Supervisors

Dr Mary Gagen, Swansea University

Dr Iain Robertson, Swansea University

Prof Rory Walsh, Swansea University 

Project and aims 

The El Niño-Southern Oscillation (ENSO) causes significant climatic anomalies and changes in storm trajectories over much of the tropics and subtropics. At Sabah (northern Borneo), severe droughts occur during ENSO years (Walsh and Newberry, 1999). As meteorological records are very limited, indirect records are required to reconstruct past ENSO events (Robertson et al., 2004). This aim of the studentship is to exploit potential climate proxy records from long lived tropical trees to develop reconstructions of past climate, including the history of El Niño-Southern Oscillation (ENSO) events, back into the pre-instrumental era.

Stable isotope and blue reflectance values will be determined from trees growing at one of several potential sites on Borneo (Danum Valley, the Maliau Basin or the Imbak Canyon). At the University of Wales Swansea, ring widths will be measured using a measuring stage and binocular microscope. Cross-dating of individual time series will ensure that there is absolute confidence in the integrity of dates. With tropical trees, this is far from a trivial task! Initial chronologies will be confirmed by wiggle-matching radiocarbon dates (Robertson et al., 2004). Once completed, annually-resolved isotope values will be measured on individual trees rather than pooled or bulk samples to enable errors to be determined. Research at Danum will be linked to the Royal Society SE Asia Rainforest Research Programme. 

The student will join the Tree Ring research group at Swansea and will be trained in laboratory and data analysis techniques. Analytical facilities at the Swansea Stable Isotope Laboratory include a PDZ Europa 20/20 stable isotope ratio mass spectrometer and ANCA GSL elemental analyzer. Through recent investment the School of Environment and Society offers a suite of well equipped laboratories and a vibrant research environment through the interdisciplinary Institute for Environmental Sustainability. 

Applicant requirements

We are looking for a candidate with at least an upper second class degree in geography, botany, chemistry or a related discipline. The student will be based at the Swansea University and will spend several weeks collecting samples from Borneo over two field seasons. The successful candidate will be actively involved in experimental design, fieldwork, analysis and the interpretation of results. For further details, please contact Dr Iain Robertson (i.robertson@swansea.ac.uk) or Dr Mary Gagen (m.h.gagen@swansea.ac.uk)

Funding

This project is eligible for competitive funding through NERC studentships awarded to the Department. Other funding opportunities are available and self-funded students are always welcome. Contact your potential supervisor for advice and details of how to apply. The closing date for applications to NERC studentships is 18 March 2011.  

References

McCarroll D., Loader N.J., 2004: Stable isotopes in tree rings. Quaternary Science Reviews 23, 771-801.

Poussart P.M., Myneni S.C.B and Lanzirotti A, 2006: Tropical dendrochemistry: A novel approach to estimate age and growth from ringless trees. Geophysical Research Letters (doi:10.1029/2006GL026929).

Robertson I., Loader N.J., Froyd C.A., Zambatis N., Whyte I. and Woodborne S., 2006: The potential of the Baobab (Adansonia digitata L.) as a proxy climate archive. Applied Geochemistry 21, 1674-1680.

Robertson I., Froyd, C.A., Walsh R.P.D., Newbery D.M., Woodborne S. and Ong R.C., 2004: The dating of dipterocarp tree rings: establishing a record of carbon cycling and climatic change in the tropics. Journal of Quaternary Science 19(7), 657-664.

Walsh R.P.D. and Newbery D.M. 1999: The ecoclimatology of Danum, Sabah, in the context of the world’s rainforest regions, with particular reference to dry periods and their impact. Phil. Trans. R. Soc. Lond. B 354, 1869-1883.