Guaciara M. Dos Santos
Research Project Scientist VI, KCCAMS/UCI Facility
Manager of the KCCAMS/UCI Facility
Biography
Dr. Guaciara M. dos Santos is a Research Project Scientist VI at the KCCAMS/UCI Facility in the Earth System Science Department at the University of California, Irvine. She earned her Ph.D. in Applied Nuclear Physics from Federal Fluminense University in Brazil in 1999 and her M.Sc. in Laser & Spectroscopy from the same institution in 1995. Santos completed postdoctoral research at the Australian National University from 1999 to 2001, focusing on accelerator mass spectrometry techniques.
Santos joined UCI in 2002 as an Associate Specialist and has served as Manager of the KCCAMS/UCI Facility since that time. Her research centers on radiocarbon analysis and its applications to understanding the global carbon cycle, atmospheric CO2 dynamics, and paleoclimate reconstruction. She has authored over 100 peer-reviewed articles in journals including Nature Physics, Radiocarbon, and Quaternary Geochronology. Santos has secured significant funding from the National Science Foundation, including a $3.3 million grant in 2021 for the acquisition of a MICADAS system. She received the UFF "Prata da Casa" Award in 2017 for outstanding academic achievement and has been invited to speak at numerous international conferences on radiocarbon dating and environmental applications.
At UCI, Santos oversees the operation of advanced accelerator mass spectrometry equipment and manages collaborative research projects with institutions worldwide. She has mentored over 50 students and research personnel, including undergraduate researchers, graduate students, and postdoctoral scholars. Santos serves on editorial boards and scientific advisory committees for major radiocarbon conferences and contributes to peer review for leading journals in her field. Her service includes roles on the International Scientific Advisory Board for radiocarbon conferences and membership on advisory panels for national AMS laboratories.
Return to topEducation
- Ph.D. in Apply Nuclear Physics, Federal Fluminense University, 1999
- M.Sc. in Laser & Spectroscopy, Federal Fluminense University, 1995
- Teaching Certification in General Physics, Federal Fluminense University, 1995
- B.Sc. in General physics, Federal Fluminense University, 1992
Distinctions
- UFF "Prata da Casa" Award for Outstanding Academic Achievement performance, Universidade Federal Fluminense (UFF), 2017
- LABEX OT-Med 2013, 2013
- NSF #MRI-2117634, National Science Foundation, 2021
- NSF #AGS/P2C2-1903687, National Science Foundation, 2019
- NSF #FY17/P2C22017, National Science Foundation, 2018
- NSF #EAR-1144888, National Science Foundation, 2012
- ANU Bridging Postdoctoral Fellow, Australia National University, 2001
- CNPq Postdoctoral Research Fellowship, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil, 1999
Areas of Expertise
- Accelerator Mass Spectrometry
- Radiocarbon Dating Applications
- Atmospheric Carbon Cycle
- Paleoclimate Sample Preparation
- Tree Ring Analysis
- Tropical Atmospheric Reconstruction
- Carbon Source Apportionment
- Phytolith Carbon Research
- MICADAS System Development
- Medieval Literature Translation
Recent Publications
- Guaciara M. Santos, Lucas G. Pereira, Ana C. Barbosa, Santiago Ancapichún, Peter van der Sleen, Pieter A. Zuidema, Peter Groenendijk, “Tropical Central African bomb radiocarbon reveals antiphase air-mass atmospheric fluxes and vegetation-growth relationships” (opens in new tab), Science of the Total Environment, vol. 989, 2025.
- Lucas Duy Nguyen, “Evaluations of standard measurement and procedural errors for tree ring 14C analysis through multivariable data comparisons”, Radiocarbon, 2024.
- June Nakachi Griffin, “FTIR wood compounds of multiple tropical tree species”, STOTEN, 2024.
- Christopher Leong, Anita Sumi Yayi Komatsu, Jazmine M. Jr. Renteria, “Improving a cellulose extraction protocol designed to all wood types and ¹⁴C ages”, QUAGEO, 2024.
