar UV radiation. To corroborate the idea, we measured UV absorption in aquatic solutions of several ferrous mineral salts assumed to be present in Archean pools. Single-agent solutions of simple salts such as FeCl(2)—iron dichloride, FeCl(3)—iron trichoride, Fe(NO(3))(3)—ferric nitride, NH(4)Fe(SO(4))(2)—ferric ammonium sulfate, and (NH(4))(5)[Fe(C(6)H(4)O(7))(2)]—ferric ammonium citrate were tested. These direct measurements of UV light absorption supplement and reinforce the proposed hypothesis.