Vertebrate Isotopes and the Environment (VISE)

SharkVISE seeks to test and develop our understanding of the relationship between the isotopic composition of sea water and vertebrate tissues (shark teeth and teleost otoliths), in particular, oxygen isotopic ratios which are thought to act as a proxy for the temperature of the seawater the organism lived in. VISE is also addressing the record of oxygen isotopes in conodonts to better understand their palaeoecology and use in Palaeozoic seawater temperature reconstructions.

Shark teeth, reasonably common in the fossil record over the past 400 million years, have been used extensively in isotopic studies as a consequence of the ‘conveyor belt’ production of individual teeth within a shark’s mouth during their life cycle and their high preservation potential. In collaboration with the Sea Life Centre network, the research team are analysing the teeth of a wide range of sharks and the tank waters in which they are housed to establish the reliability of shark teeth isotopic ratios as a proxy for seawater chemistry, and, importantly, look for any evidence of self fractionation within sharks. Previously, this field of research has been validated on the basis of wild caught specimens with little control on which body of water the individual sharks were in when they were mineralising their teeth. The study team will also conduct a series of taphonomic and processing experiments to see if the fossilisation and standard palaeontological processing methods adversely influence tooth composition.

Marine ecosystem response to the Eocene/Oligocene transition

Global atmospheric concentrations of carbon dioxide are rising at a rate unprecedented in the history of the Earth as a result of human activity. Today’s value of ~400 ppmv is higher than it has been for ~25 million years. 

Our ability to predict the effects of increased atmospheric carbon dioxide levels critically depends on understanding the interactions between the physical, chemical and biological processes that occur on our planet. Increased concentrations of atmospheric carbon dioxide cause a direct warming of the Earth’s surface. 

This warming, however, can significantly alter the rates at which carbon dioxide is itself transferred between the Earth’s chemical and biological carbon reservoirs. Changes in these rates may either enhance or reduce the current rise in atmospheric carbon dioxide concentrations, creating the potential for feedbacks within the climate system that are still poorly constrained.

Our understanding of these feedbacks is based upon the historical and geological record of past climate change. Geological data of ancient climate conditions has revealed numerous complex and often rapid changes in the Earth’s climate. 

This research project focuses on the causes of the most significant climate transition of the past 65 million years, when a continent-wide ice cap first appeared on Antarctica, 34 million years ago. 

The rapid growth of the Antarctic ice-sheet appears to have been triggered when a long-term decline in atmospheric carbon dioxide concentrations crossed a critical threshold of ~750ppmv. At this point various positive feedback mechanisms, such as increased marine primary productivity, caused a rapid cooling into a deep glacial state. 

We are seeking to understand the feedbacks between climatic cooling, Antarctic glaciation and marine primary productivity across this climate transition. In particular, this project uses the tiny fossil remains of single-celled marine algae called coccolithophores.

These algae live in the surface waters of the ocean and are responsible for a large portion of the photosynthesis, or “primary production”, of the world’s oceans. As a result they play a critical role in the uptake of carbon dioxide by the surface ocean from the atmosphere and its conversion into inorganic (calcium carbonate) and organic carbon.

They form the base of the marine food chain and variations in their productivity have large impacts on the chemistry of the oceans. By studying the abundance, distribution, evolution and chemistry of fossil coccolithophores, we aim to quantify changes in the biological productivity of the ocean and its role in removing carbon dioxide from the atmosphere and climate cooling. 

Understanding the relative importance of changes in marine primary productivity in Earth’s history will help us to predict its future role in reducing or accelerating anthropogenic climatic change.

Members of staff involved

Tom Dunkley Jones

Research students

  • Sufiah Sulaiman 
  • Katy Prentice (PhD student Imperial College; lead supervisor Tom Dunkley Jones)
  • Cherry Newsam (PhD student University College London; co-supervisor Tom Dunkley Jones)

Project funding

2013 University of Birmingham – University of Nottingham Strategic Collaboration Fund (£40k), Joint with Dr George Swann, UoN Geography; Antarctic ice-sheet controls on tropical Pacific nutrient cycling.