- Santos, G.M., Nguyen, L.D., Griffin, J.N., Nathan de Oliveira Barreto, N.D., Ortega-Rodriguez, D.R., Barbosa, A.C., Gabriel Assis-Pereira, G., “Evaluating possible sources of error in tree-ring 14C data using multiple trees across South America” (opens in new tab), Radiocarbon, vol. 67, pp. 176-191, 2024.
- Harris, A.J.T., Santos, G.M., Malone, K.O., van der Meer, M.T.J., Riekenberg, P., Fernandes, R., “A long-term study of stable isotope ratios of fingernail keratin and amino acids in a mother-infant dyad” (opens in new tab), American Journal of Biological Anthropology, vol. 185, pp. e25021, 2024.
- Griffin, J.N., Santos, G.M., Nguyen, L.D., Rodriguez, D.R., Pereira, L.G., Jaén-Barrios, N., Assis-Pereira, G., de Oliveira Barreto, N., Brandes, A.F., Barbosa, A.C., Groenendijk, P., “Demystifying the tropics: FTIR characterization of pantropical woods and their α-cellulose extracts for past atmospheric 14C reconstructions” (opens in new tab), Science of The Total Environment, vol. 949, pp. 175010, 2024.
- Santos, G.M., Granato-Souza, D., Ancapichún, S., Oelkers, R., Haines, H.A., De Pol-Holz, R., Andreu-Hayles, L., Hua, Q., Barbosa, A.C., “A novel post-1950 CE atmospheric 14C record for the tropics using absolutely dated tree rings in the equatorial Amazon” (opens in new tab), Science of The Total Environment, vol. 918, pp. 170686, 2024.
- Biondi, F., Santos, G.M., Rodríguez, P.R., Sosa, P.A., “Longevity estimates of Canary palms and dragon trees by radiocarbon” (opens in new tab), Plants, vol. 13, no. 1, pp. 45, 2023.
- Santos, G.M., Leong, C.A., Seiler, M., Grootes, P.M., Svarva, H., Nadeau, M., “Radiocarbon step-combustion oxidation and FTIR analysis of Trondheim CaCO3 precipitates of atmospheric CO2 samples: further investigations and insights” (opens in new tab), Radiocarbon, vol. 66, pp. 1289-1301, 2023.
- Santos, G.M., Komatsu, A.S.Y., Jr. Renteria, J.M., Brandes, A.F.N., Leong, C.A., Collado-Fabbri, S., De Pol-Holz, R., “A universal approach to alpha-cellulose extraction for radiocarbon analysis of 14C-free to post-bomb ages” (opens in new tab), Quaternary Geochronology, vol. 74, pp. 101414, 2023.
- Rafael Perpétuo Albuquerque, “Tracking fossil fuel emissions from shipping activity deep in the amazon rainforest”, Environmental Research Journal, 2022.
- Santos G.M., Albuquerque R.P., Barros C.F., Ancapichún S., Oelkers R., Andreu-Hayles L., De Faria S.M., De Pol-Holz R., Brandes A.F.N., “High-precision 14C measurements of parenchyma-rich Hymenolobium petraeum tree species confirm bomb-peak atmospheric levels and reveal local fossil-fuel CO2 emissions in the Central Amazon” (opens in new tab), Environmental Research, vol. 214, 2022.
- Chiquetto, J.B., Leichsenring, A.R., Santos, G.M., “Socioeconomic conditions and fossil fuel CO2 in the Metropolitan Area of Rio de Janeiro” (opens in new tab), Urban Climate, vol. 43, pp. 101176, 2022.
