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Publications page.



Publications by David Catling

SCHOLARLY BOOKS:
Atmospheric Evolution1) For graduate students and researchers:

D. C. Catling and J. F. Kasting (2017), Atmospheric Evolution on Inhabited and Lifeless Worlds, Cambridge University Press.



Related guest blog @Cambridge University Press:
"Something in the air: The search for life on distant planets"

A small list of errata for the book is available.




Astrobiology VSI book cover2) For the educated layperson:

David C. Catling (2013) Astrobiology: A Very Short Introduction, Oxford University Press.
(Also published in Swedish (Astrobiologi) by Fri Tanke and in Turkish (Astrobiyoloji) by Metis Yayinlari. Chinese version with updates coming in 2025 from Yilin Press, Nanjing).

Reviews of the book.  Numerous reviews can be found on websites such as goodreads.
 
 Questions & Answers about astrobiology & the book.

Guest blog @Oxford University Press: "Astrobiology: Pouring Cold Asteroid Water on Aristotle"

Reading Guide: Questions for Thought and Discussion for Astrobiology: A Very Short Introduction.


3) For the person-in-the-street: (currently being written and coming soon!):

David C. Catling, Revisiting the Voyage that Changed the World (working title)
This book is about revisiting the landfalls of Charles Darwin's nearly 5-year voyage around the world (1831-1836), which he eloquently describes in The Voyage of the Beagle (1839). Following Darwin's footsteps has been my hobby for almost 20 years, and Darwin himself has been a great guide through vivid descriptions of biology, anthropology, and geology in his 1839 travelogue. Darwin traveled as a young man only in his twenties, and his innate brilliance at observing the world continues to amaze me. The book is a personal view of what has changed between then and now in the places that Darwin visited from scientific, human, and environmental perspectives.

Articles listed by most cited via David Catling Google Scholar Page
(Also David Catling ORCID page, but it doesn't automatically update like google-scholar).

 Articles/Book Chapters:

2025    
192. D. C. Catling, J. Krissansen-Totton, T. D. Robinson (2024). Potential technosignature from anomalously low deuterium/hydrogen (D/H) in planetary water depleted by nuclear fusion technology, Astrophysical  Journal, in press.

191. S. Haas, B.M. Tutolo, D. C. Catling (2024) A phosphorus budget of soda lakes finds major biological sinks, implying abundant phosphate-availability at the origin of life, Geochimica Cosmochimica Acta, in revision.

 190. S. Viscardy, D. C. Catling, K. J. Zahnle (2024). Questioning the reliability of methane detections on Mars by the Curiosity Rover, Journal of Geophysical Research- Planets, revised paper with Editor.

189. T. Kizovski et al. (incl. D. C. Catling) (2024) Fe-phosphates in Jezero Crater: Chemical, Structural, and Spectral Evidence for an Ancient Habitable Environment on Mars, Nature Communicationsin, in revision.

188. A. Bravenec, D. C. Catling (2024) Empirical freezing of oxychlorine salts constrains properties of potentially habitable brines in martian ice, Planetary Science Journal, in revision.

187. Y.-C. Chan, L. Jaeglé, P. Campuzano-Jost, D. C. Catling, V. I. Furdui, W. A. Jackson, J. L. Jimenez, D. Kim, B. Alexander (2024) Global model of atmospheric chlorate on Earth, Journal of Geophysical Research - Atmospheres, revised paper with editor.

186. F. Klenner (incl. D. C. Catling) (2024) Supercooling, glass formation and mineral assemblages in freshly frozen ice grains from Enceladus, submitted to Planetary Science Journal, in revision.

185. M. W. M. Jones, D. T. Flannery, J. A. Hurowitz, M. T. Tice, C. E. Schrank, A. C. Allwood, N. J. Tosca, D. C. Catling et al. (2024) In-situ crystallographic mapping constrains sulfate deposition and timing in Jezero crater, Mars, submitted.

184. A. Shumway, T. Kizovski, D. C. Catling et al. (2024). X-ray spectroscopy with the PIXL instrument reveals the composition and alteration history of regolith on the delta/fan front in Jezero Crater, Mars, Journal of Geophysical Research - Planets, submitted.

183. L. Fifer, D. C. Catling, R. Hamp, F. Klenner, J. Toner. (2024) Enceladus as a chemically evolving ocean world due to long-term plume eruption and gas loss, drafting.

182. D. C. Catling + General models and principles for global redox controls on atmospheric O2 and CH4, over Earth history, in prep.

181. D. C. Catling, C. B. Leovy, S. E. Wood, M. D. Day. Does the Vastitas Borealis Formation, Mars, contain oceanic or volcanic  deposits?:  Subsurface sampling using small craters, in prep.

2024
180. N. F. Wogan, D. C. Catling, K. J. Zahnle (2024). Timing and likelihood of an origin of life derived from post-impact highly reducing atmospheres, Astrobiology 24, 881-891. https://doi.org/10.1089/ast.2023.0128 Open Access.

179. T. B. Thomas, D. C. Catling (2024) Three-stage formation of cap carbonates after Marinoan Snowball glaciation consistent with depositional timescales and geochemistry, Nature Communications, 15, 7055. https://doi.org/10.1038/s41467-024-51412-8
Open Access.

178. Z. R. Cohen, D. Ding, L. Zhou, S. DasGupta, S. Haas, K. Sinclair, Z. R. Todd, R. A. Black, J. W. Szostak, D. C. Catling (2024). Natural soda lakes provide compatible conditions for RNA and membrane function that could have enabled the origin of life, PNAS Nexus 3, pgae084  https://doi.org/10.1093/pnasnexus/pgae084 Open Access.

177. S. Haas, K. P. Sinclair, D. C. Catling (2024) Biogeochemical explanations for the world’s most phosphate-rich lake, an origin-of-life analog, Communications Earth & Environment, 5, 28. https://doi.org/10.1038/s43247-023-01192-8 Open Access.
University of Washington news: Shallow soda lakes show promise as cradles of life on Earth ;
Canadian Broadcasting Corporation (CBC) news with video: A shallow, salty lake in B.C. could point to origins of life on Earth

176. A. V. Young, T. D. Robinson, T. D., J. Krissansen-Totton, E. W. Schwieterman, N. F. Wogan, M. J. Way, L. E. Sohl, G. N. Arney, C. T. Reinhard, M. R. Line, D. C. Catling, and J. D. Windsor, 2024, Inferring chemical disequilibrium biosignatures for Proterozoic Earth-like exoplanets: Nature Astronomy, 8, 101-110. https://doi.org/10.1038/s41550-023-02145-z Open Access.

175. Z. R. Todd, N. Wogan, D. C. Catling (2024). Favorable environments for the formation of ferrocyanide, a potentially critical reagent for origins of life, ACS Earth & Space Chemistry 8, 221-229. https://doi.org/10.1021/acsearthspacechem.3c00213 Open Access.

174.  Z. R. Cohen, Z. R. Todd, L. Maibaum, D. C. Catling, R. A. Black (2024). Stabilization of prebiotic vesicles by peptides depends on sequence and chirality, Langmuir  40, 8791-8990. https://doi.org/10.1021/acs.langmuir.4c00150.

173. Z. R. Todd, G. G. Lozano, C. L. Kufner, S. Ranjan, D. C. Catling, D. D. Sasselov (2024). Ultraviolet transmission in prebiotic environments on the early Earth, Astrobiology 24, 559-569, doi:10.1089/ast.2023.0077. Open Access.

172. P-C. Lin and D. C. Catling (2024). The rare earth element distribution in marine carbonates as a potential proxy for seawater pH on early Earth, American Journal of Science 324, 10. https://doi.org/10.2475/001c.118215.  Open Access.

171. T. Bosak et al (incl. D. C. Catling) (2024) Astrobiological potential of rocks acquired by the Perseverance rover at a sedimentary fan front in Jezero crater, Mars, AGU Advances,  5, e2024AV001241 https://doi.org/10.1029/2024AV001241 . Open Access.

170. H. Kalucha, A. Broz, N. Randazzo, J. Aramendia, J.M. Madariaga, B. Garczynski, N. Lanza, L. Mandon, T. Fouchet, D. C. Catling et al. (2024) Probable concretions observed in the Shenandoah Formation of Jezero Crater, Mars and comparison with terrestrial analogs, Journal of Geophysical Research-Planets 129, e2023JE008138. https://doi.org/10.1029/2023JE008138 .


2023
169. Wogan, N., Catling, D. C., Zahnle, K. J., R. Lupu (2023) Origin of life molecules in the atmosphere after big impacts on the early Earth,  Planetary Science Journal, 4, 169. Open Access.

168. J. A. Hurowitz, D. C. Catling, W. W. Fischer (2023) High carbonate alkalinity lakes and their potential role in an origin of life beyond Earth, Elements 19, 37-44.
[PDF]. Open Access.

167. A. Shumway, J. D. Toner, D. C. Catling (2023) Regolith inhibits salt and ice crystallization in Mg(ClO4)2 brine, implying more persistent and potentially habitable brines on Mars, Planetary Science Journal 4, 143. Open Access.

166. Y.-C. Chan, L. Jaeglé, P. Campuzano-Jost, D. C. Catling, et al. (2023). Gas-phase stratospheric chemistry alone cannot explain observations of perchlorate on Earth, Geophysical Research Letters 50, e2023GL102745. [PDF]. Open Access.

