Mark H. Thiemens

Mark Howard Thiemens is a distinguished professor and the John Doves Isaacs Endowed Chair in Natural Philosophy of Physical Sciences in the department of chemistry and biochemistry at the University of California San Diego.[1] He is best known for the discovery of a new physical chemical phenomena termed the mass independent isotope effect.[2]

Mark H. Thiemens
Born
St Louis, Mo, United States
EducationB.S. Univ. Miami,

M.S. Old Dominion University,

PhD. Florida State University Miami
Known forDiscovery of mass independent isotope chemistry and applications across nature in space and time, origin of life, climate change and physical chemistry of isotope effects
SpouseNasrin Marzban
ChildrenMaxwell Marzban Thiemens, Lillian Marzban Thiemens
AwardsGoldschmidt Medal

E.O. Lawrence Medal
Leonard Medal
Members of National Academy Science and American Academy Arts and Science

Asteroid named in honor: (7004) Markthiemens
Scientific career
FieldsPhysical chemistry of isotope effects,

Solar system origin and evolution,
Lunar and planetary science,
Climate change,

Origin and evolution of life
InstitutionsUniversity of California San Diego

His studies have crossed a broad range of topics including basic physical and quantum chemistry, solar system origin, tracking the origin and evolution of life on early earth; stratospheric chemistry, climate change and greenhouse gas identification, Mars atmospheric chemistry, past and future and isotope geochemistry. His work combines photochemical isotope studies, both laboratory and synchrotron based, field work in the South Pole,[3] Greenland Summit and the Tibetan Himalayas[4] for climate and geological sampling across China for early earth rock records.

His non-isotope work has included discovery of an unknown source of the greenhouse gas nitrous oxide that lead the global industrial elimination of all emissions, a major contribution to changing global climate change.[5] Thiemens has worked on developing new imaging techniques for space mission return samples[6][7][8][9][10][11][12] and detection of superconductivity in nature.[13]

Education

Thiemens earned his bachelor of Science degree from the University of Miami. His studies with isotope geochemist Cesare Emiliani, PhD student of Harold Urey and a co-discoverer of paleoclimate temperature determination stimulated his interests in isotopes. Thiemens received a MS from Old Dominion University and PhD from Florida State University for his research using stable isotopes and particle identification using the FSU Van de Graff accelerator. He moved to the University of Chicago at the Enrico Fermi Institute for Nuclear Studies (1977-1980) where he worked with Robert N. Clayton using lunar samples to track solar wind origin and evolution, meteorite cosmochemistry, and early atmospheric chemistry.

Career

Thiemens moved to the department of chemistry at the University of California San Diego in 1980, where he was hired as an assistant professor as a replacement for Hans Seuss and took over the laboratory of Nobel Laureate Harold Urey. He was promoted to full professor in 1989, and served as the chair of the department of chemistry and biochemistry from 1996-1999. He was the founding dean of the division of physical sciences and served from 1999-2016.

Research

Thiemens research at UCSD initiated after a re build of the Urey isotope ratio mass spectrometer to allow measurement of both oxygen isotope ratios (18O/16O, 17O/16O). His first publication as an assistant professor reported in Science the first mass independent isotope effect which occurred during ozone formation. This was the first demonstration of a chemical process that could alter isotope ratios in a manner independently of mass difference.[14] Most strikingly was that the pattern of mass independent and the 17O/16O,18O/16O variation varied equally and reproduced the same pattern observed in primitive inclusions of the Allende carbonaceous chondritic meteorite.[15] The underlying assumption for the inclusions anomaly deriving from a nucleosynthetic component was incorrect and new models for early solar system formation were needed and have evolved since. Much of Thiemens research has been dedicated to experimentally exploring the relevant fractionation processes that may account for the observations; including synchrotron photodissociation effects in CO.[16][17][18] The gas to particle formation process of the first solids in the nebula have also experimentally been shown to produce the mass independent anomaly.[19] Meteoritic material studies of Thiemens in sulfur isotopes have shown that sulfonic acids from chondritic meteorites have shown that photochemical processes have been important contributor to their molecular synthesis[20] as well other sulfur species.[21] To interpret mass independent isotope effects during photodissociation, Thiemens has worked in collaboration with Raphy Levine of Hebrew University[22][23] to interpret mass independent isotope effects during photodissociation and better explore the fundamental chemical physics of the processes. The understanding of the basis of the ozone effect has been extensively studied by Nobel Laureate Rudy Marcus and catalyzed deeper insight into the chemical physics.[24][25]

