David Catling, University of Washington, Seattle

David Catling
davidc@atmos.washington.edu

Welcome to the webpage of David Catling at the University of Washington (UW), Seattle.

I am jointly affiliated with UW's Astrobiology Program and the Department of Atmospheric Sciences.

I am also Adjunct Professor in the Astronomy Department.

Research Interests:

Planetary Atmospheres and Climate; The Coupled Evolution of Planetary Surfaces and Atmospheres.
Evolution of the Earth's Atmosphere and the Co-evolution of Life and Biogeochemical Cycles
Involvement with NASA's missions to the planet Mars :

data analysis from the Mars Global Surveyor and Mars Odyssey orbiters
Science Team member for NASA's Phoenix lander (to be launched in 2007)

Mailing Address:

Dept. of Atmospheric Sciences
University of Washington
Box 351640, Seattle WA 98195-1640
U.S.A.

Abbreviated Biography:

D.Phil (1994) in the Dept Atmospheric, Oceanic & Planetary Physics, University of Oxford, England
1995-2001, at the Planetary Systems Branch, Space Science Division, NASA Ames Research Center, California.

with co-affiliations:

1996-1998 U.S. National Research Council
1998-2001 Center for the Study of Life in the Universe, SETI Institute, California

Taught Courses, 2002-4

Planetary Sciences and Astrobiology (ASTR 497C / ESS 490F) - autumn 2002
Astrobiology Disciplines (Co-taught) (ASTBIO 501) - autumn 2002
Planetary Atmospheres (ATMS 555) - winter 2003
Instruments and Observations in Atmospheric Sciences (ATMS 451) - spring 2003, spring 2004
Astrobiology Special Topics (ASTBIO 502): This year's theme: "The Evolution of Life from the Anaerobic to Aerobic World" - autumn 2003
Climate and Climate Change (ATMS 211) - winter 2004

Projects:

Principal Investigator for NASA Exobiology project: Evolution of Oxygen Atmospheres on Habitable Planets with Application to Life Detection and Advanced Life.

Co-Investigator for NASA Mars Data Analysis project: Condensate Clouds on Mars from Mars Global Surveyor.

Principal Investigator for NASA Mars Data Analysis project: Wind Processes and the Evolution of the Martian Surface Using Mars Global Surveyor and Mars Odyssey Data.

Principal Investigator for NASA Planetary Geology and Geophysics project: Aqueous Chemical Modeling of Sedimentation on Early Mars with Application to Surface-Atmosphere Evolution.

Co-Investigator on NASA Planetary Geology and Geophysics project: Aqueous Geochemical Models for Cold Planets


Co-Investigator on Matador (Mars Atmosphere and Dust in the Optical and Radio). We hope to compare the physics of dust devils on Earth with their larger counterparts on Mars. To the right is a photo of one the dust devils our team saw near the small town of Eloy, AZ, between Phoenix and Tucson. We measured dust devils using a mobile platform instrumented with wind, temperature, pressure, sound, electric field, and radio sensors.


Co-investigator on Phoenix, a Mars Lander (shown right), which will be NASA's first Mars Scout Program, mission, launching in 2007. Phoenix will investigate volatiles (especially water), organic molecules, and climate at a high-latitude site on Mars where NASA's Mars Odyssey orbiter has discovered evidence of ice in the soil.
In collaboration with Roger Buick, I have recently studied extreme climate swings at the Permian-Triassic (250 million years ago) when the largest mass extinction in animal history occurred. We inferred drastic climate change using carbon isotope data from the Blue Mountains, near Sydney, Australia. To the right is my view of Govett's Leap in the Blue Mountains in 2001. Triassic sandstone overlies Permian coal, with the boundary roughly at the tree line near the base of the waterfall. Charles Darwin looked out upon this very same scene in 1836. "Jan 18, 1836: Very early in the morning, I walked about three miles to see Govett's Leap...These valleys...are most remarkable. Great arm-like bays...penetrate the sandstone platform; on the other hand, the platform often sends promontories into the valleys, and even leaves in them great, almost insulated, masses." - C. R. Darwin, Chapter 19, The Voyage of the Beagle.

Co-Investigator on the Pascal Mission, a proposed NASA mission to place a network of 24 climate stations on Mars that monitor its climate for up to 10 Mars years (19 Earth years). Pascal was selected by NASA for pre-study in 2001.

Collaborator on Life in Extreme Environments project, studying the driest place on Earth: the Atacama desert in Chile.

