Max Planck Gesellschaft



The goal of 14Constraint is to enhance the availability and use of radiocarbon data as constraints for process-based understanding of the age distribution of carbon in and respired by soils and ecosystems. A team of researchers who is envisioned who will (1) work collaboratively with others on building an open community database of 14C data; (2) fill gaps in data and understanding by making new radiocarbon measurements in soil and respired CO2, (3) use models to interpret data for improving models of soil C cycling and (4) produce global data products for comparison with models.

The 14Constraint Team

PIs: Susan Trumbore, Carlos Sierra, Marion Schrumpf
Technical support: Kerstin Lohse, Jessica Heublein, Iris Kuhlmann, The Jena 14C analysis Facility
Researchers: Alison Hoyt, Valerie Schwab, Jan Muhr
PhD students: Jeffrey Beem-Miller, Shane Stoner
Collaborating researchers
UC Irvine: Jim Randerson, Xiaomei Xu, Yujie He, Paul Levine, Zheng Shi, Steve Allison
Lawrence Berkeley Lab: Margaret Torn, Bill Riley

Radiocarbon Short Course in Irvine - August 2019

ISRaD - the International Soil Radiocarbon Database

See the ISRad web page

Also see the published paper in Earth Science Data

Powell Center Meeting Participants

Recent events

  • ISRaD/Powell Center Soil Radiocarbon Workshop at LBL, Dec 5th - 8th, 2019 (organized by A. Hoyt and K
  • Urugay - Max-Planck Research Group to collaborate on Radiocarbon
  • Carlos Sierra hosts a group working on incubation database
  • ISRaD manuscript submitted to Earth and Science Data Discussions
  • EGU meeting April 2019 -- presentation of ISRaD and related content
  • SSSA meeting in San Diego, January 2019
  • AGU meeting December 2018
  • Hackathon in Jena on November 15,16 and 17 2018 to get everything in shape before AGU
  • Sue, Alison and Jeff participated in the Powell Center soil carbon meeting in Fort Collins Colorado, October 8-12, 2018 and discussued collaborative activities for ISRAD.
  • 14Constraint is hosting a “hack-a-thon” the 10-17 September with colleagues from the Powell center to work on the International Soil Radiocarbon Database (IsRad) and the publication announcing it.
  • Alison Hoyt co-convening a session at AGU: B087: Timescales of Carbon Cycling in Soils: Observations, Data Synthesis and Modeling
  • June 2018 Jeff Beem-Miller gives a talk on the Radiocarbon data base at the Radiocarbon meeting in Trondheim (From Fractions to Fluxes: The International Soil Radiocarbon Database (ISRaD)
  • May-July 2018 - Visit by istván Fekete (University of Nyiregyhaza, Hungary) funded by ERC
  • March 2018 - Susan give a talk at the INRA Symposium on Earth System Function and Climate Change
  • December 2017 AGU meeting and ICSN Hackathon
  • November 2017 Powell Center Database workshop with Corey Lawrence
  • September 2017 Radiocarbon short course
  • August-October 2017 Visit by Visit by Kateřina Jandová (Charles University, Prague, Czech Republic)
  • July- August 2017 Visit by Suzanne Pierre (Cornell University, New York, USA)
  • July 2017 Installation of the new Micadas AMS system at BGC


