The full programme book (PDF) - Royal Geographical Society

T3
Continental silicon cycling and Lake Baikal
V.N. Panizzo* 1 , G.E.A. Swann 1 , A.W. Mackay 2 , S. Roberts 1 , S. McGowan 1 and M.S.A.
Horstwood 3
1 School of Geography, University of Nottingham, University Park, Nottingham, NG27 2RD
2 Environmental Change Research Centre, Department of Geography, University College London,
Pearson Building, Gower Street, London, WC1E 6BT
3 NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, NG12 5GG
There has been a recent expansion in the application of silicon isotopes (δ 30 Si) in
environmental research. To date, most work has centred on marine systems in order to
understand modern and palaeo-silicon cycling and its link with carbon burial. Whilst other
studies have used δ 30 Si in terrestrial and riverine environments (De la Rocha, 2000;
Basile-Doelsch et al, 2005; Georg, 2006) few have investigated its use in lacustrine
systems (Alleman et al 2005; Street-Perrott et al, 2011; Swann et al, 2010; Opfergelt et al,
2011) despite its potential to revolutionise limnological research by providing a much
needed constraint on the aquatic silicon cycle, for which much remains unknown (Conley
2002; Strufy et al, 2009). This project provides one of the first detailed budgets of silicon
cycling in Lake Baikal, Siberia. Diatoms account for more than half of Lake Baikal’s
primary productivity (Mackay et al, 1998; Mackay et al, 2006) for which silicon is the most
essential nutrient in the formation of their frustules. In order to understand fully the
relationship between diatoms and silicon utilisation (e.g. lake productivity), we must first
have a clear grasp on modern day silicon cycling at the site and its catchment (e.g. endmembers).
Here we present the first detailed δ 30 Si of Lake Baikal’s dominant inflows,
outflows and the Selenga Delta. As measured by Multi-Collector Inter-Coupled Mass
Spectrometer (MC-ICP-MS). These data will be compared to the δ 30 Si of catchment
geology, seasonal lake waters and modern day diatoms in order to trace the route of
silicon throughout the Lake Baikal system. As Lake Baikal has seen an increase in both
anthropogenic and climate driven pressures in recent decades (e.g. nutrient loading in the
south basin and decreasing trends in lake ice duration) such data are essential in order to
understand future lake productivity, at this once pristine environment.
Keywords: Lake Baikal; silicon isotopes; diatoms; rivers; utilisation.
Alleman, L.Y., et al. 2005. J Great Lakes Res. 31: 509-519.
Basile-Doelsch, I., et al. 2005. Nature 433: 399-402.
Conley, D. 2002. Global Planet Change. 16: 1121.
De La Rocha C. 2000 Geochim Cosmochim Ac 64:2467-2477.
Georg, R.B., 2006a. Earth Planet Sc Lett. 249: 290-306.
Mackay, A.W., et al. 1998. Phil. Trans. of the Royal Society,353: 1011-1055.
Mackay, A.W., et al. 2006.Glob Change Biol. 12: 2297-2315.
Opfergelt, S., et al. 2011, Earth Planet Sc Lett. 305: 73-82.
Street-Perrott, F.A. et al. 2008. J Quaternary Sci. 23: 375-387.
Struyf, E., et al. 2009. Biogeosciences 6: 623-631.
Swann, G.E.A., et al. 2010. Quaternary Sci Rev. 29: 774-786.