2013 ECORD Research Grant: The role of ocean productivity in carbon cycle changes through the Eocene/Oligocene Transition

2012-2013 Royal Society Small Grant (£15k): Paleogene marine calcareous phytoplankton: ecological dynamics through rapid climate events and long-term macroevolution;

2010-2013 Royal Society Dorothy Hodgkin Fellowship (£395k);

2012 NERC Ion Microprobe Facility Grant:IMF743/1012 Trace metal constraints on coccolithophore calcification mechanisms;

2011 NERC Ion Microprobe Facility Grant: IMF420/1010 Surface ocean productivity through the Eocene/Oligocene transition using the Sr/Ca composition of coccolith calcite.


Pälike, H., et al. 2012. A Cenozoic record of the equatorial Pacific carbonate compensation depth, Nature 488: 609-615, doi:10.1038/nature11360

Bown, P.R. and Dunkley Jones, T. 2012. Calcareous nannofossils from the Paleogene equatorial Pacific (IODP Expedition 320 Sites U1331-1334). J. Nannoplankton Res. 32(2):3-51.

Westerhold, T., Röhl, U., Wilkens, R., Pälike, H., Lyle, M., Dunkley Jones, T., Bown, P., Moore, T., Kamikuri, S., Acton, G., Ohneiser, C., Yamamoto, Y., Richter, C., Fitch, P., Scher, H., Liebrand, D. and the Expedition 320/321 Scientists. 2012. Revised composite depth scales and integration of IODP Sites U1331–U1334 and ODP Sites 1218–1220, Proceedings of the Integrated Ocean Drilling Program, 320/321, doi: 10.2204/iodp.proc.320321.201.2012.

Dunkley Jones, T., P. R. Bown, and P. N. Pearson. 2009. Exceptionally well preserved upper Eocene to lower Oligocene calcareous nannofossils (Prymnesiophyceae) from the Pande Formation (Kilwa Group), Tanzania, Journal of Systematic Palaeontology 7(4):359-411, doi:10.1017/S1477201909990010.

Dunkley Jones, T., Bown, P.R., Pearson, P.N., Wade, B.S., Coxall, H.K., and Lear, C.H. 2008. Major shifts in calcareous phytoplankton assemblages through the Eocene-Oligocene transition of Tanzania and their implications for low-latitude primary production, Paleoceanography 23, PA4204, doi:10.1029/2008PA001640.

Pearson, P. N. McMillan, I. K., Wade, B. S., Dunkley Jones, T., Coxall, H. K., Bown, P. R. and Lear, C. H. 2008. Extinction and environmental change across the Eocene/Oligocene boundary in Tanzania. Geology 36:179-182, doi:10.1130/G24308A.

Bown, P. R, Dunkley Jones, T., Lees, J.A., Pearson, P.N., Randell, R., Coxall, H.K., Mizzi, J., Nicholas, C., Karega, A., Singano, J., Wade, B.S. 2008. A calcareous microfossil Konservat-Lagerstätte from the Paleogene Kilwa Group of coastal Tanzania. GSA Bulletin 120:3-12,  doi:10.1130/B26261.1.

Key periods of data collection/fieldwork activity

Integrated Ocean Drilling Program (IODP) Expedition 320: Pacific Equatorial Age Transect. 2009. Shipboard scientist Tom Dunkley Jones

Tanzanian Drilling Project (2004-5). Expedition Scientist Tom Dunkley Jones

Opportunities (e.g. PhD proposals)

Tanzania Onshore Paleogene Integrated Coring (TOPIC); International Continental Scientific Drilling Program proposal. Co-proponent Tom Dunkley Jones. Proposal workshop September 2014, Dar-es-Salaam. 

Otoliths, the aragonitic inner ear ‘stones’ of fish, are also being analysed from a range of species. The variability in the isotopic composition of otoliths is widely used to identify the life-history dynamics of many different types of fish in the natural environment, and in the case of oxygen, to estimate temperature and palaeotemperatures of seawater masses. Otoliths are relatively common in some parts of the fossil record, particularly in the Jurassic and the Cretaceous, yet are under-utilised in isotope studies. Inter-taxon oxygen isotope variability is recognized, but the extent of this from a variety of taxa in the context of a constrained marine setting is poorly resolved.