Textbook

Along with Prof. Jim Kasting from Penn State University, I'm writing the following book, aimed at graduate students and researchers:

Atmospheric Evolution on Inhabited and Lifeless Worlds,
Cambridge University Press, to be published in 2007.

Selected Publications (mostly recent papers)

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, 2006, in press. [E-print]

A 1D numerical photochemical model is used to study the atmospheric photochemistry of oxygen, methane, and sulfur after the advent of oxygenic photosynthesis. We show that collapse of atmospheric methane in the late Archean to below 10 ppmv provides the best explanation of the disappearance of mass-independent fractionation in sulphur isotopes.

M. W. Claire, D.C. Catling and K. J. Zahnle, Biogeochemical modeling of the rise in atmospheric oxygen. Geobiology, vol. 4, 2006, in press. [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.

D.C. Catling, Comment on "A Hydrogen-rich Early Earth Atmosphere". Science 311, 38a, 2006. [E-print]

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.

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.

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.

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, and D. C. Catling, Oxidant enhancement in Martian dust devils and storms: Implications for life and habitability, Astrobiology , 6, 439-450, 2006.

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 how the level of dioxygen in the Earth's atmosphere has changed over the last 4 billion years and what caused the changes, to the best of our knowledge.

D C. Catling, Twin studies on Mars. Nature 436, 42-43, 2005. [E-print] Commentary on Mars rover results.

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, in press, 2006.

D. C. Catling, C. Leovy, Mars Atmosphere: History and Surface Interactions. In: L. McFadden, P. Weissman (eds.) Encyclopedia of the Solar System, to be published by Academic Press, 2006.[preprint]

D. C. Catling, Atmospheric Evolution of Mars. In: V. Gornitz (ed.) Encyclopedia of Paleoclimatology and Ancient Environments, to be published by Kluwer, 2006.[preprint]

R. Buick, J. A. Nicol, L. Watson, M. W. Claire, D. C. Catling, Multiple carbon isotope excursions at the Permian-Triassic boundary separate two mass extinctions, manuscript in preparation, 2006.

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.

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.

In this paper, 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.

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.

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 wierd atmosphere, which in turn allows life to flourish.

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.

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.

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]

In these field experiments we found that electric fields associated with dust devils exceeded 4 kV/m compared to a fair weather field of 70 V/m. On Mars, it is possible that electic fields approach the breakdown field strength for carbon dioxide. This dust devil work was motived by a National Research Council 2002 report entitled Safe on Mars: Precursor Measurements Necessary to Support Human Operations on the Martian Surface.

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]

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]

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.

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.

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]

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, 50, 915-927, 2002. [E-print]

D. Catling and K. Zahnle, Evolution of atmospheric oxygen, in Encyclopedia of Atmospheric Sciences (Ed. J. Holton, J. Curry, J. Pyle), Academic Press, 2002. [E-print]

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.

There were several discussions in the media of this research article. I like the following summary:

How Oxygen Came to our Atmosphere and What That Could Tell us About Other Worlds

View a 50 min seminar on this subject: The Rise of Oxygen, by David Catling (RealPlayer) given at the New York Center for Studies on the Origins of Life in 2001.

C. P. McKay, D. Catling, R. M. Haberle and N. G. Heavens, Extreme high temperatures in Death Valley, California, submitted to J. Appl. Meteor., 2003.

D. Catling, The Effect of Volcanoes on Atmospheric Chemistry and Climate over the Course of Earth History. Chapman Conference on Volcanism and the Earth's Atmosphere, Santorini, Greece, 2002.

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]

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]

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]

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.]

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]

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.

D. C. Catling. High sensitivity silicon capacitive sensors for measuring medium vacuum gas pressures, Sensors and Actuators, A64, 157-164, 1998. [E-print.]

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.

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.]

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.


The UW Department of Atmospheric Sciences is an internationally distinguished atmospheric sciences group with a variety of high quality research. Many well-known textbooks are written by departmental faculty . SO WHAT IS ASTROBIOLOGY ANYWAY? The UW Astrobiology Program allows graduate students to take courses and do some research outside their main discipline to broaden their scientific horizons. Astrobiology seeks to address three basic questions: (1) What's the history of life? (2) What's the future of life? (3) Is there life elsewhere? Today's atmosphere and biosphere are coupled chemical systems because all the important gases (O₂, N₂, CO₂, etc.) with the sole exception of argon are biologically mediated to some degree. There is still fundamental work to be done: there is no theory of "atmospheric composition" as such. Research on the chemical history of the atmosphere bears on the origin and history of life on Earth, as well as the future of life. It is also linked to the question of life elsewhere.