Thiemens has worked broadly on understanding the earth system. Thiemens and Trogler[26] identified a source of 10% of the increasing emissions of nitrous oxide, a greenhouse gas with a radiative forcing 200 times CO2 on a per molecules basis and a 100 year plus lifetime with unidentified sources. It was shown that the manufacture of adipic acid, used in nylon production is a globally important source. In the year post publication, a global inter industry consortium banded together to eliminate all N2O emissions, with far reaching climate impact.[5]

Thiemens at South Pole marker on expedition to dig snow pit for isotope record

Thiemens work in atmospheric chemistry has had extensive impact. The atmospheric chemistry of oxygen isotopes has been used to define atmospheric ozone surface reactions on Mars across billion-year time scales[27] and the oxygen isotopic carbonate record on Mars has been measured to deepen insight into reservoir mixing.[28][29] Terrestrial atmospheric carbonate aerosol oxygen isotopic measurements allow heterogenous reaction chemistry in both atmospheres to be resolved.[30] Mass independent sulfur isotopes in Mars meteorites were used to show ultra violet SO2 photochemical reactions in the past Martian atmosphere.[31]

The Mars sulfur observations lead to one of the most important applications of the isotope effects. In the present earth's atmosphere, the need for UV light to carry out SO2 photodissociation does not allow occurrence in today's lower atmosphere because of stratospheric ozone screening of UV light, but in a reduced oxygen atmosphere UV should pass through. Measurement of sulfur isotopes in the earths earliest rock record revealed that large and variable mass independent sulfur isotope effects occur in 33S/32S, 36S/32S ratios,[32] as observed in Mars meteorites and laboratory experiments.[33] The short atmospheric lifetime of SO2 photochemistry is produced only with lowered O2-O3 level. For first time, oxygen levels in the earliest earth could be determined.[34] The sulfur work is widely used to track the origin and evolution of life.

Present day sulfur isotopic anomalies in sulfate from Antarctic and Greenland ice have been used to determine the influence of massive volcanoes on the stratosphere.[35] Samples from a snow pit dug by Thiemens and colleagues have shown that there exist sources of sulfur chemistry that need to be included in studies of the atmosphere today and in the early earth.[36]

The inclusion of radiogenic 35S with the 4 stable sulfur isotopes have further enhanced mechanistic details of the contributors to the fractionation processes in the pre Cambrium era and today.[37] An atmospheric sulfur anomaly is observed in diamonds and uniquely tracks atmosphere-mantle mixing dynamics on billion-year time scales.[38]

Thiemens has used oxygen isotopes to study oxygen chemistry of the stratosphere and mesosphere using a rocket borne cryogenic whole air sampler.[39][40] The intersection of O(1D) from ozone photolysis exchange with CO2 and passes the isotopic anomaly to be used as a tracer. The small effect in the O2 is removed by the process of photosynthesis and respiration[41] and allows a new, highly sensitive way to quantify global primary productivity (GPP) in the world's oceans and, from oxygen trapped in ice cores across long time periods.

Using mass independent oxygen isotopes Thiemens and colleagues have applied them to further identify N2O sources. Thiemens developed the ability to measure naturally produced 35S (87-day half-life) to provide the first trans Pacific atmospheric Fukushima emissions and calculate the reactor neutronicity.[42][43] Recently the method determined melting rates of the Tibetan Himalayan glaciers, the source of drinking water of 40% of the Earth's population.[44] Thiemens has recently shown with his colleagues the first detection of superconductivity in nature, in this case in meteorites.[13]

Service

Besides his service as Chair and Dean, Thiemens has been active in external service:

  • Board of directors, San Diego State University Research Foundation, 2006-2009
  • City of San Diego Science Advisory Board (2002-2005)
  • San Diego Natural History Museum Board of Trustees (2001-2006)
  • San Diego Chamber of Commerce Environmental Advisory Board 1998-1999.
  • ECO AID Board of Advisors (1999-2002)
  • Science Advisory Board. Office of Trade and Business Development. San Diego (2002)
  • Kyoto Prize Symposium San Diego organizing committee, UCSD Lead. 2006-2016.
  • Council, The Meteoritical Society, 2008-2011.
  • Committee on the Significance of International Transport of Air Pollutants (2008-2009) National Research Council. (Global Sources of Local Pollution Report)
  • Understanding the Impact of Selling the Helium Reserve (2008-2009). National Research Council (Selling the Nations Helium Reserve Report) National Research Council
  • Planetary Protection Committee. Mars Sample Return (2008-2009). National Research Council (Assessment of Planetary Protection for Mars Sample Return Mission)
  • Committee for Planetary Protection Standards for Icy Bodies in the Outer Solar System (2011) National Research Council
  • Board on Energy and Environmental Systems 2009-2016. National Academy of Sciences.
  • Searching for Life Across Space and Time. (2016-2017). Space Science Board Requested study.
  • Space Sciences Board (2014–present). National Academy of Sciences
  • Executive committee, Space Sciences Board (2018—present) National Academy of Sciences.
  • Associate editor, Proceedings National Academy of Sciences, 2007 to present. National Academy of Sciences