1Heckman, K., Hicks Pries, C. E., Lawrence, C. R., Rasmussen, C., Crow, S. E., Hoyt, A. M., von Fromm, S. F., Shi, Z., Stoner, S., McGrath, C., Beem-Miller, J., Berhe, A. A., Blankinship, J. C., Keiluweit, M., Marín-Spiotta, E., Monroe, J. G., Plante, A. F., Schimel, J., Sierra, C., Thompson, A., Wagai, R. (2022). Beyond bulk: Density fractions explain heterogeneity in global soil carbon abundance and persistence. Global Change Biology, 28(3), 1178-1196. doi:10.1111/gcb.16023.
2Tilmes, S., Visioni, D., Jones, A., Haywood, J., Seferian, R., Nabat, P., Boucher, O., Bednarz, E. M., Niemeier, U. (2022). Stratospheric ozone response to sulfate aerosol and solar dimming climate interventions based on the G6 Geoengineering Model Intercomparison Project (GeoMIP) simulations. Atmospheric Chemistry and Physics, 22(7), 4557-4579. doi:10.5194/acp-22-4557-2022.
3Overholt, W. A., Trumbore, S. E., Xu, X., Bornemann, T. L. V., Probst, A. J., Krüger, M., Herrmann, M., Thamdrup, B., Bristow, L. A., Taubert, M., Schwab, V. F., Hölzer, M., Marz, M., Küsel, K. (2022). Carbon fixation rates in groundwater similar to those in oligotrophic marine systems. Nature Geoscience, 15, 561-567. doi:10.1038/s41561-022-00968-5.
4von Fromm, S. F., Hoyt, A. M., Lange, M., Acquah, G. E., Aynekulu, E., Berhe, A. A., Haefele, S. M., McGrath, S. P., Shepherd, K. D., Sila, A. M., Six, J., Towett, E. K., Trumbore, S. E., Vågen, T.-G., Weullow, E., Winowiecki, L. A., Doetterl, S. (2021). Continental-scale controls on soil organic carbon across sub-Saharan Africa. Soil, 7(1), 305-332. doi:10.5194/soil-7-305-2021.
5Bukombe, B., Fiener, P., Hoyt, A. M., Kidinda, L. K., Doetterl, S. (2021). Heterotrophic soil respiration and carbon cycling in geochemically distinct African tropical forest soils. Soil, 7(2), 639-659. doi:10.5194/soil-7-639-2021.
6Stoner, S., Hoyt, A. M., Trumbore, S. E., Sierra, C., Schrumpf, M., Doetterl, S., Baisden, W. T., Schipper, L. A. (2021). Soil organic matter turnover rates increase to match increased inputs in grazed grasslands. Biogeochemistry, 156, 145-160. doi:10.1007/s10533-021-00838-z.
7Hilman, B., Muhr, J., Helm, J., Kuhlmann, I., Schulze, E. D., Trumbore, S. E. (2021). The size and the age of the metabolically active carbon in tree roots. Plant, Cell and Environment, 44(8), 2522-2535. doi:10.1111/pce.14124.
8Fekete, I., Berki, I., Lajtha, K., Trumbore, S. E., Francioso, O., Gioacchini, P., Montecchio, D., Várbíró, G., Béni, Á., Makádi, M., Demeter, I., Madarász, B., Juhos, K., Kotroczó, Z. (2021). How will a drier climate change carbon sequestration in soils of the deciduous forests of Central Europe? Biogeochemistry, 152, 13-32. doi:10.1007/s10533-020-00728-w.
9Beem-Miller, J., Schrumpf, M., Hoyt, A. M., Guggenberger, G., Trumbore, S. E. (2021). Impacts of drying and rewetting on the radiocarbon signature of respired CO2 and implications for incubating archived soils. Journal of Geophysical Research: Biogeosciences, 126(9): e2020JG006119. doi:10.1029/2020JG006119.
10Schädel, C., Beem-Miller, J., Rad, M. A., Crow, S. E., Pries, C. H., Ernakovich, J., Hoyt, A. M., Plante, A., Stoner, S., Treat, C. C., Sierra, C. (2020). Decomposability of soil organic matter over time: the Soil Incubation Database (SIDb, version 1.0) and guidance for incubation procedures. Earth System Science Data, 12(3), 1511-1524. doi:10.5194/essd-12-1511-2020.
11Estop-Aragonés, C., Olefeldt, D., Abbott, B. W., Chanton, J. P., Czimczik, C. I., Dean, J. F., Egan, J. E., Gandois, L., Garnett, M. H., Hartley, I. P., Hoyt, A. M., Lupascu, M., Natali, S. M., O’Donnell, J. A., Raymond, P. A., Tanentzap, A. J., Tank, S. E., Schuur, E. A. G., Turetsky, M., Anthony, K. W. (2020). Assessing the potential for mobilization of old soil carbon after permafrost thaw: A synthesis of 14C measurements from the northern permafrost region. Global Biogeochemical Cycles, 34(9): e2020GB006672. doi:10.1029/2020GB006672.
