Nitrogen Oxide Concentrations in Natural Waters on Early Earth
A key challenge in origins-of-life studies is estimating the abundances of species relevant to the chemical pathways proposed to have contributed to the emergence of life on early Earth. Dissolved nitrogen oxide anions (NO-[subscript x]), in particular nitrate (NO-[subscript 3]) and nitrite (NO-[sub...
| Main Authors: | , , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
American Geophysical Union (AGU)
2020
|
| Online Access: | https://hdl.handle.net/1721.1/124622 |
| _version_ | 1811093823719211008 |
|---|---|
| author | Ranjan, Sukrit Todd, Zoe R. Rimmer, Paul R. Sasselov, Dimitar D. Babbin, Andrew R. |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Ranjan, Sukrit Todd, Zoe R. Rimmer, Paul R. Sasselov, Dimitar D. Babbin, Andrew R. |
| author_sort | Ranjan, Sukrit |
| collection | MIT |
| description | A key challenge in origins-of-life studies is estimating the abundances of species relevant to the chemical pathways proposed to have contributed to the emergence of life on early Earth. Dissolved nitrogen oxide anions (NO-[subscript x]), in particular nitrate (NO-[subscript 3]) and nitrite (NO-[subscript 2]), have been invoked in diverse origins-of-life chemistry, from the oligomerization of RNA to the emergence of protometabolism. Recent work has calculated the supply of NO-[subscript x] from the prebiotic atmosphere to the ocean and reported steady state [NO-[subscript x] to be high across all plausible parameter space. These findings rest on the assumption that NO-[subscript x] is stable in natural waters unless processed at a hydrothermal vent. Here, we show that NO-[subscript x] is unstable in the reducing environment of early Earth. Sinks due to ultraviolet photolysis and reactions with reduced iron (Fe[superscript 2+]) suppress [NO-[subscript x]] by several orders of magnitude relative to past predictions. For pH = 6.5–8 and T = 0–50 °C, we find that it is most probable that [NO-[subscript x]] <1μM in the prebiotic ocean. On the other hand, prebiotic ponds with favorable drainage characteristics may have sustained [NO-[subscript x]] ≥1μM. As on modern Earth, most NO-[subscript x] on prebiotic Earth should have been present as NO-[subscript 3], due to its much greater stability. These findings inform the kind of prebiotic chemistries that would have been possible on early Earth. We discuss the implications for proposed prebiotic chemistries and highlight the need for further studies of NO-[subscript x] kinetics to reduce the considerable uncertainties in predicting [NO-[subscript x]] on early Earth. |
| first_indexed | 2024-09-23T15:51:16Z |
| format | Article |
| id | mit-1721.1/124622 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T15:51:16Z |
| publishDate | 2020 |
| publisher | American Geophysical Union (AGU) |
| record_format | dspace |
| spelling | mit-1721.1/1246222022-09-29T16:35:37Z Nitrogen Oxide Concentrations in Natural Waters on Early Earth Ranjan, Sukrit Todd, Zoe R. Rimmer, Paul R. Sasselov, Dimitar D. Babbin, Andrew R. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences A key challenge in origins-of-life studies is estimating the abundances of species relevant to the chemical pathways proposed to have contributed to the emergence of life on early Earth. Dissolved nitrogen oxide anions (NO-[subscript x]), in particular nitrate (NO-[subscript 3]) and nitrite (NO-[subscript 2]), have been invoked in diverse origins-of-life chemistry, from the oligomerization of RNA to the emergence of protometabolism. Recent work has calculated the supply of NO-[subscript x] from the prebiotic atmosphere to the ocean and reported steady state [NO-[subscript x] to be high across all plausible parameter space. These findings rest on the assumption that NO-[subscript x] is stable in natural waters unless processed at a hydrothermal vent. Here, we show that NO-[subscript x] is unstable in the reducing environment of early Earth. Sinks due to ultraviolet photolysis and reactions with reduced iron (Fe[superscript 2+]) suppress [NO-[subscript x]] by several orders of magnitude relative to past predictions. For pH = 6.5–8 and T = 0–50 °C, we find that it is most probable that [NO-[subscript x]] <1μM in the prebiotic ocean. On the other hand, prebiotic ponds with favorable drainage characteristics may have sustained [NO-[subscript x]] ≥1μM. As on modern Earth, most NO-[subscript x] on prebiotic Earth should have been present as NO-[subscript 3], due to its much greater stability. These findings inform the kind of prebiotic chemistries that would have been possible on early Earth. We discuss the implications for proposed prebiotic chemistries and highlight the need for further studies of NO-[subscript x] kinetics to reduce the considerable uncertainties in predicting [NO-[subscript x]] on early Earth. Simons Foundation (SCOL Grant 495062) 2020-04-14T15:33:15Z 2020-04-14T15:33:15Z 2019-04 2018-11 2020-04-03T18:36:32Z Article http://purl.org/eprint/type/JournalArticle 1525-2027 https://hdl.handle.net/1721.1/124622 Ranjan, Sukrit, et al. “Nitrogen Oxide Concentrations in Natural Waters on Early Earth.” Geochemistry, Geophysics, Geosystems 20, 4 (April 2019): 2021–39. © 2019 The Authors en http://dx.doi.org/10.1029/2018GC008082 Geochemistry, Geophysics, Geosystems Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf American Geophysical Union (AGU) American Geophysical Union (AGU) |
| spellingShingle | Ranjan, Sukrit Todd, Zoe R. Rimmer, Paul R. Sasselov, Dimitar D. Babbin, Andrew R. Nitrogen Oxide Concentrations in Natural Waters on Early Earth |
| title | Nitrogen Oxide Concentrations in Natural Waters on Early Earth |
| title_full | Nitrogen Oxide Concentrations in Natural Waters on Early Earth |
| title_fullStr | Nitrogen Oxide Concentrations in Natural Waters on Early Earth |
| title_full_unstemmed | Nitrogen Oxide Concentrations in Natural Waters on Early Earth |
| title_short | Nitrogen Oxide Concentrations in Natural Waters on Early Earth |
| title_sort | nitrogen oxide concentrations in natural waters on early earth |
| url | https://hdl.handle.net/1721.1/124622 |
| work_keys_str_mv | AT ranjansukrit nitrogenoxideconcentrationsinnaturalwatersonearlyearth AT toddzoer nitrogenoxideconcentrationsinnaturalwatersonearlyearth AT rimmerpaulr nitrogenoxideconcentrationsinnaturalwatersonearlyearth AT sasselovdimitard nitrogenoxideconcentrationsinnaturalwatersonearlyearth AT babbinandrewr nitrogenoxideconcentrationsinnaturalwatersonearlyearth |