165. A. D. Bravenec & D. C. Catling (2023) Effect of concentration, cooling, and warming rates on glass transition temperatures for NaClO4, Ca(ClO4)2, and Mg(ClO4)2 brines with relevance for Mars and other cold bodies, ACS Earth & Space Chemistry. Open Access. https://doi.org/10.1021/acsearthspacechem.3c00090
Glass forming abilityGraphic abstract, showing:
Perchlorate salts have an unusual ability to easily form glasses (i.e., amorphous or non-crystalline solids) compared to other substances in nature. Most substances require very rapid cooling to form glass but perchlorate solutions can be cooled relatively slowly and still form glasses. Glass might be a medium in which microbes are preserved if they exist on other celestial bodies.


2022
164. Z. R. Cohen, Z. R. Todd, N. Wogan, R. A. Black, S. L. Keller, D. C. Catling (2022) Plausible sources of membrane-forming fatty acids on the early Earth: A review of the literature and an estimation of amounts, ACS Earth & Space Chemistry, https://doi.org/10.1021/acsearthspacechem.2c00168 Open Access.
Graphic abstract, Cohen+ (2022)
Graphic abstract (left): We review the origin of fatty acid molecules that were big enough and so able to spontaneously form spherical shells in water, i.e., the first cell membranes in the origin of life on Earth.



163. Y. Liu et al. (incl. D. C. Catling) (2022). An olivine cumulate outcrop on the floor of Jezero crater, Mars, Science 377, 1513-1519. https://dx.doi.org/10.1126/science.abo2756
 162. N. Wogan, D. C. Catling, K. J. Zahnle, M. W. Claire (2022) Rapid timescale for an oxic transition during the Great Oxidation Event and the instability of low atmospheric O2, Proceedings of the National Academy of Sciences USA 119, e2205618119.  https://doi.org/10.1073/pnas.2205618119 Open Access. [PDF]

161. L. M. Fifer, D. C. Catling, J. D. Toner (2022) Chemical fractionation modeling of plumes indicates a gas-rich, moderately alkaline Enceladus ocean, Planetary Science Journal 3, 191.  Open Access [PDF]. https://doi.org/10.3847/PSJ/ac7a9f
Saturn's moon, Enceladus, has plumes coming out of its south polar region. We use Cassini spacecraft data and simulations of how water and gases form the plumes to estimate a pH of about 8 to 9, other aqueous chemistry, and habitability of the ocean beneath the icy surface of Enceladus.

160. J. Hao, C. Glein, F. Huang, N. Yee, D. C. Catling, F. Postberg, J. K. Hillier, R. M. Hazen (2022), Abundant phosphorus expected for possible life in Enceladus's ocean, Proceedings of the National Academy of Sciences USA 119, e2201388119, doi:10.1073/pnas.2201388119 Open Access. [PDF].

 159. Z. R. Cohen, C. E. Cornell, D. C. Catling, R. A. Black, S. L. Keller (2022) Prebiotic protocell membranes retain encapsulated contents during flocculation, and phospholipids preserve encapsulation during dehydration, Langmuir 38, 3, 1304–1310, doi: 10.1021/acs.langmuir.1c03296.
During the origin of life, primitive cell membranes would have encapsulated useful molecules, e.g., an RNA genome. Evaporative lakes are useful places for prebiotic synthesis because they concentrate reactants during drying, which drives reactions without enzymes. Here we investigate whether a protocell membrane can keep its encapsulated contents during drying episodes or whether the contents leak out.

158. J. D. Toner, R. S. Sletten, L. Liu, D. C. Catling, D. Ming, A. Mushkin, P.-C. Lin (2022) Wet streaks in the McMurdo Dry Valleys, Antarctica: Implications for Recurring Slope Lineae on Mars, Earth & Planetary Science Letters, 589, 117582  https://doi.org/10.1016/j.epsl.2022.117582

157. Z. R. Todd, G. G. Lozano, C. L. Kufner, D. D. Sasselov, D. C. Catling, Ferrocyanide survival under near ultraviolet (300-400 nm) irradiation on early Earth. Geochimica Cosmochimica Acta, 335, 1-10 (2022). https://doi.org/10.1016/j.gca.2022.08.012

156.  Z. R. Cohen, Z. R. Todd, D. C. Catling, R. A. Black, S. L. Keller (2022) Prebiotic vesicles retain solutes and grow by micelle addition after brief cooling below the membrane melting temperature, Langmuir 38, 13407-13413. https://doi.org/10.1021/acs.langmuir.2c01842

155.  Z. R. Todd, Z. R. Cohen, D. C. Catling , S. L. Keller, R. A. Black (2022) Growth of prebiotically plausible fatty acid vesicles proceeds in the presence of prebiotic amino acids, dipeptides, sugars, and nucleic acid components, Langmuir, https://doi.org/10.1021/acs.langmuir.2c02118 . Open Access.
Todd+ 2022 graphic abstract
Graphic abstract, showing:
  • lipid bilayer vesicles (protocell membranes)
  • micelles (in blue), which are are single layer globules of lipids with polar heads on the outside
  • how vesicles grow by addition of the micelles while other molecules may bind to the vesicles.


2021
154.  O. R. Lehmer, D. C. Catling, M. N. Parenteau, N. Y. Kiang, T. M. Hoehler, The peak absorbance wavelength of photosynthetic pigments around other stars from spectral
optimization, Frontiers in Astronomy & Space Sciences 8, 689441. doi: 10.3389/fspas.2021.689441, 2021. Open Access [PDF]
Vegetation causes a steep increase in reflectance over red to near-infrared wavelengths, which is seen on the Earth from space and known as "the red edge”. Using physical theory, we compute how photosynthesis would adapt on planets around other stars with different spectra and we predict the wavelengths of red edge analogs. This might be a means to detect life on exoplanets in the future.

153. S. F. Sholes, Z. I. Dickeson,  D. Montgomery, D. C. Catling, Where are Mars' hypothesized ocean shorelines? Large lateral and topographic offsets between different versions of paleoshoreline maps. Journal of Geophysical Research-Planets, 126, e2020JE006486. https://doi.org/10.1029/2020JE006486 (Preprint version: https://doi.org/10.1002/essoar.10502868.1)
We compare maps of putative ancient shorelines on Mars and find that their  locations are  inconsistent. Sometimes lateral offsets between what are meant to be the same shoreline locally exceed 1000 km. Different researchers have mapped the "same" shoreline in very different places based on surface properties that are not unique to coastlines, e.g., albedo contrasts. So, we question the robustness of putative shorelines as meaningful evidence for ancient martian oceans.

152. J.  Krissansen-Totton, M. A. Kipp & D. C. Catling (2021) Carbon cycle inverse modeling suggests large changes in fractional organic burial are consistent with the carbon isotope record and may have contributed to the rise of oxygen, Geobiology 2021;00:1–22. doi: 10.1111/gbi.12440  Open Access [PDF]

151.  M. Kipp, J. Krissansen-Totton, D. C. Catling (2021) High burial efficiency is required to explain mass balance in Earth’s early carbon cycle, Global Biogeochemical Cycles 35, e2020GB006707. doi: 10.1029/2020GB006707.

150. A. Mendez et al. (incl. D. C. Catling) (2021) Habitability models for astrobiology, Astrobiology 21, 1017-1027. https://doi.org/10.1089/ast.2020.2342

2020
149. O. R. Lehmer, D .C. Catling, J. Krissansen-Totton (2020) Carbonate-silicate cycle predictions of Earth-like planetary climates and testing the habitable zone concept, Nature Communications 11, 6153.  [PDF]. Open Access

 148. J. A. Kegerreis, V. R. Eke, D. C. Catling, R. J. Massey, L. F. A. Teodoro, K. J. Zahnle (2020) Atmospheric erosion by giant impacts onto terrestrial planets: A scaling law for any speed, angle, mass, and density. Astrophys.  J. Lett. 901, L31, 2020. https://arxiv.org/abs/2007.04321.

147.  N. Wogan, J. Krissansen-Totton, D. C. Catling. Abundant atmospheric methane from volcanism on terrestrial planets is unlikely and strengthens the case for methane as a biosignature, Planetary Science Journal, 1, 58, 2020. [PDF]. Open Access. https://doi.org/10.3847/PSJ/abb99e

146. S. Kadoya, D. C. Catling, R. W. Nicklas, I. Puchtel, A. D. Anbar. Mantle data imply a decline of oxidizable volcanic gases could have triggered the Great Oxidation, Nature Communications 11, 2774, 2020. [PDF]. https://doi.org/10.1038/s41467-020-16493-1 Open Access.

145. D. C. Catling & K. J. Zahnle. The Archean Atmosphere, Science Advances 6, eaax1420, 2020, doi: 10.1126/sciadv.aax1420. [PDF]. Open Access.
The Archean eon  from 4 billion to 2.5 billion years ago is one-third of the history of the Earth. We review what the Archean atmosphere was made of and the climates of the Archean.

144. O. R. Lehmer, D. C. Catling, R. Buick, D. E. Brownlee, S. Newport. Atmospheric CO2 levels from 2.7 billion years ago inferred from micrometeorite oxidation, Science Advances 6, eaay4644 2020. [PDF]. Open Access. https://advances.sciencemag.org/content/6/4/eaay4644
Here's a pretty cool little youtube animation of an example computer simulation of micrometeorite atmospheric entry used in this work.
We assess atmospheric oxidation of 2.7 billion-year-old iron-nickel (I-type) micrometeorites to argue that high levels of CO2 caused their oxidation. We calculate the physics of micrometeorites entering the atmosphere. Using heating and kinetic oxidation calculations, we estimate that atmospheric CO2 concentrations were high, possibly more than about 70% at the time.

