scholarly journals Origin of Life’s Building Blocks in Carbon- and Nitrogen-Rich Surface Hydrothermal Vents

Life ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 12 ◽  
Author(s):  
Paul Rimmer ◽  
Oliver Shorttle
Keyword(s):  
Hydrogen Cyanide ◽  
Hydrothermal Vents ◽  
Prebiotic Chemistry ◽  
Organometallic Compounds ◽  
Building Blocks ◽  
Hydrothermal Systems ◽  
Subsurface Water ◽  
Geochemical Environment ◽  
Carbon And Nitrogen ◽  
Submarine Hydrothermal Systems

There are two dominant and contrasting classes of origin of life scenarios: those predicting that life emerged in submarine hydrothermal systems, where chemical disequilibrium can provide an energy source for nascent life; and those predicting that life emerged within subaerial environments, where UV catalysis of reactions may occur to form the building blocks of life. Here, we describe a prebiotically plausible environment that draws on the strengths of both scenarios: surface hydrothermal vents. We show how key feedstock molecules for prebiotic chemistry can be produced in abundance in shallow and surficial hydrothermal systems. We calculate the chemistry of volcanic gases feeding these vents over a range of pressures and basalt C/N/O contents. If ultra-reducing carbon-rich nitrogen-rich gases interact with subsurface water at a volcanic vent they result in 10 − 3 – 1 M concentrations of diacetylene (C4H2), acetylene (C2H2), cyanoacetylene (HC3N), hydrogen cyanide (HCN), bisulfite (likely in the form of salts containing HSO3−), hydrogen sulfide (HS−) and soluble iron in vent water. One key feedstock molecule, cyanamide (CH2N2), is not formed in significant quantities within this scenario, suggesting that it may need to be delivered exogenously, or formed from hydrogen cyanide either via organometallic compounds, or by some as yet-unknown chemical synthesis. Given the likely ubiquity of surface hydrothermal vents on young, hot, terrestrial planets, these results identify a prebiotically plausible local geochemical environment, which is also amenable to future lab-based simulation.

scholarly journals Prebiotic experiments simulating hydrothermal vents: Influence of olivine in the decomposition of simple carboxylic acids

2021 ◽  
Vol 73 (3) ◽  
pp. A291220
Author(s):  
Lucía A. González-López ◽  
María Colín-García ◽  
Adriana Meléndez-López ◽  
Jorge Cruz-Castañeda ◽  
Alicia Negrón-Mendoza
Keyword(s):  
Acetic Acid ◽  
Organic Acids ◽  
Carboxylic Acids ◽  
Hydrothermal Vents ◽  
Prebiotic Chemistry ◽  
Hydrothermal Systems ◽  
Early Earth ◽  
Prebiotic Chemical ◽  
Hydrothermal Environments

Hydrothermal systems have been proposed as keen environments on the early Earth where chemical evolution processes could have occurred. The presence of minerals and a continuous energy flux stand out among the most remarkable conditions in such environments. In this research the decomposition of two organic acids was studied. Ionizing radiation and thermal energy were the sources selected for decomposition tests, as both are naturally present on hydrothermal systems and probably, they were present on early Earth. Radiation could come from unstable elements in minerals, and heat is the most abundant energy source in hydrothermal systems. As minerals play a key role in prebiotic chemistry experiments and are an essential component on hydrothermal environments, the role of olivine in decomposition was tested. Results indicate that both organic acids highly decomposed when irradiated or heated. Radiation is more efficient than heating in decomposing the carboxylic acids and forming other carboxylic acids. Interestingly, the occurrence of olivine affects decomposition on both heated and irradiated samples, as both the rate of decomposition, and the amount and type of products vary compared with experiments without the mineral. The formation of other carboxylic acids was followed in all samples. Succinic, tricarballilic, citric and carboxisuccinic acids were detected in radiolysis experiments of acetic acid. The radiolysis of formic acid produced oxalic and tartronic. The heating of acetic acid solutions formed succinic, tricarballilic, citric and carboxisuccinic acids. However, the heating of formic acids only generated oxalic acid. The presence of olivine affected the amount and type of carboxylic acids formed in radiation and heating experiments. Natural hydrothermal systems are complex environments and many variables are present in them. Our results reinforce the idea that a combination of variables is necessary to better simulate these environments in prebiotic chemistry experiments. All variables could have affected the prebiotic chemical reactions; and hence, the role of hydrothermal systems in prebiotic chemistry could be much more complex that thought.