- Santos, G.M., Rodriguez, D.R.O., Barreto, N.D.O., Assis-Pereira, G., Barbosa, A.C., Roig, F.A., Tomazello-Filho, M., “Growth Assessment of Native Tree Species from the Southwestern Brazilian Amazonia by Post-AD 1950 14C Analysis: Implications for Tropical Dendroclimatology Studies and Atmospheric 14C Reconstructions” (opens in new tab), Forests, vol. 12, no. 9, pp. 1177, 2021.
Most Cited Publications
- Santos, G.M., Southon, J., Griffin, S., Beaupre, S.R., Druffel, E.R., “Ultra small-mass 14C-AMS sample preparation and analysis at the KCCAMS Facility” (opens in new tab), Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms, vol. 259, pp. 293-302, 2007.
- Santos, G.M., Southon, J.R., Druffel-Rodriguez, K.C., Griffin, S., Mazon, M., “Magnesium perchlorate as an alternative water trap in AMS graphite sample preparation: A report on sample preparation at KCCAMS at the University of California, Irvine” (opens in new tab), Radiocarbon, vol. 46, pp. 165-173, 2004.
- Southon, J., Santos, G.M., Druffel-Rodriguez, K., Druffel, E., Trumbore, S., Xu, X. M., Griffin, S., Ali, S., Mazon, M., “The Keck Carbon Cycle AMS laboratory, University of California, Irvine: Initial operation and a background surprise” (opens in new tab), Radiocarbon, vol. 46, pp. 41-49, 2004.
- Santos, G.M., Moore, R.B., Southon, J.R., Griffin, S., Hinger, E., Zhang, D., “AMS 14C sample preparation at the KCCAMS/UCI Facility: status report and performance of small samples” (opens in new tab), Radiocarbon, vol. 49, no. 2, pp. 255-269, 2007.
- Lee, S.H., J. Gastaud, J.J. La Rosa, L. Liong Wee Knwong, P.P. Povinec, E. Wyse, L.K. Fifield, P.A. Hausladen, M.L. di Tada, G.M. Santos, “Analysis of Plutonium Isotopes in Marine Samples by Radiometric, ICP-MS and AMS Techniques” (opens in new tab), Journal of Radioanalytical and Nuclear Chemistry, vol. 248, no. 3, pp. 757-764, 2001.
- Santos, G.M., Southon J.R., Drenzek N.J., Ziolkowski L.A., Druffel E., Xu X., Zhang D., Trumbore S., Eglinton T.I., Hughen K.A., “Blank assessment for ultra-small samples: chemical extraction and separation vs. AMS” (opens in new tab), Radiocarbon, vol. 52, no. 3, pp. 1322-1335, 2010.
- Southon, J.R., Santos G.M., “Life with MC-SNICS Part II: recent ion source development at the Keck Carbon Cycle AMS Facility” (opens in new tab), Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms, vol. 259, pp. 88-93, 2007.
- Santos, G.M., Alexandre A., Coe H.G., Reyerson P.E., Southon J.R., De Carvalho C.N., “The Phytolith C puzzle: a tale of background determinations and accuracy tests” (opens in new tab), Radiocarbon, vol. 52, no. 1, pp. 113-128, 2010.
- Santos, Bird, Parenti, Fifield, Guidon, Hausladen, “A revised chronology of the lowest occupation layer of Pedra Furada Rock Shelter, Piauí, Brazil: The Pleistocene peopling of the Americas” (opens in new tab), Quaternary Science Reviews, vol. 22, pp. 2303-2310, 2003.
- Alexandre A., Basile-Doelsch I., Delhaye T., Borshneck D., Mazur J.C., Reyerson P., Santos G.M., “New highlights of phytolith structure and occluded carbon location: 3-X-ray microscopy and NanoSIMS results” (opens in new tab), Biogeosciences, vol. 12, pp. 863-873, 2015.
Contact Information
Website: https://sites.uci.edu/santos/
Email: gdossant@uci.edu
Phone: +1(949) 824-9851
Address: B321 Croul Hall, University of California, Irvine, CA 92697-3100
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Last updated on 7/24/2025.