143. K. Zahnle, R. Lupu, D. C. Catling, N. Wogan, Creation and evolution of impact-generated reduced atmospheres of early Earth, Planetary Science Journal 1, 11, 2020. Open Access. [PDF]  https://doi.org/10.3847/PSJ/ab7e2c
We discuss how hydrogen- and methane-rich atmospheres, chemically resembling the atmosphere of Titan, would have been produced on the early Earth as a result of impacts. The iron in the core of large impactors reacts with seawater to generate hydrogen, which can react with carbon dioxide to make methane. Such atmospheres would have made abundant organic molecules suitable for an origin of life.

142. J. Krissansen-Totton & D. C. Catling, A coupled carbon-silicon cycle model over Earth history: Reverse weathering as a possible explanation of a warm mid-Proterozoic climate, Earth & Planetary Science Letters, 537, 116181, 2020. doi: 10.1016/j.epsl.2020.116181 [PDF]. Open Access.
We present the first self-consistent, coupled carbon-silica cycle simulations over Earth history to investigate reverse weathering, i.e., when cations enter clay minerals instead of carbonates, which leaves CO2 in the air and allows warmer climates. We find that reverse weathering may have contributed to a prolonged warm climate in the Proterozoic eon, but large uncertainties on parameters in reverse weathering calculations mean that we cannot be sure. More data are needed to reduce the uncertainties about the kinetics of reverse weathering.

141. N. Wogan & D. C. Catling. When is chemical disequilibrium in Earth-like planetary atmospheres a biosignature versus an anti-biosignature? Disequilibria from dead to living worlds. Astrophysical Journal 892, 197. https://doi.org/10.3847/1538-4357/ab7b81 ;
https://arxiv.org/abs/1911.06852
We show that chemical disequilibrium in an Earth-like exoplanet atmosphere (remotely detectable with telescopes) can indicate life or no life, depending on context. Build up of volcanic gases in the atmosphere of an uninhabited world would be an anti-biosignature, showing that there are no microbes using free energy from reacting those gases for metabolism. But on a planet with a biosphere, disequilibrium from a mixture of biogenic gases, which would otherwise disappear from photochemical reactions, is a biosignature of continuous gas fluxes from a biosphere. Determining if life is present or not is linked to activation energies. A disequilibrium mixture of gases  that reacts with low activation energy can easily be eaten, and so is an anti-biosignature, showing no life present. On the other hand, high activation energy to react a disequilibrium mixture of gases means that microbes can't access the available free energy, which applies to a mixture of biogenic gases in the atmosphere of an inhabited world (e.g., the modern Earth).

140.  S. Kadoya, J. Krissansen-Totton & D. C. Catling, Probable cold and alkaline surface environment of the Hadean Earth caused by impact ejecta weathering, Geochemistry, Geophysics, Geosystems 21, e2019GC008734, 2020. Open Access. [PDF] https://doi.org/10.1029/2019GC008734

139.  J. D. Toner & D. C. Catling, A carbonate-rich lake solution to the phosphate problem of the origin of life, Proceedings of the National Academy of Sciences USA 117, 883-888, 2020, DOI: 10.1073/pnas.1916109117.  Open Access. [PDF].
Phosphorus is essential for biology and used in genetic molecules, energy molecules, and cell membranes. In nature, phosphate (PO43-) gets locked up in the mineral apatite (= calcium phosphate), which is very poorly soluble. Consequently, the concentration of phosphate in natural waters is about a million times less than that needed for chemical reactions demonstrated in the lab that could have incorporated phosphate into biomolecules for the origin of life. This long-standing dilemma is called "the phosphate problem" of the origin of life. We answer this conundrum by showing that carbonate-rich, closed-basin lakes remove calcium as calcium carbonate and allow dissolved phosphate to build up. Evaporation can concentrate phosphate to the high levels needed for prebiotic chemistry. Problem solved.

138. E. Gillen, P. B. Rimmer, D. C. Catling. Statistical analysis of Curiosity data shows no evidence for a strong seasonal cycle of methane on Mars, Icarus 336, 113407, 2020.  [PDF]. Open Access.  https://doi.org/10.1016/j.icarus.2019.113407
In 2018, Science reported that data from NASA's Curiosity Rover showed "strong seasonal variation" of tiny amounts of methane in the martian atmosphere, which led to lots of speculation about mechanisms for how this would happen. We show that statistical analysis of the data does not favor seasonal variation over non-periodic random variation or a large spread of other periods. The data and their error bars are far  too sparse to demonstrate seasonal variation with significant probability. In fact, the variation in the data is ~10 times more likely to be stochastic (i.e., have a strong random component) than be seasonal.

137.  S. Kadoya, D. C. Catling, R. W. Nicklas, I. Puchtel, A. D. Anbar. Mantle cooling causes more reducing volcanic gases and gradual reduction of the atmosphere, Geochemical Perspective Letters, 13, 25-20 2020. Open Access. [PDF]  doi: 10.7185/geochemlet.2009

136. E. A. Goosmann, C. Luskin,  D. C. Catling, R. Buick, N. Nhleko. Vesicular paleobarometry in the Pongola Supergroup: A cautionary note and guidelines for future studies, South African Journal of Geology, https://doi.org/10.25131/sajg.123.0005, 2020. [PDF] .
2019
135. S. Kadoya, & D. C. Catling. Constraints on hydrogen levels in the Archean atmosphere based on detrital magnetite, Geochimica Cosmochimica Acta, 262, 207-219, 2019. [PDF]. https://doi.org/10.1016/j.gca.2019.07.041
We show that atmospheric hydrogen (H2) levels 3 billion years ago were less than 0.01 bar partial pressure because grains of magnetite (Fe3O4) found in river beds of that age would dissolve under higher H2 levels. Some literature had speculated that H2 might have been a significant greenhouse gas on the Earth at this time, but the levels we infer are too low. Instead, the H2 levels are consistent with H2 being eaten by microbial life and turned into methane (CH4).

134. J. D. Toner & D. C. Catling, Alkaline lake settings for concentrated prebiotic cyanide and the origin of life, Geochimica Cosmochimica Acta, 260, 124-132, https://doi.org/10.1016/j.gca.2019.06.031, Open Access. [PDF]. 2019.
With new experimental data incorporated into aqueous chemistry calculations, we show that closed-based, carbonate-rich lakes on the early Earth would concentrate and precipitate hydrated sodium ferrocyanide, providing a cyanide stockpile for subsequent prebiotic chemistry. Cyanide is a key ingredient in organic synthesis of prebiotic biomolecules because it is a strong nucleophile (i.e., a compound that donates electron pairs to build carbon-carbon chains and C-N groups), which has been shown experimentally to make amino acids, nucleotides, and lipid precursors (e.g., reviewed by Islam & Powner (2017)).

 133. K. J. Zahnle, M. Gacesa, D. C. Catling, Strange messenger: A new history of hydrogen on Earth as told by xenon, Geochimica Cosmochimica Acta, 244, 56-85, 2019. https://doi.org/10.1016/j.gca.2018.09.017 Open Access. [PDF]
We show how ancient atmospheric concentrations of methane and hydrogen are related to how heavy and light xenon atoms were separated when hydrogen escaped rapidly into space from Earth's oxygen-free atmosphere before  2.4 billion years ago. Xenon isotopes dissolved in tiny inclusions of ancient seawater trapped inside old rocks show that hydrogen escaped  from the ancient Earth at very rapid rates. These xenon data support a theory of Catling et al. (2001, Science) that substantial loss of hydrogen (a reducing agent) greatly oxidized the early Earth, priming the Earth for a tipping point for a big increase of oxygen in Earth's atmosphere around 2.4 billion years ago.

132. S. F. Sholes, J. Krissansen-Totton, D. C. Catling. A maximum subsurface biomass on Mars from untapped free energy: CO and H2 as potential anti-biosignatures, Astrobiology 19, 2019. doi: 10.1089/ast.2018.1835 [PDF].
The cold, dry, and ultraviolet-irradiated surface of Mars is hostile to life. But if microbial life exists below the surface of Mars today, atmospheric carbon monoxide (CO) and hydrogen (H2) could be used for metabolism in reactions such as 2CO + O2 = 2CO2 or 2H2 + O2 = 2H2O. However, atmospheric CO is relatively abundant at 747+/-3 parts per million by volume (ppmv) while the abundance of H2 is ~15 ppmv (compared to 0.1 ppmv CO and 0.5 ppmv H2 in Earth's much thicker  atmosphere). Because these quantities of  gas on Mars remain "uneaten", we can set an upper limit on the biomass that could be below Mars' surface and connected to the atmosphere through porous rock and soil. We show that this biomass limit is ≲1027 cells, which is ≤10-4-10-5 of Earth’s biomass, or  equivalent to ~1 million blue whales or fewer.

131. X. Chen,  F. Z. Teng, D. C. Catling, Fast and precise boron isotopic analysis of carbonates and seawater using multi-collector inductively coupled plasma mass spectrometry, Rapid Communications in Mass Spectrometry,  33: 1169– 1178, 2019.  doi: 10.1002/rcm.8456.

