Joe Sumesar-Rai

Joe Sumesar-Rai

Profile Display Name:

Joe Sumesar-Rai

E-mail Address:

Start Year

2018 (Cohort 5)

Research interests:

My key interests are palaeobiology and palaeoanthropology. I also have an interest in the application of geochemical methods to interpret past environmental and ecological conditions, particularly the use of stable isotopic proxies.

Hobbies and interests:

PhD Project
PhD Title

Can boron isotopes be used as a palaeodietary proxy?

Research Theme

Past Life and Environments

Primary Supervisor
Primary Institution


Secondary Supervisor
Secondary Institution



The stable isotope and trace element biogeochemistry of fossil tooth enamel has provided many insights into the dietary and behavioural ecology of extinct mammals, including early hominins, especially carbon isotopes as a proxy for C4 (savannah) grasses (Lee-Thorp et al., 2012). Boron isotopes in marine microfossils reflect the pH of the ocean environment, but little work on δ11B has been applied to the terrestrial realm.
Boron is an essential micronutrient in plants (O’Neill et al., 2004), and is digested and incorporated into the tissues of mammals. Measurements of δ11B can be obtained from tooth enamel (He et al., 2015), which is resistant to alteration during fossilisation.
Given the large mass difference in boron isotopes, δ11B fractionation may occur during the preparation or consumption of food. A broader understanding of the transfer and isotopic fractionation of boron within an ecosystem could facilitate the development of boron as a new and informative dietary proxy, with implications for our understanding of the dietary habits of primate and human ancestors.

Policy Impact
Background Reading
  • He, M. et al. (2015) ‘Determination of boron isotope ratios in tooth enamel by inductively coupled plasma mass spectrometry (ICP-MS) after matrix separation by ion exchange chromatography’, Journal of the Brazilian Chemical Society. Brazilian Chemical Society, 26(5), pp. 949–954. doi: 10.5935/0103-5053.20150056.
  • Lee-Thorp, J. et al. (2012) ‘Isotopic evidence for an early shift to C4 resources by Pliocene hominins in Chad’, Proceedings of the National Academy of Sciences, 109(50), pp. 20369–20372. doi: 10.1073/pnas.1204209109.
  • O’Neill, M. A. et al. (2004) ‘RHAMNOGALACTURONAN II: Structure and Function of a Borate Cross-Linked Cell Wall Pectic Polysaccharide’, Annual Review of Plant Biology, 55(1), pp. 109–139. doi: 10.1146/annurev.arplant.55.031903.141750
  • Grants and awards
    • Tim Newling Fieldwork Fund – Birkbeck, University of London


    Conferences and Workshops
    • Joint DTP Conference: Engaging Sustainability (September 2020). Poster: Boron isotopes in animal teeth can inform us about their diet.
    • The Micropalaeontological Society’s Microfossil Geochemistry Workshop (November 2020).
    • The Palaeontological Association Virtual Annual Meeting (December 2020).
    • GGRiP Conference (June 2021).
    • Goldschmidt Conference 2021 (July 2021).

    Social Links
    University Departmental Website:

    Personal Website:





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