Honors
  • Dreyfus Foundation Teacher- Scholar Award (1986)
  • Alexander Von Humboldt Fellows Award (1990)
  • Alexander Von Humboldt Award (1993)
  • Elected, Fellow of the Meteoritical Society (1996)
  • Ernest O. Lawrence Medal, Department of Energy (1998)
  • Chancellors Associates Endowed Chair (1999–present)
  • American Chemical Society (San Diego) Distinguished Scientist of the year (2002)
  • Elected, Fellow, American Academy of Arts and Sciences (2002)
  • Distinguished Alumni Award, Old Dominion University (2003)
  • Press Club Headliner of the Year 2002 (2003)
  • Selected, San Diego City Beat, 33 People to Watch in 2003 (2003)
  • Creative Catalyst Award, UCSD-TV (2003)
  • Elected, Phi Beta Kappa (2005)
  • Elected, National Academy of Sciences (2006)
  • Minor Planet Named in his Honor: Asteroid (7004) Markthiemens. International Astronomical Union (2006).[45]
  • Elected, Fellow American Geophysical Union (2006).
  • Elected, Fellow, Geochemical Society (2007)
  • Elected, Fellow, European Association for Geochemistry (2007)
  • Graduate Made Good, Distinguished Alumni, Omega Delta Kappa Honor Society, Florida State University (2007)
  • V.M. Goldschmidt Medal; The Geochemical Society. Awarded in Davos, Switzerland (2009)
  • Selected one of 100 Distinguished Graduates in 100 years of Florida State University History (2010).
  • Cozzarelli Prize, U.S. National Academy of Sciences for outstanding paper in Physical Sciences in the Proceedings of the National Academy of Sciences (2011).
  • Elected Fellow, American Association Arts and Sciences (2013).
  • Albert Einstein Professor, Chinese Academy of Sciences (2014).
  • Leonard Medal of the Meteoritical Society (2017)
  • Miller Visiting Professor, University California Berkeley (2017)
  • Gauss Professorship, Göttingen Academy of Sciences, Germany (2017)
  • Gauss Professorship, Göttingen Academy of Sciences, Germany (2020)