130. M. D. Day & D. C. Catling. Potential aeolian deposition of intra-crater layering: A case study of Henry crater, Mars, GSA Bulletin, https://doi.org/10.1130/B35230.1, 2019.

129. S. F. Sholes, D. R. Montgomery, D. C. Catling, Quantitative high-resolution re-examination of a hypothesized ocean shoreline in Cydonia Mensae, Mars,  Journal of Geophysical Research-Planets, 124,  316– 336 doi.org/10.1029/2018JE005837, 2019.  [PDF].
This paper was highlighted by the American Geophysical Union in "A New Way to Analyze Evidence of Martian Oceans".

2018
128. L. O'Neil, D. C. Catling, W. T. Elam, Optimized Compton fitting and modeling for light element determination in micro-X-ray fluorescence map datasets,  Nuclear Inst. and Methods in Physics Research B, 436, 173-178, 2018. https://doi.org/10.1016/j.nimb.2018.09.023.
This paper concerns preliminary work for an x-ray instrument that is being carried on NASA's Mars 2020 rover.

127. E. A. Goosmann, D. C. Catling, S. M. Som, W. Altermann, and R. Buick Aeolianite grain size distributions as a proxy for large changes in planetary atmospheric density, Journal of Geophysical Research-Planets, 123, 2506–2526, 2018. doi:10.1029/2018JE005723  

126. J. Krissansen-Totton, R. Garland, P. Irwin & D. C. Catling. Detectability of biosignatures in anoxic atmospheres with the James Webb Space Telescope: A TRAPPIST-1e case study, Astronomical Journal, 156, 114. 2018. https://doi.org/10.3847/1538-3881/aad564.
Also: see a BBC News story about this paper. We showed that biosignature gases in an anoxic atmosphere on an exoplanet analogous to the early Earth could be detected using transmission spectroscopy from NASA’s James Webb Space Telescope.

125. J. A. Kegerreis, L. F. A. Teodoro, V. R. Eke, R. J. Massey, D. C. Catling, C. L. Fryer, D. G. Korycansky, M. S. Warren, K. J. Zahnle, Consequences of giant impacts on early Uranus for rotation, internal structure, debris, and atmospheric erosion, Astrophysical Journal, 861, 52, 2018. https://doi.org/10.3847/1538-4357/aac725

124. J. D. Toner & D. C. Catling. Chlorate brines on Mars: Implications for liquids and deliquescence, Earth & Planetary Science Letters 497, 161-168, 2018. https://doi.org/10.1016/j.epsl.2018.06.011

123. M. D. Day & D. C. Catling. Dune casts preserved by partial burial: The first identification of "ghost dunes" on Mars, Journal of Geophysical Research, 123, https://doi.org/10.1029/2018JE005613, 2018.

122. O. R. Lehmer, D. C. Catling, T. M. Hoehler, M. N. Parenteau, The productivity of oxygenic photosynthesis around cool M dwarf stars, Astrophysical Journal 859, 171, 2018.
doi.org/10.3847/1538-4357/aac104
We showed that the photosynthesis on inhabited planets around small red dwarf stars would be light-limited and so may not be sufficient to build up detectable levels of oxygen, even accounting for possible biological adaptation to near-infrared-shifted stellar spectra.

121. J. Krissansen-Totton, G. Arney, D. C. Catling. Constraining the climate and ocean pH of the early Earth with a geological carbon cycle model, Proc. Nat. Acad. Sci. USA 115, 4105-4110, 2018. doi.org/10.1073/pnas.1721296115, Open Access. [E-print]
Using a new empirically-constrained carbon cycle model of the Earth, we showed that the carbonate-silicate cycle moderated the climate of the early Earth, keeping Earth habitable, and maintaining the ocean pH to within a unit of neutral.

120. J. Krissansen-Totton, S. Olson, D. C. Catling. Disequilibrium biosignatures over Earth history and implications for detecting exoplanet life, Science Advances, 4, eaao5747, 2018. doi:10.1126/sciadv.eaao5747. Open Access. [E-print]
We showed that the atmosphere of a planet like the early Earth would have a chemical disequilibrium characteristic of the early biosphere between nitrogen, carbon dioxide, methane and water, and that carbon at each end of the redox spectrum (as CO2 and CH4) forms a detectable combinational biosignature for anoxic planetary atmospheres.

119. D. C. Catling, Krissansen-Totton, J., Kiang, N. Y., Crisp, D., Robinson, T. D., DasSarma, S., Rushby, A., Del Genio, A., Bains, W., Domagal-Goldman, S., Exoplanet biosignatures: A framework for their assessment,  Astrobiology, 18, 709-738, 2018. 10.1089/ast.2017.1737. Open Access.  [E-print]
We set out a generalized framework of Bayesian statistics to assess remotely detected biosignatures in the future from exoplanets, so that probability of the detection of life can be quantified and expressed both scientifically and to the public.

118. S. V. Berdyugina, Kuhn, J.R., Langlois, M., Moretto, G., Krissansen-Totton, J., Grenfell, L., Catling, D., Santl-Temkiv, T., Finster, K., Tarter, J., Shostak, S., Marchis, F., Hargitai, H., Apai, D.: The Exo-Life Finder (ELF) Telescope: New Strategies for Exoplanet Direct Detection, Biosignatures and Technosignatures, Proc. SPIE 10700, Ground-based and Airborne Telescopes VII, 107004I, doi:10.1117/12.2313781, 2018.
This paper describes a ground-based telescope with an equivalent resolving power of >20 m diameter that could detect atmospheric biosignatures on exoplanets around nearby stars.
2017
117. O. R. Lehmer & D. C. Catling. Rocky worlds limited to ~1.8 Earth radii by atmospheric escape during a star’s x-ray and extreme UV saturation, Astrophysical Journal 845, 130. 2017. arxiv.org/abs/1706.02050. [E-print]

116. B. Charnay, G. Le Hir, F. Fluteau, F. Forget, D. C. Catling, A warm or cold early Earth? New insights from a 3-D climate-carbon model, Earth & Planetary Science Letters, 474, 97-109, 2017. [E-print]. doi:10.1016/j.epsl.2017.06.029

115. J. Krissansen-Totton & D. C. Catling. The search for another Earth-like planet and life elsewhere. In What is Life? On Earth and Beyond. (Ed. A. Losch), Cambridge Univ. Press, 30-56, 2017. [E-print].

114. D. C. Catling, S. Stroud. The greening of Green Mountain, Ascension Island,  in M. Joachim, M. Silver (eds.) XXL-XS: New Directions in Ecological Design, ACTAR Publishing, New York, 151-157, 2017. [preprint]

113. J. D. Toner & D. C. Catling, A low-temperature thermodynamic model for the Na-K-Ca-Mg-Cl-SO4 system incorporating new experimental heat capacities in Na2SO4, K2SO4, and MgSO4 solutions, Journal of Chemical and Engineering Data, 62, 3151-3168, 2017. doi: 10.1021/acs.jced.7b00265

112. K. J. Zahnle & D. C. Catling. The "cosmic shoreline": The evidence that escape determines which planets have atmospheres, and what this may mean for  Proxima Centauri b, Astrophysical Journal, 843, 122 (23 pp), 2017, doi: 10.3847/1538-4357/aa7846 [E-print] arxiv.org/abs/1702.03386
A presentation called "The Cosmic Shoreline" describing this topic was submitted to the 2013 Lunar & Planetary Science Conference, along with a companion presentation on impact erosion of atmospheres.

111. J. D. Toner, D. C. Catling, R. S. Sletten. The geochemistry of Don Juan Pond: Evidence for a deep groundwater flow system in Wright Valley, Antarctica, Earth & Planetary Science Letters, 474, 190-197, 2017. doi:10.1016/j.epsl.2017/06/039.  [E-print]

110. R. M. Haberle, D. C. Catling, M. H. Carr, K. J. Zahnle. The early Mars climate system, in The Atmosphere and Climate of Mars (Eds. R. M. Haberle, R. T. Clancy , F. Forget , M. D. Smith , R. W. Zurek ), Cambridge Univ. Press, 526-568, 2017. [E-print] 

109. O. R. Lehmer, D. C. Catling, K. J. Zahnle, The longevity of water ice on Ganymedes and Europas around migrated giant planets, Astrophysical Journal,  839, 32, 2017.
[ https://doi.org/10.3847/1538-4357/aa67ea].  [E-print]  

108. J. Krissansen-Totton & D. C. Catling.  Constraining climate sensitivity and continental versus seafloor weathering with an inverse geological carbon cycle model, Nature Communications, 8, 15423, doi:10.1038/ncomms15423, 2017. [Open Access Paper]. [E-print]. Associated University of Washington new story here.
-- Because the authors believe in transparency and the motto of the AGU, "unselfish cooperation in research," the Python source code for the new carbon cycle model used in this paper is available here.
-- In this paper, we examined indicators in the rocks of past temperatures, atmospheric CO2 levels, and other environmental quantities, going back 100 million years ago, when dinosaurs roamed ice-free polar regions. We found that the Earth has much poorer natural "thermostat” from rock weathering (which removes CO2) than previously thought and allows fairly big swings in temperature. Also, the data indicate that global temperatures eventually go up 5-6 C for CO2 doublings, which is about twice the 3 C that's projected over centuries for global warming. Having tested this analysis on a fairly data-rich period of Earth history, similar analysis can now be applied with more confidence to understand the climate of the early Earth when life was just starting or the habitability of Earth-like exoplanets.