12Lawrence, C. R., Beem-Miller, J., Hoyt, A. M., Monroe, G., Sierra, C. A., Stoner, S., Heckman, K., Blankinship, J. C., Crow, S. E., McNicol, G., Trumbore, S. E., Levine, P. A., Vindušková, O., Todd-Brown, K., Rasmussen, C., Pries, C. E. H., Schädel, C., McFarlane, K., Doetterl, S., Hatté, C., He, Y., Treat, C., Harden, J. W., Torn, M. S., Estop-Aragonés, C., Berhe, A. A., Keiluweit, M., Kuhnen, Á. D. R., Marin-Spiotta, E., Plante, A. F., Thomson, A., Shi, Z., Schimel, J. P., Vaughn, L. J. S., von Fromm, S. F., Wagai, R. (2020). An open-source database for the synthesis of soil radiocarbon data: International Soil Radiocarbon Database (ISRaD) version 1.0. Earth System Science Data, 12(1), 61-76. doi:10.5194/essd-12-61-2020.
13Shi, Z., Allison, S. D., He, Y., Levine, P. A., Hoyt, A. M., Beem-Miller, J., Zhu, Q., Wieder, W. R., Trumbore, S. E., Randerson, J. T. (2020). The age distribution of global soil carbon inferred from radiocarbon measurements. Nature Geoscience, 13, 555-559. doi:10.1038/s41561-020-0596-z.
14Metzler, H., Zhu, Q., Riley, W., Hoyt, A. M., Müller, M., Sierra, C. (2020). Mathematical reconstruction of land carbon models from their numerical output: computing soil radiocarbon from 12C dynamics. Journal of Advances in Modeling Earth Systems, 12(1): e2019MS001776. doi:10.1029/2019MS001776.
15Gandois, L., Hoyt, A. M., Hatté, C., Jeanneau, L., Teisserenc, R., Liotaud, M., Tananaev, N. (2019). Contribution of peatland permafrost to dissolved organic matter along a thaw gradient in North Siberia. Environmental Science & Technology, 53(24), 14165-14174. doi:10.1021/acs.est.9b03735.
16Chen, J., Zhu, Q., Riley, W. J., He, Y., Randerson, J. T., Trumbore, S. E. (2019). Comparison with global soil radiocarbon observations indicates needed carbon cycle improvements in the E3SM land model. Journal of Geophysical Research: Biogeosciences, 124(5), 1098-1114. doi:10.1029/2018JG004795.
17D'Andrea, E., Rezaie, N., Battistelli, A., Gavrichkova, O., Kuhlmann, I., Matteucci, G., Moscatello, S., Proietti, S., Scartazza, A., Trumbore, S. E., Muhr, J. (2019). Winter's bite: beech trees survive complete defoliation due to spring late-frost damage by mobilizing old C reserves. New Phytologist, 224(2), 625-631. doi:10.1111/nph.16047.
18Drake, T. W., Oost, K. V., Barthel, M., Bauters, M., Hoyt, A. M., Podgorski, D. C., Six, J., Boeckx, P., Trumbore, S. E., Ntaboba, L. C., Spencer, R. G. M. (2019). Mobilization of aged and biolabile soil carbon by tropical deforestation. Nature Geoscience, 12(7), 541-546. doi:10.1038/s41561-019-0384-9.
19Malhotra, A., Todd-Brown, K., Nave, L. E., Batjes, N. H., Holmquist, J. R., Hoyt, A. M., Iversen, C. M., Jackson, R. B., Lajtha, K., Lawrence, C., Vinduskova, O., Wieder, W., Williams, M., Hugelius, G., Harden, J. (2019). The landscape of soil carbon data: emerging questions, synergies and databases. Progress in Physical Geography: Earth and Environment, 43(5), 707-719. doi:10.1177/0309133319873309.
20Schwab, V. F., Nowak, M., Elder, C. D., Trumbore, S. E., Xu, X., Gleixner, G., Lehmann, R., Pohnert, G., Muhr, J., Kuesel, K., Totsche, K. U. (2019). 14C-free carbon is a major contributor to cellular biomass in geochemically distinct groundwater of shallow sedimentary bedrock aquifers. Water Resources Research, 55(3), 2104-2121. doi:10.1029/2017WR022067.
21Sierra, C. A., Hoyt, A. M., He, Y., Trumbore, S. E. (2018). Soil organic matter persistence as a stochastic process: age and transit time distributions of carbon in soils. Global Biogeochemical Cycles, 32(10), 1574-1588. doi:10.1029/2018GB005950.
22Nagy, R. C., Porder, S., Brando, P., Davidson, E. A., Figueira, A. M. e. S., Neill, C., Riskin, S., Trumbore, S. E. (2018). Soil carbon dynamics in soybean cropland and forests in Mato Grosso, Brazil. Journal of Geophysical Research: Biogeosciences, 123(1), 18-31. doi:10.1002/2017JG004269.

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