Our current conodont work is focussed on Ordovician (Newfoundland), Silurian (UK) and Permian and Triassic (Greenland) material. Species isotopic variability in conodonts is starting to demonstrate the potential for reconstructing ancient water mass configurations. The work is also revealing the influence of processing and post-mortem effects on conodont oxygen isotopes.

Oxygen isotopes are analysed via ion microprobe and through our SILLA lab at the University of Birmingham.

Members of staff involved:

Ivan Sansom, James Wheeley, Ian Boomer

Project funding:

Sansom, I.J. and Wheeley, J.R. 2012. Oxygen isotopes in shark teeth: testing for intra-tooth variability and the impact of processing methods. NERC Ion Microprobe Facility IMF470/1012 (£11,250).

Smith, M.P., Wheeley, J.R. and Boomer, I. 2011. Constraining conodont d18O for marine palaeothermometry. NERC IMF414/1010 (~£22,500).

Žigaite, Ž. and Sansom, I.J., Wheeley, J.R., Boomer, I., Smith, M.P. 2011. VISE: Vertebrate Isotopes and the Environment. Marie Curie Intra-European Fellowship for Zivile Zigaite (£148,924).

Wheeley, J.R. 2010. Deciphering Paleozoic paleoenvironmental changes using stable and radiogenic isotope proxies. GEES funding for attending and organizing technical session at The Annual Meeting of the Geological Society of America, Denver, Colorado, 2010 (£1,600). GEES funding for attending and organizing technical session at The Annual Meeting of the Geological Society of America, Denver, Colorado, 2010 (£1,600).

Wheeley, J.R. 2010. Nitrogen and organic carbon isotopes for conodont palaeoecology. The Palaeontological Association Research Grant (£3,500).

Wheeley, J.R. and Smith, M.P. 2010. Nitrogen and organic carbon isotopes in early vertebrate hard tissues – elucidating the trophic position and life modes of vertebrates in Ordovician ecosystems. Royal Society Research Grant (£14,015).

Wheeley, J.R., Smith, M.P. and Boomer, I. 2009. Oxygen isotopes from conodont phosphate. NERC Isotope Geoscience Laboratories (NIGL) (~£500 in kind from NIGL).

Smith, M.P., Wheeley, J.R., Boomer, I. 2008. Conodonts as palaeotemperature indicators in Palaeozoic oceans? A proof-of-concept study. NERC IMF333/0508 (~£6,250).

Publications, reports, conference abstracts:

Wheeley, J.R., Smith, M.P. and Boomer, I. 2013. Oxygen isotope variability in Ordovician and Silurian conodonts. NAMS (North American Micropaleontology Society) 3. Houston, Texas.

Wheeley, J.R., Smith, M.P. and Boomer, I. 2012. Oxygen isotope variability in conodonts: implications for reconstructing Palaeozoic palaeoclimates and palaeoceanography. Journal of the Geological Society, London, 169: 239-250.

Wheeley, J.R.,Smith, M.P. and Boomer, I. 2012. d18O variability in Ordovician and Silurian conodonts: implications for Palaeozoic palaeoclimates.The Micropalaeontological Association Annual Meeting.

Wheeley, J.R., Smith, M.P and Boomer, I. 2010. Assessing the utility of ion microprobe analyses of conodont isotopes for ancient ocean palaeothermometry. GSA Denver, Colorado. Geological Society of America Abstracts with Programs, Vol. 42, No. 5, p. 514.

Wheeley, J.R., Smith, M.P. and Boomer, I. 2010. Conodonts as palaeothermometers in ancient oceans: tests and limitations. Third International Palaeontological Congress, London. Symposium: The Micropalaeontological Record of Global Change. Programme and Abstracts p. 409.

Wheeley, J.R.,Smith, M.P. and Boomer, I. 2010. NERC Scientific Facilities and Technology Ion Microprobe Facility. University of Edinburgh. Annual Science Report pp. 53–54.

Wheeley, J.R., Smith, M.P. and Boomer, I. 2009. Conodonts as palaeothermometers of ancient oceans? Palaeontological Association 53rd Annual Meeting. Palaeontology Newsletter, 72: 36..

Key periods of data collection/fieldwork activity:

2008 to present

Opportunities (e.g. PhD proposals):

We are always interested in hearing from potential PhD applicants in the field of vertebrate isotopes. Email or if you are in the position to apply for a research position in this area.