107. S. F. Sholes, M. L. Smith, M. W. Claire, K. J. Zahnle, D. C. Catling. Anoxic atmospheres on Mars driven by past volcanism: Implications for past environments and life, Icarus, 290, 46-62, 2017. doi:10.1016/j.icarus.2017.02.022 [E-print]  

106. J. D. Toner & D. C. Catling, A low-temperature thermodynamic model for the Na-K-Ca-Mg-Cl system incorporating new experimental heat capacities in KCl, MgCl2, and CaCl2 solutions, Journal of Chemical and Engineering Data, 62, 995-1010, 2017. http://dx.doi.org/10.1021/acs.jced.6b00812

2016
105. B. L. Ehlmann, F. S. Anderson, J. Andrews-Hanna, D. C. Catling, et al. The sustainability of habitability on terrestrial planets: Insights, questions, and needed measurements from Mars for understanding the evolution of Earth-like worlds, Journal of Geophysical Research-Planets, doi:10.1002/2016JE005134, 2016. [Open Access Paper].

104. R. C. Payne, A. V. Britt, H. Chen, J. F. Kasting, D. C. Catling. The response of Phanerozoic surface temperature to variations in atmospheric oxygen concentration, J. Geophys. Res. Atmos. 121, doi:10.1002/2016JD025459 , 2016.

103. S. M. Som, R. Buick, J. W. Hagadorn, T. S. Blake, J. M. Perreault, J. P. Harnmeijer, D. C. Catling. Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels, Nature Geoscience, doi:10.1038/ngeo2713, 2016. [E-print].
We present measurements suggesting the surprising discovery that the Earth's atmosphere was thinner than today's air by a factor of two or more. See a university news release or news commentary at Science magazine; also a clip from BBC World Service radio of Roger Buick talking about the discovery.

102. G. M. Marion, D. C. Catling, J. S. Kargel, J. K. Crowley. Modeling calcium sulfate chemistries with application to Mars, Icarus 278, 31-37, 2016. 10.1016/j.icarus.2016.05.016

101. J. Krissansen-Totton, D. Bergsman, D. C. Catling, On detecting biospheres from chemical disequilibrium in planetary atmospheres, Astrobiology 16, 39-67, 2016.
    [E-print]  
It took us a considerable amount of time to find suitable databases and write computer code for this project. So, to encourage unselfish cooperation in research, the Matlab code and thermodynamic databases used to calculate available Gibbs energy in planetary atmospheres in this paper are available here within a zipped folder for download: Disequilibium_Source_code.zip
Please be sure to read the ReadMe.txt file and all comments to use the code.

A great discussion of this paper appeared in a BBC Sky At Night magazine piece.

100. J. Krissansen-Totton, E. Schwieterman, B. Charnay, G. Arney, T. D. Robinson, V. Meadows, D. C. Catling, Is the Pale Blue Dot unique? Optimized photometric bands for identifying Earth-like planets, Astrophysical Journal,  817, 31, 2016. [E-print].
           A nice summary of this paper was blogged in astrobites.

99. J. D. Toner & D. C. Catling, Water activities of NaClO4, Ca(ClO4)2 and Mg(ClO4)2 brines from experimental heat capacities: Water activity >0.6 below 200 K, Geochimica Cosmochimica Acta, 181, 164-174, 2016.  [E-print].

2015
98. P. Pogge von Strandmann, E. E. Stüeken, T. Elliott, S. W. Poulton, C. M. Dehler, D. E. Canfield, D. C. Catling. Selenium isotope evidence for post-glacial oxygenation trends in the Ediacaran ocean, Nature Communications, 6:10157, doi: 10.1038/ncomes10157, 2015. [Open Access Paper].
        A nice discussion of this paper was blogged on Centauri Dreams.

97. J. D. Toner, D. C. Catling, B. Light, A revised Pitzer model for low-temperature soluble salt assemblages at the Phoenix site, Mars. Geochimica Cosmochimica Acta, 166, 327-343, 2015. [E-print].

96. D. C. Catling, Planetary Atmospheres. In G. Schubert (ed.), Treatise on Geophysics (2nd Ed.), vol. 10, Elsevier, New York, 429-472, 2015. [E-print].
            Reviews essentials of planetary atmospheres--mainly physics with some chemistry.

95. J. Krissansen-Totton, R. Buick, D. C. Catling. A statistical analysis of the carbon isotope record from the Archean to Phanerozoic and implications for the rise of oxygen, American Journal of Science, 315, 275-316, 2015. [E-print]
For complete transparency and to encourage cooperation in research, the isotope data and computer source code used in this paper are freely available here.

94. J. D. Toner, D. C. Catling, B. Light, Modeling salt precipitation from brines on Mars evaporation versus freezing origin for soil salts,  Icarus, 250, 451-461, 2015. doi:10.1016/j.icarus.2014.12.013. [E-print].
    We show that salts found in the soil at the landing site of NASA's Phoenix Mars lander were not formed by evaporation of an aqueous salty solution but could have formed as a salty liquid froze. In freezing, a salty solution becomes more and more concentrated as ice forms, and certain types of salts precipitate, producing a chemical mixture diagnostic of an origin by freezing. Thus, the chemistry constrains the past environment, which was cold.

93. E. E. Stüeken, R. Buick, A. Bekker, D. Catling, J. Foriel, B. M. Guy, J. C. Kah, H. G. Macel, K. P. Montanez, S. W. Poulton, The evolution of the global selenium cycle: Secular trends in Se isotopes and abundances, Geochimica Cosmochimica Acta, 162, 109-125.

92. E. Pecoits, M. L. Smith, D. C. Catling, P. Philippot, A. Kappler, K. O Konhauser,  Atmospheric hydrogen peroxide and Eoarchean iron formations, Geobiology 13, 1-14, 2015. doi:10.1111/gbi.12116

2014
91. D. C. Catling. Mars Atmosphere: History and Surface Interactions. In: T. Spohn,  D. Breuerm, T. V. Johnson (Eds.), Encyclopedia of the Solar System (3rd Edition), Elsevier, 343-357, 2014. [ E-print ]. [This book won the 2015 American Publishers Award for Professional and Scholarly Excellence (PROSE) in the Cosmology & Astronomy category].

90. G. M. Marion, D. C. Catling, J. S. Kargel, J. I. Lunine, Modeling nitrogen-gas, -liquid, -solid chemistries at low temperature (173-298 K), Icarus 236, 1-8, 2014.

89. D. C. Catling, The Great Oxidation Event Transition, In Treatise on Geochemistry (2nd. Ed.), edited by H. D. Holland and K. K. Turekian, vol. 6, Elsevier, Oxford, 177-195, 2014. http://dx.doi.org/10.1016/B978-0-08-095975-7.01307-3  [E-print].

88. J. D. Toner, D. C. Catling, B. Light, Reanalysis of Wet Chemistry Laboratory data at the Phoenix Lander site on Mars with implications for the soluble soil salts, Geochim. Cosmochim. Acta, doi:10.1016/j.gca.2014.03.030, 142-168, 2014. [E-print].

87. M. L. Smith, M. W. Claire, D. C. Catling, K. J. Zahnle, The formation of sulfate, nitrate and perchlorate salts in the martian atmosphere,  Icarus, 231, 51-64, 2014. Open Access full article
Using a photochemical simulation, we calculate deposition fluxes of salts formed in the ancient martian atmosphere by oxidation of volcanic gases. The resulting sulfate soil concentrations are consistent with observations. Results also show that pernitric acid forms predominantly in Mars' atmosphere rather than nitric acid. Purely gas-phase reactions are insufficient to account for perchlorate in the soil so that gas-solid reactions (which are currently unknown) are implied.

86. T. D. Robinson & D. C. Catling, Common 0.1 bar tropopause in thick atmospheres set by pressure-dependent infrared transparency, Nature Geoscience,  7, 12-15, 2014. doi:10.1038/NGEO2020 [E-print].
The minimum air temperature between the troposphere (the lowest atmospheric layer where temperature declines with altitude) and stratosphere (where temperature increases with altitude in an 'inversion') occurs a pressure of about 0.1 bar on Earth, Titan, Jupiter, Saturn, Uranus and Neptune. We used the physics of radiation to explain why the tropopause temperature minimum in these very different atmospheres occurs at the comåmon pressure near 0.1 bar. Physics suggests that a tropopause temperature minimum around 0.1 bar should be a fairly general rule for planets with stratospheric temperature inversions. This rule could constrain the atmospheric structure on exoplanets and hence their surface temperature and habitability. Accompanying Univ. of Washington news story.
Also a nice summary of the paper was blogged in astrobites.
And a layperson's summary is given by us: D. C. Catling & T. D. Robinson "Why the tropopause temperature minimum occurs at a common pressure near 0.1 bar in thick atmospheres of planets and moons"

85. J. D. Toner, D. C. Catling, B. Light, The formation of supercooled brines, viscous liquids, and low-temperature glasses on Mars, Icarus 233, 36-47, 2014, doi:10.1016/j.icarus.2014.01.018. [E-print].
We report a discovery that perchlorate salts tend not to crystallize if cooled even at relatively slow rates but become gradually more viscous and turn into glass (amorphous, non-crystalline solids). Glasses are great for preserving microorganisms, so this is relevant for looking for signs of microbial life on Mars and other cold bodies.

