The Alkaline Solution to the Emergence of Life: Energy, Entropy and Early Evolution

Abstract

The Earth agglomerates and heats. Convection cells within the planetary interior expedite the cooling process. Volcanoes evolve steam, carbon dioxide, sulfur dioxide and pyrophosphate. An acidulous Hadean ocean condenses from the carbon dioxide atmosphere. Dusts and stratospheric sulfurous smogs absorb a proportion of the Sun's rays. The cooled ocean leaks into the stressed crust and also convects. High temperature acid springs, coupled to magmatic plumes and spreading centers, emit iron, manganese, zinc, cobalt and nickel ions to the ocean. Away from the spreading centers cooler alkaline spring waters emanate from the ocean floor. These bear hydrogen, formate, ammonia, hydrosulfide and minor methane thiol. The thermal potential begins to be dissipated but the chemical potential is dammed. The exhaling alkaline solutions are frustrated in their further attempt to mix thoroughly with their oceanic source by the spontaneous precipitation of biomorphic barriers of colloidal iron compounds and other minerals. It is here we surmise that organic molecules are synthesized, filtered, concentrated and adsorbed, while acetate and methane--separate products of the precursor to the reductive acetyl-coenzyme-A pathway-are exhaled as waste. Reactions in mineral compartments produce acetate, amino acids, and the components of nucleosides. Short peptides, condensed from the simple amino acids, sequester 'ready-made' iron sulfide clusters to form protoferredoxins, and also bind phosphates. Nucleotides are assembled from amino acids, simple phosphates carbon dioxide and ribose phosphate upon nanocrystalline mineral surfaces. The side chains of particular amino acids register to fitting nucleotide triplet clefts. Keyed in, the amino acids are polymerized, through acid-base catalysis, to alpha chains. Peptides, the tenuous outer-most filaments of the nanocrysts, continually peel away from bound RNA. The polymers are concentrated at cooler regions of the mineral compartments through thermophoresis. RNA is reproduced through a convective polymerase chain reaction operating between 40 and 100 degrees C. The coded peptides produce true ferredoxins, the ubiquitous proteins with the longest evolutionary pedigree. They take over the role of catalyst and electron transfer agent from the iron sulfides. Other iron-nickel sulfide clusters, sequestered now by cysteine residues as CO-dehydrogenase and acetyl-coenzyme-A synthase, promote further chemosynthesis and support the hatchery--the electrochemical reactor--from which they sprang. Reactions and interactions fall into step as further pathways are negotiated. This hydrothermal circuitry offers a continuous supply of material and chemical energy, as well as electricity and proticity at a potential appropriate for the onset of life in the dark, a rapidly emerging kinetic structure born to persist, evolve and generate entropy while the sun shines.

Quantifying drivers of chemical disequilibrium: theory and application to methane in the Earth's atmosphere

“…If we assume that the total amount of biomass stays roughly constant, we can combine Reactions (R1), (R2) and (R3) to give the net reaction Thus, life's net effect upon the atmosphere in terms of the methane-oxygen disequilibrium is to continually remove CO 2 and add O 2 and CH 4 (Russell, 2007). The rate at which this occurs can be determined by estimating the rate at which…”

Inorganic Polyphosphate Modulates TRPM8 Channels

“…Accordingly, some scholars have considered solar radiation to be the driving force of abiogenesis [5,85,[103][104][105][106][107][108][109][110][111][112]. Others have hypothesized that chemical or redox disequilibria at the sea-floor hydrothermal vents [113][114][115][116][117][118][119][120][121][122][123] or at the surface of sea-floor iron minerals [124][125][126][127][128][129][130] could have driven the emergence of the first organisms. As argued in more detail elsewhere [85], a direct analogy between primordial life and modern deep-sea biotopes is not possible, since the redox energy span of > 1 eV between the reduced compounds of hydrothermal fluids and the sea-dissolved oxygen became exploitable only after the ocean waters -only 2 Ga agowere saturated by oxygen, a by-product of cyanobacterial photosynthesis [101,131,132].…”

“…On the other hand, the equilibrium concentration of such ions in sea water is very low (see Table 1). This paradox is routinely resolved by invoking hydrothermal settings as potential cradles of life [113][114][115][116][117][118][119][120][121][122][123]177]. In such systems, which currently cluster around the mid-ocean ridges and deep-sea submerged volcanoes (seamounts) -where hot magma chambers occur near the seabed -water circulates down into the crust, becomes heated, and then rises up.…”

Fluid chemistry of the low temperature hyperalkaline hydrothermal system of Prony Bay (New Caledonia)

“…The highly reducing conditions of the serpentinizing environment allows the development of abiotic organic compounds (Lang et al, 2010) and hosts a large and specific community of microorganisms (Brazelton et al, 2010(Brazelton et al, , 2006. Such hyperalkaline hydrothermal systems may have been numerous on the early Earth, as well as on the Martian surface (Szponar et al, 2012) and may have also been the locus of the emergence of earliest forms of life (Muntener, 2010;Russell, 2007;Russell et al, 2010).…”