References
  1. "Thiemens, Mark". Chemistry and Biochemistry. 1980-01-01. Retrieved 2023-07-03.
  2. "Mark Thiemens".
  3. "In The Pits: Scientists Dig Through South Pole Snow For Climate Clues" (Press release). UC San Diego. March 1, 2013. Retrieved May 22, 2020.
  4. "Scientists Go to Great Heights to Understand Changes in Earth's Atmosphere" (Press release). UC San Diego. June 18, 2018. Retrieved May 22, 2020.
  5. "SCIENCE WATCH; The Nylon Effect". The New York Times. 26 February 1991.
  6. "Nanoscale infrared spectroscopy as a non-destructive probe of extraterrestrial samples".
  7. Dai, S.; Fei, Z.; Ma, Q.; Rodin, A. S.; Wagner, M.; McLeod, A. S.; Liu, M. K.; Gannett, W.; Regan, W.; Watanabe, K.; Taniguchi, T.; Thiemens, M.; Dominguez, G.; Neto, A. H. Castro; Zettl, A.; Keilmann, F.; Jarillo-Herrero, P.; Fogler, M. M.; Basov, D. N. (7 March 2014). "Tunable Phonon Polaritons in Atomically Thin van der Waals Crystals of Boron Nitride". Science. 343 (6175): 1125–1129. Bibcode:2014Sci...343.1125D. doi:10.1126/science.1246833. hdl:1721.1/90317. PMID 24604197. S2CID 4253950.
  8. Fei, Z.; Rodin, A. S.; Andreev, G. O.; Bao, W.; McLeod, A. S.; Wagner, M.; Zhang, L. M.; Zhao, Z.; Thiemens, M.; Dominguez, G.; Fogler, M. M.; Neto, A. H. Castro; Lau, C. N.; Keilmann, F.; Basov, D. N. (July 2012). "Gate-tuning of graphene plasmons revealed by infrared nano-imaging". Nature. 487 (7405): 82–85. arXiv:1202.4993. Bibcode:2012Natur.487...82F. doi:10.1038/nature11253. PMID 22722866. S2CID 4348703.
  9. Dominguez, Gerardo; Mcleod, A. S.; Gainsforth, Zack; Kelly, P.; Bechtel, Hans A.; Keilmann, Fritz; Westphal, Andrew; Thiemens, Mark; Basov, D. N. (9 December 2014). "Nanoscale infrared spectroscopy as a non-destructive probe of extraterrestrial samples". Nature Communications. 5 (1): 5445. Bibcode:2014NatCo...5.5445D. doi:10.1038/ncomms6445. PMID 25487365.
  10. Dai, S.; Ma, Q.; Andersen, T.; Mcleod, A. S.; Fei, Z.; Liu, M. K.; Wagner, M.; Watanabe, K.; Taniguchi, T.; Thiemens, M.; Keilmann, F.; Jarillo-Herrero, P.; Fogler, M. M.; Basov, D. N. (22 April 2015). "Subdiffractional focusing and guiding of polaritonic rays in a natural hyperbolic material". Nature Communications. 6 (1): 6963. arXiv:1502.04094. Bibcode:2015NatCo...6.6963D. doi:10.1038/ncomms7963. PMC 4421822. PMID 25902364.
  11. Fei, Z.; Rodin, A. S.; Gannett, W.; Dai, S.; Regan, W.; Wagner, M.; Liu, M. K.; McLeod, A. S.; Dominguez, G.; Thiemens, M.; Castro Neto, Antonio H.; Keilmann, F.; Zettl, A.; Hillenbrand, R.; Fogler, M. M.; Basov, D. N. (November 2013). "Electronic and plasmonic phenomena at graphene grain boundaries". Nature Nanotechnology. 8 (11): 821–825. arXiv:1311.6827. Bibcode:2013NatNa...8..821F. doi:10.1038/nnano.2013.197. PMID 24122082. S2CID 494891.
  12. Dai, S.; Ma, Q.; Liu, M. K.; Andersen, T.; Fei, Z.; Goldflam, M. D.; Wagner, M.; Watanabe, K.; Taniguchi, T.; Thiemens, M.; Keilmann, F.; Janssen, G. C. a. M.; Zhu, S.-E.; Jarillo-Herrero, P.; Fogler, M. M.; Basov, D. N. (August 2015). "Graphene on hexagonal boron nitride as a tunable hyperbolic metamaterial". Nature Nanotechnology. 10 (8): 682–686. arXiv:1501.06956. Bibcode:2015NatNa..10..682D. doi:10.1038/nnano.2015.131. PMID 26098228. S2CID 205452562.
  13. Wampler, James; Thiemens, Mark; Cheng, Shaobo; Zhu, Yimei; Schuller, Ivan K. (7 April 2020). "Superconductivity found in meteorites". Proceedings of the National Academy of Sciences. 117 (14): 7645–7649. Bibcode:2020PNAS..117.7645W. doi:10.1073/pnas.1918056117. PMC 7148572. PMID 32205433.
  14. Thiemens, M. H.; Heidenreich, J. E. (4 March 1983). "The Mass-Independent Fractionation of Oxygen: A Novel Isotope Effect and Its Possible Cosmochemical Implications". Science. 219 (4588): 1073–1075. Bibcode:1983Sci...219.1073T. doi:10.1126/science.219.4588.1073. PMID 17811750. S2CID 26466899.