84. P. Pogge von Strandmann, C. D. Coath, D. C. Catling, S. W. Poulton, T. Elliott, Analysis of mass dependent and mass independent selenium isotope variability in black shales, Journal of Analytical Atomic Spectrometry, 29, 1648-1659, 2014. doi:10.1039/c4ja00124a

83. K. J. Zahnle & D. C. Catling, Waiting for oxygen, in Special Paper 504: Earth's Early Atmosphere and Surface Environment (Shaw, G. H., ed.), Geological Society of America Conference Proceedings, 2014, 37-48. [E-print].

2013
82. Marion, G. M., Kargel, J. S., Crowley, J. K., Catling, D. C., Sulfite-sulfide-sulfate- carbonate equilibria with applications to Mars, Icarus, 225, 342-351, 2013. [E-print].

81. S. M. Som, J. W. Hagadorn, W. A. Thelen, A. R. Gillespie, D. C. Catling, R. Buick, Quantitative discrimination between geological materials with low density contrast by high resolution X-ray computer tomography: An example using amygdule size-distribution in ancient lava flows, Computers & Geosciences, 54, 231-238, 2013, doi: 10.1016/j.cageo.2012.11.019 .[E-print].

80. P. B. Niles, D. C. Catling, G. Berger, E. Chassefiere, B. L. Ehlmann, J. Michalski, R, Morris, S. W. Ruff, B. Sutter, Carbonates on Mars, Space Science Reviews, 174, 301-328, 2013. [E-print].

79. B. L. Ehlmann, G. Berger, N. Mangold, J. R. Michalski, D. C. Catling, S. W. Ruff, Eric Chassefière, P. B. Niles, V. Chevrier, F. Poulet, Geochemical consequences of widespread clay mineral formation in Mars' ancient crust, Space Science Reviews, 174, 329-364, 2013.
[E-print].

78. E. E. Stüeken, J. Foriel, B. K. Nelson, R. Buick, D. C. Catling. Selenium isotope analysis of organic-rich shales: Advances in sample preparation and isobaric interference correction, J. Analytical Atomic Spectroscopy, doi:10.1039/C3JA50186H, 2013.

77. K. J. Zahnle, D. C. Catling,  M. W. Claire. The rise of oxygen and the hydrogen hourglass, Chemical Geology, 362, 26-34, 2013. (Open Access; just click on the title)

76. D. C. Catling. How long will the Earth remain habitable? Sky & Telescope Special Edition: Astronomy's 60 Greatest Mysteries, 2013, p.16-17.

2012
75. E. E. Stüeken, D. C. Catling, R. Buick, Contributions to Late Archaean sulphur cycling by life on land, Nature Geoscience, 5, 722-725, doi:10.1038/ngeo1585, 2012. Accompanying University of Washington News Story. [E-print]

74. T. D. Robinson & D. C. Catling, An analytic radiative-convective model for planetary atmospheres, Astrophysical Journal, 757, 104. doi:10.1088/0004-637X/757/1/104. [E-print] Because we believe in unselfish cooperation in research, the IDL (Interactive Data Language) source code used in this paper is available to everyone here:
        AN_RC_MOD.pro , EXAMPLE.pro, EXAMPLE_W_FLUXES.pro

73. J. F. Kasting, D. C. Catling, K. J. Zahnle, Atmospheric oxygenation and volcanism, Nature 487, E1, 2012.

72. E. Sefton-Nash, D. C. Catling, S. E. Wood, P. Grindrod, Topographic, spectral and thermal inertia analysis of interior layered deposits in Iani Chaos, Mars,  Icarus, 221, 20-42, 2012. doi:10.1016/j.icarus.2012.06.036  [E-print]

71. S. M. Som, D. C. Catling, J. P. Harnmeijer, P. M. Polivka, R. Buick. Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints, Nature, 484, 359-362, 2012.  doi:10.1038/nature10890
- We use fossil raindrop impressions in 2.7 billion-year-old rocks made of volcanic ash to determine an upper limit on the air density and hence the barometric pressure at that time. The method use calibration experiments of drops falling into modern, comparable ash. This is the first time constraints on the barometric pressure on the early Earth have been made using direct physical geology. Air pressure was probably less than ~50-110% of today's value. (University of Washington Press Release ).

70. M. W. Claire, J. Sheets, M. Cohen, I. Ribas, D.C. Catling, The evolution of solar flux from 2 nm to 160 microns: Quantitative estimates for planetary studies, Astrophysical Journal 757, 95, 2012. doi:10.1088/0004-637X/757/1/95 [E-print]

69. G. M. Marion, J. S. Kargel, D. C. Catling, J. I Lunine, Modeling ammonia-ammonium chemistries in the outer planet regions, Icarus 220, 932-946, 2012. [E-print]

2011

68. D. Schulze-Makuch et al. (inc. D. C. Catling). A two-tiered approach to assessing the habitability of exoplanets, Astrobiology, 11,  doi:10.1089/ast.2010.0592, 2011.
- In the future, thousands of exoplanets will be known, so how will we judge whether they might be habitable from basic astronomical parameters? This paper presents some metrics and considerations of what makes a planet habitable.

67. D. C. Catling. Oxygenation of the Earth's atmosphere. In Encyclopedia of Astrobiology (Eds. M. Gargaud et al.),  Springer, 1200-1208, 2011. [E-print]

66. G. M. Marion, D. C. Catling, J K. Crowley, J. S. Kargel. Modeling hot spring chemistries with applications to Martian silica formation, Icarus, 212, 629-642 doi:10.1016/j.icarus.2011.01.035. [E-print]

65. K. J. Zahnle, R. S. Freedman, D. C. Catling. Is there methane on Mars?, Icarus, doi:10.1016/j.icarus.2010.11.027, 2011.
- We argue that reports of rapidly-varying methane on Mars (which has led to much speculation about biogenic sources) violate basic principles of redox chemistry.  This led us to uncover hitherto undocumented interferences in the observations, which cast doubt on the robustness of the data. [E-print]

2010

64. P. Withers. D. C. Catling.  Observations of atmospheric tides on Mars at the season and latitude of the Phoenix atmospheric entry, Geophysical Research Letters, 37, L24204, doi:10.1029/2010GL045382, 2010.
- The first in situ atmospheric structure from the polar regions of Mars. We report on the atmospheric structure that we derive from accelerometer data obtained during the descent of the Phoenix Lander to the surface of Mars in 2008.  The temperature profile of the atmosphere was strongly influenced by thermal tides, i.e., global oscillations caused by day-night heating of the atmosphere by the Sun that are also influenced by the global-scale topography of Mars. [E-print]

63. F. Tian, M. W. Claire, J. D. Haqq-Misra, M. Smith, D. C. Crisp, D. Catling, K. Zahnle, J. F. Kasting. Photochemical and climate consequences of sulfur outgassing on early Mars, Earth & Planetary Science Letters, 295, 412-418 , 2010. [E-print]
- We show that the net effect of volcanic sulfur gases on early Mars was to cool the planet because of the formation of reflective sulfate aerosols. That this is so should be intuitive because sulfate aerosols cool Earth and Venus by reflecting sunlight. However,  papers previously published by others had argued that SO2 gas would keep early Mars "warm and wet". Although SO2 is a greenhouse gas, prior studies did not account for the larger cooling effect of sulfate aerosols.

62. S. P. Kounaves, M. H. Hecht, J. Kapit, R. C. Quinn, D.C. Catling, B. C. Clark, D. W. Ming, et al., Soluble sulfate in the Martian soil at the Phoenix landing site, Geophysical Research Letters, 37, L09201, 2010. doi:10.1029/2010GL042613
- The first measurement of the amount of soluble sulfate in the soil on Mars

61. S. P. Kounaves, S. T. Stroble, R. M. Anderson, Q. Moore, D. C. Catling, S. Douglas,
C. P. McKay, D. W. Ming, P. H. Smith, L. K. Tamppari, A. P. Zent, Discovery of natural perchlorate in the Antarctic Dry Valleys and its global implications, Environmental Science and Technology, DOI: 10.1021/es9033606, 2010.
 - The first detection of perchlorate (ClO4-) salts in the Antarctic Dry Valleys.

60. G. M. Marion, D. C. Catling, M. W. Claire, K. J. Zahnle. Modeling aqueous perchlorate chemistries with applications to Mars, Icarus, 207, 675-685, 2010. [E-print]

59.   D. C. Catling, M. W. Claire, K. J. Zahnle, et al.,  Atmospheric origins of perchlorate on Mars and in the Atacama, J. Geophys. Res., 115, E00E11, doi:10.1029/2009JE003425, 2010. See First Results From the Phoenix Mission to Mars Special Issue. [E-print]
- The first photochemical model to calculate fluxes of atmospheric salts that bulit up the salt deposits (nitrate and perchlorate) in the Atacama desert of Chile. Also, we discuss chemical pathways to form perchlorate on Mars.

58. S. P. Kounaves et al. (incl. D. C. Catling),  The wet chemistry experiments on the 2007 Phoenix Mars Scout Lander Mission: Data analysis and results, J. Geophys. Res., 115, E00E10, doi:10.1029/2009JE003424, 2010.
              - The first direct measurement of soluble soil salts on Mars made by adding soil on                 Mars to water and measuring anions and cations with ion selective electrodes.

