Staff Profile

Pc4_29_3.gif (203K)

Selected References


R.E.M. Rickaby

University Lecturer in Biogeochemistry

My principal research interest is to further the understanding of past changes in climate and atmospheric carbon dioxide (pCO2) on a variety of timescales. In order to understand the history of the ocean and climate, I use the concentration of trace elements (e.g. Sr, Cd, Ba and Zn) in marine biogenic calcites which have the potential to act as tools to probe past ocean conditions and related climate change. The trace element content of these biological carbonates reflects two factors: the seawater metal chemistry in which the organism was growing, and how the trace elements are partitioned into the biological carbonate. I have started to challenge the traditional view that the partitioning of trace elements occurs according to thermodynamic predictions for inorganic calcite and propose that the chemistry of the biogenic calcite is instead controlled by discrimination between similarly sized ions during the biological calcification process. During the course of my research, I discovered an unexpected temperature control on the incorporation of Cd into planktonic foraminiferal calcite. Similarly, the Sr/Ca of coccolithophore calcite from contrasting areas of the ocean shows significant variations despite the uniform concentration of Sr and Ca within the modern ocean. An overview of trace metal incorporation into biogenic calcites, which reveals that the uptake varies according to many different factors depending on the trace metal or organism, has inspired me to investigate the cellular ion pumping systems associated with biomineralisation. This has become a new research goal. In addition, I aim to couple these ideas about biomineralisation with further development of new mass-spectrometric techniques, to refine a range of new metal and isotopic proxies which may be used to characterise different aspects of the ocean system on a variety of timescales.

  • Rickaby, R. E. M.; Schrag, D. P.; Zondervan, I.; Riebesell, U., Growth rate dependence of Sr incorporation during calcification of Emiliania huxleyi, Global Biogeochem. Cycles, 16 (1), 2001GB001408, 2002.

  • Rickaby, R. E. M. & D. P. Schrag, Biological control on trace element partitioning into biogenic calcites, J. Inorg. Biochem., 86 (1) 401, 2001

  • Elderfield, H., & R. E. M. Rickaby, Oceanic Cd/P ratio and nutrient utilisation in the glacial Southern Ocean, Nature, 405, 305-310, 2000.

  • Rickaby, R. E. M., M. J. Greaves, & H. Elderfield, Cd in planktonic and benthic foraminiferal shells by thermal ionisation mass-spectrometry, Geochim. Cosmochim. Acta, 64, No. 7, 1229-1236, 2000.

  • Rickaby, R. E. M., & H. Elderfield, Planktonic Cd/Ca: Paleonutrients or paleotemperature? Paleoceanography, 14, vol. 3, 293-303, 1999.

ros.gif (28K)