scholarly journals Determining the origin of the building blocks of the Ice Giants based on analogue measurements from comets

2019 ◽  
Vol 491 (1) ◽  
pp. 488-494 ◽  
Author(s):  
K E Mandt ◽  
O Mousis ◽  
S Treat
Keyword(s):  
Noble Gas ◽  
Giant Planet ◽  
Solid Material ◽  
Building Blocks ◽  
Atmospheric Composition ◽  
Isotopic Ratios ◽  
Carbon And Nitrogen ◽  
Formation Conditions ◽  
Comet 67P

ABSTRACT The abundances of the heavy elements and isotopic ratios in the present atmospheres of the giant planets can be used to trace the composition of volatiles that were present in the icy solid material that contributed to their formation. The first definitive measurements of noble gas abundances and isotope ratios at comet 67P/Churyumov–Gerasimenko (67P/C–G) were recently published by Marty et al. (2017) and Rubin et al. (2018, 2019). The implications of these abundances for the formation conditions of the 67P/C–G building blocks were then evaluated by Mousis et al. (2018a). We add here an analysis of the implications of these results for understanding the formation conditions of the building blocks of the Ice Giants and discuss how future measurements of Ice Giant atmospheric composition can be interpreted. We first evaluate the best approach for comparing comet observations with giant planet composition, and then determine what would be the current composition of the Ice Giant atmospheres based on four potential sources for their building blocks. We provide four scenarios for the origin of the Ice Giants building blocks based on four primary constraints for building block composition: (1) the bulk abundance of carbon relative to nitrogen, (2) noble gas abundances relative to carbon and nitrogen, (3) abundance ratios Kr/Ar and Xe/Ar, and (4) Xe isotopic ratios. In situ measurements of these quantities by a Galileo-like entry probe in the atmosphere(s) of Uranus and/or Neptune should place important constraints on the formation conditions of the Ice Giants.

Near-Bottom Magnetic Signatures of Submarine Hydrothermal Systems at Marsili and Palinuro Volcanoes, Southern Tyrrhenian Sea, Italy

2014 ◽  
Vol 109 (8) ◽  
pp. 2119-2128 ◽  
Author(s):  
F. Caratori Tontini ◽  
G. Bortoluzzi ◽  
C. Carmisciano ◽  
L. Cocchi ◽  
C. E. J. de Ronde ◽  
...  
Keyword(s):  
Hydrothermal Systems ◽  
Tyrrhenian Sea ◽  
Magnetic Signatures ◽  
Submarine Hydrothermal Systems ◽  
Southern Tyrrhenian Sea

Regulation of assimilate partitioning in leaves

2000 ◽  
Vol 27 (6) ◽  
pp. 507 ◽  
Author(s):  
Charlotte E. Lewis ◽  
Graham Noctor ◽  
David Causton ◽  
Christine H. Foyer
Keyword(s):  
Carbon Fixation ◽  
Starch Synthesis ◽  
Co2 Concentration ◽  
Building Blocks ◽  
Energy Budgets ◽  
Assimilate Partitioning ◽  
Fixed Carbon ◽  
Carbon And Nitrogen ◽  
Cellular Energy ◽  
Photosynthetic Carbon

Concepts of the regulation of assimilate partitioning in leaves frequently consider only the allocation of carbon between sucrose and starch synthesis, storage and export. While carbohydrate metabolism accounts for a large proportion of assimilated carbon, such analyses provide only a restricted view of carbon metabolism and partitioning in leaf cells since photosynthetic carbon fixation provides precursors for all other biosynthetic pathways in the plant. Most of these precursors are required for biosynthesis of amino acids that form the building blocks for many compounds in plants. We have used leaf carbon : nitrogen ratios to calculate the allocation of photosynthetic electrons to the assimilation of nitrogen necessary for amino acid formation, and conclude that this allocation is variable but may be higher than values often quoted in the literature. Respiration is a significant fate of fixed carbon. In addition to supplying biosynthetic precursors, respiration is required for energy production and may also act, in both light and dark, to balance cellular energy budgets. We have used growth CO2 concentration and irradiance to modify source activity in Lolium temulentum in order to explore the interactions between photosynthetic carbon and nitrogen assimilation, assimilate production, respiration and export. It is demonstrated that there is a robust correlation between source activity and foliar respiration rates. Under some conditions concomitant increases in source activity and respiration may be necessary to support faster growth. In other conditions, increases in respiration appear to result from internal homeostatic mechanisms that may be candidate targets for increasing yield.

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