57. D. Fisher et al. (incl. D. C. Catling), A perchlorate-lubricated brine deformable bed could facilitate flow of the Mars North Polar Cap: Possible mechanism for water table recharging, J. Geophys. Res., 115, E00E12, doi:10.1029/2009JE003405, 2010. [E-print]
    A paper predicting that a subpolar lake under one or both of the polar caps of Mars might be possible as a result of low-temperature perchlorate brines.

56. C. Stoker, A. Zent, D. C. Catling et al., Habitability of the Phoenix Landing Site, J. Geophys. Res., 115, E00E20, 2010. doi:10.1029/2009JE003421.


2009

55. Renno, N. O., B. J. Boss, D. Catling, et al., Possible physical and thermodynamical evidence for liquid water at the Phoenix landing site, J. Geophys. Res., 114, E00E03, doi:10.1029/2009JE003362, 2009.

54. Smith, P. H., L. Tamppari, R. E. D. Arvidson, D. S. Bass, D. Blaney, W. V. Boynton, A. Carswell, D. C. Catling et al., H2O at the Phoenix landing site,  Science, 325, 58-61, 2009.

53. M. H. Hecht et al. (incl. D. C. Catling), Detection of perchlorate and soluble chemistry of  martian soil: Findings from the Phoenix Mars Lander, Science, 325, 64-67, 2009.

52. W. V. Boynton et al. (incl. D. C. Catling), Evidence for calcium carbonate at the Phoenix landing site, Science, 325, 61-64, 2009.

51. D. C. Catling and K. J. Zahnle, The escape of planetary atmospheres, Scientific American, 300, 36-43, May 2009. [E-print]

50.  G. M.  Marion, J. S. Kargel and D. C. Catling. Br/Cl partitioning in chloride minerals in the Burns Formation on Mars, Icarus, 200, 436-445, 2009.

49. D. C. Catling, Atmospheric Evolution of Mars. In: V. Gornitz (ed.) Encyclopedia of Paleoclimatology and Ancient Environments, Springer, Dordrecht, 2009, pp.  66-75, [preprint]

In celebration of  the bicentennial of Charles Darwin's birth on February 12, 1809:
48. D. C. Catling, Revisiting Darwin's Voyage, in Darwin: For the Love of Science, A. Kelly, M. Kelly, B. Dolan, J. Hodge, M. Waithe, A. C. Grayling, K.  Ward, G. Dyson, and D. C. Catling. Bristol Cultural Development Partnership, 2009, pp. 240-251. [preprint] [E-print]

2008
47. Smith, P. H., L. Tamppari, R. E. D. Arvidson, D. S. Bass, D. Blaney, W. V. Boynton, A. Carswell, D. C. Catling et al., The Phoenix mission to Mars, J. Geophys. Res., 13, E00A18,  doi:10.1029/2008JE003083.
Describes the first space probe to successfully land in the "arctic" equivalent of the planet Mars.

46.  P. A. Taylor, D. C. Catling, M. Daly, C. S. Dickinson, H. O. Gunnlaugsson, A-M. Harri, C. F. Lange, Temperature, pressure and wind instrumentation on the Phoenix meteorological package, J. Geophys. Res., 113, EA0A10, doi:10.1029/2007JE003015, 2008. [E-print]

45.  G. M.  Marion, J. S. Kargel and D. C. Catling. Modeling ferrous-ferric iron chemistry with application to Martian surface geochemistry, Geochimica et Cosmochimica Acta 72, 242-266, 2008. [E-print]

44. D. C. Catling. Where did the oxygen in our atmosphere come from? In: The Seventy Great Mysteries of the Natural World, M. J. Benton (Ed.), Thames and Hudson, London, pp.69-71, 2008. [E-print]

43. E. Sefton-Nash and D. C. Catling. Hematitic concretions at Meridiani Planum, Mars: Their growth timescale and possible relationship with iron sulfates, Earth Plan. Sci. Lett.,  269, 366-376, 2008. [E-print]

42. K. J. Zahnle, R. M Haberle, D. C. Catling, J. F. Kasting. Photochemical instability of the ancient Martian atmosphere, J. Geophys. Res, 113, E11004, doi:10.1029/2008JE003160, 2008. [E-print]

41.  D. C. Catling. Earth's early atmosphere, Catalyst: Secondary Science Review, 18, 16-18, 2008.  (an article aimed at secondary school students) [E-print]
2007
40. D. C. Catling, Mars: Ancient fingerprints in the clay, Nature 448, 31-32, 2007. [E-print] 
    39. D. C. Catling, M. W. Claire, and K. J. Zahnle, Anaerobic methanotrophy and the rise of oxygen, Phil. Trans. Roy. Soc. A 365, 1867-1888, 2007. [E-print] 
38. D. C. Catling and J. F. Kasting, Planetary Atmospheres and Life, In W. Sullivan , J. Baross (eds.) Planets and Life: The Emerging Science of Astrobiology, Cambridge University Press,  p. 91-116, 2007. [E-print]
 
37. D. Catling, Book Review, Genesis: The Scientific Quest for Life's Origins by Robert M. Hazen,  American Mineralogist 92, 1543, 2007. [E-print]

2006

36. D. C. Catling, and R. Buick. Introduction to Special Issue: Oxygen and Life in the Precambrian, Geobiology, vol. 4, 225-226, 2006. [E-print]
35. K. J. Zahnle, M. W. Claire, and D.C. Catling, The loss of mass-independent fractionation in sulfur due to a Paleoproterozoic collapse of atmospheric methane, Geobiology, vol. 4, 271-283, 2006. [E-print]
    • A 1D numerical photochemical model is used to study the atmospheric photochemistry of oxygen, methane, and sulphur after the advent of oxygenic photosynthesis. We show that collapse of atmospheric methane in the early Proterozoic aeon to levels of  ~10s of ppmv provides the best explanation of the disappearance of mass-independent fractionation in sulphur isotopes.
34. M. W. Claire, D.C. Catling and K. J. Zahnle, Biogeochemical modeling of the rise in atmospheric oxygen. Geobiology, vol. 4, 239-269, 2006. [E-print]
    • Here we present analytical and numerical computations for how the Earth's early atmosphere transitioned to an O2-rich state about 2.4. billion years ago. Understanding this transition is important for life on Earth because the rise of O2 allowed a stratospheric ozone layer to develop and allowed a greater variety of oxygen-dependent eukaryotic life.
33. Mix, L., et al., The astrobiology primer: An outline of general knowledge - Version 1, 2006. Astrobiology 6,  735-813, 2006.

32. Marion G. M., Catling D. C., Kargel J. S., Modeling gas hydrate equilibria in electrolyte solutions. CALPHAD - Computer Coupling of Phase Diagrams and Thermochemistry, 30, 248-259, 2006.

31. G. T. Delory, W. M. Farrell, S. Atreya, N. O. Renno, A-S. Wong, S. A. Cummer, D. D. Sentman, J. R. Marshall, S. C. R. Rafkin and D. C. Catling, Oxidant enhancement in Martian dust devils and storms: Storm electric fields and electron dissociative attachment. Astrobiology 6, 453-454, 2006.
30. S. K. Atreya, A-S Wong, N. O. Renno, W. M. Farrell, G. T. Delory, D. D. Sentman, S. A. Cummer, J. R. Marshall, S. C. R. Rafkin, D. C. Catling, Oxidant enhancement in Martian dust devils and storms: Implications for life and habitability, Astrobiology, 6, 439-450, 2006.
29. D.C. Catling, Comment on "A Hydrogen-rich Early Earth Atmosphere". Science 311, 38a, 2006.
    • Here I commented on a paper by Tian et al., noting that Earth's early thermosphere, under the high extreme ultraviolet flux of the early Sun, would have been hot enough for hydrogen to escape readily so that hydrogen would not accumulate to high abundance. My back-of-envelope calculations are supported by independent detailed calculations of early Earth's thermosphere by Kulikov et al. (2006) Space Sci. Rev., submitted. 
28. D.C. Catling, S. E. Wood, C. Leovy, D. R. Montgomery, H. Greenberg, C. R. Glein, J. M. Moore, Light-toned layered deposits in Juventae Chasma, Mars, Icarus, 181, 26-51, 2006.[E-print]
    • This paper discusses the origin of enigmatic sulfate deposits, as large as mountains, in a deep chasm on Mars. Using spacecraft data, we made a new geomorphic map of Juventae Chasma and the deposits in its interior.
27. D. C. Catling, C. Leovy, Mars Atmosphere: History and Surface Interactions. In: L. McFadden, P. Weissman (eds.) Encyclopedia of the Solar System, Academic Press, 2006, p.301-314. [preprint]  [E-print]
2005

26. D. C. Catling and M. Claire, How Earth's atmosphere evolved to an oxic state: A status report, Earth Planet. Sci. Lett., 237, 1-20, 2005. [E-print]
    • A review of the how the level of molecular oxygen (O2) in the Earth's atmosphere has changed over the last 4 billion years and what caused the changes, to the best of our knowledge.
25. D C. Catling, Twin studies on Mars. Nature 436, 42-43, 2005. [E-print]
        Invited commentary on the results of the Mars Exploration Rovers.
24. D. W. Beaty, S. M. Clifford, L. E. Borg, D. Catling et al., Key science questions from the Second Conference on Early Mars: Geologic, hydrologic, climate evolution, and the implications for life, Astrobiology , 5, 663-689, 2005.
23. D. C. Catling, C.R. Glein, K.J. Zahnle, and C. P. McKay. Why O2 is required by complex life on habitable planets and the concept of planetary "oxygenation time",  Astrobiology, 5, 415-438, 2005. [E-print] Commentary on this paper by Norm Sleep.
    • We explain how O2 provides the highest feasible energy release per electron transfer for carbon-based life, a universal property set by the limits of the periodic table. We also calculate theoretical biomass spectra for anaerobic (non-O2-using) life, which shows why such life does not grow large and complex. The upshot is that the evolution of water-splitting metabolism (photosynthesis) and subsequent atmospheric evolution are the important factors for determining the distribution of complex life on planets elsewhere in our galaxy and in the universe.
    • See also "Why E.T. would also breathe oxygen", Forbes Magazine.