  15. Clayton, R. N.; Grossman, L.; Mayeda, T. K. (2 November 1973). "A Component of Primitive Nuclear Composition in Carbonaceous Meteorites". Science. 182 (4111): 485–488. Bibcode:1973Sci...182..485C. doi:10.1126/science.182.4111.485. PMID 17832468. S2CID 22386977.
  16. "New Clues to Oxygen at the Origin of the Solar System".
  17. Chakraborty, S.; Ahmed, M.; Jackson, T. L.; Thiemens, M. H. (5 September 2008). "Experimental Test of Self-Shielding in Vacuum Ultraviolet Photodissociation of CO". Science. 321 (5894): 1328–1331. Bibcode:2008Sci...321.1328C. doi:10.1126/science.1159178. PMID 18772432. S2CID 713105.
  18. Chakraborty, Subrata; Davis, Ryan D.; Ahmed, Musahid; Jackson, Teresa L.; Thiemens, Mark H. (14 July 2012). "Oxygen isotope fractionation in the vacuum ultraviolet photodissociation of carbon monoxide: Wavelength, pressure, and temperature dependency". The Journal of Chemical Physics. 137 (2): 024309. Bibcode:2012JChPh.137b4309C. doi:10.1063/1.4730911. PMID 22803538. S2CID 7312120.
  19. "Scientists solve mystery of odd patterns of oxygen in solar system's earliest rocks".
  20. Cooper, George W.; Thiemens, Mark H.; Jackson, Teresa L.; Chang, Sherwood (22 August 1997). "Sulfur and Hydrogen Isotope Anomalies in Meteorite Sulfonic Acids". Science. 277 (5329): 1072–1074. Bibcode:1997Sci...277.1072C. doi:10.1126/science.277.5329.1072. hdl:2060/19980038124. PMID 9262469.
  21. Rai, V. K. (12 August 2005). "Photochemical Mass-Independent Sulfur Isotopes in Achondritic Meteorites". Science. 309 (5737): 1062–1065. Bibcode:2005Sci...309.1062R. doi:10.1126/science.1112954. PMID 16099982. S2CID 26306652.
  22. Muskatel, B. H.; Remacle, F.; Thiemens, M. H.; Levine, R. D. (24 March 2011). "On the strong and selective isotope effect in the UV excitation of N2 with implications toward the nebula and Martian atmosphere". Proceedings of the National Academy of Sciences. 108 (15): 6020–6025. Bibcode:2011PNAS..108.6020M. doi:10.1073/pnas.1102767108. PMC 3076819. PMID 21441106.
  23. Chakraborty, S.; Muskatel, B. H.; Jackson, T. L.; Ahmed, M.; Levine, R. D.; Thiemens, M. H. (29 September 2014). "Massive isotopic effect in vacuum UV photodissociation of N2 and implications for meteorite data". Proceedings of the National Academy of Sciences. 111 (41): 14704–14709. Bibcode:2014PNAS..11114704C. doi:10.1073/pnas.1410440111. PMC 4205658. PMID 25267643.
  24. Gao, Y. Q. (31 May 2001). "Strange and Unconventional Isotope Effects in Ozone Formation". Science. 293 (5528): 259–263. Bibcode:2001Sci...293..259G. doi:10.1126/science.1058528. PMID 11387441. S2CID 867229.
  25. "Rudolph A. (Rudy) Marcus | Division of Chemistry and Chemical Engineering".
  26. Thiemens, M. H.; Trogler, W. C. (22 February 1991). "Nylon Production: An Unknown Source of Atmospheric Nitrous Oxide". Science. 251 (4996): 932–934. Bibcode:1991Sci...251..932T. doi:10.1126/science.251.4996.932. PMID 17847387. S2CID 22090514.
  27. Farquhar, J. (5 June 1998). "Atmosphere-Surface Interactions on Mars: 17O Measurements of Carbonate from ALH 84001". Science. 280 (5369): 1580–1582. doi:10.1126/science.280.5369.1580. PMID 9616116.
  28. "New chemical analysis of ancient Martian meteorite provides clues to planet's history of habitability".
  29. Shaheen, Robina; Niles, Paul B.; Chong, Kenneth; Corrigan, Catherine M.; Thiemens, Mark H. (13 January 2015). "Carbonate formation events in ALH 84001 trace the evolution of the Martian atmosphere". Proceedings of the National Academy of Sciences. 112 (2): 336–341. Bibcode:2015PNAS..112..336S. doi:10.1073/pnas.1315615112. PMC 4299197. PMID 25535348.
  30. Shaheen, R.; Abramian, A.; Horn, J.; Dominguez, G.; Sullivan, R.; Thiemens, M. H. (8 November 2010). "Detection of oxygen isotopic anomaly in terrestrial atmospheric carbonates and its implications to Mars". Proceedings of the National Academy of Sciences. 107 (47): 20213–20218. Bibcode:2010PNAS..10720213S. doi:10.1073/pnas.1014399107. PMC 2996665. PMID 21059939.
