Non-biotic synthesis of organic polymers on H 2S-rich sea-floor: a possible reaction in the origin of life

Abstract

In continuous observations of the anoxic, H 2S-rich floor of the brackish Lake Nakanoumi, ammonia alone was observed to decrease remarkably without a corresponding decrease of total nitrogen or increase of nitrite and nitrate. This newly observed phenomenon cannot be interpreted by conventional physical or biological reactions; it possibly suggests a new chemical synthesis of particulate amino acid on the anoxic lake floor in the presence of hydrogen sulphide. To understand the mechanisms of these results, we carried out some model experiments using hydrogen sulphide as a reagent. In these experiments, we found a new non-biotic synthesis of organic polymers containing amino acids from the reaction of hydrogen sulphide and a mixture of ammonium formate, formaldehyde and magnesium chloride in water at room temperature. This reaction is possibly based on the reduction and dehydration by hydrogen sulphide. This entirely new non-biotic synthesis is an important reaction to consider as the first stage of the origin of life.