22. D. C. Catling, Coupled evolution of Earth's atmosphere and biosphere. In: A. Kleidon, R. Lorenz (eds.) Non-equilibrium Thermodynamics and the Production of Entropy: Life, Earth and Beyond, Springer, 2005, p.191-206. [E-print]
    • Of solar system planets with atmospheres, the Earth is the sunniest in terms of flux reaching its surface. Earth also has an anomalous atmosphere, chemically and dynamically. The chemistry is in a low entropy state, pushed far from thermodynamic equilibrium by surface gas fluxes. Dynamically, the Earth has the most unpredictable weather (e.g., compare Jupiter's Great Red Spot) and the slowest jets. In this paper, I discuss how life and entropy production have roles in producing Earth's weird atmosphere, which in turn allows life to flourish.
21. G. M. Marion, J. S. Kargel, D. C. Catling, S. D. Jakubowski. Effects of pressure on aqueous chemical equilibria at subzero temperatures with applications to Europa, Geochim. Cosmochim. Acta 69, 259-274, 2005.

2004
20. D. C. Catling, Planetary Science: On Earth, as it is on Mars? Nature 429, 707-708, 2004. [E-print]
    • A "News and Views" piece that gives recent thinking on Martian hematite concretions (nicknamed "blueberries") that were discovered by the Opportunity Mars rover. The write-up discusses similar (but different!) phenomena on Earth, in Utah.

19. W. M. Farrell, P. H. Smith, G. T. Delory, G. B. Hillard, J. R. Marshall, D. Catling et al., Electric and magnetic signatures of dust devils from the 2000-2001 MATADOR desert tests, J. Geophys. Res., 109(E), doi:10.1029/2003JE002088, 2004. [E-print] 
 18. D. C. Catling, M. W. Claire, K. J. Zahnle, Understanding the evolution of atmospheric redox state from the Archaean to the Proterozoic, In: Reimold, W.U. and Hofmann, A. (Eds.), Abstract volume, Field Forum on Processes on the Early Earth, Kaapvaal Craton, S. Africa, July 4-9, 2004, p.17-19.  [E-print] 
    • Here, we presented a quantitative model of the rise of oxygen around 2.4 billion years ago.  We showed how the rise of O2 occurred when the flux of organic carbon burial (which is the source of O2) exceeded the geothermal flux of reductants (such as reduced volcanic and metamorphic gases that react with oxygen, as well as hydrothermal cations such as ferrous iron). We also showed that as  O2 rises, ultraviolet shielding of the troposphere by ozone causes a positive feedback on the increase in atmospheric oxygen.  See the subsequent paper by Claire et al. (2006) for full details.

2003

17. D. M. Tratt, M. H. Hecht, D. C. Catling, E. C. Samulon, and P. Smith, In situ measurement of dust devil dynamics: Toward a strategy for Mars J. Geophys. Res., 108, doi:10.1029/2003JE002161, 2003. [E-print]
16. J. F. Kasting and D. C. Catling, Evolution of a habitable planet, Annual Reviews of Astronomy and Astrophysics, 41, 429-463, 2003.[E-print]
    • In this paper, we review why Earth's climate has remained conducive to life on Earth for the past 3.5 billion years.
15. D. C. Catling and J. M Moore, The nature of coarse-grained crystalline hematite and its implications for the early environment of Mars, Icarus, 165, 277-300, 2003.[E-print]
    • Gray, crystalline hematite is a mineral that has been found in certain locations on Mars, in particular at the landing site of the NASA Mars Exploration Rover called "Opportunity" that landed in 2004. In this paper, before we knew about the Opportunity findings, we discussed  the possible environments in which gray hematite might have formed on Mars.
14. G. M. Marion, D. C. Catling , and J. S. Kargel, Modeling aqueous ferrous iron chemistry at low temperatures with application to Mars, Geochem. Cosmochem. Acta, 67, 4251-4266, 2003. [E-print]

13.  D. Catling and K. Zahnle, Evolution of atmospheric oxygen, in Encyclopedia of Atmospheric Sciences (Ed. J. Holton, J. Curry, J. Pyle), Academic Press, 754-761, 2003. [E-print]

2002
D. C. Catling, K. J. Zahnle, and C. P. McKay, What caused the second rise of O2 in the late Proterozoic? Methane, sulfate, and irreversible oxidation, Astrobiology 2, 569, 2002.  [E-print]
  • In this conference paper, we presented an idea -- completely new at the time -- that methane could have been at high levels (10s or 100s of ppmv) during the middle Proterozoic. We argued that CH4 could have still been an important greenhouse gas if there had been a large (biogenic) CH4 flux from the large areas of anoxic seafloor in the Proterozoic. We also noted how this could drive a second rise of atmospheric O2 in the Neoproterozoic because of decomposition of methane in the upper atmosphere and associated hydrogen escape to space. Finally, we noted that a lot of sedimentary sulfide should have been subducted in the Proterozoic (because of large areas of euxinia), which would also oxidize the surface environment over time.
12. M. R. Patel, J. C. Zarnecki, and D. C. Catling, Ultraviolet radiation on the surface of Mars and the Beagle 2 ultraviolet sensor, Planetary and Space Science, 2, 569, 2002.

2001
11. D. C. Catling, K. J. Zahnle, and C. P. McKay, Biogenic methane, hydrogen escape, and the irreversible oxidation of early Earth, Science, 293, 839-843, 2001. [E-print]
    • In this paper, we advanced a theory to answer the question of why the Earth's atmosphere became oxygen-rich about 2.4-2.2 billion years ago. This transition was an important event in Earth's history because all complex life forms (animals and multicellular plants) rely on molecular oxygen (O2). Consequently, understanding the rise of oxygen is critical for understanding biological evolution on our planet.

10.  J. C. Bridges, D. C. Catling, J. M. Saxton, T. D. Swindle, I. C. Lyon and M. M. Grady, Alteration assemblages in Martian meteorites: Implications for near-surface processes, in Chronology and Evolution of Mars , Kluwer Academic, New York, 2001, pp.365-392. [E-print]
2000

9. C. S., Cockell, D. C. Catling, W. L. Davis, K. Snook, R. L. Kepner, and P. Lee, and McKay, C. P., The ultraviolet environment of Mars: Biological implications past, present, and future. Icarus, 146, 343-459, 2000. [E-print]
8. J. K. Reynolds, D. Catling, R. C. Blue, N. I. Maluf, and T. Kenny, Packaging a piezoresistive pressure sensor to measure low absolute pressures over a wide sub-zero temperature range, Sensors and Actuators, A83, 142-149, 2000. [E-print]
1999
7. D. C. Catling. A chemical model for evaporites on early Mars: Possible sedimentary tracers of the early climate and implications for exploration, J. Geophys. Res., 104, 16,453-16,470, 1999. [E-print.]
6. S. Smrekar, D. Catling, R. Lorenz, J. Magalhaes, M. Meyer, J. Moersch, P. Morgan, J. Murphy, B. Murray, M. Presley-Holloway, A. Yen, and A. Zent, Deep Space 2: The Mars Microprobe Mission, J. Geophys. Res., 104, 27013-27030, 1999. [E-print]
5. C. S. Cockell, D. C. Catling and H. F. Waites. Insects at low-pressures: Applications to artificial ecosystems and implications for global windborne distribution, Life Support and Biosphere Sci., 6, 161-167, 1999.

prior to 1999

4. D. C. Catling. High sensitivity silicon capacitive sensors for measuring medium vacuum gas pressures, Sensors and Actuators, A64, 157-164, 1998. [E-print.]
3. R. M. Haberle and  D. C. Catling, A micro-meteorological mission for global network science on Mars: Rationale and measurement requirements, Planet. Space Sci. 44, 1361-1384, 1996. [E-print.]
    • This article was about a concept that Bob Haberle and I  came up with for measuring the global climate system on Mars using a network of miniature, automated weather stations. Later, along with other scientists and engineers, we developed a detailed NASA mission concept called "Pascal" to do this. Pascal is yet to fly, but such a mission will be an essential precursor for a future human mission. 
2. M. M. Joshi, S. R. Lewis, P. L. Read and D. C. Catling. Western boundary currents in the Martian atmosphere: Numerical simulations and observational evidence, J. Geophys. Res.  100, 5485-5500, 1995. [E-print.]
1. M. M. Joshi, S. R. Lewis, P. L. Read and D. C. Catling. Western boundary currents in the atmosphere of Mars, Nature, 367, 548-551, 1994.
    • Western boundary currents are important fluid flows  in the climate system on Earth. The Gulf Stream in the north Atlantic ocean helps keep western Europe warm and the East African Jet in the atmosphere plays an important role in the Asian monsoon. In this paper, we pointed out how western boundary currents are a significant feature of the atmosphere of Mars.[E-print.]

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