  31. Farquhar, James; Savarino, Joel; Jackson, Terri L.; Thiemens, Mark H. (March 2000). "Evidence of atmospheric sulphur in the martian regolith from sulphur isotopes in meteorites". Nature. 404 (6773): 50–52. Bibcode:2000Natur.404...50F. doi:10.1038/35003517. PMID 10716436. S2CID 731902.
  32. Farquhar, J. (4 August 2000). "Atmospheric Influence of Earth's Earliest Sulfur Cycle". Science. 289 (5480): 756–758. Bibcode:2000Sci...289..756F. doi:10.1126/science.289.5480.756. PMID 10926533.
  33. Farquhar, James; Savarino, Joel; Airieau, Sabine; Thiemens, Mark H. (25 December 2001). "Observation of wavelength-sensitive mass-independent sulfur isotope effects during SO photolysis: Implications for the early atmosphere". Journal of Geophysical Research: Planets. 106 (E12): 32829–32839. Bibcode:2001JGR...10632829F. doi:10.1029/2000JE001437.
  34. Great Oxidation Event
  35. Baroni, M.; Thiemens, M. H.; Delmas, R. J.; Savarino, J. (5 January 2007). "Mass-Independent Sulfur Isotopic Compositions in Stratospheric Volcanic Eruptions". Science. 315 (5808): 84–87. Bibcode:2007Sci...315...84B. doi:10.1126/science.1131754. PMID 17204647. S2CID 40342760.
  36. Shaheen, R.; Abaunza, M. M.; Jackson, T. L.; McCabe, J.; Savarino, J.; Thiemens, M. H. (4 August 2014). "Large sulfur-isotope anomaly in nonvolcanic sulfate aerosol and its implications for the Archean atmosphere". Proceedings of the National Academy of Sciences. 111 (33): 11979–11983. Bibcode:2014PNAS..11111979S. doi:10.1073/pnas.1406315111. PMC 4143030. PMID 25092338.
  37. Lin, Mang; Zhang, Xiaolin; Li, Menghan; Xu, Yilun; Zhang, Zhisheng; Tao, Jun; Su, Binbin; Liu, Lanzhong; Shen, Yanan; Thiemens, Mark H. (21 August 2018). "Five-S-isotope evidence of two distinct mass-independent sulfur isotope effects and implications for the modern and Archean atmospheres". Proceedings of the National Academy of Sciences. 115 (34): 8541–8546. Bibcode:2018PNAS..115.8541L. doi:10.1073/pnas.1803420115. PMC 6112696. PMID 30082380.
  38. Farquhar, J. (20 December 2002). "Mass-Independent Sulfur of Inclusions in Diamond and Sulfur Recycling on Early Earth". Science. 298 (5602): 2369–2372. Bibcode:2002Sci...298.2369F. doi:10.1126/science.1078617. PMID 12493909. S2CID 22498879.
  39. "Air Samples Show Ozone Depletion May Have Other Causes Than Fluorocarbons". Associated Press.
  40. Thiemens, M. H.; Jackson, T.; Zipf, E. C.; Erdman, P. W.; van Egmond, C. (10 November 1995). "Carbon Dioxide and Oxygen Isotope Anomalies in the Mesosphere and Stratosphere". Science. 270 (5238): 969–972. Bibcode:1995Sci...270..969T. doi:10.1126/science.270.5238.969. S2CID 98076813.
  41. Luz, Boaz; Barkan, Eugeni; Bender, Michael L.; Thiemens, Mark H.; Boering, Kristie A. (August 1999). "Triple-isotope composition of atmospheric oxygen as a tracer of biosphere productivity". Nature. 400 (6744): 547–550. Bibcode:1999Natur.400..547L. doi:10.1038/22987. S2CID 4345679.
  42. "Tracking the radiation released from Fukushima | Earth | EarthSky". 15 August 2011.
  43. Priyadarshi, A.; Dominguez, G.; Thiemens, M. H. (15 August 2011). "Evidence of neutron leakage at the Fukushima nuclear plant from measurements of radioactive 35S in California". Proceedings of the National Academy of Sciences. 108 (35): 14422–14425. Bibcode:2011PNAS..10814422P. doi:10.1073/pnas.1109449108. PMC 3167508. PMID 21844372.
  44. Lin, Mang; Wang, Kun; Kang, Shichang; Thiemens, Mark H. (15 March 2017). "Simple Method for High-Sensitivity Determination of Cosmogenic 35S in Snow and Water Samples Collected from Remote Regions". Analytical Chemistry. 89 (7): 4116–4123. doi:10.1021/acs.analchem.6b05066. PMID 28256822.
  45. "Minor Planet Named for UCSD Science Dean". Photonics.com. 2006-08-22. Retrieved 2020-07-31.
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